Involvement of microRNA-141-3p in 5-fluorouracil and oxaliplatin chemo-resistance in esophageal cancer cells via regulation of PTEN.

microRNAs (miRNAs) act as a major regulator of acquired chemo-resistance in various types of cancer therapeutics. This study investigated the contribution of miRNAs in influencing multiple drug resistance in esophageal squamous cell carcinoma (ESCC). The sensitivity of four ESCC cell lines (EC109, EC9706, TE-1 and KYSE-150) to 5-fluorouracil (5-FU) and oxaliplatin (OX) was determined by MTT assay. A 5-FU and OX-resistant subline, EC9706R, was established by continuous exposure to stepwise increasing concentration of 5-FU and OX. Microarray technology was used to compare the differential expression of miRNAs between resistant cells and parental cells. Chemo-sensitivity assay was performed to evaluate drug response in EC9706R cells transfected with miRNA mimic or inhibitor. The direct targets of miRNA were identified by employing pathway analysis and then confirmed with luciferase assay. Sixty ESCC tissue samples and their paired adjacent normal tissues were collected to validate the expression of identified miRNA. Mouse models were further utilized to investigate the function of miRNA on acquired chemo-resistance. MicroRNA panel results indicated that a total of 12 miRNAs were differentially expressed and miR-141-3p was highly over expressed in resistant cells. Inhibition of miR-141-3p reversed acquired chemo-resistance in EC9706R cells by stimulating apoptosis. The expression of miR-141-3p was significantly increased in ESCC tissue samples compared to their matched distant normal tissues. In addition, the elevated miR-141-3p expression was found to be associated with ESCC differentiation status and TNM stage. Moreover, Phosphatase and tensin homolog (PTEN) was identified as direct target of miR-141-3p. Western blot exhibited altered protein levels of PTEN, Akt, and PI3k with miR-141-3p inhibitor. An inverse correlation between PTEN expression and miR-141-3p expression was also observed in tissue samples. EC9706R xenograft mouse model became sensitized to 5-FU and OX treatment following miR-141-3p inhibitor transfection in vivo. Our study demonstrated that miR-141-3p contributed to an acquired chemo-resistance through PTEN modulation both in vitro and in vivo.

Differences in Genomic Alterations and Accumulations of Heavy Metals Between Advanced Non-small Cell Lung Cancer Patients with and without Bone Metastasis.

Purpose: Bone metastasis (BoM) has been closely associated with increased morbidity and poor survival outcomes in patients with non-small cell lung cancer (NSCLC). Given its significant implications, this study aimed to systematically compare the biological characteristics between advanced NSCLC patients with and without BoM. Methods: In this study, the genomic alterations from the tumor tissue DNA of 42 advanced NSCLC patients without BoM and 67 patients with BoM and were analyzed by a next-generation sequencing (NGS) panel. The serum concentrations of 18 heavy metals were detected by inductively coupled plasma emission spectrometry (ICP-MS). Results: A total of 157 somatic mutations across 18 mutated genes and 105 somatic mutations spanning 16 mutant genes were identified in 61 out of 67 (91.05%) patients with BoM and 37 of 42 (88.10%) patients without BoM, respectively. Among these mutated genes, NTRK1, FGFR1, ERBB4, NTRK3, and FGFR2 stood out exclusively in patients with BoM, whereas BRAF, GNAS, and AKT1 manifested solely in those without BoM. Moreover, both co-occurring sets of genes and mutually exclusive sets of genes in patients with BoM were different from those in patients without BoM. In addition, the serum concentrations of Cu and Sr in patients with BoM were significantly higher than in patients without BoM. One of our aims was to explore how these heavy metals associated with BoM interacted with other heavy metals, and significant positive correlations were observed between Cu and Co, between Cu and Cr, between Sr and Ba, and between Sr and Ni in patients with BoM. Given the significant impacts of molecular characteristics on patients' prognosis, we also observed a noteworthy negative correlation between EGFR mutations and Co, alongside a significant positive correlation between TP53 mutations and Cd. Conclusions: The genomic alterations, somatic interactions, key signaling pathways, functional biological information, and accumulations of serum heavy metals were markedly different between advanced NSCLC patients with and without BoM, and certain heavy metals (e.g., Cu, Sr) might have potentials to identify high-risk patients with BoM.

Upregulation of microRNA-98 increases radiosensitivity in esophageal squamous cell carcinoma.

Although radiation resistance is a common challenge in the clinical treatment of esophageal squamous cell carcinoma (ESCC), an effective treatment strategy has yet to be developed. Aberrant expression of microRNAs (miRNAs) is responsible for cancer sensitivity to radiation. In this study, we aimed to identify the miRNAs that are associated with radioresistance in ESCC. We used a miRNA microarray to perform a comparison of miRNA expression in both ESCC parental and acquired radioresistance cell lines. qRT-PCR was used to confirm the alterations. Cell radiosensitivity was determined with a survival fraction assay. Functional analyses of the identified miRNA in ESCC cells with regard to metastasis and apoptosis were performed by transwell assays and flow cytometry. The miRNA targets were identified with pathway analysis and confirmed with a luciferase assay. miR-98 was recognized as the most downregulated miRNA in established radioresistant cell line. AmiR-98 mimic enforced the expression of miRNA-98 and made ESCC cells sensitive to radiotherapy, while anti-miR-98 reversed this process. Optimal results were achieved by decreasing cellular proliferation, decreasing cell migration and inducing apoptosis. The luciferase target gene analysis results showed that the overexpression of miRNA-98 inhibited tumor growth and resistance tolerance by directly binding to the BCL-2 gene. Our study indicated that increasing miRNA-98 expression can be used as a potential radiosensitive therapeutic strategy for treating esophageal cancer cells.