Long noncoding RNA MAPKAPK5‐AS1 promotes colorectal cancer proliferation by partly silencing p21 expression

Colorectal cancer (CRC) is the third most common malignancy in the world, and long noncoding RNA (lncRNA) plays a critical role in carcinogenesis. Here, we report a novel lncRNA, MAPKAPK5‐AS1, that acts as a critical oncogene in CRC. In addition, we attempted to explore the functions of MAPKAPK5‐AS1 on tumor progression in vitro and in vivo. Quantitative RT‐PCR was used to examine the expression of MAPKAPK5‐AS1 in CRC tissues and cells. Expression of MAPKAPK5‐AS1 was significantly upregulated in 50 CRC tissues, and increased expression of MAPKAPK5‐AS1 was found to be associated with greater tumor size and advanced pathological stage in CRC patients. Knockdown of MAPKAPK5‐AS1 significantly inhibited proliferation and caused apoptosis in CRC cells. We also found that p21 is a target of MAPKAPK5‐AS1. In addition, we are the first to report that MAPKAPK5‐AS1 plays a carcinogenic role in CRC. MAPKAPK5‐AS1 is a novel prognostic biomarker and a potential therapeutic candidate for CRC cancer.     

Long noncoding RNA OVAAL enhances nucleotide synthesis through pyruvate carboxylase to promote 5‐fluorouracil resistance in gastric cancer

5‐Fluorouracil (5‐FU) is widely used in gastric cancer treatment, yet 5‐FU resistance remains an important clinical challenge. We established a model based on five long noncoding RNAs (lncRNA) to effectively assess the prognosis of gastric cancer patients; among them, lncRNA OVAAL was markedly upregulated in gastric cancer and associated with poor prognosis and 5‐FU resistance. In vitro and in vivo assays confirmed that OVAAL promoted proliferation and 5‐FU resistance of gastric cancer cells. Mechanistically, OVAAL bound with pyruvate carboxylase (PC) and stabilized PC from HSC70/CHIP‐mediated ubiquitination and degradation. OVAAL knockdown reduced intracellular levels of oxaloacetate and aspartate, and the subsequent pyrimidine synthesis, which could be rescued by PC overexpression. Moreover, OVAAL knockdown increased sensitivity to 5‐FU treatment, which could be reversed by PC overexpression or repletion of oxaloacetate, aspartate, or uridine. OVAAL overexpression enhanced pyrimidine synthesis to promote proliferation and 5‐FU resistance of gastric cancer cells, which could be abolished by PC knockdown. Thus, OVAAL promoted gastric cancer cell proliferation and induced 5‐FU resistance by enhancing pyrimidine biosynthesis to antagonize 5‐FU induced thymidylate synthase dysfunction. Targeting OVAAL‐mediated nucleotide metabolic reprograming would be a promising strategy to overcome chemoresistance in gastric cancer.     

长链非编码RNA HCP5通过调控凋亡通路促进三阴性乳腺癌的研究

目的 探讨长链非编码RNA(lncRNA)HCP5在三阴性乳腺癌中的作用及其机制。方法 通过qPCR分析HCP5在乳腺癌细胞系和正常乳腺细胞系中的mRNA含量,RNA Scope方法分析HCP5在乳腺组织和癌组织中的表达;通过CCK-8实验和细胞存活/死亡实验分析敲低HCP5对三阴性乳腺癌细胞增殖能力的影响;裸鼠体内实验分析敲低HCP5对三阴性乳腺癌细胞成瘤能力的影响;抗体芯片技术分析敲低HCP5影响凋亡通路中BIRC3和Caspase-3蛋白的表达。结果 与正常乳腺细胞和其他类型乳腺癌细胞相比,HCP5在三阴性乳腺癌细胞系中表达上调(P＜0.05),与正常乳腺组织和其他亚型乳腺癌组织相比,HCP5在三阴性乳腺癌组织中表达上调(P＜0.05);与对照组相比,HCP5敲低组三阴性乳腺癌细胞增殖减少、凋亡增加,且原位移植瘤的生长受到抑制(P＜0.01);敲低HCP5引起凋亡通路中凋亡抑制因子BIRC3表达量降低、Caspase-3表达增加,差异具有统计学意义(P＜0.05),对MAPK信号通路蛋白的影响组间差异无统计学意义。结论 lncRNA HCP5通过调控细胞凋亡途径促进三阴性乳腺癌的恶性进展。     

