Down-regulation of CASC2 contributes to cisplatin resistance in gastric cancer by sponging miR-19a

Exosomal miR-19a derived from melanoma cell promotes the vemurafenib resistance of malignant melanoma through directly targeting LRIG1 to reactivate AKT and MAPK pathway

Exosomes derived from neighboring v-raf murine sarcoma viral oncogene homolog B1 inhibitor (BRAFi)-resistant melanoma cells mediate the formation of resistance in melanoma cells sensitive to BRAFi. The function and molecular mechanisms of exosomal miRNA in BRAFi resistance of melanoma have not been studied. We found that the expression of miR-19a in BRAFi resistant melanoma cells was significantly higher than that in sensitive cells, and miR-19a contributes to the resistance of melanoma cells to BRAFi by targeting immunoglobulin-like domains protein 1 (LRIG1). miR-19a was highly enriched in exosomes secreted from BRAFi resistant melanoma cells, and these exosomal miR-19a promote the spread of BRAFi resistant. The reactivation of Protein kinase B (AKT) and mitogen-activated protein kinase (MAPK) pathways is the main reason for the BRAFi resistant of melanoma cells. We demonstrated that exosomal miR-19a derived from melanoma cell promotes the formation and spread of BRAFi resistant in melanoma through targeting LRIG1 to reactivate AKT and MAPK pathway. Therefore, miR-19a may serve as a potential therapeutic target in melanoma patients with acquired drug resistance.

Long Non-Coding RNAs in Drug Resistance of Gastric Cancer: Complex Mechanisms and Potential Clinical Applications

Gastric cancer (GC) ranks as the third most prevalent malignancy and a leading cause of cancer-related mortality worldwide. However, the majority of patients with GC are diagnosed at an advanced stage, highlighting the urgent need for effective perioperative and postoperative chemotherapy to prevent relapse and metastasis. The current treatment strategies have limited overall efficacy because of intrinsic or acquired drug resistance. Recent evidence suggests that dysregulated long non-coding RNAs (lncRNAs) play a significant role in mediating drug resistance in GC. Therefore, there is an imperative to explore novel molecular mechanisms underlying drug resistance in order to overcome this challenging issue. With advancements in deep transcriptome sequencing technology, lncRNAs-once considered transcriptional noise-have garnered widespread attention as potential regulators of carcinogenesis, including tumor cell proliferation, metastasis, and sensitivity to chemo- or radiotherapy through multiple regulatory mechanisms. In light of these findings, we aim to review the mechanisms by which lncRNAs contribute to drug therapy resistance in GC with the goal of providing new insights and breakthroughs toward overcoming this formidable obstacle.

Long non-coding RNA (lncRNA) PVT1 in drug resistance of cancers: Focus on pathological mechanisms

According to estimates, cancer will be the leading cause of death globally in 2022, accounting for 9.6 million deaths. At present, the three main therapeutic modalities utilized to treat cancer are radiation therapy, chemotherapy, and surgery. However, during treatment, tumor cells resistant to chemotherapy may arise. Drug resistance remains a major oppose since it often leads to therapeutic failure. Furthermore, the term "acquired drug resistance" describes the situation where tumor cells already display drug resistance before undergoing chemotherapy. However, little is still known about the basic mechanisms underlying chemotherapy-induced drug resistance. The development of new technologies and bioinformatics has led to the discovery of additional genes associated with drug resistance. Long noncoding RNA plasmacytoma variant translocation 1 (PVT1) has been linked to an increased risk of cancer, according to a growing body of research. Apart from biological functions associated with cell division, development, pluripotency, and cell cycle, lncRNA PVT1 contributes significantly to the regulation of various aspects of genome function, such as transcription, splicing, and epigenetics. The article will address the mechanism by which lncRNA PVT1 influences drug resistance in cancer cells.

From carcinogenesis to therapeutic avenues: lncRNAs and mTOR crosstalk in lung cancer

Long non-coding RNAs (lncRNAs) have been demonstrated to have a crucial function in the modulation of the activity of genes, impacting a variety of homeostatic processes involving growth, survival, movement, and genomic consistency. Certain lncRNAs' aberrant expression has been linked to carcinogenesis, tumor growth, and therapeutic resistance. They are beneficial for the management of malignancies since they can function as cancer-causing or cancer-suppressing genes and behave as screening or prognosis indicators. The modulation of the tumor microenvironment, metabolic modification, and spread have all been linked to lncRNAs in lung cancer. Recent research has indicated that lncRNAs may interact with various mTOR signalling systems to control expression in lung cancer. Furthermore, the route can affect how lncRNAs are expressed. Emphasizing the function of lncRNAs as crucial participants in the mTOR pathway, the current review intends to examine the interactions between the mTOR cascade and the advancement of lung cancer. The article will shed light on the roles and processes of a few lncRNAs associated with the development of lung cancer, as well as their therapeutic prospects.

Non-coding RNA in cancer drug resistance: Underlying mechanisms and clinical applications

Cancer is one of the most frequently diagnosed malignant diseases worldwide, posing a serious, long-term threat to patients’ health and life. Systemic chemotherapy remains the first-line therapeutic approach for recurrent or metastatic cancer patients after surgery, with the potential to effectively extend patient survival. However, the development of drug resistance seriously limits the clinical efficiency of chemotherapy and ultimately results in treatment failure and patient death. A large number of studies have shown that non-coding RNAs (ncRNAs), particularly microRNAs, long non-coding RNAs, and circular RNAs, are widely involved in the regulation of cancer drug resistance. Their dysregulation contributes to the development of cancer drug resistance by modulating the expression of specific target genes involved in cellular apoptosis, autophagy, drug efflux, epithelial-to-mesenchymal transition (EMT), and cancer stem cells (CSCs). Moreover, some ncRNAs also possess great potential as efficient, specific biomarkers in diagnosis and prognosis as well as therapeutic targets in cancer patients. In this review, we summarize the recent findings on the emerging role and underlying mechanisms of ncRNAs involved in cancer drug resistance and focus on their clinical applications as biomarkers and therapeutic targets in cancer treatment. This information will be of great benefit to early diagnosis and prognostic assessments of cancer as well as the development of ncRNA-based therapeutic strategies for cancer patients.

Downregulation of LINC01857 Increases Sensitivity of Gastric Carcinoma Cells to Cisplatin

Background

The critical roles of long noncoding RNAs (lncRNAs) in the carcinogenesis and progression of cancers have been well documented. It was reported that lncRNAs were involved in chemotherapy resistance in various cancers. This study was aimed at clarifying the role of LINC01857 in cisplatin (DDP) resistance in gastric carcinoma (GC).

