CXCL5 knockdown attenuated gemcitabine resistance of pancreatic cancer through regulation of cancer cells and tumour stroma.

Chemoresistance is one of the major causes to the poor prognosis of pancreatic cancer (PC). Gemcitabine alone and gemcitabine-based therapies are mostly used for the treatment of PC. Gemcitabine resistance becomes the focus of chemotherapy. C-X-C motif chemokine 5 (CXCL5), a member of the C-X-C chemokine family, acts through C-X-C chemokine receptor type 2 (CXCR2). A high level of CXCL5 is associated with worse prognosis in PC patients and increased suppressive immune cell infiltration. Increased expression of CXCL5 is also found in gemcitabine-treated PC cells. To investigate the role of CXCL5 in PC response to gemcitabine, CXCL5 knockdown (KD) PC cells were generated and its effect on cancer cell response to gemcitabine in vitro and in vivo was studied. The mechanisms involved were also explored by determining the changes in the tumour microenvironment (TME) and protein profile of the CXCL5 KD cells using immune-staining and proteomic analysis. The results showed that CXCL5 expression were increased in all PC cell lines tested and in gemcitabine-resistant tumour tissue, that CXCL5 KD suppressed PC growth and sensitized PC cell response to gemcitabine and that CXCL5 KD stimulated the activation of stromal cells in TME. We conclude that CXCL5 promotes gemcitabine resistance by affecting TME and cancer cells.

CXCL2/CXCR2 axis induces cancer stem cell characteristics in CPT-11-resistant LoVo colon cancer cells via Gαi-2 and Gαq/11.

Cancer stem cells (CSCs) exist in colon cancer and exhibit characteristics of stem cells which are due to lineages of tissues where they arise. Epithelial to mesenchymal transition (EMT)-undergoing cancer cells display CSC properties and therapeutic resistance. Cancer and stromal cells comprise of a tumor microenvironment. One way the two populations communicate with each other is to secret CXC ligands (CXCLs). CXCLs are capable of causing chemotaxis of specific types of stromal cells and control angiogenesis. Double immunofluorescence, western blot analysis, and colony-formation assay were carried out to compare parental and CPT-11-resistant LoVo cells. CPT-11-R LoVo colon cancer cells showed increased expression of CXCL1, CXCL2, CXCL3, and CXCL8. They displayed significantly increased intracellular protein levels of CXCL2 and CXCR2. CPT-11-R LoVo cells showed significantly elevated expression in aldehyde dehydrogenase 1 (ALDH1), cluster of differentiation 24 (CD24), cluster of differentiation 44 (CD44), and epithelial cell adhesion molecule (EpCAM). CXCL2 knockdown by short hairpin RNA resulted in reduced expression of CSC proteins, cyclins, EMT markers, G proteins, and matrix metalloproteinases (MMPs). Finally, Gαi-2 was found to promote expression of CSC genes and tumorigenesis which were more apparent in the resistant cells. In addition, Gαq/11 showed a similar pattern with exceptions of EpCAM and MMP9. Therefore, CXCL2-CXCR2 axis mediates through Gαi-2 and Gαq/11 to promote tumorigenesis and contributes to CSC properties of CPT-11-R LoVo cells.

Functions of the CXC ligand family in the pancreatic tumor microenvironment.

Therapeutic resistance is the major contributor to the poor prognosis of and low survival from pancreatic cancer (PC). Cancer progression is a complex process reliant on interactions between the tumor and the tumor microenvironment (TME). Members of the CXCL family of chemokines are present in the pancreatic TME and seem to play a vital role in regulating PC progression. As pancreatic tumors interact with the TME and with PC stem cells (CSCs), determining the roles of specific members of the CXCL family is vital to the development of improved therapies. This review highlights the roles of selected CXCLs in the interactions between pancreatic tumor and its stroma, and in CSC phenotypes, which can be used to identify potential treatment targets.

Tanshinone IIA Inhibits ß-Catenin Nuclear Translocation and IGF-2R Activation via Estrogen Receptors to Suppress Angiotensin II-Induced H9c2 Cardiomyoblast Cell Apoptosis.

