A review on the mechanisms underlying the antitumor effects of natural products by targeting the endoplasmic reticulum stress apoptosis pathway.

Cancer poses a substantial risk to human life and wellbeing as a result of its elevated incidence and fatality rates. Endoplasmic reticulum stress (ERS) is an important pathway that regulates cellular homeostasis. When ERS is under- or overexpressed, it activates the protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK)-, inositol-requiring enzyme 1 (IRE1)- and activating transcription Factor 6 (ATF6)-related apoptotic pathways to induce apoptosis. Tumor cells and microenvironment are susceptible to ERS, making the modulation of ERS a potential therapeutic approach for treating tumors. The use of natural products to treat tumors has substantially progressed, with various extracts demonstrating antitumor effects. Nevertheless, there are few reports on the effectiveness of natural products in inducing apoptosis by specifically targeting and regulating the ERS pathway. Further investigation and elaboration of its mechanism of action are still needed. This paper examines the antitumor mechanism of action by which natural products exert antitumor effects from the perspective of ERS regulation to provide a theoretical basis and new research directions for tumor therapy.

[Ozone Pollution Characteristics and Formation Mechanism in a Typical Tropical Seaside City].

To investigate the pollution characteristics and formation mechanism of ambient air ozone(O3) in a typical tropical seaside city, we conducted an observational experiment on O3 and its precursors at an urban site in Haikou, Hainan Province, from June to October 2019. The O3 pollution characteristics were analyzed comprehensively; the O3-NOx-VOCs sensitivities and key precursors were determined, and the control strategies for O3 pollution were carried out. The results were as follows:1 O3 pollution in Haikou mainly occurred in September and October, with daily maximum 8-h O3 concentrations in the range of 39-190 µg·m-3, and the daily variation in O3 was unimodal, peaking at approximately 14:00. 2 The concentrations of NO2 and VOCs were higher during O3 pollution episodes than their respective mean values in Haikou City. The increased O3 precursor concentrations were an important factor leading to O3 pollution, whereas O3 pollution was also influenced by regional transport, with pollutants mainly transported from the northeastern part of Haikou City. 3 O3-NOx-VOCs sensitivity in Haikou City was in the VOCs and NOx transitional regime, and the most sensitive precursors in various months were different. O3 formation in September was sensitive to anthropogenic VOCs the most; however, in October it was sensitive to NOx. 4 In the future, the reduction ratio of VOCs to NOx should be 1:1-4:1 to control O3 pollution effectively in Haikou.

Marsdenia tenacissima extract induces endoplasmic reticulum stress-associated immunogenic cell death in non-small cell lung cancer cells through targeting AXL.

ETHNOPHARMACOLOGICAL RELEVANCE: Marsdenia Tenacissima (Roxb.) Wight et Arn. is a traditional Chinese medicine. Its standardized extract (MTE), with the trade name Xiao-Ai-Ping injection, is widely used for cancer treatment. The pharmacological effects of MTE-inducing cancer cell death have been primarily explored. However, whether MTE triggers tumor endoplasmic reticulum stress (ERS)-associated immunogenic cell death (ICD) is unknown. AIM OF THE STUDY: To determine the potential role of endoplasmic reticulum stress in the anti-cancer effects of MTE, and uncover the possible mechanisms of endoplasmic reticulum stress-associated immunogenic cell death induced by MTE. MATERIAL AND METHODS: The anti-tumor effects of MTE on non-small cell lung cancer (NSCLC) were examined through CCK-8 and wound healing assay. Network pharmacology analysis and RNA-sequencing (RNA seq) were performed to confirm the biological changes of NSCLCs after MTE treatment. Western blot, qRT-PCR, reactive oxygen species (ROS) assay, and mitochondrial membrane potential (MMP) assay were used to explore the occurrence of endoplasmic reticulum stress. Immunogenic cell death-related markers were tested by ELISA and ATP release assay. Salubrinal was used to inhibit the endoplasmic reticulum stress response. SiRNA and bemcentinib (R428) were used to impede the function of AXL. AXL phosphorylation was regained by recombinant human Gas6 protein (rhGas6). The effects of MTE on endoplasmic reticulum stress and immunogenic cell death response were also proved in vivo. The AXL inhibiting compound in MTE was explored by molecular docking and confirmed by Western blot. RESULTS: MTE inhibited cell viability and migration of PC-9 and H1975 cells. Enrichment analysis identified that differential genes after MTE treatment were significantly enriched in endoplasmic reticulum stress-related biological processes. MTE decreased mitochondrial membrane potential (MMP) and increased ROS production. Meanwhile, endoplasmic reticulum stress-related proteins (ATF6, GRP-78, ATF4, XBP1s, and CHOP) and immunogenic cell death-related markers (ATP, HMGB1) were upregulated, and the AXL phosphorylation level was suppressed after MTE treatment. However, when salubrinal (an endoplasmic reticulum stress inhibitor) and MTE were co-treated cells, the inhibitory effects of MTE on PC-9 and H1975 cells were impaired. Importantly, inhibition of AXL expression or activity also promotes the expression of endoplasmic reticulum stress and immunogenic cell death-related markers. Mechanistically, MTE induced endoplasmic reticulum stress and immunogenic cell death by suppressing AXL activity, and these effects were attenuated when AXL activity recovered. Moreover, MTE significantly increased the expression of endoplasmic reticulum stress-related markers in LLC tumor-bearing mouse tumor tissues and plasma levels of ATP and HMGB1. Molecular docking illustrated that kaempferol has the strongest binding energy with AXL and suppresses AXL phosphorylation. CONCLUSION: MTE induces endoplasmic reticulum stress-associated immunogenic cell death in NSCLC cells. The anti-tumor effects of MTE are dependent upon endoplasmic reticulum stress. MTE triggers endoplasmic reticulum stress-associated immunogenic cell death by inhibiting AXL activity. Kaempferol is an active component that inhibits AXL activity in MTE. The present research revealed the role of AXL in regulating endoplasmic reticulum stress and enriched the anti-tumor mechanisms of MTE. Moreover, kaempferol may be considered a novel AXL inhibitor.

