HOXA9 inhibits HIF-1α-mediated glycolysis through interacting with CRIP2 to repress cutaneous squamous cell carcinoma development

Hypoxia-Induced Cancer Cell Responses Driving Radioresistance of Hypoxic Tumors: Approaches to Targeting and Radiosensitizing

Simple Summary

Some regions of aggressive malignancies experience hypoxia due to inadequate blood supply. Cancer cells adapting to hypoxic conditions somehow become more resistant to radiation exposure and this decreases the efficacy of radiotherapy toward hypoxic tumors. The present review article helps clarify two intriguing points: why hypoxia-adapted cancer cells turn out radioresistant and how they can be rendered more radiosensitive. The critical molecular targets associated with intratumoral hypoxia and various approaches are here discussed which may be used for sensitizing hypoxic tumors to radiotherapy.

Abstract

Within aggressive malignancies, there usually are the “hypoxic zones”—poorly vascularized regions where tumor cells undergo oxygen deficiency through inadequate blood supply. Besides, hypoxia may arise in tumors as a result of antiangiogenic therapy or transarterial embolization. Adapting to hypoxia, tumor cells acquire a hypoxia-resistant phenotype with the characteristic alterations in signaling, gene expression and metabolism. Both the lack of oxygen by itself and the hypoxia-responsive phenotypic modulations render tumor cells more radioresistant, so that hypoxic tumors are a serious challenge for radiotherapy. An understanding of causes of the radioresistance of hypoxic tumors would help to develop novel ways for overcoming this challenge. Molecular targets for and various approaches to radiosensitizing hypoxic tumors are considered in the present review. It is here analyzed how the hypoxia-induced cellular responses involving hypoxia-inducible factor-1, heat shock transcription factor 1, heat shock proteins, glucose-regulated proteins, epigenetic regulators, autophagy, energy metabolism reprogramming, epithelial–mesenchymal transition and exosome generation contribute to the radioresistance of hypoxic tumors or may be inhibited for attenuating this radioresistance. The pretreatments with a multitarget inhibition of the cancer cell adaptation to hypoxia seem to be a promising approach to sensitizing hypoxic carcinomas, gliomas, lymphomas, sarcomas to radiotherapy and, also, liver tumors to radioembolization.

G6PD-NF-κB-HGF Signal in Gastric Cancer-Associated Mesenchymal Stem Cells Promotes the Proliferation and Metastasis of Gastric Cancer Cells by Upregulating the Expression of HK2

Background: Tumor-associated stromal cells have been widely recognized for their tumor-promoting capability involving paracrine signaling. However, the underlying mechanism and the effects of the molecules in the glycolysis pathway in gastric cancer-associated mesenchymal stem cells (GCMSCs) and gastric cancer cells on tumor progression remain unclear.

Methods: The expression of hepatocyte growth factor (HGF) in GCMSCs and bone marrow mesenchymal stem cells (BMMSCs) was detected by enzyme-linked immunosorbent assay (ELISA). The effect of HGF derived from GCMSCs on the proliferation, metastasis, and HK2 expression of gastric cancer cells was evaluated in vitro and in vivo. The effects of G6PD on the production of HGF in mesenchymal stem cells (MSCs) were analyzed by immunoblotting.

Results: HGF derived from GCMSCs promoted glycolysis, proliferation, and metastasis of gastric cancer by upregulating c-Myc-HK2 signal. The progression of the disease induced by GCMSCs decelerated in the absence of HK2. The expression of G6PD activated NF-κB signaling and stimulated the production of HGF in GCMSCs. Blocking HGF derived from GCMSCs decreased proliferation, metastasis, and angiogenesis of gastric cancer cells in vivo.

Conclusions: GCMSCs highly expressed G6PD and facilitated the progression of gastric cancer through the G6PD-NF-κB-HGF axis coordinates. Blocking HGF derived from GCMSCs is a potential new therapeutic target for the treatment of gastric cancer.

Development of a novel RNAi therapy: Engineered miR-31 exosomes promoted the healing of diabetic wounds

RATIONALE

Chronic wounds associated with diabetes exact a heavy burden on individuals and society and do not have a specific treatment. Exosome therapy is an extension of stem cell therapy, and RNA interference (RNAi)-based therapy is a type of advanced precision therapy. Based on the discovery of chronic wound-related genes in diabetes, we combined exosome therapy and RNAi therapy through an engineering approach for the treatment of diabetic chronic wounds.

METHODS

We combined exosome therapy and RNAi therapy to establish a precision therapy for diabetes-associated wounds via an engineered exosome approach.

RESULTS

First, chronic diabetic wounds express low levels of miR-31-5p compared with nondiabetic wounds, and an miR-31-5p mimic was shown to be effective in promoting the proliferation and migration of three wound-related cell types in vitro. Second, bioinformatics analysis, luciferase reporter assays and western blotting suggested that miR-31-5p promoted angiogenesis, fibrogenesis and reepithelization by inhibiting factor-inhibiting HIF-1 (HIF1AN, also named FIH) and epithelial membrane protein-1 (EMP-1). Third, engineered miR-31 exosomes were generated as a miR-31-5p RNAi therapeutic agent. In vivo, the engineered miR-31 exosomes promoted diabetic wound healing by enhancing angiogenesis, fibrogenesis and reepithelization.

CONCLUSION

Engineered miR-31 exosomes are an ideal disease pathophysiology-initiated RNAi therapeutic agent for diabetic wounds.

Tubular Numb promotes renal interstitial fibrosis via modulating HIF-1α protein stability

Tubulointerstitial fibrosis is the ultimate common pathway of all manners of chronic kidney disease. We previously demonstrated that specific deletion of Numb in proximal tubular cells (PTCs) prevented G2/M arrest and attenuated renal fibrosis. However, how Numb modulates cell cycle arrest remains unclear. Here, we showed that Numb overexpression significantly increased the protein level of hypoxia-inducible factor-1α (HIF-1α). Numb overexpression-induced G2/M arrest was blocked by silencing endogenous HIF-1α, subsequently downregulated the expression of cyclin G1 which is an atypical cyclin to promote G2/M arrest of PTCs. Further analysis revealed that Numb-augmented HIF-1α protein was blocked by simultaneously overexpressing MDM2. Moreover, silencing Numb decreased TGF-β1-induceded HIF-1α protein expression. While endogenous MDM2 was knocked down this reduction was reversed, indicating that Numb stabilized HIF-1α protein via interfering MDM2-mediated HIF-1α protein degradation. Interestingly, HIF-1α overexpression significantly upregulated the expression of Numb and silencing endogenous HIF-1α blocked CoCl₂ or TGF-β1-induced Numb expression. Chromatin immunoprecipitation (ChIP) assays demonstrated that HIF-1α binded to the promoter region of Numb. This binding was significantly increased by TGF-β1. Collectively, these data indicate that Numb and HIF-1α cooperates to promote G2/M arrest of PTCs, and thus aggravates tubulointerstitial fibrosis. Numb might be a potential target for the therapy of tubulointerstitial fibrosis.