Methods

The Cancer Genome Atlas (TCGA) database was used to analyze the expression of LINC01857 in GC tissues and normal tissues. The expression of LINC01857 in GC cells and DDP-resistant GC cells was detected by qRT-PCR. Cell viability and IC50 value were evaluated using the MTT assay. Moreover, cell apoptosis, migration, and invasion were determined using flow cytometry and Transwell assays, respectively. The expression of apoptosis-related proteins was examined by western blot.

Results

TCGA database analysis revealed that LINC01857 expression was elevated in GC tissues compared with the normal tissues. qRT-PCR showed that the expression of LINC01857 was significantly higher in DDP-resistant cells than in GC and normal gastric cells. Knockdown of LINC01857 reduced cell viability in DDP-resistant cells. Moreover, LINC01857 downregulation promoted cell apoptosis and inhibited cell migration and invasion in DDP-resistant GC cells.

Conclusions

LINC01857 was highly expressed in GC. Additionally, LINC01857 knockdown could facilitate the sensitivity to DDP and apoptosis and repressed cell migration and invasion in DDP-resistant GC cells, which provided a novel therapeutic target for chemotherapy resistance of GC in clinical practice.

Curcumol enhances cisplatin sensitivity of gastric cancer: involvement of microRNA-7 and the nuclear factor-kappa B/snail family transcriptional repressor 1 axis

Cisplatin is a primary chemotherapeutic drug for gastric cancer (GC) patients, but the drug resistance remains the leading cause of treatment failure and high mortality. Curcumol is a bioactive sesquiterpenoid that has reportedly been linked to cisplatin sensitivity in GC. This study focuses on the exact functions of curcumol in the cisplatin sensitivity of GC cells and the molecules of action. The curcumol treatment reduced the viability and migration and enhanced cisplatin sensitivity of GC cells in a dose-dependent manner. Microarray analysis suggested that microRNA-7 (miR-7) was the most upregulated miRNA in GC cells after curcumol treatment. The Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis showed that the curcumol-affected genes, including the target genes of miR-7, were enriched in the nuclear factor-kappa B (NF-κB) pathway, whose activity was suppressed after curcumol treatment. miR-7 was found to target and suppress RELA proto-oncogene (RELA, also known as p65), a NF-κB subunit. Downregulation of miR-7 blocked the sensitizing effects of curcumol on cells to cisplatin and led to increased expression of NF-κB p65 and snail family transcriptional repressor 1 (SNAIL). Further downregulation of RELA enhanced, whereas upregulation of SNAIL suppressed the sensitivity again. In summary, this study suggests that curcumol sensitizes GC cells to cisplatin via miR-7 and the suppression of the NF-κB/SNAIL axis. The findings may offer new thoughts that curcumol in combination with cisplatin might be a useful strategy for GC management.

<em>miR-19a</em> targeting <em>CLCA4</em> to regulate the proliferation, migration, and invasion of colorectal cancer cells

The role of miR-19a in colorectal cancer (CRC), a devastating disease with high mortality and morbidity, remains controversial. In the present study, we show that the level of miR-19a is significantly higher in clinical CRC tissue samples than in paracancerous tissue samples, and significantly higher in CRC cells lines HT29, SW480, and CaCO2 than in the normal human colon mucosal epithelial cell line NCM460. miR-19a mimics and inhibitors were synthesized and validated. Overexpression of miR-19a mimics significantly promoted, while miR-19a inhibitors inhibited, the proliferation, survival, migration, and invasion of SW480 and CaCO2 CRC cells. Furthermore, mRNA and protein levels of chloride channel accessory 4 (CLCA4) were lower in CRC cells and tissues. Bioinformatics and a luciferase reporter assay confirmed that CLCA4 was a miR-19a target. Further, miR-19a inhibition increased CLCA4 expression. The inhibitory effect of miR-19a on cell growth, survival, migration, and invasion was reversed by knockdown of CLCA4 expression. The data demonstrated that the miR-19a/CLCA4 axis modulates phospho-activation of the PI3K/AKT pathway in CRC cells. In conclusion, our results revealed that miR-19a overexpression decreases CLCA4 levels to promote CRC oncogenesis, suggesting that miR-19a inhibitors have potential applications for future therapeutic of CRC.

MicroRNAs and 'Sponging' Competitive Endogenous RNAs Dysregulated in Colorectal Cancer: Potential as Noninvasive Biomarkers and Therapeutic Targets

The gastrointestinal (GI) tract in mammals is comprised of dozens of cell types with varied functions, structures, and histological locations that respond in a myriad of ways to epigenetic and genetic factors, environmental cues, diet, and microbiota. The homeostatic functioning of these cells contained within this complex organ system has been shown to be highly regulated by the effect of microRNAs (miRNA). Multiple efforts have uncovered that these miRNAs are often tightly influential in either the suppression or overexpression of inflammatory, apoptotic, and differentiation-related genes and proteins in a variety of cell types in colorectal cancer (CRC). The early detection of CRC and other GI cancers can be difficult, attributable to the invasive nature of prophylactic colonoscopies. Additionally, the levels of miRNAs associated with CRC in biofluids can be contradictory and, therefore, must be considered in the context of other inhibiting competitive endogenous RNAs (ceRNA) such as lncRNAs and circRNAs. There is now a high demand for disease treatments and noninvasive screenings such as testing for bloodborne or fecal miRNAs and their inhibitors/targets. The breadth of this review encompasses current literature on well-established CRC-related miRNAs and the possibilities for their use as biomarkers in the diagnoses of this potentially fatal GI cancer.

Long Non-Coding RNA in Gastric Cancer: Mechanisms and Clinical Implications for Drug Resistance

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide, with high recurrence and mortality rate. Chemotherapy, including 5-fluorouracil (5-FU), adriamycin (ADR), vincristine (VCR), paclitaxel (PTX), and platinum drugs, remains one of the fundamental methods of GC treatment and has efficiently improved patients’ prognosis. However, most patients eventually develop resistance to chemotherapeutic agents, leading to the failure of clinical treatment and patients’ death. Recent studies suggest that long non-coding RNAs (lncRNAs) are involved in the drug resistance of GC by modulating the expression of drug resistance-related genes via sponging microRNAs (miRNAs). Moreover, lncRNAs also play crucial roles in GC drug resistance via a variety of mechanisms, such as the regulation of the oncogenic signaling pathways, inhibition of apoptosis, induction of autophagy, modulation of cancer stem cells (CSCs), and promotion of the epithelial-to-mesenchymal transition (EMT) process. Some of lncRNAs exhibit great potential as diagnostic and prognostic biomarkers, as well as therapeutic targets for GC patients. Therefore, understanding the role of lncRNAs and their mechanisms in GC drug resistance may provide us with novel insights for developing strategies for individual diagnosis and therapy. In this review, we summarize the recent findings on the mechanisms underlying GC drug resistance regulated by lncRNAs. We also discuss the potential clinical applications of lncRNAs as biomarkers and therapeutic targets in GC.

