HIF-3α Promotes Metastatic Phenotypes in Pancreatic Cancer by Transcriptional Regulation of the RhoC-ROCK1 Signaling Pathway

Progression of m6A in the tumor microenvironment: hypoxia, immune and metabolic reprogramming

Recently, N6-methyladenosine (m6A) has aroused widespread discussion in the scientific community as a mode of RNA modification. m6A comprises writers, erasers, and readers, which regulates RNA production, nuclear export, and translation and is very important for human health. A large number of studies have found that the regulation of m6A is closely related to the occurrence and invasion of tumors, while the homeostasis and function of the tumor microenvironment (TME) determine the occurrence and development of tumors to some extent. TME is composed of a variety of immune cells (T cells, B cells, etc.) and nonimmune cells (tumor-associated mesenchymal stem cells (TA-MSCs), cancer-associated fibroblasts (CAFs), etc.). Current studies suggest that m6A is involved in regulating the function of various cells in the TME, thereby affecting tumor progression. In this manuscript, we present the composition of m6A and TME, the relationship between m6A methylation and characteristic changes in TME, the role of m6A methylation in TME, and potential therapeutic strategies to provide new perspectives for better treatment of tumors in clinical work.

ROCK1 regulates glycolysis in pancreatic cancer via the c-MYC/PFKFB3 pathway

BACKGROUND

Dysregulation of Rho-associated coiled coil-containing protein kinases (ROCKs) is involved in the metastasis and progression of various malignant tumors. However, how one of the isomers, ROCK1, regulates glycolysis in tumor cells is incompletely understood. Here, we attempted to elucidate how ROCK1 influences pancreatic cancer (PC) progression by regulating glycolytic activity.

METHODS

The biological function of ROCK1 was analyzed in vitro by establishing a silenced cell model. Coimmunoprecipitation confirmed the direct binding between ROCK1 and c-MYC, and a luciferase reporter assay revealed the binding of c-MYC to the promoter of the PFKFB3 gene. These results were verified in animal experiments.

RESULTS

ROCK1 was highly expressed in PC tissues and enriched in the cytoplasm, and its high expression was associated with a poor prognosis. Silencing ROCK1 inhibited the proliferation and migration of PC cells and promoted their apoptosis. Mechanistically, ROCK1 directly interacted with c-MYC, promoted its phosphorylation (Ser 62) and suppressed its degradation, thereby increasing the transcription of the key glycolysis regulatory factor PFKFB3, enhancing glycolytic activity and promoting PC growth. Silencing ROCK1 increased gemcitabine (GEM) sensitivity in vivo and in vitro.

CONCLUSIONS

ROCK1 promotes glycolytic activity in PC cells and promotes PC tumor growth through the c-MYC/PFKFB3 signaling pathway. ROCK1 knockdown can inhibit PC tumor growth in vivo and increase the GEM sensitivity of PC tumors, providing a crucial clinical therapeutic strategy for PC.

Regulation of Cancer-Associated miRNAs Expression under Hypoxic Conditions

Solid tumors frequently experience hypoxia or low O2 levels. In these conditions, hypoxia-inducible factor 1 alpha (HIF-1α) is activated and acts as a transcription factor that regulates cancer cell adaptation to O2 and nutrient deprivation. HIF-1α controls gene expression associated with various signaling pathways that promote cancer cell proliferation and survival. MicroRNAs (miRNAs) are 22-nucleotide noncoding RNAs that play a role in various biological processes essential for cancer progression. This review presents an overview of how hypoxia regulates the expression of multiple miRNAs in the progression of cancer cells.

Role of long noncoding RNAs in pathological cardiac remodeling after myocardial infarction: An emerging insight into molecular mechanisms and therapeutic potential

Myocardial infarction (MI) is the leading cause of heart failure (HF), accounting for high mortality and morbidity worldwide. As a consequence of ischemia/reperfusion injury during MI, multiple cellular processes such as oxidative stress-induced damage, cardiomyocyte death, and inflammatory responses occur. In the next stage, the proliferation and activation of cardiac fibroblasts results in myocardial fibrosis and HF progression. Therefore, developing a novel therapeutic strategy is urgently warranted to restrict the progression of pathological cardiac remodeling. Recently, targeting long non-coding RNAs (lncRNAs) provided a novel insight into treating several disorders. In this regard, numerous investigations have indicated that several lncRNAs could participate in the pathogenesis of MI-induced cardiac remodeling, suggesting their potential therapeutic applications. In this review, we summarized lncRNAs displayed in the pathophysiology of cardiac remodeling after MI, emphasizing molecular mechanisms. Also, we highlighted the possible translational role of lncRNAs as therapeutic targets for this condition and discussed the potential role of exosomes in delivering the lncRNAs involved in post-MI cardiac remodeling.

Tumour response to hypoxia: understanding the hypoxic tumour microenvironment to improve treatment outcome in solid tumours

Hypoxia is a common feature of solid tumours affecting their biology and response to therapy. One of the main transcription factors activated by hypoxia is hypoxia-inducible factor (HIF), which regulates the expression of genes involved in various aspects of tumourigenesis including proliferative capacity, angiogenesis, immune evasion, metabolic reprogramming, extracellular matrix (ECM) remodelling, and cell migration. This can negatively impact patient outcomes by inducing therapeutic resistance. The importance of hypoxia is clearly demonstrated by continued research into finding clinically relevant hypoxia biomarkers, and hypoxia-targeting therapies. One of the problems is the lack of clinically applicable methods of hypoxia detection, and lack of standardisation. Additionally, a lot of the methods of detecting hypoxia do not take into consideration the complexity of the hypoxic tumour microenvironment (TME). Therefore, this needs further elucidation as approximately 50% of solid tumours are hypoxic. The ECM is important component of the hypoxic TME, and is developed by both cancer associated fibroblasts (CAFs) and tumour cells. However, it is important to distinguish the different roles to develop both biomarkers and novel compounds. Fibronectin (FN), collagen (COL) and hyaluronic acid (HA) are important components of the ECM that create ECM fibres. These fibres are crosslinked by specific enzymes including lysyl oxidase (LOX) which regulates the stiffness of tumours and induces fibrosis. This is partially regulated by HIFs. The review highlights the importance of understanding the role of matrix stiffness in different solid tumours as current data shows contradictory results on the impact on therapeutic resistance. The review also indicates that further research is needed into identifying different CAF subtypes and their exact roles; with some showing pro-tumorigenic capacity and others having anti-tumorigenic roles. This has made it difficult to fully elucidate the role of CAFs within the TME. However, it is clear that this is an important area of research that requires unravelling as current strategies to target CAFs have resulted in worsened prognosis. The role of immune cells within the tumour microenvironment is also discussed as hypoxia has been associated with modulating immune cells to create an anti-tumorigenic environment. Which has led to the development of immunotherapies including PD-L1. These hypoxia-induced changes can confer resistance to conventional therapies, such as chemotherapy, radiotherapy, and immunotherapy. This review summarizes the current knowledge on the impact of hypoxia on the TME and its implications for therapy resistance. It also discusses the potential of hypoxia biomarkers as prognostic and predictive indictors of treatment response, as well as the challenges and opportunities of targeting hypoxia in clinical trials.

