Function of p21 (Cip1/Waf1/CDKN1A) in Migration and Invasion of Cancer and Trophoblastic Cells

Sorafenib Resistance Contributed by IL7 and MAL2 in Hepatocellular Carcinoma Can Be Overcome by Autophagy-Inducing Stapled Peptides

Drug resistance poses a great challenge in systemic therapy for hepatocellular carcinoma (HCC). However, the underlying molecular mechanisms associated with resistance to anti-cancer drugs, such as Sorafenib, remain unclear. In this study, we use transposon insertional mutagenesis to generate Sorafenib-resistant HCC cell lines in order to identify potential drug resistant causative genes. Interleukin 7 (IL7) and mal, T cell differentiation protein 2 (MAL2) were identified as candidate genes that promote survival by activating JAK/STAT and PI3K/AKT signaling pathways. Sorafenib-resistant cells exhibited higher clonogenic survival and lower drug sensitivity due to IL7 and MAL2 upregulation. Higher anti-apoptotic effect, clonogenic survival and increased PI3K/AKT/STAT3 activities were observed in IL7 and MAL2 co-overexpressing cells compared with controls or cells overexpressing IL7 or MAL2 individually. Given the critical role of MAL2 in endocytosis, we propose that MAL2 might facilitate the endocytic trafficking of IL7 and its cognate receptors to the plasma membrane, which leads to upregulated JAK/STAT and PI3K/AKT signaling pathways and Sorafenib resistance. Additionally, our previous studies showed that an autophagy-inducing stapled peptide promoted the endolysosomal degradation of c-MET oncogene and overcame adaptive Sorafenib resistance in c-MET+ HCC cells. In this study, we demonstrate that these stapled peptides readily induced autophagy and inhibited the proliferation of both wild-type and Sorafenib-resistant HCC cells co-overexpressing both IL7 and MAL2. Furthermore, these peptides showed synergistic cytotoxicity with Sorafenib in drug-resistant HCC cells co-overexpressing both IL7 and MAL2. Our studies suggest that targeting autophagy may be a novel strategy to overcome IL7/MAL2-mediated Sorafenib resistance in HCC.

Trophoblast Differentiation: Mechanisms and Implications for Pregnancy Complications

Placental development is a tightly controlled event, in which cell expansion from the trophectoderm occurs in a spatiotemporal manner. Proper trophoblast differentiation is crucial to the vitality of this gestational organ. Obstructions to its development can lead to pregnancy complications, such as preeclampsia, fetal growth restriction, and preterm birth, posing severe health risks to both the mother and offspring. Currently, the only known treatment strategy for these complications is delivery, making it an important area of research. The aim of this review was to summarize the known information on the development and mechanistic regulation of trophoblast differentiation and highlight the similarities in these processes between the human and mouse placenta. Additionally, the known biomarkers for each cell type were compiled to aid in the analysis of sequencing technologies.

LncRNA NCK1-AS1-mediated regulatory functions in human diseases

Disease development requires the activation of complex multi-factor processes involving numerous long noncoding RNAs (lncRNAs), which describe non-protein-coding RNAs longer than 200 nucleotides. Emerging evidence indicates that lncRNAs act as essential regulators that perform pivotal roles in the pathogenesis and progression of human diseases. The mechanisms underlying lncRNA involvement in diverse diseases have been extensively explored, and lncRNAs are considered powerful biomarkers for clinical practice. The lncRNA noncatalytic region of tyrosine kinase adaptor protein 1 (NCK1) antisense 1 (NCK1-AS1), also known as NCK1 divergent transcript (NCK1-DT), is encoded on human chromosome 3q22.3 and produces a 27,274-base-long transcript. NCK1-AS1 has increasingly been characterized as a causative agent for multiple diseases. The abnormal expression and involvement of NCK1-AS1 in various biological processes have been associated with several diseases. Further exploration of the mechanisms through which NCK1-AS1 contributes to disease development and progression will provide a foundation for potential clinical applications of NCK1-AS1 in the diagnosis and treatment of various diseases. This review summarizes the current understanding of the various functions and mechanisms through which NCK1-AS1 contributes to various diseases and the clinical application prospects for NCK1-AS1.

