The HIF-2α-MALAT1-miR-216b axis regulates multi-drug resistance of hepatocellular carcinoma cells via modulating autophagy

Mechanisms of drug resistance in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most prevalent form of primary liver cancer, associated with high morbidity and mortality worldwide. Despite advancements in diagnostic methods and systemic treatments, including tyrosine kinase inhibitors (TKIs) and immune checkpoint inhibitors (ICIs), the development of drug resistance remains a significant challenge in HCC management. Traditional treatments such as surgical resection and transarterial chemoembolization offer limited efficacy, especially in advanced stages. Although novel therapies like lenvatinib, sorafenib, regorafenib, and ICIs have shown promise, their effectiveness is often hindered by primary and acquired resistance, leading to poor long-term survival outcomes. This review focuses on the molecular mechanisms underlying resistance to targeted therapies and immunotherapies in HCC. Key factors contributing to resistance include alterations in the tumor microenvironment (TME), immune evasion, hypoxia, changes in cellular metabolism, and genetic mutations. Additionally, molecular players such as ferroptosis, autophagy, apoptosis, endoplasmic reticulum stress, ABC transporters, and non-coding RNAs(ncRNAs) are discussed as contributors to drug resistance. Understanding these mechanisms is critical for the development of novel therapeutic strategies aimed at overcoming resistance, improving patient outcomes, and ultimately enhancing survival rates in HCC patients.

Autophagy mediated immune response regulation and drug resistance in cancer

Autophagy is a critical regulator of cellular homeostasis. The proteins involved in autophagy orchestrate the functions to strike the balance between cell survival and cell death in context-specific situations like aging, infections, inflammation and most importantly carcinogenesis. One of the major dead-locks in cancer treatment is the development of resistance to the available drugs (multi-drug resistance) as well as immune-suppressions in patients. Different studies over time have shown that autophagy is being involved in chemotherapy by working hand in hand with apoptosis or drug resistance through proliferative signals. Resistance to various drugs, such as, Cisplatin, Vincristine, Tamoxifen (TAM) occurs by epigenetic modifications, changed expression levels of microRNAs (miRNAs/miRs), and long non-coding RNAs (lncRNAs), which are regulated by the aberrant autophagy levels in lung, and breast cancers. More interestingly in the tumour microenvironment the immune suppressor cells also bring in autophagy in different pathway regulations either helping or opposing the whole carcinogenesis process. Macrophages, T cells, B cells, dendritic cells (DCs), neutrophils, and fibroblasts show involvement of autophagy in their differentiation and development in the tumor microenvironment (TME). Here, this extensive review for the first time tries to bring under a single canopy, several recent examples of autophagy-mediated immune regulations and autophagy-mediated epigenetically regulated drug resistance in different types of cancers.

Targeting Hypoxia and Autophagy Inhibition via Delivering Sonodynamic Nanoparticles With HIF-2α Inhibitor for Enhancing Immunotherapy in Renal Cell Carcinoma

Immune checkpoint blockers (ICBs) therapy stands as the first-line treatment option for advanced renal cell carcinoma (RCC). However, its effectiveness is hindered by the immunosuppressive tumor microenvironment (TME). Sonodynamic therapy (SDT) generates tumor cell fragments that can prime the host's antitumor immunity. Nevertheless, the hypoxic microenvironment and upregulated autophagy following SDT often lead to cancer cell resistance. In response to these challenges, a hypoxia-responsive polymer (Poly(4,4'-azobisbenzenemethanol-PMDA)-mPEG5k, P-APm) encapsulating both a HIF-2α inhibitor (belzutifan) and the ultrasonic sensitize (Chlorin e6, Ce6) is designed, to create the nanoparticle APm/Ce6/HIF. APm/Ce6/HIF combined with ultrasound (US) significantly suppresses tumor growth and activates antitumor immunity in vivo. Moreover, this treatment effectively transforms the immunosuppressive microenvironment from "immune-cold" to "immune-hot", thereby enhancing the response to ICBs therapy. The findings indicate that APm/Ce6/HIF offers a synergistic approach combining targeted therapy with immunotherapy, providing new possibilities for treating RCC.

Roles of clinical application of lenvatinib and its resistance mechanism in advanced hepatocellular carcinoma (Review)

Lenvatinib (LEN) is a multi-target TKI, which plays a pivotal role in the treatment of advanced hepatocellular carcinoma (HCC). The inevitable occurrence of drug resistance still prevents curative potential and is deleterious for the prognosis, and a growing body of studies is accumulating, which have devoted themselves to unveiling its underlying resistance mechanism and made some progress. The dysregulation of crucial signaling pathways, non-coding RNA and RNA modifications were proven to be associated with LEN resistance. A range of drugs were found to influence LEN therapeutic efficacy. In addition, the superiority of LEN combination therapy has been shown to potentially overcome the limitations of LEN monotherapy in a series of research, and a range of promising indicators for predicting treatment response and prognosis have been discovered in recent years. In this review, we summarize the latest developments in LEN resistance, the efficacy and safety of LEN combination therapy as well as associated indicators, which may provide new insight into its resistance as well as ideas in the treatment of advanced HCC.

MicroRNAs in Hepatocellular Carcinoma Pathogenesis: Insights into Mechanisms and Therapeutic Opportunities

Hepatocellular carcinoma (HCC) presents a significant global health burden, with alarming statistics revealing its rising incidence and high mortality rates. Despite advances in medical care, HCC treatment remains challenging due to late-stage diagnosis, limited effective therapeutic options, tumor heterogeneity, and drug resistance. MicroRNAs (miRNAs) have attracted substantial attention as key regulators of HCC pathogenesis. These small non-coding RNA molecules play pivotal roles in modulating gene expression, implicated in various cellular processes relevant to cancer development. Understanding the intricate network of miRNA-mediated molecular pathways in HCC is essential for unraveling the complex mechanisms underlying hepatocarcinogenesis and developing novel therapeutic approaches. This manuscript aims to provide a comprehensive review of recent experimental and clinical discoveries regarding the complex role of miRNAs in influencing the key hallmarks of HCC, as well as their promising clinical utility as potential therapeutic targets.

Competing endogenous RNAs regulatory crosstalk networks: The messages from the RNA world to signaling pathways directing cancer stem cell development

Cancer stem cells (CSCs) are one of the cell types that account for cancer heterogeneity. The cancer cells arrest in G0 and generate non-CSC progeny through self-renewal and pluripotency, resulting in tumor recurrence, metastasis, and resistance to chemotherapy. They can stimulate tumor relapse and re-grow a metastatic tumor. So, CSCs is a promising target for eradicating tumors, and developing an anti-CSCs therapy has been considered. In recent years competing endogenous RNA (ceRNA) has emerged as a significant class of post-transcriptional regulators that affect gene expression via competition for microRNA (miRNA) binding. Furthermore, aberrant ceRNA expression is associated with tumor progression. Recent findings show that ceRNA network can cause tumor progression through the effect on CSCs. To overcome therapeutic resistance due to CSCs, we need to improve our current understanding of the mechanisms by which ceRNAs are implicated in CSC-related relapse. Thus, this review was designed to discuss the role of ceRNAs in CSCs' function. Targeting ceRNAs may open the path for new cancer therapeutic targets and can be used in clinical research.

Diagnostic and prognostic role of LINC01767 in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is a primary contributor to cancer-related mortality on a global scale. However, the underlying molecular mechanisms are still poorly understood. Long noncoding RNAs are emerging markers for HCC diagnosis, prognosis, and therapeutic target. No study of LINC01767 in HCC was published.

AIM

To conduct a multi-omics analysis to explore the roles of LINC01767 in HCC for the first time.

METHODS

DESeq2 Package was used to analyze different gene expressions. Receiver operating characteristic curves assessed the diagnostic performance. Kaplan-Meier univariate and Cox multivariate analyses were used to perform survival analysis. The least absolute shrinkage and selection operator (LASSO)-Cox was used to identify the prediction model. Subsequent to the validation of LINC01767 expression in HCC fresh frozen tissues through quantitative real time polymerase chain reaction, next generation sequencing was performed following LINC01767 over expression (GSE243371), and Gene Ontology/Kyoto Encyclopedia of Genes and Genomes/Gene Set Enrichment Analysis/ingenuity pathway analysis was carried out. In vitro experiment in Huh7 cell was carried out.