Protein kinase B/AKT phosphorylates hypoxia-inducible factor-3α1 in response to insulin, promoting cell growth and migration

Hypoxia-inducible factors (HIFs) are best known for their roles in the adaptation to low oxygen environments. Besides hypoxia, HIF-1/2 α-subunits are also regulated by various non-hypoxic stimuli including insulin which can act via the PI3K/protein kinase B (PKB) signaling pathway. However, with respect to insulin little is known about HIF-3α. We aimed to investigate this relationship and found that insulin stimulates HIF-3α expression under both normal and low oxygen conditions. Blocking PKB activity reversed the effects of insulin, indicating that HIF-3α is a direct target of PKB. We identified serine 524, located in the oxygen-dependent degradation domain of HIF-3α, as a phosphorylation site of PKB. Mutating serine 524 impaired binding of PKB to HIF-3α and its ubiquitination, suggesting that PKB regulates HIF-3α stability through phosphorylation, thereby affecting important cellular processes such as cell viability and cell adhesion. Importantly, we discovered that this phosphorylation site also influenced insulin-dependent cell migration. These findings shed light on a novel mechanism by which insulin affects PKB-dependent HIF-3α expression and activity, with potential implications in metabolic diseases and cancer.

Proteomic and Phosphoproteomic Reprogramming in Epithelial Ovarian Cancer Metastasis

Epithelial ovarian cancer (EOC) is a high-risk cancer presenting with heterogeneous tumors. The high incidence of EOC metastasis from primary tumors to nearby tissues and organs is a major driver of EOC lethality. We used cellular models of spheroid formation and readherence to investigate cellular signaling dynamics in each step toward EOC metastasis. In our system, adherent cells model primary tumors, spheroid formation represents the initiation of metastatic spread, and readherent spheroid cells represent secondary tumors. Proteomic and phosphoproteomic analyses show that spheroid cells are hypoxic and show markers for cell cycle arrest. Aurora kinase B abundance and downstream substrate phosphorylation are significantly reduced in spheroids and readherent cells, explaining their cell cycle arrest phenotype. The proteome of readherent cells is most similar to spheroids, yet greater changes in the phosphoproteome show that spheroid cells stimulate Rho-associated kinase 1 (ROCK1)-mediated signaling, which controls cytoskeletal organization. In spheroids, we found significant phosphorylation of ROCK1 substrates that were reduced in both adherent and readherent cells. Application of the ROCK1-specific inhibitor Y-27632 to spheroids increased the rate of readherence and altered spheroid density. The data suggest ROCK1 inhibition increases EOC metastatic potential. We identified novel pathways controlled by Aurora kinase B and ROCK1 as major drivers of metastatic behavior in EOC cells. Our data show that phosphoproteomic reprogramming precedes proteomic changes that characterize spheroid readherence in EOC metastasis.

Tumor microenvironment-induced tumor cell plasticity: relationship with hypoxic stress and impact on tumor resistance

The role of tumor interaction with stromal components during carcinogenesis is crucial for the design of efficient cancer treatment approaches. It is widely admitted that tumor hypoxic stress is associated with tumor aggressiveness and thus impacts susceptibility and resistance to different types of treatments. Notable biological processes that hypoxia functions in include its regulation of tumor heterogeneity and plasticity. While hypoxia has been reported as a major player in tumor survival and dissemination regulation, the significance of hypoxia inducible factors in cancer stem cell development remains poorly understood. Several reports indicate that the emergence of cancer stem cells in addition to their phenotype and function within a hypoxic tumor microenvironment impacts cancer progression. In this respect, evidence showed that cancer stem cells are key elements of intratumoral heterogeneity and more importantly are responsible for tumor relapse and escape to treatments. This paper briefly reviews our current knowledge of the interaction between tumor hypoxic stress and its role in stemness acquisition and maintenance. Our review extensively covers the influence of hypoxia on the formation and maintenance of cancer stem cells and discusses the potential of targeting hypoxia-induced alterations in the expression and function of the so far known stem cell markers in cancer therapy approaches. We believe that a better and integrated understanding of the effect of hypoxia on stemness during carcinogenesis might lead to new strategies for exploiting hypoxia-associated pathways and their targeting in the clinical setting in order to overcome resistance mechanisms. More importantly, at the present time, efforts are oriented towards the design of innovative therapeutical approaches that specifically target cancer stem cells.

A Step Toward Personalized Surgical Decision Making: Machine Learning Predicts 1 Versus Numerous Melanoma Lymph Node Metastases Using RNA-sequencing

OBJECTIVE

Develop a predictive model to identify patients with 1 pathologic lymph node (pLN) versus >1 pLN using machine learning applied to gene expression profiles and clinical data as input variables.

BACKGROUND

Standard management for clinically detected melanoma lymph node metastases is complete therapeutic LN dissection (TLND). However, >40% of patients with a clinically detected melanoma lymph node will only have 1 pLN on final review. Recent data suggest that targeted excision of just the single enlarged LN may provide excellent regional control, with less morbidity than TLND. The selection of patients for less morbid surgery requires accurate identification of those with only 1 pLN.

METHODS

The Cancer Genome Atlas database was used to identify patients who underwent TLND for melanoma. Pathology reports in The Cancer Genome Atlas were reviewed to identify the number of pLNs. Patients were included for machine learning analyses if RNA sequencing data were available from a pLN. After feature selection, the top 20 gene expression and clinical input features were used to train a ridge logistic regression model to predict patients with 1 pLN versus >1 pLN using 10-fold cross-validation on 80% of samples. The model was then tested on the remaining holdout samples.

RESULTS

A total of 153 patients met inclusion criteria: 64 with one pLN (42%) and 89 with >1 pLNs (58%). Feature selection identified 1 clinical (extranodal extension) and 19 gene expression variables used to predict patients with 1 pLN versus >1 pLN. The ridge logistic regression model identified patient groups with an accuracy of 90% and an area under the receiver operating characteristic curve of 0.97.

CONCLUSIONS

Gene expression profiles together with clinical variables can distinguish melanoma metastasis patients with 1 pLN versus >1 pLN. Future models trained using positron emission tomography/computed tomography imaging, gene expression, and relevant clinical variables may further improve accuracy and may predict patients who can be managed with a targeted LN excision rather than a complete TLND.

Origin and functional diversification of PAS domain, a ubiquitous intracellular sensor

Signal perception is a key function in regulating biological activities and adapting to changing environments. Per-Arnt-Sim (PAS) domains are ubiquitous sensors found in diverse receptors in bacteria, archaea, and eukaryotes, but their origins, distribution across the tree of life, and extent of their functional diversity are not fully characterized. Here, we show that using sequence conservation and structural information, it is possible to propose specific and potential functions for a large portion of nearly 3 million PAS domains. Our analysis suggests that PAS domains originated in bacteria and were horizontally transferred to archaea and eukaryotes. We reveal that gas sensing via a heme cofactor evolved independently in several lineages, whereas redox and light sensing via flavin adenine dinucleotide and flavin mononucleotide cofactors have the same origin. The close relatedness of human PAS domains to those in bacteria provides an opportunity for drug design by exploring potential natural ligands and cofactors for bacterial homologs.

Review of possible mechanisms of radiotherapy resistance in cervical cancer

Radiotherapy is one of the main treatments for cervical cancer. Early cervical cancer is usually considered postoperative radiotherapy alone. Radiotherapy combined with cisplatin is the standard treatment for locally advanced cervical cancer (LACC), but sometimes the disease will relapse within a short time after the end of treatment. Tumor recurrence is usually related to the inherent radiation resistance of the tumor, mainly involving cell proliferation, apoptosis, DNA repair, tumor microenvironment, tumor metabolism, and stem cells. In the past few decades, the mechanism of radiotherapy resistance of cervical cancer has been extensively studied, but due to its complex process, the specific mechanism of radiotherapy resistance of cervical cancer is still not fully understood. In this review, we discuss the current status of radiotherapy resistance in cervical cancer and the possible mechanisms of radiotherapy resistance, and provide favorable therapeutic targets for improving radiotherapy sensitivity. In conclusion, this article describes the importance of understanding the pathway and target of radioresistance for cervical cancer to promote the development of effective radiotherapy sensitizers.

