The Emerging Role of Long Non-Coding RNAs in the Metastasis of Hepatocellular Carcinoma

Functional long non-coding RNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent human malignancy with high morbidity worldwide. Hepatocarcinogenesis is a complex multistep process, and its underlying molecular mechanisms remain largely unknown. Recently, long non-coding RNAs (lncRNAs), a class of newly discovered molecules, have been revealed as essential regulators in the development of HCC. HCC-associated lncRNAs affect multiple malignant phenotypes by modulating gene expression or protein activity. Moreover, the dysregulation of lncRNAs in the liver is also associated with diseases predisposing to HCC, such as chronic viral infection, nonalcoholic steatohepatitis, and liver fibrosis/cirrhosis. A deeper understanding of the lncRNA regulatory network in the multistep processes of HCC development will provide new insights into the diagnosis and treatment of HCC. In this review, we introduce the biogenesis and function of lncRNAs and summarize recent knowledge on how lncRNAs regulate the malignant hallmarks of HCC, such as uncontrolled cell proliferation, resistance to cell death, metabolic reprogramming, immune escape, angiogenesis, and metastasis. We also review emerging insights into the role of lncRNAs in HCC-associated liver diseases. Finally, we discuss the potential applications of lncRNAs as early diagnostic biomarkers and therapeutic targets.

Long Non-Coding RNA DARS-AS1 Contributes to Prostate Cancer Progression Through Regulating the MicroRNA-628-5p/MTDH Axis

Purpose

DARS antisense RNA 1 (DARS-AS1) is a long non-coding RNA that has been validated as a critical regulator in several human cancer types. Our study aimed to determine the expression profile of DARS-AS1 in prostate cancer (PCa) tissues and cell lines. Functional experiments were conducted to explore the detailed roles of DARS-AS1 in regulating PCa carcinogenesis. Furthermore, the detailed mechanisms by which DARS-AS1 regulates the oncogenicity of PCa cells were uncovered.

Methods

Reverse transcription quantitative polymerase chain reaction was performed to analyze DARS-AS1 expression in PCa tissues and cell lines. Cell Counting Kit-8 assays, flow cytometry analyses, Transwell assays, and tumor xenograft experiments were conducted to determine the regulatory effects of DARS-AS1 knockdown on the malignant phenotype of PCa cells. Bioinformatics analysis was performed to identify putative microRNAs (miRNAs) targeting DARS-AS1, and the direct interaction between DARS-AS1 and miR-628-5p was verified using RNA immunoprecipitation and luciferase reporter assays.

Results

DARS-AS1 was highly expressed in PCa tissues and cell lines. In vitro functional experiments demonstrated that DARS-AS1 depletion suppressed PCa cell proliferation, promoted cell apoptosis, and restricted cell migration and invasion. In vivo studies revealed that the downregulation of DARS-AS1 inhibited PCa tumor growth in nude mice. Mechanistic investigation verified that DARS-AS1 functioned as an endogenous miR-628-5p sponge in PCa cells and consequently promoted the expression of metadherin (MTDH). Furthermore, the involvement of miR-628-5p/MTDH axis in DARS-AS1-mediated regulatory actions in PCa cells was verified using rescue experiments.

Conclusion

DARS-AS1 functioned as a competing endogenous RNA in PCa by adsorbing miR-628-5p and thereby increasing the expression of MTDH, resulting in enhanced PCa progression. The identification of a novel DARS-AS1/miR-628-5p/MTDH regulatory network in PCa cells may offer a new theoretical basis for the development of promising therapeutic targets.