RESULTS

LINC01767 was down-regulated in HCC with a log fold change = 1.575 and was positively correlated with the cancer stemness. LINC01767 was a good diagnostic marker with area under the curve (AUC) [0.801, 95% confidence interval (CI): 0.751-0.852, P = 0.0106] and an independent predictor for overall survival (OS) with hazard ratio = 1.899 (95%CI: 1.01-3.58, P = 0.048). LINC01767 nomogram model showed a satisfied performance. The top-ranked regulatory network analysis of LINC01767 showed the regulation of genes participating various pathways. LASSO regression identified the 9-genes model showing a more satisfied performance than 5-genes model to predict the OS with AUC > 0.75. LINC01767 was down-expressed obviously in tumor than para-tumor tissues in our cohort as well as in cancer cell line; the over expression of LINC01767 inhibit cell proliferation and clone formation of Huh7 in vitro.

CONCLUSION

LINC01767 was an important tumor suppressor gene in HCC with good diagnostic and prognostic performance.

Deciphering the Role of Exosomal Non-Coding RNA (ncRNA) in Drug Resistance of Gastrointestinal Tumors; an Updated Review

One of the most prevalent types of cancer worldwide today is gastric intestinal (GI) tumors. To guarantee their lives, people with a developed GI require palliative care. This covers the application of targeted medicines in addition to chemotherapy treatments including cisplatin, 5-fluorouracil, oxaliplatin, paclitaxel, and pemetrexed. Because of the evidence of drug resistance emerging in poor patient outcomes and prognoses, determining the exact process of medication resistance is motivated. Besides, it is noteworthy that exosomes and noncoding RNAs, like microRNAs and long non-coding RNAs (lncRNAs), produced from tumor cells are implicated in both GI medication resistance and the carcinogenesis and development of GI disease. Biochemical events related to the cell cycle, differentiation of cells, growth, and pluripotency, in addition to gene transcription, splicing, and epigenetics, are all regulated by noncoding RNAs (ncRNAs). Therefore, it should come as a wonder that several ncRNAs have been connected in recent years to drug susceptibility and resistance as well as tumorigenesis. Additionally, through communicating directly with medications, altering the transcriptome of tumor cells, and affecting the immune system, exosomes may govern treatment resistance. Because of this, exosomal lncRNAs often act as a competitive endogenous RNA (ceRNA) of miRNAs to carry out its role in modifying drug resistance. In light of this, we provide an overview of the roles and processes of ncRNA-enriched exosomes in GI medication resistance.

Predictive value of peripheral blood leukocytes-based methylation of Long non-coding RNA MALAT1 and H19 in the chemotherapy effect and prognosis of gastric cancer

BACKGROUND

The predictive value of the methylation of Long non-coding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) and H19 promoters in peripheral blood leukocytes as a non-invasive biomarker for the chemotherapy effect and prognosis gastric cancer (GC) is unclear.

METHODS

The DNA methylation of H19 and MALAT1 between chemotherapy-sensitive and non-sensitive groups and between groups with better and worse survival of GC was compared using regression analyses. Several predictive nomograms were constructed. The genetic alteration of MALAT1 and H19 and the association between gene expression and immune status in GC were also investigated using bioinformatics analysis.

RESULTS

Higher genetic methylations in peripheral blood were noticed in GC groups with poorer survival. The constructed nomograms presented strong predictive values for the chemotherapy effect and 3-year survival of disease-free survival, progression-free survival, and overall survival, with the area under the curve as 0.838, 0.838, 0.912, and 0.925, respectively. Significant correlations between MALAT1 or H19 expression and marker genes of immune checkpoints and immune pathways were noticed. The high infiltration of macrophages in H19-high and low infiltration of CD8+ T cells in MALAT1-high groups were associated with worse survival of GC.

CONCLUSIONS

MALAT1 and H19 have the potential to predict the chemotherapy response and clinical outcomes of GC.

Research Progress of Long Non-Coding RNA in Tumor Drug Resistance: A New Paradigm

In the past few decades, chemotherapy has been one of the most effective cancer treatment options. Drug resistance is currently one of the greatest obstacles to effective cancer treatment. Even though drug resistance mechanisms have been extensively investigated, they have not been fully elucidated. Recent genome-wide investigations have revealed the existence of a substantial quantity of long non-coding RNAs (lncRNAs) transcribed from the human genome, which actively participate in numerous biological processes, such as transcription, splicing, epigenetics, the cell cycle, cell differentiation, development, pluripotency, immune microenvironment. The abnormal expression of lncRNA is considered a contributing factor to the drug resistance. Furthermore, drug resistance may be influenced by genetic and epigenetic variations, as well as individual differences in patient treatment response, attributable to polymorphisms in metabolic enzyme genes. This review focuses on the mechanism of lncRNAs resistance to target drugs in the study of tumors with high mortality, aiming to establish a theoretical foundation for targeted therapy.

Brucella abortus triggers the differential expression of immunomodulatory lncRNAs in infected murine macrophages

Introduction

The lncRNAs (long non-coding RNAs) are the most diverse group of non-coding RNAs and are involved in most biological processes including the immune response. While some of them have been recognized for their influence on the regulation of inflammatory activity, little is known in the context of infection by Brucella abortus, a pathogen that presents significant challenges due to its ability to manipulate and evade the host immune system. This study focuses on characterize the expression profile of LincRNA-cox2, Lethe, lincRNA-EPS, Malat1 and Gas5 during infection of macrophages by B. abortus.

Methods

Using public raw RNA-seq datasets we constructed for a lncRNA expression profile in macrophages Brucella-infected. In addition, from public RNA-seq raw datasets of RAW264.7 cells infected with B. abortus we constructed a transcriptomic profile of lncRNAs in order to know the expression of the five immunomodulating lncRNAs studied here at 8 and 24 h post-infection. Finally, we performed in vitro infection assays in RAW264.7 cells and peritoneal macrophages to detect by qPCR changes in the expression of these lncRNAs at first 12 hours post infection, a key stage in the infection cycle where Brucella modulates the immune response to survive.

Results

Our results demonstrate that infection of macrophages with Brucella abortus, induces significant changes in the expression of LincRNA-Cox2, Lethe, LincRNA-EPS, Gas5, and Malat1.

Discussion

The change in the expression profile of these immunomodulatory lncRNAs in response to infection, suggest a potential involvement in the immune evasion strategy employed by Brucella to facilitate its intracellular survival.

Combating drug resistance in hepatocellular carcinoma: No awareness today, no action tomorrow

Hepatocellular carcinoma (HCC), the sixth most common cancer worldwide, is associated with a high degree of malignancy and poor prognosis. Patients with early HCC may benefit from surgical resection to remove tumor tissue and a margin of healthy tissue surrounding it. Unfortunately, most patients with HCC are diagnosed at an advanced or distant stage, at which point resection is not feasible. Systemic therapy is now routinely prescribed to patients with advanced HCC; however, drug resistance has become a major obstacle to the treatment of HCC and exploring purported mechanisms promoting drug resistance remains a challenge. Here, we focus on the determinants of drug resistance from the perspective of non-coding RNAs (ncRNAs), liver cancer stem cells (LCSCs), autophagy, epithelial-mesenchymal transition (EMT), exosomes, ferroptosis, and the tumor microenvironment (TME), with the aim to provide new insights into HCC treatment.

The role of ncRNA in the co-regulation of autophagy and exosome pathways during cancer progression

Since its discovery a few decades ago, autophagy has been recognized as a crucial signaling pathway, linked to the recycling of cellular components in nutrient stress. Autophagy is a two-way sword, playing a dual role in tumorigenesis. In this catabolic process, dysfunctional organelles, biomolecules, and misfolded proteins are sequestered in the autophagosome and sent to the lysosome for degradation. Alongside, there are cellular messengers called exosomes, which are released from cells and are known to communicate and regulate metabolism in recipient cells. Multivesicular bodies (MVB) act as the intricate link between autophagy and exosome pathways. The continuous crosstalk between the two pathways is coordinated and regulated by multiple players among which ncRNA is the emerging candidates. The exosomes carry varied cargo of which non-coding RNA exerts an immediate regulatory effect on recipient cells. ncRNA is known to exhibit dual behavior in both promoting and inhibiting tumor growth. There is increasing evidence for the involvement of ncRNAs' in the regulation of different hallmarks of cancer. Different ncRNAs are involved in the co-regulation of autophagy and exosome pathways and therefore represent a superior therapeutic approach to target cancer chemoresistance. Here, we will discuss the ncRNA involved in regulating autophagy, and exosomes pathways and its relevance in cancer therapeutics.

