Tea-Derived Polyphenols Enhance Drought Resistance of Tea Plants (Camellia sinensis) by Alleviating Jasmonate-Isoleucine Pathway and Flavonoid Metabolism Flow.

Extreme drought weather has occurred frequently in recent years, resulting in serious yield loss in tea plantations. The study of drought in tea plantations is becoming more and more intensive, but there are fewer studies on drought-resistant measures applied in actual production. Therefore, in this study, we investigated the effect of exogenous tea polyphenols on the drought resistance of tea plant by pouring 100 mg·L-1 of exogenous tea polyphenols into the root under drought. The exogenous tea polyphenols were able to promote the closure of stomata and reduce water loss from leaves under drought stress. Drought-induced malondialdehyde (MDA) accumulation in tea leaves and roots was also significantly reduced by exogenous tea polyphenols. Combined transcriptomic and metabolomic analyses showed that exogenous tea polyphenols regulated the abnormal responses of photosynthetic and energy metabolism in leaves under drought conditions and alleviated sphingolipid metabolism, arginine metabolism, and glutathione metabolism in the root system, which enhanced the drought resistance of tea seedlings. Exogenous tea polyphenols induced jasmonic acid-isoleucine (JA-ILE) accumulation in the root system, and the jasmonic acid-isoleucine synthetase gene (TEA028623), jasmonic acid ZIM structural domain proteins (JAMs) synthesis genes (novel.22237, TEA001821), and the transcription factor MYC2 (TEA014288, TEA005840) were significantly up-regulated. Meanwhile, the flavonoid metabolic flow was significantly altered in the root; for example, the content of EGCG, ECG, and EGC was significantly increased. Thus, exogenous tea polyphenols enhance the drought resistance of tea plants through multiple pathways.

[Retracted] Inhibition airway remodeling and transforming growth factor­ß1/Smad signaling pathway by astragalus extract in asthmatic mice.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the P­smad2 western blotting data shown in Fig. 7 were strikingly similar to data appearing in different form (namely, the bands appeared in the reverse orientation) in Fig. 4A in another article [Lv Z­D, Na D, Liu F­N, Du Z­M, Sun Z, Li Z, Ma X­Y, Wang Z­N and Xu H­M: Induction of gastric cancer cell adhesion through transforming growth factor­beta1­mediated peritoneal fibrosis. J Exp Clin Cancer Res 29: 139, 2010], which was written by mostly different authors at different research institutes (the author Zheng­Hai Qu did appear as an author on both papers). Owing to the fact that the contentious data in the above article had already been published prior to its submission to International Journal of Molecular Medicine, and due to a lack of overall confidence in the presented data, the Editor has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Molecular Medicine 29: 564­568, 2012; DOI: 10.3892/ijmm.2011.868].

Clinicopathological characteristics and prognosis of early-stage HER2 low-expression breast cancer: A single-center retrospective study.

Background: Owing to the emergence of drugs targeting human epidermal growth factor receptor 2 (HER2), remarkable prognostic enhancement has been seen for patients with HER2-positive breast carcinoma. However, anti-HER2 medicines are applicable merely to individuals with HER2-positive tumors, and the benefit for those with low HER2 expression is unclear. The DESTINY-Breast04 phase III and RC48 clinical trial results showed the benefit of antibody-drug couples for low HER2-expressing individuals with breast carcinoma, challenging the traditional dichotomy between HER2-negative and -positive tumors. Hence, the purposes of the present work are to explore the clinicopathological traits and prognostic differences in the HER2-low expression Chinese population with early-stage breast carcinoma. Methods: Data from the database of the Breast Center of the Affiliated Hospital of Qingdao University were collected from January 2008 to December 2017. We screened a total of 4,598 patients, of which 2,837 had HER2-0 tumors and 1,761 had HER2-low tumors. Additionally, clinicopathological characteristics, survival, and prognostic information were obtained. Difference comparisons were made between HER2-0 and HER2-low groups regarding the clinical traits and outcomes. Results: We enrolled 4598 patients, with the HR-positive subjects suffering from HER2-low breast carcinoma higher in proportion than the HR-negative patients. In contrast to HER2-0 tumors, the HER2-low tumors were linked to an older median age at diagnosis, T1 tumors, N1 stage, a higher Ki-67 index, as well as inferior histological grade. Insignificant inter-group difference was noted regarding overall survival (OS), although the HER2-0 group exhibited better disease-free survival (DFS) than the HER2-low group for the entire (P = 0.003), lymph node-negative (P = 0.009) and HR-positive (P = 0.007) populations. According to the multivariate regression finding, low HER2 expression was an inferior DFS prognostic factor in the HER2-negative population with early-stage breast cancer (HR,1.33;95% CI, 1.06-1.66; P = 0.013). Conclusion: The clinical traits of the HER2-low carcinomas differed from those of HER2-0 tumors. Despite the insignificant inter-group difference in OS, the differences in DFS were found for the overall, lymph node-negative and HR-positive subjects, suggesting the possibility of HER2-low as an inferior prognostic factor for disease progression in early-stage breast cancer.

