MicroRNA 32 promotes cell proliferation,migration, and suppresses apoptosis in colon cancer cells by targeting OTU domain containing 3

Colorectal cancer is considered as the fourth leading reason of cancer-linked deaths worldwide. However, our knowledge about its pathogenic mechanism remains inadequate. MicroRNA 32 (miR-32), a member of small noncoding RNAs, has been found vital roles in tumorigenesis. This study studied its functions and underlying mechanism in colorectal cancer. The experiment revealed the obvious upregulation of miR-32 in colorectal cancer tissues and six cancer cell lines, compared with normal tissues and cells. Moreover, miR-32 upregulation reduced cell apoptosis and promoted cell proliferation and migration, while its downregulation displayed opposite effects. Dual luciferase reporter assays proved that miR-32 bound to the 3′-untranslated region (3′-UTR) of OTU domain containing 3 (OTUD3), suggesting that miR-32 directly targeted OTUD3. Further experiments demonstrated that overexpression of miR-32 could reduce the expression level of OTUD3. Furthermore, OTUD3 silence promoted proliferation and motility and decreased apoptosis for HCT116 cells and restored partly miR-32-mediated cell proliferation, migration, and antiapoptosis for colon cancer. Therefore, our study indicated that miR-32 enhanced cell proliferation and motility abilities, and inhibited apoptosis by directly targeting OTUD3 in colon cancer cells, which implied that miR-32 was hopeful to be a biomarker or target used for diagnosis and therapy of colon cancer.     

MicroRNA-218 Inhibits Cell Cycle Progression and Promotes Apoptosis in Colon Cancer by Downregulating BMI1 Polycomb Ring Finger Oncogene

Deregulated miRNAs participate in colorectal carcinogenesis. In this study, miR-218 was found to be downregulated in human colorectal cancer (CRC) by miRNA profile assay. miR-218 was silenced or downregulated in all five colon cancer cells (Caco2, HT29, SW620, HCT116 and LoVo) relative to normal colon tissues. miR-218 expression was significantly lower in 46 CRC tumor tissues compared with their adjacent normal tissues (P < 0.001). Potential target genes of miR-218 were predicted and BMI1 polycomb ring finger oncogene (BMI-1), a polycomb ring finger oncogene, was identified as one of the potential targets. Upregulation of BMI-1 was detected in CRC tumors compared with adjacent normal tissues (P < 0.001) and in all five colon cancer cell lines. Transfection of miR-218 in colon cancer cell lines (HCT116, HT29) significantly reduced luciferase activity of the wild-type construct of BMI-1 3′ untranslated region (3′UTR) (P < 0.001), whereas this effect was not seen in the construct with mutant BMI-1 3′UTR, indicating a direct and specific interaction of miR-218 with BMI-1. Ectopic expression of miR-218 in HCT116 and HT29 cells suppressed BMI-1 mRNA and protein expression. In addition, miR-218 suppressed protein expression of BMI-1 downstream targets of cyclin-dependent kinase 4, a cell cycle regulator, while upregulating protein expression of p53. We further revealed that miR-218 induced apoptosis (P < 0.01), inhibited cell proliferation (P < 0.05) and promoted cell cycle arrest in the G2 phase (P < 0.01). In conclusion, miR-218 plays a pivotal role in CRC development through inhibiting cell proliferation and cycle progression and promoting apoptosis by downregulating BMI-1.     

LncRNA-UCA1 modulates progression of colon cancer through regulating the miR-28-5p/HOXB3 axis

