miR-887-3p Inhibits the Progression of Colorectal Cancer via Downregulating DNMT1 Expression and Regulating P53 Expression.

Colorectal cancer (CRC) is the third most diagnosed cancer worldwide and the second leading cause of cancer-related deaths. Many researchers have reported that abnormal microRNAs (miRs) were expressed in CRC and participated in the occurrence and progression of CRC. However, there are few reports of miR-887-3p regulating CRC development. In the current study, we investigated the abnormal expression of miR-887-3p and also demonstrated its regulatory role and detailed molecular mechanism in CRC. Initially, miRNA expression data were obtained from TCGA-COAD that consisted of 453 CRC samples and 8 normal tissue samples. These were downloaded and analyzed to compare the expression level of miR-887-3p in CRC tissues to that in normal tissues. Moreover, 32 pairs of surgically resected CRC tumors and para-cancer tissues from our hospital were collected. Quantitative real-time PCR (qRT-PCR) was performed to detect miR-887-3p expression levels in CRC tissues, para-cancer tissues, several CRC cell lines, and an intestinal epithelial cell line. Following miR-887-3p mimic transfection in colon cancer SW480 cell line, the regulatory roles of miR-887-3p on cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT) were detected through CCK-8, flow cytometry, transwell assay, and Western blot. After potential targeting protein was predicted by bioinformatic websites, the luciferase reporter assay and Western blot were used to confirm the target of miR-887-3p. The targeting protein expressions were detected by Western blot and qRT-PCR. The relationship between miR-887-3p level and the effect of miR-887-3p on P53 expression was evaluated by Western blot and qRT-PCR. The effects of miR-887-3p on CRC cell growth in vivo by xenograft tumor experiments were investigated, and Ki-67 in tumor tissue was determined by immunohistochemistry. Results. The COAD data demonstrated that the expression levels of miR-887-3p in CRC clinical sample tissues and cell line cultures were remarkably lower than para-cancer normal tissues and NCM460 cells (normal colonic epithelial cell line). Functional experiments demonstrated that overexpression of miR-887-3p in SW480 cells significantly reduced proliferation, migration, invasion, and EMT, and promoted cancer cell apoptosis. Additionally, Western blot, qRT-PCR, and luciferase reporter assays confirmed that DNMT1 was a downstream target of miR-887-3p. Moreover, the blocking of DNMT1 by miR-887-3p mimics also promoted P53 expression. Finally, overexpression of DNMT1 in SW480 cells could partially reverse the regulatory effect of miR-887-3p mimics on CRC cell development. From in vivo experiments, overexpression of miR-887-3p could inhibit tumor growth in CRC xenograft mice and reduce the Ki-67 level. Conclusion. The microRNA miR-887-3p is a potential biomarker of CRC. It inhibited CRC cell proliferation, invasion, and EMT, and promoted cell apoptosis through targeting and downregulating DNMT1 and promoting P53 expression. Therefore, miR-887-3p may be a good biomarker and therapeutic target for CRC treatment.

Teng D ，Xia S ，Hu S ，Yan Y ，Liu B ，Yang Y ，Du X ... -  《-》

Transcription factor SP1-induced microRNA-146b-3p facilitates the progression and metastasis of colorectal cancer via regulating FAM107A.

Recent studies have provided compelling evidence regarding the association of microRNAs (miRNAs) with the progression and development of tumors. Among the miRNAs, the dysregulation of miR-146b-3p expression has been reported in several cancers, however, its effect on colorectal cancer (CRC) remains unexplored. Many studies have suggested a close correlation between the transcription factor (TF)-miRNA signal and cancer. The present study explored the effects of TF-miR-146b-3p axis on CRC and elucidated its downstream regulatory molecule. The expression levels of miR-146b-3p in CRC tissues and cell lines were assessed via quantitative real-time polymerase chain reaction (qRT-PCR). The impact of miR-146b-3p on CRC cell proliferation, migration, and invasion were analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) cell proliferation assay and transwell migration and invasion assay. Additionally, the impact of miR-146b-3p on CRC cell cycle and apoptosis was investigated using flow cytometry. The targets of miR-146b-3p, predicted by miRWalk database, were verified using a dual-luciferase reporter system. The expression levels of TFs were detected using qRT-PCR. The effects of miR-146b-3p and SP1 on FAM107A expression were assessed by performing qRT-PCR and western blotting. Chromatin Immunoprecipitation (ChIP) Assay was performed and JASPAR database was utilized to explore the regulatory relationship between the SP1 and miR-146b-3p. Increased expression of miR-146b-3p in CRC tissues and cell lines correlated with poor overall survival (OS). Upregulation of miR-146b-3p expression remarkably promoted the proliferation, migration, and invasion of CRC cells and suppressed their apoptosis. Furthermore, SP1 overexpression significantly elevated the miR-146b-3p expression, decreased the FAM107A expression, and promoted the G1/S transition. The miR-146b-3p overexpression also enhanced the effects of SP1 overexpression on CRC cell proliferation, migration, and invasion, whereas miR-146b-3p knockdown led to the opposite results. Mechanistically, miR-146b-3p functions as an oncogene by directly targeting FAM107A. Our results highlight the critical regulatory role played by SP1-induced miR-146b-3p expression in CRC development. Our results suggest that SP1/miR-146b-3p/FAM107A axis may be a potential therapeutic target for CRC.