[Retracted] TGF­ß1 induces peritoneal fibrosis by activating the Smad2 pathway in mesothelial cells and promotes peritoneal carcinomatosis.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that the fluorescence microscopy data shown in Fig. 6A and B were strikingly similar to data appearing in different form in Fig. 7 in a previously published paper [Lv Z­D, Na D, Liu F­N, Du Z­M, Sun Z, Li Z, Ma X­Y, Wang Z­N and Xu H­M: Induction of gastric cancer cell adhesion through transforming growth factor­beta1­mediated peritoneal fibrosis. J Exp Clin Cancer Res 29: 139, 2010], which featured some of the same authors, although the data were shown to portray results obtained under different experimental conditions. Furthermore, the data in Fig. 7A for the 'TGF­ß1' and the 'TGF­ß1 + siRNAcon' experiments contained an overlapping section, such that these data appeared to have been derived from the same original source, even though they were intended to show the results from differently performed experiments. Owing to the fact that the contentious data in the above article had already been published prior to its submission to International Journal of Molecular Medicine, and due to a lack of overall confidence in the presented data, the Editor has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [International Journal of Molecular Medicine 29: 373­379, 2012; DOI: 10.3892/ijmm.2011.852].

Predicting Pathological Complete Response in Breast Cancer After Two Cycles of Neoadjuvant Chemotherapy by Tumor Reduction Rate: A Retrospective Case-Control Study.

PURPOSE: We aimed to identify effectiveness-associated indicators and evaluate the optimal tumor reduction rate (TRR) after two cycles of neoadjuvant chemotherapy (NAC) in patients with invasive breast cancer. METHODS: This retrospective case-control study included patients who underwent at least four cycles of NAC at the Department of Breast Surgery between February 2013 and February 2020. A regression nomogram model for predicting pathological responses was constructed based on potential indicators. RESULTS: A total of 784 patients were included, of whom 170 (21.68%) reported pathological complete response (pCR) after NAC and 614 (78.32%) had residual invasive tumors. The clinical T stage, clinical N stage, molecular subtype, and TRR were identified as independent predictors of pCR. Patients with a TRR > 35% were more likely to achieve pCR (odds ratio, 5.396; 95% confidence interval [CI], 3.299-8.825). The receiver operating characteristic (ROC) curve was plotted using the probability value, and the area under the ROC curve was 0.892 (95% CI, 0.863-0.922). CONCLUSION: TRR > 35% is predictive of pCR after two cycles of NAC, and an early evaluation model using a nomogram based on five indicators, age, clinical T stage, clinical N stage, molecular subtype, and TRR, is applicable in patients with invasive breast cancer.

Impact of hormone receptor, HER2, and Ki-67 status conversions on survival after neoadjuvant chemotherapy in breast cancer patients: a retrospective study.

