Expressions of glucose transporter genes are diversely attenuated and significantly associated with prostate cancer progression.

Prostate cancer is a health-threaten disease in men worldwide, however, lacking is the reliable biomarkers for patient management. Aberrant metabolic events including glucose metabolism are involved in prostate cancer progression. To examine the involvement of glucose metabolic pathways in prostate cancer, we analyzed the expression profiles of glucose transporter family genes using multiple RNA-seq datasets. Our results showed that three SLC2A family genes (SLC2A4/5/9) were significantly downregulated in primary prostate cancers compared to their benign compartments. These down-regulated expressions were inversely correlated with their gene promoter methylation and genome abnormalities. Among these three SLC2A genes, only SLC2A4 showed a significantly reverse correlation with all clinicopathological parameters, including TNM stage, disease relapse, Gleason score, disease-specific survival, and progression-free interval. In addition, the expression levels of these three genes were strongly correlated with anti-cancer immune cell filtration in primary prostate cancers. In a group of patients with early-onset prostate cancers, SLC2A4 also showed a strong negative correlation with multiple clinicopathological parameters, such as tumor mutation burden, biochemical relapse, pre-surgical PSA levels, and Gleason score but a positive correlation with progression-free interval after surgery. In metastatic castration-resistant prostate cancers (CRPC), SLC2A9 gene expression but not SLC2A4 or SLC2A5 genes showed a significant correlation with androgen receptor (AR) activity score and neuroendocrinal (NE) activity score. Meanwhile, SLC2A2/9/13 expression was significantly elevated in CRPC tumors with neuroendocrinal features compared to those without NE features. On the other hand, SLC2A10 and SlC2A12 gene expression were significantly reduced in NEPC tumors compared to CRPC tumors. Consistently, SLC2A10/12 expression levels were significantly reduced in castrated animals carrying the LuCaP35 xenograft models. Survival outcome analysis revealed that SLC2A4 expression in primary tumors is a favorable prognostic factor and SLC2A6 is a worse prognostic factor for disease-specific survival and progression-free survival in prostate cancer patients. In conclusion, our results suggest that SLC2A4/6 expressions are strong prognostic factors for prostate cancer progression and survival. The significance of SLC2A2/9/13 over-expression during NEPC progression needs more investigation.

Zinc Fingers and Homeobox Family in Cancer: A Double-Edged Sword.

The zinc fingers and homeobox (ZHX) family includes ZHX1, ZHX2, and ZHX3, and their proteins have similar unique structures, containing two C2H2-type zinc finger motifs and four or five HOX-like homeodomains. The members of the ZHX family can form homodimers or heterodimers with each other or with a subunit of nuclear factor Y. Previous studies have suggested that ZHXs can function as positive or negative transcriptional regulators. Recent studies have further revealed their biological functions and underlying mechanisms in cancers. This review summarized the advances of ZHX-mediated functions, including tumor-suppressive and oncogenic functions in cancer formation and progression, the molecular mechanisms, and regulatory functions, such as cancer cell proliferation, migration, invasion, and metastasis. Moreover, the differential expression levels and their association with good or poor outcomes in patients with various malignancies and differential responses to chemotherapy exert opposite functions of oncogene or tumor suppressors. Therefore, the ZHXs act as a double-edged sword in cancers.

Oncogenic ACSM1 in prostate cancer is through metabolic and extracellular matrix-receptor interaction signaling pathways.