Emerging evidence has shown that the long noncoding RNA urothelial carcinoma–associated 1 (UCA1) plays a tumor-promoting role in colorectal cancer, while miR-28-5p shows tumor-inhibitory activity in several tumor types. However, the mechanisms both of these in colon cancer progression are still unknown. In this work, the detailed roles and mechanisms of UCA1 and its target genes in colon cancer were studied. The results showed that UCA1 was upregulated in colon cancer tissues when compared with the adjacent nonhumorous tissues, as well as in the various colon cancer cell lines, but the expression of miR-28-5p showed an opposite trend. Furthermore, a high UCA1 level in colon cancer tissues is positively associated with the tumor size and advanced tumor stages. Functional assays revealed that both UCA1 knockdown and miR-28-5p overexpression could inhibit colon cancer cell growth and migration. Further mechanistic studies indicated that UCA1 knockdown played tumor suppressive roles in SW480 and HT116 cells through binding with miR-28-5p. We also, for the first time, identified HOXB3 as the target gene of miR-28-5p and that HOXB3 overexpression could mediate the functions of UCA1 in cell proliferation and migration of colon cancer cells. In conclusion, our data provided evidence for the regulatory network of UCA1/miR-28-5p/HOXB3 in colon cancer, suggesting that UCA1, miR-28-5p, and HOXB3 are the potential targets for colon cancer therapy.     

miR-340通过靶向GRP78促进结直肠癌细胞凋亡并抑制其增殖、迁移和侵袭

miR-340能够促进癌细胞的增殖和侵袭,但是在结直肠癌中miR-340如何调控癌症的发生与发展鲜有报道.本研究探究miR-340在结直肠癌细胞中的生物学功能和靶基因调控机制.首先通过RT-qPCR检测不同的结直肠癌细胞株中miR-340的表达水平,再利用过表达和抑制miR-340,分别转染COLO-205细胞,以CC...     

Role of MicroRNA 30a Targeting Insulin Receptor Substrate 2 in Colorectal Tumorigenesis

MicroRNAs (miRNAs) are dysregulated in many types of malignant diseases, including colorectal cancer. miRNA 30a (miR-30a) is a member of the miR-30 family and has been implicated in many types of cancers. In this study, we determined the expression of miR-30a in human colon cancer tissues and cell lines. miR-30a was found to be significantly downregulated in both the tissues and cell lines. Furthermore, overexpression of miR-30a inhibited, while silencing of miR-30a promoted, cell proliferation, migration, and invasion in vitro. Consistently, stable overexpression of miR-30a suppressed the growth of colon cancer cell xenografts in vivo. Moreover, bioinformatic algorithms and luciferase reporter assays revealed that insulin receptor substrate 2 (IRS2) is a direct target of miR-30a. Further functional studies suggested that repression of IRS2 by miR-30a partially mediated the tumor suppressor effect of miR-30a. In addition, miR-30a inhibited constitutive phosphorylation of Akt by targeting IRS2. Additionally, clinicopathological analysis indicated that miR-30a has an inverse correlation with the staging in patients with colon cancer. Taken together, our study provides the first evidence that miR-30a suppressed colon cancer cell growth through inhibition of IRS2. Thus, miR-30a might serve as a promising therapeutic strategy for colon cancer treatment.     

Retracted: MicroRNA-204-3p represses colon cancer cells proliferation,migration, and invasion by targeting HMGA2

Colon cancer is a detrimental neoplasm of the digestive tract. MicroRNAs (miRNAs) as central regulators have been discovered in colon cancer. Nonetheless, the impact of miR-204-3p on colon cancer remains indistinct. The research attempted to uncover the impacts of miR-204-3p on colon cancer cells growth, migration, and invasion. miR-204-3p expression level in colon cancer tissues and diverse colon cancer cell lines were testified by the quantitative real-time polymerase chain reaction. Exploration of the impacts of miR-204-3p on cell growth, migration, invasion, and their associated factors through assessment of CCK-8, flow cytometry, Transwell, and western blot, respectively. High mobility group AT-hook 2 (HMGA2) expression was then detected in Caco-2 cells after miR-204-3p mimic and inhibitor transfection, additionally dual-luciferase activity was implemented to further uncover the correlation between HMGA2 and miR-204-3p. The impact of HMGA2 on Caco-2 cell growth, migration, and invasion was finally assessed. We found that repression of miR-204-3p was discovered in colon cancer tissues and HCT116, SW480, Caco-2, HT29 and SW620 cell lines. MiR-204-3p overexpression mitigated Coca-2 cell viability, facilitated apoptosis, simultaneously adjusted CyclinD1 and cleaved caspase-3 expression. Cell migration, invasion, and the associated factors were all suppressed by miR-204-3p overexpression. Reduction of HMGA2 was presented in Caco-2 cells with miR-204-3p mimic transfection, and HMGA2 was predicated to be a target gene of miR-204-3p. Besides, HMGA2 silence showed the inhibitory effect on Caco-2 cells growth, migration, and invasion. In conclusion, miR-204-3p repressed colon cancer cell growth, migration, and invasion through targeting HMGA2.     