H1Innovative approaches to combat anti-cancer drug resistance: Targeting lncRNA and autophagy

BACKGROUND

To date, standardizing clinical predictive biomarkers for assessing the response to immunotherapy remains challenging due to variations in personal genetic signatures, tumour microenvironment complexities and epigenetic onco-mechanisms.

MAIN BODY

Early monitoring of key non-coding RNA (ncRNA) biomarkers may help in predicting the clinical efficacy of cancer immunotherapy and come up with standard predictive ncRNA biomarkers. For instance, reduced miR-125b-5p level in the plasma of non-small cell lung cancer patients treated with anti-PD-1 predicts a positive outcome. The level of miR-153 in the plasma of colorectal cancer patients treated with chimeric antigen receptor T lymphocyte (CAR-T) cell therapy may indicate the activation of T-cell killing activity. miR-148a-3p and miR-375 levels may forecast favourable responses to CAR-T-cell therapy in B-cell acute lymphoblastic leukaemia. In cancer patients treated with the GPC3 peptide vaccine, serum levels of miR-1228-5p, miR-193a-5p and miR-375-3p were reported as predictive biomarkers of good response and improved overall survival. Therefore, there is a critical need for further studies to elaborate on the key ncRNA biomarkers that have the potential to predict early clinical responses to immunotherapy.

CONCLUSIONS

This review summarises important predictive ncRNA biomarkers that were reported in cancer patients treated with different immunotherapeutic modalities including monoclonal antibodies, small molecule inhibitors, cancer vaccines and CAR-T cells. In addition, a concise discussion on forthcoming perspectives is provided, outlining technical approaches for the optimal utilisation of immune-modulatory ncRNA biomarkers as predictive tools and therapeutic targets.

Regulatory miRNAs in cancer cell recovery from therapy exposure and its implications as a novel therapeutic strategy for preventing disease recurrence

The desired outcome of cancer therapies is the eradication of disease. This can be achieved when therapy exposure leads to therapy-induced cancer cell death as the dominant outcome. Theoretically, a permanent therapy-induced growth arrest could also contribute to a complete response, which has the potential to lead to remission. However, preclinical models have shown that therapy-induced growth arrest is not always durable, as recovering cancer cell populations can contribute to the recurrence of cancer. Significant research efforts have been expended to develop strategies focusing on the prevention of recurrence. Recovery of cells from therapy exposure can occur as a result of several cell stress adaptations. These include cytoprotective autophagy, cellular quiescence, a reversable form of senescence, and the suppression of apoptosis and necroptosis. It is well documented that microRNAs regulate the response of cancer cells to anti-cancer therapies, making targeting microRNAs therapeutically a viable strategy to sensitization and the prevention of recovery. We propose that the use of microRNA-targeting therapies in prolonged sequence, that is, a significant period after initial therapy exposure, could reduce toxicity from the standard combination strategy, and could exploit new epigenetic states essential for cancer cells to recover from therapy exposure. In a step toward supporting this strategy, we survey the available scientific literature to identify microRNAs which could be targeted in sequence to eliminate residual cancer cell populations that were arrested as a result of therapy exposure. It is our hope that by successfully identifying microRNAs which could be targeted in sequence we can prevent disease recurrence.

Targeting miRNAs and Other Non-Coding RNAs as a Therapeutic Approach: An Update

Since the discovery of the first microRNAs (miRNAs, miRs), the understanding of miRNA biology has expanded substantially. miRNAs are involved and described as master regulators of the major hallmarks of cancer, including cell differentiation, proliferation, survival, the cell cycle, invasion, and metastasis. Experimental data indicate that cancer phenotypes can be modified by targeting miRNA expression, and because miRNAs act as tumor suppressors or oncogenes (oncomiRs), they have emerged as attractive tools and, more importantly, as a new class of targets for drug development in cancer therapeutics. With the use of miRNA mimics or molecules targeting miRNAs (i.e., small-molecule inhibitors such as anti-miRS), these therapeutics have shown promise in preclinical settings. Some miRNA-targeted therapeutics have been extended to clinical development, such as the mimic of miRNA-34 for treating cancer. Here, we discuss insights into the role of miRNAs and other non-coding RNAs in tumorigenesis and resistance and summarize some recent successful systemic delivery approaches and recent developments in miRNAs as targets for anticancer drug development. Furthermore, we provide a comprehensive overview of mimics and inhibitors that are in clinical trials and finally a list of clinical trials based on miRNAs.

Autophagy orchestrates resistance in hepatocellular carcinoma cells

Treatment resistance is one of the major barriers for therapeutic strategies in hepatocellular carcinoma (HCC). Many studies have indicated that chemotherapy and radiotherapy induce autophagy machinery (cell protective autophagy) in HCC cells. In addition, many experiments report a remarkable crosstalk between treatment resistance and autophagy pathways. Thus, autophagy could be one of the key factors enabling tumor cells to hinder induced cell death after medical interventions. Therefore, extensive research on the molecular pathways involved in resistance induction and autophagy have been conducted to achieve the desired therapeutic response. The key molecular pathways related to the therapy resistance are TGF-β, MAPK, NRF2, NF-κB, and non-coding RNAs. In addition, EMT, drug transports, apoptosis evasion, DNA repair, cancer stem cells, and hypoxia could have considerable impact on the hepatoma cell's response to therapies. These mechanisms protect tumor cells against various treatments and many studies have shown that each of them is connected to the molecular pathways of autophagy induction in HCC. Hence, autophagy inhibition may be an effective strategy to improve therapeutic outcome in HCC patients. In this review, we further highlight how autophagy leads to poor response during treatment through a complex molecular network and how it enhances resistance in primary liver cancer. We propose that combinational regimens of approved HCC therapeutic protocols plus autophagy inhibitors may overcome drug resistance in HCC therapy.

Functions and mechanisms of lncRNA MALAT1 in cancer chemotherapy resistance

Chemotherapy is one of the most important treatments for cancer therapy. However, chemotherapy resistance is a big challenge in cancer treatment. Due to chemotherapy resistance, drugs become less effective or no longer effective at all. In recent years, long non-coding RNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) has been found to be associated with the development of chemotherapy resistance, suggesting that MALAT1 may be an important target to overcome chemotherapy resistance. In this review, we introduced the main mechanisms of chemotherapy resistance associated with MALAT1, which may provide new approaches for cancer treatment.

The Roles of Epigenetic Regulation and the Tumor Microenvironment in the Mechanism of Resistance to Systemic Therapy in Hepatocellular Carcinoma

Primary liver cancer is the sixth most common cancer and the third most common cause of cancer-related deaths worldwide. Hepatocellular carcinoma (HCC) is a major histologic type with a poor prognosis owing to the difficulty in early detection, the chemotherapy resistance, and the high recurrence rate of the disease. Despite recent advancements in HCC prevention and diagnosis, over 50% of patients are diagnosed at Barcelona Clinic Liver Cancer Stage B or C. Systemic therapies are recommended for unresectable HCC (uHCC) with major vascular invasion, extrahepatic metastases, or intrahepatic lesions that have a limited response to transcatheter arterial chemoembolization, but the treatment outcome tends to be unsatisfactory due to acquired drug resistance. Elucidation of the mechanisms underlying the resistance to systemic therapies and the appropriate response strategies to solve this issue will contribute to improved outcomes in the multidisciplinary treatment of uHCC. In this review, we summarize recent findings on the mechanisms of resistance to drugs such as sorafenib, regorafenib, and lenvatinib in molecularly targeted therapy, with a focus on epigenetic regulation and the tumor microenvironment and outline the approaches to improve the therapeutic outcome for patients with advanced HCC.

Noncoding RNA-mediated molecular bases of chemotherapy resistance in hepatocellular carcinoma

Despite the significant progress in decreasing the occurrence and mortality of hepatocellular carcinoma (HCC), it remains a public health issue worldwide on the basis of its late presentation and tumor recurrence. To date, apart from surgical interventions, such as surgical resection, liver transplantation and locoregional ablation, current standard antitumor protocols include conventional cytotoxic chemotherapy. However, due to the high chemoresistance nature, most current therapeutic agents show dismal outcomes for this refractory malignancy, leading to disease relapse. Nevertheless, the molecular mechanisms involved in chemotherapy resistance remain systematically ambiguous. Herein, HCC is hierarchically characterized by the formation of primitive cancer stem cells (CSCs), progression of epithelial-mesenchymal transition (EMT), unbalanced autophagy, delivery of extracellular vesicles (EVs), escape of immune surveillance, disruption of ferroptosis, alteration of the tumor microenvironment and multidrug resistance-related signaling pathways that mediate the multiplicity and complexity of chemoresistance. Of note, anecdotal evidence has corroborated that noncoding RNAs (ncRNAs) extensively participate in the critical physiological processes mentioned above. Therefore, understanding the detailed regulatory bases that underlie ncRNA-mediated chemoresistance is expected to yield novel insights into HCC treatment. In the present review, a comprehensive summary of the latest progress in the investigation of chemotherapy resistance concerning ncRNAs will be elucidated to promote tailored individual treatment for HCC patients.