Acyl-coenzyme A synthetase medium chain family member 1 (ACSM1) is a medium chain Acyl-CoA Synthetase family member and plays an important role in fatty acid metabolism. The oncogenic roles of ACSM1 are largely unknown. Using comprehensive approaches, we analyzed gene expression profiles and genomic datasets and identified that the expression of ACSM1 was specifically increased in prostate cancer in comparison to the adjacent non-tumor tissues. The increased expression of ACSM1 was associated with increased risks of poor prognosis and shorter survival time. Moreover, genomic copy number alterations of ACSM1, including deletion, amplification, and amino acid changes were frequently observed in prostate cancers, although these mutations did not correlate with gene expression levels. However, ACSM1 gene amplifications were significantly corrected with increased risks of prostate cancer metastasis, and ACSM1 genetic alterations were significantly associated with worse disease-free. And progress-free survival. Gene function stratification and gene set enrichment analysis revealed that the oncogenic roles of ACSM1 in prostate cancer were mainly through metabolic pathways and extracellular matrix (ECM)-receptor interaction signaling pathways, but not associated with microenvironmental immunological signaling pathways, and that ACSM1 expression was not associated with immune cell infiltration in the cancer microenvironment or prostate cancer immune subtypes. In conclusion, the present work has demonstrated that ACSM1 can be specifically and significantly elevated in prostate cancer. ACSM1 gene expression and genomic amplification exhibit important clinical significance through metabolic and ECM-receptor interaction signaling pathways. Thus, ACSM1 may be a novel oncogene and serve as a biomarker for prostate cancer screening and prognosis prediction, and/or a therapeutic target.

Necroptosis pathway blockage attenuates PFKFB3 inhibitor-induced cell viability loss and genome instability in colorectal cancer cells.

Cancer cells prone to utilize aerobic glycolysis other than oxidative phosphorylation to sustain its continuous cell activity in the stress microenvironment. Meanwhile, cancer cells generally suffer from genome instability, and both radiotherapy and chemotherapy may arouse DNA strand break, a common phenotype of genome instability. Glycolytic enzyme PFKFB3 (6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3), plays essential roles in variety physiology and pathology processes, and generally maintain high level in cancer cells. Although this protein has been reported to involve in genome instability, its role remains unclear and controversial. Here, we showed that PFK-15, a PFKFB3 inhibitor, obviously induced apoptosis, cell viability loss, and inhibited cell proliferation/migration. Besides, PFK-15 was also found to induce necroptosis, as it not only up-regulated the phosphorylated RIP1, RIP3 and MLKL, but also enhanced the interaction between RIP3 and RIP1/MLKL, all of which are characterization of necroptosis induction. Both genetically and pharmacologically deprivation of necroptosis attenuated the cytotoxic effect of PFK-15. Besides, PFK-15 increased the γ-H2AX level and micronuclei formation, markers for genome instability, and inhibition of necroptosis attenuated these phenotypes. Collectively, the presented data demonstrated that PFK-15 induced genome instability and necroptosis, and deprivation of necroptosis attenuated cytotoxicity and genotoxicity of PFK-15 in colorectal cancer cells, thereby revealing a more intimate relationship among PFKFB3, necroptosis and genome instability.

E2F7-EZH2 axis regulates PTEN/AKT/mTOR signalling and glioblastoma progression.

BACKGROUND: E2F transcription factors are considered to be important drivers of tumour growth. E2F7 is an atypical E2F factor, and its role in glioblastoma remains undefined. METHODS: E2F7 expression was examined in patients by IHC and qRT-PCR. The overall survival probability was determined by statistical analyses. MTT assay, colony formation, cell-cycle assay, cell metastasis and the in vivo model were employed to determine the functional role of E2F7 in glioblastoma. Chromatin immunoprecipitation, luciferase assay and western blot were used to explore the underlying mechanisms. RESULTS: E2F7 was found to be up-regulated in glioblastoma patients, and high E2F7 expression was associated with poor overall survival in glioblastoma patients. Functional studies showed that E2F7 promoted cell proliferation, cell-cycle progression, cell metastasis and tumorigenicity abilities in vitro and in vivo. E2F7 promoted the transcription of EZH2 by binding to its promoter and increased H3K27me3 level. EZH2 recruited H3K27me3 to the promoter of PTEN and inhibited PTEN expression, and then activated the AKT/mTOR signalling pathway. In addition, restored expression of EZH2 recovered the abilities of cell proliferation and metastasis in E2F7-silencing cells. CONCLUSION: Collectively, our findings indicate that E2F7 promotes cell proliferation, cell metastasis and tumorigenesis via EZH2-mediated PTEN/AKT/mTOR pathway in glioblastoma.