Cardiomyopathy involves changes in the myocardial ultra-structure, hypertrophy, apoptosis, fibrosis and inflammation. Angiotensin II (AngII) stimulates the expression of insulin like-growth factors (IGF-2) and IGF-2 receptor (IGF-2R) in H9c2 cardiomyoblasts and subsequently leads to apoptosis. Estrogen receptors protect cardiomyocytes from apoptosis and fibrosis. Tanshinone IIA (TSN), a main active ingredient from Danshen, has been shown to protect cardiomyocytes from death caused by different stress signals. Estrogen receptor α (ER) is required for the rapid activation of the IGF-1R signaling cascade. This study aimed to investigate whether TSN protected H9c2 cardiomyocytes from AngII-induced activation of IGF-2R pathway and hypertrophy via ERs. We found that AngII caused the reduction in IGF-1R phosphorylation and the elevation of ß-catenin and IGF-2R levels. This was reversed by increasing doses of TSN and of caspase-3 and ERK1/2 phosphorylation mediated by ERs. The phytoestrogen significantly attenuated AngII-induced apoptosis and suppressed the subsequent cardiac remodeling effect. Therefore, TSN reduced the AngII-induced activation of ß-catenin and IGF-2R pathways, apoptosis and cardiac remodeling via ERs in H9c2 cardiomyoblasts.

Tanshinone-induced ERs suppresses IGFII activation to alleviate Ang II-mediated cardiac hypertrophy.

Cardiomyopathy involves changes in myocardial ultrastructure and cardiac hypertrophy. Angiotensin II (AngII) has previously been shown to stimulate the expression of IGF-2 and IGF-2R in H9c2 cardiomyoblasts and increase of blood pressure, and cardiac hypertrophy. Estrogen receptors (ERs) exert protective effects, such as anti-hypertrophy in cadiomyocytes. Tanshinone IIA (TSN), a main active ingredient from a Chinese medical herb, Salvia miltiorrhiza Bunge (Danshen), was shown to protect cardiomyocytes hypertrophy by different stress signals. We aimed to investigate whether TSN protected H9c2 cardiomyocytes from AngII-induced activation of IGF-2R pathway and hypertrophy by mediating through ERs. AngII resulted in H9c2 cardiomyoblast hypertrophy and increased inflammatory molecular markers. These were down-regulated by TSN via estrogen receptors. AngII resulted in elevation in MAPKs, IGF-2R and hypertrophic protein markers. These, again, were reduced by addition of the phytoestrogen with activation of ERs. Finally, AngII induced phosphorylation of heat shock factor-1 (HSF1) and decreased sirtuin-1 (SIRT1). In addition, AngII also caused an increase in distribution of IGF-2R molecules on cell membrane. In contrast, TSN reduced HSF1 phosphorylation and cell surface IGF-2R while elevating SIRT1 via ERs. TSN was capable of attenuating AngII-induced IGF-2R pathway and hypertrophy through ERs in H9c2 cardiomyoblast cells.

Inhibition of NF-κB and metastasis in irinotecan (CPT-11)-resistant LoVo colon cancer cells by thymoquinone via JNK and p38.

Clinically used chemotherapeutics can effectively eliminate most tumor cells. However, they cause unwanted side effects and result in chemoresistance. To overcome such problems, phytochemicals are now used to treat cancers by means of targeted therapy. Thymoquinone (TQ) is used to treat different cancers (including colon cancer) and is an NF-κB inhibitor. Irinotecan resistant (CPT-11-R) LoVo colon cancer cell line was previous constructed by step-wise CPT-11 challenges to un-treated parental LoVo cells and expresses EGFR/IKKα/ß/NF-κB pathway. TQ resulted in reduced total and phosphorylation of IKKα/ß and NF-κB and decreased metastasis in CPT-11-R cells. TQ not only reduced activity of ERK1/2 and PI3K but also activated JNK and p38. Furthermore, TQ was also found to suppress metastasis through activation of JNK and p38. Therefore, TQ suppressed metastasis through NF-κB inhibition and activation of JNK and p38 in CPT-11-R LoVo colon cancer cells. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 669-678, 2017.

