Colorectal cancer (CRC) is the second leading cause of cancer‐related deaths worldwide. However, a biomarker for a sensitive and simple diagnostic test and highly effective target therapy of CRC is still clinically unavailable. This study is to investigate the evidence and significance of plasma GPC1 positive exosomes as a biomarker of CRC. Results showed that GPC1+ exosomes were successfully isolated from tissues and plasma. The percentage of GPC1+ exosomes and the GPC1 protein expression in exosomes from tumour tissues and plasma of CRC patients before surgical treatment was significantly elevated compared to that in the peritumoural tissues and the plasma of healthy controls. miR‐96‐5p and miR‐149 expression in tumour tissues and plasma of CRC patients as well as in the GPC1+ exosomes from CRC patients were significantly decreased compared to that in the peritumoural tissues and the plasma of healthy controls. Two months after surgical treatment, levels of all tested markers significantly normalized. Overexpression of miR‐96‐5p and miR‐149 significantly decreased GPC1 expression in HT‐29 and HCT‐116 cells, xenograft tumours, plasma in mice bearing HT‐29 and HCT‐116 tumours, and the secretion of GPC1+ exosomes from the HT‐29 and HCT‐116 cells and xenograft tumours. Overexpression of miR‐96‐5p and miR‐149 significantly decreased cell viability and increased cell apoptosis in HT‐29 and HCT‐116 cells, and inhibited the growth of xenograft HT‐29 and HCT‐116 tumours. In conclusion, the increased plasma GPC1+ exosomes and reduced plasma miR‐96‐5p and miR‐149 expression are specific markers for the diagnosis of CRC and targets for the therapy of CRC.

Emerging evidence has validated the vital role of long non‐coding RNA (lncRNA) in the chemoresistance of cancer treatment. In the present study, we investigate the function of lncRNA NR2F1‐AS1 on oxaliplatin (OXA) resistance of hepatocellular carcinoma (HCC) and discover the underlying molecular mechanism. Results revealed that lncRNA NR2F1‐AS1 was up‐regulated in oxaliplatin‐resistant HCC tissue and cells using microarray analysis and RT‐PCR. Meanwhile, ABCC1 protein was overexpressed in OXA‐resistant HCC cells (Huh7/OXA and HepG2/OXA). In vitro, NR2F1‐AS1 knockdown reduced the invasion, migration, drug‐resistant gene (MDR1, MRP5, LRP1) and IC50 value in Huh7/OXA and HepG2/OXA cells. In vivo, NR2F1‐AS1 knockdown decreased the tumour weight of HCC cells. Bioinformatics tools and luciferase reporter assay confirmed miR‐363 targeted the 3′‐UTR of NR2F1‐AS1 and ABCC1 mRNA, presenting that NR2F1‐AS1 promoted ABCC1 expression through endogenous sponging miR‐363. In summary, results conclude that NR2F1‐AS1 regulates HCC OXA resistance through targeting miR‐363‐ABCC1 pathway, providing a vital theoretic mechanism and therapeutic target for HCC chemoresistance.

Colorectal cancer (CRC) has a high prevalence and mortality rate. Biomarkers for predicting the recurrence of CRC are not clinically available. This study investigated the role of circulating miR-15b in the prediction of CRC recurrence and the associated mechanism. miR-15b levels in plasma and tissues were measured by real-time PCR. Metastasis suppressor-1 (MTSS1) and Klotho protein expression were detected by Western blot and immunohistochemistry. Invasion and migration of CRC tumor cells were measured by transwell plates. Liver metastasis was established by intraspleen injection of HCT116 cells. Plasma miR-15b levels were significantly higher in CRC patients than in healthy controls, in CRC patients with metastasis than in CRC patients without metastasis, and in CRC patients with recurrence than in CRC patients without recurrence in the 5-year follow-up. miR-15b level in CRC tumors was significantly higher than that in peritumoral tissues. High plasma miR-15b level and negative MTSS1 and Klotho expression in tumor tissues significantly correlated with poor survival. Inhibition of miR-15b activity by adenovirus carrying antimiR-15b sequence significantly increased MTSS1 and Klotho protein expression and subsequently decreased colony formation ability, invasion, and migration of HCT116 cells in vitro and liver metastasis of HCT116 tumors in vivo. In conclusion, high abundance of circulating miR-15b correlated with tumor metastasis, recurrence, and poor patient prognosis through downregulation of MTSS1 and Klotho protein expression.

Abstract. RAS protein activator like 2 (RASAL2) is a RAS-GTPase-activating protein and has recently been identified to be a tumor suppressor in various types of human cancer; however, the function of RASAL2 in colorectal carcinoma (CRC) remains unclear. In the present study, the function of RASAL2 in CRC cells was investigated using a RASAL2 loss-of-function cell model. RASAL2 short hairpin RNA was transfected into the human CRC cell lines LoVo, SW620 and HCT116, and the wild-type colon cell line NCM460. The subsequent downregulation of RASAL2 was evaluated using western blot and reverse transcription-quantitative polymerase chain reaction analyses. It was observed that RASAL2 expression was significantly decreased in human CRC tissues and cell lines (P<0.01). In the loss-of-function cell models, RASAL2 expression was decreased significantly, while cell proliferation, colony formation, migration and invasion were increased (all P<0.01). These effects were associated with the induction of epithelial-mesenchymal transition and Raf/mitogen-activated protein kinase hyperactivation. The results of the present study indicate that RASAL2 is a potential therapeutic target to inhibit CRC progression and metastasis.

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