miR-125a regulates HAS1 and inhibits the proliferation,invasion and metastasis by targeting STAT3 in non–small cell lung cancer cells

MicroRNA-125a (miR-125a) is related to the occurrence, development, and prognosis of various cancers according to relevant reports. However, its function role and mechanism in non–small cell lung cancer (NSCLC) is yet to be explored. Herein, we investigated the role and preliminary mechanism of miR-125a in NSCLC. First, miR-125a was noticeably downregulated in NSCLC tissues in contrast to adjacent normal tissues through the real-time quantitative polymerase chain reaction (RT-qPCR) assay. The inverted result was observed on the STAT3 and HAS1 expressions. Moreover, miR-125a was expressed at highest level in A549 among four human NSCLC cell lines. Second, functional studies indicated miR-125a restrained proliferation, invasion, migration, metastasis, and advocated apoptosis of NSCLC cells, but had no obvious effect on cell cycle. Next, results indicated that a target of miR-125a was STAT3 on the basis of prediction and confirmation by the dual-luciferase reporter assay. RT-qPCR and Western blot assays displayed that miR-125a overexpression conspicuously constrained STAT3 expression at messenger RNA and protein levels. Finally, the binding between HAS1 promoter region and STAT3 was predicted by PROMO database analysis and verified by chromatin immunoprecipitation assay, suggesting that STAT3 was bound with the HAS1 promoter regions. STAT3 overexpression exerted positive effects on HAS1 expression at protein and mRNA levels. Additionally, HAS1-related functional studies illustrated HAS1 pronouncedly suppressed the proliferative, invasive, and migratory potential of NSCLC cells in vitro. Collectively, our findings demonstrated that miR-125a prohibited the proliferation, invasion, and migration of NSCLC cells by HAS1 expression reduction as a result of inhibiting STAT3 expression in NSCLC. This study indicated that miR-125a might be of potential or value for NSCLC treatment.     

Effects of microRNA-513b on cell proliferation,apoptosis, invasion,and migration by targeting HMGB3 through regulation of mTOR signaling pathway in non-small-cell lung cancer

This study aimed to explore the underlying mechanism of miR-513b and HMGB3 in regulating non-small-cell lung cancer (NSCLC). NSCLC tumor, adjacent tissues, and cell lines were extracted, and the expression of miR-513b and HMGB3 were determined by quantitative real-time polymerase chain reaction (RT-qPCR) and western blot analysis. Then, miR-513b was overexpressed in NSCLC cell, and the proliferation, migration, invasion, and apoptosis of cells were determined by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), wound healing, transwell, and flow cytometry, respectively. Regulatory relationship between miR-513b and HMGB3 was determined using luciferase activity reporter assay. Lastly, HMGB3 and/or miR-513b were overexpressed in NSCLC cells, and the proliferation, migration, invasion, and apoptosis of cells were determined. Compared with the controls, the expression of miR-513b was significantly downregulated in the NSCLC tissues and cells lines by RT-qPCR ( p < 0.05). However, the expression of HMGB3 was significantly downregulated at both messenger RNA and protein levels ( p < 0.05). Overexpression of miR-513b could significantly inhibit the proliferation, invasion, migration, and promote apoptosis of NSCLC cells ( p < 0.05). HMGB3 was a target of miR-513b, and overexpression of HMGB3 could obviously reverse the effect of miR-513 on the proliferation, invasion, migration, and apoptosis of NSCLC cells ( p < 0.05). The present results could suggest miR-513b was downregulated in NSCLC and could regulate the proliferation, invasion, migration, and apoptosis of NSCLC cells via HMGB3.     

