The long non-coding RNA LncHDAC2 drives the self-renewal of liver cancer stem cells via activation of Hedgehog signaling

The Contribution of Autophagy and LncRNAs to MYC-Driven Gene Regulatory Networks in Cancers

MYC is a target of the Wnt signalling pathway and governs numerous cellular and developmental programmes hijacked in cancers. The amplification of MYC is a frequently occurring genetic alteration in cancer genomes, and this transcription factor is implicated in metabolic reprogramming, cell death, and angiogenesis in cancers. In this review, we analyse MYC gene networks in solid cancers. We investigate the interaction of MYC with long non-coding RNAs (lncRNAs). Furthermore, we investigate the role of MYC regulatory networks in inducing changes to cellular processes, including autophagy and mitophagy. Finally, we review the interaction and mutual regulation between MYC and lncRNAs, and autophagic processes and analyse these networks as unexplored areas of targeting and manipulation for therapeutic gain in MYC-driven malignancies.

The crosstalk network of XIST/miR-424-5p/OGT mediates RAF1 glycosylation and participates in the progression of liver cancer

BACKGROUND

Liver cancer is a major public health concern, but the mechanistic actions of biomarkers contributing to liver cancer remain to be determined. In this study, we aimed to investigate the regulatory cascade of microRNA-424-5p (miR-424-5p), X-inactive-specific transcript (XIST) and O-GlcNAc transferase (OGT) in liver cancer.

METHODS

Differentially expressed miRNAs and target genes related to liver cancer were predicted by bioinformatics analyses, and their expression was determined in liver tissues of patients with liver cancer and liver cancer cells. The RNA immunoprecipitation (RIP), RNA pull-down and dual luciferase reporter assay were used to examine the binding affinity among XIST and miR-424-5p and OGT. Then, gain- and loss-of-function assays were conducted to evaluate the effects of the XIST/miR-424-5p/OGT axis on malignant phenotypes. A nude mouse model of liver cancer was further established for in vivo substantiation.

RESULTS

XIST and OGT were up-regulated in liver cancer tissues and cells, responsible for poor prognosis in patients with liver cancer, while miR-424-5p was down-regulated. XIST competitively bound to miR-424-5p to increase OGT expression. XIST silencing inhibited malignant phenotypes of liver cancer cells, while miR-424-5p down-regulation negated its effect. miR-424-5p suppressed RAF1 glycosylation by negatively regulating OGT expression and promoted its ubiquitination/degradation. Furthermore, XIST knockdown inhibited tumour growth and metastasis in nude mice, while ectopic OGT reversed its effect.

CONCLUSION

These results reveal a novel mechanism by which the interaction of XIST/miR-424-5p/OGT participates in the malignancy and metastasis of liver cancer.

Identification of cis-HOX-HOXC10 axis as a therapeutic target for colorectal tumor-initiating cells without APC mutations

Colorectal cancer (CRC) is one of the most common cancers worldwide, in which adenomatous polyposis coli (APC) mutations are frequently and uniquely observed. Here we find that cis-HOX (circular RNA stabilizing HOXC10) is robustly expressed in colorectal tumor-initiating cells (TICs). cis-HOX knockout decreases colorectal TIC numbers and impairs the self-renewal, tumorigenesis, and metastatic capacities of TICs, whereas cis-HOX overexpression drives colorectal TIC self-renewal and metastasis. Mechanistically, cis-HOX binds to HOXC10 mRNA to attenuate its decay through blocking the K-homology splicing regulatory protein (KSRP)-binding sequence of HOXC10 3' UTR. HOXC10 is highly expressed in colorectal tumors and TICs and triggers Wnt/β-catenin activation by activating FZD3 expression. HOXC10 inhibitor salinomycin exerts efficient therapeutic effects in APC-wild-type colorectal tumors, but not in tumors with APC nonsense mutations. Therefore, the cis-HOX-HOXC10 pathway drives colorectal tumorigenesis, stemness, and metastasis and serves as a potential therapeutic target for APC-wild-type colorectal tumors.

Emerging Regulatory Mechanisms Involved in Liver Cancer Stem Cell Properties in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the predominant form of primary liver cancer and one of the leading causes of cancer-related deaths worldwide. A growing body of evidence supports the hypothesis that HCC is driven by a population of cells called liver cancer stem cells (LCSCs). LCSCs have been proposed to contribute to malignant HCC progression, including promoting tumor occurrence and growth, mediating tumor metastasis, and treatment resistance, but the regulatory mechanism of LCSCs in HCC remains unclear. Understanding the signaling pathways responsible for LCSC maintenance and survival may provide opportunities to improve patient outcomes. Here, we review the current literature about the origin of LCSCs and the niche composition, describe the current evidence of signaling pathways that mediate LCSC stemness, then highlight several mechanisms that modulate LCSC properties in HCC progression, and finally, summarize the new developments in therapeutic strategies targeting LCSCs markers and regulatory pathways.

Comprehensive analysis of an immune-related ceRNA network in identifying a novel lncRNA signature as a prognostic biomarker for hepatocellular carcinoma

The function of competitive endogenous RNA (ceRNA) network in the immune regulation of hepatocellular carcinoma (HCC) is unclear. Our study aimed to construct an immune-related ceRNA network and develop an immune-related long noncoding RNA (lncRNA) signature to assess the prognosis of HCC patients and to optimize the treatment methods. We firstly constructed a ceRNA regulatory network for HCC using differentially expressed lncRNAs, mRNAs and microRNAs (miRNAs) from the Cancer Genome Atlas. A signature was constructed by 11 immune-related prognostic lncRNAs from the ceRNA network. The survival analysis and receiver operating characteristic analysis validated the reliability of the signature. Multivariate Cox regression analysis revealed that the signature could act an independent prognostic indicator. This signature also showed high association with immune cell infiltration and immune check blockades. LINC00491 was identified as the hub lncRNA in the signature. In vitro and in vivo evidence demonstrated that silencing of LINC00491 significantly inhibited HCC growth. Finally, 59 lncRNAs, 21 miRNAs, and 26 mRNAs were obtained to build the immune-related ceRNA network for HCC. In conclusion, our novel immune-related lncRNA prognostic signature and the immune-related ceRNA network might provide in-depth insights into tumor-immune interaction of HCC and promote better individual treatment strategies in HCC patients.

Tumor-derived exosomal BCYRN1 activates WNT5A/VEGF-C/VEGFR3 feedforward loop to drive lymphatic metastasis of bladder cancer

BACKGROUND

Patients with lymph node (LN) metastatic bladder cancer (BCa) present with extremely poor prognosis. BCa-derived exosomes function as crucial bioactive cargo carriers to mediate the signal transduction in tumor microenvironment triggering tumor metastasis. However, the mechanisms underlying exosome-mediated LN metastasis in BCa are unclear.

