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Background: Colon cancer (CC) is the second most common gastrointestinal malignancy. About one in five patients have already developed distant metastases at the time of initial diagnosis, and up to half of patients develop distant metastases from initial local disease, which leads to a poor prognosis for CC patients. Necroptosis plays a key role in promoting tumor growth in different tumors. The purpose of this study was to construct a prognostic model composed of necroptosis-related genes (NRGs) in CC., Methods: The Cancer Genome Atlas was used to obtain information on clinical features and gene expression. Gene expression differential analysis, weighted gene co-expression network analysis, univariate Cox regression analysis and the least absolute shrinkage and selection operator regression algorithm were utilized to identify prognostic NRGs. Thereafter, a risk scoring model was established based on the NRGs. Biological processes and pathways were identified by gene ontology and gene set enrichment analysis (GSEA). Further, protein-protein interaction and ceRNA networks were constructed based on mRNA-miRNA-lncRNA. Finally, the effect of necroptosis related risk score on different degrees of immune cell infiltration was evaluated., Results: CALB1, CHST13, and SLC4A4 were identified as NRGs of prognostic significance and were used to establish a risk scoring model. The time-dependent receiver operating characteristic curve analysis revealed that the model could well predict the 1-, 3-, and 5-year overall survival (OS). Further, GSEA suggested that the NRGs may participate in biological processes, such as the WNT pathway and JAK-Stat pathway. Eight key hub genes were identified, and a ceRNA regulatory network, which comprised 1 lncRNA, 5 miRNAs and 3 mRNAs, was constructed. Immune infiltration analysis revealed that the low-risk group had significantly higher immune-related scores than the high-risk group. A nomogram of the model was constructed based on the risk score, necroptosis, and the clinicopathological features (age and TNM stage). The calibration curves implied that the model was effective at predicting the 1-, 3-, and 5-year OS of CC., Conclusion: Our NRG-based prognostic model can assist in the evaluation of CC prognosis and the identification of therapeutic targets for CC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Yang, Lu, Peng, Zhang, Zhang, Guo, Ma, Hua and Chen.)

Long non-coding RNAs (lncRNAs) regulate a series of biological processes, and their anomalous expression exerts critical roles in progression of multiple malignancies, including colorectal cancer (CRC). The present study was designed to provide new ideas and perspectives for the role of lncRNA MCF2L-AS1 and disclose the underlying mechanism in CRC. Herein, we observed that MCF2L-AS1 expression was enriched in CRC tissues and cell lines. Additionally, silencing of MCF2L-AS1 dramatically impeded cell proliferation, invasion and migration capacities of CRC, and distinctly attenuated the expression of invasion associated targets MMP-2 and MMP-9. Moreover, depletion of MCF2L-AS1 apparently restricted the glucose consumption and lactate production, and downregulated GLUT1 and LDHA expression. More importantly, we predicted and verified that MCF2L-AS1 acted as a molecular sponge for miR-874-3p and inversely regulated miR-874-3p expression. Interesting, FOXM1 was identified as direct target of miR-874-3p, and positively modulated by MCF2L-AS1 through sponging miR-874-3p. Mechanistically, MCF2L-AS1 accelerated cell proliferation, invasion and glycolysis through competitively binding to miR-874-3p, leading to enhance FOXM1 expression. Collectively, these outcomes highlighted that MCF2L-AS1 acted as a motivator by modulating the miR-874-3p/FOXM1 axis, thereby aggravating tumorigenesis and glycolysis progress of CRC, disclosing that MCF2L-AS1 may serve as a valuable and promising therapeutic strategy for CRC., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.)