Thymoquinone induces caspase-independent, autophagic cell death in CPT-11-resistant lovo colon cancer via mitochondrial dysfunction and activation of JNK and p38.

Chemotherapy causes unwanted side effects and chemoresistance, limiting its effectiveness. Therefore, phytochemicals are now used as alternative treatments. Thymoquinone (TQ) is used to treat different cancers, including colon cancer. The irinotecan-resistant (CPT-11-R) LoVo colon cancer cell line was previously constructed by stepwise CPT-11 challenges to untreated parental LoVo cells. TQ dose-dependently increased the total cell death index and activated apoptosis at 2 µM, which then diminished at increasing doses. The possibility of autophagic cell death was then investigated. TQ caused mitochondrial outer membrane permeability (MOMP) and activated autophagic cell death. JNK and p38 inhibitors (SP600125 and SB203580, respectively) reversed TQ autophagic cell death. TQ was also found to activate apoptosis before autophagy, and the direction of cell death was switched toward autophagic cell death at initiation of autophagosome formation. Therefore, TQ resulted in caspase-independent, autophagic cell death via MOMP and activation of JNK and p38 in CPT-11-R LoVo colon cancer cells.

Resistance to irinotecan (CPT-11) activates epidermal growth factor receptor/nuclear factor kappa B and increases cellular metastasis and autophagy in LoVo colon cancer cells.

Chemotherapy is usually applied to treat colon cancer but leads to chemoresistance, and increased metastasis and invasion. The main focus of this study is to observe effects of resistance to irinotecan (CPT-11) on metastasis, invasion and autophagy in CPT-11 resistant (CPT-11-R) LoVo colon cancer cells. CPT-11, a topoisomerase I inhibitor and a first-line chemotherapeutic drug, is used to treat colon cancer. CPT-11-R cells were constructed in a step-wise fashion with increasing CPT-11 doses. The CPT-11-R strain had a significantly lower expression of Wnt/ß-catenin pathway, but induced an EGFR/IKKα/ß/NF-κB pathway with elevated cell cycle, metastasis and basal autophagy.

Apicidin-resistant HA22T hepatocellular carcinoma cells massively promote pro-survival capability via IGF-IR/PI3K/Akt signaling pathway activation.

Despite rapid advances in the diagnostic and surgical procedures, hepatocellular carcinoma (HCC) remains one of the most difficult human malignancies to treat. This may be due to the chemoresistant behaviors of HCC. It is believed that acquired resistance could be overcome and improve the overall survival of HCC patients by understanding the mechanisms of chemoresistance in HCC. A stable HA22T cancer line, which is chronically resistant to a histone deacetylase inhibitor, was established. After comparing the molecular mechanism of apicidin-R HA22T cells to parental ones by Western blotting, cell cycle-regulated proteins did not change in apicidin-R cells, but apicidin-R cells were more proliferative and had higher tumor growth (wound-healing assay and nude mice xenograft model). Moreover, apicidin-R cells displayed increased levels of p-IGF-IR, p-PI3K, p-Akt, Bcl-xL, and Bcl-2 but also significantly inhibited the tumor suppressor PTEN protein and apoptotic pathways when compared to the parental strain. Therefore, the highly proliferative effect of apicidin-R HA22T cells was blocked by Akt knockdown. For all these findings, we believe that novel strategies to attenuate IGF-IR/PI3K/Akt signaling could overcome chemoresistance toward the improvement of overall survival of HCC patients.

Dung-Shen Downregulates the Synergistic Apoptotic Effects of Angiotensin II Plus Leu 27-IGF II on Cardiomyoblasts.