Oncogenic miRNA-182-5p Targets Smad4 and RECK in Human Bladder Cancer

Onco-miR-182-5p has been reported to be over-expressed in bladder cancer (BC) tissues however a detailed functional analysis of miR-182-5p has not been carried out in BC. Therefore the purpose of this study was to: 1. conduct a functional analysis of miR-182-5p in bladder cancer, 2. assess its usefulness as a tumor marker, 3. identify miR-182-5p target genes in BC. Initially we found that miR-182-5p expression was significantly higher in bladder cancer compared to normal tissues and high miR-182-5p expression was associated with shorter overall survival in BC patients. To study the functional significance of miR-182-5p, we over-expressed miR-182-5p with miR-182-5p precursor and observed that cell proliferation, migration and invasion abilities were increased in BC cells. However cell apoptosis was inhibited by miR-182-5p. We also identified Smad4 and RECK as potential target genes of miR-182-5p using several algorithms. 3′UTR luciferase activity of these target genes was significantly decreased and protein expression of these target genes was significantly up-regulated in miR-182-5p inhibitor transfected bladder cancer cells. MiR-182-5p also increased nuclear beta-catenin expression and while Smad4 repressed nuclear beta-catenin expression. In conclusion, our data suggests that miR-182-5p plays an important role as an oncogene by knocking down RECK and Smad4, resulting in activation of the Wnt-beta-catenin signaling pathway in bladder cancer.     

MiR-124 Suppresses Growth of Human Colorectal Cancer by Inhibiting STAT3

Emerging evidence indicate that microRNAs (miRNAs) may play important roles in cancer. Aberrant expression of miRNAs has been frequently identified in different human malignancies, including colorectal cancer (CRC). However, the mechanism by which deregulated miRNAs impact the development of CRC remains largely elusive. In this study, we show that miR-124 is significantly down-regulated in CRC compared to adjacent non-tumor colorectal tissues. MiR-124 suppresses the expression of STAT3 by directly binding to its 3′-untranslated region (3′-UTR). Overexpression of miR-124 led to increased apoptosis of CRC cells and reduced tumor growth in vitro and in vivo. Knocking down STAT3 expression by specific siRNA suppressed the growth of CRC cells in vitro and in vivo, resembling that of miR-124 overexpression. Moreover, overexpression of STAT3 in miR-124-transfected CRC cells effectively rescued the inhibition of cell proliferation caused by miR-124. These data suggest that miR-124 serves as a tumor suppressor by targeting STAT3, and call for the use of miR-124 as a potential therapeutic tool for CRC, where STAT3 is often hyper-activated.     

MicroRNA-524-5p suppresses the progression of papillary thyroid carcinoma cells via targeting on FOXE1 and ITGA3 in cell autophagy and cycling pathways

MicroRNAs are beneficial for cancer therapy as they can simultaneously downregulate multiple targets involved in diverse biological pathways related to tumor development. In papillary thyroid cancer, many microRNAs were identified as differentially expressed factors in tumor tissues. In another way, recent studies revealed cell proliferation, cell cycling, apoptosis, and autophagy are critical pathways controlling papillary thyroid cancer development and progression. As miR-524-5p was approved as a cancer suppressor targeting multiple genes in several types of cancer cells, this study aims to characterize the role of miR-524-5p in the thyroid cancer cell. The expression of miR-524-5p was decreased in the papillary thyroid cancer tissues and cell lines, while forkhead box E1 (FOXE1) and ITGA3 were increased. In the clinical case, expression of miR-524-5p, FOXE1, and ITGA3 were significantly correlated with papillary thyroid cancer development and progression. FOXE1 and ITGA3 were approved as direct targets of miR-524-5p. miR-524-5p could inhibit papillary thyroid cancer cell viability, migration, invasion, and apoptosis through targeting FOXE1 and ITGA3. Cell cycling and autophagy pathways were disturbed by downregulation of FOXE1 and ITGA3, respectively. Collectively, miR-524-5p targeting on FOXE1 and ITGA3 prevents thyroid cancer progression through different pathways including cell cycling and autophagy.     