Dandelion extract inhibits triple-negative breast cancer cell proliferation by interfering with glycerophospholipids and unsaturated fatty acids metabolism.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype with limited treatment options and a poor prognosis. TNBC exists widely reprogrammed lipid metabolism, and its metabolic-associated proteins and oncometabolites are promising as potential therapeutic targets. Dandelion (Taraxacum mongolicum) is a classical herbal medicine used to treat breast diseases based on traditional Chinese medicine theory and was reported to have antitumor effects and lipid regulatory capacities. Our previous study showed that dandelion extract was effective against TNBC. However, whether dandelion extract could regulate the lipid metabolisms of TNBC and exert its antitumor effects via interfering with lipids metabolism remained unclear. In this study, an integrated approach combined with network pharmacology and multi-omics techniques (including proteomics, metabolomics, and lipidomics) was performed to investigate the potential regulatory mechanisms of dandelion extract against TNBC. We first determined the antitumor effects of dandelion extract in vitro and in vivo. Then, network pharmacology analysis speculated the antitumor effects involving various metabolic processes, and the multi-omics results of the cells, tumor tissues, and plasma revealed the changes in the metabolites and metabolic-associated proteins after dandelion extract treatment. The alteration of glycerophospholipids and unsaturated fatty acids were the most remarkable types of metabolites. Therefore, the metabolism of glycerophospholipids and unsaturated fatty acids, and their corresponding proteins CHKA and FADS2, were considered the primary regulatory pathways and biomarkers of dandelion extract against TNBC. Subsequently, experimental validation showed that dandelion extract decreased CHKA expression, leading to the inhibition of the PI3K/AKT pathway and its downstream targets, SREBP and FADS2. Finally, the molecular docking simulation suggested that picrasinoside F and luteolin in dandelion extract had the most highly binding scores with CHKA, indicating they may be the potential CHKA inhibitors to regulate glycerophospholipids metabolisms of TNBC. In conclusion, we confirmed the antitumor effects of dandelion extract against TNBC cells in vitro and demonstrated that dandelion extract could interfere with glycerophospholipids and unsaturated fatty acids metabolism via downregulating the CHKA expression and inhibiting PI3K/AKT/SREBP/FADS2 axis.

Marsdenia tenacissima extract disturbs the interaction between tumor-associated macrophages and non-small cell lung cancer cells by targeting HDGF.

