The Underlying Mechanisms of Noncoding RNAs in the Chemoresistance of Hepatocellular Carcinoma

Noncoding RNAs and programmed cell death in hepatocellular carcinoma: Significant role of epigenetic modifications in prognosis, chemoresistance, and tumor recurrence rate

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with a high death rate in the world. The molecular mechanisms related to the pathogenesis of HCC have not been precisely defined so far. Hence, this review aimed to address the potential cross-talk between noncoding RNAs (ncRNAs) and programmed cell death in HCC. All related papers in the English language up to June 2023 were collected and screened. The searched keywords in scientific databases, including Scopus, PubMed, and Google Scholar, were HCC, ncRNAs, Epigenetic, Programmed cell death, Autophagy, Apoptosis, Ferroptosis, Chemoresistance, Tumor recurrence, Prognosis, and Prediction. According to the reports, ncRNAs, comprising long ncRNAs, microRNAs, circular RNAs, and small nucleolar RNAs can affect cell proliferation, migration, invasion, and metastasis, as well as cell death-related processes, such as autophagy, ferroptosis, necroptosis, and apoptosis in HCC by regulating cancer-associated genes and signaling pathways, for example, phosphoinositide 3-kinase/Akt, extracellular signal-regulated kinase/MAPK, and Wnt/β-catenin signaling pathways. It seems that ncRNAs, as epigenetic regulators, can be utilized as biomarkers in diagnosis, prognosis, survival and recurrence rates prediction, chemoresistance, and evaluation of therapeutic response in HCC patients. However, more scientific evidence is suggested to be accomplished to confirm these results.

Investigating autophagy and intricate cellular mechanisms in hepatocellular carcinoma: Emphasis on cell death mechanism crosstalk

Hepatocellular carcinoma (HCC) stands as a formidable global health challenge due to its prevalence, marked by high mortality and morbidity rates. This cancer type exhibits a multifaceted etiology, prominently linked to viral infections, non-alcoholic fatty liver disease, and genomic mutations. The inherent heterogeneity of HCC, coupled with its proclivity for developing drug resistance, presents formidable obstacles to effective therapeutic interventions. Autophagy, a fundamental catabolic process, plays a pivotal role in maintaining cellular homeostasis, responding to stressors such as nutrient deprivation. In the context of HCC, tumor cells exploit autophagy, either augmenting or impeding its activity, thereby influencing tumorigenesis. This comprehensive review underscores the dualistic role of autophagy in HCC, acting as both a pro-survival and pro-death mechanism, impacting the trajectory of tumorigenesis. The anti-carcinogenic potential of autophagy is evident in its ability to enhance apoptosis and ferroptosis in HCC cells. Pertinently, dysregulated autophagy fosters drug resistance in the carcinogenic context. Both genomic and epigenetic factors can regulate autophagy in HCC progression. Recognizing the paramount importance of autophagy in HCC progression, this review introduces pharmacological compounds capable of modulating autophagy-either inducing or inhibiting it, as promising avenues in HCC therapy.

Identification of Key lncRNAs Associated with Immune Infiltration and Prognosis in Gastric Cancer

Long non-coding RNAs (lncRNAs), as promising novel biomarkers for cancer treatment and prognosis, can function as tumor suppressors and oncogenes in the occurrence and development of many types of cancer, including gastric cancer (GC). However, little is known about the complex regulatory system of lncRNAs in GC. In this study, we systematically analyzed lncRNA and miRNA transcriptomic profiles of GC based on bioinformatics methods and experimental validation. An lncRNA-miRNA interaction network related to GC was constructed, and the nine crucial lncRNAs were identified. These 9 lncRNAs were found to be associated with the prognosis of GC patients by Cox proportional hazards regression analysis. Among them, the expression of lncRNA SNHG14 can affect the survival of GC patients as a potential prognostic marker. Moreover, it was shown that SNHG14 was involved in immune-related pathways and significantly correlated with immune cell infiltration in GC. Meanwhile, we found that SNHG14 affected immune function in many cancers, such as breast cancer and esophageal carcinoma. Such information revealed that SNHG14 may serve as a potential target for cancer immunotherapy. As well, our study could provide practical and theoretical guiding significance for clinical application of non-coding RNAs.