Background: Cancer-associated fibroblasts (CAFs) have been intensively studied in recent studies with aims of finding more concrete evidence on their mechanism of involvement in tumor progression, which is currently unknown. CAFs can secrete exosomes which are loaded with proteins, lipids and RNAs, all of which affect tumor microenvironment. The present study identified microRNA-93-5p (miR-93-5p) as a novel exosomal cargo responsible for the pro-tumorigenic effects of CAFs on colorectal cancer (CRC)., Methods: CAFs and normal fibroblasts (NFs) were isolated from cancerous tissues and matched with paracancerous tissues that had been surgically resected from CRC patients. The interaction among miR-93-5p, forkhead box A1 (FOXA1) and TGFB3 was identified through ChIP and dual luciferase reporter assays. The proliferation and apoptosis of SW480 cells co-cultured with CAFs-derived exosomes under irradiation were evaluated by CCK-8, colony formation, and flow cytometric assays. Tumorigenesis of SW480 cells in nude mice was assessed under the irradiation., Results: FOXA1 was found to be associated with reduced radioresistance in CRC cells and was verified as a target of miR-93-5p. CAFs-derived exosomes contained higher miR-93-5p than those from NFs, which augmented SW480 cell proliferation and rescued them from radiation-induced apoptosis. miR-93-5p was identified as a mediator of the exosomal effects of CAFs on SW480 cells, possibly through downregulating FOXA1 and upregulating TGFB3. FOXA1 could bind to the promoter of TGFB3, thereby inhibiting nuclear accumulation of TGFB3. Also, CAFs-derived exosomes containing miR-93-5p increased the tumor growth of SW480 cells in irradiated nude mice., Conclusion: The present study identifies miR-93-5p as a specific exosomal cargo that rescues CRC cells against radiation-induced apoptosis.

The present study was aimed to explore the functional role of microRNA (miR)-29b in colon cancer, as well as underlying mechanisms. Expressions of miR-29b and folate receptor 1 (FOLR1) were measured in both human colon tumor samples and cell lines. Colon cancer cell lines SW480 and SW620 were transfected with miR-29b mimic, antisense oligonucleotides (ASO)-miR-29b, small interfering (siRNA) against FOLR1 (si-FOLR1), or corresponding negative controls (NCs), and then were incubated with or without oxaliplatin (L-OHP). Thereafter, cell viability, cytotoxicity, cell apoptosis, and expression of FOLR1, ATP Binding Cassette Subfamily G Member 2 (ABCG2) and p-glycoprotein (p-gp) were analyzed. We found that miR-29b was significantly decreased, while FOLR1 was statistically elevated in colon cancer samples and cell lines compared to the nontumor samples and nontumourigenic immortalized human colon epithelial cell line FHC. Overexpression of miR-29b markedly inhibited cell viability, promoted sensitivity to L-OHP, stimulated cell apoptosis (all p < .05), and decreased the levels of ABCG2 and p-gp in cancer cells, whereas suppression of miR-29b showed contrary results. Moreover, we observed that FOLR1 was a direct target of miR-29b and was negatively regulated by miR-29b. In addition, the findings revealed that the effects of FOLR1 inhibition on cell viability, sensitivity to L-OHP, cell apoptosis, and the levels of ABCG2 and p-gp were similar to overexpression of miR-29b. Taken together, our study suggests that miR-29b inhibits cell growth and promotes sensitivity to L-OHP in colon cancer by targeting FOLR1., (© 2019 International Union of Biochemistry and Molecular Biology.)