ETHNOPHARMACOLOGICAL RELEVANCE: Marsdenia tenacissima (Roxb.) Wight et Arn. is a traditional Chinese herbal medicine, and its water-soluble ingredient Marsdenia tenacissima extract (MTE), was widely used for cancer treatment. The multi-pharmacological efficacies and mechanisms of MTE in directly inhibiting tumor cells have been extensively studied. However, the anti-tumor effects of MTE in the tumor-associated macrophages (TAMs) microenvironment remain unclear. AIM OF THE STUDY: To uncover the role of hepatoma-derived growth factor (HDGF) in the interaction between TAMs and non-small cell lung cancer (NSCLC) cells. To evaluate the anti-tumor effects of MTE on the vicious crosstalk between TAMs and NSCLC by targeting HDGF. MATERIALS AND METHODS: HDGF-overexpression PC-9 and H292 NSCLC cell lines were constructed and verified. RNA-sequencing (RNA-seq) was performed in HDGF-overexpression PC-9 cells to probe the differential expression of genes. THP-1-derived macrophages were characterized using specific markers after stimulation with phorbol-12-myristate 13-acetate (PMA) and rhIL-4 or rhHDGF. The role of HDGF both in NSCLC cells and TAMs was determined using approaches like Western blot, qRT-PCR, ELISA, and flow cytometry. The interaction between tumor cells and TAMs were assessed by indirect co-culture H1975, PC-9 cells with M2 type macrophages. The effects of MTE on anti-tumor and macrophage polarization were evaluated in vitro and in vivo. RESULTS: RNA-seq results identified IL-4 as a critical response to HDGF in NSCLC. HDGF induced macrophages polarizing toward M2 type, and promoted NSCLC cells proliferation, migration and invasion in vitro. On the one hand, HDGF dose-dependently promoted IL-4 expression in NSCLC cells. On the other hand, HDGF induced M2 macrophage polarization through the IL-4/JAK1/STAT3 signaling pathway. MTE treatment significantly decreased the expression and secretion of HDGF in NSCLC cells. Meanwhile, MTE treatment led to M2 macrophage repolarization, as evidenced by decreased expression of M2 markers and increased levels of M1 markers. Importantly, MTE treatment significantly suppressed tumor development in C57BL/6 mice bearing Lewis lung cancer (LLC) cells in vivo, accompanied by decreased plasma HDGF levels, reduced M2 macrophages infiltration and increased M1 macrophages proportion in mice tumor tissues. CONCLUSIONS: HDGF upregulated IL-4 expression in NSCLC cells, and promoted M2 polarization by the IL-4/JAK1/STAT3 signaling pathway in macrophages. MTE disturbed the interaction between NSCLC and TAMs in vitro, and inhibited tumor growth in vivo, at least in part, by suppressing HDGF. Therefore, our present study revealed a novel anti-tumor mechanism of MTE through inhibiting HDGF expression and enhancing macrophage polarization from M2 to M1 phenotype.

Metabolic reprogramming by traditional Chinese medicine and its role in effective cancer therapy.

Metabolic reprogramming, characterized by alterations of cellular metabolic patterns, is fundamentally important in supporting the malignant behaviors of cancer cells. It is considered as a promising therapeutic target against cancer. Traditional Chinese medicine (TCM) and its bioactive components have been used in cancer therapy for an extended period, and they are well-known for their multi-target pharmacological functions and fewer side effects. However, the detailed and advanced mechanisms underlying the anticancer activities of TCM remain obscure. In this review, we summarized the critical processes of cancer cell metabolic reprogramming, including glycolysis, mitochondrial oxidative phosphorylation, glutaminolysis, and fatty acid biosynthesis. Moreover, we systemically reviewed the regulatory effects of TCM and its bioactive ingredients on metabolic enzymes and/or signal pathways that may impede cancer progress. A total of 46 kinds of TCMs was reported to exert antitumor effects and/or act as chemosensitizers via regulating metabolic processes of cancer cells, and multiple targets and signaling pathways were revealed to contribute to the metabolic-modulating functions of TCM. In conclusion, TCM has its advantages in ameliorating cancer cell metabolic reprogramming by its poly-pharmacological actions. This review may shed some new light on the explicit recognition of the mechanisms of anticancer actions of TCM, leading to the development of natural antitumor drugs based on reshaping cancer cell metabolism.

Taraxacum mongolicum extract inhibited malignant phenotype of triple-negative breast cancer cells in tumor-associated macrophages microenvironment through suppressing IL-10 / STAT3 / PD-L1 signaling pathways.

