A crucial function of PDGF in TGF-beta-mediated cancer progression of hepatocytes

A predicted epithelial-to-mesenchymal transition-associated mRNA/miRNA axis contributes to the progression of diabetic liver disease

Despite public health measures, type 2 diabetes (T2D) is still a significant concern worldwide, given its associated complications, including hepatic alterations. The role of epithelial-to-mesenchymal transition (EMT) in liver fibrosis is well established. However, its effects on the progression of diabetic liver diseases are not well understood. Therefore, this study aims to investigate the mRNA/miRNA axes involved in this process. Bioinformatic analysis revealed new EMT-associated genes (CDH2, ITGB1, COL4A1, COL1A1, TNC, CCN2, and JUN), which showed higher expression in obese T2D and hepatocellular carcinoma (HCC) patients. In addition, six miRNAs (miR-21-5p, miR-26a-5p, miR-34a-5p, miR-106a-5p, miR-320a-3p and miR-424-5p) have been found as potential targets. Among them, miR-26a-5p and miR-424-5p were significantly downregulated in nonalcoholic steatohepatitis (NASH) and HCC (p < 0.05), being considered potential negative regulators of the EMT process. In our hepatic mesenchymal culture model, miR-26a-5p negatively regulated cadherin 2 (also known as N-cadherin, CDH2) and promoted the cadherin 1 (also known as E-cadherin, CDH1) expression. Our results reveal potential molecules involved in liver tumor development. Moreover, we observe that miR-26a-5p impairs EMT in the initial stages of diabetic liver disease by inhibiting CDH2 and could be a valuable target in this pathology.

A critical appreciation of pathway analysis in atherosclerotic disease. Cellular phenotypic plasticity as an illustrative example

The rapid advancements in genome-scale (omics) techniques has created significant opportunities to investigate complex disease mechanisms in tissues and cells. Nevertheless, interpreting -omics data can be challenging, and pathway enrichment analysis is a frequently used method to identify candidate molecular pathways that drive gene expression changes. With a growing number of -omics studies dedicated to atherosclerosis, there has been a significant increase in studies and hypotheses relying on enrichment analysis. This brief review discusses the benefits and limitations of pathway enrichment analysis within atherosclerosis research. We highlight the challenges of identifying complex biological processes, such as cell phenotypic switching, within -omics data. Additionally, we emphasize the need for more comprehensive and curated gene sets that reflect the biological complexity of atherosclerosis. Pathway enrichment analysis is a valuable tool for gaining insights into the molecular mechanisms of atherosclerosis. Nevertheless, it is crucial to remain aware of the intrinsic limitations of this approach. By addressing these weaknesses, enrichment analysis in atherosclerosis can lead to breakthroughs in identifying the mechanisms of disease progresses, the identification of key driver genes, and consequently, advance personalized patient care.

Hepatocellular Carcinoma: Old and Emerging Therapeutic Targets

Liver cancer, predominantly hepatocellular carcinoma (HCC), globally ranks sixth in incidence and third in cancer-related deaths. HCC risk factors include non-viral hepatitis, alcohol abuse, environmental exposures, and genetic factors. No specific genetic alterations are unequivocally linked to HCC tumorigenesis. Current standard therapies include surgical options, systemic chemotherapy, and kinase inhibitors, like sorafenib and regorafenib. Immunotherapy, targeting immune checkpoints, represents a promising avenue. FDA-approved checkpoint inhibitors, such as atezolizumab and pembrolizumab, show efficacy, and combination therapies enhance clinical responses. Despite this, the treatment of hepatocellular carcinoma (HCC) remains a challenge, as the complex tumor ecosystem and the immunosuppressive microenvironment associated with it hamper the efficacy of the available therapeutic approaches. This review explores current and advanced approaches to treat HCC, considering both known and new potential targets, especially derived from proteomic analysis, which is today considered as the most promising approach. Exploring novel strategies, this review discusses antibody drug conjugates (ADCs), chimeric antigen receptor T-cell therapy (CAR-T), and engineered antibodies. It then reports a systematic analysis of the main ligand/receptor pairs and molecular pathways reported to be overexpressed in tumor cells, highlighting their potential and limitations. Finally, it discusses TGFβ, one of the most promising targets of the HCC microenvironment.

IGFBP2 drives epithelial-mesenchymal transition in hepatocellular carcinoma via activating the Wnt/β-catenin pathway

Metastasis has emerged as a major impediment to achieve successful therapeutic outcomes in hepatocellular carcinoma (HCC). Nonetheless, the intricate molecular mechanisms governing the progression of HCC remain elusive. Herein, we present evidence highlighting the influence exerted by insulin-like growth factor-binding protein 2 (IGFBP2) as a potent oncogene driving the malignant phenotype. Our investigation reveals a marked elevation of IGFBP2 expression in primary tumors, concomitant with the presence of mesenchymal biomarkers in HCC. Through in vitro and in vivo experimentation, we demonstrate that the overexpression of IGFBP2 expedites the progression of epithelial-mesenchymal transition (EMT) and facilitates the metastatic potential of HCC cells, chiefly mediated by the Wnt/β-catenin signaling pathway. Notably, knockdown of IGFBP2 significantly decreased the expression of total and nuclear β-catenin, N-cadherin and vimentin in the treatment of the specific activator of Wnt/β-catenin CHIR-99021. Collectively, our findings identify IGFBP2 as a pivotal regulator within the HCC EMT axis, whereby its overexpression confers the distinctly aggressive clinical features characteristic of the disease.

Extracellular vesicles from retinal pigment epithelial cells expressing R345W-Fibulin-3 induce epithelial-mesenchymal transition in recipient cells

We have shown previously that expression of R345W-Fibulin-3 induces epithelial-mesenchymal transition (EMT) in retinal pigment epithelial (RPE) cells. The purpose of the current study was to determine if extracellular vesicles (EVs) derived from RPE cells expressing R345W-Fibulin-3 mutation are sufficient to induce EMT in recipient cells. ARPE-19 cells were infected with luciferase-tagged wild-type (WT)- Fibulin-3 or luciferase-tagged R345W-Fibulin-3 (R345W) using lentiviruses. EVs were isolated from the media by ultracentrifugation or density gradient ultracentrifugation. Transmission electron microscopy and cryogenic electron microscopy were performed to study the morphology of the EVs. The size distribution of EVs were determined by nanoparticle tracking analysis (NTA). EV cargo was analysed using LC-MS/MS based proteomics. EV-associated transforming growth factor beta 1 (TGFβ1) protein was measured by enzyme-linked immunosorbent assay. The capacity of EVs to stimulate RPE migration was evaluated by treating recipient cells with WT- or R345W-EVs. The role of EV-bound TGFβ was determined by pre-incubation of EVs with a pan-TGFβ blocking antibody or IgG control. EM imaging revealed spherical vesicles with two subpopulations of EVs: a group with diameters around 30 nm and a group with diameters over 100 nm, confirmed by NTA analysis. Pathway analysis revealed that members of the sonic hedgehog pathway were less abundant in R345W- EVs, while EMT drivers were enriched. Additionally, R345W-EVs had higher concentrations of TGFβ1 compared to control. Critically, treatment with R345W-EVs was sufficient to increase EMT marker expression, as well as cell migration in recipient cells. This EV-increased cell migration was significantly inhibited by pre-incubation of EVs with pan-TGFβ-neutralising antibody. In conclusion, the expression of R345W-Fibulin-3 alters the size and cargo of EVs, which are sufficient to enhance the rate of cell migration in a TGFβ dependent manner. These results suggest that EV-bound TGFβ plays a critical role in the induction of EMT in RPE cells.