CircPHKB decreases the sensitivity of liver cancer cells to sorafenib via miR-1234-3p/CYP2W1 axis

Sorafenib is currently the first-line treatment for patients with advanced liver cancer, but its therapeutic efficacy declines significantly after a few months of treatment. Therefore, it is of great importance to investigate the regulatory mechanisms of sorafenib sensitivity in liver cancer cells. In this study, we provided initial evidence demonstrating that circPHKB, a novel circRNA markedly overexpressed in sorafenib-treated liver cancer cells, attenuated the sensitivity of liver cancer cells to sorafenib. Mechanically, circPHKB sequestered miR-1234-3p, resulting in the up-regulation of cytochrome P450 family 2 subfamily W member 1 (CYP2W1), thereby reducing the killing effect of sorafenib on liver cancer cells. Moreover, knockdown of circPHKB sensitized liver cancer cells to sorafenib in vivo. The findings reveal a novel circPHKB/miR-1234-3p/CYP2W1 pathway that decreases the sensitivity of liver cancer cells to sorafenib, suggesting that circPHKB and the axis may serve as promising targets to improve the therapeutic efficacy of sorafenib against liver cancer.

Recent progress and the emerging role of lncRNAs in cancer drug resistance; focusing on signaling pathways

It is becoming more and more apparent that many of the genetic alterations associated with cancer are located in areas that do not encode proteins. lncRNAs are a class of RNAs that do not code for proteins but play a crucial role in maintaining cell function and regulating various cellular processes. By doing this, they have recently introduced what may be a brand-new and essential layer of biological control. These have more than 200 nucleotides and are linked to several diseases; as a result, they have become potential tools for therapeutic intervention. Emerging technologies suggest the presence of mutations on genomic loci that give rise to lncRNAs rather than proteins in a disease as complex as cancer. These lncRNAs play essential parts in gene regulation, which impacts several cellular homeostasis processes, including proliferation, survival, migration, and genomic stability. The leading cause of death in the world today is cancer. Delays in diagnosis and a lack of standard and efficient treatments are the leading causes of the high death rate. Clinically, surgery is frequently used successfully to remove cancers that have not spread, but it is less successful in treating metastatic cancer, which has a drastically lower chance of survival. Chemotherapeutic drugs are a typical therapy to treat the cancer that has spread to other organs. Drug resistance to chemotherapy, however, presents a significant challenge to achieving positive outcomes and is frequently the cause of treatment failure. A substantial barrier to progress in medical oncology is cancer drug resistance. Resistance can develop clinically either before or after cancer treatment. According to this study, lncRNAs influence drug resistance through several different methods. LncRNAs often impact drug resistance by controlling the expression of a few intermediary regulatory variables rather than by directly affecting drug resistance. Additionally, lncRNAs have a variety of roles in cancer medication resistance. Most lncRNAs induce drug resistance when overexpressed; however, other lncRNAs have inhibitory effects. This study provides an overview of the current understanding of lncRNAs, relevance to cancer, and potential therapeutic applications.

Lnc-SNHG5 Promoted Hepatocellular Carcinoma Progression Through the RPS3-NFκB Pathway

Background

We planned to explore the underlying mechanism and clinical significance of lnc-SNHG5 and RPS3 in hepatocellular carcinoma in this current study.

Methods

The expression of Lnc-SNHG5 and RPS3 in HCC tissues and several cell lines were affirmed, respectively, using UALCAN, TIMER, TCGA and RT-qPCR assay. Cell proliferation ability was detected by colony formation assay and CCK8 assay. Cell apoptosis was monitored by flow cytometry assay. Next, the RPS3 expression levels and the related proteins in NFκB pathway were examined using Western blot analysis. The role of lnc-SNHG5 and RPS3 in vivo was identified by subcutaneous tumor bearing experiment.

Results

Lnc-SNHG5 was significantly increased in hepatocellular carcinoma tissues and in hepatocellular carcinoma cells. Further investigation showed that up-regulated lnc-SNHG5 promoted cell viability and cell proliferation ability of SMMC-7721 cells by regulating the cell apoptosis, while down-regulation of lnc-SNHG5 revealed opposite results in QGY-7703 cells. In terms of mechanism, we found that lnc-SNHG5 interacted with RPS3. Lnc-SNHG5 regulated the NFκB pathway through RPS3 in vitro and in vivo.

Conclusion

This study suggested that lnc-SNHG5 expression was signally up-regulated in hepatocellular carcinoma, and lnc-SNHG5 promoted the malignant phenotypes in vitro and in vivo via directly regulating RPS3-NFκB pathway. Lnc-SNHG5 might be a target for molecular targeted therapy, a potential and novel diagnostic marker for HCC patients.

cDCBLD2 mediates sorafenib resistance in hepatocellular carcinoma by sponging miR-345-5p binding to the TOP2A coding sequence

