Cancer-associated fibroblast-derived exosomal microRNA-24-3p enhances colon cancer cell resistance to MTX by down-regulating CDX2/HEPH axis.

MicroRNA-24-3p (miR-24-3p) has been implicated as a key promoter of chemotherapy resistance in numerous cancers. Meanwhile, cancer-associated fibroblasts (CAFs) can secret exosomes to transfer miRNAs, which mediate tumour development. However, little is known regarding the molecular mechanism of CAF-derived exosomal miR-24-3p in colon cancer (CC). Hence, this study intended to characterize the functional relevance of CAF-derived exosomal miR-24-3p in CC cell resistance to methotrexate (MTX). We identified differentially expressed HEPH, CDX2 and miR-24-3p in CC through bioinformatics analyses, and validated their expression in CC tissues and cells. The relationship among HEPH, CDX2 and miR-24-3p was verified using ChIP and dual-luciferase reporter gene assays. Exosomes were isolated from miR-24-3p inhibitor-treated CAFs (CAFs-exo/miR-24-3p inhibitor), which were used in combination with gain-of-function and loss-of-function experiments and MTX treatment. CCK-8, flow cytometry and colony formation assays were conducted to determine cell viability, apoptosis and colony formation, respectively. Based on the findings, CC tissues and cells presented with high expression of miR-24-3p and low expression of HEPH and CDX2. CDX2 was a target gene of miR-24-3p and could up-regulate HEPH. Under MTX treatment, overexpressed CDX2 or HEPH and down-regulated miR-24-3p reduced cell viability and colony formation and elevated cell apoptosis. Furthermore, miR-24-3p was transferred into CC cells via CAF-derived exosomes. CAF-derived exosomal miR-24-3p inhibitor diminished cell viability and colony formation and increased cell apoptosis in vitro and inhibited tumour growth in vivo under MTX treatment. Altogether, CAF-derived exosomal miR-24-3p accelerated resistance of CC cells to MTX by down-regulating CDX2/HEPH axis.

Zhang HW ，Shi Y ，Liu JB ，Wang HM ，Wang PY ，Wu ZJ ，Li L ，Gu LP ，Cao PS ，Wang GR ，Ma YS ，Fu D ... -  《-》

Downregulated exosomal microRNA-148b-3p in cancer associated fibroblasts enhance chemosensitivity of bladder cancer cells by downregulating the Wnt/β-catenin pathway and upregulating PTEN.

Shan G ，Zhou X ，Gu J ，Zhou D ，Cheng W ，Wu H ，Wang Y ，Tang T ，Wang X ... -  《-》

Cancer-associated fibroblasts secreted miR-103a-3p suppresses apoptosis and promotes cisplatin resistance in non-small cell lung cancer.

Wang H ，Huang H ，Wang L ，Liu Y ，Wang M ，Zhao S ，Lu G ，Kang X ... -  《Aging-US》

CAFs secreted exosomes promote metastasis and chemotherapy resistance by enhancing cell stemness and epithelial-mesenchymal transition in colorectal cancer.

Hu JL ，Wang W ，Lan XL ，Zeng ZC ，Liang YS ，Yan YR ，Song FY ，Wang FF ，Zhu XH ，Liao WJ ，Liao WT ，Ding YQ ，Liang L ... -  《Molecular Cancer》

Effect of rs67085638 in long non-coding RNA (CCAT1) on colon cancer chemoresistance to paclitaxel through modulating the microRNA-24-3p and FSCN1.

It has been reported that rs67085638 in long non-coding RNAs (lncRNA)-CCAT1 was associated with the risk of tumorigenesis. Also, CCAT1 could affect chemoresistance of cancer cells to paclitaxel (PTX) via regulating miR-24-3p and FSCN1 expression. In this study, we aimed to investigate the effect of rs67085638 on the expression of CCAT1/miR-24-3p/FSCN1 and the response of colon cancer to the treatment of PTX. 48 colon cancer patients were recruited and grouped by their genotypes of rs67085638 polymorphism as a CC group (N = 28) and a CT group (N = 20). PCR analysis, IHC assay and Western blot, TUNEL assay and flow cytometry were conducted. LncRNA-CCAT1 and FSCN1 mRNA/protein were overexpressed, whereas miR-24-3p was down-regulated in the CT-genotyped patients and cells compared with those in the CC-genotyped patients and cells. The survival of colon cancer cells was decreased, whereas the apoptosis of colon cancer cells was increased by PTX treatment in a dose-dependent manner. MiR-24-3p was validated to target lncRNA-CCAT1 and FSCN1 mRNA, and the overexpression of CCAT1 could reduce the expression of miR-24-3p although elevating the expression of FSCN1. Knockdown of lncRNA-CCAT1 partly reversed the suppressed growth of CT-genotyped tumours. And the knockdown of lncRNA-CCAT1 partly reversed the dysregulation of lncRNA-CCAT1 and FSCN1 mRNA/protein in rs67085638-CT + NC shRNA mice. The findings of this study demonstrated that the presence of the minor allele of rs67085638 increased the expression of CCAT1 and accordingly enhanced the resistance to PTX. Down-regulation of CCAT1 significantly re-stored the sensitivity to PTX of colon cancer cells.

Xiao ZS ，Zhao L ，Zhang XN ，Li HX ，Yin ZH ... -  《-》