Modelling the Sorafenib-resistant Liver Cancer Microenvironment by Using 3-D Spheroids

Liver cancer is the third leading cause of cancer-related mortality, and hepatocellular carcinoma (HCC) is the most common form of liver cancer, and it usually occurs in the setting of chronic liver disease and cirrhosis. For patients with advanced HCC, systemic treatment is the first choice - however, resistance occurs frequently. Sorafenib was the first tyrosine kinase inhibitor approved for advanced HCC, and resistance to the therapy is a serious concern. When sorafenib therapy fails in a patient, it can be challenging to decide whether they can undergo a second-line therapy, and to determine which therapy they will be able to tolerate. Thus, physiologically relevant in vitro preclinical models are crucial for screening potential therapies, and 3-D tumour spheroids permit studies of tumour pathobiology. In this study, a drug-resistant 3-D tumour spheroid model was developed, based on sorafenib-resistant hepatocellular carcinoma cells, LX2 stellate cells and THP-1 monocytes. Model tumour spheroids that were formed with the sorafenib-resistant cells demonstrated lower diffusion of doxorubicin and exhibited increased resistance to regorafenib. Moreover, in the sorafenib-resistant spheroids, there was increased presence of CD68-positive cells and a reduction in inflammatory marker secretion. The sorafenib-resistant cell line-derived spheroids also showed a higher expression of FGF-19, PDGF-AA and GDF-15, which are known to be involved in malignancies. This multi-cell type spheroid model represents a potentially useful system to test drug candidates in a microenvironment that mimics the drug-resistant tumour microenvironment in HCC.

Nicotinamide N-methyltransferase sustains a core epigenetic program that promotes metastatic colonization in breast cancer

Metastatic colonization of distant organs accounts for over 90% of deaths related to solid cancers, yet the molecular determinants of metastasis remain poorly understood. Here, we unveil a mechanism of colonization in the aggressive basal-like subtype of breast cancer that is driven by the NAD+ metabolic enzyme nicotinamide N-methyltransferase (NNMT). We demonstrate that NNMT imprints a basal genetic program into cancer cells, enhancing their plasticity. In line, NNMT expression is associated with poor clinical outcomes in patients with breast cancer. Accordingly, ablation of NNMT dramatically suppresses metastasis formation in pre-clinical mouse models. Mechanistically, NNMT depletion results in a methyl overflow that increases histone H3K9 trimethylation (H3K9me3) and DNA methylation at the promoters of PR/SET Domain-5 (PRDM5) and extracellular matrix-related genes. PRDM5 emerged in this study as a pro-metastatic gene acting via induction of cancer-cell intrinsic transcription of collagens. Depletion of PRDM5 in tumor cells decreases COL1A1 deposition and impairs metastatic colonization of the lungs. These findings reveal a critical activity of the NNMT-PRDM5-COL1A1 axis for cancer cell plasticity and metastasis in basal-like breast cancer.

New insights about the PDGF/PDGFR signaling pathway as a promising target to develop cancer therapeutic strategies

Numerous cancers express platelet-derived growth factors (PDGFs) and PDGF receptors (PDGFRs). By directly stimulating tumour cells in an autocrine manner or by stimulating tumour stromal cells in a paracrine manner, the platelet-derived growth factor (PDGF)/platelet-derived growth factor receptor (PDGFR) pathway is crucial in the growth and spread of several cancers. To combat hypoxia in the tumour microenvironment, it encourages angiogenesis. A growing body of experimental data shows that PDGFs target malignant cells, vascular cells, and stromal cells to modulate tumour growth, metastasis, and the tumour microenvironment. To combat medication resistance and enhance patient outcomes in cancers, targeting the PDGF/PDGFR pathway is a viable therapeutic approach. There have been reports of anomalies in the PDGF pathway, including the gain of function point mutations, activating chromosomal translocations, or overexpression or amplification of PDGF receptors (PDGFRs). As a result, it has been shown that targeting the PDGF/PDGFR signaling pathway is an effective method for treating cancer. As a result, this study will concentrate on the regulation of the PDGF/PDGFR signaling system, in particular the current methods and inhibitors used in cancer treatment, as well as the associated therapeutic advantages and side effects.

ST3GAL5-catalyzed gangliosides inhibit TGF-β-induced epithelial-mesenchymal transition via TβRI degradation

Epithelial-mesenchymal transition (EMT) is pivotal in the initiation and development of cancer cell metastasis. We observed that the abundance of glycosphingolipids (GSLs), especially ganglioside subtypes, decreased significantly during TGF-β-induced EMT in NMuMG mouse mammary epithelial cells and A549 human lung adenocarcinoma cells. Transcriptional profiling showed that TGF-β/SMAD response genes and EMT signatures were strongly enriched in NMuMG cells, along with depletion of UDP-glucose ceramide glucosyltransferase (UGCG), the enzyme that catalyzes the initial step in GSL biosynthesis. Consistent with this finding, genetic or pharmacological inhibition of UGCG promoted TGF-β signaling and TGF-β-induced EMT. UGCG inhibition promoted A549 cell migration, extravasation in the zebrafish xenograft model, and metastasis in mice. Mechanistically, GSLs inhibited TGF-β signaling by promoting lipid raft localization of the TGF-β type I receptor (TβRI) and by increasing TβRI ubiquitination and degradation. Importantly, we identified ST3GAL5-synthesized a-series gangliosides as the main GSL subtype involved in inhibition of TGF-β signaling and TGF-β-induced EMT in A549 cells. Notably, ST3GAL5 is weakly expressed in lung cancer tissues compared to adjacent nonmalignant tissues, and its expression correlates with good prognosis.

Transforming growth factor-β signaling: from tumor microenvironment to anticancer therapy

Transforming growth factor-β (TGF-β) signaling is an important pathway for promoting the pathogenesis of inflammatory diseases, including cancer. The roles of TGF-β signaling are heterogeneous and versatile in cancer development and progression, both anticancer and protumoral actions are reported. Interestingly, increasing evidence suggests that TGF-β enhances disease progression and drug resistance via immune-modulatory actions in the tumor microenvironment (TME) of solid tumors. A better understanding of its regulatory mechanisms in the TME at the molecular level can facilitate the development of precision medicine to block the protumoral actions of TGF-β in the TME. Here, the latest information about the regulatory mechanisms and translational research of TGF-β signaling in the TME for therapeutic development had been summarized.

Roles of platelets in tumor invasion and metastasis: A review

The invasion and metastasis of malignant tumors are major causes of death. The most common metastases of cancer are lymphatic metastasis and hematogenous metastasis. Hematogenous metastasis often leads to rapid tumor dissemination. The mechanism of hematogenous metastasis of malignant tumors is very complex. Some experts have found that platelets play an important role in promoting tumor hematogenous metastasis. Platelets may be involved in many processes, such as promoting tumor cell survival, helping tumor cells escape immune surveillance, helping tumors attach to endothelial cells and penetrating capillaries for distant metastasis. However, recent studies have shown that platelets can also inhibit tumor metastasis. At present, the function of platelets in tumor progression has been widely studied, and they not only promote tumor cell metastasis, but also have an inhibitory effect. Therefore, in-depth and summary research of the molecular mechanism of platelets in tumor cell metastasis is of great significance for the screening and treatment of cancer patients. The following is a brief review of the role of platelets in the process of malignant tumor metastasis.

The E3 Ligases in Cervical Cancer and Endometrial Cancer

Endometrial (EC) and cervical (CC) cancers are the most prevalent malignancies of the female reproductive system. There is a global trend towards increasing incidence and mortality, with a decreasing age trend. E3 ligases label substrates with ubiquitin to regulate their activity and stability and are involved in various cellular functions. Studies have confirmed abnormal expression or mutations of E3 ligases in EC and CC, indicating their vital roles in the occurrence and progression of EC and CC. This paper provides an overview of the E3 ligases implicated in EC and CC and discusses their underlying mechanism. In addition, this review provides research advances in the target of ubiquitination processes in EC and CC.