Convallatoxin promotes apoptosis and inhibits proliferation and angiogenesis through crosstalk between JAK2/STAT3 (T705) and mTOR/STAT3 (S727) signaling pathways in colorectal cancer

BackgroundAberrant activation of STAT3 is frequently encountered and promotes survival, cellular proliferation, migration, invasion and angiogenesis in tumor cell. Convallatoxin, triterpenoid ingredient, exhibits anticancer pharmacological properties.PurposeIn this work, we investigated the anticancer potential of convallatoxin and explored whether convallatoxin mediates its effect through interference with the STAT3 activation in colorectal cancer cells.MethodsIn vitro, the underlying mechanisms of convallatoxin at inhibiting STAT3 activation were investigated by homology modeling and molecular docking, luciferase reporter assay, MTT assay, RT-PCR, Western blotting and immunofluorescence assays. Changes in cellular proliferation, apoptosis, migration, invasion and angiogenesis were analyzed by EdU labeling assay, colony formation assay, flow cytometry assay, wound-healing assay, matrigel transwell invasion assay and tube formation assays. And in vivo, antitumor activity of convallatoxin was assessed in a murine xenograft model of HCT116 cells.ResultsConvallatoxin decreased the viability of colorectal cancer lines. Moreover, convallatoxin reduced the P-STAT3 (T705) via the JAK1, JAK2, and Src pathways and inhibited serine-727 phosphorylation of STAT3 via the PI3K-AKT-mTOR-STAT3 pathways in colorectal cancer cells. Interestingly, we discovered the crosstalk between mTOR and JAK2 in mTOR/STAT3 and JAK/STAT3 pathways, which collaboratively regulated STAT3 activation and convallatoxin play a role in it. Convallatoxin also downregulated the expression of target genes involved cell survival (e.g., Survivin, Bcl-xl, Bcl-2), proliferation (e.g., Cyclin D1), metastasis (e.g., MMP-9), and angiogenesis (e.g., VEGF). Indeed, we found that convallatoxin inhibited tube formation, migration, and invasion of endothelial cells, and inhibited the proliferation. Finally, in vivo observations were confirmed by showing antitumor activity of convallatoxin in a murine xenograft model.ConclusionThe result of the current study show that convallatoxin promotes apoptosis and inhibits proliferation and angiogenesis through crosstalk between JAK2/STAT3 (T705) and mTOR/STAT3 (S727) signaling pathways in colorectal cancer cells and indicate that convallatoxin could be a valuable candidate for the development of colorectal cancer therapeutic.     

MicroRNA-137 Contributes to Dampened Tumorigenesis in Human Gastric Cancer by Targeting AKT2

MiRNAs play important roles in tumorigenesis. This study focused on exploring the effects and regulation mechanism of miRNA-137 on the biological behaviors of gastric cancer. Total RNA was extracted from tissues of 100 patients with gastric cancer and from four gastric cancer cell lines. Expression of miR-137 was detected by real-time PCR from 100 patients. The effects of miR-137 overexpression on gastric cancer cells’ proliferation, apoptosis, migration and invasion ability were investigated in vitro and in vivo. The target gene of miR-137 was predicted by Targetscan on line software, screened by dual luciferase reporter gene assay and demonstrated by western blot. As a result, the expression of miR-137 was significant reduced in gastric cancer cell line HGC-27, HGC-803, SGC-7901 and MKN-45 as well as in gastric cancer tissues compared with GES-1 cell or matched adjacent non-neoplastic tissues (p<0.001). The re-introduction of miR-137 into gastric cancer cells was able to inhibit cell proliferation, migration and invasion. The in vivo experiments demonstrated that the miR-137 overexpression can reduce the gastric cancer cell proliferation and metastasis. Bioinformatic and western blot analysis indicated that the miR-137 acted as tumor suppressor roles on gastric cancer cells through targeting AKT2 and further affecting the Bad and GSK-3β. In conclusion, the miR-137 which is frequently down-regulated in gastric cancer is potentially involved in gastric cancer tumorigenesis and metastasis by regulating AKT2 related signal pathways.     