Crosstalk between lncRNAs and miRNAs in gastrointestinal cancer drug resistance

Gastrointestinal cancers are one of the most prevalent malignancies worldwide. Dysregulation of lncRNAs by epigenetic alteration is crucial in gastrointestinal carcinogenesis. Epigenetic alteration includes DNA methylation, chromatin remodeling, histone modifications, and deregulated-gene expression by miRNAs. LncRNAs are involved in biological processes, including, uncontrolled cell division, migration, invasion, and resistance to apoptosis and drugs. Multiple-drug resistance (MDR) is a crucial obstacle in effective chemotherapy for gastrointestinal cancers. MDR can be associated with the prognosis and diagnosis of patients receiving chemotherapeutic agents (i.e. cisplatin, oxaliplatin, platinum, 5-fluorouracil, gefitinib, methotrexate, taxol, cetuximab, docetaxel, and gemcitabine). In this review, we focused on recently known lncRNAs and their relation with miRNAs and chemotherapeutic drugs, and their modulation in gastrointestinal cancers. Moreover, we mentioned the future prospective and clinical application of lncRNAs as a critical indicator and biomarker in diagnosis, prognosis, staging, grading, and treatment of gastrointestinal cancers.

Current Advances and Outlook in Gastric Cancer Chemoresistance: A Review

BACKGROUND

Surgical resection of the lesion is the standard primary treatment of gastric cancer. Unfortunately, most patients are already in the advanced stage of the disease when they are diagnosed with gastric cancer. Alternative therapies, such as radiation therapy and chemotherapy, can achieve only very limited benefits. The emergence of cancer drug resistance has always been the major obstacle to the cure of tumors. The main goal of modern cancer pharmacology is to determine the underlying mechanism of anticancer drugs.

OBJECTIVE

Here, we mainly review the latest research results related to the mechanism of chemotherapy resistance in gastric cancer, the application of natural products in overcoming the chemotherapy resistance of gastric cancer, and the new strategies currently being developed to treat tumors based on immunotherapy and gene therapy.

CONCLUSION

The emergence of cancer drug resistance is the main obstacle in achieving alleviation and final cure for gastric cancer. Mixed therapies are considered to be a possible way to overcome chemoresistance. Natural products are the main resource for discovering new drugs specific for treating chemoresistance, and further research is needed to clarify the mechanism of natural product activity in patients. .

Research updates on the clinical implication of long noncoding RNA in digestive system cancers and chemoresistance

Long noncoding RNAs (lncRNAs) are implicated in various biological processes, such as cell proliferation, differentiation, apoptosis, migration, and invasion. They are also key players in various biological pathways. LncRNA was considered as 'translational noise' before 1980s. It has been reported that lncRNAs are aberrantly expressed in different cancers, either as oncogene or tumor suppressor gene. Therefore, more and more lncRNAs are recognized as potential diagnostic biomarkers and/or therapeutic targets. As competitive endogenous RNA, lncRNAs can interact with microRNA to alter the expression of target genes, which may have extensive clinical implications in cancers, including diagnosis, treatment, prognosis, and chemoresistance. This review comprehensively summarizes the functions and clinical relevance of lncRNAs in digestive system cancers, especially as a potential tool to overcome chemoresistance.

lncRNAs as Hallmarks for Individualized Treatment of Gastric Cancer

Gastric cancer is global cancer with a high mortality rate. A growing number of studies have found the abnormal expression of lncRNA (long noncoding RNA) in many tumors, which plays a role in promoting or inhibiting cancer. Similarly, lncRNA abnormal expression plays an essential biological function in gastric cancer. This article focuses on lncRNA involvement in the development of gastric cancer in terms of cell cycle disorder, apoptosis inhibition, metabolic remodeling, promotion of tumor inflammation, immune escape, induction of angiogenesis, and epithelial mesenchymal transition (EMT). The involvement of lncRNA in the development of gastric cancer is related to drug resistance, such as cisplatin and multi-drug resistance. It can also be used as a potential marker for the diagnosis and prognosis of gastric cancer and a target for the treatment. With an in-depth understanding of the mechanism of lncRNA in gastric cancer, new ideas for personalized treatment of gastric cancer are expected.

Effects of lncRNA ANRIL-knockdown on the proliferation, apoptosis and cell cycle of gastric cancer cells

Gastric cancer is one of the most common types of malignant tumor of the gastrointestinal tract worldwide. Cisplatin (DDP) is a commonly used chemotherapeutic drug in the clinic; however, the resistance of gastric cancer cells to DDP limits its efficacy. In the present study, drug-resistant gastric cancer cell lines were constructed using the stepwise continuous selection method, and the relative expression levels of long non-coding RNA (lncRNA) CDKN2B antisense RNA 1 (ANRIL) and microRNA (miR)-181a-5p were detected using reverse transcription-quantitative PCR. The knockdown of lncRNA ANRIL and miR-181a-5p expression was performed by transfection with shRNA-ANRIL and an miR-181a-5p inhibitor, respectively. Cellular proliferation and sensitivity to DDP were assessed using Cell Counting Kit-8 analysis. Cell apoptosis and cell cycle distribution were assessed using flow cytometry and western blotting. The binding relationships between ANRIL, miR-181a-5p and cyclin G1 (CCNG1) were verified using a dual luciferase reporter assay. The results revealed that the expression levels of miR-181a-5p were downregulated in all drug-resistant cell lines. ANRIL-knockdown inhibited cellular proliferation, and promoted apoptosis and cell cycle arrest; however, following the knockdown of miR-181a-5p, the inhibition of cell cycle arrest was alleviated. Notably, miR-181a-5p, ANRIL and CCNG1 were found to have targeting relationships. In conclusion, the findings of the present study suggested that knocking down the expression of ANRIL inhibited cellular proliferation, and promoted apoptosis and cell cycle arrest. Furthermore, its downstream target, miR-181a-5p, inhibited the proliferation of drug-resistant cells and enhanced their sensitivity to DDP.

Aberrant expression of LncRNA CASC2 mediated the cell viability, apoptosis and autophagy of colon cancer cells by sponging miR-19a via NF-κB signaling pathway

Abnormal and rapid proliferation of colon cancer cells is a severe problem that can be regulated by non-coding RNAs. Thus, our study focused on effects of lncRNA CASC2 and miR-19a on colon cancer cells. Expressions of lncRNA CASC2, miR-19a, Bcl-2, Bax and NF-κB/p65 were examined by RT-qPCR. Cell viabilities were detected by CCK-8. A luciferase report assay was used for measuring binding conditions between lncRNA CASC2 and miR-19a. Western blotting was used to evaluate expression of LC3-I, LC3-II and p62 related to autophagy. Expression of lncRNA CASC2 lower in cancer cell lines and the overexpression reduced the cell viability of HT29 and SW480. Furthermore, Bcl-2 was suppressed by overexpressed lncRNA CASC2, while Bax was upregulated. LC3-Ⅰ and p62 were both inhibited, but LC3-Ⅱ was promoted. MiR-19a was predicted to bind lncRNA CASC2 and expressed higher in cancer cell lines. Overexpressed miR-19a reduced expression of lncRNA CASC2 and increased cell viability. This was repressed by upregulated lncRNA CASC2. Bcl-2 and Bax expression and proteins implicated in autophagy that are regulated by lncRNA CASC2 upregulation were reversed by miR-19a overexpression. NF-κB was upregulated in colon cancer cell lines, while inhibition of NF-κB reversed functions of lncRNA CASC2 and magnified roles of miR-19a. Our findings showed that lncRNA CASC2 inhibited cell viability in colon cancer cell lines and miR-19a reversed its functions through the NF-κB signalling pathway, suggesting that these could be factors in treating colon cancer in the future.