Background: The discordance of estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2), and Ki-67 cell nuclear proliferation antigen status in patients with locally advanced breast cancer pre- and post-neoadjuvant chemotherapy (NAC) is quite common. This study aimed to assess the frequency of changes in receptor status after NAC in patients with invasive ductal breast cancer and the prognostic impact of such changes. Methods: The study comprised 670 patients who were diagnosed with invasive ductal breast carcinoma and treated with both NAC and surgery from 2012-2017. Hormone receptor (HR; including ER and PR), HER2, and Ki-67 status was assessed before NAC and in residual invasive tumor cells of the surgical specimens. The prognostic impact of receptor conversions in breast cancer patients treated with NAC was evaluated in this retrospective study. Results: The conversion of ER was related to overall survival (OS; P=0.008) and disease-free survival (DFS; P=0.004). Patients whose ER status was always positive had the best prognosis, and those who were always negative had the worst prognosis. Similar results were also found for PR status, as the conversion of PR status was also related to OS (P<0.001) and DFS (P<0.001). At the same time, the conversion of Ki-67 status was related to OS (P=0.042) and DFS (P=0.037), and patients whose Ki-67 status was ≤20% persistently after NAC had the best survival among the 4 groups, while those whose Ki-67 status changed from ≤20% to >20% after NAC had the worst survival. Nevertheless, there was no statistical significance in the conversion of HER2 status. In multivariate Cox regression analyses, PR conversion and post-neoadjuvant pathological lymph node stage (ypN) were independent prognostic factors for DFS (P=0.008, <0.001) and OS (P=0.002, <0.001). Conclusions: Changes in receptor status between pre-treatment and residual disease after NAC are common. Moreover, these alterations have an impact on the survival outcome of invasive ductal breast cancer patients. Thus, receptor status should be re-evaluated routinely before and after NAC to guide individualized treatment.

Targeting PGC1α to wrestle cancer: a compelling therapeutic opportunity.

Metabolic adaptation is an emerging hallmark of cancer, as it provides tumor cells sufficient energy and metabolic intermediates. Although tumor cells are believed to highly rely on Warburg effect to satisfy their energy demand, more studies have pointed out that various types of tumor cells are highly dependent on oxidative phosphorylation to drive the tumorigenesis. Peroxisome proliferator-activated receptor-c coactivator 1α (PGC1α), the crucial member of PGC1 family, is aberrantly expressed in several cancer types, implicating its role in tumor proliferation, migration, invasion, metastasis, and chemoresistance. Numerous studies have reported that PGC1α participates in the regulation of tumor development by altering the transcriptional programs as well as the metabolic phenotypes. Thus, PGC1α-targeted therapy is therapeutically exploitable to target the metabolic vulnerabilities in tumor cells. This review mainly focuses on the current underlying mechanisms for its roles in regulating metabolic adaptation of tumor cells and its upstream regulators; how PGC1α participates in the regulation of the tumor proliferation, migration, invasion, metastasis, therapy resistance; and the feasibility of PGC1α-targeted therapy for cancer treatment.

OLR1 is a prognostic factor and correlated with immune infiltration in breast cancer.

Oxidized low-density lipoprotein receptor 1 (OLR1), a key receptor for oxidized low-density lipoprotein (ox-LDL), plays a crucial role in cancer and inflammatory disease. However, the correlation between OLR1 expression and immune infiltration in breast cancer (BC) remain unclear. In this study, we comprehensively analyzed the expression level of OLR1 in BC tissues and explore the prognostic importance of OLR1 using quantitative real-time PCR, immunohistochemical analysis and different databases. The significantly enriched KEGG and GO pathways were used to identify the potential biological function of OLR1 via LinkedOmics analysis. Furthermore, we detected the correlation between OLR1 expression and a variety of immune infiltrating cells via Tumor Immune Estimation Resource database and GEPIA database. Our study revealed that OLR1 upregulation was observed in BC tissues and correlated with worse clinical outcomes and advanced clinicopathological factors. Meanwhile, OLR1 regulated various immunity-related pathways, especially the polarization of macrophages. Immunohistochemical analysis further confirmed the significant correlation between OLR1 expression and tumor infiltration of M2 macrophages as well as tumor-associated macrophages. OLR1 upregulation indicated poor prognosis in BC, possibly through inducing macrophage polarization and triggering immune evasion. Collectively, OLR1 may represent a potential therapeutic target for BC tailored therapy.

Research progress on the response of tea catechins to drought stress.