A promising new cancer marker: Long noncoding RNA EGFR-AS1

Cancer consists of a group of diseases with the salient properties of an uncontrolled cell cycle, metastasis, and evasion of the immune response, mainly driven by the genomic instability of somatic cells and the physicochemical environment. Long noncoding RNAs (lncRNAs) are defined as noncoding RNAs with a length of more than 200 nucleotides. LncRNA dysregulation participates in diverse disease types and is tightly associated with patient clinical features, such as age, disease stage, and prognosis. In addition, an increasing number of lncRNAs have been confirmed to regulate a series of biological and pathological processes through numerous mechanisms. The lncRNA epidermal growth factor receptor antisense RNA 1 (EGFR-AS1) was recently discovered to be aberrantly expressed in many types of diseases, particularly in cancers. A high level of EGFR-AS1 was demonstrated to correlate with multiple patient clinical characteristics. More importantly, EGFR-AS1 was found to be involved in the mediation of various cellular activities, including cell proliferation, invasion, migration, chemosensitivity, and stemness. Therefore, EGFR-AS1 is a promising marker for cancer management. In this review, we introduce the expression profile, molecular mechanisms, biological functions, and clinical value of EGFR-AS1 in cancers.

Elevated histone demethylase KDM5C increases recurrent miscarriage risk by preventing trophoblast proliferation and invasion

KDM5C is a histone H3K4-specific demethylase, which has been shown to play a key role in biological disease and development. However, the role of KDM5C in trophoblasts at early pregnancy is currently unknown. Here, we showed that KDM5C was upregulated in placental trophoblasts from recurrent miscarriage (RM) patients compared with healthy controls (HCs). Trophoblast proliferation and invasion was inhibited by KDM5C overexpression and was promoted by KDM5C knockdown. Transcriptome sequencing revealed that elevated KDM5C exerted anti-proliferation and anti-invasion effects by repressing the expression of essential regulatory genes. The combination analysis of RNA-seq, ChIP-seq and CUT&Tag assay showed that KDM5C overexpression leads to the reduction of H3K4me3 on the promoters and the corresponding downregulation of expression of several regulatory genes in trophoblasts. Among these genes, TGFβ2 and RAGE are essential for the proliferation and invasion of trophoblasts. Importantly, overexpression of KDM5C by a systemically delivered KDM5C adenovirus vector (Ad-KDM5C) promoted embryo resorption rate in mouse. Our results support that KDM5C is an important regulator of the trophoblast function during early pregnancy, and suggesting that KDM5C activity could be responsible for epigenetic alterations seen RM disease.

Downregulation of krüppel-like factor 6 expression modulates extravillous trophoblast cell behavior by increasing reactive oxygen species

INTRODUCTION

Placental extravillous trophoblasts play a crucial role in the establishment of a healthy pregnancy. Reactive oxygen species (ROS) may contribute to their differentiation and function as mediators in signaling processes or might cause oxidative stress resulting in trophoblast dysfunction. The krüppel-like transcription factor 6 (KLF6) regulates many genes involved in essential cell processes where ROS are also involved. However, whether KLF6 regulates ROS levels has not been previously investigated.

MATERIALS AND METHODS

KLF6 was silenced by siRNAs in HTR8-SV/neo cells, an extravillous trophoblast model. Total and mitochondrial ROS levels, as well as mitochondrial membrane potential and apoptosis were analyzed by flow cytometry. The expression of genes and proteins of interest were analyzed by qRT-PCR and Western blot, respectively. Cell response to oxidative stress, proliferation, viability, morphology, and migration were evaluated.

RESULTS

KLF6 downregulation led to an increase in ROS and NOX4 mRNA levels, accompanied by reduced cell proliferation and increased p21 protein expression. Catalase activity, 2-Cys peroxiredoxin protein levels, Nrf2 cytoplasmic localization and hemoxygenase 1 expression, as well as mitochondrial membrane potential and cell apoptosis were not altered suggesting that ROS increase is not associated with cellular damage. Instead, KLF6 silencing induced cytoskeleton modifications and increased cell migration in a ROS-dependent manner.