BACKGROUND: Insulin growth factor II (IGFII) is expressed after ischemic stress in pig hearts and after myocardial infarction in humans. However, its receptor (IGFIIR) cannot be found in normal adult hearts. Moreover, a mouse IGFII overexpression model showed a heart and kidney hypertrophy phenomenon similar to Beckwith-Wiedemann syndrome in humans. The previous studies from our lab showed that an increase in AngII in H9c2 cells causes an elevation in IGFII and IGFIIR through MEK and JNK activation, leading to a rise in intracellular Ca(2+) ions, activation of calcineurin by PLC-ß3 via Gαq, insertion into mitochondrial membranes of BAD, and apoptosis via activation of caspases 9 and 3. Codonopsis pilosula (Dung-shen) has various uses in traditional Chinese medicine, including lowering blood pressure, and increasing red and white blood cell counts. METHODS: The purpose of our study is to investigate whether the addition of C. pilosula will attenuate the AngII plus Leu27-IGFII-induced apoptosis in H9c2 cardiomyoblast cells. RESULTS: From MTT [3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-tetrazolium bromide] results, it was revealed that AngII plus Leu(27)-IGFII significantly reduced cell viability, which was reversed by C. pilosula. Additionally, C. pilosula also reversed apoptosis (TUNEL staining) increased by AngII plus Leu27-IGFII. Up-regulation of caspase 3 by AngII plus Leu27-IGFII was attenuated by C. pilosula treatment, as shown in western blotting assay and immunofluorescence microscopy results. CONCLUSIONS: C. pilosula is able to suppress the apoptotic pathway enhanced by AngII plus Leu27-IGFII in myocardial cells. KEY WORDS: Angiotensin II; Apoptosis; Codonopsis pilosula; Leucine27-insulin like growth factor II; Mitochondrial outer membrane permeability.

Dung-shen (Codonopsis pilosula) attenuated the cardiac-impaired insulin-like growth factor II receptor pathway on myocardial cells.

Previous studies from our lab showed that increase in AngII in H9c2 cells causes elevated IGFII and IGFIIR through MEK and JNK, leading to rise in intracellular calcium, calcineurin activation by PLC-ß3 via Gαq, insertion into mitochondrial membranes of Bad, and apoptosis via caspases 9 and 3. Codonopsis pilosula is traditionally used to lower blood pressure. The purpose of our study is to investigate if C. pilosula attenuates AngII plus Leu(27)-IGFII-induced calcium influx and apoptosis in H9c2 cardiomyoblasts. C. pilosula significantly attenuated AngII induced IGFIIR promoter activity. Leu(27)-IGFII was applied to enhance the AngII effect. C. pilosula also reversed Ca(2+) influx, MOMP and apoptosis increased by AngII plus Leu(27)-IGFII. Molecular markers in IGFIIR apoptotic pathway (IGFIIR, calcineurin, etc.) and IGFIIR-Gαq association were downregulated by C. pilosula. However, p-Bad(Ser136) and Bcl-2 were increased. Therefore, C. pilosula suppresses AngII plus Leu(27)-IGFII-induced IGFII/IGFIIR pathway in myocardial cells.

Activation of snail and EMT-like signaling via the IKKαß/NF-κB pathway in Apicidin-resistant HA22T hepatocellular carcinoma cells.

The molecular and phenotypic associations between chemo- or radio-resistance and the acquisition of epithelial-mesenchymal transition (EMT)-like phenotype are tightly related in cancer cells. Wnt/ß- catenin and NF-κB signaling pathways play crucial roles in EMT induction. Apicidin-resistant (Apicidin- R) HA22T cells are known to activate the Wnt/ß-catenin signaling pathway and MMP-2 expression via the IGF-IR/PI3K/Akt signaling pathway to enhance metastatic effects of cancer cells. In this study, we further investigated if Apicidin-R HA22T cells actually underwent EMT. In Apicidin-R HA22T cells, E-cadherin protein level was reduced but Vimentin, Snail and Twist were significantly activated. Activation of p-IKKαß and p-IκBα was also observed in Apicidin-R HA22T cells. Apicidin-R HA22T cells displayed even higher NF-κB nuclear accumulation. Snail was enhanced but GSK3-ß was reduced. However, unphosphorylated GSK3-ß protein level was totally reversed when the Snail-specific siRNA was applied in a knockdown experiment. Taken together, Apicidin-R HA22T cells could potentiate aggressive metastasis behavior due to up-regulation of Snail expression and promoted EMT effects via the IKKαß/NF-κB pathway. In addition, Snail might decrease the GSK3-ß level resulting in extraordinarily activation of Wnt/ß-catenin signaling pathway.