ETHNOPHARMACOLOGICAL RELEVANCE: Triple-negative breast cancer (TNBC) is the most aggressive and the worst prognosis breast cancer with limited treatment options. Taraxacum mongolicum (also called dandelion) is a traditional Chinese medicine has been used to treat mastitis, breast abscess, and hyperplasia of mammary glands since ancient times. In modern pharmacological research, dandelion has been proven with anti-breast cancer activities. We previously reported that dandelion extract could induce apoptosis in TNBC cells. However, its anti-tumor effects and mechanisms in the tumor microenvironment have not yet been elucidated. AIM OF THE STUDY: Tumor-associated macrophages (TAMs) play an important role in regulating the interaction between tumor cells and the immune system. The present study aimed to investigate the effects and mechanisms of dandelion extract on TNBC cells under the microenvironment of TAMs, as well as its influence on the polarization of M2 macrophages. MATERIALS AND METHODS: M2 macrophages were induced by phorbol-12-myristate 13-acetate (PMA) and interleukin 4 (IL-4), and verified by flow cytometry, quantitative RT-PCR (qRT-PCR), Western blotting, and ELISA. MDA-MB-231 and MDA-MB-468 TNBC cells were co-cultured with the supernatant of M2 macrophage which providing the TAMs microenvironment. The antitumor activity of dandelion extract in TNBC cells was evaluated by MTT assay. The invasive and migratory capacity of TNBC cells was measured by transwell assays. The expression of protein and gene was assessed by Western blotting and qRT-PCR, respectively. RESULTS: TAMs microenvironment promoted the proliferation, migration, and invasion of TNBC cells. However, dandelion extract inhibited the malignant property of MDA-MB-231 and MDA-MB-468 cells induced by TAMs. Both of TAMs and IL-10 caused STAT3 activation and PD-L1 higher expression, the immunosuppressive molecules in TNBC cells, and this effect can be attenuated by IL-10 neutralizing antibody. Dandelion extract exerted inhibition on STAT3 and PD-L1 in TNBC cells under TAMs microenvironment. Furthermore, in M2 macrophages, dandelion extract remarkably promoted the expression of M1-like marker TNF-α, IL-8, and iNOS, but reduced M2-like marker IL-10, CD206, Arginase-1, and TGF-ß. CONCLUSION: Dandelion extract inhibited the proliferation, migration and invasion of TNBC cells in TAMs microenvironment through suppressing IL-10/STAT3/PD-L1 immunosuppressive signaling pathway. Furthermore, dandelion extract promoted the polarization of macrophages from M2 to M1 phenotype. Thus, our results indicated that dandelion may serve as a promising therapeutic strategy for TNBC by modulating tumor immune microenvironment.

A validated high-performance liquid chromatography-tandem mass spectrometry method for quantification of gefitinib and its main metabolites in xenograft mouse tumor: Application to a pharmacokinetics study.

Monitoring gefitinib and its metabolites may help to explore the underlying mechanisms of gefitinib resistance. The concentration of gefitinib and its metabolites in tumor tissues could influence its anticancer activities more than that in the plasma. In the present study, a rapid and specific HPLC-MS/MS method was developed and validated to simultaneously determine gefitinib, M387783, M523595, M537194 and M608236 in tumor tissues of H1975 human lung cancer xenografts of nude mice. The established HPLC-MS/MS method was validated for specificity, linearity, accuracy and precision, matrix effect and recovery, carryover and dilution integrity, and analyte stability. The standard curves were linear (r2 ≥ 0.99) over the range of 0.5-100 ng/mL for M608236 and 1-200 ng/mL for gefitinib, M523595 and M537194 as well as M387783. The accuracy ranged from -8.35 to 6.03% relative error; and the precision was <15% relative standard deviation. Recoveries (87.74-99.96%) and matrix effects (86.60-106.40%) were satisfactory in the biological matrix examined. Stability studies showed that the analytes were stable during the assay procedure and storage. Finally, the validated method was successfully applied to study the pharmacokinetics profiles for gefitinib and its metabolites in nonsmall cell lung cancer (NSCLC) xenograft mouse tumors. Meanwhile, MTT assay showed that gefitinib had a more powerful inhibitory effect than its four major metabolites in H1975 NSCLC cells. This validated HPLC-MS/MS method may be applied to help understand the mechanisms of gefitinib resistance in EGFR-mutant nonsmall cell lung cancer.

Marsdenia tenacissima extract induces apoptosis and suppresses autophagy through ERK activation in lung cancer cells.