Ibuprofen mediates histone modification to diminish cancer cell stemness properties via a COX2-dependent manner.

BACKGROUND: The anticancer potential of ibuprofen has created a broad interest to explore the clinical benefits of ibuprofen in cancer therapy. However, the current understanding of the molecular mechanisms involved in the anticancer potential of ibuprofen remains limited. METHODS: Cancer stemness assays to validate ibuprofen function in vitro and in vivo. Histone modification assays to check the effect of ibuprofen on histone acetylation/methylation, as well as the activity of HDAC and KDM6A/B. Inhibitors' in vivo assays to evaluate therapeutic effects of various inhibitors' combination manners. RESULTS: In our in vitro studies, we report that ibuprofen diminishes cancer cell stemness properties that include reducing the ALDH + subpopulation, side population and sphere formation in three cancer types. In our in vivo studies, we report that ibuprofen decreases tumour growth, metastasis and prolongs survival. In addition, our results showed that ibuprofen inhibits inflammation-related stemness gene expression (especially ICAM3) identified by a high-throughput siRNA platform. In regard to the underlying molecular mechanism of action, we report that ibuprofen reduces HDACs and histone demethylase (KDM6A/B) expression that mediates histone acetylation and methylation, and suppresses gene expression via a COX2-dependent way. In regard to therapeutic strategies, we report that ibuprofen combined HDAC/HDM inhibitors prevents cancer progression in vivo. CONCLUSIONS: The aforementioned findings suggest a molecular model that explains how ibuprofen diminishes cancer cell stemness properties. These may provide novel targets for therapeutic strategies involving ibuprofen in the prevention of cancer progression.

EGFR activates GDH1 transcription to promote glutamine metabolism through MEK/ERK/ELK1 pathway in glioblastoma.

Cancer metabolism research has recently been revived and its focus expanded from glucose and the Warburg's effects on other nutrients, such as glutamine. The underlying mechanism of oncogenic alterations of glutaminolysis remains unclear. Genetic alterations of EGFR are observed in ~50% of glioblastoma (GBM) patients, and have been found to play important roles in the metabolic abnormalities of GBM. In this study, we found that glutamine metabolism was upregulated after EGFR activation in a GDH1 (glutamate dehydrogenase 1)-dependent manner. Knockdown of GDH1 significantly reduced the cell proliferation, colony formation and tumorigenesis abilities of glioblastoma cells. Furthermore, we showed that GDH1-mediated glutaminolysis was involved in EGF-promoted cell proliferation. EGFR triggered the phosphorylation of ELK1 at Ser 383 through activating MEK/ERK signaling. Phosphorylated ELK1 enriched in the promoter of GDH1 to activate the transcription of GDH1, which then promoted glutamine metabolism. In addition, EGFR activation did not accelerate glutaminolysis in ELK1 knockdown or ELK1 Ser383-mutated cells. Collectively, our findings indicate that EGFR phosphorylates ELK1 to activate GDH1 transcription and glutaminolysis through MEK/ERK pathway, providing new insight into oncogenic alterations of glutamine metabolism.

Correction: PPA1 promotes NSCLC progression via a JNK- and TP53-dependent manner.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

PFKFB3 Inhibition Attenuates Oxaliplatin-Induced Autophagy and Enhances Its Cytotoxicity in Colon Cancer Cells.

6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3), a glycolytic enzyme highly expressed in cancer cells, has been reported to participate in regulating metabolism, angiogenesis, and autophagy. Although anti-cancer drug oxaliplatin (Oxa) effectively inhibits cell proliferation and induces apoptosis, the growing resistance and side-effects make it urgent to improve the therapeutic strategy of Oxa. Although Oxa induces the autophagy process, the role of PFKFB3 in this process remains unknown. In addition, whether PFKFB3 affects the cytotoxicity of Oxa has not been investigated. Here, we show that Oxa-inhibited cell proliferation and migration concomitant with the induction of apoptosis and autophagy in SW480 cells. Both inhibition of autophagy by small molecule inhibitors and siRNA modification decreased the cell viability loss and apoptosis induced by Oxa. Utilizing quantitative PCR and immunoblotting, we observed that Oxa increased PFKFB3 expression in a time- and dose-dependent manner. Meanwhile, suppression of PFKFB3 attenuated both the basal and Oxa-induced autophagy, by monitoring the autophagic flux and phosphorylated-Ulk1, which play essential roles in autophagy initiation. Moreover, PFKFB3 inhibition further inhibited the cell proliferation/migration, and cell viability decreased by Oxa. Collectively, the presented data demonstrated that PFKFB3 inhibition attenuated Oxa-induced autophagy and enhanced its cytotoxicity in colorectal cancer cells.