Platelets involved tumor cell EMT during circulation: communications and interventions

Distant spreading of metastatic tumor cells is still the leading cause of tumor death. Metastatic spreading is a complex process, in which epithelial-mesenchymal transition (EMT) is the primary and key event to promote it. Presently, extensive reviews have given insights on the occurrence of EMT at the primary tumor site that depends on invasive properties of tumor cells and the tumor-associated microenvironment. However, essential roles of circulation environment involved in tumor cell EMT is not well summarized. As a main constituent of the blood, platelet is increasingly found to work as an important activator to induce EMT. Therefore, this review aims to emphasize the novel role of platelet in EMT through signal communications between platelets and circulation tumor cells, and illustrate potent interventions aiming at their communications. It may give a complementary view of EMT in addition to the tissue microenvironment, help for better understand the hematogenous metastasis, and also illustrate theoretical and practical basis for the targeted inhibition.

Diverse roles of tumor-stromal PDGFB-to-PDGFRβ signaling in breast cancer growth and metastasis

Over the last couple of decades, it has become increasingly apparent that the tumor microenvironment (TME) mediates every step of cancer progression and solid tumors are only able to metastasize with a permissive TME. This intricate interaction of cancer cells with their surrounding TME, or stroma, is becoming more understood with an ever greater knowledge of tumor-stromal signaling pairs such as platelet-derived growth factors (PDGF) and their cognate receptors. We and others have focused our research efforts on understanding how tumor-derived PDGFB activates platelet-derived growth factor receptor beta (PDGFRβ) signaling specifically in the breast cancer TME. In this chapter, we broadly discuss PDGF and PDGFR expression patterns and signaling in normal physiology and breast cancer. We then detail the expansive roles played by the PDGFB-to-PDGFRβ signaling pathway in modulating breast tumor growth and metastasis with a focus on specific cellular populations within the TME, which are responsive to tumor-derived PDGFB. Given the increasingly appreciated importance of PDGFB-to-PDGFRβ signaling in breast cancer progression, specifically in promoting metastasis, we end by discussing how therapeutic targeting of PDGFB-to-PDGFRβ signaling holds great promise for improving current breast cancer treatment strategies.

Mesenchymal and stem-like prostate cancer linked to therapy-induced lineage plasticity and metastasis

Bioinformatic analysis of 94 patient-derived xenografts (PDXs), cell lines, and organoids (PCOs) identifies three intrinsic transcriptional subtypes of metastatic castration-resistant prostate cancer: androgen receptor (AR) pathway + prostate cancer (PC) (ARPC), mesenchymal and stem-like PC (MSPC), and neuroendocrine PC (NEPC). A sizable proportion of castration-resistant and metastatic stage PC (M-CRPC) cases are admixtures of ARPC and MSPC. Analysis of clinical datasets and mechanistic studies indicates that MSPC arises from ARPC as a consequence of therapy-induced lineage plasticity. AR blockade with enzalutamide induces (1) transcriptional silencing of TP53 and hence dedifferentiation to a hybrid epithelial and mesenchymal and stem-like state and (2) inhibition of BMP signaling, which promotes resistance to AR inhibition. Enzalutamide-tolerant LNCaP cells re-enter the cell cycle in response to neuregulin and generate metastasis in mice. Combined inhibition of HER2/3 and AR or mTORC1 exhibits efficacy in models of ARPC and MSPC or MSPC, respectively. These results define MSPC, trace its origin to therapy-induced lineage plasticity, and reveal its sensitivity to HER2/3 inhibition.

Integrative network analysis of early-stage lung adenocarcinoma identifies aurora kinase inhibition as interceptor of invasion and progression

Here we focus on the molecular characterization of clinically significant histological subtypes of early-stage lung adenocarcinoma (esLUAD), which is the most common histological subtype of lung cancer. Within lung adenocarcinoma, histology is heterogeneous and associated with tumor invasion and diverse clinical outcomes. We present a gene signature distinguishing invasive and non-invasive tumors among esLUAD. Using the gene signatures, we estimate an Invasiveness Score that is strongly associated with survival of esLUAD patients in multiple independent cohorts and with the invasiveness phenotype in lung cancer cell lines. Regulatory network analysis identifies aurora kinase as one of master regulators of the gene signature and the perturbation of aurora kinases in vitro and in a murine model of invasive lung adenocarcinoma reduces tumor invasion. Our study reveals aurora kinases as a therapeutic target for treatment of early-stage invasive lung adenocarcinoma.

Canonical TGFβ signaling induces collective invasion in colorectal carcinogenesis through a Snail1- and Zeb1-independent partial EMT

Local invasion is the initial step towards metastasis, the main cause of cancer mortality. In human colorectal cancer (CRC), malignant cells predominantly invade as cohesive collectives and may undergo partial epithelial-mesenchymal transition (pEMT) at the invasive front. How this particular mode of stromal infiltration is generated is unknown. Here we investigated the impact of oncogenic transformation and the microenvironment on tumor cell invasion using genetically engineered organoids as CRC models. We found that inactivation of the Apc tumor suppressor combined with expression of oncogenic Kras^G12D and dominant-negative Trp53^R172H did not cell-autonomously induce invasion in vitro. However, oncogenic transformation primed organoids for activation of a collective invasion program upon exposure to the prototypical microenvironmental factor TGFβ1. Execution of this program co-depended on a permissive extracellular matrix which was further actively remodeled by invading organoids. Although organoids shed some epithelial properties particularly at the invasive edge, TGFβ1-stimulated organoids largely maintained epithelial gene expression while additionally implementing a mesenchymal transcription pattern, resulting in a pEMT phenotype that did not progress to a fully mesenchymal state. Notably, while TGFβ1 induced pEMT and promoted collective invasion, it abrogated self-renewal capacity of TKA organoids which correlated with the downregulation of intestinal stem cell (ISC) marker genes. Mechanistically, induction of the non-progressive pEMT required canonical TGFβ signaling mediated by Smad transcription factors (TFs), whereas the EMT master regulators Snail1 and Zeb1 were dispensable. Gene expression profiling provided further evidence for pEMT of TGFβ1-treated organoids and showed that their transcriptomes resemble those of human poor prognosis CMS4 cancers which likewise exhibit pEMT features. We propose that collective invasion in colorectal carcinogenesis is triggered by microenvironmental stimuli through activation of a novel, transcription-mediated form of non-progressive pEMT independently of classical EMT regulators.

Increased abundance of Cbl E3 ligases alters PDGFR signaling in recessive dystrophic epidermolysis bullosa

In recessive dystrophic epidermolysis bullosa (RDEB), loss of collagen VII, the main component of anchoring fibrils critical for epidermal-dermal cohesion, affects several intracellular signaling pathways and leads to impaired wound healing and fibrosis. In skin fibroblasts, wound healing is also affected by platelet-derived growth factor receptor (PDGFR) signaling. To study a potential effect of loss of collagen VII on PDGFR signaling we performed unbiased disease phosphoproteomics. Whereas RDEB fibroblasts exhibited an overall weaker response to PDGF, Cbl E3 ubiquitin ligases, negative regulators of growth factor signaling, were stronger phosphorylated. This increase in phosphorylation was linked to higher Cbl mRNA and protein levels due to increased TGFβ signaling in RDEB. In turn, increased Cbl levels led to increased PDGFR ubiquitination, internalization, and degradation negatively affecting MAPK and AKT downstream signaling pathways. Thus, our results indicate that elevated TGFβ signaling leads to an attenuated response to growth factors, which contributes to impaired dermal wound healing in RDEB.