Long non‑coding RNA MKLN1‑AS aggravates hepatocellular carcinoma progression by functioning as a molecular sponge for miR‑654‑3p, thereby promoting hepatoma‑derived growth factor expression

Long non‑coding RNAs (lncRNAs) have recently gained attention due to their important roles in human cancer types, such as breast and gastric cancer. The present study measured alterations in muskelin 1 antisense RNA (MKLN1‑AS) expression in hepatocellular carcinoma (HCC) and evaluated its clinical value in patients with HCC. Additionally, the current study investigated the effects of MKLN1‑AS on the malignant features of HCC cells. The detailed molecular mechanisms underlying the cancer‑promoting activities of MKLN1‑AS in HCC cells were also elucidated. MKLN1‑AS expression in HCC tissues and cell lines was detected using reverse‑transcription quantitative PCR (RT‑qPCR). Cell Counting Kit‑8 assays and flow cytometry were used to determine the roles of MKLN1‑AS in HCC cell proliferation and apoptosis. Migration and invasion assays, as well as tumor xenograft experiments were conducted to analyze migration and invasion in vitro and tumor growth in vivo, respectively. The interaction among microRNA‑654‑3p (miR‑654‑3p), MKLN1‑AS and hepatoma‑derived growth factor (HDGF) in HCC was investigated using luciferase reporter assay, RNA immunoprecipitation assay, RT‑qPCR, western blotting and rescue experiments. MKLN1‑AS was upregulated in HCC tissues and cell lines, and a high MKLN1‑AS expression was associated with shorter overall survival and disease‑free survival in patients with HCC. Functionally, the knockdown of MKLN1‑AS impaired HCC cell proliferation, migration and invasion, as well as induced cell apoptosis in vitro. Knockdown of MKLN1‑AS expression also inhibited cell proliferation in vivo. The results indicated that MKLN1‑AS functioned as a competing endogenous RNA by sponging miR‑654‑3p in HCC cells. Additionally, miR‑654‑3p targeting of HDGF was positively modulated by MKLN1‑AS, and miR‑654‑3p knockdown partially abrogated this effect. Rescue experiments demonstrated that knockdown of miR‑654‑3p and overexpression of HDGF both abolished MKLN1‑AS knockdown‑induced cellular processes in HCC. In summary, MKLN1‑AS induced pro‑oncogenic effects during HCC progression by serving as a molecular sponge for miR‑654‑3p to increase HDGF expression. Therefore, the MKLN1‑AS/miR‑654‑3p/HDGF axis may offer a novel target for the diagnosis, prognosis, prevention and treatment of HCC.

PI3K/AKT/mTOR pathway-related long non-coding RNAs: roles and mechanisms in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common tumors worldwide with high prevalence and lethality. The oncogenic phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway is a classic dysregulated pathway involved in the pathogenesis of HCC. However, the underlying mechanism for how PI3K/AKT/mTOR pathway aberrantly activates HCC has not been entirely elucidated. The recognition of the functional roles of long non-coding RNAs (lncRNAs) in PI3K/AKT/mTOR signaling axis sheds light on a new dimension to our understanding of hepatocarcinogenesis. In this review, we comprehensively summarize 67 dysregulated PI3K/AKT/mTOR pathway-related lncRNAs in HCC. Many studies have indicated that the 67 dysregulated lncRNAs show oncogenic or anti-oncogenic effects in HCC by regulation on epigenetic, transcriptional and post-transcriptional levels and they play pivotal roles in the initiation of HCC in diverse biological processes like proliferation, metastasis, drug resistance, radio-resistance, energy metabolism, autophagy and so on. Besides, many of these lncRNAs are associated with clinicopathological features and clinical prognosis in HCC, which may provide a potential future application in the diagnosis and therapy of HCC.

Long noncoding RNA LINC01391 restrained gastric cancer aerobic glycolysis and tumorigenesis via targeting miR-12116/CMTM2 axis

Increasing studies indicate that long noncoding RNA (lncRNA) plays a critical role in aerobic glycolysis of various tumors. However, the contribution of lncRNA in gastric cancer (GC) cell glycolysis is still poorly understood. The objective of this research was to investigate the functional role and mechanism of lncRNA long intergenic non-protein coding RNA 1391 (LINC01391) in the aerobic glycolysis and tumorigenesis of GC. Here, we report that LINC01391 was low expressed in GC tissues and cell lines. LINC01391 overexpression hampered GC cell proliferation, migration, invasion and aerobic glycolysis, while LINC01391 knockdown demonstrated the opposite effects. LINC01391 overexpression delayed the tumor growth in vivo. Furthermore, LINC01391 interacted with miR-12116, and miR-12116 interacted with CMTM2 in GC cells. And miR-12116 and CMTM2 participated in the inhibitory effects of LINC01391 on cell migration, invasion and aerobic glycolysis in GC cells. LINC01391 restrained aerobic glycolysis and tumorigenesis of GC via targeting miR-12116/CMTM2 axis, which provides new insights into mechanism of GC progression.