DISCUSSION

Present data reveal a novel role of KLF6 on ROS balance and signaling demonstrating that KLF6 downregulation induces an increase in ROS levels that contribute to extravillous trophoblast cell migration.

Addiction of Merkel cell carcinoma to MUC1-C identifies a potential new target for treatment

Merkel cell carcinoma (MCC) is an aggressive malignancy with neuroendocrine (NE) features, limited treatment options, and a lack of druggable targets. There is no reported involvement of the MUC1-C oncogenic protein in MCC progression. We show here that MUC1-C is broadly expressed in MCCs and at higher levels in Merkel cell polyomavirus (MCPyV)-positive (MCCP) relative to MCPyV-negative (MCCN) tumors. Our results further demonstrate that MUC1-C is expressed in MCCP, as well as MCCN, cell lines and regulates common sets of signaling pathways related to RNA synthesis, processing, and transport in both subtypes. Mechanistically, MUC1-C (i) interacts with MYCL, which drives MCC progression, (ii) is necessary for expression of the OCT4, SOX2, KLF4, MYC, and NANOG pluripotency factors, and (iii) induces the NEUROD1, BRN2 and ATOH1 NE lineage dictating transcription factors. We show that MUC1-C is also necessary for MCCP and MCCN cell survival by suppressing DNA replication stress, the p53 pathway, and apoptosis. In concert with these results, targeting MUC1-C genetically and pharmacologically inhibits MCC self-renewal capacity and tumorigenicity. These findings demonstrate that MCCP and MCCN cells are addicted to MUC1-C and identify MUC1-C as a potential target for MCC treatment.

Targeting Bone Metastases Signaling Pathway Using Moringa oleifera Seed Nutri-miRs: A Cross Kingdom Approach

Moringa oleifera is a medicinally important plant that has various medical and nutritional uses. Plant miRNAs are a class of non-coding endogenous small RNAs that regulate human-specific mRNA but the mechanistic actions are largely unknown. Here, in this study, we aim to explore the mechanistic action and influence of M. oleifera seed miRNAs on vital human target genes using computer based approaches. The M. oleifera seed miRNAs sequence was taken from published data and identified its human gene targets using a psRNA target analysis server. We identified 94 miRNAs that are able to significantly regulate 47 human target genes, which has enormous biological and functional importance. Out of 47 human targeted genes, 23 genes were found to be associated with PI3K-AKT, RUNX, and MAPK1/MAPK3 signaling pathway which has shown to play key roles in bone metastases during cancer progression. The M. oleifera seed miRNAs hold a strong potential for future research that might uncover the possibility of miRNA-facilitated cross-kingdom regulation and therapeutic targets for bone metastases.

Hey1 promotes migration and invasion of melanoma cells via GRB2/PI3K/AKT signaling cascade

Increasing evidence indicates that Notch signaling regulates multiple intracellular biological processes in malignant melanoma. Whereas how Notch signaling is transduced to influence melanoma cell behaviors remains largely elusive. Here we show that the Notch signaling downstream target Hey1 promotes migration and invasion of melanoma cells via the GRB2/PI3K/AKT pathway. First, bioinformatics tools, immunohistochemistry, and Western blotting analysis showed that the expression of Hey1 is increased in melanoma. Then, both in vivo and in vitro experiments showed that Hey1 promotes the malignant behaviour of the melanoma cells. High-throughput RNA-sequencing analysis revealed that inhibition of Hey1 results in decreased GRB2 expression in melanoma cells. Last, functional experiments confirmed that Hey1 positively regulates GRB2/PI3K/AKT pathway to influence migration and invasion of melanoma cells. In summary, our results suggest that Hey1 promotes the invasion and metastasis of melanoma cells by regulating GRB2/PI3K/AKT pathway. Our study provides potential therapeutics in tumor biology.