MiR-103a-3p promotes tumour glycolysis in colorectal cancer via hippo/YAP1/HIF1A axis

Background

Glycolysis plays an essential role in the growth and metastasis of solid cancer and has received increasing attention in recent years. However, the complex regulatory mechanisms of tumour glycolysis remain elusive. This study aimed to explore the molecular effect and mechanism of the noncoding RNA miR-103a-3p on glycolysis in colorectal cancer (CRC).

Methods

We explored the effects of miR-103a-3p on glycolysis and the biological functions of CRC cells in vitro and in vivo. Furthermore, we investigated whether miR-103a-3p regulates HIF1A expression through the Hippo/YAP1 pathway, and evaluated the role of the miR-103a-3p-LATS2/SAV1-YAP1-HIF1A axis in promoting glycolysis and angiogenesis in CRC cells and contributed to invasion and metastasis of CRC cells.

Results

We found that miR-103a-3p was highly expressed in CRC tissues and cell lines compared with matched controls and the high expression of miR-103a-3p was associated with poor patient prognosis. Under hypoxic conditions, a high level of miR-103a-3p promoted the proliferation, invasion, migration, angiogenesis and glycolysis of CRC cells. Moreover, miR-103a-3p knockdown inhibited the growth, proliferation, and glycolysis of CRC cells and promoted the Hippo-YAP1 signalling pathway in nude mice in a xenograft model. Here, we demonstrated that miR-103a-3p could directly target LATS2 and SAV1. Subsequently, we verified that TEAD1, a transcriptional coactivator of Yes-associated protein 1 (YAP1), directly bound to the HIF1A promoter region and the YAP1 and TEAD1 proteins co-regulated the expression of HIF1A, thus promoting tumour glycolysis.

Conclusions

MiR-103a-3p, which is highly expressed in CRC cells, promotes HIF1A expression by targeting the core molecules LATS2 and SAV1 of the Hippo/YAP1 pathway, contributing to enhanced proliferation, invasion, migration, glycolysis and angiogenesis in CRC. Our study revealed the functional mechanisms of miR-103a-3p/YAP1/HIF1A axis in CRC glycolysis, which would provide potential intervention targets for molecular targeted therapy of CRC.

LncRNA and mRNA expression profile of peripheral blood mononuclear cells in primary Sjögren's syndrome patients

The aim of this study was to elucidate the expression profile and the potential role of long non-coding RNA (LncRNA) in the peripheral blood mononuclear cells of primary Sjögren’s syndrome (pSS) patients. RNA-seq technology was used to detect the differentially expressed LncRNAs and mRNAs between five age-and sex-matched paired pSS patients and healthy control PBMCs. The selected LncRNAs were detected in the validation study by RT-qPCR in 16 paired pSS patients and healthy controls. The GO, KEGG, co-localization, and co-expression analysis were performed to enrich the potential gene functions and pathways. In this study, 44 out of 1772 LncRNAs and 1034 out of 15,424 mRNAs were expressed differentially in the PBMCs of pSS patients. LINC00426, TPTEP1-202, CYTOR, NRIR, and BISPR were validated as aberrantly expressed, and these LncRNAs strongly correlated with disease activity of pSS. GO and KEGG pathway analysis revealed the significant enrichment of biological processes, cellular components, and molecular function of the up and down-regulated mRNAs, which were mainly concentrated in the immune response and immune system processes. Co-localization and co-expression analysis also revealed that differentially expressed LncRNAs in the PBMCs of pSS were strongly correlated to the mRNA functioning associated with immune response and cell metastasis. Numerous LncRNAs and mRNAs were found differentially expressed in the PBMCs of pSS patients, especially NRIR and BISPR; they interacted with the co-localized and co-expressed mRNAs, which might participate in the pathogenesis of pSS through the NF-κB, JAK-STAT, and other signaling pathways that regulate cell metastasis.

Epigenetic crosstalk between hypoxia and tumor driven by HIF regulation

Hypoxia is the major influence factor in physiological and pathological courses which are mainly mediated by hypoxia-inducible factors (HIFs) in response to low oxygen tensions within solid tumors. Under normoxia, HIF signaling pathway is inhibited due to HIF-α subunits degradation. However, in hypoxic conditions, HIF-α is activated and stabilized, and HIF target genes are successively activated, resulting in a series of tumour-specific activities. The activation of HIFs, including HIF-1α, HIF-2α and HIF-3α, subsequently induce downstream target genes which leads to series of responses, the resulting abnormal processes or metabolites in turn affect HIFs stability. Given its functions in tumors progression, HIFs have been regarded as therapeutic targets for improved treatment efficacy. Epigenetics refers to alterations in gene expression that are stable between cell divisions, and sometimes between generations, but do not involve changes in the underlying DNA sequence of the organism. And with the development of research, epigenetic regulation has been found to play an important role in the development of tumors, which providing accumulating basic or clinical evidences for tumor treatments. Here, given how little has been reported about the overall association between hypoxic tumors and epigenetics, we made a more systematic review from epigenetic perspective in hope of helping others better understand hypoxia or HIF pathway, and providing more established and potential therapeutic strategies in tumors to facilitate epigenetic studies of tumors.

A pan-cancer analysis of molecular characteristics and oncogenic role of hexokinase family genes in human tumors

Hexokinase (HK) plays a key role in various biological processes such as glycolysis of tumor cells. However, there is still a lack of systematic understanding of the contribution of HK family genes in different types of cancer. In the present study, we systematically analyzed the molecular changes and clinical correlations of HK family genes in 33 types of cancer extracted from more than 10,000 subjects. As a result, there were extensive genetic changes in HK family genes and the expression levels of HK family were significantly correlated with the activity of cancer marker-related pathways. In addition, HK family genes may be useful in predicting prognosis and therapeutic efficacy. Moreover, HK1,HK2 and HK3 may become potential oncogenes across a variety of cancer types. Furthermore, the oncogenic functions of HK1 in bladder cancer have been confirmed in vitro. Collectively, our results provide valuable resources to guide the mechanism and therapeutic analysis concerning the role of HK family genes in cancer.

Regulation of Glycolysis by Non-coding RNAs in Cancer: Switching on the Warburg Effect

The “Warburg effect” describes the reprogramming of glucose metabolism away from oxidative phosphorylation toward aerobic glycolysis, and it is one of the hallmarks of cancer cells. Several factors can be involved in this process, but in this review, the roles of non-coding RNAs (ncRNAs) are highlighted in several types of human cancer. ncRNAs, including microRNAs, long non-coding RNAs, and circular RNAs, can all affect metabolic enzymes and transcription factors to promote glycolysis and modulate glucose metabolism to enhance the progression of tumors. In particular, the 5′-AMP-activated protein kinase (AMPK) and the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathways are associated with alterations in ncRNAs. A better understanding of the roles of ncRNAs in the Warburg effect could ultimately lead to new therapeutic approaches for suppressing cancer.