CircTP53 promotes colorectal cancer by acting as a miR-876-3p sponge to increase cyclin-dependent kinase-like 3 expression

According to ceRNA theory, circular RNAs could regulate certain protein expression through targeting corresponding microRNAs to affect the progression of multiple diseases, including colorectal cancer. CircTP53 (hsa_circ_0107702), highly expressed in thyroid cancer tissues, could promote the proliferation of thyroid cancer. However, the function of circTP53 in colorectal cancer is still unclear. In our study, we found circTP53 was significantly up-regulated in colorectal cancer tissues from patients and in colorectal cell lines. Next, using colorectal cell lines, we confirmed that circTP53 promoted the proliferation, migration and invasion, and reduced the apoptotic rate. Furthermore, through bioinformatics analysis and experimental confirmation, we found circTP53 functioned as the sponge of miR-876-3p, and miR-876-3p reversed the phenotype of circTP53 on the facilitation of colorectal cancer. Additionally, we found circTP53 promoted the progression of colorectal cancer by elevating the expression of CDKL3. At last, we suggested that circTP53 knockdown could inhibit colorectal cancer progression in vivo. In conclusion, circTP53 was highly expressed in colorectal cancer tissues, and promoted colorectal cancer progression via modulating miR-876-3p/CDKL3 axis.     

MicroRNA-384 inhibits nasopharyngeal carcinoma growth and metastasis via binding to Smad5 and suppressing the Wnt/β-catenin axis

Nasopharyngeal carcinoma (NPC) is a major otorhinolaryngological disease with limited effective therapeutic options. This work focused on the function of microRNA-384 (miR-384) on the NPC pathogenesis and the molecules involved. miR-384 expression in cancer tissues and cells was detected. Gain- and loss-of-functions of miR-384 were performed to identify its role in NPC progression. The target mRNA of miR-384 was predicted on an online system and validated through a luciferase reporter assay. The activity of Wnt/β-catenin signaling was detected. Consequently, miR-384 was found to be poorly expressed in NPC tissues and cell lines and was linked to unfavorable survival rates in patients. Overexpression of miR-384 in 6-10B cells suppressed growth, migration, invasion and resistance to apoptosis of cells, but inverse trends were presented in C6661 cells where miR-384 was downregulated. miR-384 targeted Smad5 mRNA. Upregulation of Smad5 counteracted the roles of miR-384 mimic in cells. The NPC-inhibiting effects of miR-384 mimic were also blocked by Wnt/β-catenin activation. To conclude, miR-384 targets Smad5 and inactivates the Wnt/β-catenin pathway, which exerts a suppressing role in NPC cell behaviors as well as tumor growth in vivo. The findings may offer novel thoughts into NPC therapy.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10616-021-00458-3.     

MicroRNA-320a suppresses human colon cancer cell proliferation by directly targeting β-catenin

Recent profile studies of microRNA (miRNA) expression have documented a deregulation of miRNA (miR-320a) in human colorectal carcinoma. However, its expression pattern and underlying mechanisms in the development and progression of colorectal carcinoma has not been elucidated clearly. Here, we performed real-time PCR to examine the expression levels of miR-320a in colon cancer cell lines and tumor tissues. And then, we investigated its biological functions in colon cancer cells by a gain of functional strategy. Further more, by the combinational approaches of bioinformatics and experimental validation, we confirmed target associations of miR-320a in colorectal carcinoma. Our results showed that miR-320a was frequently downregulated in cancer cell lines and colon cancer tissues. And we demonstrated that miR-320a restoration inhibited colon cancer cell proliferation and β-catenin, a functionally oncogenic molecule was a direct target gene of miR-320a. Finally, the data of real-time PCR showed the reciprocal relationship between miR-320a and β-catenin's downstream genes in colon cancer tissues. These findings indicate that miR-320a suppresses the growth of colon cancer cells by directly targeting β-catenin, suggesting its application in prognosis prediction and cancer treatment.     