Hepatitis B virus x gene-downregulated growth-arrest specific 5 inhibits the cell viability and invasion of hepatocellular carcinoma cell lines by activating Y-box-binding protein 1/p21 signaling

The long noncoding RNA growth-arrest specific 5 (GAS5) is a suppressor of many cancers. However, the role and mechanism of action of GAS5 in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remain unclear. Here, the expression of hepatitis B virus x gene (HBx) mRNA and GAS5 was assessed by qRT-PCR, and western blot analysis was performed to determine the protein expression levels. In addition, the cell viability and invasion of cells were confirmed using  MTT assay and Transwell assay, respectively. The DNA methylation level of GAS5 was measured by methylation-specific PCR. Moreover, RIP assay and RNA pull down assay were carried out to examine the combination of Y-box-binding protein 1 (YBX1) and GAS5. First, our data proved that HBx is increased, while GAS5 is decreased in HCC cell lines. Subsequently, we found that HBx facilitates HCC cell viability and invasion by inhibiting GAS5 expression. Then, we further clarified that HBx induces the DNA methylation of GAS5 by promoting methyltransferase expression, thereby suppressing GAS5 expression. Furthermore, GAS5 binds YBX1 and promotes YBX1 and p21 expression. Finally, the functional analysis revealed that the upregulation of GAS5 could attenuate cell viability and invasion by boosting p21 expression via binding YBX1. Overall, our results demonstrated that HBx promotes HCC progression by inducing GAS5 methylation to reduce its expression. The upregulation of GAS5 suppressed HBV-related HCC by activating YBX1/p21 signaling. Our data provide novel evidence supporting the potential of GAS5 as a treatment target in HBV-related HCC.

Decreased USP2a Expression Inhibits Trophoblast Invasion and Associates With Recurrent Miscarriage

An appropriate development of the placenta consisting of trophoblast cell migration, invasion, proliferation, and apoptosis, is essential to establishing and maintaining a successful pregnancy. Ubiquitin‐specific protease 2a (USP2a) regulates the processes of metastasis in multiple tumor cells. Yet, no known research has focused on exploring the effect of USP2a on trophoblasts and its possible mechanism in the pathogenies of recurrent miscarriage (RM). In this study, we first detected the decreased mRNA levels and the protein levels of USP2a in placental villous tissue samples from the RM patients. In vitro assays verified that overexpression of USP2a promoted human trophoblast proliferation, migration, invasion, whereas knockdown of USP2a inhibited these processes. Mechanistically, USP2a activated PI3K/Akt/GSK3β signaling pathway to promote nuclear translocation of β‐catenin and further activated epithelial-mesenchymal transition (EMT) in the trophoblasts. Moreover, transforming growth factor-beta (TGF-β) up-regulated USP2a expression in trophoblasts. Interestingly, M2 macrophage secreted TGF-β induced trophoblast migration and invasion, and an anti-TGF-β antibody alleviated this effect. Collectively, this study indicated that USP2a regulated trophoblast invasion and that abnormal USP2a expression might lead to aberrant trophoblast invasion, thus contributing to RM.

Functional Analysis of p21Cip1/CDKN1A and Its Family Members in Trophoblastic Cells of the Placenta and Its Roles in Preeclampsia