The effects and mechanism of α-mangostin on chemosensitivity of gastric cancer cells

This work investigated the effect of α-mangostin (α-M) on gastric cancer (GC) cell chemoresistance and its underlying mechanisms. Different concentrations of α-M and CDDP were applied to treat GC cells (SGC7901) and CDDP-resistant GC cells (SGC7901/CDDP) for 24 or 48 h. CCK-8 assays were used to measure the inhibitory effect of CDDP or α-M on SGC7901 and SGC7901/CDDP cells as well as the half-maximal inhibitory concentrations (IC50) of α-M for SGC7901 and SGC7901/CDDP cells. The optimal concentration and induction time of CDDP or α-M were determined. SGC7901/CDDP cells were treated with CDDP or/and α-M, where some of them were transfected with pcDNA3.1 or pcDNA3.1-EBI3. Cell proliferation and apoptosis were assessed as well as the levels of EBI3, STAT3, p-STAT3, autophagy-related proteins, and apoptosis-related proteins. CDDP inhibited SGC7901 cell proliferation in a dose-dependent manner. The IC50 of α-M for SGC7901 cells was 12.86 μM and that for SGC7901/CDDP cells was 13.69 μM. The optimal concentrations of CDDP and α-M for SGC7901/CDDP cells were 2 and 15 μM, respectively, and the optimal time was 48 h. The SGC7901/CDDP cells in the CDDP+/α-M+ group had elevated inhibition of proliferation and apoptosis rates. Western blot analysis revealed enhanced levels of LC3-II/I and Beclin1, reduced p62 level, decreased Bcl2 level, and increased levels of Bax and cleaved caspase-3/9. The EBI3/STAT3 pathway was implicated in the effect of α-M on SGC7901/CDDP cell development. α-M increases the chemosensitivity of GC cells by facilitating autophagy and inactivating the EBI3/STAT3 pathway.

Role of Long Non-Coding RNAs in the Chemoresistance of Gastric Cancer: A Systematic Review

PURPOSE

Accumulating evidence demonstrates that long non-coding RNAs (lncRNAs) play a vital role in the chemoresistance of gastric cancer (GC). The present systematic review summarises the emerging role, potential targets or pathways and regulatory mechanisms of lncRNAs involved in chemoresistance and proposes a number of clinical implications of lncRNAs as novel therapeutic targets for GC.

METHODS

Studies on lncRNAs involved in the chemoresistance of GC published until July 2020 in the PubMed and Web of Science databases were systematically reviewed and the expression form, role in chemoresistance, targets or pathways, corresponding drugs and potential mechanisms of relevant lncRNAs were summarised in detail.

RESULTS

A total of 48 studies were included in this systematic review. Amongst these studies, 32 involved single drug resistance and 16 involved in multidrug resistance (MDR). The 48 studies collected described 38 lncRNAs in the drug-resistant cells of GC, including 33 upregulated and 5 downregulated lncRNAs. Cisplatin (DDP) was the most studied drug and lncRNA MALAT1 was the most studied lncRNA related to the chemoresistance of GC. The potential mechanisms of chemoresistance for lncRNAs in GC mainly included, amongst others, reduction of apoptosis, induction of autophagy, repair of DNA damage, promotion of epithelial-mesenchymal transition (EMT) and regulation of the related signalling pathways.

CONCLUSION

LncRNAs play a vital role in the chemoresistance of GC and are novel therapeutic targets for the disease. Detailed chemoresistance mechanisms, translational studies and clinical trials on lncRNAs in GC are urgently needed.

Long Noncoding RNAs: New Regulators of Resistance to Systemic Therapies for Gastric Cancer

Gastric cancer (GC) is the second leading cause of cancer mortality and the fourth most commonly diagnosed malignant disease, with approximately 951,000 new cases diagnosed and approximately 723,000 cases of mortality each year. The highest mortality rate of GC is in East Asia, and the lowest is in North America. A large number of studies have demonstrated that GC patients are characterized by higher morbidity, metastasis rates, and mortality and lower early diagnosis rates, radical resection rates, and 5-year survival rates. All cases of GC can be divided into two important stages, namely, early- and advanced-stage GC, and the stage mainly determines the treatment strategy for and the therapeutic effect in GC patients. Patients with early-stage GC undergo radical surgery followed by chemotherapy, and the 5-year survival rate can be as high as 90%. However, patients with advanced-stage GC cannot undergo radical surgery because they are at risk for metastasis; therefore, they can choose only radiotherapy or chemotherapy and have a poor prognosis. Based on the lack of specific clinical manifestations and detection methods, most GC patients (>70%) are diagnosed in the advanced stage; therefore, continued efforts toward developing treatments have been focused on advanced-stage GC patients and include molecular targeted therapy, immunotherapy, and small molecular therapy. Nevertheless, in recent years, accumulating evidence has indicated that small molecules, especially long noncoding RNAs (lncRNAs), are involved in the occurrence, development, and progression of GC, and their abundantly dysregulated expression has been identified in GC tissues and cell lines. Therefore, lncRNAs are considered easily detectable molecules and ideal biomarkers or target-specific agents for the future diagnosis or treatment of GC. In this review, we primarily discuss the status of GC, the role of lncRNAs in GC, and the emerging systemic treatments for GC.

The role of long non-coding RNAs in mediating chemoresistance by modulating autophagy in cancer

Cancer is a complex process in which protein-coding and non-coding genes play essential roles. Long noncoding RNAs (lncRNAs), as a subclass of noncoding genes, are implicated in various cancer processes including growth, proliferation, metastasis, and angiogenesis. Due to presence in body fluids such as blood and urine, lncRNAs have become novel biomarkers in cancer detection, diagnosis, progression, and therapy response. Remarkably, increasing evidence has verified that lncRNAs play essential roles in chemoresistance by targeting different signalling pathways. Autophagy, a highly conserved process in response to environmental stresses such as starvation and hypoxia, plays a paradoxical role in inducing resistance or sensitivity to chemotherapy agents. In this regard, we reviewed chemoresistance, the role of lncRNAs in cancer, and the role of lncRNAs in chemoresistance by modulating autophagy.