Epigenetic regulation of autophagy in gastrointestinal cancers

The development of novel therapeutic approaches is necessary to manage gastrointestinal cancers (GICs). Considering the effective molecular mechanisms involved in tumor growth, the therapeutic response is pivotal in this process. Autophagy is a highly conserved catabolic process that acts as a double-edged sword in tumorigenesis and tumor inhibition in a context-dependent manner. Depending on the stage of malignancy and cellular origin of the tumor, autophagy might result in cancer cell survival or death during the GICs' progression. Moreover, autophagy can prevent the progression of GIC in the early stages but leads to chemoresistance in advanced stages. Therefore, targeting specific arms of autophagy could be a promising strategy in the prevention of chemoresistance and treatment of GIC. It has been revealed that autophagy is a cytoplasmic event that is subject to transcriptional and epigenetic regulation inside the nucleus. The effect of epigenetic regulation (including DNA methylation, histone modification, and expression of non-coding RNAs (ncRNAs) in cellular fate is still not completely understood. Recent findings have indicated that epigenetic alterations can modify several genes and modulators, eventually leading to inhibition or promotion of autophagy in different cancer stages, and mediating chemoresistance or chemosensitivity. The current review focuses on the links between autophagy and epigenetics in GICs and discusses: 1) How autophagy and epigenetics are linked in GICs, by considering different epigenetic mechanisms; 2) how epigenetics may be involved in the alteration of cancer-related phenotypes, including cell proliferation, invasion, and migration; and 3) how epidrugs modulate autophagy in GICs to overcome chemoresistance.

Introduction of long non-coding RNAs to regulate autophagy-associated therapy resistance in cancer

Autophagy is a lysosomal degradation pathway that depends on various evolutionarily conserved autophagy-related genes (ATGs). Dysregulation of autophagy plays an important role in the occurrence and development of cancer. Chemotherapy, targeted therapy, radiotherapy, and immunotherapy are important treatment options for cancer, which can significantly improve the survival rate of cancer patients. However, the occurrence of therapy resistance results in therapeutic failure and poor prognosis of cancer. Accumulating studies have found that long non-coding RNAs (lncRNAs) are well known as crucial regulators to control autophagy through regulating ATGs and autophagy-associated signaling pathways, including the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway, ultimately mediating chemoresistance and radioresistance. Taken together, this review systematically summarizes and elucidates the pivotal role of lncRNAs in cancer chemoresistance and radioresistance via regulating autophagy. Understanding the specific mechanism of which may provide autophagy-related therapeutic targets for cancer in the future.

Sesquiterpene Lactones Attenuate Paclitaxel Resistance Via Inhibiting MALAT1/STAT3/ FUT4 Axis and P-Glycoprotein Transporters in Lung Cancer Cells

Paclitaxel resistance is a challenging factor in chemotherapy resulting in poor prognosis and cancer recurrence. Signal transducer and activator of transcription factor 3 (STAT3), a key transcription factor, performs a critical role in cancer development, cell survival and chemoresistance, while its inactivation overwhelms drug resistance in numerous cancer types including lung cancer. Additionally, the fucosyltransferase 4 (FUT4) is a crucial enzyme in post-translational modification of cell-surface proteins involved in various pathological conditions such as tumor multidrug resistance (MDR). The P-glycoprotein (P-GP) is the well-known ABC transporter member that imparts drug resistance in different cancer types, most notably paclitaxel resistance in lung cancer cells. LncRNA-MALAT1 exerts a functional role in the cancer development as well as the drug resistance and is linked with STAT3 activation and activity of FUT4. Moreover, STAT3-mediated induction of P-GP is well-documented. Natural compounds of Sesquiterpene Lactone (SL) family are well-known for their anticancer properties with particular emphasis over STAT3 inhibitory capabilities. In this study, we explored the positive correlation of MALAT1 with STAT3 and FUT4 activity in paclitaxel resistant A549 (A549/T) lung cancer cells. Additionally, we investigated the anticancer activity of two well-known members of SLs, alantolactone (ALT) and Brevilin A (Brv-A), in A549/T lung cancer cells. ALT and Brv-A induced apoptosis in A549/T cells. Furthermore, these two natural SLs suppressed MALAT1 expression, STAT3 activation, and FUT4 and P-GP expression which are the hallmarks for paclitaxel resistance in A549 lung cancer cells. The inhibition of MALAT1 enhanced the competence of these SLs members significantly, which accounted for the growth inhibition as well as anti-migratory and anti-invasive effects of ALT and Brv-A. These findings suggest SLs to be the promising agents for overcoming paclitaxel resistance in A549 lung cancer cells.

Autophagy-related long non-coding RNA signature for potential prognostic biomarkers of patients with cervical cancer: a study based on public databases

Background

Metastasis and recurrence are the main causes of death from cervical cancer (CC), thus it is important to identify more effective biomarkers to improve its prognosis. The purpose of our research was to determine the potential role of autophagy-related long non-coding RNA (lncRNA) in CC and to construct an autophagy-related lncRNA signature for survival of CC.

Methods

The lncRNAs in CC were downloaded from The Cancer Genome Atlas (TCGA) database, and autophagy-related lncRNAs were identified through the co-expression of lncRNA genes and autophagy genes. Several autophagy-related lncRNAs with prognostic value (AC012306.2, AL109976.1, ATP2A1-AS1, ILF3-DT, Z83851.2, STARD7-AS1, AC099343.2, AC008771.1, DBH-AS1, and AC097468.3) were identified using univariate and multivariate Cox regression analyses and a prognostic signature was established. The signature effect was detected by univariate Cox regression analysis [hazard ratio (HR) =1.665; 95% confidence interval (CI): 1.331–2.082; P<0.001] and multivariate Cox regression analysis (HR =1.738; 95% CI: 1.359–2.223; P<0.001). A nomogram was drawn by risk score and clinical features.

Results

The prognostic signature could predict the survival of CC by survival-receiver operating characteristic (ROC) curve [area under the curve (AUC) =0.810]. A nomogram was drawn by risk score and clinical features, and its c-index and calibration curve demonstrated that the prognostic signature could independently predict the prognosis of CC (P<0.001). Gene set enrichment analysis (GSEA) confirmed that the genes were significantly enriched in cancer- and autophagy-related pathways (P<0.05).

Conclusions

This 10 autophagy-related lncRNA signature has prognostic potential for CC. More important roles in the CC biology of these lncRNAs may be identified with further study.

The Multiple Function of lncRNA MALAT1 in Cancer Occurrence and Progression

Long non-coding RNAs (lncRNAs) have received particular attention in the last decade due to its engaging in carcinogenesis and tumorigenesis. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a lncRNA that plays physiological and pathological roles in many aspects of genome function as well as biological processes involved in cell development, differentiation, proliferation, invasion, and migration. In this article, we will review the effects of lncRNA MALAT1 on the progression of six prevalent human cancers by focusing on MALAT1 ability to regulate post-transcriptional modification and signaling pathways.