Epithelial plasticity, epithelial-mesenchymal transition, and the TGF-β family

Epithelial cells repress epithelial characteristics and elaborate mesenchymal characteristics to migrate to other locations and acquire new properties. Epithelial plasticity responses are directed through cooperation of signaling pathways, with TGF-β and TGF-β-related proteins playing prominent instructive roles. Epithelial-mesenchymal transitions (EMTs) directed by activin-like molecules, bone morphogenetic proteins, or TGF-β regulate metazoan development and wound healing and drive fibrosis and cancer progression. In carcinomas, diverse EMTs enable stem cell generation, anti-cancer drug resistance, genomic instability, and localized immunosuppression. This review discusses roles of TGF-β and TGF-β-related proteins, and underlying molecular mechanisms, in epithelial plasticity in development and wound healing, fibrosis, and cancer.

The TGF-β Pathway: A Pharmacological Target in Hepatocellular Carcinoma?

Transforming Growth Factor-beta (TGF-β) superfamily members are essential for tissue homeostasis and consequently, dysregulation of their signaling pathways contributes to the development of human diseases. In the liver, TGF-β signaling participates in all the stages of disease progression from initial liver injury to hepatocellular carcinoma (HCC). During liver carcinogenesis, TGF-β plays a dual role on the malignant cell, behaving as a suppressor factor at early stages, but contributing to later tumor progression once cells escape from its cytostatic effects. Moreover, TGF-β can modulate the response of the cells forming the tumor microenvironment that may also contribute to HCC progression, and drive immune evasion of cancer cells. Thus, targeting the TGF-β pathway may constitute an effective therapeutic option for HCC treatment. However, it is crucial to identify biomarkers that allow to predict the response of the tumors and appropriately select the patients that could benefit from TGF-β inhibitory therapies. Here we review the functions of TGF-β on HCC malignant and tumor microenvironment cells, and the current strategies targeting TGF-β signaling for cancer therapy. We also summarize the clinical impact of TGF-β inhibitors in HCC patients and provide a perspective on its future use alone or in combinatorial strategies for HCC treatment.

Crenolanib Regulates ERK and AKT/mTOR Signaling Pathways in RAS/BRAF-Mutated Colorectal Cancer Cells and Organoids

Recently developed molecularly targeted therapies such as EGFR inhibitors have notably improved the prognosis of patients with cancer. However, patients with KRAS and BRAF mutations do not currently benefit from these therapies. Here, we aimed to examine potential effects of crenolanib as a new molecularly targeted therapy in colorectal cancer. We used multiple colorectal cancer cell lines to investigate the growth-inhibitory effect of crenolanib and its effect in combination with other cytotoxic agents. Primary cultures of patient-derived organoids (PDO), a model that reflects the heterogeneity of clinical colorectal cancer, were used to further validate the effects of crenolanib. Unlike cetuximab, crenolanib remarkably suppressed ERK and AKT/mTOR pathways in HT29 cells with BRAF mutation and in HCT116 cells with KRAS mutation with corresponding growth-suppressing effects. Additive or synergistic effects were observed in treatments with combination of crenolanib and other cytotoxic drugs. Moreover, crenolanib suppressed the expression of stem cell markers, such as OCT4, NANOG, and SOX2. These observations were substantiated in seven PDOs with KRAS mutation and two PDOs without KRAS/BRAF mutations, with crenolanib suppressing the growth of all PDOs regardless of their KRAS mutation status. Furthermore, crenolanib abrogated PDGF- and TGFβ-induced increase of OCT4-positive cells in PDOs. Together, these findings suggest that crenolanib may have clinical utility for patients with colorectal cancer, especially patients with KRAS/BRAF mutations. IMPLICATIONS: These findings indicate that crenolanib can be a useful target agent for patients with colorectal cancer, especially patients with KRAS/BRAF mutations.

Novel therapeutic compounds for prostate adenocarcinoma treatment: An analysis using bioinformatic approaches and the CMap database

INTRODUCTION

Prostate adenocarcinoma is the most frequently diagnosed malignancy, particularly for people >70 years old. The main challenge in the treatment of advanced neoplasm is bone metastasis and therapeutic resistance for known oncology drugs. Novel treatment methods to prolong the survival time and improve the life quality of these specific patients are required. The present study attempted to screen potential therapeutic compounds for the tumor through bioinformatics approaches, in order to provide conceptual treatment for this malignant disease.

METHODS

Differentially expressed genes were obtained from the Gene Expression Omnibus database and submitted into the Connectivity Map database for the detection of potentially associated compounds. Target genes were extracted from the search results. Functional annotation and pathway enrichment were performed for the confirmation. Survival analysis was used to measure potential therapeutic effects.

RESULTS

It was revealed that 3 compounds (vanoxerine, tolnaftate, and gabexate) may help to prolong the disease-free survival time from tumor metastasis of patients with the tumor. A total of 6 genes [also-keto reductase family 1 member C3 (AKR1C3), collagen type III α 1 chain (COL3A1), lipoprotein lipase (LPL), glucuronidase, β pseudogene 11 (GUSBP11), apolipoprotein E (APOE), and collagen type I α 1 chain (COL1A1)] were identified to be the potential therapeutic targets for the aforementioned compounds.

CONCLUSION

In the present study, it was speculated that 3 compounds may function as the potential therapeutic drugs of bone metastatic prostate adenocarcinoma; however, further studies verifying vitro and in vivo are necessary.

The systemic immune-inflammation index predicts prognosis in intrahepatic cholangiocarcinoma: an international multi-institutional analysis

BACKGROUND

The objective of this study was to examine whether the systemic immune inflammation index (SII) was associated with prognosis among patients following resection of intrahepatic cholangiocarcinoma (ICC).

METHODS

The impact of SII on overall (OS) and cancer-specific survival (CSS) following resection of ICC was assessed. The performance of the final multivariable models that incorporated inflammatory markers (i.e. neutrophil-to-lymphocyte ratio [NLR], platelet-to-lymphocyte ratio [PLR] and SII [platelets∗NLR]) was assessed using the Harrell's concordance index.

RESULTS

Patients with high SII had worse 5-year OS (37.7% vs 46.6%, p < 0.001) and CSS (46.1% vs 50.1%, p < 0.001) compared with patients with low SII. An elevated SII (HR = 1.70, 95% CI 1.23-2.34) and NLR (HR = 1.58, 95% CI 1.10-2.27) independently predicted worse OS, whereas high PLR (HR = 1.17, 95% CI 0.85-1.60) was no longer associated with prognosis. Only SII remained an independent predictor of CSS (HR = 1.55, 95% CI 1.09-2.21). The SII multivariable model outperformed models that incorporated PLR and NLR relative to OS (c-index; 0.696 vs 0.689 vs 0.692) and CSS (c-index; 0.697 vs 0.689 vs 0.690).

CONCLUSION

SII independently predicted OS and CSS among patients with resectable ICC. SII may be a better predictor of outcomes compared with other markers of inflammatory response among patients with resectable ICC.

The dichotomous role of TGF-β in controlling liver cancer cell survival and proliferation

Hepatocellular carcinoma (HCC) is the major form of primary liver cancer and one of the most prevalent and life-threatening malignancies globally. One of the hallmarks in HCC is the sustained cell survival and proliferative signals, which are determined by the balance between oncogenes and tumor suppressors. Transforming growth factor beta (TGF-β) is an effective growth inhibitor of epithelial cells including hepatocytes, through induction of cell cycle arrest, apoptosis, cellular senescence, or autophagy. The antitumorigenic effects of TGF-β are bypassed during liver tumorigenesis via multiple mechanisms. Furthermore, along with malignant progression, TGF-β switches to promote cancer cell survival and proliferation. This dichotomous nature of TGF-β is one of the barriers to therapeutic targeting in liver cancer. Thereafter, understanding the underlying molecular mechanisms is a prerequisite for discovering novel antitumor drugs that may specifically disable the growth-promoting branch of TGF-β signaling or restore its tumor-suppressive arm. This review summarizes how TGF-β inhibits or promotes liver cancer cell survival and proliferation, highlighting the functional switch mechanisms during the process.