Non-coding RNAs underlying chemoresistance in gastric cancer

BACKGROUND

Gastric cancer (GC) is a major health issue in the Western world. Current clinical imperatives for this disease include the identification of more effective biomarkers to detect GC at early stages and enhance the prevention and treatment of metastatic and chemoresistant GC. The advent of non-coding RNAs (ncRNAs), particularly microRNAs (miRNAs) and long-non coding RNAs (lncRNAs), has led to a better understanding of the mechanisms by which GC cells acquire features of therapy resistance. ncRNAs play critical roles in normal physiology, but their dysregulation has been detected in a variety of cancers, including GC. A subset of ncRNAs is GC-specific, implying their potential application as biomarkers and/or therapeutic targets. Hence, evaluating the specific functions of ncRNAs will help to expand novel treatment options for GC.

CONCLUSIONS

In this review, we summarize some of the well-known ncRNAs that play a role in the development and progression of GC. We also review the application of such ncRNAs in clinical diagnostics and trials as potential biomarkers. Obviously, a deeper understanding of the biology and function of ncRNAs underlying chemoresistance can broaden horizons toward the development of personalized therapy against GC.

lncRNA CASC2 Enhances 131I Sensitivity in Papillary Thyroid Cancer by Sponging miR-155

Long noncoding RNA cancer susceptibility candidate 2 (CASC2) has been reported to play an anticancer role in papillary thyroid cancer (PTC). Radioiodine (¹³¹I) is a common option for the treatment of PTC. However, the role and mechanism of CASC2 in ¹³¹I sensitivity remain unclear. In this study, ¹³¹I-resistant cells were constructed through continuous treatment of ¹³¹I. The expression levels of CASC2 and miR-155 were measured by qRT-PCR. The IC50 of ¹³¹I was analyzed by cell viability using MTT assay. Flow cytometry was conducted to determine cell apoptosis induced by ¹³¹I. The association between CASC2 and miR-155 was evaluated by luciferase assay and RNA immunoprecipitation. A mouse xenograft model was built to explore the effect of CASC2 on the growth of ¹³¹I-resistant PTC cells in vivo. Results showed that CASC2 expression was decreased in PTC tissues and cells, and low expression of CASC2 was associated with poor outcome of patients. CASC2 level was reduced in ¹³¹I-resistant cells. Knockdown of CASC2 inhibited ¹³¹I sensitivity in thyroid cancer cells. Overexpression of CASC2 enhanced ¹³¹I sensitivity in constructed resistant PTC cells. CASC2 was a decoy of miR-155, and CASC2-mediated promotion of ¹³¹I sensitivity was weakened by decreasing miR-155. Abundance of CASC2 inhibited the growth of ¹³¹I-resistant cells in vivo. As a conclusion, CASC2 increases ¹³¹I sensitivity in PTC by sponging miR-155, providing a novel target for the treatment of thyroid cancer patients with ¹³¹I resistance.

Aloperine Exerts Antitumor Effects on Bladder Cancer in vitro

Background

Human bladder cancer is the most common malignant tumor of the urinary system and one of the 10 most common tumors of the whole body. Although most patients with bladder cancer exhibit a good prognosis with standard treatment, effective therapies for patients with a recurrent or advanced bladder cancer are unavailable. Therefore, highly effective drugs to treat such patients need to be developed. Aloperine (ALO), a natural compound isolated from Sophora alopecuroides, has antitumor properties. However, the role of ALO in human bladder cancer remains unclear.

Methods

In the present study, MTT was used to detect the cytotoxic effect of ALO on human BC cell line EJ and human urothelium cell line SV-HUC-1cells. Meanwhile, in order to investigate the effects of ALO on the proliferation, apoptosis, migration, and invasion of BC EJ cells and its mechanism by Cell Counting Kit-8 (CCK-8) assay, immunofluorescence, Hoechst 33342 staining, wound scratch assay, transwell migration and invasion assay, Western blot analysis.

Results

ALO can inhibit the proliferation and invasion of human bladder cancer EJ cells, and is low-toxic to human urothelium cells. Moreover, it can promote cellular apoptosis in vitro. Further analysis demonstrated the involvement of Caspase-dependent apoptosis following ALO treatment. ALO also downregulated the protein expression levels of Ras, p-Raf1 and p-Erk1/2.

Conclusion

ALO is a potential drug for human bladder cancer therapy.

lncRNA CASC2 inhibits lipopolysaccharide‑induced acute lung injury via miR‑27b/TAB2 axis

Long non-coding RNA (lncRNA) cancer susceptibility candidate 2 (CASC2) has been reported to exert an important role in acute lung injury (ALI). The present study aimed to investigate the potential underlying mechanism of CASC2 in ALI progression. Reverse transcription-quantitative PCR was conducted to examine the expression of CASC2, microRNA (miR/miRNA)-27b and TGF-β activated kinase 1 and MAP3K7-binding protein 2 (TAB2) in A549 cells. Cell viability and apoptosis were analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry. Enzyme-linked immunosorbent assay was used to measure the levels of inflammatory-related cytokines to assess the inflammatory response, including interleukin-1β (IL-1β), IL-6 and tumor necrosis factor α (TNF-α). The binding sites of miR-27b in CASC2 or TAB2 were predicted using LncBase or microT-CDS software, following which dual-luciferase reporter and RNA binding protein immunoprecipitation assays were performed to confirm the target relationship between miR-27b and CASC2 or TAB2. The protein expression of TAB2 was detected by western blotting. The decreased viability, and increased apoptosis and inflammatory responses were attenuated by the accumulation of CASC2 in lipopolysaccharide (LPS)-stimulated A549 cells. CASC2 could directly bind to miR-27b in A549 cells. CASC2 protected A549 cells from LPS-triggered injury by downregulating miR-27b. TAB2 was a target of miR-27b in A549 cells. The influence of miR-27b depletion was reversed by the silencing of TAB2 in an ALI cell model. CASC2 could increase the expression of TAB2 by serving as a competing endogenous RNA of miR-27b in A549 cells. Collectively, the results suggested that CASC2 attenuated LPS-induced injury in the ALI cell model by modulating the miR-27b/TAB2 axis.

miR-19 Is a Potential Clinical Biomarker for Gastrointestinal Malignancy: A Systematic Review and Meta-analysis

Objectives

To assess the expression and clinical value of miR-19 in gastrointestinal malignancy. Setting. Embase, Web of Science, PubMed, and other databases were retrieved to screen out relevant studies until December 31, 2019. Participants. Gastrointestinal cancer patients with the description of miR-19 expression, as well as the correlation between miR-19 and clinicopathological characteristics or prognosis. Main Outcome Measures. Pooled odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI) was obtained to determine miR-19 expression in gastrointestinal malignancy and the association between miR-19 and patients' clinical characteristics and survival.

