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Background: Colorectal cancer (CRC) is a prevalent malignancy with diverse molecular characteristics. The NGS-based approach enhances our comprehension of genomic landscape of CRC and may guide future advancements in precision oncology for CRC patients. Method: In this research, we conducted an analysis using Next-Generation Sequencing (NGS) on samples collected from 111 individuals who had been diagnosed with CRC. We identified somatic and germline mutations and structural variants across the tumor genomes through comprehensive genomic profiling. Furthermore, we investigated the landscape of driver mutations and their potential clinical implications. Results: Our findings underscore the intricate heterogeneity of genetic alterations within CRC. Notably, BRAF, ARID2, KMT2C, and GNAQ were associated with CRC prognosis. Patients harboring BRAF, ARID2, or KMT2C mutations exhibited shorter progression-free survival (PFS), whereas those with BRAF, ARID2, or GNAQ mutations experienced worse overall survival (OS). We unveiled 80 co-occurring and three mutually exclusive significant gene pairs, enriched primarily in pathways such as TP53, HIPPO, RTK/RAS, NOTCH, WNT, TGF-Beta, MYC, and PI3K. Notably, co-mutations of BRAF/ALK, BRAF/NOTCH2, BRAF/CREBBP, and BRAF/FAT1 correlated with worse PFS. Furthermore, germline AR mutations were identified in 37 (33.33%) CRC patients, and carriers of these variants displayed diminished PFS and OS. Decreased AR protein expression was observed in cases with AR germline mutations. A four-gene mutation signature was established, incorporating the aforementioned prognostic genes, which emerged as an independent prognostic determinant in CRC via univariate and multivariate Cox regression analyses. Noteworthy BRAF and ARID2 protein expression decreases detected in patients with their respective mutations. Conclusion: The integration of our analyses furnishes crucial insights into CRC's molecular characteristics, drug responsiveness, and the construction of a four-gene mutation signature for predicting CRC prognosis.
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PURPOSE: Chemotherapy remains the primary treatment used to improve overall survival and quality of life for patients with gastric cancer (GC); however, multidrug resistance is a major reason underlying failure of chemotherapy. Drug resistance (DR) can arise because of molecular changes inhibiting drug-target interactions; for example, overexpression of drug efflux pumps, such as P-gp, mediated by the activation of AP-1. BATF2 is a suppressor of AP-1; therefore, this study aimed to determine how BATF2 interacts with AP-1to inhibit DR in GC cells. METHODS: Expression of BATF2 in drug-responsive and non-responsive GC tumor tissues was evaluated by quantitative PCR and western blotting. Further, expression levels of BATF2- and AP-1-related genes were confirmed in vincristine-resistant SGC7901/VCR cells treated with cisplatin or 5-fluorouracil. A BATF2 overexpression system was established in SGC7901/VCR cells, and then AP-1 also overexpressed in the cells with upregulated BATF2 levels. Further, an AP-1 knockdown system was generated in SGC7901/VCR cells. MTT and flow cytometry assays were performed in the BATF2/AP-1 overexpression system, to evaluate cell proliferation, cell cycle effects, and apoptosis, and the expression of various proteins was detected by western blotting in AP-1/BATF2 overexpression cells. Finally, the effects of BATF2 overexpression in an in vivo nude mouse GC model were evaluated. RESULTS: We found that BATF2 was overexpressed in tissues from patients with non-responsive GC and the VCR resistance cell line, SGC7901/VCR, while levels of c-Fos and c-Jun were reduced in the SGC7901/VCR cell line. BATF2 overexpression suppressed levels of AP-1 and P-gp. Further, our data demonstrate that cell proliferation is suppressed, and the cell cycle and apoptosis are induced in SGC7901/VCR cells overexpressing both AP-1 and BATF2. Overexpression of AP-1 restored levels of genes downstream of AP-1 in BATF2 overexpressing cells. Compared with controls, tumor growth of SGC7901/VCR cells in nude mice was suppressed in the BATF2 overexpression group. CONCLUSION: AP-1 down-regulation by BATF2 overexpression or AP-1 knockdown can inhibit DR in GC cells. These findings suggest that BATF2 inhibits DR in SGC7901/VCR GC cells by down-regulating AP-1 expression.