Ultrasound microbubbles-mediated miR-216b affects MALAT1-miRNA axis in non-small cell lung cancer cells

MiR-216b is ectopically expressed in various cancers. Ultrasound microbubbles (UTMBs) are an effective method for miRNA delivery. This article mainly explored the involvement of lncRNA in the effects of UTMBs-mediated miR-216b on non-small cell lung cancer (NSCLC) progression. Expressions and relationship of miR-216b and MALAT1 were examined using quantitative real-time polymerase chain reaction (qRT-PCR), Pearson, TargetScan, and dual-luciferase reporter assay. After the transfection with liposome- or UTMBs-mediated miR-216b mimic (M) or MALAT1 overexpression plasmid alone or together, levels of miR-216b and MALAT1, cell biological behaviors, as well as expressions of apoptosis- and epithelial mesenchymal transition (EMT)-related markers were examined using qRT-PCR, cell functional experiments, and western blot. Besides, we used qRT-PCR to quantify the expressions of multiple downstream miRNAs of MALAT1. MiR-216b expression was weakened yet MALAT1 expression was enhanced in NSCLC tissues, and miR-216b was negatively bound to MALAT1. TargetScan analysis manifested that miR-216b, targeted by MALAT1, was down-regulated in NSCLC cells. UTMBs-mediated miR-216b M further intensified miR-216b level yet weakened cell biological behaviors. The inhibitory effect of UTMBs-mediated miR-216b M on cell biological behaviors and MALAT1 expression was greatly better relative to that of miR-216b M. Moreover, miR-216b restrained the cell biological behaviors by repressing MALAT1 expression. We further manifested that miR-216b facilitated the expressions of apoptosis-related markers, but restrained those of EMT-related markers by repressing MALAT1 expression. Moreover, UTMBs-mediated miR-216b M enhanced the expressions of downstream multiple miRNAs of MALAT1, but this tendency was reversed by co-transfection of overexpressed MALAT1 and miR-216b M. Collectively, UTMBs-mediated miR-216b M restrained NSCLC cell growth by modulating the MALAT1-miRNA axis.

Targeting long non coding RNA by natural products: Implications for cancer therapy

In spite of achieving substantial progress in its therapeutic strategies, cancer-associated prevalence and mortality are persistently rising globally. However, most malignant cancers either cannot be adequately diagnosed at the primary phase or resist against multiple treatments such as chemotherapy, surgery, radiotherapy as well as targeting therapy. In recent decades, overwhelming evidences have provided more convincing words on the undeniable roles of long non-coding RNAs (lncRNAs) in incidence and development of various cancer types. Recently, phytochemical and nutraceutical compounds have received a great deal of attention due to their inhibitory and stimulatory effects on oncogenic and tumor suppressor lncRNAs respectively that finally may lead to attenuate various processes of cancer cells such as growth, proliferation, metastasis and invasion. Therefore, application of phytochemicals with anticancer characteristics can be considered as an innovative approach for treating cancer and increasing the sensitivity of cancer cells to standard prevailing therapies. The purpose of this review was to investigate the effect of various phytochemicals on regulation of lncRNAs in different human cancer and evaluate their capabilities for cancer treatment and prevention.

LncRNA FEZF1-AS1 Promotes Multi-Drug Resistance of Gastric Cancer Cells via Upregulating ATG5

Long non-coding RNAs (lncRNAs) play important roles in human cancers including gastric cancer (GC). Dysregulation of lncRNAs is involved in a variety of pathological activities associated with gastric cancer progression and chemo-resistance. However, the role and molecular mechanisms of FEZF1-AS1 in chemoresistance of GC remain unknown. In this study, we aimed to determine the role of FEZF1-AS1 in chemoresistance of GC. The level of FEZF1-AS1 in GC tissues and GC cell lines was assessed by qRT-PCR. Our results showed that the expression of FEZF1-AS1 was higher in gastric cancer tissues than in adjacent normal tissues. Multivariate analysis identified that high level of FEZF1-AS1 is an independent predictor for poor overall survival. Increased FEZF1-AS1 expression promoted gastric cancer cell proliferation in vitro. Additionally, FEZF1-AS1 was upregulated in chemo-resistant GC tissues. The regulatory effect of FEZF1-AS1 on multi-drug resistance (MDR) in GC cells and the underlying mechanism was investigated. It was found that increased FEZF1-AS1 expression promoted chemo-resistance of GC cells. Molecular interactions were determined by RNA immunoprecipitation (RIP) and the results showed that FEZF1-AS1 regulated chemo-resistance of GC cells through modulating autophagy by directly targeting ATG5. The proliferation and autophagy of GC cells promoted by overexpression of LncFEZF1-AS1 was suppressed when ATG5 was knocked down. Moreover, knockdown of FEZF1-AS1 inhibited tumor growth and increased 5-FU sensitivity in GC cells in vivo. Taken together, this study revealed that the FEZF1-AS1/ATG5 axis regulates MDR of GC cells via modulating autophagy.

Intelligent Bio-Responsive Fluorescent Au-shRNA Complexes for Regulated Autophagy and Effective Cancer Bioimaging and Therapeutics

The long non-coding RNA (lncRNA) MALAT1 acts as an oncogene. RNA interference (RNAi) is an effective method to control the expression of specific genes and can be used for the treatment of tumors, but an effective and safe carrier system is a significant obstacle to gene therapy. Herein, we explored the possibility of constructing an in situ bio-responsive self-assembled fluorescent gold-short hairpin RNA nanocomplex (Au-shRNA NCs) delivery system by co-incubating gold and MALAT1-shRNA for precise hepatocellular carcinoma (HCC) imaging and treatment. Due to the characteristics of the cancer microenvironment, Au-shRNA NCs self-assembled in HCC cells (HepG2) but did not occur in control cells (L02) under the same conditions. The in situ bio-responsive self-assembled Au-shRNA NCs delivery system can realize cancer cell bioimaging and promote cell uptake and endosomal escape mechanism, thereby realizing effective transfection. They effectively silenced target gene MALAT1, and with the downregulation of MALAT1, we found that several molecules involved in autophagic flux were also regulated. In vitro and tumor-bearing mouse model experiments demonstrated that the as-prepared fluorescent Au-shRNA NCs can readily realize tumor bioimaging and effectively silence the target gene MALAT1, and those autophagy-related pathway molecules were significantly downregulated, thereby exerting a tumor suppressor efficiency. This raises the possibility of realizing accurate multi-scale bio-imaging from the molecular-level with targeted gene-recognition to cancer cell imaging as well as in vivo tumor tissue imaging for the simultaneous precise cancer therapy.

Long non-coding RNAs and circular RNAs in tumor angiogenesis: From mechanisms to clinical significance

Long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) execute a wide array of functions in physiological and pathological processes, including tumor progression. Angiogenesis, an elaborate multistep process driving new blood vessel formation, accelerates cancer progression by supplying nutrients and energy. Dysregulated lncRNAs and circRNAs can reportedly impact cancer progression by influencing angiogenesis. However, the expanding landscape of lncRNAs and circRNAs in tumor progression-dependent angiogenesis remains largely unknown. This review summarizes the major functions of angiogenic lncRNAs (Angio-LncRs) and angiogenic circRNAs (termed Angio-CircRs) and their cancer mechanisms. Moreover, we highlight the commonalities of lncRNAs and circRNAs in epigenetic, transcriptional, and post-transcriptional regulation as well as illustrate how Angio-LncRs and Angio-CircRs induce cancer onset and progression. We also discuss their potential clinical applications in diagnosis, prognosis, and anti-angiogenic therapies.

MALAT-1 is Associated with the Doxorubicin Resistance in U-2OS Osteosarcoma Cells

Purpose

Our study aimed to investigate the relationship between MALAT-1 (metastasis-associated lung adenocarcinoma transcript 1) expression and the chemotherapy drug resistance in osteosarcoma.

Methods

The U-2OS osteosarcoma cell line was selected for the experiment. The cells were treated with methotrexate, doxorubicin, cisplatin, and ifosfamide, respectively. RT-PCR was applied to detect the MALAT-1 expression in cells. The doxorubicin-resistant cell line was constructed. The cells were divided into doxorubicin-sensitivity group (DS/shCtrl), doxorubicin-resistance group (DR/shCtrl) and shMALAT1-doxorubicin-resistance group (DR/shMALAT1). The colony formation assay and 5-ethynyl-2ʹ-deoxyuridine (EdU) assay were used to detect cell proliferation. PI staining was used to detect the cell cycle. Transwell assay and wound healing assay were used to observe the migration and invasion ability. Annexin V-FITC assay was used to detect cell apoptosis. Western blot was used to detect the protein expression and potential mechanism. The impacts of MALAT-1 expression were verified in vivo.

Results

The MALAT-1 was upregulated in the doxorubicin-resistant U-2OS osteosarcoma cells. Downregulating MALAT-1 in the doxorubicin-resistant cells inhibited the proliferation, migration, and invasiveness, increased the ratio of cells in the G0/G1 phase, promoted apoptosis. In the doxorubicin-resistant U-2OS cells, the extracellular regulated protein kinases (ERK) phosphorylation was declined, which could be reversed by downregulating MALAT-1. In vivo assay indicated that the growth of doxorubicin-resistant solid osteosarcoma could be suppressed by downregulating MALAT-1.

Conclusion

Our study provides evidence that doxorubicin may upregulate MALAT-1 in osteosarcoma. Downregulating MALAT-1 in the doxorubicin resistance U-2OS cells could reverse the resistance and may improve chemotherapeutic efficiency. Some conclusions in previous literature may be one-sided.