PPA1 promotes NSCLC progression via a JNK- and TP53-dependent manner.

Inorganic pyrophosphatase (PPA1) promotes tumor progression in several tumor types. However, the underlying mechanism remains elusive. Here, we disclosed that PPA1 expression is markedly upregulated in lung carcinoma tissue versus normal lung tissue. We also found that the non-small cell lung cancer (NSCLC) cell lines show increased PPA1 expression levels versus normal lung cell line control. Moreover, the knockdown of PPA1 promotes cell apoptosis and inhibits cell proliferation. Whereas, the ectopic expression of PPA1 reduces cell apoptosis and enhances cell proliferation. Most interestingly, the expression of mutant PPA1 (D117A) significantly abolishes PPA1-mediated effect on cell apoptosis and proliferation. The underlying mechanism demonstrated that TP53 expression deficiency or JNK inhibitor treatment could abolish PPA1-mediated NSCLC progression. In summary, the aforementioned findings in this study suggest a new pathway the PPA1 mediates NSCLC progression either via TP53 or JNK. Most important, the pyrophosphatase activity is indispensible for PPA1-mediated NSCLC progression. This may provide a promising target for NSCLC therapy.

Phenotypic characterization of malignant progenitor cells in patients with idiopathic myelofibrosis.

OBJECTIVE/BACKGROUND: Idiopathic myelofibrosis (IM) is a clonal hematological malignancy originating from pluripotent hematopoietic stem cells (HSC). HSC are very rare potent cells that reside in the bone marrow (BM) and at a lower level in peripheral blood (PB). Previous studies showed that IM PB CD34+ cells contain not only BM repopulating cells belonging to the malignant clone but also residual normal HSC. METHODS: In the current study, we separated the subpopulations of IM PB CD34+ cells using IL-3Rα/CD123 labeling and further characterized them by genetic and functional analyses. RESULTS: We differentiated IM PB CD34+ cells into three subpopulations (IL-3Rαhigh, IL-3Rαlow, and IL-3Rαnegative). IL-3Rαhigh CD34+ cell subgroup represents a small population in IM PB CD34+ cells which was not seen in normal G-CSF mobilized CD34+ cells. IM IL-3Rαhigh CD34+ cells contained significant higher percentage of cells bearing marker chromosome detected by fluorescence in situ hybridization (FISH) analysis. In the absence of growth factors, IM IL-3Rαhigh CD34+ cells exhibited abnormal colony forming ability and carried greater percentage of JAK2V617F mutant allele compared with IL-3Rαlow and IL-3Rαnegative CD34+ cells. CONCLUSION: These data indicate that IL-3Rαhigh CD34+ cells from IM enriched for the malignant progenitor cells and IL-3Rα/CD123 may be a potential biomarker and therapeutic target for IM. Our findings will be further validated in future studies with a larger sample size and serial transplant in murine models.

PRSS8 suppresses colorectal carcinogenesis and metastasis.