METHODS

We conducted the high-throughput sequencing to explore the expression profile of long noncoding RNA (lncRNA) in urinary exosomes (urinary-EXO) from patients with BCa and further evaluated the clinical relevance of exosomal lncRNA BCYRN1 in a larger 210-case cohort. The functional role of exosomal BCYRN1 was evaluated through the migration and tube formation assays in vitro and the footpad-popliteal LN metastasis model in vivo. RNA pull-down assays, luciferase assays, and actinomycin assays were conducted to detect the regulatory mechanism of exosomal BCYRN1.

RESULTS

LncRNA BCYRN1 was substantially upregulated in urinary-EXO from patients with BCa, and associated with the LN metastasis of BCa. We demonstrated that exosomal BCYRN1 markedly promoted tube formation and migration of human lymphatic endothelial cells (HLECs) in vitro and lymphangiogenesis and LN metastasis of BCa in vivo. Mechanistically, BCYRN1 epigenetically upregulated WNT5A expression by inducing hnRNPA1-associated H3K4 trimethylation in WNT5A promoter, which activated Wnt/β-catenin signaling to facilitate the secretion of VEGF-C in BCa. Moreover, exosomal BCYRN1 was transmitted to HLECs to stabilize the VEGFR3 mRNA and thus formed an hnRNPA1/WNT5A/VEGFR3 feedforward regulatory loop, ultimately promoting the lymphatic metastasis of BCa. Importantly, blocking VEGFR3 with specific inhibitor, SAR131675 significantly impaired exosomal BCYRN1-induced the LN metastasis in vivo. Clinically, exosomal BCYRN1 was positively associated with the shorter survival of BCa patients and identified as a poor prognostic factor of patients.

CONCLUSION

Our results uncover a novel mechanism by which exosomal BCYRN1 synergistically enhances VEGF-C/VEGFR3 signaling-induced lymphatic metastasis of BCa, indicating that BCYRN1 may serve as an encouraging therapeutic target for patients with BCa.

A positive feedback loop between Periostin and TGFβ1 induces and maintains the stemness of hepatocellular carcinoma cells via AP-2α activation

Background

Liver cancer stem cells (LCSCs) play key roles in the metastasis, recurrence, and chemotherapeutic resistance of hepatocellular carcinoma (HCC). Our previous research showed that the POSTN gene is closely related to the malignant progression and poor prognosis of HCC. This study aimed to elucidate the role of POSTN in generating LCSCs and maintaining their stemness as well as the underlying mechanisms.

Methods

Human HCC tissues and matched adjacent normal tissues were obtained from 110 patients. Immunohistochemistry, western blotting (WB), and RT-PCR were performed to detect the expression of POSTN and stemness factors. The roles of transforming growth factor (TGF)-β1 and AP-2α in the POSTN-induced stemness transformation of HCC cells were explored in vitro and in vivo using LCSCs obtained by CD133⁺ cell sorting.

Results

The high expression of POSTN was correlated with the expression of various stemness factors, particularly CD133, in our HCC patient cohort and in TCGA and ICGC datasets. Knockdown of POSTN expression decreased the abilities of HCC cell lines to form tumours in xenograft mouse models. Knockdown of POSTN expression also suppressed cell viability and clone formation, invasion, and sphere formation abilities in vitro. Knockdown of AP-2α attenuated the generation of CD133⁺ LCSCs and their malignant behaviours, indicating that AP-2α was a critical factor that mediated the POSTN-induced stemness transformation and maintenance of HCC cells. The role of AP-2α was verified by using a specific αvβ3 antagonist, cilengitide, in vitro and in vivo. Activation of POSTN could release TGFβ1 from the extracellular matrix and initiated POSTN/TGFβ1 positive feedback signalling. Furthermore, we found that the combined use of cilengitide and lenvatinib suppressed the growth of HCC cells with high POSTN expression more effectively than the use of lenvatinib alone in the patient-derived xenograft (PDX) mouse model.

Conclusions

The POSTN/TGFβ1 positive feedback pathway regulates the expression of stemness factors and the malignant progression of HCC cells by regulating the transcriptional activation of AP-2α. This pathway may serve as a new target for targeted gene therapy in HCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02011-8.

Current understanding of epigenetics mechanism as a novel target in reducing cancer stem cells resistance

At present, after extensive studies in the field of cancer, cancer stem cells (CSCs) have been proposed as a major factor in tumor initiation, progression, metastasis, and recurrence. CSCs are a subpopulation of bulk tumors, with stem cell-like properties and tumorigenic capabilities, having the abilities of self-renewal and differentiation, thereby being able to generate heterogeneous lineages of cancer cells and lead to resistance toward anti-tumor treatments. Highly resistant to conventional chemo- and radiotherapy, CSCs have heterogeneity and can migrate to different organs and metastasize. Recent studies have demonstrated that the population of CSCs and the progression of cancer are increased by the deregulation of different epigenetic pathways having effects on gene expression patterns and key pathways connected with cell proliferation and survival. Further, epigenetic modifications (DNA methylation, histone modifications, and RNA methylations) have been revealed to be key drivers in the formation and maintenance of CSCs. Hence, identifying CSCs and targeting epigenetic pathways therein can offer new insights into the treatment of cancer. In the present review, recent studies are addressed in terms of the characteristics of CSCs, the resistance thereof, and the factors influencing the development thereof, with an emphasis on different types of epigenetic changes in genes and main signaling pathways involved therein. Finally, targeted therapy for CSCs by epigenetic drugs is referred to, which is a new approach in overcoming resistance and recurrence of cancer.

The Landscape of lncRNAs in Hepatocellular Carcinoma: A Translational Perspective

LncRNAs are emerging as relevant regulators of multiple cellular processes involved in cell physiology as well as in the development and progression of human diseases, most notably, cancer. Hepatocellular carcinoma (HCC) is a prominent cause of cancer-related death worldwide due to the high prevalence of causative factors, usual cirrhotic status of the tumor-harboring livers and the suboptimal benefit of locoregional and systemic therapies. Despite huge progress in the molecular characterization of HCC, no oncogenic loop addiction has been identified and most genetic alterations remain non-druggable, underscoring the importance of advancing research in novel approaches for HCC treatment. In this context, long non-coding RNAs (lncRNAs) appear as potentially useful targets as they often exhibit high tumor- and tissue-specific expression and many studies have reported an outstanding dysregulation of lncRNAs in HCC. However, there is a limited perspective of the potential role that deregulated lncRNAs may play in HCC progression and aggressiveness or the mechanisms and therapeutic implications behind such effects. In this review, we offer a clarifying landscape of current efforts to evaluate lncRNA potential as therapeutic targets in HCC using evidence from preclinical models as well as from recent studies on novel oncogenic pathways that show lncRNA-dependency.

