Zinc finger protein X-linked promotes expansion of EpCAM+ cancer stem-like cells in hepatocellular carcinoma

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

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

A conserved ZFX/WNT3 axis modulates the growth and imatinib response of chronic myeloid leukemia stem/progenitor cells

BACKGROUND

Zinc finger protein X-linked (ZFX) has been shown to promote the growth of tumor cells, including leukemic cells. However, the role of ZFX in the growth and drug response of chronic myeloid leukemia (CML) stem/progenitor cells remains unclear.

METHODS

Real-time quantitative PCR (RT-qPCR) and immunofluorescence were used to analyze the expression of ZFX and WNT3 in CML CD34+ cells compared with normal control cells. Short hairpin RNAs (shRNAs) and clustered regularly interspaced short palindromic repeats/dead CRISPR-associated protein 9 (CRISPR/dCas9) technologies were used to study the role of ZFX in growth and drug response of CML cells. Microarray data were generated to compare ZFX-silenced CML CD34+ cells with their controls. Chromatin immunoprecipitation (ChIP) and luciferase reporter assays were performed to study the molecular mechanisms of ZFX to regulate WNT3 expression. RT-qPCR and western blotting were used to study the effect of ZFX on β-catenin signaling.

RESULTS

We showed that ZFX expression was significantly higher in CML CD34+ cells than in control cells. Overexpression and gene silencing experiments indicated that ZFX promoted the in vitro growth of CML cells, conferred imatinib mesylate (IM) resistance to these cells, and enhanced BCR/ABL-induced malignant transformation. Microarray data and subsequent validation revealed that WNT3 transcription was conservatively regulated by ZFX. WNT3 was highly expressed in CML CD34+ cells, and WNT3 regulated the growth and IM response of these cells similarly to ZFX. Moreover, WNT3 overexpression partially rescued ZFX silencing-induced growth inhibition and IM hypersensitivity. ZFX silencing decreased WNT3/β-catenin signaling, including c-MYC and CCND1 expression.

CONCLUSION

The present study identified a novel ZFX/WNT3 axis that modulates the growth and IM response of CML stem/progenitor cells.

The functions and roles of C2H2 zinc finger proteins in hepatocellular carcinoma

C2H2 zinc finger (C2H2-ZF) proteins are the majority group of human transcription factors and they have many different molecular functions through different combinations of zinc finger domains. Hepatocellular carcinoma (HCC) is one of the most prevalent malignant tumors and the main reason for cancer-related deaths worldwide. More and more findings support the abnormal expression of C2H2-ZF protein in the onset and progression of HCC. The C2H2-ZF proteins are involved in various biological functions in HCC, such as EMT, stemness maintenance, metabolic reprogramming, cell proliferation and growth, apoptosis, and genomic integrity. The study of anti-tumor drug resistance also highlights the pivotal roles of C2H2-ZF proteins at the intersection of biological functions (EMT, stemness maintenance, autophagy)and chemoresistance in HCC. The involvement of C2H2-ZF protein found recently in regulating different molecules, signal pathways and pathophysiological activities indicate these proteins as the possible therapeutic targets, and diagnostic or prognostic biomarkers for HCC.

Structures and biological functions of zinc finger proteins and their roles in hepatocellular carcinoma

Zinc finger proteins are transcription factors with the finger domain, which plays a significant role in gene regulation. As the largest family of transcription factors in the human genome, zinc finger (ZNF) proteins are characterized by their different DNA binding motifs, such as C2H2 and Gag knuckle. Different kinds of zinc finger motifs exhibit a wide variety of biological functions. Zinc finger proteins have been reported in various diseases, especially in several cancers. Hepatocellular carcinoma (HCC) is the third leading cause of cancer-associated death worldwide, especially in China. Most of HCC patients have suffered from hepatitis B virus (HBV) and hepatitis C virus (HCV) injection for a long time. Although the surgical operation of HCC has been extremely developed, the prognosis of HCC is still very poor, and the underlying mechanisms in HCC tumorigenesis are still not completely understood. Here, we summarize multiple functions and recent research of zinc finger proteins in HCC tumorigenesis and progression. We also discuss the significance of zinc finger proteins in HCC diagnosis and prognostic evaluation.