Identifying Common Genes Related to Platelet and Immunity for Lung Adenocarcinoma Prognosis Prediction

Background

Although 1000s of immune-related and platelet receptor-related genes have been identified in lung adenocarcinoma, their role in prognosis prediction remains unclear.

Methods

We downloaded mRNA data from the Cancer Genome Atlas Dataset (TCGA), and GSE68465 or GSE14814 data sets from the Gene Expression Omnibus (GEO) database.

Results

The high-risk group’s overall survival (OS) time was lower than that of the low-risk group’s in TCGA (p = 1.15e-03). Additionally, the risk score was an independent prognostic survival factor for lung adenocarcinoma patients in TCGA (HR = 2.136, 95%CI = 1.553–2.937, p < 0.001). The model’s prognostic performance was verified with two independent GEO cohorts (GSE68465 and GSE14814). We also developed a nomogram and provided free webpage prediction tools.¹ The mechanism of the high-risk group in this risk score may be have been related to somatic mutations and copy number changes. In addition, this risk score can distinguish the prognosis of the other two cancers (ACC, p < 0.001 and KIRP, p < 0.001). Also, among the other seven cancers, the OS prognosis for high and low risk groups show wide variation (p < 0.05).

Conclusion

Our research demonstrates that CCNA2 and TGFB2 are potential diagnostic and prognostic biomarkers, as well as therapeutic targets in lung adenocarcinoma (LUAD). We also determined a novel and reliable prognostic score for lung adenocarcinoma prognosis. The online nomogram prediction tool that contains this risk score may also help clinical medical staff.

Long non-coding RNA H19 promotes colorectal cancer metastasis via binding to hnRNPA2B1

Background

Long non-coding RNA H19 was demonstrated to be significantly correlated with tumor metastasis. However, the specific functions of H19 in colorectal cancer (CRC) metastasis and the underlying mechanism are still largely unclear.

Methods

Use public database to screen the potential lncRNA crucial for metastasis in colorectal cancer. The expression of H19 in clinical CRC specimens was detected by qRT-PCR. The effect of H19 on the metastasis of CRC cells was investigated by transwell, wound healing assays, CCK-8 assays and animal studies. The potential proteins binding to H19 were identified by LC-MS and verified by RNA immunoprecipitation (RIP). The expression of indicated RNA and proteins were measured by qRT-PCR or western blot.

Results

We found the expression of lncRNA H19 was significantly upregulated in primary tumor and metastatic tissues, correlated with poor prognosis in CRC. Ectopic H19 expression promoted the metastasis of colorectal cancer cells in vitro and in vivo, and induced epithelial-to-mesenchymal transition (EMT). Mechanistically, H19 directly bound to hnRNPA2B1. Knockdown of hnRNPA2B1 attenuated the H19-induce migration and invasion in CRC cells. Furthermore, H19 stabilized and upregulated the expression of Raf-1 by facilitated the interaction between hnRNPA2B1 and Raf-1 mRNA, resulting in activation of Raf-ERK signaling.

Conclusions

Our findings demonstrate the role of H19/hnRNPA2B1/EMT axis in regulation CRC metastasis, suggested H19 could be a potential biomarker to predict prognosis as well as a therapeutic strategy for CRC.

Role of the RNA-binding protein La in cancer pathobiology

RNA-binding proteins are important regulators of RNA metabolism and are of critical importance in all steps of the gene expression cascade. The role of aberrantly expressed RBPs in human disease is an exciting research field and the potential application of RBPs as a therapeutic target or a diagnostic marker represents a fast-growing area of research.Aberrant overexpression of the human RNA-binding protein La has been found in various cancer entities including lung, cervical, head and neck, and chronic myelogenous leukaemia. Cancer-associated La protein supports tumour-promoting processes such as proliferation, mobility, invasiveness and tumour growth. Moreover, the La protein maintains the survival of cancer cells by supporting an anti-apoptotic state that may cause resistance to chemotherapeutic therapy.The human La protein represents a multifunctional post-translationally modified RNA-binding protein with RNA chaperone activity that promotes processing of non-coding precursor RNAs but also stimulates the translation of selective messenger RNAs encoding tumour-promoting and anti-apoptotic factors. In our model, La facilitates the expression of those factors and helps cancer cells to cope with cellular stress. In contrast to oncogenes, able to initiate tumorigenesis, we postulate that the aberrantly elevated expression of the human La protein contributes to the non-oncogenic addiction of cancer cells. In this review, we summarize the current understanding about the implications of the RNA-binding protein La in cancer progression and therapeutic resistance. The concept of exploiting the RBP La as a cancer drug target will be discussed.

Prognostic role of 14q32.31 miRNA cluster in various carcinomas: a systematic review and meta-analysis

Deregulated miR-379/miR-656 cluster expression is considered as important for carcinogenesis and can be used as a potential prognostic marker. Hence, the meta-analysis was conducted to test the utility of miR-379/miR-656 cluster as a prognostic marker in various cancers. A literature search was performed using Web of Science, PubMed and Cochrane Library to obtain relevant studies and were subjected to various subgroup and bioinformatics analyses. Selected twenty-three studies contained 13 cancer types comprising of 3294 patients from 7 nations. Univariate and multivariate data showed an association of high expression of miRNAs with the poor prognosis of cancer patients (p < 0.001). The subgroup analysis showed that lung cancer, breast cancer and papillary renal cell carcinoma (p < 0.001) have a negative association with the survival of patients. Our study is the first meta-analysis showing the association of miR-379/miR-656 cluster expression and overall survival, suggesting its potential as a prognostic indicator in multiple cancers.

Exploring receptor tyrosine kinases-inhibitors in Cancer treatments

Background

Receptor tyrosine kinases (RTKs) are signaling enzymes responsible for the transfer of Adenosine triphosphate (ATP) γ-phosphate to the tyrosine residues substrates. RTKs demonstrate essential roles in cellular growth, metabolism, differentiation, and motility. Anomalous expression of RTK customarily leads to cell growth dysfunction, which is connected to tumor takeover, angiogenesis, and metastasis. Understanding the structure, mechanisms of adaptive and acquired resistance, optimizing inhibition of RTKs, and eradicating cum minimizing the havocs of quiescence cancer cells is paramount.

MainText

Tyrosine kinase inhibitors (TKIs) vie with RTKs ATP-binding site for ATP and hitherto reduce tyrosine kinase phosphorylation, thus hampering the growth of cancer cells. TKIs can either be monoclonal antibodies that compete for the receptor’s extracellular domain or small molecules that inhibit the tyrosine kinase domain and prevent conformational changes that activate RTKs. Progression of cancer is related to aberrant activation of RTKs due to due to mutation, excessive expression, or autocrine stimulation.

Conclusions

Understanding the modes of inhibition and structures of RTKs is germane to the design of novel and potent TKIs. This review shed light on the structures of tyrosine kinases, receptor tyrosine kinases, tyrosine kinase inhibitors, minimizing imatinib associated toxicities, optimization of tyrosine kinase inhibition in curtailing quiescence in cancer cells and the prospects of receptor tyrosine kinase based treatments.

Inadequate DNA Damage Repair Promotes Mammary Transdifferentiation, Leading to BRCA1 Breast Cancer

Loss of BRCA1 p220 function often results in basal-like breast cancer (BLBC), but the underlying disease mechanism is largely opaque. In mammary epithelial cells (MECs), BRCA1 interacts with multiple proteins, including NUMB and HES1, to form complexes that participate in interstrand crosslink (ICL) DNA repair and MEC differentiation control. Unrepaired ICL damage results in aberrant transdifferentiation to a mesenchymal state of cultured, human basal-like MECs and to a basal/mesenchymal state in primary mouse luminal MECs. Loss of BRCA1, NUMB, or HES1 or chemically induced ICL damage in primary murine luminal MECs results in persistent DNA damage that triggers luminal to basal/mesenchymal transdifferentiation. In vivo single-cell analysis revealed a time-dependent evolution from normal luminal MECs to luminal progenitor-like tumor cells with basal/mesenchymal transdifferentiation during murine BRCA1 BLBC development. Growing DNA damage accompanied this malignant transformation.