Drought stress (DS) is the most important abiotic stress affecting yield and quality of tea worldwide. DS causes oxidative stress to cells due to the accumulation of reactive oxygen species (ROS). As non-enzymatic antioxidants, tea catechins can scavenge excess ROS in response to DS. Further, catechin accumulation contributes to the formation of oxidative polymerization products (e.g. theaflavins and thearubigins) that improve the quality of black tea. However, there are no systematic reports on the response of tea catechins to DS. First, we reviewed the available literature on the response of tea plants to DS. Second, we summarized the current knowledge of ROS production in tea leaves under DS and typical antioxidant response mechanisms. Third, we conducted a detailed review of the changes in catechin levels in tea under different drought conditions. We found that the total amounts of catechin and o-quinone increased under DS conditions. We propose that the possible mechanisms underlying tea catechin accumulation under DS conditions include (i) autotrophic formation of o-quinone, (ii) polymerization of proanthocyanidins that directly scavenge excess ROS, and (iii) formation of metal ion complexes and by influencing the antioxidant systems that indirectly eliminate excess ROS. Finally, we discuss ways of potentially improving black tea quality using drought before picking in the summer/fall dry season. In summary, we mainly discuss the antioxidant mechanisms of tea catechins under DS and the possibility of using drought to improve black tea quality. Our review provides a theoretical basis for the production of high-quality black tea under DS conditions. © 2021 Society of Chemical Industry.

Tumor-associated macrophages-mediated CXCL8 infiltration enhances breast cancer metastasis: Suppression by Danirixin.

Breast cancer is the most frequent cancer among females and the second most common cause of cancer deaths worldwide. Tumor-associated macrophages (TAMs) are the most abundant immune cell population in the tumor microenvironment, including breast cancer. Breast cancer stem cells (BCSCs) play an important role in regulating breast cancer growth and metastasis, which still remains an obstacle for successful treatment of breast cancer and requires further investigation, as well as the potential therapeutic strategies. Cytokine array validated that C-X-C motif chemokine ligand 8 (CXCL8) is a pivotal chemokine secreted by TAMs, and CXCL8 could enhance breast cancer migration, invasion ability, and epithelial-mesenchymal transition (EMT) in both animal and human breast cancer. In this study, the clinical data firstly indicated that high CXCL8 expression was significantly associated with metastasis and tumor growth in breast cancer patients. Then, we showed that TAMs-released CXCL8 could markedly elevate the migration, invasion and EMT events in breast cancer cells, as well as the self-renewal of BCSCs in vitro. These processes were markedly abrogated by the treatment of Danirixin, a reversible and selective antagonist of CXC chemokine receptor 2 (CXCR2). Consistently, the in vivo analysis confirmed that CXCL8 suppression using Danirixin effectively reduced the tumor growth, lung metastasis and repressed the self-renewal of BCSCs. Collectively, TAMs/CXCL8 could enhance BCSCs self-renewal and breast cancer metastasis, and these effects could be markedly abolished by Danirixin treatment, suppressing breast cancer progression consequently. Therefore, Danirixin could be considered as a novel and effective therapeutic strategy for breast cancer treatment without obvious toxicity to major organs.

Quantification of Ki67 Change as a Valid Prognostic Indicator of Luminal B Type Breast Cancer After Neoadjuvant Therapy.