Results

Thirty-seven studies were included in this study. miR-19 levels in gastrointestinal malignancy, especially in hepatocellular (OR = 4.88, 95%  CI = 2.38‐9.99), colorectal (OR = 4.81, 95%  CI = 2.38‐9.72), and pancreatic (OR = 5.12, 95%  CI = 2.43‐10.78) cancers, were significantly overexpressed, and miR-19 was tightly related to some clinicopathological characteristics, such as lymph node metastasis (OR = 1.74, 95%  CI = 1.05‐2.86). Although gastrointestinal cancer patients with low and high miR-19 expression had comparable OS (overall survival) and DFS (disease-free survival), subgroup analyses showed that patients with high miR-19 presented better DFS than those with low miR-19 in liver cancer (HR = 0.46, 95%  CI = 0.30‐0.71).

Conclusions

miR-19 might be a potential progression and prognostic biomarker for gastrointestinal malignancy.

lncRNA and Mechanisms of Drug Resistance in Cancers of the Genitourinary System

Available systemic treatment options for cancers of the genitourinary system have experienced great progress in the last decade. However, a large proportion of patients eventually develop resistance to treatment, resulting in disease progression and shorter overall survival. Biomarkers indicating the increasing resistance to cancer therapies are yet to enter clinical routine. Long non-coding RNAs (lncRNA) are non-protein coding RNA transcripts longer than 200 nucleotides that exert multiple types of regulatory functions of all known cellular processes. Increasing evidence supports the role of lncRNAs in cancer development and progression. Additionally, their involvement in the development of drug resistance across various cancer entities, including genitourinary malignancies, are starting to be discovered. Consequently, lncRNAs have been suggested as factors in novel therapeutic strategies to overcome drug resistance in cancer. In this review, the existing evidences on lncRNAs and their involvement in mechanisms of drug resistance in cancers of the genitourinary system, including renal cell carcinoma, bladder cancer, prostate cancer, and testicular cancer, will be highlighted and discussed to facilitate and encourage further research in this field. We summarize a significant number of lncRNAs with proposed pathways in drug resistance and available reported studies.

Ginsenoside Rg3 suppresses the growth of gemcitabine-resistant pancreatic cancer cells by upregulating lncRNA-CASC2 and activating PTEN signaling

Pancreatic cancer is one of the most fatal malignancies with high mortality. Gemcitabine (GEM)-based chemotherapy is the most important treatment. However, the development of GEM resistance leads to chemotherapy failure. Previous studies demonstrated the anticancer activity of ginsenoside Rg3 in a variety of carcinomas through modulating multiple signaling pathways. In the present study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, colony formation assay, flow cytometry apoptosis assay, Western blotting assay, xenograft experiment, and immunohistochemistry assay were performed in GEM-resistant pancreatic cancer cell lines. Ginsenoside Rg3 inhibited the viability of GEM-resistant pancreatic cancer cells in a time-dependent and concentration-dependent manner through induction of apoptosis. The level of long noncoding RNA cancer susceptibility candidate 2 (CASC2) and PTEN expression was upregulated by the ginsenoside Rg3 treatment, and CASC2/PTEN signaling was involved in the ginsenoside Rg3-induced cell growth suppression and apoptosis in GEM-resistant pancreatic cancer cells. Ginsenoside Rg3 could be an effective anticancer agent for chemoresistant pancreatic cancer.

Long non-coding RNAs towards precision medicine in gastric cancer: early diagnosis, treatment, and drug resistance

Gastric cancer is a deadly disease and remains the third leading cause of cancer-related death worldwide. The 5-year overall survival rate of patients with early-stage localized gastric cancer is more than 60%, whereas that of patients with distant metastasis is less than 5%. Surgical resection is the best option for early-stage gastric cancer, while chemotherapy is mainly used in the middle and advanced stages of this disease, despite the frequently reported treatment failure due to chemotherapy resistance. Therefore, there is an unmet medical need for identifying new biomarkers for the early diagnosis and proper management of patients, to achieve the best response to treatment. Long non-coding RNAs (lncRNAs) in body fluids have attracted widespread attention as biomarkers for early screening, diagnosis, treatment, prognosis, and responses to drugs due to the high specificity and sensitivity. In the present review, we focus on the clinical potential of lncRNAs as biomarkers in liquid biopsies in the diagnosis and prognosis of gastric cancer. We also comprehensively discuss the roles of lncRNAs and their molecular mechanisms in gastric cancer chemoresistance as well as their potential as therapeutic targets for gastric cancer precision medicine.

The role of long non-coding RNA CASC2 in the carcinogenesis process

The lncRNA cancer susceptibility candidate 2 (CASC2) has been initially discovered in a genomic area on 10q26 that is commonly lost in human endometrial cancer. Subsequent assessments revealed its down-regulation in almost all kinds of cancer including glioma, breast cancer, colorectal cancer, lung cancer, ovarian cancer and hepatocellular carcinoma. Yet, it has been shown to be up-regulated in astrocytoma and in paclitaxel (PTX) resistant breast cancer tissues. In vitro studies have shown the role of this lncRNA in suppression of cell proliferation and induction of apoptosis. Animal studies have shown that over-expression of CASC2 suppresses tumorigenesis of human cancer cells in xenograft models. Diagnostic power of CASC2 levels has been evaluated in a number of human cancers and the best parameters have been demonstrated in pituitary adenomas and oral squamous cell carcinoma. Taken together, the main body of evidence show a tumor suppressor role of CASC2 and indicate up-regulation of this lncRNA as a putative therapeutic modality for human cancers. In this review, we summarize the data regarding expression pattern, function and diagnostic role of CASC2 in human cancer based on the results of cell line studies, animal investigations and human studies.

Inhibition of miR-19a partially reversed the resistance of colorectal cancer to oxaliplatin via PTEN/PI3K/AKT pathway

Oxaliplatin is a platinum-based chemotherapeutic drug that is effective and commonly used in the treatment of colorectal cancer (CRC). However, long-term use of oxaliplatin usually induces significant drug resistance. It is urgent to develop strategies to reverse the oxaliplatin resistance to CRC cells. In the present study, we established the model of oxaliplatin-resistant CRC cell lines (SW480/R and HT29/R) through continuous treatment of SW480 and HT29 cells with oxaliplatin. Results of qRT-PCR analysis showed that expression of miR-19a was significantly increased in SW480/R and HT29/R compared to their parental SW480 and HT29. However, combination treatment with anti-miR-19a, an antisense oligonucleotide of miR-19a, was found to resensitize SW480/R and HT29/R cells to oxaliplatin treatment. In the mechanism research, we found that anti-miR-19a increased the expression of PTEN and thus inhibited the phosphorylation of PI3K and AKT in SW480/R and HT29/R cells. As a result, mitochondrial apoptosis induced by oxaliplatin was expanded. We demonstrated that PTEN was the target of miR-19a and inhibition of miR-19a partially reversed the resistance of colorectal cancer to oxaliplatin via PTEN/PI3K/AKT pathway.