Histone deacetylase‑2: A potential regulator and therapeutic target in liver disease (Review)

Histone acetyltransferases are responsible for histone acetylation, while histone deacetylases (HDACs) counteract histone acetylation. An unbalanced dynamic between histone acetylation and deacetylation may lead to aberrant chromatin landscape and chromosomal function. HDAC2, a member of class I HDAC family, serves a crucial role in the modulation of cell signaling, immune response and gene expression. HDAC2 has emerged as a promising therapeutic target for liver disease by regulating gene transcription, chromatin remodeling, signal transduction and nuclear reprogramming, thus receiving attention from researchers and clinicians. The present review introduces biological information of HDAC2 and its physiological and biochemical functions. Secondly, the functional roles of HDAC2 in liver disease are discussed in terms of hepatocyte apoptosis and proliferation, liver regeneration, hepatocellular carcinoma, liver fibrosis and non-alcoholic steatohepatitis. Moreover, abnormal expression of HDAC2 may be involved in the pathogenesis of liver disease, and its expression levels and pharmacological activity may represent potential biomarkers of liver disease. Finally, research on selective HDAC2 inhibitors and non-coding RNAs relevant to HDAC2 expression in liver disease is also reviewed. The aim of the present review was to improve understanding of the multifunctional role and potential regulatory mechanism of HDAC2 in liver disease.

The role of CD133 in hepatocellular carcinoma

Cancer stem cells (CSCs) represent a small subpopulation of cells found within tumors that exhibit properties of self-renewal, like normal stem cells. CSCs have been defined as a crucial factor involved in driving cancer relapse, chemoresistance and metastasis. Prominin-1 (CD133) is one of the most well-characterized markers of CSCs in various tumor types, including hepatocellular carcinoma (HCC). CD133+ cells have been demonstrated to be involved in metastasis, tumorigenesis, tumor recurrence, and resistance to treatment in HCC. CD133-related clinical prognosis prediction, and targeted therapy have highlighted the clinical significance of CD133 in HCC. However, there remains controversy over the role of CD133 in experimental and clinical research involving HCC. In this article, we summarize the fundamental cell biology of CD133 in HCC cells and discuss the important characteristics of CD133+ in HCC cells. Furthermore, the prognostic value of CD133, and therapeutic strategies for its targeting in HCC, is also reviewed.

Insight Into Chromatin-Enriched RNA: A Key Chromatin Regulator in Tumors

Chromatin-enriched RNAs (cheRNAs) constitute a special class of long noncoding RNAs (lncRNAs) that are enriched around chromatin and function to activate neighboring or distal gene transcription. Recent studies have shown that cheRNAs affect chromatin structure and gene expression by recruiting chromatin modifiers or acting as bridges between distal enhancers and promoters. The abnormal transcription of cheRNAs plays an important role in the occurrence of many diseases, particularly tumors. The critical effect of cancer stem cells (CSCs) on the formation and development of tumors is well known, but the function of cheRNAs in tumorigenesis, especially in CSC proliferation and stemness maintenance, is not yet fully understood. This review focuses on the mechanisms of cheRNAs in epigenetic regulation and chromatin conformation and discusses the way cheRNAs function in CSCs to deepen the understanding of tumorigenesis and provide novel insight to advance tumor-targeting therapy.

Decoding the Roles of Long Noncoding RNAs in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide. HCC is associated with several etiological factors, including HBV/HCV infections, cirrhosis, and fatty liver diseases. However, the molecular mechanism underlying HCC development remains largely elusive. The advent of high-throughput sequencing has unveiled an unprecedented discovery of a plethora of long noncoding RNAs (lncRNAs). Despite the lack of coding capacity, lncRNAs have key roles in gene regulation through interacting with various biomolecules. It is increasingly evident that the dysregulation of lncRNAs is inextricably linked to HCC cancer phenotypes, suggesting that lncRNAs are potential prognostic markers and therapeutic targets. In light of the emerging research in the study of the regulatory roles of lncRNAs in HCC, we discuss the association of lncRNAs with HCC. We link the biological processes influenced by lncRNAs to cancer hallmarks in HCC and describe the associated functional mechanisms. This review sheds light on future research directions, including the potential therapeutic applications of lncRNAs.

The Role of Autophagy and lncRNAs in the Maintenance of Cancer Stem Cells

Simple Summary

Cancer stem cells (CSCs) represent a distinct cancer subpopulation that can influence the tumour microenvironment, in addition to cancer progression and relapse. A multitude of factors including CSC properties, long noncoding RNAs (lncRNAs), and autophagy play pivotal roles in maintaining CSCs. We discuss the methods of detection of CSCs and how our knowledge of regulatory and cellular processes, and their interaction with the microenvironment, may lead to more effective targeting of these cells. Autophagy and lncRNAs can regulate several cellular functions, thereby promoting stemness factors and CSC properties, hence understanding this triangle and its associated signalling networks can lead to enhanced therapy response, while paving the way for the development of novel therapeutic approaches.

Abstract

Cancer stem cells (CSCs) possess properties such as self-renewal, resistance to apoptotic cues, quiescence, and DNA-damage repair capacity. Moreover, CSCs strongly influence the tumour microenvironment (TME) and may account for cancer progression, recurrence, and relapse. CSCs represent a distinct subpopulation in tumours and the detection, characterisation, and understanding of the regulatory landscape and cellular processes that govern their maintenance may pave the way to improving prognosis, selective targeted therapy, and therapy outcomes. In this review, we have discussed the characteristics of CSCs identified in various cancer types and the role of autophagy and long noncoding RNAs (lncRNAs) in maintaining the homeostasis of CSCs. Further, we have discussed methods to detect CSCs and strategies for treatment and relapse, taking into account the requirement to inhibit CSC growth and survival within the complex backdrop of cellular processes, microenvironmental interactions, and regulatory networks associated with cancer. Finally, we critique the computationally reinforced triangle of factors inclusive of CSC properties, the process of autophagy, and lncRNA and their associated networks with respect to hypoxia, epithelial-to-mesenchymal transition (EMT), and signalling pathways.

Research Progress on Regulating LncRNAs of Hepatocellular Carcinoma Stem Cells

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies around the world. The self-renewal, proliferation, differentiation, and tumorigenic potential of liver cancer stem cells (LCSCs) may account for the high recurrence rate and the refractory feature of HCC. Despite extensive researches, the underlying regulatory mechanism of LCSCs has not been fully disclosed. Long nonprotein coding RNAs (lncRNAs) may exert an essential role in regulating various biological functions of LCSCs, such as maintaining the stemness of cancer stem cells (CSCs) and promoting tumor development. Therefore, it is highly critical to determine which lncRNAs can control LCSCs functions and understand how LCSCs are regulated by lncRNAs. Herein, we summarized lncRNAs and the main signaling pathways involved in the regulation of LCSCs found in recent years. Moreover, we shed light on the existence of the network system of lncRNAs and LCSCs, which may provide valuable clues on targeting LCSCs.