Wang D ，Feng M ，Ma X ，Tao K ，Wang G ... -  《-》

The MiR-495/Annexin A3/P53 Axis Inhibits the Invasion and EMT of Colorectal Cancer Cells.

More and more reports have shown that the dysregulation of miRNAs can contribute to the progression and metastasis of human cancers. Many studies have shown that the down-regulation of the miR-495 level occurs in a variety of cancers, including colorectal cancer (CRC). However, the precise molecular mechanisms of miR-495 in CRC have not been well clarified. In the current study, we investigated the biological functions and molecular mechanisms of miR-495 in CRC cell lines. qRT-PCR was used to determine the level of miR-495 in CRC cell lines and tissues. A miR-495 mimic and inhibitor were transfected into CRC cells, and the effects of miR-495 on the invasion and EMT were explored by qRT-PCR as well as transwell and Western blot assays. Meanwhile, luciferase assays were performed to validate Annexin A3 as a miR-495 target in CRC cells. In our study, we found that miR-495 is down-regulated in CRC tissues and cell lines. Moreover, the low level of miR-495 was associated with increased expression of Annexin A3 in CRC tissues and cell lines. The invasion and EMT of CRC cells were suppressed by the overexpression of miR-495. However, the down-regulation of miR-495 promoted the invasion and EMT of CRC cells. Bioinformatics analysis predicted that Annexin A3 was a potential target gene of miR-495. Next, the luciferase reporter assay confirmed that miR-495 could directly target Annexin A3. Consistent with the effect of miR-495, the down-regulation of Annexin A3 by siRNA inhibited the invasion and EMT of CRC cells through the up-regulation of p53. The introduction of Annexin A3 in CRC cells partially blocked the effects of the miR-495 mimic. The introduction of miR-495 directly targeted Annexin A3 to inhibit the invasion and EMT of CRC cells by up-regulating p53, and the down-regulation of Annexin A3 was essential for inhibiting the invasion and EMT of CRC cells by overexpressing miR-495. Overall, the re-activation of the miR-495/Annexin A3/ p53 axis may represent a new strategy for overcoming metastasis of CRC.

Bai Z ，Wang J ，Wang T ，Li Y ，Zhao X ，Wu G ，Yang Y ，Deng W ，Zhang Z ... -  《-》

MiR-3622a-3p acts as a tumor suppressor in colorectal cancer by reducing stemness features and EMT through targeting spalt-like transcription factor 4.

Chang S ，Sun G ，Zhang D ，Li Q ，Qian H ... -  《Cell Death & Disease》

MiR-410-3p activates the NF-κB pathway by targeting ZCCHC10 to promote migration, invasion and EMT of colorectal cancer.

Colorectal cancer (CRC) is a prevalent malignancy of the digestive tract. miR-410-3p is involved in oncogenesis and development of CRC, but the specific regulation mechanism is still not known clearly. The expression of miR-410-3p and zinc finger CCHC-type containing 10 (ZCCHC10) in CRC cells was detected by qRT-PCR and western blot method, respectively. The dual-luciferase reporter gene detection was applied for determination of interaction between miR-410-3p and ZCCHC10. The wound healing assay and transwell assay were carried out to measure cell migration and invasive ability, respectively. The miR-410-3p expression levels were markedly increased, but ZCCHC10 levels were reduced in CRC cells and tissues. Dual-luciferase reporter gene detection indicated that miR-410-3p targeted ZCCHC10 directly. Functionally knockdown of ZCCHC10 or overexpression of miR-410-3p activated nuclear factor-κB (NF-κB) signaling pathway, promoted epithelial-mesenchymal transition (EMT) process, as well as cell migration and invasion of CRC cells. After adding NF-κB inhibitor BAY 11-708 to inhibit NF-κB pathway, the promoting effects of si-ZCCHC10 on cell migration, invasion and EMT of HT29 and SW480 cells were suppressed. Meanwhile, overexpression of ZCCHC10 inhibited the effects of miR-410-3p on cell migration, invasion and EMT of HT29 and SW480. miR-410-3p-mediated ZCCHC10 suppression regulates NF-κB activation, thereby promoting EMT process, cell migration and invasion of CRC cells. This study provides a new insight into the specific mechanism by which miR-410-3p mediates CRC progression.

Ma ZH ，Shi PD ，Wan BS 《-》