Sorafenib is a first-line chemotherapy drug for treating advanced hepatocellular carcinoma (HCC). However, its therapeutic effect has been seriously affected by the emergence of sorafenib resistance in HCC patients. The underlying mechanism of sorafenib resistance is unclear. Here, we report a circular RNA, cDCBLD2, which plays an important role in sorafenib resistance in HCC. We found that cDCBLD2 was upregulated in sorafenib-resistant (SR) HCC cells, and knocking down cDCBLD2 expression could significantly increase sorafenib-related cytotoxicity. Further evidence showed that cDCBLD2 can bind to microRNA (miR)-345-5p through a competing endogenous RNA mechanism, increase type IIA topoisomerase (TOP2A) mRNA stability through a miRNA sponge mechanism, and reduce the effects of sorafenib treatment on HCC by inhibiting apoptosis. Our findings also suggest that miR-345-5p can negatively regulate TOP2A levels by binding to the coding sequence region of its mRNA. Additionally, targeting cDCBLD2 by injecting a specific small interfering RNA (siRNA) could significantly overcome sorafenib resistance in a patient-derived xenograft (PDX) mouse model of HCC. Taken together, our study provides a proof-of-concept for a potential strategy to overcome sorafenib resistance in HCC patients by targeting cDCBLD2 or TOP2A.

Linc-ROR drive adriamycin resistance by targeting AP-2α/Wnt/β-catenin axis in hepatocellular carcinoma

Adriamycin is widely used as a chemotherapeutic strategy for advanced hepatocellular carcinoma (HCC). However, the clinical response was disappointing because of the acquired drug resistance with long-term usage. Revealing the underlying mechanism could provide promising therapeutics for the drug-resistant patients. The recently identified linc-ROR (long intergenic non-protein-coding RNA, regulator of reprogramming) has been found to be an oncogene in various cancers, and it also demonstrated to mediate drug resistance and metastasis. We thereby wonder whether this lincRNA could mediate adriamycin chemoresistance in HCC. In this study, linc-ROR was found to be upregulated in adriamycin-resistant HCC cells. And its overexpression accelerated epithelial-mesenchymal transition (EMT) program and adriamycin resistance. Conversely, its silence suppressed EMT and made HCC cells sensitize to adriamycin in vitro and in vivo. Further investigation revealed that linc-ROR physically interacted with AP-2α, mediated its stability by a post-translational modification manner, and sequentially activated Wnt/β-catenin pathway. Furthermore, linc-ROR expression was positively associated with β-catenin expression in human clinical specimens. Taken together, linc-ROR promoted tumorigenesis and adriamycin resistance in HCC via a linc-ROR/AP-2α/Wnt/β-catenin axis, which could be developed as a potential therapeutic target for the adriamycin-resistant patients.

Lnc-ZEB2-19 Inhibits the Progression and Lenvatinib Resistance of Hepatocellular Carcinoma by Attenuating the NF-κB Signaling Pathway through the TRA2A/RSPH14 Axis

Long non-coding RNAs have been reported to play a crucial role in tumor progression in hepatocellular carcinoma (HCC). Lnc-ZEB2-19 has been validated to be deficiently expressed in HCC. However, the capabilities and underlying mechanisms of lnc-ZEB2-19 remain uncertain. In this study, we verified that the downregulation of lnc-ZEB2-19 was prevalent in HCC and significantly correlated with the unfavorable prognosis. Further in vitro and in vivo verified that lnc-ZEB2-19 notably inhibited the proliferation, metastasis, stemness, and lenvatinib resistance (LR) of HCC cells. Mechanistically, lnc-ZEB2-19 inhibited HCC progression and LR by specifically binding to transformer 2α (TRA2A) and promoting its degradation, which resulted in the instability of RSPH14 mRNA, leading to the downregulation of Rela(p65) and p-Rela(p-p65). Furthermore, rescue assays showed that silencing RSPH14 partially restrained the effect of knockdown expression of lnc-ZEB2-19 on HCC cell metastatic ability and stemness. The findings describe a novel regulatory axis, lnc-ZEB2-19/TRA2A/RSPH14, downregulating the nuclear factor kappa B to inhibit HCC progression and LR.

Hypoxia-induced lncRNA MRVI1-AS1 accelerates hepatocellular carcinoma progression by recruiting RNA-binding protein CELF2 to stabilize SKA1 mRNA

BACKGROUND

Long non-coding RNAs (lncRNAs) perform a vital role during the progression of hepatocellular carcinoma (HCC). Here, we aimed to identify a novel lncRNA involved in HCC development and elucidate the underlying molecular mechanism.