A novel hypoxic long noncoding RNA KB-1980E6.3 maintains breast cancer stem cell stemness via interacting with IGF2BP1 to facilitate c-Myc mRNA stability

The hostile hypoxic microenvironment takes primary responsibility for the rapid expansion of breast cancer tumors. However, the underlying mechanism is not fully understood. Here, using RNA sequencing (RNA-seq) analysis, we identified a hypoxia-induced long noncoding RNA (lncRNA) KB-1980E6.3, which is aberrantly upregulated in clinical breast cancer tissues and closely correlated with poor prognosis of breast cancer patients. The enhanced lncRNA KB-1980E6.3 facilitates breast cancer stem cells (BCSCs) self-renewal and tumorigenesis under hypoxic microenvironment both in vitro and in vivo. Mechanistically, lncRNA KB-1980E6.3 recruited insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) to form a lncRNA KB-1980E6.3/IGF2BP1/c-Myc signaling axis that retained the stability of c-Myc mRNA through increasing binding of IGF2BP1 with m6A-modified c-Myc coding region instability determinant (CRD) mRNA. In conclusion, we confirm that lncRNA KB-1980E6.3 maintains the stemness of BCSCs through lncRNA KB-1980E6.3/IGF2BP1/c-Myc axis and suggest that disrupting this axis might provide a new therapeutic target for refractory hypoxic tumors.

Advances in Liver Cancer Stem Cell Isolation and their Characterization

Over the last decade research on cancer stem cells (CSC) significantly contributed to a better understanding of tumor biology. Given their similarity to normal stem cells, i.e. self-renewal and pluripotency the need arises to develop robust protocols for the isolation and characterization of CSCs. As with other malignancies, hepatic tumors are composed of a heterogeneous population of cells including liver cancer stem cells (LCSC). Yet, a precise understanding of why stem cells become cancerous is still lacking. There is unmet need to develop robust protocols for the successful isolation of LCSCs from human tissue resection material as to assist in the development of molecular targeted therapies. Here we review the research progress made in the isolation and characterization of LCSCs by considering a wide range of cell surface markers and sorting methods, as applied to side populations, microsphere cultures and the gradient centrifugation method. We emphasize the different fluorescence activated cell sorting methods and the possibility to enrich LCSCs by immunomagnetic beads. We review the specificity of functional assays by considering ABCG transporter and ALDH1 enzyme activities and evaluate the in vivo tumorigenicity of LCSCs in highly sensitive bioassays. Finally, we evaluate different LCSC markers in association with viral and non-viral liver disease and explore the potential of novel drug delivery systems targeting CD133, EpCAM, CD13 and CD90 for the development of molecular targeted therapies. Graphical Abstract.

Hedgehog Signaling, a Critical Pathway Governing the Development and Progression of Hepatocellular Carcinoma

Hedgehog (Hh) signaling is a classic morphogen in controlling embryonic development and tissue repairing. Aberrant activation of Hh signaling has been well documented in liver cancer, including hepatoblastoma, hepatocellular carcinoma (HCC) and cholangiocarcinoma. The present review aims to update the current understanding on how abnormal Hh signaling molecules modulate initiation, progression, drug resistance and metastasis of HCC. The latest relevant literature was reviewed with our recent findings to provide an overview regarding the molecular interplay and clinical relevance of the Hh signaling in HCC management. Hh signaling molecules are involved in the transformation of pre-carcinogenic lesions to malignant features in chronic liver injury, such as nonalcoholic steatohepatitis. Activation of GLI target genes, such as ABCC1 and TAP1, is responsible for drug resistance in hepatoma cells, with a CD133⁻/EpCAM⁻ surface molecular profile, and GLI1 and truncated GLI1 account for the metastatic feature of the hepatoma cells, with upregulation of matrix metalloproteinases. A novel bioassay for the Sonic Hh ligand in tissue specimens may assist HCC diagnosis with negative α-fetoprotein and predict early microvascular invasion. In-depth exploration of the Hh signaling deepens our understanding of its molecular modulation in HCC initiation, drug sensitivity and metastasis, and guides precise management of HCC on an individual basis.

Long non-coding ribonucleic acid W5 inhibits progression and predicts favorable prognosis in hepatocellular carcinoma

BACKGROUND

Accumulating evidence has revealed that several long non-coding ribonucleic acids (lncRNAs) are crucial in the progress of hepatocellular carcinoma (HCC).

AIM

To classify a long non-coding RNA, i.e., lncRNA W5, and to determine the clinical significance and potential roles of lncRNA W5 in HCC.

METHODS

The results showed that lncRNA W5 expression was significantly downregulated in HCC cell lines and tissues. Analysis of the association between lncRNA W5 expression levels and clinicopathological features suggested that low lncRNA W5 expression was related to large tumor size (P < 0.01), poor histological grade (P < 0.05) and serious portal vein tumor thrombosis (P < 0.05). Furthermore, Kaplan-Meier survival analysis showed that low expression of lncRNA W5 predicts poor overall survival (P = 0.016).

RESULTS

Gain-of-loss function experiments, including cell counting kit8 assays, colony formation assays, and transwell assays, were performed in vitro to investigate the biological roles of lncRNA W5. In vitro experiments showed that ectopic overexpression of lncRNA W5 suppressed HCC cell proliferation, migration and invasion; conversely, silencing of lncRNA W5 promoted cell proliferation, migration and invasion. In addition, acting as a tumor suppressor gene in HCC, lncRNA W5 inhibited the growth of HCC xenograft tumors in vivo.

CONCLUSION

These results showed that lncRNA W5 is down-regulated in HCC, and it may suppress HCC progression and predict poor clinical outcomes in patients with HCC. LncRNA W5 may serve as a potential HCC prognostic biomarker in addition to a therapeutic target.

lncRNA PVT1 promotes the migration of gastric cancer by functioning as ceRNA of miR-30a and regulating Snail

Although the incidence and mortality of gastric cancer (GC) are slowly decreasing, the overall prognosis of GC patients with distal metastasis remains dismal. Long non-coding RNA PVT1 has been verified to function as a tumor promoter in several types of cancer. However, the role of PVT1 in GC metastasis remains obscure. Herein, we found that PVT1 was highly expressed in GC tissues and high PVT1 level was associated with tumor stage, lymph node metastasis, and poor prognosis. Overexpression of PVT1 significantly elevated epithelial-to-mesenchymal transition (EMT) marker (N-cadherin, ZEB1, and ZEB2) levels and promoted GC cell EMT process and tumor metastasis in vitro and in vivo. Mechanistically, Snail was identified as a direct target of miR-30a. PVT1 could bind with miR-30a and increase the expression of Snail by acting as a competing endogenous RNA, whereas re-expression of miR-30a in GC cells rescued the EMT markers, decreased Snail level, and inhibited GC cell migration. Taken together, these findings provide a new light on PVT1 in the pathogenesis and development of GC and an important implication for future therapy of the GC.