The Role of Reprogrammed Glucose Metabolism in Cancer

Cancer cells reprogram their metabolism to meet biosynthetic needs and to adapt to various microenvironments. Accelerated glycolysis offers proliferative benefits for malignant cells by generating glycolytic products that move into branched pathways to synthesize proteins, fatty acids, nucleotides, and lipids. Notably, reprogrammed glucose metabolism and its associated events support the hallmark features of cancer such as sustained cell proliferation, hijacked apoptosis, invasion, metastasis, and angiogenesis. Overproduced enzymes involved in the committed steps of glycolysis (hexokinase, phosphofructokinase-1, and pyruvate kinase) are promising pharmacological targets for cancer therapeutics. In this review, we summarize the role of reprogrammed glucose metabolism in cancer cells and how it can be manipulated for anti-cancer strategies.

HIF-3α-Induced miR-630 Expression Promotes Cancer Hallmarks in Cervical Cancer Cells by Forming a Positive Feedback Loop

Purpose. Hypoxia has crucial functions in the development and metastasis of cervical cancer by inducing the expression of numerous genes, including microRNA genes. But we know little about how the hypoxia factors and microRNAs orchestrate to regulate hallmarks of cervical cancer cells. Methods. We conducted RNA sequencing (RNA-seq) and chromatin immunoprecipitation sequencing (ChIP-seq) experiments to investigate the targets of HIF-3α or miR-630. ChIP-qPCR and RT-qPCR were carried out to validate the results of ChIP-seq and RNA-seq. Cellular, molecular, and radiation experiments were conducted to explore the functions of miR-630. Results. In this study, we showed that hypoxia-induced overexpression of HIF-3α increased the expression of dozens of miRNAs, including miR-630. Hypoxia could also directly induce miR-630 expression. ChIP-seq data showed that HIF-3α activates miR-630 expression by directly binding to the promoter of its host gene. Meanwhile, stable overexpression of miR-630 increased the expression of HIF-3α, but repressed the expression of HIF-1α, indicating a positive feedback loop between HIF-3α and miR-630. Consequently, stable overexpression of miR-630 in HeLa cells promotes cancer hallmarks, including radioresistance, inhibition of apoptosis, increased migration and invasion, and EMT-mediated metastasis. Meanwhile, inhibition of miR-630 showed opposite features. Conclusion. Taken together, our findings indicate a novel hypoxia-induced HIF-3α and miR-630 regulatory feedback loop contributing to metastasis and progression of cervical cancer cells and suggest that HIF-3α and miR-630 might act as potential biomarkers and therapeutic targets for cervical cancer in the future.

Molecular basis and clinical implications of HIFs in cardiovascular diseases

Oxygen maintains the homeostasis of an organism in a delicate balance in different tissues and organs. Under hypoxic conditions, hypoxia-inducible factors (HIFs) are specific and dominant factors in the spatiotemporal regulation of oxygen homeostasis. As the most basic functional unit of the heart at the cellular level, the cardiomyocyte relies on oxygen and nutrients delivered by the microvasculature to keep the heart functioning properly. Under hypoxic stress, HIFs are involved in acute and chronic myocardial pathology because of their spatiotemporal specificity, thus granting them therapeutic potential. Most adult animals lack the ability to regenerate their myocardium entirely following injury, and complete regeneration has long been a goal of clinical treatment for heart failure. The precise manipulation of HIFs (considering their dynamic balance and transformation) and the development of HIF-targeted drugs is therefore an extremely attractive cardioprotective therapy for protecting against myocardial ischemic and hypoxic injury, avoiding myocardial remodeling and heart failure, and promoting recovery of cardiac function.

Induced pluripotent stem cells display a distinct set of MHC I-associated peptides shared by human cancers

Previous reports showed that mouse vaccination with pluripotent stem cells (PSCs) induces durable anti-tumor immune responses via T cell recognition of some elusive oncofetal epitopes. We characterize the MHC I-associated peptide (MAP) repertoire of human induced PSCs (iPSCs) using proteogenomics. Our analyses reveal a set of 46 pluripotency-associated MAPs (paMAPs) absent from the transcriptome of normal tissues and adult stem cells but expressed in PSCs and multiple adult cancers. These paMAPs derive from coding and allegedly non-coding (48%) transcripts involved in pluripotency maintenance, and their expression in The Cancer Genome Atlas samples correlates with source gene hypomethylation and genomic aberrations common across cancer types. We find that several of these paMAPs were immunogenic. However, paMAP expression in tumors coincides with activation of pathways instrumental in immune evasion (WNT, TGF-β, and CDK4/6). We propose that currently available inhibitors of these pathways could synergize with immune targeting of paMAPs for the treatment of poorly differentiated cancers.

Hypoxia-driven metabolic heterogeneity and immune evasive behaviour of gastrointestinal cancers: Elements of a recipe for disaster

Gastrointestinal (GI) cancers refer to a group of malignancies associated with the GI tract (GIT). Like other solid tumors, hypoxic regions consistently feature inside the GI tumor microenvironment (TME) and contribute towards metabolic reprogramming of tumor-resident cells by modulating hypoxia-induced factors. We highlight here how the metabolic crosstalk between cancer cells and immune cells generate immunosuppressive environment inside hypoxic tumors. Given the fluctuating nature of tumor hypoxia, the metabolic fluxes between immune cells and cancer cells change dynamically. These changes alter cellular phenotypes and functions, resulting in the acceleration of cancer progression. These evolved properties of hypoxic tumors make metabolism-targeting monotherapy approaches or immunotherapy-measures unsuccessful. The current review highlights the advantages of combined immunometabolic treatment strategies to target hypoxic GI cancers and also identifies research areas to develop better combinational therapeutics for future.

Identification of oleoylethanolamide as an endogenous ligand for HIF-3α

Hypoxia-inducible factors (HIFs) are α/β heterodimeric transcription factors modulating cellular responses to the low oxygen condition. Among three HIF-α isoforms, HIF-3α is the least studied to date. Here we show that oleoylethanolamide (OEA), a physiological lipid known to regulate food intake and metabolism, binds selectively to HIF-3α. Through crystallographic analysis of HIF-3 α/β heterodimer in both apo and OEA-bound forms, hydrogen-deuterium exchange mass spectrometry (HDX-MS), molecular dynamics (MD) simulations, and biochemical and cell-based assays, we unveil the molecular mechanism of OEA entry and binding to the PAS-B pocket of HIF-3α, and show that it leads to enhanced heterodimer stability and functional modulation of HIF-3. The identification of HIF-3α as a selective lipid sensor is consistent with recent human genetic findings linking HIF-3α with obesity, and demonstrates that endogenous metabolites can directly interact with HIF-α proteins to modulate their activities, potentially as a regulatory mechanism supplementary to the well-known oxygen-dependent HIF-α hydroxylation.