Down-regulation of KLF5 in cancer-associated fibroblasts inhibit gastric cancer cells progression by CCL5/CCR5 axis

It was well known that cancer-associated fibroblasts (CAFs) were an essential factor in tumor progression. However, the actual mechanism of stromal fibroblasts activation and tumor promoting effects remain unclear. Here, we showed that KLF5 expression was more frequently observed in gastric cancer-associated fibroblasts compared with normal mucosal fibroblasts. Moreover, KLF5 expression in tumor stroma was closely associated with clinicopathological features such as tumor size, invasion depth, cell grade and lymph node metastasis, as well as poor prognosis in patients with gastric cancer. In addition, we further demonstrated that KLF5-regulating CAFs affect gastric cancer cells progression by CCL5 secretion and activation of CCR5. Taken together, we concluded that KLF5 expression in gastric cancer-associated fibroblasts contribute to poor survival and promote cancer cells progression by activation of CCL5/CCR5 axis, which suggesting that KLF5 in CAFs might be considered as a promising target for the treatment of gastric cancer.     

Tumor-derived CCL5 does not contribute to breast cancer progression

Besides functioning as a chemotactic factor, CCL5 has been associated with progression of disease in women with breast cancer, immune modulation and metastasis. Here we asked whether CCL5 produced by tumor cells contributed to growth or metastasis of breast cancer. For this purpose, we used two murine mammary carcinomas, the 4T1 tumor which is metastatic and constitutively expresses CCL5, and the 168 tumor which is not metastatic and does not constitutively express CCL5. RNA interference was used to inhibit CCL5 expression from the 4T1 tumor, and a CCL5 transgene was used to express CCL5 by the 168 tumor. Six different clones of 4T1 that exhibited stable reduction in CCL5 expression, and three different clones of 168 that exhibited stable CCL5 expression were compared to the parental tumors and vector transfected controls. Significantly, in both models, tumor-derived CCL5 expression did not correlate with MHC expression, growth rate, or metastatic ability of the tumors. These results show that tumor-derived CCL5 expression alone does not make a significant contribution to breast cancer progression.     

Long noncoding RNA SOX2OT promotes the proliferation of pancreatic cancer by binding to FUS

Pancreatic ductal adenocarcinoma (PDAC) is one of the most malignant tumors has one of the worst prognoses, and the role of long noncoding RNAs (lncRNAs) in the biological and pathological processes of pancreatic cancer, including tumor cell proliferation, is a popular topic in tumor research. Our previous study revealed the correlation between high levels of the lncRNA-SOX2OT (SOX2OT) with poor survival outcomes. Cell Counting Kit-8, EdU, Flow cytometry and Colony formation assays as well as Xenograft growth of PDAC cells in mice were used for the detection of PDAC cells proliferation progression. Fluorescence in situ hybridization, RNA-binding protein pulldown and RNA immunoprecipitation assays were also used to identify the putative mechanisms of SOX2OT participating in the tumor progression. SOX2OT and its potential downstream targets were verified by Western blot and quantitative real-time polymerase chain reaction (qRT-PCR). SOX2OT was confirmed to promote the proliferation of PDAC cells. It was found to directly physically bind to FUS and we also demonstrated that FUS protein stability was affected by binding with SOX2OT and FUS could suppressed PDAC tumor by regulating cell cycle-associated factors CCND1 and p27. Our findings suggest that SOX2OT may act as a tumor promoter in PDAC through physically binding FUS and regulating its downstream cell cycle-associated factors CCND1 and p27. It may serve as an effective target for antitumor treatment for pancreatic cancer.     

hsa_circ_0003410 promotes hepatocellular carcinoma progression by increasing the ratio of M2/M1 macrophages through the miR‐139‐3p/CCL5 axis