Noncoding RNAs in gastric cancer: implications for drug resistance

Gastric cancer is the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Advanced gastric cancer patients can notably benefit from chemotherapy including adriamycin, platinum drugs, 5-fluorouracil, vincristine, and paclitaxel as well as targeted therapy drugs. Nevertheless, primary drug resistance or acquisition drug resistance eventually lead to treatment failure and poor outcomes of the gastric cancer patients. The detailed mechanisms involved in gastric cancer drug resistance have been revealed. Interestingly, different noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), are critically involved in gastric cancer development. Multiple lines of evidences demonstrated that ncRNAs play a vital role in gastric cancer resistance to chemotherapy reagents and targeted therapy drugs. In this review, we systematically summarized the emerging role and detailed molecular mechanisms of ncRNAs impact drug resistance of gastric cancer. Additionally, we propose the potential clinical implications of ncRNAs as novel therapeutic targets and prognostic biomarkers for gastric cancer.

Research Progress in microRNA-Based Therapy for Gastric Cancer

Gastric cancer (GC) is one of the leading causes of tumor-related mortality. In addition to surgery and endoscopic resection, systemic therapy remains the main treatment option for GC, especially for advanced-stage disease and for cases not suitable for surgical therapy. Hence, improving the efficacy of systemic therapy is still an urgent problem to overcome. In the past decade, the essential roles of microRNAs (miRNAs) in tumor treatment have been increasingly recognized. In particular, miRNAs were recently shown to reverse the resistance to chemotherapy drugs such as 5-fluorouracil, cisplatin, and doxorubicin. Synthesized nanoparticles loaded with mimics or inhibitors of miRNAs can directly target tumor cells to suppress their growth. Moreover, exosomes may serve as promising safe carriers for mimics or inhibitors of miRNAs to treat GC. Some miRNAs have also been shown to play roles in the mechanism of action of other anti-tumor drugs. Therefore, in this review, we highlight the research progress on microRNA-based therapy in GC and discuss the challenges and prospects associated with this strategy. We believe that microRNA-based therapy has the potential to offer a clinical benefit to GC patients, and this review would contribute to and motivate further research to promote this field toward this ultimate goal.

The regulatory roles and potential prognosis implications of long non-coding RNAs in gastric cancer

Accumulating dysregulated lncRNAs have been demonstrated to execute vital functions in the pathogenesis and progress of gastric cancer (GC) through versatile molecular mechanisms. In this review, we classify the mechanisms of dysregulated lncRNAs in GC into several governing types according to their roles at molecular level. For each regulatory role, we illustrate several instructive examples and introduce significant effects of lncRNAs on cellular biological properties of GC. Besides, we summarize a group of lncRNA-signatures that are potential biomarkers in the prediction of prognosis for GC patients.

Long noncoding RNA CASC2 suppresses esophageal squamous cell carcinoma progression by increasing SOCS1 expression

Objective

Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer-related deaths worldwide. Emerging evidence suggests the involvement of long noncoding RNAs (lncRNAs) in tumorigenesis. LncRNA Cancer Susceptibility Candidate 2 (CASC2) has been demonstrated to act as a tumor suppressor contributing to the development and progression of several cancers. However, the functional significance and underlying mechanism of CASC2 in ESCC progression has not been well elucidated.

Methods

The expression levels of CASC2 in ESCC tissues were detected by qRT-PCR. CASC2 overexpression and knockdown models were established and used to investigate the functional role of CASC2 in ESCC cells. RIP, RNA pull-down and dual-luciferase assay was used to detect the association between CASC2 and miR-155. The interaction between CASC2 and Suppressor Of Cytokine Signaling 1 (SOCS1) was assessed by RIP and RNA pull-down assays.

Results

In the present study, we found that CASC2 was significantly downregulated in ESCC tissues and positively correlated with overall survival time of patients with ESCC. Functional assays demonstrated that CASC2 suppressed proliferation, migration and invasion, as well as enhanced drug sensitivity in ESCC cells. Mechanistically, CASC2 inhibited ESCC progression by upregulating the expression of SOCS1 via two different ways. CASC2 acted as competing endogenous RNA (ceRNA) for miR-155 to post-transcriptionally increase SOCS1 expression. On the other hand, CASC2 was capable of interacting with SOCS1 protein and suppressing its degradation.

Conclusion

Conclusively, these results demonstrated that CASC2 could exert as a tumor suppressive lncRNA in ESCC progression via regulating SOCS1.

MiR-19a modulates hypoxia-mediated cell proliferation and migration via repressing PTEN in human pulmonary arterial smooth muscle

AIM

The dysfunction of human pulmonary arterial smooth muscle cells (HPASMCs) has been suggested to participate in the pathophysiology of pulmonary arterial hypertension (PAH). This study determined miR-19a expression in hypoxia-induced HPASMCs and explored the mechanistic actions of miR-19a in hypoxia-induced HPASMC proliferation and migration.

METHODS

QRT-PCR and western blot assays respectively determined the mRNA and protein expression of miR-19a, phosphatase and tensin homolog (PTEN) and hypoxia-inducible factor-1 alpha (HIF-1α). In vitro functional assays determined HPASMC proliferation and migration, respectively. Luciferase reporter assay determined interaction between miR-19a and PTEN. The knockdown effects of miR-19a on PAH were confirmed in in vivo mice model.

RESULTS

Hypoxia treatment time-dependently up-regulated miR-19a expression and enhanced cell proliferation in HPASMCs. MiR-19a overexpression increased cell proliferation and migration of HPASMCs, while repression of miR-19a reduced cell proliferative and migratory potentials of hypoxia-treated HPASMCs. Bioinformatics analysis and luciferase reporter assay showed that PTEN 3' untranslated region was targeted by miR-19a, and miR-19a repressed the mRNA and protein expression of PTEN in HPASMCs. Further rescue studies revealed that miR-19a regulated proliferative and migratory potentials of hypoxia-treated HPASMCs via suppressing PTEN expression. In addition, HIF-1α was identified as one of the mediators for the hypoxia-induced aberrant expression levels of miR-19a and PTEN. MiR-19a overexpression enhanced PI3K/AKT signaling, which was attenuated by enforced expression of PTEN in HPASMCs. More importantly, knockdown of miR-19 attenuated the chronic hypoxia-induced PAH in in vivo mice model.

CONCLUSION

This study presented a novel mechanistic action of miR-19a-mediated cell proliferation and migration of HPASMCs.