下调lncRNA MCF2L-AS1靶向miR-33b-5p抑制胃癌细胞增殖、迁移、侵袭并促进凋亡

摘要 目的：探讨lncRNA MCF2L-AS1对胃癌细胞恶性生物学行为的影响及分子机制。方法：选取45例胃癌患者的癌组织及癌旁正常组织,或培养胃黏膜上皮细胞GES-1、胃癌细胞HGC-27,采用RT-qPCR检测MCF2L-AS1和miR-33b-5p的表达水平。采用双荧光素酶报告实验检测MCF2L-AS1和miR-33b-5p的靶向关系。将HGC-27细胞分为si-NC组、si-MCF2L-AS1组、mimic NC组、miR-33b-5p mimic组、si-MCF2L-AS1+inhibitor NC组、si-MCF2L-AS1+miR-33b-5p inhibitor组,分别转染si-NC、si-MCF2L-AS1、mimic NC、miR-33b-5p mimic或共转染si-MCF2L-AS1+inhibitor NC、si-MCF2L-AS1+miR-33b-5p inhibitor。采用MTT实验检测细胞增殖情况,流式细胞术检测细胞凋亡率,克隆形成实验检测细胞克隆形成数,Transwell实验检测迁移和侵袭细胞数。结果：与癌旁正常组织或GES-1细胞相比,胃癌组织或HGC-27细胞中MCF2L-AS1表达水平升高、miR-33b-5p表达水平降低,差异均有统计学意义（P<0.05）。MCF2L-AS1可靶向调控miR-33b-5p。下调MCF2L-AS1或过表达miR-33b-5p,miR-33b-5p表达水平升高,HGC-27细胞凋亡率升高,但细胞增殖、克隆形成数、迁移和侵袭数均减少,差异均有统计学意义（P<0.05）。抑制miR-33b-5p可减弱下调MCF2L-AS1对HGC-27细胞的生物学作用。结论：下调MCF2L-AS1通过上调miR-33b-5p抑制胃癌细胞增殖、迁移、侵袭并促进凋亡;MCF2L-AS1通过靶向调控miR-33b-5p表达进而参与胃癌细胞的恶性生物学行为。     

miR-18a Inhibits CDC42 and Plays a Tumour Suppressor Role in Colorectal Cancer Cells

The miR-17-92 cluster of microRNAs is elevated in colorectal cancer, and has a causative role in cancer development. Of the six miR-17-92 cluster members, miR-19a and b in particular are key promoters of cancer development and cell proliferation, while preliminary evidence suggests that miR-18a may act in opposition to other cluster members to decrease cell proliferation. It was hypothesised that miR-18a may have a homeostatic function in helping to contain the oncogenic effect of the entire miR-17-92 cluster, and that elevated miR-17-92 cluster activity without a corresponding increase in miR-18a may promote colorectal tumour progression. In colorectal cancer samples and corresponding normal colorectal mucosa, miR-18a displayed lower overall expression than other miR-17-92 cluster members. miR-18a was shown to have an opposing role to other miR-17-92 cluster members, in particular the key oncogenic miRNAs, miR-19a and b. Transfection of HCT116 and LIM1215 colorectal cancer cell lines with miR-18a mimics decreased proliferation, while a miR-18a inhibitor increased proliferation. miR-18a was also responsible for decreasing cell migration, altering cell morphology, inducing G1/S phase cell cycle arrest, increasing apoptosis, and enhancing the action of a pro-apoptotic agent. CDC42, a mediator of the PI3K pathway, was identified as a novel miR-18a target. Overexpression of miR-18a reduced CDC42 expression, and a luciferase assay confirmed that miR-18a directly targets the 3′UTR of CDC42. miR-18a mimics had a similar effect on proliferation as a small molecule inhibitor of CDC42. Inhibition of CDC42 expression is likely to be a key mechanism by which miR-18a impairs cancer cell growth, with a target protector experiment revealing miR-18a influences proliferation via direct inhibition of CDC42. Inhibition of CCND1 by miR-18a may also assist in this growth-suppression effect. The homeostatic function of miR-18a within the miR-17-92 cluster in colorectal cancer cells may be achieved through suppression of CDC42 and the PI3K pathway.