Long noncoding RNA LINC00857 promotes pancreatic cancer proliferation and metastasis by regulating the miR-130b/RHOA axis

Dysregulation of long noncoding RNAs (lncRNAs) is involved in the pathogenesis and progression of pancreatic cancer (PC). In the current study, we investigated the role and molecular mechanism of LINC00857 in PC. The expression of LINC00857 in PC was analyzed by bioinformatics analysis and qRT-PCR, and the relationship between LINC00857 expression and clinical characteristics of patients of PC was analyzed by Fisher's exact test. Gain- and loss-of-function assays were performed to determine the biological function of LINC00857 in PC. The relationship between LINC00857, miR-130b, and RHOA were determined by RNA pull-down assay, luciferase assay, and qRT-PCR. Our results demonstrated that LINC00857 expression was elevated in PC, and high expression of LINC00857 was positively associated with tumor diameter, T stage, and lymph node metastasis. LINC00857 promoted the proliferation and mobility of PC cells in vitro and in vivo. Mechanistically, LINC00857 acts as a sponge for miR-130b and decreases its expression. miR-130b exhibits tumor suppressor functions in PC, and RHOA was identified as the key target gene of miR-130b. The functions induced by LINC00857 in PC cells were dependent on the miR-130b/RHOA axis. In conclusion, the current study indicated that LINC00857 promotes PC tumorigenesis and metastasis by modulating the miR-130b/RHOA axis, implying that LINC00857 might be a new therapeutic target for PC.

Hypoxia inducible factor-3α promotes osteosarcoma progression by activating KDM3A-mediated demethylation of SOX9

Hypoxia/oxygen-sensing signally is closely associated with many tumor progressions, including osteosarcoma (OS). Previous research principally focused on the function of hypoxia-inducible factor (HIF)-1α and HIF-2α as the major hypoxia-associated transcription factors in OS, however, the role of HIF-3α has not been investigated. Our study found that HIF-3α was upregulated in OS tissues and cell lines. HIF-3α overexpression facilitated cell proliferation and invasion, and inhibited apoptosis, whereas HIF-3α knockdown showed the opposite results. Chromatin immunoprecipitation analysis revealed that lysine demethylase 3A (KDM3A) expression was transcriptionally activated by HIF-3α under hypoxia, and KDM3A occupied the SRY-box transcription factor 9 (SOX9) gene promoter region through H3 lysine 9 dimethylation (H3K9me2). Additionally, rescue results revealed that KDM3A or SOX9 overexpression reversed the effects of HIF-3α silence on cell functions. The Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway inhibitor cucurbitacin I suppressed the promotive effects of HIF-3α overexpression on cell proliferation, invasion and TAK2/STAT3 pathway. Finally, OS cell line MG-63 transfected with HIF-3α short hairpin RNA (HIF-3α shRNA) were subcutaneously injected into nude mice, and the results found that HIF-3α knockdown significantly inhibited the xenograft tumor growth of OS in vivo. In conclusion, this study reveals that HIF-3α promotes OS progression in vitro and in vivo by activating KDM3A-mediated SOX9 promoter demethylation, which may provide a potential therapeutic mechanism for OS.

Ropivacaine Retards the Viability, Migration, and Invasion of Choriocarcinoma Cells by Regulating the Long Noncoding RNA OGFRP1/MicroRNA-4731-5p/HIF3A Axis

Choriocarcinoma is an aggressive gestational trophoblastic neoplasm. This study attempted to explore the biological functions and underlying mechanisms by which ropivacaine restrains the progression of choriocarcinoma. The expression of long noncoding RNA OGFRP1, microRNA-4731-5p (miR-4731-5p), and HIF3A in choriocarcinoma cells was assessed by qRT-PCR. Choriocarcinoma cells treated with ropivacaine at the concentration of 100, 500, and 1000 μM were cultured for 24, 48, and 72 h, respectively. Choriocarcinoma cell viability was evaluated by MTT assay. Transwell assay was conducted to examine choriocarcinoma cell migration and invasion. Additionally, the target relationship between OGFRP1 and miR-4731-5p or between miR-4731-5p and HIF3A was predicted by bioinformatics analysis and confirmed by dual-luciferase reporter assays. OGFRP1 and HIF3A expression were enhanced in choriocarcinoma cells, while miR-4731-5p expression was inhibited. Treatment with ropivacaine impeded choriocarcinoma cell viability, migration, and invasion. Choriocarcinoma cells treated with 1000 μM ropivacaine for 48 h were selected for subsequent experiments. OGFRP1 elevation or miR-4731-5p deficiency mitigated the reduction effect of ropivacaine on tumorigenesis of choriocarcinoma cells. Besides, miR-4731-5p was predicted as the potential OGFRP1 target by StarBase and LncBase, and HIF3A was predicted as the potential miR-4731-5p target by StarBase and TargetScan. Dual-luciferase reporter assays determined that miR-4731-5p was a target of OGFRP1 and HIF3A was a target of miR-4731-5p. Feedback experiments declared that miR-4731-5p elevation or HIF3A suppression reversed the promoting effect of OGFRP1 overexpression on the malignant behaviors of ropivacaine-treated choriocarcinoma cells. Ropivacaine constrained choriocarcinoma cell viability, migration, and invasion through modulating the OGFRP1/miR-4731-5p/HIF3A axis. Our study may provide a novel strategy for choriocarcinoma prevention and treatment.

Role of RhoC in cancer cell migration

Migration is one of the five major behaviors of cells. Although RhoC—a classic member of the Rho gene family—was first identified in 1985, functional RhoC data have only been widely reported in recent years. Cell migration involves highly complex signaling mechanisms, in which RhoC plays an essential role. Cell migration regulated by RhoC—of which the most well-known function is its role in cancer metastasis—has been widely reported in breast, gastric, colon, bladder, prostate, lung, pancreatic, liver, and other cancers. Our review describes the role of RhoC in various types of cell migration. The classic two-dimensional cell migration cycle constitutes cell polarization, adhesion regulation, cell contraction and tail retraction, most of which are modulated by RhoC. In the three-dimensional cell migration model, amoeboid migration is the most classic and well-studied model. Here, RhoC modulates the formation of membrane vesicles by regulating myosin II, thereby affecting the rate and persistence of amoeba-like migration. To the best of our knowledge, this review is the first to describe the role of RhoC in all cell migration processes. We believe that understanding the detail of RhoC-regulated migration processes will help us better comprehend the mechanism of cancer metastasis. This will contribute to the study of anti-metastatic treatment approaches, aiding in the identification of new intervention targets for therapeutic or genetic transformational purposes.

Metabolic reprogramming due to hypoxia in pancreatic cancer: Implications for tumor formation, immunity, and more

Hypoxia is a common phenomenon in most malignant tumors, especially in pancreatic cancer (PC). Hypoxia is the result of unlimited tumor growth and plays an active role in promoting tumor survival, progression, and invasion. As the part of the hypoxia microenvironment in PC is gradually clarified, hypoxia is becoming a key determinant and an important therapeutic target of pancreatic cancer. To adapt to the severe hypoxia environment, cells have changed their metabolic phenotypes to maintain their survival and proliferation. Enhanced glycolysis is the most prominent feature of cancer cells' metabolic reprogramming in response to hypoxia. It provides the energy source for hypoxic cancer cells (although it provides less than oxidative phosphorylation) and produces metabolites that can be absorbed and utilized by normoxic cancer cells. In addition, the uptake of glutamine and fatty acids by hypoxic cancer cells is also increased, which is also conducive to tumor progression. Their metabolites are pooled in the hexosamine biosynthesis pathway (HBP). As a nutrition sensor, HBP, in turn, can coordinate glucose and glutamine metabolism. Its end product, UDP-GlcNAc, is the substrate of protein post-translational modification (PTM) involved in various signaling pathways supporting tumor progression. Adaptive metabolic changes of cancer cells promote their survival and affect tumor immune cells in the tumor microenvironment (TME), which contributes to tumor immunosuppressive microenvironment and induces tumor immunotherapy resistance. Here, we summarize the hypoxic microenvironment, its effect on metabolic reprogramming, and its contribution to immunotherapy resistance in pancreatic cancer.