An ERG Enhancer-Based Reporter Identifies Leukemia Cells with Elevated Leukemogenic Potential Driven by ERG-USP9X Feed-Forward Regulation

Acute leukemia is a rapidly progressing blood cancer with low survival rates. Unfavorable prognosis is attributed to insufficiently characterized subpopulations of leukemia stem cells (LSC) that drive chemoresistance and leukemia relapse. Here we utilized a genetic reporter that assesses stemness to enrich and functionally characterize LSCs. We observed heterogeneous activity of the ERG+85 enhancer-based fluorescent reporter in human leukemias. Cells with high reporter activity (tagBFP^High) exhibited elevated expression of stemness and chemoresistance genes and demonstrated increased clonogenicity and resistance to chemo- and radiotherapy as compared with their tagBFP^Neg counterparts. The tagBFP^High fraction was capable of regenerating the original cellular heterogeneity and demonstrated increased invasive ability. Moreover, the tagBFP^High fraction was enriched for leukemia-initiating cells in a xenograft assay. We identified the ubiquitin hydrolase USP9X as a novel ERG transcriptional target that sustains ERG+85-positive cells by controlling ERG ubiquitination. Therapeutic targeting of USP9X led to preferential inhibition of the ERG-dependent leukemias. Collectively, these results characterize human leukemia cell functional heterogeneity and suggest that targeting ERG via USP9X inhibition may be a potential treatment strategy in patients with leukemia. SIGNIFICANCE: This study couples a novel experimental tool with state-of-the-art approaches to delineate molecular mechanisms underlying stem cell-related characteristics in leukemia cells.

Neuregulin‑1 impacting bone marrow mesenchymal stem cell migration is conducive to functional recovery following spinal cord injury

The present study was designed to investigate the effect of neuregulin-1 (NRG1) on the migration of rat bone marrow mesenchymal stem cells (BMSCs) and evaluate the role of NRG1 in the functional recovery following spinal cord injury (SCI). Firstly, the effect of NRG1 on the mRNA expression of Snail in the BMSCs was detected by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis; secondly, the BMSCs were transfected with a Snail-overexpression plasmid (pBabe-puro-Snail) and the expression levels of Snail and matrix metalloptoreinase-2 (MMP-2) were detected by RT-qPCR and western blot analyses; thirdly, the cell proliferation and migration of BMSCs modified with pBabe-puro-Snail were detected by methyl thiazolyl tetrazolium and migration assays, respectively; finally, functional recovery of SCI was assessed using the Basso, Beattie, and Bresnahan rating scales. The results showed that NRG1 concentration-dependently promoted the expression of Snail with a peak at 40 ng/ml and 48 h; NRG1 enhanced the promoting effect of Snail on the expression of MMP-2; the overexpression of Snail did not enhance the cell growth of the BMSCs. The NRG1-modified BMSCs promoted the functional recovery of SCI. These results suggested that NRG1 significantly promoted the expression of MMP-2 by upregulating the expression of Snail, and enhanced cell migration of the BMSCs conducive to the functional recovery of SCI.

Multifaceted role of cancer educated platelets in survival of cancer cells

Platelets, the derivatives of megakaryocytes, pose dynamic biological functions such as homeostasis and wound healing. The mechanisms involved in these processes are utilized by cancerous cells for proliferation and metastasis. Platelets through their activation establish an aggregate termed as Tumor cell induced platelet aggregation (TCIPA) that aids in establishing a niche for the primary tumor at secondary site while recruiting granulocytes and monocytes. The study of these close interactions between the tumor and the platelets can be exploited as biomarkers in liquid biopsy for early cancer detection, thereby increasing the life expectancy of cancer patients.

Tyrosine Kinase Inhibitor Imatinib Mesylate Alters DMBA-Induced Early Onco/Suppressor Gene Expression with Tissue-Specificity in Mice

Tyrosine kinases play crucial roles in cellular development and tumorigenesis. Tyrosine kinase inhibitors (TKIs) are effective and widely used drug molecules in targeted cancer therapies. Altered expressions of protooncogenes and tumor suppressor genes after DMBA (7,12-dimethylbenz[a]anthracene) treatment have been described as early markers of tumor induction; however their tissue-specific effects remain still unclear. Our study was aimed at examining the short-term possible antineoplastic and chemopreventive effects of a TKI compound (imatinib mesylate) on a DMBA-induced mouse tumor model. In addition, we also investigated the tissue-specific expressions of Hras, Kras, Myc, and Trp53 genes in the brain, bone marrow, spleen, liver, abdominal lymph nodes, thymus, lungs, and kidneys, respectively. 24 hours after the imatinib mesylate injection, we observed significant Kras downregulation in the bone marrow and lung of the DMBA-treated mice. Moreover, the mRNA expression of Myc was also found to be decreased significantly in the spleen. Interestingly, while Trp53 expression was significantly increased in the lung, it was decreased in the other tissues. However, there was also a tendency in the decreased Myc level in the bone marrow, brain, kidneys, lungs, and lymph nodes and in the decreased Hras level in the bone marrow, kidneys, and lungs, although no significant differences were observed. Our findings indicate rapid tissue-specific impact of imatinib mesylate on DMBA-induced gene expression in vivo, supporting the chemopreventive potential of imatinib mesylate in cancer.

Phage Ligands for Identification of Mesenchymal-Like Breast Cancer Cells and Cancer-Associated Fibroblasts

Epithelial to mesenchymal transition (EMT) is believed to be crucial for primary tumors to escape their original residence and invade and metastasize. To properly define EMT, there is a need for ligands that can identify this phenomenon in tumor tissue and invivo. A phage-display selection screening was performed to select novel binding phage peptides for identification of EMT in breast cancer. Epithelial breast cancer cell line, MCF-7 was transformed to mesenchymal phenotype by TGF-β treatment and was used for selection. Breast fibroblasts were used for subtractive depletion and breast cancer metastatic cell lines MDA-MB-231, T47D-shNMI were used for specificity assay. The binding peptides were identified, and their binding capacities were confirmed by phage capture assay, phage-based ELISA, immunofluorescence microscopy. The phage peptide bearing the 7-amino acid sequence, LGLRGSL, demonstrated selective binding to EMT phenotypic cells (MCF-7/TGF-β and MDA-MB-231) as compared to epithelial subtype, MCF-7, T47D and breast fibroblasts (Hs578T). The selected phage was also able to identify metastatic breast cancer tumor in breast cancer tissue microarray (TMA). These studies suggest that the selected phage peptide LGLRGSL identified by phage-display library, showed significant ability to bind to mesenchymal-like breast cancer cells/ tissues and can serve as a novel probe/ligand for metastatic breast cancer diagnostic and imaging.

The cross-talk between TGF-β and PDGFRα signaling pathways regulates stromal fibro/adipogenic progenitors’ fate

Fibro/adipogenic progenitors (FAPs) are tissue-resident mesenchymal stromal cells (MSCs) required for proper skeletal muscle development, regeneration, and maintenance. However, FAPs are also responsible for fibro-fatty scar deposition following chronic damage. We aimed to study a functional cross-talk between TGF-β and PDGFRα signaling pathways in FAPs’ fate. Here, we show that the number of FAPs correlates with TGF-β levels and with extracellular matrix deposition during regeneration and repair. Interestingly, the expression of PDGFRα changed dynamically in the stromal/fibroblast lineage after injury. Furthermore, PDGFRα-dependent immediate early gene expression changed during regeneration and repair. We also found that TGF-β signaling reduces PDGFRα expression in FAPs, mouse dermal fibroblasts, and in two related mesenchymal/fibroblast cell lines. Moreover, TGF-β promotes myofibroblast differentiation of FAPs but inhibits their adipogenicity. Accordingly, TGF-β impairs the expression of PDGFRα-dependent immediate early genes in a TGF-BR1-dependent manner. Finally, pharmacological inhibition of PDGFRα activity with AG1296 impaired TGF-β-induced extracellular matrix remodeling, Smad2 signaling, myofibroblast differentiation, and migration of MSCs. Thus, our work establishes a functional cross-talk between TGF-β and PDGFRα signaling pathways that is involved in regulating the biology of FAPs/MSCs.