Long non-coding RNAs as the critical regulators of doxorubicin resistance in tumor cells

Resistance against conventional chemotherapeutic agents is one of the main reasons for tumor relapse and poor clinical outcomes in cancer patients. Various mechanisms are associated with drug resistance, including drug efflux, cell cycle, DNA repair and apoptosis. Doxorubicin (DOX) is a widely used first-line anti-cancer drug that functions as a DNA topoisomerase II inhibitor. However, DOX resistance has emerged as a large hurdle in efficient tumor therapy. Furthermore, despite its wide clinical application, DOX is a double-edged sword: it can damage normal tissues and affect the quality of patients’ lives during and after treatment. It is essential to clarify the molecular basis of DOX resistance to support the development of novel therapeutic modalities with fewer and/or lower-impact side effects in cancer patients. Long non-coding RNAs (lncRNAs) have critical roles in the drug resistance of various tumors. In this review, we summarize the state of knowledge on all the lncRNAs associated with DOX resistance. The majority are involved in promoting DOX resistance. This review paves the way to introducing an lncRNA panel marker for the prediction of the DOX response and clinical outcomes for cancer patients.

Long Noncoding RNAs and Human Liver Disease

Long noncoding RNAs (lncRNAs) are pervasively transcribed in the genome, exhibit a diverse range of biological functions, and exert effects through a variety of mechanisms. The sheer number of lncRNAs in the human genome has raised important questions about their potential biological significance and roles in human health and disease. Technological and computational advances have enabled functional annotation of a large number of lncRNAs. Though the number of publications related to lncRNAs has escalated in recent years, relatively few have focused on those involved in hepatic physiology and pathology. We provide an overview of evolving lncRNA classification systems and characteristics and highlight important advances in our understanding of the contribution of lncRNAs to liver disease, with a focus on nonalcoholic steatohepatitis, hepatocellular carcinoma, and cholestatic liver disease. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 17 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

LncRNA-MALAT1/miRNA-204-5p/Smad4 Axis Regulates Epithelial-Mesenchymal Transition, Proliferation and Migration of Lens Epithelial Cells

MATERIALS AND METHODS

LECs were cultured and induced with TGF-β2 (10 ng/mL). SiRNA against MALAT1 (Si-MALAT1) was transfected into LECs to knockdown the expression of MALAT1. To overexpress or knockdown miR-204-5p, miR-204-5p mimics (miR-204-5p mimics) and anti-miR-204-5p (miR-204-5p inhibitor) were transfected into LECs. We used RNA FISH to identify the location of MALAT1. RNA levels of MALAT1 and miR-204-5p were analyzed by RT-qPCR. Additionally, target protein levels of Smad4, epithelial differentiation and mesenchymal markers were analyzed with Western blot. We employed EdU Labeling to measured cell proliferation and performed Transwell Assay to analyze the cell migration. Dual-luciferase reporter assays in LECs were conducted to verify whether miRNA-204-5p was negatively regulated by MALAT1 and Smad4 was a direct target of miR-204-5p.

RESULTS

The expression of MALAT1 was upregulated in PCO specimens. MALAT1 was overexpressed in TGF-β2 induced LECs, and the knockdown of MALAT1 could attenuate TGF-β2 induced EMT. Besides, the upregulation of MALAT1 was correlated with the downregulation of miR-204-5p and upregulation of Smad4. Importantly, MALAT1 was revealed to be located in the cytoplasm of LECs. Furthermore, luciferase reporter assays confirmed that MALAT1 could negatively regulate the expression of miR-204-5p and then regulate its direct target Smad4. Finally, the knockdown of MALAT1 could inhibit the EMT, proliferation, and migration of LECs; however, those can be reversed by anti-miR-204-5p.

CONCLUSIONS

Our findings reveal that MALAT1 may regulate EMT, proliferation, and migration of LECs as a ceRNA by "sponging" miR-204-5p and targeting Smad4, and serve as a promising therapeutic target in preventing PCO.

The Role of Non-Coding RNAs in the Sorafenib Resistance of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the second most common cause of cancer-related death. Sorafenib is approved by the U.S. Food and Drug Administration to be a first-line chemotherapy agent for patients with advanced HCC. A portion of advanced HCC patients can benefit from the treatment with sorafenib, but many patients ultimately develop sorafenib resistance, leading to a poor prognosis. The molecular mechanisms of sorafenib resistance are sophisticated and indefinite. Notably, non-coding RNAs (ncRNAs), which include long ncRNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs), are critically participated in the occurrence and progression of tumors. Moreover, growing evidence has suggested that ncRNAs are crucial regulators in the development of resistance to sorafenib. Herein, we integrally and systematically summarized the molecular mechanisms and vital role of ncRNAs impact sorafenib resistance of HCC, and ultimately explored the potential clinical administrations of ncRNAs as new prognostic biomarkers and therapeutic targets for HCC.

CircFBXL5 promotes the 5-FU resistance of breast cancer via modulating miR-216b/HMGA2 axis

Background

Circular RNAs (circRNAs) have been confirmed to be relevant to the 5-fluorouracil (5-FU) resistance of breast cancer. Nevertheless, how and whether circRNA F-box and leucine-rich repeat protein 5 (circFBXL5) regulates the 5-FU resistance of breast cancer is uncertain. This study aims to explore the function and mechanism of circFBXL5 in the 5-FU resistance of breast cancer.

Methods

Thirty nine paired breast cancer and normal tissues were harvested. circFBXL5, microRNA-216b (miR-216b) and high-mobility group AT-hook 2 (HMGA2) abundances were examined via quantitative reverse transcription polymerase chain reaction or western blot. Cell viability, 5-FU resistance, migration, invasion, and apoptosis were tested via cell counting kit-8 assay, wound healing analysis, transwell analysis, and flow cytometry. The relationship of miR-216b and circFBXL5 or HMGA2 was tested via dual-luciferase reporter analysis and RNA pull-down assay. The impact of circFBXL5 on breast cancer tumor growth in vivo was analyzed via xenograft model.

Results

circFBXL5 was highly expressed in breast cancer tissues and cells, and was more upregulated in 5-FU-resistant breast cancer cells. Function experiments showed that circFBXL5 knockdown inhibited the 5-FU resistance of breast cancer by inhibiting cell migration, invasion and promoting apoptosis. In the terms of mechanism, miR-216b could be sponged by circFBXL5, and its inhibitor could also reverse the influence of circFBXL5 silencing on the 5-FU resistance of breast cancer cells. In addition, HMGA2 was a target of miR-216b, and its overexpression also reversed the regulation of miR-216b overexpression on the 5-FU resistance of breast cancer. Furthermore, circFBXL5 interference declined breast cancer tumor growth in xenograft model.

Conclusion

Our data showed that circFBXL5 could promote the 5-FU resistance of breast cancer by regulating miR-216b/HMGA2 axis.

MicroRNAs as the critical regulators of cisplatin resistance in gastric tumor cells

Combined chemotherapeutic treatment is the method of choice for advanced and metastatic gastric tumors. However, resistance to chemotherapeutic agents is one of the main challenges for the efficient gastric cancer (GC) treatment. Cisplatin (CDDP) is used as an important regimen of chemotherapy for GC which induces cytotoxicity by interfering with DNA replication in cancer cells and inducing their apoptosis. Majority of patients experience cisplatin-resistance which is correlated with tumor metastasis and relapse. Moreover, prolonged and high-dose cisplatin administrations cause serious side effects such as nephrotoxicity, ototoxicity, and anemia. Since, there is a high rate of recurrence after CDDP treatment in GC patients; it is required to clarify the molecular mechanisms associated with CDDP resistance to introduce novel therapeutic methods. There are various cell and molecular processes associated with multidrug resistance (MDR) including drug efflux, detoxification, DNA repair ability, apoptosis alteration, signaling pathways, and epithelial-mesenchymal transition (EMT). MicroRNAs are a class of endogenous non-coding RNAs involved in chemo resistance of GC cells through regulation of all of the MDR mechanisms. In present review we have summarized all of the miRNAs associated with cisplatin resistance based on their target genes and molecular mechanisms in gastric tumor cells. This review paves the way of introducing a miRNA-based panel of prognostic markers to improve the efficacy of chemotherapy and clinical outcomes in GC patients. It was observed that miRNAs are mainly involved in cisplatin response of gastric tumor cells via regulation of signaling pathways, autophagy, and apoptosis.