Dysregulation of Transcription Factor Networks Unveils Different Pathways in Human Papillomavirus 16-Positive Squamous Cell Carcinoma and Adenocarcinoma of the Uterine Cervix

Squamous cell carcinoma (SCC) and adenocarcinoma (ADC) are the most common histological types of cervical cancer (CC). The worse prognosis of ADC cases highlights the need for better molecular characterization regarding differences between these CC types. RNA-Seq analysis of seven SCC and three ADC human papillomavirus 16-positive samples and the comparison with public data from non-tumoral human papillomavirus-negative cervical tissue samples revealed pathways exclusive to each histological type, such as the epithelial maintenance in SCC and the maturity-onset diabetes of the young (MODY) pathway in ADC. The transcriptional regulatory network analysis of cervical SCC samples unveiled a set of six transcription factor (TF) genes with the potential to positively regulate long non-coding RNA genes DSG1-AS1, CALML3-AS1, IGFL2-AS1, and TINCR. Additional analysis revealed a set of MODY TFs regulated in the sequence predicted to be repressed by miR-96-5p or miR-28-3p in ADC. These microRNAs were previously described to target LINC02381, which was predicted to be positively regulated by two MODY TFs upregulated in cervical ADC. Therefore, we hypothesize LINC02381 might act by decreasing the levels of miR-96-5p and miR-28-3p, promoting the MODY activation in cervical ADC. The novel TF networks here described should be explored for the development of more efficient diagnostic tools.

YEATS2 is a target of HIF1α and promotes pancreatic cancer cell proliferation and migration

Hypoxia is involved in the development of pancreatic cancer (PC). The responses of hypoxia-associated genes and their regulated mechanisms are largely unknown. In this study, through bioinformatic analysis and quantitative real-time polymerase chain reaction, the YEATS domain containing 2 (YEATS2) was determined to be a key hypoxia-associated gene. It was increased in PC cells under hypoxia, upregulated in PC tissues, and predicted poor outcome. YEATS2 inhibition decreased the proliferation and migration of PC cells under both normoxia and hypoxia in vitro as well as proliferation and metastasis in vivo. We found that hypoxia-inducible factor 1α (HIF1α) regulated the expression of YEATS2 via binding to the hypoxia response element (HRE) of YEATS2 and coexpressed with YEATS2 in PC tissues. Overexpression of YEATS2 blocked the inhibitory effects of HIF1α silence on PC cell proliferation and migration under hypoxia. Collectively, our study revealed that YEATS2 is a target gene of HIF1α and promotes PC development under hypoxia.

Knockdown of MALAT1 Inhibits the Progression of Chronic Periodontitis via Targeting miR-769-5p/HIF3A Axis

Purpose

Chronic periodontitis (CP) is a long-lasting inflammatory disease that seriously affects oral health. This study is aimed at investigating the regulatory mechanism of metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) in CP.

Methods

Primary human periodontal ligament cells (PDLCs) were treated with P. gingivalis lipopolysaccharide (LPS) to establish a CP model. Quantitative real-time PCR (qRT-PCR) was used to measure the expression of MALAT1 and miR-769-5p in gingival tissues of patients with CP and LPS-treated PDLCs. Cell viability was detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) assay. Enzyme-linked immunosorbent assay (ELISA) was used to measure the levels of inflammatory cytokines. The protein levels of caspase-3, Bax, Bcl-2, and hypoxia-inducible factor (HIF) 3A were determined by western blot assay. Dual-luciferase reporter (DLR) assay was applied to validate the target relationships between miR-769-5p and MALAT1/HIF3A.

Results

The expression of MALAT1 and HIF3A was enhanced, and the expression of miR-769-5p was reduced in gingival tissues of patients with CP and LPS-treated PDLCs. MALAT1 knockdown promoted cell viability and inhibited inflammation and cell apoptosis in LPS-treated PDLCs. MALAT1 targeted miR-769-5p and negatively regulated miR-769-5p expression. miR-769-5p overexpression promoted cell viability and inhibited inflammation and cell apoptosis in LPS-treated PDLCs. Besides, miR-769-5p targeted HIF3A and negatively modulated HIF3A expression. Both miR-769-5p inhibition and HIF3A overexpression reversed the inhibitory effects of MALAT1 silencing on LPS-induced PDLC injury in vitro.

Conclusion

MALAT1 knockdown attenuated LPS-induced PDLC injury via regulating the miR-769-5p/HIF3A axis, which may supply a new target for CP treatment.

Targeting hypoxic tumor microenvironment in pancreatic cancer

Attributable to its late diagnosis, early metastasis, and poor prognosis, pancreatic cancer remains one of the most lethal diseases worldwide. Unlike other solid tumors, pancreatic cancer harbors ample stromal cells and abundant extracellular matrix but lacks vascularization, resulting in persistent and severe hypoxia within the tumor. Hypoxic microenvironment has extensive effects on biological behaviors or malignant phenotypes of pancreatic cancer, including metabolic reprogramming, cancer stemness, invasion and metastasis, and pathological angiogenesis, which synergistically contribute to development and therapeutic resistance of pancreatic cancer. Through various mechanisms including but not confined to maintenance of redox homeostasis, activation of autophagy, epigenetic regulation, and those induced by hypoxia-inducible factors, intratumoral hypoxia drives the above biological processes in pancreatic cancer. Recognizing the pivotal roles of hypoxia in pancreatic cancer progression and therapies, hypoxia-based antitumoral strategies have been continuously developed over the recent years, some of which have been applied in clinical trials to evaluate their efficacy and safety in combinatory therapies for patients with pancreatic cancer. In this review, we discuss the molecular mechanisms underlying hypoxia-induced aggressive and therapeutically resistant phenotypes in both pancreatic cancerous and stromal cells. Additionally, we focus more on innovative therapies targeting the tumor hypoxic microenvironment itself, which hold great potential to overcome the resistance to chemotherapy and radiotherapy and to enhance antitumor efficacy and reduce toxicity to normal tissues.

Ways into Understanding HIF Inhibition

Simple Summary

Cancer cells adapt to hypoxia, survive, and grow. To that aim, they engage hypoxia-inducible pathways. These pathways are under intense investigation in search of new therapies to interfere with signaling components to kill cancer cells. Nowadays, new technologies enable more in-depth studies of hypoxia-induced signaling including protein–protein interaction and transcriptional processes, as well as the mode of action of different inhibitors. In this review, we give insight into useful techniques for studying the components of the hypoxia-inducible pathway and current inhibitors.