BACKGROUND: Marsdenia tenacissima is an herb medicine which has been utilized to treat malignant diseases for decades. The M. tenacissima extract (MTE) shows significant anti-proliferation activity against non-small cell lung cancer (NSCLC) cells, but the underlying mechanisms remain unclear. In this study, we explored the potential anti-proliferation mechanisms of MTE in NSCLC cells in relation to apoptosis as well as autophagy, which are two critical forms to control cancer cell survival and death. METHODS: The proliferation of H1975 and A549 cells was evaluated by MTT assay. Cell apoptosis was assessed by Annexin V and PI staining, Caspase 3 expression and activity. Autophagy flux proteins were detected by Western blot with or without autophagy inducer and inhibitor. Endogenous LC3-II puncta and LysoTracker staining were monitored by confocal microscopy. The formation of autophagic vacuoles was measured by acridine orange staining. ERK is a crucial molecule to interplay with cell autophagy and apoptosis. The role of ERK on cell apoptosis and autophagy influenced by MTE was determined in the presence of MEK/ERK inhibitor U0126. RESULTS: The significant growth inhibition and apoptosis induction were observed in MTE treated NSCLC cells. MTE induced cell apoptosis coexisted with elevated Caspase 3 activity. MTE also impaired autophagic flux by upregulated LC3-II and p62 expression. Autophagy inducer EBSS could not abolish the impaired autophagic flux by MTE, while it was augmented in the presence of autophagy inhibitor Baf A1. The autophagosome-lysosome fusion was blocked by MTE via affecting lysosome function as evidenced by decreased expression of LAMP1 and Cathepsin B. The molecule ERK became hyperactivated after MTE treatment, but the MEK/ERK inhibitor U0126 abrogated autophagy inhibition and apoptosis induction caused by MTE, suggested that ERK signaling pathways partially contributed to cell death caused by MTE. CONCLUSION: Our results demonstrate that MTE caused apoptosis induction as well as autophagy inhibition in NSCLC cells. The activated ERK is partially associated with NSCLC apoptotic and autophagic cell death in response to MTE treatment. The present findings reveal new mechanisms for the anti-tumor activity of MTE against NSCLC.

A Methylthio-Functionalized-MOF Photocatalyst with High Performance for Visible-Light-Driven H2 Evolution.

Recently, the emergence of photoactive metal-organic frameworks (MOFs) has given great prospects for their applications as photocatalytic materials in visible-light-driven hydrogen evolution. Herein, a highly photoactive visible-light-driven material for H2 evolution was prepared by introducing methylthio terephthalate into a MOF lattice via solvent-assisted ligand-exchange method. Accordingly, a first methylthio-functionalized porous MOF decorated with Pt co-catalyst for efficient photocatalytic H2 evolution was achieved, which exhibited a high quantum yield (8.90 %) at 420 nm by use sacrificial triethanolamine. This hybrid material exhibited perfect H2 production rate as high as 3814.0 µmol g-1 h-1 , which even is one order of magnitude higher than that of the state-of-the-art Pt/MOF photocatalyst derived from aminoterephthalate.

Bu-Fei decoction and modified Bu-Fei decoction inhibit the growth of non-small cell lung cancer, possibly via inhibition of apurinic/apyrimidinic endonuclease 1.

Human apurinic/apyrimidinic endonuclease 1 (APE1) is a ubiquitous multifunctional protein, which possesses DNA repair and redox activities. High levels of APE1 are associated with chemo­ and radioresistance, and poor prognosis in various types of cancer, including non­small cell lung cancer (NSCLC). Bu­Fei decoction (BFD) is a traditional Chinese herbal formula, which is believed to supplement Qi, clear away heat and nourish the lungs. BFD and modified Bu­Fei decoction (MBFD) have been used in China to treat patients with lung cancer. The present study aimed to evaluate the potential antitumor effects of BFD and MBFD on NSCLC in vitro and in vivo. In addition, the possible contribution of APE1 was examined. MTT assay was used to investigated the anti-tumor activity of BFD and MBFD on H1975 and H292 NSCLC cell lines. The DNA damage of cells in the control and the experimental groups was detected using comet assay. The in vivo anti-tumor effects of BFD and MBFD were evaluated in a NSCLC tumor nude mouse xenograft model. Polymerase chain reaction (PCR), reverse transcription­quantitative PCR (RT­qPCR) analysis and western blot analysis were applied to analyze the mRNA and protein expression levels of APE1 in H1975 and H292 cells, so as to the xenograft tumor tissues. The concentration of APE1 in mice plasma was determined using enzyme linked immunosorbent assay (ELISA). In vitro, BFD and MBFD inhibited the growth of cultured H1975 and H292 NSCLC cells. The results of a comet assay revealed that BFD and MBFD increased DNA damage. Furthermore, the expression levels of APE1 were decreased in response to BFD and MBFD at the mRNA and protein levels. In mice carrying NSCLC xenografts, BFD and MBFD inhibited tumor growth and decreased APE1 expression. In addition, in normal human lung bronchial epithelial BEAS­2B cells, the half maximal inhibitory concentrations of BFD and MBFD were much higher compared with in NSCLC cells, and they had no effect on DNA damage. These results suggested that BFD and MBFD may inhibit the growth of NSCLC, possibly by inhibiting APE1 expression.

