Gastric adenocarcinoma (GAC), the most common malignancy of the stomach, is the fourth most common and the second cause of cancer-related death worldwide. Although HER family plays a cardinal role in tumorigenesis of GAC, trastuzumab is the only approved anti-HER drug for this malignancy and development of resistance to trastuzumab is inevitable. Additionally, single-targeted HER inhibitors have demonstrated limited activity in GAC. Hence, there is a pressing need to devise more efficacious anti-HER therapeutic strategies. Here, we examined the anti-tumor activity of neratinb, a pan-HER inhibitor, on GAC cells. Anti-proliferative effects of neratinib were determined using a cell proliferation assay and crystal violet staining. Annexin V/PI staining, radiation therapy and anoikis resistance and wound healing assays were carried out to examine the effects of neratinib on apoptosis, radio-sensitivity and cell motility, respectively. Quantitative reverse transcription-PCR (qRT-PCR) analyses were applied to further investigate the anti-tumor activity of neratinib. We found that neratinib sensitized GAC cells to 5FU, carboplatin and oxaliplatin. Moreover, we found that neratinib was synergistic with trametinib (an approved MEK inhibitor) and foretinib (a c-MET inhibitor) and potentiated radio-sensitivity of GAC cells. Furthermore, we found that neratinib diminished GAC cell proliferation along with downregulation of FOXM1 and its targets. Additionally, neratinib induced apoptosis along with upregulation of pro-apoptotic and downregulation of anti-apoptotic genes. Treatment with neratinib attenuated invasive ability of GAC cells as shown by reduced anoikis resistance, downregulation of EMT markers, and reduced width in scratch assay. Our findings indicate that neratinib provides the therapeutic potential in the treatment of GAC.
Keywords: Chemo-sensitivity; Gastric adenocarcinoma; HER family; Neratinib; Pan-HER; Radio-sensitivity.
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