Abstract

Hypoxia is a key characteristic of tumor tissue. Cancer cells adapt to low oxygen by activating hypoxia-inducible factors (HIFs), ensuring their survival and continued growth despite this hostile environment. Therefore, the inhibition of HIFs and their target genes is a promising and emerging field of cancer research. Several drug candidates target protein–protein interactions or transcription mechanisms of the HIF pathway in order to interfere with activation of this pathway, which is deregulated in a wide range of solid and liquid cancers. Although some inhibitors are already in clinical trials, open questions remain with respect to their modes of action. New imaging technologies using luminescent and fluorescent methods or nanobodies to complement widely used approaches such as chromatin immunoprecipitation may help to answer some of these questions. In this review, we aim to summarize current inhibitor classes targeting the HIF pathway and to provide an overview of in vitro and in vivo techniques that could improve the understanding of inhibitor mechanisms. Unravelling the distinct principles regarding how inhibitors work is an indispensable step for efficient clinical applications and safety of anticancer compounds.

Long noncoding RNA LINC00941 promotes pancreatic cancer progression by competitively binding miR-335-5p to regulate ROCK1-mediated LIMK1/Cofilin-1 signaling

An accumulation of evidence indicates that long noncoding RNAs are involved in the tumorigenesis and progression of pancreatic cancer (PC). In this study, we investigated the functions and molecular mechanism of action of LINC00941 in PC. Quantitative PCR was used to examine the expression of LINC00941 and miR-335-5p in PC tissues and cell lines, and to investigate the correlation between LINC00941 expression and clinicopathological features. Plasmid vectors or lentiviruses were used to manipulate the expression of LINC00941, miR-335-5p, and ROCK1 in PC cell lines. Gain or loss-of-function assays and mechanistic assays were employed to verify the roles of LINC00941, miR-335-5p, and ROCK1 in PC cell growth and metastasis, both in vivo and in vitro. LINC00941 and ROCK1 were found to be highly expressed in PC, while miR-335-5p exhibited low expression. High LINC00941 expression was strongly associated with larger tumor size, lymph node metastasis, and poor prognosis. Functional experiments revealed that LINC00941 silencing significantly suppressed PC cell growth, metastasis and epithelial–mesenchymal transition. LINC00941 functioned as a molecular sponge for miR-335-5p, and a competitive endogenous RNA (ceRNA) for ROCK1, promoting ROCK1 upregulation, and LIMK1/Cofilin-1 pathway activation. Our observations lead us to conclude that LINC00941 functions as an oncogene in PC progression, behaving as a ceRNA for miR-335-5p binding. LINC00941 may therefore have potential utility as a diagnostic and treatment target in this disease.

Zebrafish Hif3α modulates erythropoiesis via regulation of gata1 to facilitate hypoxia tolerance

The hypoxia-inducible factors 1α and 2α (HIF1α and HIF2α) are master regulators of the cellular response to O_2. In addition to HIF1α and HIF2α, HIF3α is another identified member of the HIFα family. Even though the question of whether some HIF3α isoforms have transcriptional activity or repressive activity is still under debate, it is evident that the full length of HIF3α acts as a transcription factor. However, its function in hypoxia signaling is largely unknown. Here, we show that loss of hif3 a in zebrafish reduced hypoxia tolerance. Further assays indicated that erythrocyte number was decreased because red blood cell maturation was impeded by hif3 a disruption. We found that gata1 expression was downregulated in hif3 a null zebrafish, as were several hematopoietic marker genes, including alas2, band3, hbae1, hbae3 and hbbe1 Hif3α recognized the hypoxia response element located in the promoter of gata1 and directly bound to the promoter to transactivate gata1 expression. Our results suggested that hif3 a facilities hypoxia tolerance by modulating erythropoiesis via gata1 regulation.

HIF3A DNA methylation, obesity and weight gain, and breast cancer risk among Mexican American women

OBJECTIVE

In previous epigenome-wide association studies, Hypoxia inducible Factor 3 Alpha Subunit (HIF3A) DNA methylation has been reported to be associated with body mass index (BMI) and weight change. However, none of these studies have included Mexican Americans.

METHODS

In the current study, we assessed levels of HIF3A methylation in 927 Mexican American women identified from Mano-A-Mano, the Mexican American Cohort study.

RESULTS

Significantly higher methylation levels at three CpG sites (position 46801557, 46801642, and 46801699) were observed in obese women compared to non-obese women (P < 0.05). Furthermore, we found that elevated methylation levels at those three CpG sites were associated with significant weight gain (P < 0.05), defined as an increase in BMI by at least one category between the baseline and the follow-up, with a median follow-up time of 39 months. Then, using pre-diagnostic blood DNA samples, we found increased DNA methylation at CpG 46801642 to be associated with a 1.35-fold increased risk of breast cancer (Hazard Ratio (HR) = 1.35, 95% Confidence Interval (CI): 1.02, 3.01), with a median follow-up time of 127 months. Using the Cancer Genome Atlas (TCGA) data, we further found that levels of HIF3A were significantly higher-methylated and down-regulated in breast tumor than in normal tissues (P < 1 × 10¹² for both).

CONCLUSION

Thus, our results provide evidence to support the role of HIF3A in obesity, weight gain, and the development of breast cancer.

Coming in the Air: Hypoxia Meets Epigenetics in Pancreatic Cancer

With a five-year survival rate under 9%, pancreatic ductal adenocarcinoma (PDAC) represents one of the deadliest tumors. Although the treatment options are slightly improving, PDAC is the second leading cause of cancer related death in 2020 in the US. In addition to a pronounced desmoplastic stroma reaction, pancreatic cancer is characterized by one of the lowest levels of oxygen availability within the tumor mass and these hypoxic conditions are known to contribute to tumor development and progression. In this context, the major hypoxia associated transcription factor family, HIF, regulates hundreds of genes involved in angiogenesis, metabolism, migration, invasion, immune escape and therapy resistance. Current research implications show, that hypoxia also modulates diverse areas of epigenetic mechanisms like non-coding RNAs, histone modifications or DNA methylation, which cooperate with the hypoxia-induced transcription factors as well as directly regulate the hypoxic response pathways. In this review, we will focus on hypoxia-mediated epigenetic alterations and their impact on pancreatic cancer.

Berberine improves insulin resistance in adipocyte models by regulating the methylation of hypoxia-inducible factor-3α

Methylation of hypoxia-inducible factor-3α (HIF3A) was previously demonstrated to be highly associated with insulin resistance (IR) in patients with gestational diabetes mellitus (GDM). We aimed to study the therapeutic effects of Berberine (BBR) on GDM and the possible mechanisms. The expressions and methylated states of HIF3A in pregnant women with GDM were compared with that in healthy controls. The IR cell models of 3T3-L1 adipocytes was constructed by 1 μmol/l dexamethasone (Dex) and 1 μmol/l insulin (Ins). To evaluate the effects of BBR on IR adipocyte models, cells were subjected to BBR treatment at different concentrations. Transfection of HIF3A siRNA further confirmed the role of HIF3A in the BBR-induced improving effects. Low expression and high methylation of HIF3A gene were frequent in the GDM pregnancies. BBR treatment noticeably increased the glucose usage rates, adiponectin secretion and cell differentiation of IR 3T3-L1 adipocytes. Increased HIF3A expression and decreased methylated state of HIF3A were also found in IR adipocytes. Furthermore, HIF3A silencing not only reversed the effects of BBR on improving insulin sensibility, but also partially abolished the expression alterations of insulin-related genes in IR adipocytes induced by BBR treatment. Our results suggest that BBR improves insulin sensibility in IR adipocyte models, and the improving effects of BBR are possibly realized through the inhibition of HIF3A methylation.