Shugan Liangxue Decoction () Down-Regulates Estrogen Receptor α Expression in Breast Cancer Cells.

OBJECTIVE: To observe the effect of Shugan Liangxue Decoction (, SGLXD) on estrogen receptor α (ERα) in human breast cancer cells. METHODS: The effect of SGLXD (0.85-5.10 mg/mL) on the proliferation of breast cancer cells were evaluated by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. The nuclear ERα protein levels in MCF-7, T47D and ZR-75-1 cells which treated by SGLXD for 24 h were examined by western blot and immunofluorescence assay. MCF-7 and MDA-MB-231 cells were treated by 17ß-estradiol (E2) with or without SGLXD, for 24 h, and the E2 targeted genes c-myc and bcl-2 protein product was evaluated by western blot. RESULTS: SGLXD showed dose-dependent inhibition on the proliferation of MCF-7, T47D and ZR-75-1 cells, but did not inhibit the proliferation of MDA-MB-231 cells. Furthermore, the promotive effect on cell growth induced by E2 was also significantly inhibited by SGLXD treatment. With the treatment of 1.70, 3.40, 5.10 mg/mL SGLXD, the nuclear ERα protein level was reduced to 88.1%, 70.4% and 60.9% in MCF-7 cells, and was decreased to 43.0%, 38.4% and 5.9% in ZR-75-1 cells as compared with the control group. In T47D cells, the nuclear ERα protein was down-regulated to 51.3% and 4.3% by 3.40 and 5.10 mg/mL SGLXD treatment. The down-regulative effect of SGLXD on nuclear ERα was confirmed by immunofluorescence assay. SGLXD decreased the protein product of c-myc and bcl-2. CONCLUSIONS: SGLXD may exhibit selective inhibition effect on the proliferation of ER positive breast cancer cells. SGLXD reduced the nuclear ERα expression and the protein product of E2 target gene c-myc and bcl-2.

The role of endothelial lipase in lipid metabolism, inflammation, and cancer.

Endothelial lipase (LIPG) plays a critical role in lipoprotein metabolism, cytokine expression, and the lipid composition of cells. Thus far, the extensive investigations of LIPG have focused on its mechanisms and involvement in metabolic syndromes such as atherosclerosis. However, recent developments have found that LIPG plays a role in cancer. This review summarizes the field of LIPG study. We focus on the role of LIPG in lipid metabolism and the inflammatory response, and highlight the recent insights in its involvement in tumor progression. Finally, we discuss potential therapeutic strategies for targeting LIPG in cancer, and the therapeutic potential of LIPG as a drug target.

Marsdenia tenacissima extract overcomes Axl- and Met-mediated erlotinib and gefitinib cross-resistance in non-small cell lung cancer cells.

Tyrosine kinase inhibitors (TKIs) are an effective treatment strategy for non-small cell lung cancer (NSCLC) patients harboring mutations that result in constitutive activation of the epidermal growth factor receptor (EGFR). However, most patients eventually develop resistance to TKIs. This occurs due to additional EGFR mutations or the activation of bypass signaling pathways. In our previous work, we demonstrated that Marsdenia tenacissima extract (MTE) restored gefitinib sensitivity in resistant NSCLC cells with EGFR T790M or K-ras mutations. However, the potential efficacy of MTE in NSCLC cells with resistance mediated by Axl and c-Met, and the related molecular mechanisms need to be elucidated. In this study we evaluated the ability of MTE to restore erlotinib/gefitinib sensitivity in TKI resistant HCC827/ER cells and xenograft mice models. Our results demonstrate that MTE overcomes erlotinib and gefitinib resistance driven by Axl and c-Met in vitro and in vivo. Combination therapy significantly suppressed EGFR downstream molecules and the c-Met and Axl activated bypass signaling pathways. Moreover, we observed that MTE is more efficient at restoring resistance to erlotinib than gefitinib. As the Axl and c-Met mediated bypass pathways share the same downstream signaling cascade as EGFR, simultaneous targeting of these pathways is a promising strategy to overcome acquired resistance of TKIs. Our results demonstrate that MTE treatment attenuates Axl phosphorylation and the associated epithelial-mesenchymal transition, suggesting MTE treatment may be a potential therapeutic strategy for overcoming erlotinib and gefitinib cross-resistance in NSCLC, especially for erlotinib resistance.