METHODS

The RT-qPCR and TCGA dataset analysis were applied to explore the expressions of MRVI1-AS1 in HCC tissues and cell lines. Statistical analysis was applied to analyze the clinical significance of MRVI1-AS1 in HCC. The functions of MRVI1-AS1 in HCC cells metastasis and growth were explored by transwell assays, wound healing assay, MTT assay, EdU assay, the intravenous transplantation tumor model, and the subcutaneous xenograft tumor model. Microarray mRNA expression analysis, dual luciferase assays, and actinomycin D treatment were used to explore the downstream target of MRVI1-AS1 in HCC cells. RIP assay was applied to assess the direct interactions between CELF2 and MRVI1-AS1 or SKA1 mRNA. Rescue experiments were employed to validate the functional effects of MRVI1-AS1, CELF2, and SKA1 on HCC cells.

RESULTS

MRVI1-AS1 was found to be dramatically upregulated in HCC and the expression was strongly linked to tumor size, venous infiltration, TNM stage, as well as HCC patients' outcome. Cytological experiments and animal experiments showed that MRVI1-AS1 promoted HCC cells metastasis and growth. Furthermore, SKA1 was identified as the downstream targeted mRNA of MRVI1-AS1 in HCC cells, and MRVI1-AS1 increased SKA1 expression by recruiting CELF2 protein to stabilize SKA1 mRNA. In addition, we found that MRVI1-AS1 expression was stimulated by hypoxia through a HIF-1-dependent manner, which meant that MRVI1-AS was a direct downstream target gene of HIF-1 in HCC.

CONCLUSION

In a word, our findings elucidated that hypoxia-induced MRVI1-AS1 promotes metastasis and growth of HCC cells via recruiting CELF2 protein to stabilize SKA1 mRNA, pointing to MRVI1-AS1 as a promising clinical application target for HCC therapy.

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

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

KDM5B regulates the PTEN/PI3K/Akt pathway to increase sorafenib-resistance in hepatocellular carcinoma

Lysine-specific demethylase 5B (KDM5B) exerts its tumor-promoting functions in numerous malignancies, although the possible mechanisms by which KDM5B promotes cancer aggressiveness in hepatocellular carcinoma (HCC) have been preliminarily explored, the role of this gene in regulating sorafenib-resistance in HCC has not been studied. Thus, the present study was designed to resolve this problem, and our data suggested that KDM5B was significantly upregulated in the HCC tissues collected from patients with sorafenib treatment history. Consistently, continuous low-dose sorafenib administration increased KDM5B expression levels in the sorafenib-resistant HCC cells compared to their sorafenib-sensitive counterparts. Next, by performing the functional experiments, we found that KDM5B positively regulated sorafenib-resistance and cancer stem cell (CSC) properties in HCC cells in vitro and in vivo. Furthermore, upregulation of KDM5B-degraded phosphatase and tensin homolog (PTEN), results in the activation of the downstream oncogenic PI3K/Akt pathway. Subsequently, the rescuing experiments verified that the promoting effects of KDM5B overexpression on chemoresistance and cancer stemness in HCC cells were all abrogated by PI3K (p110) knockdown and PTEN overexpression. Collectively, those data hinted that KDM5B influenced CSC properties and sorafenib-resistance in HCC cells through modulating the PTEN/PI3K/Akt pathway, and KDM5B could be used as a potential target for the treatment of HCC in clinic.

Long non-coding RNAs (lncRNAs); roles in tumorigenesis and potentials as biomarkers in cancer diagnosis

New research has indicated that long non-coding RNAs (lncRNAs) play critical roles in a broad range of biological processes, including the pathogenesis of many complex human diseases, including cancer. The detailed regulation mechanisms of many lncRNAs in cancer initiation and progression have yet to be discovered, even though a few of lncRNAs' functions in cancer have been characterized. In the present study, we summarize recent advances in the mechanisms and functions of lncRNAs in cancer. We focused on the roles of newly-identified lncRNAs as oncogenes and tumor suppressors, as well as the potential pathways these molecules could play. The paper also discusses their potential uses as biomarkers for the diagnosis and prognosis of cancer.

miRNAs inspirations in hepatocellular carcinoma: Detrimental and favorable aspects of key performers

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related deaths worldwide. HCC initiation, progression, and therapy failure are all influenced by various variables, including microRNAs (miRNAs). miRNAs are short non-coding RNA sequences that modulate target mRNA expression by deteriorating or repressing translation. miRNAs play an imperative role in HCC pathogenesis by triggering the induction of cancer stem cells (CSCs) and their proliferation, while also delaying apoptosis, sustaining the cell cycle, and inspiring angiogenesis, invasion, and metastasis. Additionally, miRNAs modulate crucial HCC-related molecular pathways such as the p53 pathway, the Wnt/β-catenin pathway, VEGFR2, and PTEN/PI3K/AKT pathway. Consequently, the goal of this review was to give an up-to-date overview of oncogenic and tumor suppressor (TS) miRNAs, as well as their potential significance in HCC pathogenesis and treatment responses, highlighting their underpinning molecular pathways in HCC initiation and progression. Similarly, the biological importance and clinical application of miRNAs in HCC are summarized.