A long hypoxia-inducible factor 3 isoform 2 is a transcription activator that regulates erythropoietin

Hypoxia-inducible factor (HIF), an αβ dimer, is the master regulator of oxygen homeostasis with hundreds of hypoxia-inducible target genes. Three HIF isoforms differing in the oxygen-sensitive α subunit exist in vertebrates. While HIF-1 and HIF-2 are known transcription activators, HIF-3 has been considered a negative regulator of the hypoxia response pathway. However, the human HIF3A mRNA is subject to complex alternative splicing. It was recently shown that the long HIF-3α variants can form αβ dimers that possess transactivation capacity. Here, we show that overexpression of the long HIF-3α2 variant induces the expression of a subset of genes, including the erythropoietin (EPO) gene, while simultaneous downregulation of all HIF-3α variants by siRNA targeting a shared HIF3A region leads to downregulation of EPO and additional genes. EPO mRNA and protein levels correlated with HIF3A silencing and HIF-3α2 overexpression. Chromatin immunoprecipitation analyses showed that HIF-3α2 binding associated with canonical hypoxia response elements in the promoter regions of EPO. Luciferase reporter assays showed that the identified HIF-3α2 chromatin-binding regions were sufficient to promote transcription by all three HIF-α isoforms. Based on these data, HIF-3α2 is a transcription activator that directly regulates EPO expression.

Hypoxia: Friend or Foe for drug delivery in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most lethal solid tumors with an overall five-year survival rate of that has only just reached 10%. The tumor microenvironment of PDAC is characterized by desmoplasia, which consist of dense stroma of fibroblasts and inflammatory cells, resulting in a hypoxic environment due to limited oxygen diffusion through the tumor. Hypoxia contributes to the aggressive tumor biology by promoting tumor progression, malignancy, and promoting resistance to conventional and targeted therapeutic agents. In depth research in the area has identified that hypoxia modulates the tumor biology through hypoxia inducible factors (HIFs), which not only are the key determinant of pancreatic malignancy but also an important target for therapy. In this review, we summarize the recent advances in understanding hypoxia driven phenotypes, which are responsible for the highly aggressive and metastatic characteristics of pancreatic cancer, and how hypoxia can be exploited as a target for drug delivery.

LncRNA SNHG7 promotes cardiac remodeling by upregulating ROCK1 via sponging miR-34-5p

Previous studies have shown that lncRNA small nuclear RNA host gene 7 (lncRNA SNHG7) played an important role in cancer progression. However, the role of lncRNA SNHG7 in cardiac fibrosis is still poorly understood. In this study, the results of quantitative real time polymerase chain reaction (qRT-PCR) analysis showed that lncRNA SNHG7 was over expressed in the infarcted and peri-infarcted area in the left ventricle after MI in mice. Western blot analysis showed that knockdown of SNHG7 decreased the expression of collagen type 1 (Col1)and α-smooth muscle actin (α-SMA). Echocardiographic study suggested that inhibition of SNHG7 improved cardiac function after MI in mice. Luciferase assay indicated SNHG7 could act as a competing endogenous RNA (ceRNA) by sponging miR-34-5p. The MTT cell proliferation assay and 5-ethynyl-2’-deoxyuridine (EdU) labelling assay revealed that co-transfection of SNHG7 and miR-34-5p inhibited cell viability and proliferation of cardiac fibroblasts (CF). All the results indicated that lncRNA SNHG7 could promote cardiac fibrosis via targeting miR-34-5p through acting as a ceRNA in mice after MI. Silencing of SNHG7 could attenuate deposition of collagens and improve cardiac function. miR-34-5p could suppress the fibrogenesis of CF by targeting ROCK1 and abolish SNHG7-induced CF proliferation and fibroblast-to-myofibroblast transition.

RhoB is regulated by hypoxia and modulates metastasis in breast cancer

BACKGROUND

RhoB is a Rho family GTPase that is highly homologous to RhoA and RhoC. RhoA and RhoC have been shown to promote tumor progression in many cancer types; however, a distinct role for RhoB in cancer has not been delineated. Additionally, several well-characterized studies have shown that small GTPases such as RhoA, Rac1, and Cdc42 are induced in vitro under hypoxia, but whether and how hypoxia regulates RhoB in breast cancer remains elusive.

AIMS

To determine whether and how hypoxia regulates RhoB expression and to understand the role of RhoB in breast cancer metastasis.

METHODS

We investigated the effects of hypoxia on the expression and activation of RhoB using real-time quantitative polymerase chain reaction and western blotting. We also examined the significance of both decreased and increased RhoB expression in breast cancer using CRISPR depletion of RhoB or a vector overexpressing RhoB in 3D in vitro migration models and in an in vivo mouse model.

RESULTS

We found that hypoxia significantly upregulated RhoB mRNA and protein expression resulting in increased levels of activated RhoB. Both loss of RhoB and gain of RhoB expression led to reduced migration in a 3D collagen matrix and invasion within a multicellular 3D spheroid. We showed that neither the reduction nor overexpression of RhoB affected tumor growth in vivo. While the loss of RhoB had no effect on metastasis, RhoB overexpression led to decreased metastasis to the lungs, liver, and lymph nodes of mice.

CONCLUSION

Our results suggest that RhoB may have an important role in suppressing breast cancer metastasis.

LINC01342 promotes the progression of ovarian cancer by absorbing microRNA-30c-2-3p to upregulate HIF3A

Ovarian cancer (OC) is a highly prevalent gynecologic malignancy and its mortality is extremely high. Therefore, the development of novel therapeutic approaches for OC is of great significance. In this study, LINC01342 was upregulated in OC tissue in the GSE38666 microarray and in tumor tissue samples collected in our center. The silencing of LINC01342 suppressed the proliferative and metastatic capacities of A2780 and HO8910 cells. Subcellular distribution assays showed that LINC01342 was mainly enriched in the cytoplasm. Subsequently, the downregulation of microRNA-30c-2-3p was proven to be the target of LINC01342. The silencing of microRNA-30c-2-3p enhanced the clonality and migratory capacity of OC cells. Moreover, the silencing of microRNA-30c-2-3p could reverse the inhibited migration and clonality in OC cells caused by LINC01342 knockdown. In addition, hypoxia-inducible factor 3 subunit α (HIF3A) was proven to be the target gene of microRNA-30c-2-3p, which was upregulated. HIF3A was negatively regulated by microRNA-30c-2-3p but positively regulated by LINC01342 in OC cells. An RNA binding protein immunoprecipitation assay showed that microRNA-30c-2-3p, LINC01342, and HIF3A could bind to argonaute RISC catalytic component 2. The overexpression of HIF3A reversed the inhibited migration and clonality in OC cells with LINC01342 knockdown. By analyzing the follow-up data from the enrolled OC patients, the LINC01342 and HIF3A levels were negatively correlated with prognosis, while the microRNA-30c-2-3p level was positively correlated with the same. In short, the upregulated LINC01342 in OC absorbs microRNA-30c-2-3p to release HIF3A. Thus, upregulated HIF3A expression accelerates the progression of OC.

RhoC: a fascinating journey from a cytoskeletal organizer to a Cancer stem cell therapeutic target

Tumor heterogeneity results in differential response to therapy due to the existence of plastic tumor cells, called cancer stem cells (CSCs), which exhibit the property of resistance to therapy, invasion and metastasis. These cells have a distinct, signaling network active at every stage of progression. It is difficult to envisage that the CSCs will have a unique set of signaling pathways regulating every stage of disease progression. Rather, it would be easier to believe that a single pivotal pathway having significant contribution at every stage, which can further turn on a battery of signaling mechanisms specific to that stage, would be instrumental in regulating the signaling network, enabling easy transition from one state to another. In this context, we discuss the role of RhoC which has contributed to several phenotypes during tumor progression.