Corneal chemical burn treatment through a delivery system consisting of TGF-β1 siRNA: in vitro and in vivo

Chemical burns are major causes of corneal blindness. Transforming growth factor beta-1 (TGFβ₁) plays an important role in induction of corneal inflammation-related-fibrosis leading to the blindness. Here, a topical delivery system consisting anti-fibrotic TGF-β₁ siRNA, an inflammatory suppressing gene, was designed for treatment of corneal injuries. TGF-β₁ siRNA loaded in nanoparticles (NPs) made up of polyethyleneimine polymer demonstrated high fibroblast transfection efficiency. Moreover, TGF-β₁ and PDGF genes and ECM deposition were suppressed in isolated human corneal fibroblasts. NPs inhibited proliferation and transformation of fibroblasts to myofibroblasts by S-phase arrest and α-SMA suppression in vitro, respectively. The mentioned finding was also confirmed in vivo, addressing high wound-healing potential of prepared gene delivery system which was superior to conventional betamethasone treatment. Besides, CD4⁺ and α-SMA antibody staining showed inhibited angiogenesis and myofibroblast accumulation in treated corneas. This study opens a new way for treating corneal fibrosis through topical siRNA delivery.

Selective deletion of hepatocyte platelet-derived growth factor receptor α and development of liver fibrosis in mice

BACKGROUND

Platelet-derived growth factor receptor α (PDGFRα) expression is increased in activated hepatic stellate cells (HSCs) in cirrhotic liver, while normal hepatocytes express PDGFRα at a negligible level. However, cancerous hepatocytes may show upregulation of PDGFRα, and hepatocellular carcinoma is preceded by chronic liver injury. The role of PDGFRα in non-cancerous hepatocytes and liver fibrosis is unclear. We hypothesized that upon liver injury, PDGFRα in insulted hepatocytes contributes to liver fibrosis by facilitating intercellular crosstalk between hepatocytes and HSCs.

METHODS

Hepatocytes were isolated from normal and thioacetamide (TAA)-induced cirrhotic livers for assessment of PDGFRα expression. Conditional knock-out (KO) C57BL/6 mice, in which PDGFRα was selectively deleted in hepatocytes, were generated. Liver fibrosis was induced by injecting TAA for 8 weeks. Hep3B cells were transfected with a small interfering RNA (siRNA) (PDGFRα or control) and co-cultured with LX2 cells.

RESULTS

PDGFRα expression was increased in hepatocytes from fibrotic livers compared to normal livers. Conditional PDGFRα KO mice had attenuated TAA-induced liver fibrosis with decreased HSC activation and proliferation. Immunoblot analyses revealed decreased expression of phospho-p44/42 MAPK in TAA-treated KO mice; these mice also showed almost complete suppression of the upregulation of mouse double minute 2. Although KO mice exhibited increased expression of transforming growth factor (TGF)-β and Smad2/3, this was compensated for by increased expression of inhibitory Smad7. LX2 cells co-cultured with PDGFRα siRNA-infected Hep3B cells showed decreased PDGFRα, α smooth muscle actin, collagen α1(I), TGFβ, and Smad2/3 expression. LX2/PDGFRα-deleted hepatocyte co-culture medium showed decreased PDGF-BB and PDGF-CC levels.

CONCLUSIONS

Deletion of PDGFRα in hepatocytes attenuated the upregulation of PDGFRα in HSCs after TAA treatment, resulting in decreased liver fibrosis and HSC activation. This suggests that in the event of chronic liver injury, PDGFRα in hepatocytes plays an important role in liver fibrosis by affecting PDGFRα expression in HSCs.

Cross-talk among writers, readers, and erasers of m6A regulates cancer growth and progression

The importance of RNA methylation in biological processes is an emerging focus of investigation. We report that altering m⁶A levels by silencing either N ⁶-adenosine methyltransferase METTL14 (methyltransferase-like 14) or demethylase ALKBH5 (ALKB homolog 5) inhibits cancer growth and invasion. METTL14/ALKBH5 mediate their protumorigenic function by regulating m⁶A levels of key epithelial-mesenchymal transition and angiogenesis-associated transcripts, including transforming growth factor-β signaling pathway genes. Using MeRIP-seq (methylated RNA immunoprecipitation sequencing) analysis and functional studies, we find that these target genes are particularly sensitive to changes in m⁶A modifications, as altered m⁶A status leads to aberrant expression of these genes, resulting in inappropriate cell cycle progression and evasion of apoptosis. Our results reveal that METTL14 and ALKBH5 determine the m⁶A status of target genes by controlling each other's expression and by inhibiting m⁶A reader YTHDF3 (YTH N ⁶-methyladenosine RNA binding protein 3), which blocks RNA demethylase activity. Furthermore, we show that ALKBH5/METTL14 constitute a positive feedback loop with RNA stability factor HuR to regulate the stability of target transcripts. We discover that hypoxia alters the level/activity of writers, erasers, and readers, leading to decreased m⁶A and consequently increased expression of target transcripts in cancer cells. This study unveils a previously undefined role for m⁶A in cancer and shows that the collaboration among writers-erasers-readers sets up the m⁶A threshold to ensure the stability of progrowth/proliferation-specific genes, and protumorigenic stimulus, such as hypoxia, perturbs that m⁶A threshold, leading to uncontrolled expression/activity of those genes, resulting in tumor growth, angiogenesis, and progression.

Blocking MIR155HG/miR-155 axis inhibits mesenchymal transition in glioma

Background

MIR155 host gene (MIR155HG) is a long noncoding RNA that has been considered as the primary micro (mi)RNA of miR-155. MIR155HG plays an essential role in hematopoiesis, inflammation, and tumorigenesis. Our study investigated the clinical significance, biological function, mechanisms, and small-molecule inhibitors of the MIR155HG/miR-155 axis in glioma.

Methods

We analyzed the expression of the MIR155HG/miR-155 axis and the correlation with glioma grade and patient survival using 2 different glioma gene expression datasets. Biological significance was elucidated through a series of in vitro and in vivo experiments. Furthermore, we conducted a high-throughput screening for small molecules to identify a potential inhibitor of the MIR155HG/miR-155 axis.

Results

Increased MIR155HG was associated with glioma grade, mesenchymal transition, and poor prognosis. Functionally, MIR155HG reduction by small interfering RNA inhibited cell proliferation, migration, invasion, and orthotopic glioma growth by repressing the generation of its derivatives miR-155-5p and miR-155-3p. Bioinformatics and luciferase reporter assays revealed that protocadherin 9 and protocadherin 7, which act as tumor suppressors by inhibiting the Wnt/β-catenin pathway, were direct targets of miR-155-5p and miR-155-3p, respectively. Finally, we identified NSC141562 as a potent small-molecule inhibitor of the MIR155HG/miR-155 axis.

Conclusions

Our results demonstrate that the MIR155HG/miR-155 axis plays a critical role in facilitating glioma progression and serves as a prognostic factor for patient survival in glioblastoma. High-throughput screening indicated that the MIR155HG/miR-155 axis inhibitor NSC141562 may be a useful candidate anti-glioma drug.