Introduction: Ki67 value and its variation before and after neoadjuvant chemotherapy are commonly tested in relation to breast cancer patient prognosis. This study aims to quantify the extent of changes in Ki67 proliferation pre- and post-neoadjuvant chemotherapy, confirm an optimal cut-off point, and evaluate its potential value for predicting survival outcomes in patients with different molecular subtypes of breast cancer. Methods: This retrospective real-world study recruited 828 patients at the Department of Breast Surgery of the First Affiliated Hospital of China Medical University and the Cancer Hospital of China Medical University from Jan 2014 to Nov 2020. Patient demographic features and disease pathology characteristics were recorded, and biomarkers were verified through immunohistochemistry. Various statistical methods were used to validate the relationships between different characteristics and survival outcomes irrespective of disease-free and overall survival. Results: Among 828 patients, statistically significant effects between pathological complete response and survival outcome were found in both HER2-enriched and triple-negative breast cancer (p < 0.05) but not in Luminal breast cancer (p > 0.05). Evident decrease of Ki67 was confirmed after neoadjuvant chemotherapy. To quantify the extent of Ki67 changes between pre- and post-NAC timepoints, we adopted a computational equation termed ΔKi67% for research. We found the optimal cut-off value to be "ΔKi67% = -63%" via the operating characteristic curve, defining ΔKi67% ≤ -63% as positive status and ΔKi67% > -63% as negative status. Patients with positive ΔKi67% status were 37.1% of the entire cohort. Additionally, 4.7, 39.9, 34.5 and 39.6% of patients with Luminal A, Luminal B, HER2-enriched and triple negative breast cancer were also validated with positive ΔKi67% status. The statistically significant differences between ΔKi67% status and prognostic outcomes were confirmed by univariate and multivariate analysis in Luminal B (univariate and multivariate analysis: p < 0.05) and triple negative breast cancer (univariate and multivariate analysis: p < 0.05). We proved ΔKi67% as a statistically significant independent prognostic factor irrespective of disease-free or overall survival among patients with Luminal B and triple-negative breast cancer. Conclusions: ΔKi67% can aid in predicting patient prognostic outcome, provide a measurement of NAC efficacy, and assist in further clinical decisions, especially for patients with Luminal B breast cancer.

Efficacy and Safety of Albumin-Bound Paclitaxel Compared to Docetaxel as Neoadjuvant Chemotherapy for HER2-Negative Breast Cancer.

BACKGROUND: Nanoparticle albumin-bound paclitaxel (nab-paclitaxel) as neoadjuvant chemotherapy (NAC) for breast cancer remains controversial. We conducted a retrospective study to compare the efficacy and safety of nab-paclitaxel with those of docetaxel as neoadjuvant regimens for HER2-negative breast cancer. METHODS: In this retrospective analysis, a total of 159 HER2-negative breast cancer patients who had undergone operation after NAC were consecutively analyzed from May 2016 to April 2018. Patients were classified into the nab-paclitaxel group (n = 79, nab-paclitaxel 260 mg/m2, epirubicin 75 mg/m2, and cyclophosphamide 500 mg/m2) and the docetaxel group (n = 80, docetaxel 75 mg/m2, epirubicin 75 mg/m2, and cyclophosphamide 500 mg/m2) according to the drug they received for neoadjuvant treatment. The efficacy and adverse events were evaluated in the two groups. RESULTS: The pathological complete response (pCR)(ypT0/isN0) rate was significantly higher in the nab-paclitaxel group than in the docetaxel group (36.71% vs 20.00%; P = 0.031). The multivariate analysis revealed that therapeutic drugs, lymph node status, and tumor subtype were the most significant factor influencing treatment outcome. At a median follow-up of 47 months, disease-free survival (DFS) was not significantly different in those assigned to nab-paclitaxel compared with docetaxel (82.28% vs 76.25%; P = 0.331). The incidence of peripheral sensory neuropathy in the nab-paclitaxel group was higher than that in the docetaxel group (60.76% vs 36.25%; P = 0.008), while the incidence of arthralgia was observed more frequently in the docetaxel group (57.50% vs 39.97%; P = 0.047). CONCLUSIONS: Compared with docetaxel, nab-paclitaxel achieved a higher pCR rate, especially those patients with triple-negative breast cancer or lymph node negative breast cancer. However, there was no significant difference in DFS between the two groups. This study provides a valuable reference for the management of patients with HER2-negative breast cancer.

Survival strategies based on the hydraulic vulnerability segmentation hypothesis, for the tea plant [Camellia sinensis(L.) O. Kuntze] in long-term drought stress condition.