Noncoding RNAs have been verified to regulate the infiltration of macrophages to accelerate tumor biological progression, however the regulation of macrophages by circular RNAs in hepatocellular carcinoma (HCC) remains unresolved. Using high‐throughput RNA sequencing, we demonstrated that hsa_circ_0003410 was clearly upregulated in HCC. 5‐Ethynyl‐2′‐deoxyuridine and transwell assays showed that hsa_circ_0003410 facilitated the proliferation and migration of HCC cells in vitro. We knocked down the expression of hsa_circ_0003410 in HepG2 cells and performed next‐generation sequencing to determine possible target genes of hsa_circ_0003410. Kyoto Encyclopedia of Genes and Genomes analysis revealed that different genes were mainly enriched in immune‐related pathways. Mechanistically, we identified CCL5 as the target gene of hsa_circ_0003410. RNA‐FISH showed the co‐expression of hsa_circ_0003410 and CCL5. Western blot and ELISA also verified that hsa_circ_0003410 could upregulate the expression of CCL5 protein. Flow cytometry and immunofluorescence assays indicated that CCL5 activated and recruited M2 macrophages and increased the ratio of M2/M1 macrophages to promote the progression of HCC. Animal experiments in vitro also confirmed our results. Taken together, our experiments revealed that noncoding RNAs play a critical role in the HCC microenvironment and can be considered as markers for the diagnosis and prognosis of HCC.     

Long non‐coding RNA RACGAP1P promotes breast cancer invasion and metastasis via miR‐345‐5p/RACGAP1‐mediated mitochondrial fission

Long non‐coding RNAs (lncRNAs) are emerging as key molecules in various cancers, yet their potential roles in the pathogenesis of breast cancer are not fully understood. Herein, using microarray analysis, we revealed that the lncRNA RACGAP1P, the pseudogene of Rac GTPase activating protein 1 (RACGAP1), was up‐regulated in breast cancer tissues. Its high expression was confirmed in 25 pairs of breast cancer tissues and 8 breast cell lines by qRT‐PCR. Subsequently, we found that RACGAP1P expression was positively correlated with lymph node metastasis, distant metastasis, TNM stage, and shorter survival time in 102 breast cancer patients. Then, in vitro and in vivo experiments were designed to investigate the biological function and regulatory mechanism of RACGAP1P in breast cancer cell lines. Overexpression of RACGAP1P in MDA‐MB‐231 and MCF7 breast cell lines increased their invasive ability and enhanced their mitochondrial fission. Conversely, inhibition of mitochondrial fission by Mdivi‐1 could reduce the invasive ability of RACGAP1P‐overexpressing cell lines. Furthermore, the promotion of mitochondrial fission by RACGAP1P depended on its competitive binding with miR‐345‐5p against its parental gene RACGAP1, leading to the activation of dynamin‐related protein 1 (Drp1). In conclusion, lncRNA RACGAP1P promotes breast cancer invasion and metastasis via miR‐345‐5p/RACGAP1 pathway‐mediated mitochondrial fission.

Abbreviations

CDS

coding sequence

ceRNAs

competitive endogenous RNAs

Drp1

dynamin‐related protein 1

FFPE

formalin‐fixed paraffin‐embedded

lncRNAs

long non‐coding RNAs

miRNAs

microRNAs

RACGAP1

Rac GTPase activating protein 1

TCGA

The Cancer Genome Atlas

     

Prognostic significance of expression of CCL5/RANTES receptors in patients with gastric cancer

BACKGROUND AND OBJECTIVES: The clinical significance of CCL5 has been reported in several malignancies. In this study, we examined the prognostic impact of serum CCL5 levels and the expression of CCL5 receptors on tumor cells in patients with gastric cancer. METHODS: Serum CCL5 levels in patients with gastric cancer were measured by enzyme-linked immunoabsorbent assay. Immunohistochemical staining of three chemokine receptors, CCR1, CCR3, and CCR5, which are known as CCL5 receptors, was performed in gastric cancer tissue. RESULTS: We found that serum CCL5 levels themselves had no impact on survival; however, higher serum CCL5 concentrations were associated with more advanced disease. Eighty-six (41%), 48 (23%), and 60 patients (28%) showed positive expression of CCR1, CCR3, and CCR5, respectively, on gastric cancer cells. Among the patients who underwent curative resection for stages II-IV disease, patients with positive CCR3 expression had significantly lower survival rates compared to those with negative CCR3 expression. Unlike CCR1, positive CCR5 expression was also associated with poorer prognosis. Multivariate analysis revealed that expression of CCR3 and/or CCR5 was an independent prognostic factor. CONCLUSIONS: Tumor expression of CCR3 and/or CCR5 (receptors for CCL5) is associated with a lower survival rate in patients with gastric cancer.