Baicalein: A metabolite with promising antineoplastic activity

Cancer, being a multifactorial disease has diverse presentation in different subgroups which is mainly attributed to heterogenous presentation of tumor cells. This cancer cell heterogeneity is the major reason for variable response to standard chemotherapeutic regimes owing to which high relapse rate and multi-drug resistance has increasingly been reported over the past decade. Interestingly, the research on natural compounds in combination with standard therapies have reported with interesting and promising results from the pre-clinical trials and few of which have also been tested in other phases of clinical trials. This review focusses on baicalein, an emerging anti-cancerous natural compound, its chemistry and mechanism of action. In view of promising pre-clinical this review is mainly motivated by the results observed from baicalein treatment of different cancer cell population. With the advancing scientific evidence on the anti-malignant potential of baicalein with respect to its pharmacological activities encompassing from anti-inflammatory to anti-angiogenic/anti-metastatic effects, the focus is mainly directed to understanding the precise mechanism of action of baicalein. In the process of understanding the underlying signaling cascades, the role of mitogen activated protein kinase (MAPK), mammalian target of rapamycin (mTOR), AKT serine/threonine protein kinase B (AKT), poly(ADP-ribose) polymerase (PARP), matrix metalloproteinases-2 (MMP-2), matrix metalloproteinases-9 (MMP-9) and caspase-3/-8,-9 have been highlighted as the major players for baicalein anti-malignant potential. This is also supported by the interesting pre-clinical findings which cumulatively pave the way ahead for development of baicalein as an adjunct anti-cancer treatment with chemotherapeutic agents.

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

Molecular signaling pathways involved in cancer have been intensively studied due to their crucial role in cancer cell growth and dissemination. Among them, zinc finger E-box binding homeobox-1 (ZEB1) and -2 (ZEB2) are molecules that play vital roles in signaling pathways to ensure the survival of tumor cells, particularly through enhancing cell proliferation, promoting cell migration and invasion, and triggering drug resistance. Importantly, ZEB proteins are regulated by microRNAs (miRs). In this review, we demonstrate the impact that miRs have on cancer therapy, through their targeting of ZEB proteins. MiRs are able to act as onco-suppressor factors and inhibit the malignancy of tumor cells through ZEB1/2 down-regulation. This can lead to an inhibition of epithelial-mesenchymal transition (EMT) mechanism, therefore reducing metastasis. Additionally, miRs are able to inhibit ZEB1/2-mediated drug resistance and immunosuppression. Additionally, we explore the upstream modulators of miRs such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as these regulators can influence the inhibitory effect of miRs on ZEB proteins and cancer progression.

lncRNA TMPO-AS1 Exerts Oncogenic Roles in HCC Through Regulating miR-320a/SERBP1 Axis

Background

Previous evidence have shown that long non-coding RNA (lncRNA) TMPO antisense RNA 1 (TMPO-AS1) is involved in the aggressiveness of several cancers. Nevertheless, the precise functions of TMOP-AS1 in hepatocellular carcinoma (HCC) are still unresolved.

Materials and Methods

The expressions of TMPO-AS1 and miR-320a were detected in HCC tissues and cells by qRT-RCR. The cell growth, migration and invasion were detected by colony formation, wound healing assay and Transwell assay, respectively. The targeting relation between miR-320a and TMPO-AS1 was predicted by bioinformatics analysis and identified by luciferase reporter gene as well as FISH assay. The expression of SERPINE1 MRNA Binding Protein 1 (SERBP1) was detected by Western blot. The growth of HCC cell was analyzed using transplanted tumor model.