Taraxacum mongolicum extract induced endoplasmic reticulum stress associated-apoptosis in triple-negative breast cancer cells.

BACKGROUND: Triple-negative breast cancer (TNBC) is an aggressive and deadly breast cancer subtype with limited treatment options. It is necessary to seek complementary strategies for TNBC management. Taraxacum mongolicum, commonly named as dandelion, is a herb medicine with anti-cancer activity and has been utilized to treat mammary abscess, hyperplasia of mammary glands from ancient time in China, but the scientific evidence and action mechanisms still need to be studied. AIM OF THE STUDY: This study was intended to investigate the therapeutic effect and molecular mechanisms of dandelion extract in TNBC cell line. METHODOLOGY: Dandelion extract was prepared and purified, and then its chemical composition was determined. Cell viability was evaluated by MTT assay. Analysis of cell apoptosis and cell cycle was assessed by flow cytometry. The expression levels of mRNA and proteins were determined by real-time PCR and Western blotting, respectively. Caspase inhibitor Z-VAD-FMK and CHOP siRNA were used to confirm the cell apoptosis induced by dandelion extract. RESULTS: Dandelion extract significantly decreased MDA-MB-231cell viability, triggered G2/M phase arrest and cell apoptosis. Concurrently, it caused a markedly increase of cleaved caspase-3 and PARP proteins. Caspase inhibitor Z-VAD-FMK abolished the apoptosis triggered by dandelion extract. The three ER stress-related signals were strongly induced after dandelion treatment, including increased mRNA expressions of ATF4, ATF6, XBP1s, GRP78 and CHOP genes, elevated protein levels of phosphorylated PERK, eIF-2α, IRE1, as well as the downstream molecules of CHOP and GRP78. MDA-MB-231 cells transfected with CHOP siRNA significantly reduced apoptosis induced by dandelion extract. The underlying mechanisms at least partially ascribe to the strong activation of PERK/p-eIF2α/ATF4/CHOP axis. CONCLUSION: ER stress related cell apoptosis accounted for the anti-cancer effect of dandelion extract, and these findings support dandelion extract might be a potential therapeutic approach to treat TNBC.

Tumor-associated myoepithelial cells promote the invasive progression of ductal carcinoma in situ through activation of TGFß signaling.

The normal myoepithelium has a tumor-suppressing nature and inhibits the progression of ductal carcinoma in situ (DCIS) into invasive ductal carcinoma (IDC). Conversely, a growing number of studies have shown that tumor-associated myoepithelial cells have a tumor-promoting effect. Moreover, the exact role of tumor-associated myoepithelial cells in the DCIS-to-IDC development remains undefined. To address this, we explored the role of tumor-associated myoepithelial cells in the DCIS-to-IDC progression. We developed a direct coculture system to study the cell-cell interactions between DCIS cells and tumor-associated myoepithelial cells. Coculture studies indicated that tumor-associated myoepithelial cells promoted the invasive progression of a DCIS cell model in vitro, and mechanistic studies revealed that the interaction with DCIS cells stimulated tumor-associated myoepithelial cells to secrete TGFß1, which subsequently contributed to activating the TGFß/Smads pathway in DCIS cells. We noted that activation of the TGFß signaling pathway promoted the epithelial-mesenchymal transition, basal-like phenotypes, stemness, and invasiveness of DCIS cells. Importantly, xenograft studies further demonstrated that tumor-associated myoepithelial cells enhanced the DCIS-to-IDC progression in vivo Furthermore, we found that TGFß-mediated induction of oncogenic miR-10b-5p expression and down-regulation of RB1CC1, a miR-10b-5p-targeted tumor-suppressor gene, contributed to the invasive progression of DCIS. Our findings provide the first experimental evidence to directly support the paradigm that altered DCIS-associated myoepithelial cells promote the invasive progression of DCIS into IDC via TGFß signaling activation.