The serine protease PRSS8 has shown important physiological and pathological functions, but its roles in cancer initiation and progression are unclear. We developed and dynamically characterized a conditional knockout Prss8fl/fl, p-Villin-Cre+ mouse model. We found that genetic deficiency of the Prss8 gene caused spontaneous colitis and an inflamed rectum at an early age and caused intestinal tumors at a late age, which were linked to increased intestinal cell proliferation and migration but decreased cell differentiation. Increased PRSS8 expression inhibited cancer cell growth and metastasis in nude mice and inhibited cancer cell migration, invasion, colony formation and tumor sphere formation in vitro, but decreased PRSS8 expression facilitated malignancies in vivo and in vitro. Gene profiling on manipulated cancer cells and intestinal epithelial cells of Prss8 mouse models, gene set enrichment analysis and mechanistic studies revealed that PRSS8 targeted the Wnt/ß-catenin, epithelial-mesenchymal transition, and stem cell signaling pathways, which were further supported by the results from the TCGA data mining and validated by immunohistochemical staining on colorectal cancer tissue microarrays. In conclusion, PRSS8 is a novel tumor suppressor that plays critical roles in the suppression of colorectal carcinogenesis and metastasis.

The Dynamic Changes of Gut Microbiota in Muc2 Deficient Mice.

Gut dysbiosis is associated with colitis-associated colorectal carcinogenesis, and the genetic deficiency of the Muc2 gene causes spontaneous development of colitis and colorectal cancer. Whether there are changes of gut microbiota and a linkage between the changes of microbiota and intestinal pathology in Muc2-/- mice are unclear. Muc2-/- and Muc2+/+ mice were generated by backcrossing from Muc2+/- mice, and the fecal samples were collected at different dates (48th, 98th, 118th, 138th, and 178th day). Gut microbiota were analyzed by high-throughput sequencing with the universal 16S rRNA primers (V3⁻V5 region). All mice were sacrificed at day 178 to collect colonic tissue and epithelial cells for the analysis of histopathology and inflammatory cytokines. On the 178th day, Muc2-/- mice developed colorectal chronic colitis, hyperplasia, adenomas and adenocarcinomas, and inflammatory cytokines (e.g., cyclooxygenase 2 (COX-2), interleukin 6 (IL-6), tumor necrosis factor-α (TNF-α), interleukin 1 ß (IL-1ß), i-kappa-B-kinase ß (IKKß)) were significantly increased in colonic epithelial cells of Muc2-/- mice. In general, structural segregation of gut microbiota was observed throughout the experimental time points between the Muc2-/- and Muc2+/+ mice. Impressively, in Muc2-/- mice, Alpha diversities reflected by Shannon and Chao indexes were higher, the phylum of Firmicutes was enriched and Bacteroidetes was decreased, and Desulfovibrio, Escherichia, Akkermansia, Turicibacter, and Erysipelotrichaceae were significantly increased, but Lactobacilli and Lachnospiraceae were significantly decreased. Moreover, the abundance of Ruminococcaceae and butyrate-producing bacteria was significantly higher in the Muc2-/- mice. There were significant differences of gut microbiota between Muc2-/- and Muc2+/+ mice. The dynamic changes of microbiota might contribute to the development of colitis and colitis-associated colorectal carcinogenesis. Therefore, this study revealed specific functional bacteria in the development of colitis and colitis-associated colorectal carcinogenesis, which will benefit the development of preventive and therapeutic strategies for chronic inflammation and its malignant transformation.

Low dosage of arsenic trioxide (As2O3) inhibits angiogenesis in epithelial ovarian cancer without cell apoptosis.

Arsenic trioxide (As2O3) induces cell apoptosis and reduces the invasive and metastatic activities in various cancer types. However, the role of As2O3 in ovarian cancer angiogenesis remains unclear. In this study, we investigated the role of As2O3 in ovarian cancer angiogenesis and found that a low concentration of As2O3 causes no effects on epithelial ovarian cancer cell viability or apoptosis. Moreover, we found that As2O3-treated epithelial ovarian cancer cells demonstrate a reduced tube formation of endothelial cells in Matrigel. In addition, As2O3-treated epithelial ovarian cancer cells show a decreased VEGFA, VEGFR2 and CD31 mRNA expression. As per the underlying mechanisms involved in As2O3 treatment, we found that As2O3 inhibits VEGFA and VEGFR2 expression that thereby inhibits the VEGFA-VEGFR2-PI3K/ERK signaling pathway. This leads to a suppression in both VEGFA synthesis and angiogenesis-related gene expression. A decreased VEGFA synthesis and secretion also inhibits the VEGFA-VEGFR2-PI3K/ERK signaling pathway in human umbilical vein endothelial cells (HUVECs). In summary, our results may provide strategies for the use of As2O3 in the prevention of tumor angiogenesis.