Long non-coding RNA00844 inhibits MAPK signaling to suppress the progression of hepatocellular carcinoma by targeting AZGP1

Background

Previous data have confirmed that disordered long non-coding ribonucleic acid (lncRNA) expression is evident in many cancers and is correlated with tumor progression. The present study aimed to investigate the function of long non-coding RNA00844 (LINC00844) in hepatocellular carcinoma (HCC).

Methods

The expression levels of target genes were detected with real-time polymerase chain reaction (PCR) and western blotting. The biologic function of HCC cells was determined with cell viability assay, colony formation assay, cell cycle analysis, apoptosis detection, and Transwell migration assay in vitro. Tumorigenesis was performed with cell injection in vivo. The relationship between LINC00844 and survival outcomes was determined with the Cox proportional hazards model. A RNA precipitation assay was conducted to reveal the types of LINC00844 that potentially bind with proteins.

Results

LINC00844 was found to be significantly decreased in HCC tissue and was correlated with poor tumor characteristics, such as portal vein invasion, high α-fetoprotein (AFP), and a high rate of tumor recurrence. Exotic LINC00844 expression in HCC cell lines significantly suppressed proliferation and migration, as well as invasiveness, whereas LINC00844 deletion had the opposite effect. LINC00844 overexpression significantly inhibited HCC tumorigenesis in vivo. Mechanistic analyses indicated that the mitogen-activated protein kinase (MAPK) signaling pathway was remarkably inactivated by LINC00844. Furthermore, the immunoprecipitation assay verified that LINC00844 can bind to zinc-alpha-2-glycoprotein (AZGP1) and interfere with its translocation. LINC00844 can also promote AZGP1 expression, leading to the suppression of the transforming growth factor-β1 (TGF-β1)-extracellular signal-regulated kinase (ERK) pathway.

Conclusions

LINC00844 is a novel anti-oncogene in the development of HCC and a potentially promising therapeutic target in HCC.

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.

Identification of modules and novel prognostic biomarkers in liver cancer through integrated bioinformatics analysis

Liver cancer is a common malignant tumor with poor prognosis. Due to the lack of specific clinical manifestations at early stages, most patients are already at advanced stages of the disease by the time of diagnosis. Identification of novel biomarkers for liver cancer may thus enable earlier detection, improving outcome. MicroRNAs (miRNAs) are small endogenous noncoding RNAs of 18–22 nucleotides in length, which have a regulatory role in the expression of target proteins. Increased evidence suggests that miRNAs are abnormally expressed in a variety of cancer malignancies. Here, we combined RNA sequencing data and clinical information from The Cancer Genome Atlas Liver Hepatocellular Carcinoma database for weighted gene coexpression network analysis to identify potential miRNA prognostic biomarkers. We constructed nine coexpression modules, allowing us to identify that miR‐105‐5p, miR‐767‐5p, miR‐1266‐5p, miR‐4746‐5p, miR‐500a‐3p, miR‐1180‐3p and miR‐139‐5p are significantly associated with liver cancer prognosis. We found that these miRNAs exhibit significant association with prognosis of patients with liver cancer and confirmed the expression of these miRNAs in liver cancer tissues. Multivariate Cox regression analysis showed that miR‐105‐5p and miR‐139‐5p may be considered as independent factors. In summary, here we report that seven miRNAs have potential value as prognostic biomarkers of liver cancer.

Comprehensive analysis of transcriptome data stemness indices identifies key genes for controlling cancer stem cell characteristics in gastric cancer

BACKGROUND

Cancer stem cells (CSCs) are the tumor cell of origin with self-renewing ability and multi-differentiation potency. CSCs can play vital roles in gastric cancer (GC) metastasis and relapse. However, the genes that regulate the stemness maintenance of CSCs in GC patients remain largely unknown. In the present study, we sought to determine the key genes associated with stemness in GC patients.

METHODS

mRNA expression-based stemness index (mRNA SI) was analyzed with regard to the differential expression levels between normal and GC tissues, as well as clinical features and survival outcomes. Weighted gene co-expression network analysis (WGCNA) was performed to identify modules of interest and key genes. The differences in mRNA expression of key genes between normal and GC tissues were calculated by "ggpubr" package in R. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) analysis were carried out to annotate the function of key genes. Protein-protein interaction (PPI) and gene co-expression analyses were conducted using STRING and "corrplot" package in R, respectively.

RESULTS

mRNA SI score was markedly increased in GC tumor compared to normal tissues. High mRNA SI score was remarkably associated with more advanced tumor stage and higher pathologic grade, but longer survival times. Based on the results of WGCNA, 19 key genes (i.e., BUB1, BUB1B, KIF14, NCAPH, RACGAP1, KIF15, CENPF, TPX2, RAD54L, KIF18B, TTX, KIF4A, SGO2, PLK4, ARHGAP11A, XRCC2, C1orf112, NCAPG, ORC6) were identified. GO and KEGG functional analyses revealed that these 19 key genes were mainly related to cell proliferation. From PPI and gene co-expression analyses, these 19 key genes were discovered to be intensively associated with each other at both protein and transcription levels.

CONCLUSIONS

our study identified 19 key genes that play vital roles in the stemness maintenance of CSCs in GC patients. Targeting these key genes may help to control CSC characteristics in GC.

