Exosomes Mediate the Production of Oxaliplatin Resistance and Affect Biological Behaviors of Colon Cancer Cell Lines.

BACKGROUND: Colon cancer has high mortality rate which making it one of the leading causes of cancer deaths. Oxaliplatin is a common chemotherapeutic drug, but it has disadvantages such as drug resistance. OBJECTIVE: The purpose of this study is to explore the mechanism of exosomes in the resistance of oxaliplatin and verify whether elemene and STAT3 inhibitors reverse the resistance to oxaliplatin. METHODS: Related cell line models were constructed and the proliferation, migration, invasion, apoptosis and resistance to oxaliplatin were evaluated for all three cells of HCT116/L, sensitive cell HCT116 and HCT116+HCT116/L-exosomes (HCT116-exo). It was to explore probable signaling pathways and mechanisms by Western blotting. RESULTS: HCT116-exo drug-resistant chimeric cells showed greater capacity for proliferation, migration and invasion than HCT116 sensitive cells. After the above cells were treated with oxaliplatin, the apoptosis rate of chimeric drug-resistant cells HCT116-exo and its IC50 increased compared with the sensitive cells HCT116. The proliferation, invasion and migration of cells treated with STAT3 inhibitor or ß-elemene combined with oxaliplatin reduced compared with those treated with oxaliplatin or ß-elemene alone. The STAT3 inhibitor or ß-elemene in combination with oxaliplatin increased the rate of apoptosis relative to oxaliplatin or ß-elemene alone. Drug-resistant cell exosomes could promote the EMT process, related to the participation of FGFR4, SHMT2 and STAT3 inhibitors. CONCLUSION: Drug-resistant cell exosomes could induce resistance, and improve the capacity of colon cancer towards proliferate, invade, migrate and promote the EMT process. The ß-elemene combined with oxaliplatin could reverse the above results which might be related to the STAT3 pathway and EMT pathway in colon cancer.

FGFR4 Gly388Arg Polymorphism Affects the Progression of Gastric Cancer by Activating STAT3 Pathway to Induce Epithelial to Mesenchymal Transition.

PURPOSE: Fibroblast growth factor receptor 4 (FGFR4) plays a critical role in cancer progression involving in tumor proliferation, invasion, and metastasis. This study clarified the role of FGFR4-Arg388 variant in gastric cancer (GC), and more importantly highlighted the possibility of this single nucleotide polymorphism (SNP) as potential therapeutic targets. MATERIALS AND METHODS: FGFR4 polymorphism was characterized in advanced GC patients to perform statistical analysis. FGFR4-dependent signal pathways involving cell proliferation, invasion, migration, and resistance to oxaliplatin (OXA) in accordance with the SNP were also assessed in transfected GC cell lines. RESULTS: Among 102 GC patients, the FGFR4-Arg388 patients showed significantly higher tumor stage (p=0.047) and worse overall survival (p=0.033) than the Gly388 patients. Immunohistochemical results showed that FGFR4-Arg388 patients were more likely to have higher vimentin (p=0.025) and p-STAT3 (p=0.009) expression compared with FGFR4-Gly388 patients. In transfected GC cells, the overexpression of FGFR4-Arg388 variant increased proliferation and invasion of GC cells, increasing resistance of GC cells to OXA compared with cells overexpressing the Gly388 allele. CONCLUSION: The exploration mechanism may be through FGFR4-Arg388/STAT3/epithelial to mesenchymal transition axis regulating pivotal oncogenic properties of GC cells. The FGFR4-Arg388 variant may be a biomarker and a candidate target for adjuvant treatment of GC.

Role of fibroblast growth factor 4 in the growth and metastasis of colorectal cancer.