Kinesin family member 2C promotes hepatocellular carcinoma growth and metastasis via activating MEK/ERK pathway

The current work was intended to explore the function and mechanism of Kinesin family member 2C (KIF2C) in hepatocellular carcinoma (HCC). In this study, KIF2C expression was at a high level in HCC and indicated poor prognosis. Silencing KIF2C significantly suppressed the proliferation, migration, and invasion in HCC cells. Furthermore, silencing KIF2C markedly decreased the expression of Snail, Vimentin, p-MEK, and p-ERK, but increased E-cadherin expression in HCC cells. Moreover, we also found that MEK/ERK inhibitor U0126 could enhance the impact on cell proliferation, migration, and invasion induced by silencing KIF2C in HCC. On the contrary, MEK/ERK activator PAF could weaken the impact induced by silencing KIF2C in HCC. Thus, our findings indicate that KIF2C can promote the proliferation, migration, and invasion by activating MEK/ERK pathway in HCC.

A 14-Marker Multiplexed Imaging Panel for Prognostic Biomarkers and Tumor Heterogeneity in Head and Neck Squamous Cell Carcinoma

Recent advances made in treatment for head and neck squamous cell carcinoma (HNSCC) highlight the need for new prediction tools to guide therapeutic strategies. In this study, we aimed to develop a HNSCC-targeting multiplex immunohistochemical (IHC) panel that can evaluate prognostic factors and the intratumor heterogeneity of HNSCC. To identify IHC-based tissue biomarkers that constitute new multiplex IHC panel, a systematic review and meta-analysis were performed to analyze reported IHC biomarkers in laryngeal and pharyngeal SCC in the period of 2008–2018. The Cancer Genome Atlas (TCGA) and Reactome pathway databases were used to validate the prognostic and functional significance of the identified biomarkers. A 14-marker chromogenic multiplex IHC panel including identified biomarkers was used to analyze untreated HNSCC tissue. Forty-five high-quality studies and thirty-one candidate tissue biomarkers were identified (N = 7062). Prognostic validation in TCGA laryngeal and pharyngeal SCC cohort (N = 205) showed that β-catenin, DKK1, PINCH1, ADAM10, and TIMP1 were significantly associated with poor prognosis, which were related to functional categories such as immune system, cellular response, cell cycle, and developmental systems. Selected biomarkers were assembled to build a 14-marker panel, evaluating heterogeneity and polarized expression of tumor biomarkers in the tissue structures, which was particularly related to activation of Wnt/β-catenin pathway. Integrated IHC analysis based on a systemic review and meta-analysis provides an in situ proteomics tool to assess the aggressiveness and intratumor heterogeneity of HNSCC.

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.

Sex-Associated Gene Expression Alterations Correlate With Esophageal Cancer Survival

OBJECTIVES:

Esophageal cancer (EC) is a significant cause of cancer death with 5-year survival of 10%–15% and males more frequently affected. Genetic evaluation for loci highlighting risk has been performed, but survival data are limited. The Cancer Genome Atlas (TCGA) data sets allow for potential prognostic marker assessment in large patient cohorts. The study aimed to use the TCGA EC data set to assess whether survival varies by sex and explore genetic alterations that may explain variation observed.

METHODS:

TCGA clinical/RNA-seq data sets (n = 185, 158 males/27 females) were downloaded from the cancer genome browser. Data analysis/figure preparation was performed in R and GraphPad Prism 7. Survival analysis was performed using the survival package. Text mining of PubMed was performed using the tm, RISmed, and wordcloud packages. Pathway analysis was performed using the Reactome database.