LINC00294 induced by GRP78 promotes cervical cancer development by promoting cell cycle transition

Cervical cancer is one of the most common gynecological malignancies, and it has become a crucial public health problem. In the present study, the expression profiles of cervical cancer and normal cervical tissues were downloaded from the Gene Expression Omnibus and The Cancer Genome Atlas databases. Subsequently, the dysregulated long non-coding RNAs (lncRNAs) in cervical cancer were identified using R software Differentially expressed lncRNAs in cervical cancer that were associated with glucose-regulated protein 78 (GRP78) were screened out and the results demonstrated that eight lncRNAs were strongly positively correlated with GRP78. In order to confirm the relationship between GRP78 and candidate lncRNAs, GRP78 small interfering RNA (siRNA) was transfected into HeLa cells. The target lncRNAs that were regulated by GRP78 were then identified by reverse transcription-quantitative PCR and it was revealed that LINC00294 was significantly downregulated following GRP78-knockdown. Subsequently, Gene Set Enrichment Analysis demonstrated that LINC00294 was mainly enriched in regulating the cell cycle and the Hedgehog pathway. Following transfection of HeLa and SiHa cells with LINC00294 siRNA, the cell cycle was arrested at the G0/G1 phase. Western blotting suggested that LINC00294-knockdown downregulated the expression of cell cycle-associated factors (cyclin D, cyclin E and cyclin Dependent kinase 4) and upregulated cell cycle inhibitory factors (p16 and p21). The Hedgehog pathway was inhibited following knockdown of LINC00294 in HeLa and SiHa cells. In summary, LINC00294 induced by GRP78 promoted the progression of cervical cancer by regulating the cell cycle via Hedgehog pathway.

Emerging roles and potential clinical applications of noncoding RNAs in hepatocellular carcinoma

Hepatocellular carcinoma(HCC) is one of the most common forms of cancer, and accounts for a high proportion of cancer-associated deaths. Growing evidences have demonstrated that non- protein-coding regions of the genome could give rise to transcripts, termed noncoding RNA (ncRNA), that form novel functional layers of the cellular activity. ncRNAs are implicated in different molecular mechanisms and functions at transcriptional, translational and post-translational levels. An increasing number of studies have demonstrated a complex array of molecular and cellular functions of ncRNAs in different stages of the HCC tumorigenesis, either in an oncogenic or tumor-suppressive manner. As a result, several pre-clinical studies have highlighted the great potentials of ncRNAs as novel biomarkers for cancer diagnosis or therapeutics in targeting HCC progression. In this review, we briefly described the characteristics of several representative ncRNAs and summarized the latest findings of their roles and mechanisms in the development of HCC, in order to better understand the cancer biology and their potential clinical applications in this malignancy.

Dual Effects of Non-Coding RNAs (ncRNAs) in Cancer Stem Cell Biology

The identification of cancer stem cells (CSCs) as initiators of carcinogenesis has revolutionized the era of cancer research and our perception for the disease treatment options. Additional CSC features, including self-renewal and migratory and invasive capabilities, have further justified these cells as putative diagnostic, prognostic, and therapeutic targets. Given the CSC plasticity, the identification of CSC-related biomarkers has been a serious burden in CSC characterization and therapeutic targeting. Over the past decades, a compelling amount of evidence has demonstrated critical regulatory functions of non-coding RNAs (ncRNAs) on the exclusive features of CSCs. We now know that ncRNAs may interfere with signaling pathways, vital for CSC phenotype maintenance, such as Notch, Wnt, and Hedgehog. Here, we discuss the multifaceted contribution of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as representative ncRNA classes, in sustaining the CSC-like traits, as well as the underlying molecular mechanisms of their action in various CSC types. We further discuss the use of CSC-related ncRNAs as putative biomarkers of high diagnostic, prognostic, and therapeutic value.

Glycochenodeoxycholic acid induces stemness and chemoresistance via the STAT3 signaling pathway in hepatocellular carcinoma cells

The poor prognosis of hepatocellular carcinoma (HCC) is primarily attributed to its high frequency of recurrence and resistance to chemotherapy. Epithelial-to-mesenchymal transition (EMT) and the acquisition of cancer stem cells (CSCs) are the fundamental drivers of chemoresistance in HCC. Glycochenodeoxycholic acid (GCDC), a component of bile acid (BA), has been reported to induce necrosis in primary human hepatocytes. In the present work, we investigated the function of GCDC in HCC chemoresistance. We found that GCDC promoted chemoresistance in HCC cells by down-regulating and up-regulating the expression of apoptotic and anti-apoptotic genes, respectively. Furthermore, GCDC induced the EMT phenotype and stemness in HCC cells and activated the STAT3 signaling pathway. These findings reveal that GCDC promotes chemoresistance in HCC by inducing stemness via the STAT3 pathway and could be a potential target in HCC chemotherapy.

Intratumoral heterogeneity of hepatocellular carcinoma: From single-cell to population-based studies

Hepatocellular carcinoma (HCC) is characterized by high heterogeneity in both intratumoral and interpatient manners. While interpatient heterogeneity is related to personalized therapy, intratumoral heterogeneity (ITH) largely influences the efficacy of therapies in individuals. ITH contributes to tumor growth, metastasis, recurrence, and drug resistance and consequently limits the prognosis of patients with HCC. There is an urgent need to understand the causes, characteristics, and consequences of tumor heterogeneity in HCC for the purposes of guiding clinical practice and improving survival. Here, we summarize the studies and technologies that describe ITH in HCC to gain insight into the origin and evolutionary process of heterogeneity. In parallel, evidence is collected to delineate the dynamic relationship between ITH and the tumor ecosystem. We suggest that conducting comprehensive studies of ITH using single-cell approaches in temporal and spatial dimensions, combined with population-based clinical trials, will help to clarify the clinical implications of ITH, develop novel intervention strategies, and improve patient prognosis.

Cancer Stem Cell Functions in Hepatocellular Carcinoma and Comprehensive Therapeutic Strategies

Hepatocellular carcinoma (HCC) is a significant cause of cancer-related mortality owing to resistance to traditional treatments and tumor recurrence after therapy, which leads to poor therapeutic outcomes. Cancer stem cells (CSC) are a small subset of tumor cells with the capability to influence self-renewal, differentiation, and tumorigenesis. A number of surface markers for liver cancer stem cell (LCSC) subpopulations (EpCAM, CD133, CD44, CD13, CD90, OV-6, CD47, and side populations) in HCC have been identified. LCSCs play critical roles in regulating HCC stemness, self-renewal, tumorigenicity, metastasis, recurrence, and therapeutic resistance via genetic mutations, epigenetic disruption, signaling pathway dysregulation, or alterations microenvironment. Accumulating studies have shown that biomarkers for LCSCs contribute to diagnosis and prognosis prediction of HCC, supporting their utility in clinical management and development of therapeutic strategies. Preclinical and clinical analyses of therapeutic approaches for HCC using small molecule inhibitors, oncolytic measles viruses, and anti-surface marker antibodies have demonstrated selective, efficient, and safe targeting of LCSC populations. The current review focuses on recent reports on the influence of LCSCs on HCC stemness, tumorigenesis, and multiple drug resistance (MDR), along with LCSC-targeted therapeutic strategies for HCC.