Quantitative proteomics reveals specific metabolic features of acute myeloid leukemia stem cells

Acute myeloid leukemia is characterized by the accumulation of clonal myeloid blast cells unable to differentiate into mature leukocytes. Chemotherapy induces remission in the majority of patients, but relapse rates are high and lead to poor clinical outcomes. Because this is primarily caused by chemotherapy-resistant leukemic stem cells (LSCs), it is essential to eradicate LSCs to improve patient survival. LSCs have predominantly been studied at the transcript level, thus information about posttranscriptionally regulated genes and associated networks is lacking. Here, we extend our previous report on LSC proteomes to healthy age-matched hematopoietic stem and progenitor cells (HSPCs) and correlate the proteomes to the corresponding transcriptomes. By comparing LSCs to leukemic blasts and healthy HSPCs, we validate candidate LSC markers and highlight novel and potentially targetable proteins that are absent or only lowly expressed in HSPCs. In addition, our data provide strong evidence that LSCs harbor a characteristic energy metabolism, adhesion molecule composition, as well as RNA-processing properties. Furthermore, correlating proteome and transcript data of the same individual samples highlights the strength of proteome analyses, which are particularly potent in detecting alterations in metabolic pathways. In summary, our study provides a comprehensive proteomic and transcriptomic characterization of functionally validated LSCs, blasts, and healthy HSPCs, representing a valuable resource helping to design LSC-directed therapies.

Molecular prediction of metastasis in cutaneous squamous cell carcinoma

PURPOSE OF REVIEW

Cutaneous squamous cell carcinoma (cSCC) is a highly prevalent malignancy frequently occurring on body surfaces chronically exposed to ultraviolet radiation. While a large majority of tumors remain localized to the skin and immediate subcutaneous tissue and are cured with surgical excision, a small subset of patients with cSCC will develop metastatic disease. Risk stratification for cSCC is performed using clinical staging systems, but given a high mutational burden and advances in targeted and immunotherapy, there is growing interest in molecular predictors of high-risk disease.

RECENT FINDINGS

Recent literature on the risk for metastasis in cSCC includes notable findings in genes involved in cell-cycle regulation, tumor suppression, tissue invasion and microenvironment, interactions with the host-immune system, and epigenetic regulation.

SUMMARY

cSCC is a highly mutated tumor with complex carcinogenesis. Regulators of tumor growth and local invasion are numerous and increasingly well-understood but drivers of metastasis are less established. Areas of importance include central system regulators (NOTCH, miRNAs), proteins involved in tissue invasion (podoplanin, E-cadherin), and targets of existing and emerging therapeutics (PD-1, epidermal growth factor receptor). Given the complexity of cSCC carcinogenesis, the use of machine learning algorithms and computational genomics may provide ultimate insight and prospective studies are needed to verify clinical relevance.

APE1 promotes proliferation and migration of cutaneous squamous cell carcinoma

BACKGROUND

Human Apurinic/Apyrimidinic Endonuclease 1 (APE1/REF-1/HAP1) is a multifunction protein involved in the progression of cancer. But the role of APE1 in cutaneous squamous cell carcinoma (cSCC) is unclear.

OBJECTIVE

This study is aimed to investigate the basic modulatory mechanism of APE1 in cSCC development and offer a novel potential target for clinical treatment.

METHODS

The expression of APE1 in cSCC tissues was detected by western blot and immunohistochemistry (IHC) staining. The function of APE1 and miR-27a in cSCC cells was investigated by cell counting kit-8 (CCK-8) assays, colony formation assays and transwell migration assays. Western blot was used to determine the expression of APE1 in cSCC and epithelial-mesenchymal transition (EMT) markers in HSC-1 and HSC-5 cells with APE1 knockdown or overexpression. Double luciferase reporter assays were performed to confirm the interaction of miR-27a and APE1.

RESULTS

We identified that APE1 was significantly upregulated in human cSCC tissues and cSCC cells and its overexpression promoted cell proliferation, migration and the expression of EMT markers in cSCC cells. Mechanistically, miR-27a was predicted and confirmed as the upstream of APE1. Its downregulation also enhanced the proliferation and migration of cSCC cells. Rescue experiments demonstrated that restoration of APE1 expression significantly abolished the inhibition of cell proliferation and migration mediated by miR-27a.

CONCLUSION

As a direct gene of miR-27a, APE1 improved cell proliferation and migration to promote the progression of cSCC, which could be considered as a potential therapeutic target for cSCC treatment.

MiR-5683 suppresses glycolysis and proliferation through targeting pyruvate dehydrogenase kinase 4 in gastric cancer

Gastric cancer (GC) is one of the most deadly malignancies at global scale, and is particularly common in eastern Asia. MicroRNA‐5683 (miR‐5683) was confirmed to be downregulated in GC by analyzing data from the Cancer Genome Atlas. We packaged miR‐5683‐mimics and miR‐5683‐inhibitors into lentivirus vectors and transfected them into GC cells. MiR‐5683 expression and possible target genes were detected by employing quantitative real‐time polymerase chain reaction. In vitro, cell proliferation and apoptosis were analyzed using CCK‐8, colony formation assay, and flow cytometric assay. We verified the direct interaction between miR‐5683 and the possible downstream target gene pyruvate dehydrogenase kinase 4 (PDK4) through luciferase reporter assay. The role of miR‐5683 in vivo was explored by injecting stably transfected GC cells subcutaneously into nude mice. Here we show that miR‐5683 was downregulated in GC and the decreased level of miR‐5683 enhances GC cell proliferation and impairs apoptosis. Tumor oncogene PDK4, which is associated with GC overall survival and disease‐free survival, has been identified as the target gene of miR‐5683. Besides, we demonstrate that the inhibition of miR‐5683 promotes glycolysis by upregulating the PDK4 expression, thus leading to GC progression. Our study determines that miR‐5683 represses GC glycolysis and progression through targeting PDK4. MiR‐5683 overexpression may thus become a new treatment strategy for GC.

Integration of proteomics with CT-based qualitative and radiomic features in high-grade serous ovarian cancer patients: an exploratory analysis

OBJECTIVES

To investigate the association between CT imaging traits and texture metrics with proteomic data in patients with high-grade serous ovarian cancer (HGSOC).

METHODS

This retrospective, hypothesis-generating study included 20 patients with HGSOC prior to primary cytoreductive surgery. Two readers independently assessed the contrast-enhanced computed tomography (CT) images and extracted 33 imaging traits, with a third reader adjudicating in the event of a disagreement. In addition, all sites of suspected HGSOC were manually segmented texture features which were computed from each tumor site. Three texture features that represented intra- and inter-site tumor heterogeneity were used for analysis. An integrated analysis of transcriptomic and proteomic data identified proteins with conserved expression between primary tumor sites and metastasis. Correlations between protein abundance and various CT imaging traits and texture features were assessed using the Kendall tau rank correlation coefficient and the Mann-Whitney U test, whereas the area under the receiver operating characteristic curve (AUC) was reported as a metric of the strength and the direction of the association. P values < 0.05 were considered significant.

RESULTS

Four proteins were associated with CT-based imaging traits, with the strongest correlation observed between the CRIP2 protein and disease in the mesentery (p < 0.001, AUC = 0.05). The abundance of three proteins was associated with texture features that represented intra-and inter-site tumor heterogeneity, with the strongest negative correlation between the CKB protein and cluster dissimilarity (p = 0.047, τ = 0.326).

CONCLUSION

This study provides the first insights into the potential associations between standard-of-care CT imaging traits and texture measures of intra- and inter-site heterogeneity, and the abundance of several proteins.

KEY POINTS

• CT-based texture features of intra- and inter-site tumor heterogeneity correlate with the abundance of several proteins in patients with HGSOC. • CT imaging traits correlate with protein abundance in patients with HGSOC.