The role of fibroblast growth factor receptor 4 (FGFR4) in colorectal cancer (CRC) is poorly characterized. Therefore, the objective of the current study was to investigate the expression levels of FGFR4 in colorectal cancer and its prognostic value, and clarify the role of FGFR4 in the proliferation and metastasis of colorectal cancer cells. Immunohistochemistry was used to detect the association between FGFR4 expression and clinicopathological features in colorectal cancer tissues. The effect of FGFR4 silencing on tumor cell proliferation, cell cycle, apoptosis, migration and invasion was evaluated via lentiviral transfection of the colorectal cancer cell line SW620. Western blot analysis was used to detect the changes of epithelial­mesenchymal transition (EMT) markers, following FGFR4 silencing. FGFR4 is upregulated in CRC tissues compared with normal tissues. Patients with high FGFR4 expression exhibited a lower 5­year survival rate compared with patients with low FGFR4 expression (64 vs. 74%). FGFR4 silencing reduced proliferation, inhibited cell invasion, arrested cells in S phase and promoted apoptosis in colorectal cancer cells. FGFR4 silencing partially reversed EMT progression and FGFR4 this effect was enhanced in the presence of XAV939 (a ß­catenin inhibitor). The current data suggest that FGFR4 may be associated with prognosis in patients with colorectal cancer. In vitro functional tests revealed that FGFR4 may represent an effective therapeutic target for colorectal cancer. FGFR4 may also regulate EMT via the Wnt/ß­catenin pathway.

Combination of FGFR4 inhibitor Blu9931 and 5-fluorouracil effects on the biological characteristics of colorectal cancer cells.

The aim of this study was to explore the effects of single agent treatments and combination of Blu9931 and 5-fluorouracil (5-FU) on the biological characteristics of colorectal cancer cells and its mechanism. Blu9931 is the first selective small molecule inhibitor of the fibroblast growth factor receptor 4 (FGFR4) and exquisitely selective for FGFR4 versus other FGFR family members and all other kinases. The colorectal cancer cells HCT116 and SW620 with high expression of FGFR4 were selected for a series of functional tests including cell viability, cell proliferation, apoptosis and cell cycle detection. Western blotting was used to detect the expression of related molecules including signal pathway (STAT3), apoptosis (cleaved caspase­3), cell cycle (cyclin D1 and P27kip1) and epithelial-mesenchymal transition (E-cadherin and vimentin) in HCT116 and SW620 cells used as single and combination treatments of 5­FU and Blu9931. The cell viability gradually decreased when the concentration of 5­FU and Blu9931 increased. Blu9931 can inhibit FGFR4 protein expression while 5­FU cannot, as assessed by western blot analysis. The single agent treatment and combinations of 5­FU and Blu9931 arrest cell cycle (P<0.05), increased p27kip1 expression and reduced cyclin D1 expression. The single agent treatment and combinations of 5­FU and Blu9931 inhibited EMT. Furthermore, the combination of 5­FU and Blu9931 has a synergistic effect in reducing colorectal cancer cell proliferation and preventing cell cycle. Taken together, this study provides the first evidence that Blu9931 functions as a FGFR4-selective inhibitor in colorectal cancer (CRC) cells, and Blu9931 may be a new targeted drug.

Silencing of FGFR4 could influence the biological features of gastric cancer cells and its therapeutic value in gastric cancer.

To clarify the role of fibroblast growth factor receptor 4 (FGFR4) in gastric cancer (GC) and explore the therapeutic value of BGJ398 targeted to FGFR4. We constructed lentivirus vectors to stably knockdown FGFR4 expression in GC cells. Function assays in vitro and in vivo, treated with 5-fluorouracil (5-Fu) and BGJ398, were performed to study the change of biological behaviors of GC cells and related mechanism. The proliferation and invasive ability of HGC27 and MKN45 significantly decreased while the apoptosis rate of GC cells obviously increased in shRNA group (P < 0.05). The expressions of Bcl-xl, FLIP, PCNA, vimentin, p-erk, and p-STAT3 significantly reduced while the expressions of caspase-3 and E-cadherin markly enhanced in shRNA group. The proliferation abilities of GC cells were more significantly inhibited by the combination of BGJ398 and 5-Fu in shRNA group (P < 0.05). Compared to negative control (NC), the single and combination of 5-Fu and BGJ398 all significantly increased the apoptosis rate of GC cells, especially in the combination group (P < 0.01). The single and combination of 5-Fu and BGJ398 decreased the expressions of PCNA, Bcl-xl, and FLIP while increased the expression of caspase-3 in GC cells, especially in shRNA groups. Furthermore, knockdown of FGFR4 expression might prevent the growth of GC in vivo. Silencing of FGFR4 expression could weaken the invasive ability, increase the apoptosis rate, and decrease the proliferation ability of GC cells in vitro and in vivo. Furthermore, the combination of 5-Fu and BGJ398 had synergy in inhibiting the proliferation ability and increasing apoptosis rate of GC cells, directing a new target drug in GC.