Tea plants are important economic perennial crops that can be negatively impacted by drought stress (DS). However, their survival strategies in long-term DS conditions and the accumulation and influence of metabolites and mineral elements (MEs) in their organs, when facing hydraulic vulnerability segmentation, require further investigation. The MEs and metabolites in the leaf, stem, and root after long-term DS (20 d) were examined here, using inductively coupled plasma optical emission spectrometry (ICP-OES) and liquid chromatograph-mass spectrometry (LC-MS). The accumulation patterns of 116 differentially accumulated metabolites (DAMs) and nine MEs were considerably affected in all organs. The concentration of all MEs varied significantly in at least one organ, while the K and Ca levels were markedly altered in all three. Most DAM levels increased in the stem but decreased in the root and leaf, implying that vulnerability segmentation may occur with long-term DS. The typical nitrogen- and carbon-compound levels similarly increased in the stem and decreased in the leaf and root, as the plant might respond to long-term DS by stabilizing respiration, promoting nitrogen recycling, and free radical scavenging. Correlation analysis showed several possible DAM-ME interactions and an association between Mn and flavonoids. Thus, survival strategies under long-term DS included sacrificing distal/vulnerable organs and accumulating function-specialized metabolites and MEs to mitigate drought-induced oxidative damage. This is the first study that reports substance fluctuations after long-term DS in different organs of plants, and highlights the need to use whole plants to fully comprehend stress response strategies.

Physiological and biochemical responses of tea seedlings (Camellia sinensis) to simulated acid rain conditions.

Tea (Camellia sinensis), widely planted in the south of China, and often exposed to acid rain. However, research concerning the impacts of acid rain on physiology and biochemistry of tea plants is still scarce. In this study, we investigated the influence of simulated acid rain (SAR) on plant height, root length, photosynthetic pigment, Fv/Fm, proline, malondialdehyde, antioxidant enzyme activity, total nitrogen, caffeine, catechins, and free amino acids. Our results showed that SAR at pH 4.5 did not hinder plant development because growth characteristics, photosynthesis, and ascorbate peroxidase and catalase activities did not decrease at this pH compared to those at the other investigated pH values. However, at pH 3.5 and pH 2.5, the activities of antioxidase and concentrations of malondialdehyde and proline increased significantly in response to the decrease of photosynthetic pigments and Fv/Fm. In addition, the increase in acidity increased total nitrogen, certain amino acid content (theanine, cysteine), and decreased catechin and caffeine contents, resulting in an imbalance of the carbon and nitrogen metabolisms. Our results indicated that SAR at pH 3.5 and pH 2.5 could restrict photosynthesis and the antioxidant defense system, causing metabolic disorders and ultimately affecting plant development and growth, but SAR at pH 4.5 had no toxic effects on tea seedlings when no other stress factors are involved.

MiR-204-5p Inhibits Transforming Growth Factor-ß1-Induced Proliferation and Extracellular Matrix Production of Airway Smooth Muscle Cells by Regulating Six1 in Asthma.

BACKGROUND: Transforming growth factor-ß1 (TGF-ß1)-in-duced proliferation of airway smooth muscle cells plays critical roles in the development of airway remodeling. Six1 (sine oculis homeobox homolog 1) has been demonstrated to be involved in airway inflammation and remodeling in asthmatic mice. OBJECTIVES: The aim of this work was to investigate the potential role of miR-204-5p in the proliferation and extracellular matrix (ECM) production of airway smooth muscle cells in asthma. METHODS: Real-time PCR was used to measure the expression of miR-204-5p in asthmatic airway smooth muscle cells. Cell viability and apoptosis were detected to evaluate the effect of miR-204-5p on airway smooth muscle cells. Dual-luciferase reporter experiments were applied to identify the target genes of miR-204-5p. RESULTS: MiR-204-5p was downregulated notably in asthmatic airway smooth muscle cells as well as cells stimulated with TGF-ß1. Overexpression of miR-204-5p markedly suppressed the TGF-ß1-induced proliferation of airway smooth muscle cells and the deposition of ECM, whereas the inhibition of miR-204-5p significantly enhanced the proliferation of airway smooth muscle cells and upregulated the level of fibronectin and collagen III. Furthermore, subsequent analyses demonstrated that Six1 was a direct target of miR-204-5p, and Western blot further indicated that miR-204-5p negatively regulated the expression of Six1. Most importantly, the restoration of Six1 expression reversed the inhibitory effect of miR-204-5p on TGF-ß1-induced proliferation and ECM production. CONCLUSIONS: MiR-204-5p inhibits TGF-ß1-in-duced proliferation and ECM production of airway smooth muscle cells by regulating Six1, identifying a potential therapeutic target for preventing airway remodeling in asthma.