Results

Currently, we revealed that TMPO-AS1 was overexpressed in clinical HCC samples and a panel of HCC cell lines. Clinically, a higher level of TMPO-AS1 was connected to the advanced stage of HCC and worse prognosis of patients. Depletion of TMPO-AS1 repressed HCC cell viability, migration ability and invasiveness. Nevertheless, upregulation of TMPO-AS1 caused opposite results. Further studies revealed that lncRNA TMPO-AS1 was largely located in the cytoplasm of HCC cell and sponge miR-320a, resulting in increasing the level of SERBP1 in HCC cell. Finally, TMPO-AS1 silencing suppressed tumor growth of HCC cell in vivo.

Conclusion

Collectively, our results suggested that TMPO-AS1 was a promoting factor for the aggressive behaviors of HCC cell.

Mechanistic Involvement of Long Non-Coding RNAs in Oncotherapeutics Resistance in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is one of the most lethal forms of breast cancer (BC), with a significant disease burden worldwide. Chemoresistance and lack of targeted therapeutics are major hindrances to effective treatments in the clinic and are crucial causes of a worse prognosis and high rate of relapse/recurrence in patients diagnosed with TNBC. In the last decade, long non-coding RNAs (lncRNAs) have been found to perform a pivotal role in most cellular functions. The aberrant functional expression of lncRNAs plays an ever-increasing role in the progression of diverse malignancies, including TNBC. Therefore, lncRNAs have been recently studied as predictors and modifiers of chemoresistance. Our review discusses the potential involvement of lncRNAs in drug-resistant mechanisms commonly found in TNBC and highlights various therapeutic strategies to target lncRNAs in this malignancy.

MicroRNAs in cancer therapy: Their involvement in oxaliplatin sensitivity/resistance of cancer cells with a focus on colorectal cancer

The resistance of cancer cells into chemotherapy has restricted the efficiency of anti-tumor drugs. Oxaliplatin (OX) being an anti-tumor agent/drug is extensively used in the treatment of various cancer diseases. However, its frequent application has led to chemoresistance. As a consequence, studies have focused in finding underlying molecular pathways involved in OX resistance. MicroRNAs (miRs) are short endogenous non-coding RNAs that are able to regulate vital biological mechanisms such as cell proliferation and cell growth. The abnormal expression of miRs occurs in pathological events, particularly cancer. In the present review, we describe the involvement of miRs in OX resistance and sensitivity. The miRs are able to induce the oncogene factors and mechanisms, resulting in stimulation OX chemoresistance. Also, onco-suppressor miRs can enhance the sensitivity of cancer cells into OX chemotherapy and trigger apoptosis and cell cycle arrest, leading to reduced viability and progression of cancer cells. MiRs can also enhance the efficacy of OX chemotherapy. It is worth mentioning that miRs affect various down-stream targets in OX resistance/sensitivity such as STAT3, TGF-β, ATG4B, FOXO1, LATS2, NF-κB and so on. By identification of these miRs and their upstream and down-stream mediators, further studies can focus on targeting them to sensitize cancer cells into OX chemotherapy and induce apoptotic cell death.

Versatile role of curcumin and its derivatives in lung cancer therapy

Lung cancer is a main cause of death all over the world with a high incidence rate. Metastasis into neighboring and distant tissues as well as resistance of cancer cells to chemotherapy demand novel strategies in lung cancer therapy. Curcumin is a naturally occurring nutraceutical compound derived from Curcuma longa (turmeric) that has great pharmacological effects, such as anti-inflammatory, neuroprotective, and antidiabetic. The excellent antitumor activity of curcumin has led to its extensive application in the treatment of various cancers. In the present review, we describe the antitumor activity of curcumin against lung cancer. Curcumin affects different molecular pathways such as vascular endothelial growth factors, nuclear factor-κB (NF-κB), mammalian target of rapamycin, PI3/Akt, microRNAs, and long noncoding RNAs in treatment of lung cancer. Curcumin also can induce autophagy, apoptosis, and cell cycle arrest to reduce the viability and proliferation of lung cancer cells. Notably, curcumin supplementation sensitizes cancer cells to chemotherapy and enhances chemotherapy-mediated apoptosis. Curcumin can elevate the efficacy of radiotherapy in lung cancer therapy by targeting various signaling pathways, such as epidermal growth factor receptor and NF-κB. Curcumin-loaded nanocarriers enhance the bioavailability, cellular uptake, and antitumor activity of curcumin. The aforementioned effects are comprehensively discussed in the current review to further direct studies for applying curcumin in lung cancer therapy.