Platelet-derived growth factor receptor-α and -β promote cancer stem cell phenotypes in sarcomas

Sarcomas are malignant tumors derived from mesenchymal tissues and may harbor a subset of cells with cancer stem-like cell (CSC) properties. Platelet-derived growth factor receptors α and β (PDGFR-α/β) play an important role in the maintenance of mesenchymal stem cells. Here we examine the role of PDGFR-α/β in sarcoma CSCs. PDGFR-α/β activity and the effects of PDGFR-α/β inhibition were examined in 3 human sarcoma cell lines using in vitro assays and mouse xenograft models. In all three cell lines, PDGFR-α/β activity was significantly higher in cells grown as spheroids (to enrich for CSCs) and in cells sorted for CD133 expression (a marker of sarcoma CSCs). Self-renewal transcription factors Nanog, Oct4, and Slug and epithelial-to-mesenchymal transition (EMT) proteins Snail, Slug, and Zeb1 were also significantly higher in spheroids cells and CD133(+) cells. Spheroid cells and CD133(+) cells demonstrated 2.9- to 4.2-fold greater migration and invasion and resistance to doxorubicin chemotherapy. Inhibition of PDGFR-α/β in CSCs using shRNA or pharmacologic inhibitors reduced expression of certain self-renewal and EMT proteins, reduced spheroid formation by 74-82%, reduced migration and invasion by 73-80%, and reversed chemotherapy resistance. In mouse xenograft models, combining PDGFR-α/β inhibition (using shRNA or imatinib) with doxorubicin had a more-than-additive effect in blocking tumor growth, with enhanced apoptosis, especially in CD133(+) cells. These results indicate that PDGFR-α/β activity is upregulated in sarcoma CSCs and promote CSC phenotypes including migration, invasion, and chemotherapy resistance. Thus, the PDGFR-α/β pathway represents a new potential therapeutic target to reduce metastatic potential and increase chemosensitivity.

EMT Subtype Influences Epithelial Plasticity and Mode of Cell Migration

Epithelial-mesenchymal transition (EMT) is strongly implicated in tumor cell invasion and metastasis. EMT is thought to be regulated primarily at the transcriptional level through the repressive activity of EMT transcription factors. However, these classical mechanisms have been parsed out almost exclusively in vitro, leaving questions about the programs driving EMT in physiological contexts. Here, using a lineage-labeled mouse model of pancreatic ductal adenocarcinoma to study EMT in vivo, we found that most tumors lose their epithelial phenotype through an alternative program involving protein internalization rather than transcriptional repression, resulting in a "partial EMT" phenotype. Carcinoma cells utilizing this program migrate as clusters, contrasting with the single-cell migration pattern associated with traditionally defined EMT mechanisms. Moreover, many breast and colorectal cancer cell lines utilize this alternative program to undergo EMT. Collectively, these results suggest that carcinoma cells have different ways of losing their epithelial program, resulting in distinct modes of invasion and dissemination.

Detection of multiple perturbations in multi-omics biological networks

Cellular mechanism-of-action is of fundamental concern in many biological studies. It is of particular interest for identifying the cause of disease and learning the way in which treatments act against disease. However, pinpointing such mechanisms is difficult, due to the fact that small perturbations to the cell can have wide-ranging downstream effects. Given a snapshot of cellular activity, it can be challenging to tell where a disturbance originated. The presence of an ever-greater variety of high-throughput biological data offers an opportunity to examine cellular behavior from multiple angles, but also presents the statistical challenge of how to effectively analyze data from multiple sources. In this setting, we propose a method for mechanism-of-action inference by extending network filtering to multi-attribute data. We first estimate a joint Gaussian graphical model across multiple data types using penalized regression and filter for network effects. We then apply a set of likelihood ratio tests to identify the most likely site of the original perturbation. In addition, we propose a conditional testing procedure to allow for detection of multiple perturbations. We demonstrate this methodology on paired gene expression and methylation data from The Cancer Genome Atlas (TCGA).

Androgen deprivation therapy-induced epithelial-mesenchymal transition of prostate cancer through downregulating SPDEF and activating CCL2

The chemokine CC motif ligand 2 (CCL2) is important in recruiting tumor-associated macrophages and is involved in the development of castration-resistance prostate cancer (CRPC) after androgen-deprivation therapy (ADT); however, the underlying mechanism remains unclear. We found that inactivation of the androgen receptor (AR) reduces a transcriptional repressor (SAM pointed domain-containing ETS transcription factor, SPDEF) of CCL2, which mediates epithelial-to-mesenchymal transition (EMT) of prostate tumor cells. Cell lines derived from a prostate-specific Pten/Trp53-null mouse and capable of a spontaneous EMT were utilized for identification of CCL2, and showed that reduced SPDEF expression was associated with an elevated CCL2-activated EMT. AR signaling inhibits CCL2 through a SPDEF-mediated mechanism in that the SPDEF recognizes the CCL2 promoter and transcriptionally represses its activity. Ectopically expressed SPDEF reduced the EMT and rescued expression of CCL2 in SPDEF-expressing cells, which induced the EMT and promotes malignant functions of prostate cancer cells. In tissues from prostate cancer patients with ADT, low SPDEF levels were correlated with high CCL2 expression compared to patients without ADT. We present a novel mechanism that contributes to the EMT and metastatic phenotype observed in a subset of ADT-resistant prostate cancer, where the CCL2 is stimulated through the inactivated of AR-mediated SPDEF.

Transforming growth factor-β in stem cells and tissue homeostasis

TGF-β 1-3 are unique multi-functional growth factors that are only expressed in mammals, and mainly secreted and stored as a latent complex in the extracellular matrix (ECM). The biological functions of TGF-β in adults can only be delivered after ligand activation, mostly in response to environmental perturbations. Although involved in multiple biological and pathological processes of the human body, the exact roles of TGF-β in maintaining stem cells and tissue homeostasis have not been well-documented until recent advances, which delineate their functions in a given context. Our recent findings, along with data reported by others, have clearly shown that temporal and spatial activation of TGF-β is involved in the recruitment of stem/progenitor cell participation in tissue regeneration/remodeling process, whereas sustained abnormalities in TGF-β ligand activation, regardless of genetic or environmental origin, will inevitably disrupt the normal physiology and lead to pathobiology of major diseases. Modulation of TGF-β signaling with different approaches has proven effective pre-clinically in the treatment of multiple pathologies such as sclerosis/fibrosis, tumor metastasis, osteoarthritis, and immune disorders. Thus, further elucidation of the mechanisms by which TGF-β is activated in different tissues/organs and how targeted cells respond in a context-dependent way can likely be translated with clinical benefits in the management of a broad range of diseases with the involvement of TGF-β.

Involvement of platelet-derived growth factor ligands and receptors in tumorigenesis

Platelet-derived growth factor (PDGF) isoforms and their receptors have important roles during embryogenesis, particularly in the development of various mesenchymal cell types in different organs. In the adult, PDGF stimulates wound healing and regulates tissue homeostasis. However, overactivity of PDGF signalling is associated with malignancies and other diseases characterized by excessive cell proliferation, such as fibrotic conditions and atherosclerosis. In certain tumours, genetic or epigenetic alterations of the genes for PDGF ligands and receptors drive tumour cell proliferation and survival. Examples include the rare skin tumour dermatofibrosarcoma protuberance, which is driven by autocrine PDGF stimulation due to translocation of a PDGF gene, and certain gastrointestinal stromal tumours and leukaemias, which are driven by constitute activation of PDGF receptors due to point mutations and formation of fusion proteins of the receptors, respectively. Moreover, PDGF stimulates cells in tumour stroma and promotes angiogenesis as well as the development of cancer-associated fibroblasts, both of which promote tumour progression. Inhibitors of PDGF signalling may thus be of clinical usefulness in the treatment of certain tumours.