New epigenetic players in stroke pathogenesis: From non-coding RNAs to exosomal non-coding RNAs

Non-coding RNAs (ncRNAs) have critical role in the pathophysiology as well as recovery after ischemic stroke. ncRNAs, particularly microRNAs, and the long non-coding RNAs (lncRNAs) are critical for angiogenesis and neuroprotection, and they have been suggested to be therapeutic, diagnostic and prognostic tools in cerebrovascular diseases, including stroke. Moreover, exosomes have been considered as nanocarriers capable of transferring various cargos, such as lncRNAs and miRNAs to recipient cells, with prominent inter-cellular roles in the mediation of neuro-restorative events following strokes and neural injuries. In this review, we summarize the pathogenic role of ncRNAs and exosomal ncRNAs in the stroke.

Long noncoding RNA network: Novel insight into hepatocellular carcinoma metastasis (Review)

Hepatocellular carcinoma (HCC) is one of the most common, aggressive malignancies with poor prognosis and high mortality. Although great progress has been made in recent decades, overall survival of HCC patients remains unsatisfactory due to high recurrence and metastasis. Accordingly, understanding and clarifying the underlying molecular mechanisms of metastasis has become increasingly important. Recently, accumulated reports have supported that long noncoding RNAs (lncRNAs) are dysregulated in HCC and are involved in various pivotal biological processes, including metastasis. The aim of this review was to investigate the dysregulation of lncRNAs in HCC and their function as oncogenes or tumour suppressors. Furthermore, reciprocal regulatory networks between lncRNAs and various molecules that were identified in HCC metastasis, including regulating epithelial-mesenchymal transition (EMT), controlling metastasis-associated genes, and regulating tumour angiogenesis were examined. Numerous reports and information on lncRNAs may help identify lncRNAs that are potential novel diagnostic markers, prognostic markers and therapeutic targets.

Long Noncoding RNA LINC01518 Modulates Proliferation and Migration in TGF-β1-Treated Human Tenon Capsule Fibroblast Cells Through the Regulation of hsa-miR-216b-5p

In this study, we investigated the expression and functions of long noncoding RNAs (LncRNAs) of LINC01518 in an in vitro model of TGF-β1-treated human Tenon capsule fibroblast (HTF) cells. qRT-PCR was used to examine LINC01518 expression in in situ human glaucoma tissues, and in vitro HTF cells treated with TGF-β1. Lentivirus-mediated LINC01518 knockdown was performed in HTF cells to investigate its effect on TGF-β1-induced cell proliferation, migration and autophagy signaling pathway. The potential ceRNA candidate of LINC01518, hsa-miR-216b-5p, was probed by dual-luciferase assay and qRT-PCR. Hsa-miR-216b-5p was also knocked down in LINC01518-downregulated HTF cells to investigate the function of this lncRNA-miRNA epigenetic axis in TGF-β1-treated HTF cells. LINC01518 was upregulated in human glaucoma tissues and cultured HTF cells. LINC01518 downregulation significantly suppressed TGF-β1-induced cell proliferation, migration and autophagy signaling pathway in HTF cells. Hsa-miR-216b-5p was confirmed to be a ceRNA target of LINC01518. Knocking down hsa-miR-216b-5p reversed the suppressing effects of LINC01518 downregulation in TGF-β1-treated HTF cells. Our study demonstrated that LINC01518 is a functional factor in regulating proliferation and migration in TGF-β1-treated HTF cells, and hsa-miR-216b -5p may also be involved. Targeting the epigenetic axis of LINC01518/hsa-miR-216b-5p may provide new insight into the pathological development of human glaucoma.

The Upregulation of a Novel Long Noncoding RNA AK097647 Promotes Enterovirus 71 Replication and Decreases IFN-λ1 Secretion

BACKGROUND

Enterovirus 71 (EV71) infects millions of children every year in China and has become a challenge to public health. However, there is no effective treatment for EV71 infection. Long noncoding RNAs (lncRNAs) have been found to play various roles in virus replication and infection.

OBJECTIVE

We aimed to explore the role of a novel long noncoding RNA AK097647 (lncRNA-AK097647) during EV71 infection.

METHODS

To assess the role of lncRNA-AK097647 during EV71 infection, siRNAs were used to silence lncRNA-K097647 expression. RT-qPCR assay and Western blotting were applied to measure the mRNA and protein levels of EV71 VP1 and the phosphorylation of NF-κB. ELISA was used to detect the level of IFN-λ1 expression.

RESULTS

The novel lncRNA-AK097647 was upregulated in human rhabdomyosarcoma cells and the blood of hand, foot, and mouth disease patients infected with EV71, as demonstrated by RT-qPCR. Interestingly, RNAi-mediated knockdown of lncRNA-AK097647 dramatically increased the level of IFN-λ1 expression, resulting in the suppression of EV71 replication. In contrast, overexpression of lncRNA-AK097647 decreased the level of IFN-λ1 expression and resulted in increased EV71 replication. In addition, we found that lncRNA-AK097647 could inhibit the phosphorylation of NF-κB.

CONCLUSION

These results suggest a novel mechanism by which EV71 evades the IFN-mediated host antiviral response by increasing lncRNA-AK097647 expression.

Hypoxia-Induced MALAT1 Promotes the Proliferation and Migration of Breast Cancer Cells by Sponging MiR-3064-5p

Hypoxia, a common process during tumor growth, can lead to tumor aggressiveness and is tightly associated with poor prognosis. Long noncoding RNAs (lncRNAs) are long ribonucleotides (>200 bases) with limited ability to translate proteins, and are known to affect many aspects of cellular function. One of their regulatory mechanisms is to function as a sponge for microRNA (miRNA) to modulate its biological functions. Previously, MALAT1 was identified as a hypoxia-induced lncRNA. However, the regulatory mechanism and functions of MALAT1 in breast cancer are still unclear. Therefore, we explored whether MALAT1 can regulate the functions of breast cancer cells through miRNAs. Our results showed the expression levels of MALAT1 were significantly up-regulated under hypoxia and regulated by HIF-1α and HIF-2α. Next, in contrast to previous reports, nuclear and cytoplasmic fractionation assays and fluorescence in situ hybridization indicated that MALAT1 was mainly located in the cytoplasm. Therefore, the labeling of MALAT1 as a nuclear marker should be done with the caveat. Furthermore, expression levels of miRNAs and RNA immunoprecipitation using antibody against AGO2 showed that MALAT1 functioned as a sponge of miRNA miR-3064-5p. Lastly, functional assays revealed that MALAT1 could promote cellular migration and proliferation of breast cancer cells. Our findings provide evidence that hypoxia-responsive long non-coding MALAT1 could be transcriptionally activated by HIF-1α and HIF-2α, act as a miRNA sponge of miR-3064-5p, and promote tumor growth and migration in breast cancer cells. These data suggest that MALAT1 may be a candidate for therapeutic targeting of breast cancer progression.

An autophagy-related long non-coding RNA prognostic signature accurately predicts survival outcomes in bladder urothelial carcinoma patients

In this study, we analyzed the prediction accuracy of an autophagy-related long non-coding RNA (lncRNA) prognostic signature using bladder urothelial carcinoma (BLCA) patient data from The Cancer Genome Atlas (TCGA) database. Univariate and multivariate Cox regression analyses showed significant correlations between five autophagy-related lncRNAs, LINC02178, AC108449.2, Z83843.1, FAM13A-AS1 and USP30-AS1, and overall survival (OS) among BCLA patients. The risk scores based on the autophagy-related lncRNA prognostic signature accurately distinguished high- and low-risk BCLA patients that were stratified according to age; gender; grade; and AJCC, T, and N stages. The autophagy-related lncRNA signature was an independent prognostic predictor with an AUC value of 0.710. The clinical nomogram with the autophagy-related lncRNA prognostic signature showed a high concordance index of 0.73 and accurately predicted 1-, 3-, and 5-year survival times among BCLA patients in the high- and low-risk groups. The lncRNA-mRNA co-expression network contained 77 lncRNA-mRNA links among 5 lncRNAs and 49 related mRNAs. Gene set enrichment analysis showed that cancer- and autophagy-related pathways were significantly enriched in the high-risk group, and immunoregulatory pathways were enriched in the low-risk group. These findings demonstrate that an autophagy-related lncRNA signature accurately predicts the prognosis of BCLA patients.