Preeclampsia (PE), a gestational hypertensive disease originating from the placenta, is characterized by an imbalance of various cellular processes. The cell cycle regulator p21^Cip1/CDKN1A (p21) and its family members p27 and p57 regulate signaling pathways fundamental to placental development. The aim of the present study was to enlighten the individual roles of these cell cycle regulators in placental development and their molecular involvement in the pathogenesis of PE. The expression and localization of p21, phospho-p21 (Thr-145), p27, and p57 was immunohistochemically analyzed in placental tissues from patients with early-onset PE, early-onset PE complicated by the HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome as well as late-onset PE compared to their corresponding control tissues from well-matched women undergoing caesarean sections. The gene level was evaluated using real-time quantitative PCR. We demonstrate that the delivery mode strongly influenced placental gene expression, especially for CDKN1A (p21) and CDKN1B (p27), which were significantly upregulated in response to labor. Cell cycle regulators were highly expressed in first trimester placentas and impacted by hypoxic conditions. In support of these observations, p21 protein was abundant in trophoblast organoids and hypoxia reduced its gene expression. Microarray analysis of the trophoblastic BeWo cell line depleted of p21 revealed various interesting candidate genes and signaling pathways for the fusion process. The level of p21 was reduced in fusing cytotrophoblasts in early-onset PE placentas and depletion of p21 led to reduced expression of fusion-related genes such as syncytin-2 and human chorionic gonadotropin (β-hCG), which adversely affected the fusion capability of trophoblastic cells. These data highlight that cell cycle regulators are important for the development of the placenta. Interfering with p21 influences multiple pathways related to the pathogenesis of PE.

The novel roles of virus infection-associated gene CDKN1A in chemoresistance and immune infiltration of glioblastoma

Chemoresistance is a common limitation for successful treatment of glioblastoma multiforme (GBM). Recently, virus infections have been demonstrated to be associated with tumorigenesis and chemoresistance in tumors. However, the role of infection-related genes in GBM haven’t been clearly demonstrated. Here, we explored the roles and mechanisms of human T-lymphotropic virus type-1 (HTLV-1) infections in tumorigenesis and chemoresistance in GBM. Four candidate genes, CDKN1A, MSX1, MYC and CHEK2, were identified to be the codifferentially expressed genes between three temozolomide (TMZ) chemotherapy datasets and one HTLV-1 infection gene set. Next, comprehensive bioinformatics data from several databases indicated that only CDKN1A was significantly upregulated in both GBM tissues and cells and showed the greatest prognostic value in GBM patients. Clinical data identified the correlations between CDKN1A expression and clinicopathological parameters of GBM patients. Moreover, CDKN1A was found to be involved in AKT-mediated TMZ resistance of glioma cells. In addition, KEGG analysis of CDKN1A-associated coexpression genes showed that CDKN1A was potentially involved in complement and coagulation cascades pathways in GBM. Finally, TISIDB database was used to investigate the role of CDKN1A in tumor-immune system interactions in GBM. These findings enhanced our understanding of the roles of CDKN1A in tumorigenesis and therapy response in GBM.

BCLAF1 induces cisplatin resistance in lung cancer cells

Treatment for non-small cell lung cancer (NSCLC) remains challenging due to frequent recurrence and the development of resistance to platinum-based chemotherapy. The mechanism underlying NSCLC chemoresistance remains unclear. The present study aimed to investigate the mechanism of cisplatin resistance in NSCLC cells and it found that the expression of Bcl-2-associated transcription factor 1 (BCLAF1) was higher in the A549 cell line with cisplatin resistance (A549/DDP) by western blotting and reverse-transcription quantitative PCR, suggesting that elevated BCLAF1 expression is associated with acquired cisplatin resistance in A549 cells. BCLAF1 was found to promote DNA damage repair in A549/DDP cells by regulating γH2A histone family member X foci formation by immunofluorescence and western blotting. BCLAF1 was also demonstrated to regulate ubiquitin-specific peptidase 22 mRNA expression in A549/DDP cells, in addition to regulating G₁ phase arrest by targeting p21 expression. Taken together, these findings suggest that BCLAF1 mediates cisplatin resistance by regulating the repair of DNA damage and p21-mediated G₁ phase arrest.