Deciphering the Molecular Landscape of Cutaneous Squamous Cell Carcinoma for Better Diagnosis and Treatment

Cutaneous squamous cell carcinoma (cSCC) is a common type of neoplasia, representing a terrible burden on patients' life and clinical management. Although it seldom metastasizes, and most cases can be effectively treated with surgical intervention, once metastatic cSCC displays considerable aggressiveness leading to the death of affected individuals. No consensus has been reached as to which features better characterize the aggressive behavior of cSCC, an achievement hindered by the high mutational burden caused by chronic ultraviolet light exposure. Even though some subtypes have been recognized as high risk variants, depending on certain tumor features, cSCC that are normally thought of as low risk could pose an increased danger to the patients. In light of this, specific genetic and epigenetic markers for cutaneous SCC, which could serve as reliable diagnostic markers and possible targets for novel treatment development, have been searched for. This review aims to give an overview of the mutational landscape of cSCC, pointing out established biomarkers, as well as novel candidates, and future possible molecular therapies for cSCC.

USP22 promotes hypoxia-induced hepatocellular carcinoma stemness by a HIF1α/USP22 positive feedback loop upon TP53 inactivation

OBJECTIVE

We aimed to elucidate the mutual regulation mechanism of ubiquitin-specific protease 22 (USP22) and hypoxia inducible factor-1α (HIF1α), and the mechanism they promote the stemness of hepatocellular carcinoma (HCC) cells under hypoxic conditions.

DESIGN

Cell counting, migration, self-renewal ability, chemoresistance and expression of stemness genes were established to detect the stemness of HCC cells. Immunoprecipitation, ubiquitination assay and chromatin immunoprecipitation assay were used to elucidate the mutual regulation mechanism of USP22 and HIF1α. HCC patient samples and The Cancer Genome Atlas data were used to demonstrate the clinical significance. In vivo USP22-targeting experiment was performed in mice bearing HCC.

RESULTS

USP22 promotes hypoxia-induced HCC stemness and glycolysis by deubiquitinating and stabilising HIF1α. As direct target genes of HIF1α, USP22 and TP53 can be transcriptionally upregulated by HIF1α under hypoxic conditions. In TP53 wild-type HCC cells, HIF1α induced TP53-mediated inhibition of HIF1α-induced USP22 upregulation. In TP53-mutant HCC cells, USP22 and HIF1α formed a positive feedback loop and promote the stemness of HCC. HCC patients with a loss-of-function mutation at TP53 and high USP22 and/or HIF1α expression tend to have a worse prognosis. The USP22-targeting lipopolyplexes caused high tumour inhibition and high sorafenib sensitivity in mice bearing HCC.

CONCLUSION

USP22 promotes hypoxia-induced HCC stemness by a HIF1α/USP22 positive feedback loop on TP53 inactivation. USP22 is a promising target for the HCC therapy.

miR-429 inhibits osteosarcoma progression by targeting HOXA9 through suppressing Wnt/β-catenin signaling pathway

Osteosarcoma (OS) is the most commonly diagnosed malignant cancer of bone that occurs in adolescents and children. Mounting number of studies have indicated that miRNAs are increasingly playing fundamental roles in OS development. Thus, the biological function of miR-429 in OS progression was explored. The results of RT-qPCR revealed that miR-429 was downregulated in OS tissues and OS cell lines (MG-63, U2OS, Saos-2) while homeobox A9 (HOXA9) was markedly increased. Moreover, HOXA9 was confirmed as a direct target of miR-429 by using luciferase reporter assay. It was identified that miR-429 exhibited a suppressive effect on OS progression while HOXA9 showed the oncogenic function in OS progression by using MTT and Transwell assays. More importantly, rescue assays manifested that HOXA9 can partially overturn the suppressive effect of miR-429 on OS. Overexpression of miR-429 inhibited the activation of Wnt/β-catenin signaling pathway. In conclusion, miR-429 suppressed OS progression by targeting HOXA9 through Wnt/β-catenin pathway.

MiR-664 Protects Against UVB Radiation-Induced HaCaT Cell Damage via Downregulating ARMC8

Background:

MiR-664 has been demonstrated to play an important role in dermal diseases. However, the functions of miR-664 in ultraviolet B (UVB) radiation-induced keratinocytes damage remain to be elucidated.

Objective:

The present study aimed to investigate the molecular mechanisms under the UVB-induced keratinocytes damage and provide translational insights for future therapeutics and UVB protection.

Methods:

HaCaT cells were transfected with miR-664, either alone or combined with UVB irradiation. Levels of messenger RNA and protein were tested by quantitative real-time polymerase chain reaction and Western blot analyses. Cell proliferation, percentage of apoptotic cells, and expression levels of apoptosis-related factors were measured by Cell Counting Kit-8 assay, flow cytometry assay, and Western blot analysis, respectively.

Results:

We found that a significant increase in miR-664 was observed in UVB-induced HaCaT cells. Overexpressed miR-664 promoted cell vitalities and suppressed apoptosis of UVB-induced HaCaT cells. Additionally, the loss/gain of armadillo-repeat-containing protein 8 (ARMC8) rescued/blocked the effects of miR-664 on the proliferation of UVB-induced HaCaT cells.

Conclusions:

Our data demonstrate that miR-664 functions as a protective regulator in UVB-induced HaCaT cells via regulating ARMC8.

Non-Coding RNAs Operate in the Crosstalk Between Cancer Metabolic Reprogramming and Metastasis

Metastasis, the spread of cancer cells from a primary tumor to a secondary site, represents one of the hallmarks of malignancies and the leading cause of cancer-related death. The process of metastasis is a result of the interaction of genetic heterogeneity, abnormal metabolism, and tumor microenvironments. On the other hand, metabolic reprogramming, another malignancy hallmark, refers to the ability of cancer cells to alter metabolic and nutrient acquisition modes in order to support the energy demands for accomplishing the rapid growth, dissemination, and colonization. Cancer cells remodel metabolic patterns to supplement nutrients for their metastasis and also undergo metabolic adjustments at different stages of metastasis. Genes and signaling pathways involved in tumor metabolic reprogramming crosstalk with those participating in metastasis. Non-coding RNAs are a group of RNA molecules that do not code proteins but have pivotal biological functions. Some of microRNAs and lncRNAs, which are the two most extensively studied non-coding RNAs, have been identified to participate in regulating metabolic remodeling of glucose, lipid, glutamine, oxidative phosphorylation, and mitochondrial respiration, as well as the process of metastasis involving cell motility, transit in the circulation and growth at a new site. This article reviews recent progress on non-coding RNAs operating in the crosstalk between tumor metabolic reprogramming and metastasis, particularly those influencing metastasis through regulating metabolism, and the underlying mechanisms of how they exert their regulatory functions.