Novel lncRNA AL033381.2 Promotes Hepatocellular Carcinoma Progression by Upregulating PRKRA Expression

Hepatocellular carcinoma (HCC) is a common malignant tumor that is characterized by aggressiveness and poor prognosis. Accumulating evidence indicates that oxidative stress plays a crucial role in carcinogenesis, whereas the potential mechanism between oxidative stress and carcinogenic effects remains elusive. In recent years, long noncoding RNAs (lncRNAs) in cancers have attracted extensive attention and have been shown to be involved in oxidative stress response and carcinogenesis. Nevertheless, the roles of lncRNA AL033381.2 in regulating the development and progression of HCC still remain unclear. The purpose of our study was to evaluate the potential effects and molecular mechanisms of AL033381.2 that may be involved in oxidative stress response in HCC. Using bioinformatics analyses based on the TCGA database, we screened and identified a novel lncRNA AL033381.2 in HCC, which may be involved in oxidative stress responses. qRT-PCR analysis revealed that AL033381.2 is upregulated in HCC tissues. Through in vitro and in vivo experiments, we found that AL033381.2 dramatically facilitates the growth and metastasis of HCC. Mechanistically, RNA pull-down experiments, mass spectrometry, PathArray™, and RIP were used to determine that AL033381.2 binds to PRKRA and may be involved in AL033381.2-mediated oncogenic functions in HCC cells. Moreover, rescue experiments demonstrated that PRKRA overexpression rescues the abilities of HCC cell proliferation, migration, and invasion that were affected by AL033381.2 knockdown. Furthermore, we produced a nanoparticle-based siRNA delivery system and tested its therapeutic effects in vivo. The results showed that the in vivo growth rate of the tumors treated with the nanoparticle/AL033381.2 siRNA complexes was dramatically lower than those treated with the nanoparticle/scramble siRNA complexes. Taken together, our results suggest that the novel lncRNA AL033381.2 may be involved in oxidative stress response by targeting oxidative stress-related genes in HCC. AL033381.2 plays vital oncogenic roles in HCC progression and may be a novel therapeutic marker for HCC diagnosis and treatment.

Treatment with b-AP15 to Inhibit UCHL5 and USP14 Deubiquitinating Activity and Enhance p27 and Cyclin E1 for Tumors with p53 Deficiency

Background: TP53 protein is lost or mutated in about half of all types of human cancers and small molecules to regulate mutant p53 repair, or interrupt ubiquitination degradation of p53 induced by E3-ubiquitin ligase Mdm2 have a potential application in clinical application. Methods: To inhibit the deubiquitinase activity of 19S proteasome and restore the p53 protein level, in this study, we utilized p53 knockout mice to test the anti-cancer effect of a specific USP14 and UCH37 inhibitor b-AP15. Results: Our results show that UCHL5, USP14 and COPS5 are upregulated in p53-related tumors, and higher expression of these genes results in a shorter overall survival in patients with p53 deficiency. Treatment with b-AP15, a UCHL5 and USP14 deubiquitinating activity inhibitor in 19S regulatory subunit, induces tumor regression and prolong the survival period of tumor-loaded mice through down-regulation of COPS5 and its downstream AP-1 and E2F1, and up-regulation of the cell cycle-related proteins p27 and Cyclin E1. Conclusions: Thus, our results suggested that inhibition of UCHL5 and USP14 deubiquitinating activity in 19S proteasome may contribute an extensive approach to preventing tumor progress due to p53 deficiency.

The potential role of miR-1290 in cancer progression, diagnosis, prognosis, and treatment: An oncomiR or onco-suppressor microRNA?

Cancer is one of the leading causes of death in humans because of the lack of early diagnosis, distant metastases, and the resistance to adjuvant therapies, including chemotherapy and radiotherapy. In addition to playing an essential role in tumor progression and development, microRNAs (miRNAs) can be used as a robust biomarker in the early detection of cancer. MiR-1290 was discovered for the first time in human embryonic stem cells, and under typical physiological situations, plays an essential role in neuronal differentiation and neural stem cell proliferation. Its coding sequence is located at the 1p36.13 regions in the first intron of the aldehyde dehydrogenase 4 gene member A1. miR-1290 is out of control in many cancers such as breast cancer, colorectal cancer, esophageal squamous cell carcinoma, gastric cancer, lung cancer, pancreatic cancer, and plays a vital role in their development. Therefore, it is suggested that miR-1290 can be considered as a potential diagnostic and therapeutic target in many cancers. In addition to the importance of miR-1290 in the noninvasive diagnosis of various cancers, this systematic review study discussed the role of miR-1290 in altering the expression of different genes involved in cancer development and chemo-radiation resistance. Moreover, it considered the regulatory effect of natural products on miR-1290 expression and the interaction of lncRNAs by miR-1290.