Overexpression of CASC2 Improves Cisplatin Sensitivity in Hepatocellular Carcinoma Through Sponging miR-222

The long noncoding RNA cancer susceptibility candidate 2 (CASC2) has been shown to play a crucial role in cancer cell chemoresistance. However, its function and underlying molecular mechanism in hepatocellular carcinoma (HCC) chemoresistance remain unknown. In this study, we used cisplatin (DDP)-resistant HCC cells to investigate CASC2 function and its underlying mechanism. The results demonstrated that CASC2 expression was significantly reduced in HCC tissues and cells, especially in DDP-resistant HCC tissues and cells. Lower CASC2 expression was strongly correlated with shorter survival times in patients with HCC. Functionally, CASC2 overexpression sensitized DDP-resistant Huh7/DDP and SMMC-7721/DDP cells to DDP. Mechanically, CASC2 improved the sensitivity of HCC cells to DDP through sponging miR-222. Taken together, these findings suggested that overexpression of CASC2 overcame DDP resistance in HCC by regulating miR-222 expression, thereby providing a potential therapeutic strategy for overcoming HCC cell chemoresistance.

E2F6-mediated lncRNA CASC2 down-regulation predicts poor prognosis and promotes progression in gastric carcinoma

AIMS

To investigate the potential biological role of E2F6 and its underlying molecular mechanism in gastric carcinoma (GC) progression.

MAIN METHODS

The expressions of cancer susceptibility candidate 2 (CASC2), E2F6 and matrix metalloprotein-2 (MMP-2) were measured by quantitative real-time polymerase chain reaction and western blotting. The inhibitory effect of E2F6 on CASC2 was evaluated using luciferase reporter assay. Cell growth was assessed by colony formation assay and cell counting kit-8. Cell invasion and apoptosis were measured by transwell assay and flow cytometry assay, respectively. In vivo tumorigenicity was assessed by tumor xenografts in nude mice.

KEY FINDINGS

Our data revealed that CASC2 was downregulated while E2F6 was upregulated in GC tissues and cell lines. Remarkably, lower expression of CASC2 was associated with poor survival in GC patients. E2F6 inhibited the expression of CASC2. Subsequently, reliable data showed that downregulation of E2F6 suppressed the proliferation and invasion, and promoted the apoptosis of GC cells. Furthermore, downregulation of E2F6 decreased the expression of MMP-2 and increased the activity of caspase-3. However, these changes triggered by E2F6 knockdown could be reversed by inhibition of CASC2. Moreover, we also proved that downregulation of CASC2 reverses the effect of E2F6 knockdown on tumor growth in vivo.

SIGNIFICANCE

Our data demonstrated that E2F6 could regulate the proliferation, invasion and apoptosis of GC cells via inhibiting the expression of CASC2, suggesting that E2F6/CASC2 axis is another regulator of GC progression.

In silico identification of novel lncRNAs with a potential role in diagnosis of gastric cancer

Gastric cancer (GC) is the second leading cause of cancer-related deaths in the world. Due to the shortage of adequate symptoms in the early stages, it is diagnosed when the tumor has spread to distant organs. Early recognition of GC enhances the chance of successful treatment. Molecular mechanisms of GC are still poorly understood. LncRNAs are emerging as new players in cancer in both oncogene and tumor suppressor roles. High-throughput technologies such as RNA-Seq, have revealed thousands of lncRNAs which are dysregulated in GC. In this study, we retrieved lncRNAs obtained by High-throughput technologies from OncoLnc database. Consequently, retrieved lncRNAs were compared in literature-based databases including PubMed. As a result, two lists, including experimentally validated lncRNAs and predicted lncRNAs were provided. We found 43 predicted lncRNAs that had not been experimentally validated in GC, so far. Further Bioinformatics analyses were performed to obtain the expression profile of predicted lncRNAs in tumor and normal tissues. Also, the roles and targets of predicted lncRNAs in GC were identified by related databases. Finally, using the GEPIA database was reviewed the significant relationship of predicted lncRNAs with the survival of GC patients. By recognizing the lncRNAs involved in initiation and progression of GC, they may be considered as potential biomarkers in the GC early diagnosis or targeted treatment and lead to novel therapeutic strategies. Communicated by Ramaswamy H. Sarma.

Inhibition of miR-19a protects neurons against ischemic stroke through modulating glucose metabolism and neuronal apoptosis

Background

Accumulating evidence has shown that altered microRNA (miR) modulation is implicated in the pathologies of ischemic stroke. However, it is unclear whether and how hsa-miR-19a-3p mediates cerebral ischemic injury. Herein, we investigated the functional role of miR-19a-3p in cerebral ischemic injury and explored its underlying regulatory mechanism.

Methods

In vivo ischemic/reperfusion (I/R) neuronal injury and in vitro oxygen-glucose deprivation (OGD) were established. Expression of miR-19a-3p was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Glucose uptake, lactate production, and apoptosis were determined. ADIPOR2 was predicted as a target of miR-19a-3p in silico and experimentally validated by qRT-PCR, Western blot analysis and luciferase assay assays.

Results

MiR-19a expression was significantly downregulated and upregulated in rat neurons and astrocytes, respectively (P < 0.01). A significantly elevated level of miR-19a-3p was found in I/R and OGD models in comparison to sham/control groups (P < 0.01). Expression of the glycolysis enzyme markers LDHA, PKM2, HK2, Glut1 and PDK1, apoptosis-related factors levels, apoptosis, glucose uptake, and lactate production were significantly repressed by both I/R and OGD (P < 0.01 in each case). Moreover, miR-19a-3p mimic aggravated, while miR-19a-3p inhibitor alleviated, the above observations. Adipor2 was predicted and confirmed to be a direct target of miR-19a. Furthermore, restoration of Adipor2 reversed miR-19a-3p-induced effects.

Conclusions

Collectively, our results indicate that elevated miR-19a-3p mediates cerebral ischemic injury by targeting ADIPOR2. MiR-19a-3p attenuation thus might offer hope of a novel therapeutic target for ischemic stroke injury treatment.

Induction/reversal of drug resistance in gastric cancer by non-coding RNAs (Review)

Gastric cancer (GC) is one of the most prevalent and malignant types of cancer worldwide. In China, it is the second most common type of cancer and the malignancy with the highest incidence and mortality rate. Chemotherapy for GC is not always effective due to the development of drug resistance. Drug resistance, which is frequently observed in GC, undermines the success rate of chemotherapy and the survival of patients with GC. The dysregulation of non‑coding RNAs (ncRNAs), primarily microRNAs (miRNAs or miRs) and long non‑coding RNAs (lncRNAs), is involved in the development of GC drug resistance via numerous mechanisms. These mechanisms contribute to the involvement of a large and complex network of ncRNAs in drug resistance. In this review, we focus on and summarize the latest research on the specific mechanisms of action of miRNAs and lncRNAs that modulate drug resistance in GC. In addition, we discuss future prospects and clinical applications of ncRNAs as potential targeted therapies against the chemoresistance of GC.