Vitamin C decreases VEGF expression levels via hypoxia‑inducible factor‑1α dependent and independent pathways in lens epithelial cells

Posterior capsular opacification (PCO) is the main complication following cataract surgery. The proliferation of the residual lens epithelial cells (LECs) serves an important role in PCO formation. The authors' previous study revealed that vitamin C inhibited the proliferation of human LECs by increasing the rapid degradation of hypoxia-inducible factor-1 (HIF-1α), and hence inhibited the expression of vascular endothelial growth factor (VEGF). The present study aimed to further investigate the mechanisms underlying the effects of vitamin C on the expression levels of VEGF. The present study demonstrated that the HIF-1 inhibitor BAY 87–2243 significantly inhibited the cell proliferation and the expression levels of VEGF in LECs through the use of colony formation, western blotting and ELISA assays. Moreover, it was revealed that vitamin C could further inhibit the cell proliferation and the expression levels of VEGF in LECs following the cotreatment with the HIF-1 inhibitor. The proline hydroxylation of HIF-1α by prolyl hydroxylases (PHDs) was previously discovered to be responsible for the rapid degradation of HIF-1α. Thus, the present study subsequently used three PHD inhibitors to investigate their effects on the expression levels of VEGF; it was found that the PHD2 specific inhibitor increased the expression levels of VEGF to the greatest extent. Moreover, the genetic knockdown of PHD2 by lentiviral transfection also significantly increased the expression levels of VEGF, whereas the PHD2 specific inhibitor did not alter the expression levels of VEGF in the PHD2 knockdown LECs. AKT kinase activity is an important mediator known to upregulate VEGF expression. Using an immunoprecipitation assay to isolate endogenous AKT, it was demonstrated that AKT was prolyl hydroxylated by PHD2, which inhibited its activity. It was also revealed that vitamin C enhanced the proline-hydroxylation and inhibited the activity of AKT. Furthermore, an AKT inhibitor increased the effects of vitamin C on the expression levels of VEGF. However, the AKT inhibitor did not affect the expression levels of glucose transporter 1, which is a HIF-1α target gene. In conclusion, the findings of the present study suggested that vitamin C may inhibit the expression levels of VEGF via HIF-1α-dependent and AKT-dependent pathways in LECs.

Effect of glycolysis inhibition by miR-448 on glioma radiosensitivity

OBJECTIVE

Although glucose metabolism reengineering is a typical feature of various tumors, including glioma, key regulators of glycolytic reprogramming are still poorly understood. The authors sought to investigate whether glycolysis inhibition by microRNA (miR)-448 increases radiosensitivity in glioma cells.

METHODS

The authors used glioma tissue samples from glioma patients, cells from glioblastoma (GBM) cell lines and normal human astrocyte cells, and subcutaneous tumor-bearing U87 cells in mice to examine the effects of signaling regulation by miR-448 in the response of glioma tissues and cells to radiation treatment. Techniques used for investigation included bioinformatics analyses, biochemical assays, luciferase reporter assays, and establishment of subcutaneous tumors in a mouse model. Glucose consumption, LDH activity, and cellular ATP were measured to determine the ability of glioma cells to perform glycolysis. Expression of HIF-1α was measured as a potential target gene of miR-448 in glycolysis.

RESULTS

miR-448 was detected and determined to be significantly downregulated in both glioma tissues from glioma patients and GBM cell lines. Furthermore, miR-448 acted as a tumor-inhibiting factor and suppressed glycolysis in glioma by negatively regulating the activity of HIF-1α signaling and then interfering with its downstream regulators relative to glycolysis, HK1, HK2, and LDHA. Interestingly, overexpression of miR-448 increased the x-radiation sensitivity of glioma cells. Finally, in in vivo experiments, subcutaneous tumor-bearing U87 cells in a mouse model verified that high expression of miR-448 also enhanced glioma radiosensitivity via inhibiting glycolytic factors.

CONCLUSIONS

miR-448 can promote radiosensitivity by inhibiting HIF-1α signaling and then negatively controlling the glycolysis process in glioma. A newly identified miR-448-HIF-1α axis acts as a potentially valuable therapeutic target that may be useful in overcoming radioresistance in glioma treatment.

Histone methyltransferase SETD1A interacts with HIF1α to enhance glycolysis and promote cancer progression in gastric cancer

Growing tumors alter their metabolic profiles to support the increased cell proliferation. SETD1A, a histone lysine methyltransferase which specifically methylates H3K4, plays important roles in both normal cell and cancer cell functions. However, the function of SETD1A in gastric cancer (GC) progression and its role in GC metabolic reprogramming are still largely unknown. In the current study, we discovered that the expression of SETD1A was higher in GC tumor specimens compared to surrounding nontumor tissues. Upregulation of SETD1A increased GC cell proliferation, whereas downregulation of SETD1A inhibited GC cell proliferation. Furthermore, knockdown of SETD1A reduced glucose uptake and production of lactate and suppressed glycolysis by decreasing the expression of glycolytic genes, including GLUT1, HK2, PFK2, PKM2, LDHA, and MCT4. Mechanistically, SETD1A interacted with HIF1α to strengthen its transactivation, indicating that SETD1A promotes glycolysis through coactivation of HIF1α. SETD1A and HIF1α were recruited to the promoter of HK2 and PFK2, where SETD1A could methylate H3K4. However, knockdown of SETD1A decreased the methylation of H3K4 on HK2 and PFK2 promoter and reduced HIF1α recruitment necessary to promote transcription of glycolytic genes. Inhibition of HIF1α decelerated SETD1A‐enhanced GC cell growth. In additional, there was a linear correlation between SETD1A and several key glycolytic genes in human GC specimens obtained from TCGA dataset. Thus, our results demonstrated that SETD1A interacted with HIF1α to promote glycolysis and accelerate GC progression, implicating that SETD1A may be a potential molecular target for GC treatment.

High-salt diet inhibits tumour growth in mice via regulating myeloid-derived suppressor cell differentiation

High-salt diets are associated with an elevated risk of autoimmune diseases, and immune dysregulation plays a key role in cancer development. However, the correlation between high-salt diets (HSD) and cancer development remains unclear. Here, we report that HSD increases the local concentration of sodium chloride in tumour tissue, inducing high osmotic stress that decreases both the production of cytokines required for myeloid-derived suppressor cells (MDSCs) expansion and MDSCs accumulation in the blood, spleen, and tumour. Consequently, the two major types of MDSCs change their phenotypes: monocytic-MDSCs differentiate into antitumour macrophages, and granulocytic-MDSCs adopt pro-inflammatory functions, thereby reactivating the antitumour actions of T cells. In addition, the expression of p38 mitogen-activated protein kinase-dependent nuclear factor of activated T cells 5 is enhanced in HSD-induced M-MDSC differentiation. Collectively, our study indicates that high-salt intake inhibits tumour growth in mice by activating antitumour immune surveillance through modulating the activities of MDSCs.

Interleukin 1β-mediated HOXC10 Overexpression Promotes Hepatocellular Carcinoma Metastasis by Upregulating PDPK1 and VASP

Rationale: Metastasis and recurrence are the primary reasons for the high mortality rate of human hepatocellular carcinoma (HCC) patients. However, the exact mechanism underlying HCC metastasis remains unclear. The Homeobox (HOX) family proteins, which are a highly conserved transcription factor superfamily, play important roles in cancer metastasis. Here, we report a novel role of HOXC10, one of the most upregulated HOX genes in human HCC tissues, in promoting HCC metastasis.