RESULTS:

In EC, male sex/high tumor grade reduced overall survival (hazard ratio = 2.27 [0.99–5.24] for M vs F and 2.49 [0.89–6.92] for low vs high grade, respectively) and recurrence-free survival (hazard ratio = 4.09 [0.98–17.03] for M vs F and 3.36 [0.81–14.01] for low vs high grade, respectively). To investigate the genetic basis for sex-based survival differences in EC, corresponding gene expression data were analyzed. Sixty-nine genes were dysregulated at the P < 0.01 level by the Wilcox test, 33% were X-chromosome genes, and 7% were Y-chromosome genes.

DISCUSSION:

Female sex potentially confers an EC survival advantage. Importantly, we demonstrate a genetic/epigenetic basis for these survival differences that are independent of lifestyle-associated risk factors overrepresented in males. Further research may lead to novel concepts in treating/measuring EC aggressiveness by sex.

The miR-93-3p/ZFP36L1/ZFX axis regulates keratinocyte proliferation and migration during skin wound healing

Keratinocyte proliferation and migration are crucial steps during skin wound healing. The functional role of microRNAs (miRs) remains relatively unknown during this process. miR-93 levels have been reported to increase within 24 h of skin wound healing; however, whether miR-93-3p or miR-93-5p plays a specific role in wound healing is yet to be studied. In this study, with the use of an in vivo mouse skin wound-healing model, we demonstrate that miR-93-3p is significantly upregulated, whereas there is no change in the expression of miR-93-5p during skin wound healing. In HaCaT cells, miR-93-3p overexpression increased proliferation and migration of the cells, whereas miR-93-3p inhibition had the reverse effect. Additionally, it was evident that ZFP36L1 was a direct target of miR-93-3p in keratinocytes. Further, ZFP36L1 silencing mirrored the consequences observed during miR-93-3p overexpression on both proliferation and migration of keratinocytes. In addition, we demonstrate that zinc-finger X-linked (ZFX), as a target for ZFP36L1, is involved in the promotion of the miR-93-3p/ZFP36L1 axis in keratinocyte proliferation and migration. Ultimately, we found that mouse skin wound model treatment with anti-miR-93-3p delayed wound healing. Overall, our results show that miR-93-3p is a crucial regulator of skin wound healing that facilitates keratinocyte proliferation and migration through ZFP36L1/ZFX axis.

Recent Advances in Liver Cancer Stem Cells: Non-coding RNAs, Oncogenes and Oncoproteins

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies worldwide, with high morbidity, relapse, metastasis and mortality rates. Although liver surgical resection, transplantation, chemotherapy, radiotherapy and some molecular targeted therapeutics may prolong the survival of HCC patients to a certain degree, the curative effect is still poor, primarily because of tumor recurrence and the drug resistance of HCC cells. Liver cancer stem cells (LCSCs), also known as liver tumor-initiating cells, represent one small subset of cancer cells that are responsible for disease recurrence, drug resistance and death. Therefore, understanding the regulatory mechanism of LCSCs in HCC is of vital importance. Thus, new studies that present gene regulation strategies to control LCSC differentiation and replication are under development. In this review, we provide an update on the latest advances in experimental studies on non-coding RNAs (ncRNAs), oncogenes and oncoproteins. All the articles addressed the crosstalk between different ncRNAs, oncogenes and oncoproteins, as well as their upstream and downstream products targeting LCSCs. In this review, we summarize three pathways, the Wnt/β-catenin signaling pathway, phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway, and interleukin 6/Janus kinase 2/signal transducer and activator of transcription 3 (IL6/JAK2/STAT3) signaling pathway, and their targeting gene, c-Myc. Furthermore, we conclude that octamer 4 (OCT4) and Nanog are two important functional genes that play a pivotal role in LCSC regulation and HCC prognosis.