Methyltransferase-Like 3-Mediated m6A Methylation of Hsa_circ_0058493 Accelerates Hepatocellular Carcinoma Progression by Binding to YTH Domain-Containing Protein 1

Circular RNAs (circRNAs) are highly correlated with the progression and prognosis of hepatocellular carcinoma (HCC). In addition, mounting evidence has revealed that N6-methyladenosine (m6A) methylation, a common RNA modification, is involved in the progression of malignancies. In this research, a novel circRNA, hsa_circ_0058493, was proven to be upregulated in HCC, which was correlated with the prognosis of HCC patients. Experimentally, hsa_circ_0058493 knockdown suppressed the growth and metastasis of HCC cells in vivo and in vitro. On the contrary, the overexpression of hsa_circ_0058493 in HCC cells had the opposite effect in vitro. Mechanistic experiments revealed that hsa_circ_0058493 contained m6A methylation sites and that methyltransferase-like 3 (METTL3) mediated the degree of methylation modification of hsa_circ_0058493. Furthermore, YTH domain-containing protein 1 (YTHDC1) could bind to hsa_circ_0058493 and promote its intracellular localization from the nucleus to the cytoplasm. In addition, both si-METTL3 and si-YTHDC1 suppressed HCC cell growth and metastasis, whereas rescue experiments confirmed that overexpression of hsa_circ_0058493 inverted the inhibitory effects of si-METTL3 and si-YTHDC1 on HCC cells. Taken together, this study explored the oncogenic role of m6A-modified hsa_circ_0058493 and found to accelerate HCC progression via the METTL3-hsa_circ_0058493-YTHDC1 axis, indicating a potential therapeutic target for this deadly disease.

Evaluating the Effect of Lenvatinib on Sorafenib-Resistant Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is one of the major causes of cancer-related deaths worldwide. Sorafenib has been used as a first-line systemic treatment for over a decade. However, resistance to sorafenib limits patient response and presents a major hurdle during HCC treatment. Lenvatinib has been approved as a first-line systemic treatment for advanced HCC and is the first agent to achieve non-inferiority against sorafenib. Therefore, in the present study, we evaluated the inhibition efficacy of lenvatinib in sorafenib-resistant HCC cells. Only a few studies have been conducted on this topic. Two human HCC cell lines, Huh-7 and Hep-3B, were used to establish sorafenib resistance, and in vitro and in vivo studies were employed. Lenvatinib suppressed sorafenib-resistant HCC cell proliferation mainly by inducing G1 cell cycle arrest through ERK signaling. Hep-3B sorafenib-resistant cells showed partial cross-resistance to lenvatinib, possibly due to the contribution of poor autophagic responsiveness. Overall, the findings suggest that the underlying mechanism of lenvatinib in overcoming sorafenib resistance in HCC involves FGFR4-ERK signaling. Lenvatinib may be a suitable second-line therapy for unresectable HCC patients who have developed sorafenib resistance and express FGFR4.

N6-methyladenosine (m6A)-mediated lncRNA DLGAP1-AS1enhances breast canceradriamycin resistance through miR-299-3p/WTAP feedback loop

Chemotherapy resistance is identified as an obstacle for breast cancer (BC) therapy, and, besides, increasing evidence indicates that long-noncoding RNAs (lncRNAs) participate in the regulation of BC adriamycin (ADR) resistance. Here, our work shows that lncRNA DLGAP1 antisense RNA 1 (DLGAP1-AS1) is up-regulated in ADR-resistant BC cells (MCF-7/ADR). Clinically, higher DLGAP1-AS1 expression was closely correlated to poorer clinical prognosis. Results showed that DLGAP1-AS1 promoted the ADR IC50 and proliferation of ADR-resistant cells. Moreover, N6-methyladenosine (m6A) methyltransferase WT1 associated protein (WTAP) binds to the m6A modified site of DLGAP1-AS1 and motivates its stability. Mechanistically, DLGAP1-AS1 sponged miR-299-3p through 3'-untranslated region (3'-UTR) binding, which in turn relieved the repression of WTAP and thus upregulated WTAP expression. In conclusion, above findings conclude that lncRNA DLGAP1-AS1 promotes BC ADR-resistance through WTAP/DLGAP1-AS1/miR-299-3p feedback loop.