Knockdown of LncRNA CRNDE suppresses proliferation and P-glycoprotein-mediated multidrug resistance in acute myelocytic leukemia through the Wnt/β-catenin pathway

Mechanisms involved in non-coding RNAs have been implicated in multidrug resistance (MDR) of acute myeloid leukemia (AML). Long non-coding RNA (lncRNAs) colorectal neoplasia differentially expressed (CRNDE) is reported to be involved in the malignant progression in AML. The purpose of the present study is to explore the roles and potential molecular mechanism of CRNDE in the MDR in AML. In our study, we confirmed that the expression of CRNDE was significantly up-regulated in patients with AML, especially in AML patients after adriamycin (ADR)-based chemotherapy. Spearman correlation analysis showed a positive correlation between the levels of CRNDE and MDR1 in AML patients after ADR-based chemotherapy. Moreover, CRNDE was up-regulated in AML cells, especially in ADR-resistant AML cells. Multidrug resistance protein 1 (MDR1)/p-glycoprotein (P-gp) levels were significantly increased in ADR-resistant AML cells, compared with parental AML cells. CRNDE down-regulation inhibited cell proliferation, promoted apoptosis, reduced Ki67 expression and enhanced cleaved caspase-3 expression in AML and ADR-resistant AML cells. In addition, CRNDE knockdown led to down-regulation of P-gp/MDR1, β-catenin, c-Myc and cyclinD1 expression, and enhanced the drug sensitivity to ADR in ADR-resistant AML cells. In conclusion, knockdown of CRNDE suppresses proliferation and P-gp-mediated MDR in ADR-resistant AML cells via inhibiting the Wnt/β-catenin pathway, suggesting that repression of CRNDE might be a therapeutic target to reverse MDR of ADR-resistant AML cells.

Construction and validation of an autophagy-related long noncoding RNA signature for prognosis prediction in kidney renal clear cell carcinoma patients

Purpose

The purpose of this study was to identify autophagy‐associated long noncoding RNAs (ARlncRNAs) using the kidney renal clear cell carcinoma (KIRC) patient data from The Cancer Genome Atlas (TCGA) database and to construct a prognostic risk‐related ARlncRNAs signature to accurately predict the prognosis of KIRC patients.

Methods

The KIRC patient data were originated from TCGA database and were classified into a training set and testing set. Seven prognostic risk‐related ARlncRNAs, identified using univariate, lasso, and multivariate Cox regression analysis, were used to construct prognostic risk‐related signatures. Kaplan–Meier curves and receiver operating characteristic (ROC) curves as well as independent prognostic factor analysis and correlation analysis with clinical characteristics were utilized to evaluate and verify the specificity and sensitivity of the signature in training set and testing set, respectively. Two nomograms were established to predict the probable 1‐, 3‐, and 5‐year survival of the KIRC patients. In addition, the lncRNA‐mRNA co‐expression network was constructed and Gene Ontology (GO) enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to identify biological functions of ARlncRNAs.

Results

We constructed and verified a prognostic risk‐related ARlncRNAs signature in training set and testing set, respectively. We found the survival time of KIRC patients with low‐risk scores was significantly better than those with high‐risk scores in training set and testing set. ROC curves suggested that the area under the ROC (AUC) value for prognostic risk score signature was 0.81 in training set and 0.705 in testing set. And AUC values corresponding to 1‐, 3‐, and 5 years of OS were 0.809, 0.753, and 0.794 in training set and 0.698, 0.682, and 0.754 in testing set, respectively. We established the two nomograms that confirmed high C‐index and accomplished good prediction accuracy.

Conclusions

We constructed a prognostic risk‐related ARlncRNAs signature that could accurately predict the prognosis of KIRC patients.

Long non-coding RNAs in motor neuron development and disease

Long non-coding RNAs (lncRNAs) are RNAs that exceed 200 nucleotides in length and that are not translated into proteins. Thousands of lncRNAs have been identified with functions in processes such as transcription and translation regulation, RNA processing, and RNA and protein sponging. LncRNAs show prominent expression in the nervous system and have been implicated in neural development, function and disease. Recent work has begun to report on the expression and roles of lncRNAs in motor neurons (MNs). The cell bodies of MNs are located in cortex, brainstem or spinal cord and their axons project into the brainstem, spinal cord or towards peripheral muscles, thereby controlling important functions such as movement, breathing and swallowing. Degeneration of MNs is a pathological hallmark of diseases such as amyotrophic lateral sclerosis and spinal muscular atrophy. LncRNAs influence several aspects of MN development and disruptions in these lncRNA-mediated effects are proposed to contribute to the pathogenic mechanisms underlying MN diseases (MNDs). Accumulating evidence suggests that lncRNAs may comprise valuable therapeutic targets for different MNDs. In this review, we discuss the role of lncRNAs (including circular RNAs [circRNAs]) in the development of MNs, discuss how lncRNAs may contribute to MNDs and provide directions for future research.

The Biological Roles of lncRNAs and Future Prospects in Clinical Application

Chemo and radiation therapies are the most commonly used therapies for cancer, but they can induce DNA damage, resulting in the apoptosis of host cells. DNA double-stranded breaks (DSBs) are the most lethal form of DNA damage in cells, which are constantly caused by a wide variety of genotoxic agents, both environmentally and endogenously. To maintain genomic integrity, eukaryotic organisms have developed a complex mechanism for the repair of DNA damage. Researches reported that many cellular long noncoding RNAs (lncRNAs) were involved in the response of DNA damage. The roles of lncRNAs in DNA damage response can be regulated by the dynamic modification of N6-adenosine methylation (m6A). The cellular accumulation of DNA damage can result in various diseases, including cancers. Additionally, lncRNAs also play roles in controlling the gene expression and regulation of autophagy, which are indirectly involved with individual development. The dysregulation of these functions can facilitate human tumorigenesis. In this review, we summarized the origin and overview function of lncRNAs and highlighted the roles of lncRNAs involved in the repair of DNA damage.

The AMPK-mTOR axis requires increased MALAT1 expression for promoting granulosa cell proliferation in endometriosis

Endometriosis is a common reproductive disorder in women, with a global prevalence of 10-15%. Long noncoding RNAs (lncRNAs) are critical to gene transcription, cell cycle modulation and immune response. The lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) reportedly mediates autophagy of endometrial stromal cells in endometriosis. The present study aimed to evaluate the role and mechanism of MALAT1 in granulosa cells (GCs) in endometriosis. Consequently, MALAT1 expression was upregulated in GCs obtained from patients with endometriosis and in the steroidogenic human granulosa-like tumor cell line KGN. However, MALAT1 knockdown consequently decreased the proliferation and viability of these cells, as determined by MTT and 5-ethynyl-2'-deoxyuridine staining assays. Both Annexin V-fluorescein isothiocyanate/propidium iodide flow cytometry and western blotting performed to detect proapoptotic factors indicated that MALAT1 depletion might promote KGN cell apoptosis. Furthermore, MALAT1 knockdown increased GC autophagy, as evidenced by microtubule-associated protein 1A/1B-light chain 3 (LC3) cleavage upregulation and p62 degradation. In addition, although 5'-AMP-activated protein kinase (AMPK) mRNA expression and protein levels decreased in GCs obtained from patients with endometriosis and KGN cells, MALAT1 knockdown restored AMPK levels. However, addition of BML-275 (MALAT1 inhibitor) to MALAT1-knockdown KGN cells recovered their viability and proliferative capacity and simultaneously reduced their apoptotic and autophagic capacity. Therefore, MALAT1 may regulate GC proliferation via AMPK-mTOR-mediated cell apoptosis and autophagy.

Long Non-Coding RNAs: Potential Biomarkers and Targets for Hepatocellular Carcinoma Therapy and Diagnosis

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide. Increasing studies showed that long non-coding RNAs (lncRNAs), a novel class of RNAs that are greater than 200 nucleotides in length but lack the ability to encode proteins, exert crucial roles in the occurrence and progression of HCC. LncRNAs promote the proliferation, migration, invasion, autophagy, and apoptosis of tumor cells by regulating downstream target gene expression and cancer-related signaling pathways. Meanwhile, lncRNA can be used as biomarkers to predict the efficacy of HCC treatment strategies, such as surgery, radiotherapy, chemotherapy, and immunotherapy, and as a potential individualized tool for HCC diagnosis and treatment. In this review, we overview up-to-date findings on lncRNAs as potential biomarkers for HCC surgery, radiotherapy, chemotherapy resistance, target therapy, and immunotherapy, and discuss the potential clinical application of lncRNA as tools for HCC diagnosis and treatment.