miR-135b promotes proliferation and metastasis by targeting APC in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype. The aim of our study was to investigate the functional role of microRNA-135b (miR-135b) in TNBC. A real-time polymerase chain reaction assay was used to quantify miR-135b expression levels in 90 paired TNBC tissue and adjacent normal tissue samples. Wound-healing and transwell assays were performed to evaluate the effects of miR-135b expression on the migration and invasion of TNBC cells. Luciferase reporter and western blot analyses were used to verify whether the mRNA encoding APC is a major target of miR-135b. In the current study, we found that miR-135b was highly expressed in TNBC tissue and cells, and the expression levels were correlated with lymph node status and TNM stage. In TNBC cells, the ectopic expression of miR-135b promoted cell proliferation and invasion in vitro. In addition, our study proved that the overexpression of miR-135b significantly suppressed APC expression by targeting the 3'-untranslated region of APC, whereas enhanced APC expression could partially abrogate the miR-135b-mediated promotion of carcinogenic traits in TNBC cells. Taken together, our study demonstrated that miR-135b expression promoted the proliferation and invasion of TNBC by downregulating APC expression, indicating that miR-135b may serve as a promising target for the treatment of TNBC patients.

p53-independent role of MYC mutant T58A in the proliferation and apoptosis of breast cancer cells.

Myc proto-oncogene (MYC) is an oncoprotein that promotes proliferation and apoptosis. MYC mutations frequently disrupt the apoptotic processes during tumorigenesis. In the present study, the effects of the MYC point mutation T58A on the progression of a cellular tumor antigen p53 (p53)-/- human breast cancer cell line was analyzed, and the mechanism of p53-independent MYC-induced apoptosis was investigated. HCC1937 cells were transfected with mutant (T58A) or wild-type (WT) MYC using lentiviral vectors. The proliferation of transfected cells was evaluated by colony formation and MTT assays, and apoptosis was analyzed by flow cytometry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays. WT MYC was transfected into HCC1937 cells exhibiting p14/p21 silencing through lentivirus-mediated RNA interference. The expression levels of Bim were detected by reverse transcription-quantitative polymerase chain reaction and western blot analyses. Mutant MYC proteins retained the ability to stimulate the proliferation of HCC1937 cells, although they were defective at promoting apoptosis due to a failure to induce the Bcl-2 homology 3 domain-only protein Bim. When p14 was silenced, the effects of mutant MYC on proliferation and apoptosis were weakened. When p21 was silenced, the effects of mutant MYC were strengthened. Breast cancer-derived T58A MYC mutations are unable to activate Bim due to their failure to regulate p14/p21. It was concluded that mutant MYC was more effective compared with WT MYC at promoting the progression of breast cancer.

DLC-3 suppresses cellular proliferation, migration, and invasion in triple-negative breast cancer by the Wnt/ß-catenin pathway.

Triple-negative breast cancer (TNBC) is the most aggressive breast cancer subtype. Our study investigated the functional role of DLC-3 in TNBC. The expression of DLC-3 was assessed by immunohistochemistry in TNBC to evaluate the clinicopathologic significance of DLC-3. Recombinant lentiviral vectors encoding the DLC-3 gene were constructed for transfection into MDA-MB-231. Real-time qPCR and western blot analysis were employed to evaluate the expression of DLC-3, ß-catenin, GSK-3ß and c-myc in DLC-3-transfected cells. Moreover, cell proliferation assays, cell colony formation assays, and cell migration and invasion assays were performed to elucidate the role of DLC-3 in TNBC development and progression. Our data revealed that DLC-3 was downregulated in TNBC, and its expression level was associated with lymph node status and differentiation grade in breast cancer. Both real-time qPCR and western blot analyses showed that the DLC-3 gene and protein were overexpressed in the DLC-3-transfected MDA-MB-231 cells. In addition, the expression of GSK-3ß was upregulated and the expression of ß-catenin and c-myc gene was downregulated in the DLC-3-transfected cells. Furthermore, DLC-3 overexpression inhibited cell proliferation, colony formation, migration, and invasion in vitro. DLC-3, functioning as a tumor-suppressor gene, inhibits cell growth and invasion in TNBC, possibly through regulation of the Wnt/ß-catenin signaling pathway.