A curcumin analog GL63 inhibits the malignant behaviors of hepatocellular carcinoma by inactivating the JAK2/STAT3 signaling pathway via the circular RNA zinc finger protein 83/microRNA-324-5p/cyclin-dependent kinase 16 axis

BACKGROUND AND AIM

(1E,4E)-1,5-bis(2-bromophenyl) penta-1,4-dien-3-one (GL63) is a curcumin analog that can protect against carcinogenesis in hepatocellular carcinoma (HCC). The aim of this study was to explore the molecular mechanism of GL63 in HCC.

METHODS

Cell viability was examined by cell counting kit-8 (CCK-8) assay. Circular RNA zinc finger protein 83 (circZNF83), microRNA-324-5p (miR-324-5p), and cyclin-dependent kinase 16 (CDK16) levels were measured via the quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was assessed using colony formation assay. Flow cytometry was performed for detecting cell cycle and apoptosis. Protein analysis was conducted by western blot. Cell migration and invasion were determined using transwell assay. Target relation was analyzed using dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The function of GL63 in vivo was researched by xenograft model in mice.

RESULTS

GL63 inhibited the circZNF83 expression in HCC cells. CircZNF83 overexpression attenuated the inhibitory effects of GL63 on HCC cell growth, cell cycle progression, migration, and invasion but the promoting effect on cell apoptosis. CircZNF83 served as a sponge of miR-324-5p and circZNF83/miR-324-5p axis was involved in the functional regulation of GL63 in HCC progression. Moreover, CDK16 was a downstream target of miR-324-5p and circZNF83 could regulate the CDK16 expression by sponging miR-324-5p. The anti-tumor function of GL63 was also related to the miR-324-5p/CDK16 axis. In addition, GL63 inactivated the JAK2/STAT3 pathway via downregulating circZNF83 to mediate the miR-324-5p/CDK16 axis. GL63 also repressed tumor growth in vivo through the circZNF83/miR-324-5p/CDK16-mediated JAK2/STAT3 signal inhibition.

CONCLUSION

This study suggested GL63 impeded the HCC development by blocking the JAK2/STAT3 signaling pathway via mediating the circZNF83/miR-324-5p/CDK16 axis.

LRGCPND: Predicting Associations between ncRNA and Drug Resistance via Linear Residual Graph Convolution

Accurate inference of the relationship between non-coding RNAs (ncRNAs) and drug resistance is essential for understanding the complicated mechanisms of drug actions and clinical treatment. Traditional biological experiments are time-consuming, laborious, and minor in scale. Although several databases provide relevant resources, computational method for predicting this type of association has not yet been developed. In this paper, we leverage the verified association data of ncRNA and drug resistance to construct a bipartite graph and then develop a linear residual graph convolution approach for predicting associations between non-coding RNA and drug resistance (LRGCPND) without introducing or defining additional data. LRGCPND first aggregates the potential features of neighboring nodes per graph convolutional layer. Next, we transform the information between layers through a linear function. Eventually, LRGCPND unites the embedding representations of each layer to complete the prediction. Results of comparison experiments demonstrate that LRGCPND has more reliable performance than seven other state-of-the-art approaches with an average AUC value of 0.8987. Case studies illustrate that LRGCPND is an effective tool for inferring the associations between ncRNA and drug resistance.

The power and the promise of circRNAs for cancer precision medicine with functional diagnostics and prognostic prediction

Circular RNA (circRNA) is a large class of covalently closed circular RNA. As a member of competitive endogenous RNA (ceRNA), it participates in the regulation of circRNA-miRNA-mRNA network and plays an important role in the regulation of physiology and pathology. CircRNA is produced by the reverse splicing of exon, intron or both, forming exon or intron circRNA. Studies have shown that circRNA is a ubiquitous molecule, which exceeds the linear mRNA distributed in human cells. Because of its covalent closed-loop structure, circRNA is resistant to RNase R, which is more stable than linear mRNA; circRNA is highly conserved in different species. It was found that circRNA competitively adsorbs miRNA, as a miRNA sponge, to involve in the expression regulation of a variety of genes and plays an important role in tumor development, invasion, metastasis and other processes. These molecules offer new potential opportunities for therapeutic intervention and serve as biomarkers for diagnosis. In this paper, the origin, characteristics and functions of circRNA and its role in tumor development, invasion and metastasis, diagnosis and prognosis are reviewed.

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.