Objective: To predict and identify the target gene of miR-145, and to explore the underlying mechanism of the inhibition of miR-145 on drug resistance to Oxaliplatin (L-OHP) in human colorectal cancer cells., Methods: L-OHP-resistant human colorectal cancer cell line (HCT116/L-OHP) was established in vitro by exposing to increased concentrations of L-OHP in cell culture medium. MiR-145-mimics and its negative control (NC-miRNA) were transfected into HCT116/L-OHP cells using liposome to establish HCT116/L-OHP mimics over-expressing miR-145 and HCT116/L-OHP NC . The target genes of miR-145 were predicted by bioinformatic analysis, and validated by dual luciferase activity assay. After determination of G protein coupled receptor 98(GPR98) as target gene, corresponding plasmids were constructed and transfected to establish HCT116/L-OHP GPR98 over-expressing GPR98 and HCT116/L-OHP control . HCT116/L-OHP cells over-expressing both GPR98 and miR-145 (HCT116/L-OHP mimics+GPR98 ) were acquired through modification of the binding sites of GPR98 cDNA with miR-145. CCK-8 assay was used to assess the proliferation (A value) and sensitivity to L-OHP (the lower the IC50, the stronger the sensitivity) in HCT116/L-OHP cells. Real-time quantitative PCR was used to measure the mRNA expression of miR-145 and GPR98. Western blot was used to examine the protein expression of GPR98 and drug-resistant associated protein, such as P-glycoprotein (gp), multiple drug-resistance protein 1(MRP1), cancer-inhibition gene PTEN., Results: HCT116/L-OHP cell line was successfully established with IC 50 of (42.34±1.05) mg/L and miR-145 mRNA expression of 0.27±0.04, which was higher than (9.81±0.95) mg/L (t=39.784, P=0.000) and lower than 1.00±0.09 (t=13.021, P=0.000) in HCT116 cells. Based on HCT116/L-OHP cells, HCT116/L-OHP mimics cells were established successfully, with relative miR-145 expression of 10.01±1.05, which was higher than 1.06±0.14 in HCT116/L-OHP NC and 1.00±0.16 in HCT116/L-OHP (F=161.797, P=0.000). GPR98 was identified to be the target gene of miR-145. The relative mRNA and protein expressions of GPR98 in HCT116/L-OHP GPR98 cells were 8.48±0.46 and 1.71±0.09, respectively, which were higher than those in HCT116/L-OHP control (mRNA: 3.65±0.40, protein: 1.21±0.10) and HCT116/L-OHP (mRNA: 3.49±0.35, protein: 1.22±0.08; all P<0.05). The A value was 1.31±0.10, and the relative protein expressions of P-gp and MRP1 were 1.53±0.18 and 1.49±0.20 in HCT116/L-OHP GPR98 cells, which were higher than those in HCT116/L-OHP (A value: 0.82±0.08, relative protein expression: 1.00±0.06 and 1.21±0.13, all P<0.05). The A value was 0.89±0.08, and the relative protein expressions of P-gp and MRP were 1.02±0.24 and 1.38±0.25 in HCT116/L-OHP mimics+GPR98 cells, which were higher than those in HCT116/L-OHP mimics (A value: 0.20±0.05, relative protein expression: 0.20±0.07, 0.55±0.10, all P<0.05). The relative protein expression of PTEN in HCT116/L-OHP GPR98 cells was 0.12±0.03, which was lower than 1.25±0.14 in HCT116/L-OHP cells(P<0.05). In addition, relative protein expressions of P-gp and MRP1 were 1.02±0.24 and 1.38±0.25 in HCT116/L-OHP mimics+GPR98 cells, which were higher than those in HCT116/L-OHP mimics cells (0.20±0.07 and 0.55±0.10), while PTEN expression in HCT116/L-OHP mimics+GPR98 cells was lower as compared to HCT116/L-OHP mimics cells (1.41±0.16 vs. 1.98±0.13, P<0.05)., Conclusion: MiR-145 inhibits drug resistance to L-OHP of HCT116 cells through suppressing the expression of target gene GPR98.

Chemoresistance is a major obstacle to cancer therapy including that of colon cancer (CC). Although the dysregulation of many miRNAs has been implicated in 5-fluorouracil (5-FU) resistance in CC cells, the specific role of miR-20b in chemoresistance has not been documented. In the present study, we first determined the expression of miR-20b by RT-PCR and the levels of a disintegrin and metalloprotease 9 (ADAM9) and epidermal growth factor receptor (EGFR) by western blotting in CC and adjacent non-cancerous tissues from 5-FU-sensitive or -resistant CC patients. Subsequently, 5-FU-sensitive (HCT116) and -resistant (HCT116-R) cells were obtained, and the levels of miR-20b, ADAM9 and EGFR were detected. Meanwhile, the 5-FU resistance of the cells was examined by assessing cell viability (by MTT assay) and apoptosis (by flow cytometry). After transfection of miR-20b into HCT116-R cells, drug resistance was reexamined. We then confirmed the relationship between miR-20b and ADAM9 by luciferase reporter assay. Finally, 5-FU resistance in HCT116 and HCT116-R cells was compared after transfection with miR-20b. Our results showed that miR-20b was expressed at lower levels in the 5-FU-resistant tissues and cells than in the 5-FU-sensitive tissues and cells. The opposite was the case for expression of ADAM9 and EGFR. In addition, we demonstrated that ADAM9 is a direct target of miR-20b and that miR-20b decreased the 5-FU resistance of HCT116-R cells. Our findings suggest that miR-20b reduces 5-FU resistance to induce apoptosis in vitro by suppressing ADAM9/EGFR in CC cells.