RITA Is Expressed in Trophoblastic Cells and Is Involved in Differentiation Processes of the Placenta

Preeclampsia (PE) remains a leading cause of maternal and perinatal mortality and morbidity worldwide. Its pathogenesis has not been fully elucidated and no causal therapy is currently available. It is of clinical relevance to decipher novel molecular biomarkers. RITA (RBP-J (recombination signal binding protein J)-interacting and tubulin-associated protein) has been identified as a negative modulator of the Notch pathway and as a microtubule-associated protein important for cell migration and invasion. In the present work, we have systematically studied RITA’s expression in primary placental tissues from patients with early- and late-onset PE as well as in various trophoblastic cell lines. RITA is expressed in primary placental tissues throughout gestation, especially in proliferative villous cytotrophoblasts, in the terminally differentiated syncytiotrophoblast, and in migrating extravillous trophoblasts. RITA’s messenger RNA (mRNA) level is decreased in primary tissue samples from early-onset PE patients. The deficiency of RITA impairs the motility and invasion capacity of trophoblastic cell lines, and compromises the fusion ability of trophoblast-derived choriocarcinoma cells. These data suggest that RITA may play important roles in the development of the placenta and possibly in the pathogenesis of PE.

Novel Epigenetic Biomarkers in Pregnancy-Related Disorders and Cancers

As the majority of cancers and gestational diseases are prognostically stage- and grade-dependent, the ultimate goal of ongoing studies in precision medicine is to provide early and timely diagnosis of such disorders. These studies have enabled the development of various new diagnostic biomarkers, such as free circulating nucleic acids, and detection of their epigenetic changes. Recently, extracellular vesicles including exosomes, microvesicles, oncosomes, and apoptotic bodies have been recognized as powerful diagnostic tools. Extracellular vesicles carry specific proteins, lipids, DNAs, mRNAs, and miRNAs of the cells that produced them, thus reflecting the function of these cells. It is believed that exosomes, in particular, may be the optimal biomarkers of pathological pregnancies and cancers, especially those that are frequently diagnosed at an advanced stage, such as ovarian cancer. In the present review, we survey and critically appraise novel epigenetic biomarkers related to free circulating nucleic acids and extracellular vesicles, focusing especially on their status in trophoblasts (pregnancy) and neoplastic cells (cancers).

RITA modulates cell migration and invasion by affecting focal adhesion dynamics

RITA, the RBP-J interacting and tubulin-associated protein, has been reported to be related to tumor development, but the underlying mechanisms are not understood. Since RITA interacts with tubulin and coats microtubules of the cytoskeleton, we hypothesized that it is involved in cell motility. We show here that depletion of RITA reduces cell migration and invasion of diverse cancer cell lines and mouse embryonic fibroblasts. Cells depleted of RITA display stable focal adhesions (FA) with elevated active integrin, phosphorylated focal adhesion kinase, and paxillin. This is accompanied by enlarged size and disturbed turnover of FA. These cells also demonstrate increased polymerized tubulin. Interestingly, RITA is precipitated with the lipoma-preferred partner (LPP), which is critical in actin cytoskeleton remodeling and cell migration. Suppression of RITA results in reduced LPP and α-actinin at FA leading to compromised focal adhesion turnover and actin dynamics. This study identifies RITA as a novel crucial player in cell migration and invasion by affecting the turnover of FA through its interference with the dynamics of actin filaments and microtubules. Its deregulation may contribute to malignant progression.

The Multifaceted p21 (Cip1/Waf1/CDKN1A) in Cell Differentiation, Migration and Cancer Therapy

Loss of cell cycle control is characteristic of tumorigenesis. The protein p21 is the founding member of cyclin-dependent kinase inhibitors and an important versatile cell cycle protein. p21 is transcriptionally controlled by p53 and p53-independent pathways. Its expression is increased in response to various intra- and extracellular stimuli to arrest the cell cycle ensuring genomic stability. Apart from its roles in cell cycle regulation including mitosis, p21 is involved in differentiation, cell migration, cytoskeletal dynamics, apoptosis, transcription, DNA repair, reprogramming of induced pluripotent stem cells, autophagy and the onset of senescence. p21 acts either as a tumor suppressor or as an oncogene depending largely on the cellular context, its subcellular localization and posttranslational modifications. In the present review, we briefly mention the general functions of p21 and summarize its roles in differentiation, migration and invasion in detail. Finally, regarding its dual role as tumor suppressor and oncogene, we highlight the potential, difficulties and risks of using p21 as a biomarker as well as a therapeutic target.