Methods: The expression of HOXC10 and its functional targets was detected by immunohistochemistry in two independent human HCC cohorts. Luciferase reporter and chromatin immunoprecipitation assays were used to measure the transcriptional regulation of target genes by HOXC10. The effect of HOXC10-mediated invasion and metastasis were analyzed by Transwell assays and by an orthotopic metastasis model.

Results: Elevated expression of HOXC10 was positively correlated with the loss of tumor encapsulation and with higher tumor-nodule-metastasis (TNM) stage and poor prognosis in human HCC. Overexpression of HOXC10 promoted HCC metastasis by upregulating metastasis-related genes, including 3-phosphoinositide-dependent protein kinase 1 (PDPK1) and vasodilator-stimulated phosphoprotein (VASP). Knockdown of PDPK1 and VASP inhibited HOXC10-enhanced HCC metastasis, whereas upregulation of PDPK1 and VASP rescued the decreased metastasis induced by HOXC10 knockdown. Interleukin-1β (IL-1β), which is the ligand of IL-1R1, upregulated HOXC10 expression through the c-Jun NH2-terminal kinase (JNK)/c-Jun pathway. HOXC10 knockdown significantly reduced IL-1β-mediated HCC metastasis. Furthermore, Anakinra, a specific antagonist of IL-1R1, inhibited IL-1β-induced HOXC10 upregulation and HCC metastasis. In human HCC tissues, HOXC10 expression was positively correlated with PDPK1, VASP and IL-1R1 expression, and patients with positive coexpression of HOXC10/PDPK1, HOXC10/VASP or IL-1R1/HOXC10 exhibited the poorest prognosis.

Conclusions: Upregulated HOXC10 induced by IL-1β promotes HCC metastasis by transactivating PDPK1 and VASP expression. Thus, our study implicates HOXC10 as a prognostic biomarker, and targeting this pathway may be a promising therapeutic option for the clinical prevention of HCC metastasis.

HIF-1α or HOTTIP/CTCF Promotes Head and Neck Squamous Cell Carcinoma Progression and Drug Resistance by Targeting HOXA9

Head and neck squamous cell carcinoma (HNSCC) is the sixth most frequently diagnosed cancer worldwide. However, the clinical outcomes remain unsatisfactory. The aim of this study is to unravel the functional role and regulatory mechanism of HOXA9 in HNSCC. A cohort of 25 HNSCC tumor tissues and normal tissue counterparts was collected. qRT-PCR and western blotting were performed to determine the levels of HOXA9 and epithelial-mesenchymal transition (EMT)-related markers. Cell Counting Kit-8 (CCK-8) and colony formation assays were conducted to monitor cell viability and cytotoxicity. Transwell and wound healing assays were used to determine cell migration and invasion. Annexin V-fluorescein isothiocyanate/propidium iodide (FITC/PI) staining was performed to detect cell apoptosis. Bioinformatic analysis, electrophoretic mobility shift assay and chromatin immunoprecipitation (ChIP) assays were performed to investigate the direct binding between HIF-1α or CCCTC binding factor (CTCF) and HOXA9. Glutathione S-transferase (GST) pull-down and RNA pull-down assays were used to validate the interaction between CTCF and HOTTIP. HOXA9 was upregulated in HNSCC tissues and cells. Knockdown of HOXA9 inhibited cell proliferation, migration, invasion, and chemoresistance but promoted apoptosis in CAL-27 and KB cells. Knockdown of HOXA9 also regulated EMT-related marker via targeting YAP1/β-catenin. Silencing of HOTTIP or CTCF exerted similar tumor-suppressive effects in HNSCC. Mechanistically, HIF-1α or CTCF transcriptionally regulated HOXA9, and HOTTIP/CTCF cooperatively regulated HOXA9 in KB cells. HIF-1α or HOTTIP/CTCF transcriptionally modulates HOXA9 expression to regulate HNSCC progression and drug resistance.

LncRNA HOTAIR knockdown inhibits glycolysis by regulating miR-130a-3p/HIF1A in hepatocellular carcinoma under hypoxia

High rate of glycolysis supports hepatocellular carcinoma (HCC) cell growth even in a hypoxic environment. However, the mechanism underlying glycolysis under hypoxia remains largely unknown. Long noncoding RNAs (lncRNAs) play essential roles in regulating glucose metabolism in cancers. This study aimed to explore the role of lncRNA homeobox transcript antisense RNA (HOTAIR) in HCC glycolysis under hypoxia. Thirty-eight HCC patients were recruited. HepG2 and Huh7 cells were used for study in vitro. The expression levels of HOTAIR, microRNA-130a-3p (miR-130a-3p) and hypoxia inducible factor 1 alpha (HIF1A) were measured by quantitative real-time polymerase chain reaction and western blot, respectively. The glycolysis under hypoxia (1 % O₂) condition was investigated by glucose consumption, lactate production and hexokinase 2 (HK2) level. The target interaction between miR-130a-3p and HOTIR or HIF1A was analyzed by bioinformatics analysis, luciferase assay, RNA pull-down and RNA immunoprecipitation. We found that HOTAIR expression was enhanced in HCC tissues and cells. Under hypoxia condition, HOTAIR expression was increased and its knockdown inhibited glycolysis in HCC cells. HOTAIR was validated as a decoy of miR-130a-3p and miR-130a-3p deficiency reversed the suppressive effect of HOTAIR silence on glycolysis under hypoxia. HIF1A was indicated as a target of miR-130a-3p and miR-130a-3p overexpression repressed glycolysis under hypoxia by targeting HIF1A. Moreover, HIF1A expression was regulated by HOTAIR and miR-130a-3p. In conclusion, knockdown of HOTAIR suppressed glycolysis by regulating miR-130a-3p and HIF1A in HCC cells treated by hypoxia, elucidating a novel mechanism in HCC glycolysis.

miR-27a Downregulation Promotes Cutaneous Squamous Cell Carcinoma Progression via Targeting EGFR

Cutaneous squamous cell carcinoma (cSCC) is the second common malignant cancer around the worldwide and is etiologically linked to ultraviolet radiation. miRNAs play an important role in the initiation and progression of cancers. However, the functions of miRNAs in cSCC remain to be elucidated. Here, we screened and identified miR-27a as a consistently downregulated miRNA after UVB irradiation in HaCaT cells. It was found that miR-27a expression was significantly decreased in cSCC cells and tissues. in vitro and in vivo experiments showed that miR-27a inhibited cell proliferation and invasion of cSCC cells. Mechanistically, EGFR was identified to be directly targeted by miR-27a and miR-27a suppressed the phosphorylation of EGFR and its downstream NF-κB signaling pathway. Overall, these findings suggest that downregulation of miR-27a promotes tumor growth and metastasis via targeting EGFR and its downstream NF-κB signaling pathway, reminding that miR-27a plays a vital role in the progression of cSCC and could be a new therapeutic target.

miR-652 Promotes Proliferation and Migration of Uveal Melanoma Cells by Targeting HOXA9

Background

Dysregulation of the microRNA (miRNA) network is a typical feature of many cancers. However, the key specific miRNAs involved in uveal melanoma carcinogenesis are largely unknown.