PLEKHA8P1 Promotes Tumor Progression and Indicates Poor Prognosis of Liver Cancer

Hepatocellular carcinoma (HCC) records the second-lowest 5-year survival rate despite the avalanche of research into diagnosis and therapy. One of the major obstacles in treatment is chemoresistance to drugs such as 5-fluorouracil (5-FU), making identification and elucidation of chemoresistance regulators highly valuable. As the regulatory landscape grows to encompass non-coding genes such as long non-coding RNAs (lncRNAs), a relatively new class of lncRNA has emerged in the form of pseudogene-derived lncRNAs. Through bioinformatics analyses of the TCGA LIHC dataset, we have systematically identified pseudogenes of prognostic value. Initial experimental validation of selected pseudogene-derived lncRNA (PLEKHA8P1) and its parental gene (PLEKHA8), a well-studied transport protein in Golgi complex recently implicated as an oncogene in both colorectal and liver cancer, indicates that the pseudogene/parental gene pair promotes tumor progression and that their dysregulated expression levels affect 5-FU-induced chemoresistance in human HCC cell line FT3-7. Our study has thus confirmed cancer-related functions of PLEKHA8, and laid the groundwork for identification and validation of oncogenic pseudogene-derived lncRNA that shows potential as a novel therapeutic target in circumventing chemoresistance induced by 5-FU.

Circular RNA circUBE2D2 functions as an oncogenic factor in hepatocellular carcinoma sorafenib resistance and glycolysis

Circular RNAs (circRNAs) have been reported to regulate the hepatocellular carcinoma (HCC) chemoresistance and tumor progression by regulating gene expression. However, the underlying molecular mechanisms of HCC sorafenib resistance regulated by circRNAs remain unclear. Here, higher expression of circUBE2D2 was directly associated with low survival rate in HCC patients. Functional experiments showed that circUBE2D2 promoted the glycolysis (Warburg effect) and sorafenib resistance in vitro, and knockdown of circUBE2D2 repressed the tumor growth in vivo. Mechanistically, circUBE2D2 was predominantly localized in the cytoplasm and sponged miR-889-3p, which in turn targeted the 3'-UTR of LDHA mRNA. Therefore, circUBE2D2 exerted an oncogenic role through miR-889-3p/LDHA axis. In conclusion, these findings demonstrate that circUBE2D2 accelerated the HCC glycolysis and sorafenib resistance via circUBE2D2/miR-889-3p/LDHA axis, which provides a novel approach for HCC treatment.

Basic approaches, challenges and opportunities for the discovery of small molecule anti-tumor drugs

Chemotherapy is one of the main treatments for cancer, especially for advanced cancer patients. In the past decade, significant progress has been made with the research into the molecular mechanisms of cancer cells and the precision medicine. The treatment on cancer patients has gradually changed from cytotoxic chemotherapy to precise treatment strategy. Research into anticancer drugs has also changed from killing effects on all cells to targeting drugs for target genes. Besides, researchers have developed the understanding of the abnormal physiological function, related genomics, epigenetics, and proteomics of cancer cells with cancer genome sequencing, epigenetic research, and proteomic research. These technologies and related research have accelerated the development of related cancer drugs. In this review, we summarize the research progress of anticancer drugs, the current challenges, and future opportunities.

LINC00680 enhances hepatocellular carcinoma stemness behavior and chemoresistance by sponging miR-568 to upregulate AKT3

BACKGROUND

Hepatocellular carcinoma (HCC) has an extremely poor prognosis due to the development of chemoresistance, coupled with inherently increased stemness properties. Long non-coding RNAs (LncRNAs) are key regulators for tumor cell stemness and chemosensitivity. Currently the relevance between LINC00680 and tumor progression was still largely unknown, with only one study showing its significance in glioblastoma. The study herein was aimed at identifying the role of LINC00680 in the regulation HCC stemness and chemosensitivity.

METHODS

QRT-PCR was used to detect the expression of LINC00680, miR-568 and AKT3 in tissue specimen and cell lines. Gain- or loss-of function assays were applied to access the function of LINC00680 in HCC cells, including cell proliferation and stemness properties. HCC stemness and chemosensitivity were determined by sphere formation, cell viability and colony formation. Luciferase reporter, RNA immunoprecipitation (RIP), and RNA pull-down assays were performed to examine the interaction between LINC00680 and miR-568 as well as that between miR-568 and AKT3. A nude mouse xenograft model was established for the in vivo study.

RESULTS

We found that LINC00680 was remarkably upregulated in HCC tissues. Patients with high level of LINC00680 had poorer prognosis. LINC00680 overexpression significantly enhanced HCC cell stemness and decreased in vitro and in vivo chemosensitivity to 5-fluorouracil (5-Fu), whereas LINC00680 knockdown led to opposite results. Mechanism study revealed that LINC00680 regulated HCC stemness and chemosensitivity through sponging miR-568, thereby expediting the expression of AKT3, which further activated its downstream signaling molecules, including mTOR, elF4EBP1, and p70S6K.

CONCLUSION

LINC00680 promotes HCC stemness properties and decreases chemosensitivity through sponging miR-568 to activate AKT3, suggesting that LINC00680 might be a potentially important HCC diagnosis marker and therapeutic target.