LncRNA SNHG6 plays an oncogenic role in colorectal cancer and can be used as a prognostic biomarker for solid tumors

Small nucleolar RNA host gene 6 (SNHG6) has been recognized as an oncogene in numerous cancers and overexpression of SNHG6 was found to promote colorectal cancer (CRC). Hence, we performed a meta-analysis to examine the clinical importance of the long noncoding RNA (lncRNA) SNHG6. Moreover, comprehensive identification of RNA-binding proteins-mass spectrometry (ChIRP-MS) was conducted to explore the carcinogenic mechanism of lncRNA SNHG6 in CRC. Fourteen studies conducted on 1,139 patients were included in this meta-analysis. We also constructed the protein-protein interactive (PPI) network in string based on the ChIRP-MS results and cytoscape was used to identify core modules in the PPI network, which were then analyzed using the bioinformatics websites, cancer single-cell state atlas (CancerSEA) and G:profilter. The clinical outcomes of the meta-analysis indicated that higher expression of SNHG6 was related with a poorer survival outcome (overall survival: hazard ratio (HR) = 1.92; 95% confidence interval [Cl]: 1.48, 2.49; p < .0001; disease-free survival: HR = 1.84; 95% Cl: 1.02, 3.34; p = .044), higher tumor stage (odds ratio [OR] = 3.35; 95% Cl: 2.57, 4.37; p < .0001), distant metastasis (OR = 1.83; 95% Cl: 1.11, 2.99; p = .017) and lymph node metastasis (OR = 1.33; 95% Cl: 0.93, 1.89; p = .119). The ChIRP-MS results showed that core Module 1 of the PPI was significant in ribosomes and core Module 2 was mainly related to spliceosomes and messenger RNA processing. In conclusion, a higher expression of SNHG6 was found to be associated with a poorer survival outcome, high tumor stage, and distant metastasis in various solid tumors. SNHG6 was also found to be able to affect the processes of transcription and translation to promote CRC.

Cancer stemness in hepatocellular carcinoma: mechanisms and translational potential

Cancer stemness, referring to the stem-cell-like phenotype of cancer cells, has been recognised to play important roles in different aspects of hepatocarcinogenesis. A number of well-established cell-surface markers already exist for liver cancer stem cells, with potential new markers of liver cancer stem cells being identified. Both genetic and epigenetic factors that affect various signalling pathways are known to contribute to cancer stemness. In addition, the tumour microenvironment—both physical and cellular—is known to play an important role in regulating cancer stemness, and the potential interaction between cancer stem cells and their microenvironment has provided insight into the regulation of the tumour-initiating ability as well as the cellular plasticity of liver CSCs. Potential specific therapeutic targeting of liver cancer stemness is also discussed. With increased knowledge, effective druggable targets might be identified, with the aim of improving treatment outcome by reducing chemoresistance.

Targeting cancer stem cell pathways for cancer therapy

Since cancer stem cells (CSCs) were first identified in leukemia in 1994, they have been considered promising therapeutic targets for cancer therapy. These cells have self-renewal capacity and differentiation potential and contribute to multiple tumor malignancies, such as recurrence, metastasis, heterogeneity, multidrug resistance, and radiation resistance. The biological activities of CSCs are regulated by several pluripotent transcription factors, such as OCT4, Sox2, Nanog, KLF4, and MYC. In addition, many intracellular signaling pathways, such as Wnt, NF-κB (nuclear factor-κB), Notch, Hedgehog, JAK-STAT (Janus kinase/signal transducers and activators of transcription), PI3K/AKT/mTOR (phosphoinositide 3-kinase/AKT/mammalian target of rapamycin), TGF (transforming growth factor)/SMAD, and PPAR (peroxisome proliferator-activated receptor), as well as extracellular factors, such as vascular niches, hypoxia, tumor-associated macrophages, cancer-associated fibroblasts, cancer-associated mesenchymal stem cells, extracellular matrix, and exosomes, have been shown to be very important regulators of CSCs. Molecules, vaccines, antibodies, and CAR-T (chimeric antigen receptor T cell) cells have been developed to specifically target CSCs, and some of these factors are already undergoing clinical trials. This review summarizes the characterization and identification of CSCs, depicts major factors and pathways that regulate CSC development, and discusses potential targeted therapy for CSCs.

CD73 sustained cancer-stem-cell traits by promoting SOX9 expression and stability in hepatocellular carcinoma

Background

Aberrant AKT activation contributes to cancer stem cell (CSC) traits in hepatocellular carcinoma (HCC). We previously reported that CD73 activated AKT signaling via the Rap1/P110β cascade. Here, we further explored the roles of CD73 in regulating CSC characteristics of HCC.

Methods

CD73 expression modulations were conducted by lentiviral transfections. CD73+ fractions were purified by magnetic-based sorting, and fluorescent-activated cell sorting was used to assess differentiation potentials. A sphere-forming assay was performed to evaluate CSC traits in vitro, subcutaneous NOD/SCID mice models were generated to assess in vivo CSC features, and colony formation assays assessed drug resistance capacities. Stemness-associated gene expression was also determined, and underlying mechanisms were investigated by evaluating immunoprecipitation and ubiquitylation.

Results

We found CD73 expression was positively associated with sphere-forming capacity and elevated in HCC spheroids. CD73 knockdown hindered sphere formation, Lenvatinib resistance, and stemness-associated gene expression, while CD73 overexpression achieved the opposite effects. Moreover, CD73 knockdown significantly inhibited the in vivo tumor propagation capacity. Notably, we found that CD73+ cells exhibited substantially stronger CSC traits than their CD73– counterparts. Mechanistically, CD73 exerted its pro-stemness activity through dual AKT-dependent mechanisms: activating SOX9 transcription via c-Myc, and preventing SOX9 degradation by inhibiting glycogen synthase kinase 3β. Clinically, the combined analysis of CD73 and SOX9 achieved a more accurate prediction of prognosis.

Conclusions

Collectively, CD73 plays a critical role in sustaining CSCs traits by upregulating SOX9 expression and enhancing its protein stability. Targeting CD73 might be a promising strategy to eradicate CSCs and reverse Lenvatinib resistance in HCC.

HIF-1ɑ-regulated miR-1275 maintains stem cell-like phenotypes and promotes the progression of LUAD by simultaneously activating Wnt/β-catenin and Notch signaling

Rationale: Cancer stem cells (CSCs) are considered to be essential for tumorigenesis, recurrence, and metastasis and therefore serve as a biomarker for tumor progression in diverse cancers. Recent studies have illustrated that specific miRNAs exhibit novel therapeutic potential by controlling CSC properties. miR-1275 is upregulated in lung adenocarcinoma (LUAD) and enhances its stemness. However, the underlying mechanisms have not been elucidated.