The Cancer Stem Cell in Hepatocellular Carcinoma

The recognition of intra-tumoral cellular heterogeneity has given way to the concept of the cancer stem cell (CSC). According to this concept, CSCs are able to self-renew and differentiate into all of the cancer cell lineages present within the tumor, placing the CSC at the top of a hierarchical tree. The observation that these cells—in contrast to bulk tumor cells—are able to exclusively initiate new tumors, initiate metastatic spread and resist chemotherapy implies that CSCs are solely responsible for tumor recurrence and should be therapeutically targeted. Toward this end, dissecting and understanding the biology of CSCs should translate into new clinical therapeutic approaches. In this article, we review the CSC concept in cancer, with a special focus on hepatocellular carcinoma.

NMIIA promotes tumor growth and metastasis by activating the Wnt/β-catenin signaling pathway and EMT in pancreatic cancer

Non-muscle myosin IIA (NMIIA) protein plays an important role in cell cytokinesis and cell migration. The role and underlying regulatory mechanisms of NMIIA in pancreatic cancer (PC) remain elusive. We found that NMIIA is highly expressed in PC tissues and contributes to PC poor progression by using open microarray datasets from the Gene Expression Omnibus (GEO), The Cancer Genome Atlas (TCGA), and PC tissue arrays. NMIIA regulates β-catenin mediated EMT to promote the proliferation, migration, invasion, and sphere formation of PC cells in vitro and in vivo. NMIIA controls the β-catenin transcriptional activity by interacting with β-catenin. Moreover, MEK/ERK signaling is critical in MLC2 (Ser19) phosphorylation, which can mediate NMIIA activity and regulate Wnt/β-catenin signaling. These findings highlight the significance of NMIIA in tumor regression and implicate NMIIA as a promising candidate for PC treatment.

Cell division cycle 20 (CDC20) drives prostate cancer progression via stabilization of β-catenin in cancer stem-like cells

Background

Cell division cycle 20 (CDC20) is frequently overexpressed in malignant tumours and involved in the differentiation process of hematopoietic stem cells. However, the role of CDC20 in prostate cancer stem-like cells (CSCs) remains poorly understood.

Methods

The expression of CDC20, CD44, β-catenin were examined in prostate cancer specimens by immunohistochemistry assay, the role of CDC20 on the stem-like properties of prostate CSCs was accessed by real-time quantitive PCR, spheroid formation, in vitro and in vivo limiting dilution assay.

Finding

CDC20 was associated with malignant progression of prostate cancer, the patients with both high expression CDC20 and CD44 or β-catenin were associated with more aggressive clinicopathological features and poor prognosis. CDC20 was usually enriched in CD44⁺ prostate CSCs. Knockdown of CDC20 could inhibit the expression of stemness-related genes, self-renewal ability, chemo-resistance, invasion capability and tumorigenicity of CD44⁺ prostate CSCs. Mechanistically, CDC20 promoted degradation of Axin1, the core member of β-catenin destruction complex, sequentially reduced the phosphorylation of β-catenin, promoting the latter into the nucleus, thereby enhancing the self-renewal capacity of CD44⁺ prostate CSCs.

Interpretation

Our results indicated that CDC20 maintains the self-renewal ability of CD44⁺ prostate CSCs by promoting nuclear translocation and trans-activation of β-catenin. In addition, CDC20 combined with CD44 or β-catenin can serve as an important indicator for prognosis of patients with prostate cancer.

Targeting an Autocrine Regulatory Loop in Cancer Stem-like Cells Impairs the Progression and Chemotherapy Resistance of Bladder Cancer

PURPOSE

Cancer stem-like cells (CSCs) contribute to bladder cancer chemotherapy resistance and progression, but the associated mechanisms have not been elucidated. This study determined whether blocking an autocrine signaling loop in CSCs improves the therapeutic effects of cis-platinum on bladder cancer.