RhoC (Ras homolog gene family member C) has been widely reported to regulate actin organization. It has been shown to impact the motility of cancer cells, resultantly affecting invasion and metastasis, and has contributed to carcinoma progression of the breast, pancreas, lung, ovaries and cervix, among several others. The most interesting finding has been its indispensable role in metastasis. Also, it has the ability to modulate various other phenotypes like angiogenesis, motility, invasion, metastasis, and anoikis resistance. These observations suggest that RhoC imparts the plasticity required by tumor cells to exhibit such diverse functions based on microenvironmental cues. This was further confirmed by recent reports which show that it regulates cancer stem cells in breast, ovary and head and neck cancers. Studies also suggest that the inhibition of RhoC results in abolition of advanced tumor phenotypes.

Our review throws light on how RhoC, which is capable of modulating various phenotypes may be the apt core signaling candidate regulating disease progression. Additionally, mice studies show that RhoC is not essential for embryogenesis, giving scope for its development as a possible therapeutic target. This review thus stresses on the need to understand the protein and its functioning in greater detail to enable its development as a stem cell marker and a possible therapeutic target.

Recurrent Germline DLST Mutations in Individuals with Multiple Pheochromocytomas and Paragangliomas

Pheochromocytomas and paragangliomas (PPGLs) provide some of the clearest genetic evidence for the critical role of metabolism in the tumorigenesis process. Approximately 40% of PPGLs are caused by driver germline mutations in 16 known susceptibility genes, and approximately half of these genes encode members of the tricarboxylic acid (TCA) cycle. Taking as a starting point the involvement of the TCA cycle in PPGL development, we aimed to identify unreported mutations that occurred in genes involved in this key metabolic pathway and that could explain the phenotypes of additional individuals who lack mutations in known susceptibility genes. To accomplish this, we applied a targeted sequencing of 37 TCA-cycle-related genes to DNA from 104 PPGL-affected individuals with no mutations in the major known predisposing genes. We also performed omics-based analyses, TCA-related metabolite determination, and 13C5-glutamate labeling assays. We identified five germline variants affecting DLST in eight unrelated individuals (∼7%); all except one were diagnosed with multiple PPGLs. A recurrent variant, c.1121G>A (p.Gly374Glu), found in four of the eight individuals triggered accumulation of 2-hydroxyglutarate, both in tumors and in a heterologous cell-based assay designed to functionally evaluate DLST variants. p.Gly374Glu-DLST tumors exhibited loss of heterozygosity, and their methylation and expression profiles are similar to those of EPAS1-mutated PPGLs; this similarity suggests a link between DLST disruption and pseudohypoxia. Moreover, we found positive DLST immunostaining exclusively in tumors carrying TCA-cycle or EPAS1 mutations. In summary, this study reveals DLST as a PPGL-susceptibility gene and further strengthens the relevance of the TCA cycle in PPGL development.

LAMB3 mediates apoptotic, proliferative, invasive, and metastatic behaviors in pancreatic cancer by regulating the PI3K/Akt signaling pathway

The poor prognosis of patients with pancreatic ductal adenocarcinoma (PDAC) is partially attributed to the invasive and metastatic behavior of this disease. Laminin subunit beta-3 (LAMB3) encodes one of the three subunits of LM-332, an extracellular matrix protein secreted by cultured human keratinocytes. In addition, LAMB3 is involved in the invasive and metastatic abilities of some types of cancer, including colon, pancreas, lung, cervix, stomach, and prostate cancer, but the role and mechanism of LAMB3 in PDAC have not been previously determined. Herein, we tentatively investigated the role of LAMB3 in the malignant biological behavior of PDAC. In this study, we demonstrated that LAMB3 is upregulated in PDAC. Inhibition of LAMB3 abrogated the tumorigenic outcomes of PI3K/Akt signaling pathway activation, including those involving cell cycle arrest, cell apoptosis, proliferation, invasion and migration in vitro, and tumor growth and liver metastasis in vivo. Our results showed that LAMB3 could mediate cell cycle arrest and apoptosis in PDAC cells and alter the proliferative, invasive, and metastatic behaviors of PDAC by regulating the PI3K/Akt signaling pathway. LAMB3 may be a novel therapeutic target for the treatment of PDAC in the future.

Molecular targets regulating invasion and metastasis of pancreatic cancer

Pancreatic cancer is one of the most malignant tumors of the digestive system. Invasion and metastasis are important biological characteristics of pancreatic cancer and contribute greatly to the poor prognosis of the patients. Many lines of evidence have recently revealed that many molecules, genes and proteins regulate the invasion and metastasis of pancreatic cancer cells. Therefore, exploration and a deep understanding of the molecular mechanism accounting for the invasion and metastasis of pancreatic cancer can help find novel pancreatic cancer biomarkers, improve early diagnosis, develop novel and effective treatment strategies, and predict the prognosis. This review summarizes the latest progress in the research of molecular targets for pancreatic cancer and the mechanisms by which they participate in the invasion and metastasis of this aggressive malignancy.

Transcriptional and post-transcriptional regulation of the genes encoding the small GTPases RhoA, RhoB, and RhoC: implications for the pathogenesis of human diseases

Rho GTPases are highly conserved proteins that play critical roles in many cellular processes including actin dynamics, vesicular trafficking, gene transcription, cell-cycle progression, and cell adhesion. The main mode of regulation of Rho GTPases is through guanine nucleotide binding (cycling between an active GTP-bound form and an inactive GDP-bound form), but transcriptional, post-transcriptional, and post-translational modes of Rho regulation have also been described. In the present review, we summarize recent progress on the mechanisms that control the expression of the three members of the Rho-like subfamily (RhoA, RhoB, and RhoC) at the level of gene transcription as well as their post-transcriptional regulation by microRNAs. We also discuss the progress made in deciphering the mechanisms of cross-talk between Rho proteins and the transforming growth factor β signaling pathway and their implications for the pathogenesis of human diseases such as cancer metastasis and fibrosis.

Pro-inflammatory cytokines activate hypoxia-inducible factor 3α via epigenetic changes in mesenchymal stromal/stem cells

Human mesenchymal stromal/stem cells (hMSCs) emerged as a promising therapeutic tool for ischemic disorders, due to their ability to regenerate damaged tissues, promote angiogenesis and reduce inflammation, leading to encouraging, but still limited results. The outcomes in clinical trials exploring hMSC therapy are influenced by low cell retention and survival in affected tissues, partially influenced by lesion's microenvironment, where low oxygen conditions (i.e. hypoxia) and inflammation coexist. Hypoxia and inflammation are pathophysiological stresses, sharing common activators, such as hypoxia-inducible factors (HIFs) and NF-κB. HIF1α and HIF2α respond essentially to hypoxia, activating pathways involved in tissue repair. Little is known about the regulation of HIF3α. Here we investigated the role of HIF3α in vitro and in vivo. Human MSCs expressed HIF3α, differentially regulated by pro-inflammatory cytokines in an oxygen-independent manner, a novel and still uncharacterized mechanism, where NF-κB is critical for its expression. We investigated if epigenetic modifications are involved in HIF3α expression by methylation-specific PCR and histone modifications. Robust hypermethylation of histone H3 was observed across HIF3A locus driven by pro-inflammatory cytokines. Experiments in a murine model of arteriotomy highlighted the activation of Hif3α expression in infiltrated inflammatory cells, suggesting a new role for Hif3α in inflammation in vivo.