Methods: miRNA expression microarray of LUAD and adjacent nontumor tissues was used to identify miRNAs involved in LUAD malignant progression. miR-1275 expression level was determined using quantitative real-time PCR (RT-qPCR) and in situ hybridization (ISH), and its correlation with clinicopathological characteristics was analyzed in LUAD specimens. The upstream regulator of miR-1275 was validated by chromatin immunoprecipitation (ChIP). The biological functions and underlying mechanisms of miR-1275 were investigated both in vitro and in vivo.

Results: MiR-1275 was highly upregulated in lung cancer cell lines and LUAD tissues. Overexpression of miR-1275 in lung cancer patients was associated with shorter overall- and recurrence-free-survival. Proto-oncogene HIF-1ɑ was identified as the transcription mediator of miR-1275. Activation of Wnt/β-catenin and Notch signaling by miR-1275 was found to enhance the stemness of LUAD cells, while antagonizing miR-1275 or suppressing Wnt/β-catenin and Notch pathways potently reversed miR-1275-induced pathway co-activation and stemness. Enhanced stemness dramatically promoted tumorigenicity, recurrence, and metastasis. miR-1275 directly targeted multiple antagonists of Wnt/β-catenin and Notch pathways, including DKK3, SFRP1, GSK3β, RUNX3, and NUMB, respectively, which resulted in signaling activation.

Conclusions: Our findings identified miR-1275 as a potential oncogene in LUAD that exerts its tumorigenic effect through co-activating Wnt/β-catenin and Notch signaling pathways. Thus, HIF-1ɑ-regulated miR-1275 might be a potential therapeutic target for LUAD.

Lnc-RP5 Regulates the miR-129-5p/Notch1/PFV Internal Promoter Axis to Promote the Expression of the Prototype Foamy Virus Transactivator Tas

Prototype foamy virus (PFV) is a unique retrovirus that infects animals and humans and does not cause clinical symptoms. Long noncoding RNAs (lncRNAs) are believed to exert multiple regulatory functions during viral infections. Previously, we utilized RNA sequencing (RNA-seq) to characterize and identify the lncRNA lnc-RP5-1086D14.3.1-1:1 (lnc-RP5), which is markedly decreased in PFV-infected cells. However, little is known about the function of lnc-RP5 during PFV infection. In this study, we identified lnc-RP5 as a regulator of the PFV transcriptional transactivator (Tas). Lnc-RP5 enhanced the activity of the PFV internal promoter (IP). The expression of PFV Tas was found to be promoted by lnc-RP5. Moreover, miR-129-5p was found to be involved in the lnc-RP5-mediated promotion of PFV IP activity, while the Notch1 protein suppressed the activity of PFV IP and the expression of Tas. Our results demonstrate that lnc-RP5 promotes the expression of PFV Tas through the miR-129-5p/Notch1/PFV IP axis. This work provides evidence that host lncRNAs can manipulate PFV replication by employing miRNAs and proteins during an early viral infection.

Matrine suppression of self-renewal was dependent on regulation of LIN28A/Let-7 pathway in breast cancer stem cells

Matrine, a natural product extracted from the root of Sophora flavescens Ait, was the main chemical ingredient of compounds of Kushen injection, which has been widely used for its remarkable anticancer effects for years. The underlying mechanisms for Matrine regulations of human breast cancer stem cells (BrCSCs) are barely known. LIN28, a well-characterized suppressor of Let-7 microRNA biogenesis, playing vital roles in regulations of stem cells' renewal and tumorigenesis. Here we show that the compounds of Kushen injection derived Matrine could suppress the BrCSCs differentiation and self-renewal through downregulating the expression of Lin28A, resulting in the inactivation of Wnt pathway through a Let-7b-dependent way. In opposite to Matrine, Cisplatin treatment increases the ability of tumorsphere formation and the expression of BrCSCs markers, which was partially blocked by either Let-7b overexpression or CCND1 inhibition. Furthermore, Matrine sensitized BrCSCs to cisplatin's suppression of cancer expansion in vitro and in vivo. Our study uncovers the role of the LIN28A/Let-7 in BrCSCs renewal, and more importantly, elucidated a novel mechanism by which Matrine induces breast cancer involution.

Role of CircRNAs_100395 in Proliferation and Metastases of Liver Cancer

BACKGROUND Circular RNAs (circRNAs) are a kind of noncoding RNA with high cancer-specific expression, and great potential in regulating tumorigenesis. Among these, circRNA_100395 (circ_100395) has been reported to be downregulated in lung cancer, and participates in the process of tumor cell proliferation and metastasis. However, its expression and function in liver cancer remain unknown. MATERIAL AND METHODS Quantitative real-time polymerase chain reaction (RT-qPCR) was used to evaluate the expression level of circ_100395 and microRNAs-1228 (miR-1228) in liver cancer samples and the adjacent non-tumor tissues. Cell proliferation, apoptosis, invasion, migration, and epithelial-mesenchymal transition (EMT) pathway of circ_100395 upregulated cells were analyzed using a Cell Counting Kit-8 (CCK-8), flow cytometry, Transwell assay, and Western blot analysis. RESULTS We found that circ_100395 was downregulated in cancerous liver tissues relative to the adjacent normal tissues. The overexpression of circ_100395 was negatively associated with tumor differentiation, microvascular invasion, and portal vein tumor thrombosis. However, patients with higher circ_10039 expression tended to have better postoperative disease-free survival time. Moreover, upregulation of circ_100395 in liver cancer cells inhibited cell proliferation, induced apoptosis, then silenced the EMT pathway and reduced migration and invasion abilities, while this anti-tumor effect was significantly reversed by the downstream target, miR-1228. CONCLUSIONS circ_100395 appears to be a promising therapeutic target for liver cancer.

Cancer stem cell (CSC) resistance drivers

Cancer stem cells (CSCs) are a population of self-renewal cells with high tumorigenic potency. CSCs can adopt easily with changes in the nearby milieu, and are more resistant to conventional therapies than other cells within a tumor. CSC resistance can be induced secondary to radio- and chemotherapy, or even after chemotherapy secession. A combination of both intrinsic and extrinsic factors is contributed to CSC-mediated therapy resistance. CSCs represent protective autophagy and efficient cell cycling, along with highly qualified epithelial-mesenchymal transition (EMT) regulators, reactive oxygen species (ROS) scavengers, drug transporters, and anti-apoptotic and DNA repairing systems. In addition, CSCs develop cross-talking and share some characteristics with other cells within the tumor microenvironment (TME) being more intense in higher stage tumors, and thereby sophisticating tumor-targeted therapies. TME, in fact, is a nest for aggravating resistance mechanisms in CSCs. TME is exposed constantly to the nutritional, metabolic and oxygen deprivation; these conditions promote CSC adaptation. This review is aimed to discuss main (intrinsic and extrinsic) mechanisms of CSC resistance and suggest some strategies to revoke this important promoter of therapy failure.