EXPERIMENTAL DESIGN

The expression of the epithelial marker OV6 and other markers in human bladder cancer specimens was examined by IHC. The CSC properties of magnetic-activated cell sorting (MACS)-isolated OV6⁺ and OV6^- bladder cancer cells were examined. Molecular mechanisms were assessed through RNA-Seq, cytokine antibody arrays, co-immunoprecipitation (co-IP), chromatin immunoprecipitation (ChIP) and other assays. An orthotopic bladder cancer mouse model was established to evaluate the in vivo effects of a YAP inhibitor (verteporfin) and a PDGFR inhibitor (CP-673451) on the cis-platinum resistance of OV6⁺ CSCs in bladder cancer.

RESULTS

Upregulated OV6 expression positively associated with disease progression and poor prognosis for bladder cancer patients. Compared with OV6^- cells, OV6⁺ bladder cancer cells exhibited strong CSC characteristics, including self-renewal, tumor initiation in NOD/SCID mice, and chemotherapy resistance. YAP, which maintains the stemness of OV6⁺ CSCs, triggered PDGFB transcription by recruiting TEAD1. Autocrine PDGF-BB signaling through its receptor PDGFR stabilized YAP and facilitated YAP nuclear translocation. Furthermore, blocking the YAP/TEAD1/PDGF-BB/PDGFR loop with verteporfin or CP-673451 inhibited the cis-platinum resistance of OV6⁺ bladder cancer CSCs in an orthotopic bladder cancer model.

CONCLUSIONS

OV6 could be a helpful indicator of disease progression and prognosis for patients with bladder cancer, and targeting the autocrine YAP/TEAD1/PDGF-BB/PDGFR loop might serve as a remedy for cis-platinum resistance in patients with advanced bladder cancer.

Cancer Stem Cells or Tumor Survival Cells?

Research endeavors originally generated stem cell definitions for the purpose of describing normally sustainable developmental and tissue turnover processes in various species, including humans. The notion of investigating cells that possess a vague capacity of “stamm (phylum)” can be traced back to the late 19th century, mainly concentrating on cells that could produce the germline or the entire blood system. Lately, such undertakings have been recapitulated for oncogenesis, tumor growth, and cancer cell resistance to oncolytic therapies. However, due to the complexity and basic life-origin mechanisms comprising the genetic and epigenetic repertoire of the stemness in every developing or growing cell, presently there are ongoing debates regarding the biological essentials of the stem cell-like tumor initiation cells (ie, cancer stem cells; CSCs). This conceptual analysis focuses on the potential pitfalls of extrapolating that CSCs bear major traits of stemness. We propose a novel nomenclature of Tumor Survival Cells (TSCs) to further define tumor cells behaving like CSCs, based on the ruthless and detrimental features of Cancer Cell Survivology that appears fundamentally different from stem cell biology. Hence, precise academic separation of TSCs from all the stem cell-related labels applied to these unique tumor cells may help to improve scientific reasoning and strategies to decode the desperado-like survival behaviors of TSCs to eventually overcome cancer.

Screening circular RNA related to chemotherapeutic resistance in breast cancer

Aim: We aimed to identify circular RNAs (circRNAs) associated with breast cancer chemoresistance. Materials & methods: CircRNA microarray expression profiles were obtained from Adriamycin (ADM) resistant MCF-7 breast cancer cells (MCF-7/ADM) and parental MCF-7 cells and were validated using quantitative real-time reverse transcription PCR. The expression data were analyzed bioinformatically. Results: We detected 3093 circRNAs and identified 18 circRNAs that are differentially expressed between MCF-7/ADM and MCF-7 cells; after validating by quantitative real-time reverse transcription PCR, we predicted the possible miRNAs and potential target genes of the seven upregulated circRNAs using TargetScan and miRanda. The bioinformatics analysis revealed several target genes related to cancer-related signaling pathways. Additionally, we discovered a regulatory role of the circ_0006528-miR-7–5p-Raf1 axis in ADM-resistant breast cancer. Conclusion: These results revealed that circRNAs may play a role in breast cancer chemoresistance and that hsa_circ_0006528 might be a promising candidate for further functional analysis.