Material/Methods

RT-qPCR was used to detected miR-652 expression in uveal melanoma tissues and cell lines. miR-652 inhibitor was transfected into uveal melanoma cells to decrease miR-652 expression and determine the biological role of miR-652 by CCK-8 and wound healing assays. Bioinformatic analysis and dual luciferase reporter assay were used to predict and validate the target gene of miR-652. HOXA9 siRNA was transfected into cells to confirm that miR-652 relies on regulation of HOXA9 to regulate cell proliferation and migration.

Results

RT-qPCR showed that miR-652 was overexpressed in uveal melanoma cell lines (MUM-2B, MEL270) compared with melanocyte cells (ARPE-19). Overexpression of miR-652 was also observed in uveal melanoma compared to paired non-tumor tissues. Downregulation of miR-652 inhibited the cell proliferation ability and migration ability of uveal melanoma cells. Using bioinformatic analysis, HOXA9 was found to be a potential target gene of miR-652. The direct regulation of HOXA9 by miR-652 was experimentally validated in uveal melanoma cells by dual luciferase assay and Western blotting. We also observed that miR-652 promoted HIF-1α signaling via repression of HOXA9 in uveal melanoma cells. Silencing of HOXA9 attenuated the miR-652 inhibitor decreased cell growth rate and decreased migration ability in uveal melanoma cells.

Conclusions

Our data demonstrate an oncogenic role of miR-652 in uveal melanoma, showing that miR-652 may be a useful biomarker for prediction of prognosis for patients with uveal melanoma.

Kidney-secreted erythropoietin lowers lipidemia via activating JAK2-STAT5 signaling in adipose tissue

Background

Dyslipidemia is commonly observed in various kidney diseases, renal specific secreted erythropoietin (EPO) may participate in this process. However, how this process is regulated remains elusive.

Method

Dyslipidemia was evaluated in chronic kidney disease and ischemia kidney injury animal model. Primary cultured adipocytes were harvested to investigate the lipid metabolic effect of EPO. Lipidemia was evaluated in EPO treated animals. Blood samples from cardiac surgery-induced kidney injury patient were collected to assess correlationship between EPO and lipidemia.

Findings

We found a decrease in secreted EPO and hypertriglyceridemia in chronic kidney disease (CKD) mice. In contrast, in renal ischemia animal model, increased EPO triggered by hypoxia signaling activation, was accompanied by decreased triglyceride (TG) in serum. Mechanistically, circulating EPO modulated JAK2-STAT5 signaling, which in turn enhanced lipid catabolism in peripheral adipose tissue and contributed to dysregulated lipidemia. Delivering of recombinant EPO into both wild type and CKD mice suppressed TG in serum by accelerating lipid catabolism in adipose tissue. In a cohort of patients diagnosed with acute kidney injury after cardiopulmonary bypass surgery, the decreased TG and cholesterol negatively correlated with increased EPO in serum.

Interpretation

This study depicted a new mechanism by which renal secreted EPO controlled lipidemia in kidney diseases including chronic kidney disease. Circulating EPO stimulated lipid catabolism by targeting JAK2-STATA5 signaling in peripheral adipose tissue, providing new therapeutic target for dyslipidemia treatment.

Funding

This work was supported by grants from the National Natural Science Foundation of China (Nos. 81700640 and 81970608).

HOXA9 Transcriptionally Promotes Apoptosis and Represses Autophagy by Targeting NF-κB in Cutaneous Squamous Cell Carcinoma

Tumor suppressor HOXA9 has been identified to promote apoptosis in cutaneous squamous cell carcinoma (cSCC). However, the mechanism of such pro-apoptotic role of HOXA9 remains obscure. KEGG (Kyoto Encyclopedia of Genes and Genomes) analysis of RNA-seq data showed that NF-κB, apoptosis and autophagy pathways are significantly regulated after HOXA9 knockdown. HOXA9 transcriptionally regulates RELA, the p65 subunit of NF-κB. Loss of HOXA9 in cSCC significantly upregulates RELA expression and thus enhances NF-κB pathway. Interestingly, RELA transcriptionally promotes not only anti-apoptotic factor BCL-XL but also autophagic genes including ATG1, ATG3, and ATG12. Our results reveal an enhanced NF-κB signaling network regulated by HOXA9, which contributes to repressed apoptosis and activated autophagy in cSCC development and may represent an intervention target for cSCC therapy.

Polo-like kinase 3 inhibits glucose metabolism in colorectal cancer by targeting HSP90/STAT3/HK2 signaling

Background

Polo-like kinase 3 (PLK3) has been documented as a tumor suppressor in several types of malignancies. However, the role of PLK3 in colorectal cancer (CRC) progression and glucose metabolism remains to be known.

Methods

The expression of PLK3 in CRC tissues was determined by immunohistochemistry. Cells proliferation was examined by EdU, CCK-8 and in vivo analyses. Glucose metabolism was assessed by detecting lactate production, glucose uptake, mitochondrial respiration, extracellular acidification rate, oxygen consumption rate and ATP production. Chromatin immunoprecipitation, luciferase reporter assays and co-immunoprecipitation were performed to explore the signaling pathway. Specific targeting by miRNAs was determined by luciferase reporter assays and correlation with target protein expression.

Results

PLK3 was significantly downregulated in CRC tissues and its low expression was correlated with worse prognosis of patients. In vitro and in vivo experiments revealed that PLK3 contributed to growth inhibition of CRC cells. Furthermore, we demonstrated that PLK3 impeded glucose metabolism via targeting Hexokinase 2 (HK2) expression. Mechanically, PLK3 bound to Heat shock protein 90 (HSP90) and facilitated its degradation, which led to a significant decrease of phosphorylated STAT3. The downregulation of p-STAT3 further suppressed the transcriptional activation of HK2. Moreover, our investigations showed that PLK3 was directly targeted by miR-106b at post-transcriptional level in CRC cells.

Conclusion

This study suggests that PLK3 inhibits glucose metabolism by targeting HSP90/STAT3/HK2 signaling and PLK3 may serve as a potential therapeutic target in colorectal cancer.

Chloroquine promotes gefitinib‑induced apoptosis by inhibiting protective autophagy in cutaneous squamous cell carcinoma

Aberrant expression of the epidermal growth factor receptor (EGFR) plays vital roles in tumor development and progression. In the present study, ultraviolet irradiation induced the upregulation of EGFR in skin-derived keratinocytes, which may contribute to the development of cutaneous squamous cell carcinoma (CSCC). This was supported by the high expression of EGFR in CSCC clinical samples. Treating A431 CSCC cells with gefitinib, a tyrosine kinase inhibitor, activated the intrinsic mitochondrial apoptotic pathway while inducing protective autophagy. Combined application of chloroquine with gefitinib enhanced the treatment efficacy of gefitinib against CSCC by inhibiting autophagic flux. These findings demonstrated that autophagy inhibition may be an effective strategy for enhancing the sensitivity of EGFR-expressing cells to tyrosine kinase inhibitor treatment. Manipulating pro-survival autophagy by the combined application of chloroquine with gefitinib is a promising approach for improving the efficacy of EGFR inhibitors in cancer treatment. This may contribute to novel EGFR-targeted therapeutic strategies in the near future.