Chinese medicine Bu-Fei decoction attenuates epithelial-mesenchymal transition of non-small cell lung cancer via inhibition of transforming growth factor ß1 signaling pathway in vitro and in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Traditional Chinese medicine Bu-Fei decoction (BFD) has been utilized to treat patients with Qi deficiency for decades, with the advantages of invigorating vital energy, clearing heat-toxin and moistening lung, etc. According to previous clinical experience and trials, BFD has been found to indeed improve life quality of lung cancer patients and prolong survival time. Nevertheless, little is known on its potential mechanisms so far. Being regarded as a pivotal cytokine in the tumor microenvironment, transforming growth factor ß (TGF-ß) stands out as a robust regulator of epithelial-mesenchymal transition (EMT), which is closely linked to tumor progression. AIM OF THE STUDY: The present study was designed to explore whether BFD antagonized EMT via blocking TGF-ß1-induced signaling pathway, and then help contribute to create a relatively steady microenvironment for confining lung cancer. MATERIALS AND METHODS: This experiment was performed in lung adenocarcinoma A549 cells both in vitro and in vivo. In detail, the influences mediated by TGF-ß1 alone or in combination with different concentrations of BFD on migration were detected by wound healing and transwell assays, and the effects of BFD on cell viability were determined by cell counting kit-8 (CCK-8) assay. TGF-ß1, EMT relevant proteins and genes were evaluated by western blotting, confocal microscopy, quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC) and enzyme-linked immuno sorbent assay (ELISA). Female BALB/C nude mice were subcutaneously implanted A549 cells and given BFD by gavage twice daily for 28 days. The tumor volume was monitored every 4 days to draw growth curve. The tumor weight, expression levels of EMT-related protein in tumor tissues and TGF-ß1 serum level were evaluated, respectively. RESULTS: BFD only exerted minor effects on A549 cell proliferation and this was in accordance with the in vivo result, which showed that the tumor growth and weight were not be restrained by BFD administration. However, the data elucidated that BFD could dose-dependently suppress EMT induced by TGF-ß1 in vitro via attenuating canonical Smad signaling pathway. In the A549 xenograft mouse model, BFD also inhibited protein markers that are associated with EMT and TGF-ß1 secretion into serum. CONCLUSIONS: Based on these above data, the conclusion could be put forward that BFD probably attenuated TGF-ß1 mediated EMT in A549 cells via decreasing canonical Smad signaling pathway both in vitro and in vivo, which may help restrain the malignant phenotype induced by TGF-ß1 in A549 cells to some extent.

Recent highlights of Chinese medicine for advanced lung cancer.

Owing to its unique superiority in improving quality of life and prolonging survival time among advanced lung cancer patients, Chinese medicine (CM) has, in recent years, received increased attentions worldwide. We utilized a bibliometric statistical method based on MEDLINE/GoPubMed to conduct a comprehensive analysis of the current application status of CM in lung cancer, by including annual and accumulated publications, origin distribution of countries and journals, and keywords with a higher frequency score. Then the relevant clinical trials and mechanistic studies were systematically summarized within the field according to research types. We have raised potential problems and provided potentially useful reference information that could guide similar studies in the future. The basic experimental results are highly consistent with clinical trials, leading us to conclude that CM can offer better overall therapeutic benefits when used in combination with routine Western medicine for patients with advanced lung cancer.

Pharmacokinetics of Gefitinib: Roles of Drug Metabolizing Enzymes and Transporters.

Gefitinib (Iressa, AstraZeneca) has been widely used for the treatment of locally advanced or metastatic non-small cell lung cancer. A number of studies have been reported on its pharmacokinetics profiles, especially on the metabolism. In this review, we have comprehensively summarized the pharmacokinetic characteristics of gefitinib: absorption, distribution, metabolism and excretion (ADME). Overall, gefitinib reached the maximum plasma level relatively fast and distributed extensively. It underwent extensive biotransformation and predominantly excreted in feces, with less than 7% in the urine. CYP450 enzymes played critical roles in the process of gefitinib metabolism. The major enzyme involved in the metabolism was CYP3A4, with other CYP450 enzymes playing a secondary role. A high clearance of gefitinib might result in drug resistance by lowering drug concentration. The enhanced efflux and decreased uptake by transporters were important resistance mechanisms. The transporters involved in pharmacokinetics of gefitinib consist of the ATP-binding cassette and the solute carrier superfamily. Understanding the pharmacokinetics property of gefitinib may provide valuable and new information for dealing with drug resistance and making personalized therapy regarding their interindividual variability.