Pregnancy-associated plasma protein a in cancer: expression, oncogenic functions and regulation.

Pregnancy-associated plasma protein A (PAPPA) is a protease that plays important roles in pregnancy, but interestingly acts as an oncogene outside of pregnancy. This review summarizes the oncogenic roles of PAPPA, including its expression levels in multiple malignancies, regulatory and signaling interactions, and pro-tumor functions, which include promoting tumor cell proliferation, invasion, migration and metastasis. These PAPPA activities are linked to IGFBP-4 proteolysis, increased IFG bioavailability, and activation of the NF-κB, PI3K/AKT and ERK signaling pathways. Therefore, PAPPA could be used as a biomarker for monitoring cancer development and progression as well as a potential therapeutic target.

Proline-Rich Protein Tyrosine Kinase 2 in Inflammation and Cancer.

Focal adhesion kinase (FAK) and its homologous FAK-related proline-rich tyrosine kinase 2 (Pyk2) contain the same domain, exhibit high sequence homology and are defined as a distinct family of non-receptor tyrosine kinases. This group of kinases plays critical roles in cytoskeletal dynamics and cell adhesion by regulating survival and growth signaling. This review summarizes the physiological and pathological functions of Pyk2 in inflammation and cancers. In particular, overexpression of Pyk2 in cancerous tissues is correlated with poor outcomes. Pyk2 stimulates multiple oncogenic signaling pathways, such as Wnt/ß-catenin, PI3K/Akt, MAPK/ERK, and TGF-ß/EGFR/VEGF, and facilitates carcinogenesis, migration, invasion, epithelial⁻mesenchymal transition and metastasis. Therefore, Pyk2 is a high-value therapeutic target and has clinical significance.

ICAM3 mediates tumor metastasis via a LFA-1-ICAM3-ERM dependent manner.

ICAM3 was reported to promote metastasis in tumors. However, the underlying mechanism remains elusive. Here, we disclosed that the expression of ICAM3 was closely correlated with the TNM stage of human breast and lung cancer, as well as the dominant overexpression in high aggressive tumor cell lines (231 and A549 cells). Moreover, the knockdown of ICAM3 inhibited tumor metastasis whereas the ectopic expression of ICAM3 promoted tumor metastasis both in vitro and in vivo. In addition, exploration of the underlying mechanism demonstrated that ICAM3 not only binds to LFA-1 with its extracellular domain and structure protein ERM but also to lamellipodia with its intracellular domain which causes a tension that pulls cells apart (metastasis). Furthermore, ICAM3 extracellular or intracellular mutants alternatively abolished ICAM3 mediated tumor metastasis in vitro and in vivo. As a therapy strategy, LFA-1 antibody or Lifitegrast restrained tumor metastasis via targeting ICAM3-LFA-1 interaction. In summary, the aforementioned findings suggest a model of ICAM3 in mediating tumor metastasis. This may provide a promising target or strategy for the prevention of tumor metastasis.

Sphingosine Kinase 1 and Sphingosine-1-Phosphate Signaling in Colorectal Cancer.

Sphingosine kinase 1 (Sphk1) is a highly conserved lipid kinase that phosphorylates sphingosine to form sphingosine-1-phosphate (S1P). Growing studies have demonstrated that Sphk1 is overexpressed in various types of solid cancers and can be induced by growth factors, cytokines, and carcinogens, leading to the increase of S1P production. Subsequently, the increased Sphk1/S1P facilitates cancer cell proliferation, mobility, angiogenesis, invasion, and metastasis. Therefore, Sphk1/S1P signaling plays oncogenic roles. This review summarizes the features of Sphk1/S1P signaling and their functions in colorectal cancer cell growth, tumorigenesis, and metastasis, as well as the possible underlying mechanisms.