CD36 inhibits β-catenin/c-myc-mediated glycolysis through ubiquitination of GPC4 to repress colorectal tumorigenesis

The diverse expression pattern of CD36 reflects its multiple cellular functions. However, the roles of CD36 in colorectal cancer (CRC) remain unknown. Here, we discover that CD36 expression is progressively decreased from adenomas to carcinomas. CD36 loss predicts poor survival of CRC patients. In CRC cells, CD36 acts as a tumor suppressor and inhibits aerobic glycolysis in vitro and in vivo. Mechanically, CD36-Glypcian 4 (GPC4) interaction could promote the proteasome-dependent ubiquitination of GPC4, followed by inhibition of β-catenin/c-myc signaling and suppression of downstream glycolytic target genes GLUT1, HK2, PKM2 and LDHA. Moreover, disruption of CD36 in inflammation-induced CRC model as well as Apc^Min/+ mice model significantly increased colorectal tumorigenesis. Our results reveal a CD36-GPC4-β-catenin-c-myc signaling axis that regulates glycolysis in CRC development and may provide an intervention strategy for CRC prevention.

Secondary analysis of existing microarray data reveals potential gene drivers of cutaneous squamous cell carcinoma

Cutaneous squamous-cell carcinoma (cSCC) is the second most common skin cancer, with an increasing incidence in recent years. To define the molecular basis that drive cSCC development and progression, this study aimed at identifying potential novel molecular targets for the diagnosis and therapy of patients with cSCC. Two data sets with the accession number GSE45164 and GSE66359 were downloaded from Gene Expression Omnibus (GEO) database. After the identification of differentially expressed genes (DEGs) from these two data sets, respectively, between cSCC samples and controls, a combination of DEGs from these two data sets were subjected to the following analyses, including functional annotation, protein-protein interaction (PPI) network and module construction, transcription factor (TF)-target regulation prediction, and drug-gene interaction predictive analysis. A total of 204 upregulated genes and 213 downregulated genes were found in two data sets which were used for the follow-up analysis. Upregulated and downregulated genes were mainly involved in the functions such as cell division, mitotic nuclear division, cell cycle, and p53 signaling pathway. Interferon induced protein family members and proteasome subunit members were involved in the TF-target regulatory network, such as PSMB8, CXCL10, and IFIT3. Eight upregulated genes ( TOP2A, CXCL8, RRM2, PSMB8, PSMB9, PBK, CXCL10, and ISG15) that were hub genes in the PPI network and significant modules were identified in the predicted drug-gene interaction. In conclusion, TOP2A, CXCL8, RRM2, PSMB8, PSMB9, PBK, CXCL10, and ISG15 may be potential targets for the diagnosis and therapy of patients with cSCC.

MicroRNA Dysregulation in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (CSCC) is the second most frequent cancer in humans and it can be locally invasive and metastatic to distant sites. MicroRNAs (miRNAs or miRs) are endogenous, small, non-coding RNAs of 19–25 nucleotides in length, that are involved in regulating gene expression at a post-transcriptional level. MicroRNAs have been implicated in diverse biological functions and diseases. In cancer, miRNAs can proceed either as oncogenic miRNAs (onco-miRs) or as tumor suppressor miRNAs (oncosuppressor-miRs), depending on the pathway in which they are involved. Dysregulation of miRNA expression has been shown in most of the tumors evaluated. MiRNA dysregulation is known to be involved in the development of cutaneous squamous cell carcinoma (CSCC). In this review, we focus on the recent evidence about the role of miRNAs in the development of CSCC and in the prognosis of this form of skin cancer.

The Role of HOX Transcription Factors in Cancer Predisposition and Progression

Homeobox (HOX) transcription factors, encoded by a subset of homeodomain superfamily genes, play pivotal roles in many aspects of cellular physiology, embryonic development, and tissue homeostasis. Findings over the past decade have revealed that mutations in HOX genes can lead to increased cancer predisposition, and HOX genes might mediate the effect of many other cancer susceptibility factors by recognizing or executing altered genetic information. Remarkably, several lines of evidence highlight the interplays between HOX transcription factors and cancer risk loci discovered by genome-wide association studies, thereby gaining molecular and biological insight into cancer etiology. In addition, deregulated HOX gene expression impacts various aspects of cancer progression, including tumor angiogenesis, cell autophagy, proliferation, apoptosis, tumor cell migration, and metabolism. In this review, we will discuss the fundamental roles of HOX genes in cancer susceptibility and progression, highlighting multiple molecular mechanisms of HOX involved gene misregulation, as well as their potential implications in clinical practice.

Targeting cancer metabolism through synthetic lethality-based combinatorial treatment strategies

PURPOSE OF REVIEW

Targeting cancer metabolism for therapy has received much attention over the last decade with various small molecule inhibitors entering clinical trials. The present review highlights the latest strategies to target glucose and glutamine metabolism for cancer therapy with a particular emphasis on novel combinatorial treatment approaches.

RECENT FINDINGS

Inhibitors of glucose, lactate, and glutamine transport and the ensuing metabolism are in preclinical to clinical trial stages of investigation. Recent advances in our understanding of cell-intrinsic and cell-extrinsic factors that dictate dependence on these targets have informed the development of rational, synthetic lethality-based strategies to exploit these metabolic vulnerabilities.

SUMMARY

Cancer cells exhibit a number of metabolic alterations with functional consequences beyond that of sustaining cellular energetics and biosynthesis. Elucidating context-specific metabolic dependencies and their connections to oncogenic signaling and epigenetic programs in tumor cells represents a promising approach to identify new metabolic drug targets for cancer therapy.

PFKFB3 promotes endotoxemia-induced myocardial dysfunction through inflammatory signaling and apoptotic induction

Cardiac dysfunction is a vital complication during endotoxemia (ETM). Accumulating evidence suggests that enhanced glycolytic metabolism promotes inflammatory and myocardial diseases. In this study, we performed deep mRNA sequencing analysis on the hearts of control and lipopolysaccharide (LPS)-challenged mice (40 mg/kg, i.p.) and identified that the glycolytic enzyme, 6-phosphofructo-2-kinase (PFK-2)/fructose-2,6-bisphosphatase 3 (PFKFB3) might play an indispensable role in ETM-induced cardiac damage. Quantitative real-time PCR validated the transcriptional upregulation of PFKFB3 in the myocardium of LPS-challenged mice and immunoblotting and immunostaining assays confirmed that LPS stimulation markedly increased the expression of PFKFB3 at the protein level both in vivo and in vitro. The potent antagonist 3-(3pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO) was used to block PFKFB3 activity in vivo (50 mg/kg, i.p.) and in vitro (10 μM). Echocardiographic analysis and TUNEL staining showed that 3PO significantly alleviated LPS-induced cardiac dysfunction and apoptotic injury in vivo. 3PO also suppressed the LPS-induced secretion of tumor necrosis factor-α, interleukin (IL)-1β, IL-6 and lactate in the serum, in addition to lactate in the myocardium. PFKFB3 inhibition also diminished the nuclear translocation and phosphorylation of transcription factor nuclear factor-κB (NF-κB) in both adult cardiomyocytes and HL-1 cells. Furthermore, immunoblotting analysis showed that 3PO inhibited LPS-induced apoptotic induction in cardiomyocytes. Taken together, these findings demonstrate that PFKFB3 participates in LPS-induced cardiac dysfunction via mediating inflammatory and apoptotic signaling pathway.