Colorectal cancer (CRC) is a leading cause of cancer-related death worldwide. Deregulation of microRNAs (miRNAs) has been reported to participate in CRC progression. In the present study, we observed downregulation of miR-218 and upregulation of YEATS domain containing 4 (YEATS4) in CRC tissues and in multidrug-resistant HCT-116/L-OHP cells compared with these levels in normal tissues and parental HCT-116 cells, respectively. The results indicated that miR-218 overexpression significantly decreased the IC50 value of oxaliplatin (L-OHP) in the HCT-116/L-OHP cells, and suppression of miR-218 significantly enhanced the IC50 of L-OHP in the HCT-116 cells. Flow cytometric analysis showed that miR-218 overexpression alone promoted cell apoptosis in the HCT-116/L-OHP cells, which was further enhanced in response to L-OHP, and miR-218 inhibition decreased cell apoptosis in the HCT-116 cells following treatment with L-OHP. Western blot analysis indicated that, compared with the small increase observed in HCT-116 cells, the relative LC3 II level in HCT-116/L-OHP cells after lysosome inhibition via chloroquine (CQ) was markedly upregulated following L-OHP treatment, suggesting induction of autophagy. Exposure of HCT-116/L-OHP cells to L-OHP after control mimic transfection increased autophagic flux, as reflected by increased LC3 II levels, while miR-218 overexpression partly reversed L-OHP-mediated LC3 II accumulation. Additionally, both miR-218 overexpression and CQ treatment promoted L-OHP-induced HCT-116/L-OHP cell apoptosis. Molecularly, our results confirmed that miR-218 directly targets the YEATS4 gene and inhibits YEATS4 expression. Furthermore, YEATS4 overexpression without the 3'-untranslated region (3'-UTR) restored miR-218-inhibited YEATS4 and LC3 II expression, and abolished miR-218-stimulated cell viability loss and cell apoptosis increase in response to L-OHP. In conclusion, miR-218 sensitized HCT-116/L-OHP cells to L-OHP-induced cell apoptosis via inhibition of cytoprotective autophagy by targeting YEATS4 expression.

Cisplatin (DDP) based chemotherapy is still the main strategy of human gastric cancer (GC) treatment. However, drug resistance is a major obstacle for DDP chemotherapy. Recent studies indicated that the resistance could be modulated by the regulation of dysregulated microRNAs (miRs). Previous study also found miR-34a was associated with cell proliferation and apoptosis in human GC; however, the relationship between miR-34a and DDP resistance still remains unexplored. The purpose of this study was to investigate whether miR-34a is associated with DDP resistance in human GC cells. Our study found that the expression of miR-34a was significantly decreased in DDP resistance human GC tissues and DDP resistance human GC SGC7901/DDP cells compared with normal GC tissues and cells. Upregulation of miR-34a enhanced the DDP sensitivity of SGC7901/DDP cells to DDP through the inhibition of cell proliferation and induction of cell apoptosis; on the other hand downregulation of miR-34a could weaken the DDP sensitivity of SGC7901 cells to DDP. Further study found that MET was a direct target of miR-34a and the regulation of MET could affect the DDP sensitivity of SGC7901/DDP cells. Moreover, our study also indicated that up-regulation of miR-34a could decrease the expression of MET in SGC7901/DDP cells. Therefore, our findings suggested miR-34a could modulate human gastric cancer cell DDP sensitivity by regulation of cell proliferation and apoptosis via targeting MET, potentially benefiting human GC treatment in the future.