Targeting AKT/mTOR in Oral Cancer: Mechanisms and Advances in Clinical Trials

Oral cancer (OC) is a devastating disease that takes the lives of lots of people globally every year. The current spectrum of treatment modalities does not meet the needs of the patients. The disease heterogeneity demands personalized medicine or targeted therapies. Therefore, there is an urgent need to identify potential targets for the treatment of OC. Abundant evidence has suggested that the components of the protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway are intrinsic factors for carcinogenesis. The AKT protein is central to the proliferation and survival of normal and cancer cells, and its downstream protein, mTOR, also plays an indispensable role in the cellular processes. The wide involvement of the AKT/mTOR pathway has been noted in oral squamous cell carcinoma (OSCC). This axis significantly regulates the various hallmarks of cancer, like proliferation, survival, angiogenesis, invasion, metastasis, autophagy, and epithelial-to-mesenchymal transition (EMT). Activated AKT/mTOR signaling is also associated with circadian signaling, chemoresistance and radio-resistance in OC cells. Several miRNAs, circRNAs and lncRNAs also modulate this pathway. The association of this axis with the process of tumorigenesis has culminated in the identification of its specific inhibitors for the prevention and treatment of OC. In this review, we discussed the significance of AKT/mTOR signaling in OC and its potential as a therapeutic target for the management of OC. This article also provided an update on several AKT/mTOR inhibitors that emerged as promising candidates for therapeutic interventions against OC/head and neck cancer (HNC) in clinical studies.

An Overview of the Potential Antineoplastic Effects of Casticin

Cancer persists as one of the leading causes of deaths worldwide, contributing to approximately 9.6 million deaths per annum in recent years. Despite the numerous advancements in cancer treatment, there is still abundant scope to mitigate recurrence, adverse side effects and toxicities caused by existing pharmaceutical drugs. To achieve this, many phytochemicals from plants and natural products have been tested against cancer cell lines in vivo and in vitro. Likewise, casticin, a flavonoid extracted from the Vitex species, has been isolated from the leaves and seeds of V. trifolia and V. agnus-castus. Casticin possesses a wide range of therapeutic properties, including analgesic, anti-inflammatory, antiangiogenic, antiasthmatic and antineoplastic activities. Several studies have been conducted on the anticancer effects of casticin against cancers, including breast, bladder, oral, lung, leukemia and hepatocellular carcinomas. The compound inhibits invasion, migration and proliferation and induces apoptosis (casticin-induced, ROS-mediated and mitochondrial-dependent) and cell cycle arrest (G0/G1, G2/M, etc.) through different signaling pathways, namely the PI3K/Akt, NF-κB, STAT3 and FOXO3a/FoxM1 pathways. This review summarizes the chemo-preventive ability of casticin as an antineoplastic agent against several malignancies.

Potential therapeutic effects of curcumin mediated by JAK/STAT signaling pathway: A review

Curcumin is a naturally occurring nutraceutical compound with a number of therapeutic and biological activities such as antioxidant, anti-inflammatory, anti-diabetic, antitumor, and cardioprotective. This plant-derived chemical has demonstrated great potential in targeting various signaling pathways to exert its protective effects. Signal transducers and activator of transcription (STAT) is one of the molecular pathways involved in a variety of biological processes such as cell proliferation and cell apoptosis. Accumulating data demonstrates that the STAT pathway is an important target in treatment of a number of disorders, particularly cancer. Curcumin is capable of affecting STAT signaling pathway in induction of its therapeutic impacts. Curcumin is able to enhance the level of anti-inflammatory cytokines and improve inflammatory disorders such as colitis by targeting STAT signaling pathway. Furthermore, studies show that inhibition of JAK/STAT pathway by curcumin is involved in reduced migration and invasion of cancer cells. Curcumin normalizes the expression of JAK/STAT signaling pathway to exert anti-diabetic, renoprotective, and neuroprotective impacts. At the present review, we provide a comprehensive discussion about the effect of curcumin on JAK/STAT signaling pathway to direct further studies in this field.