V-akt Murine Thymoma Viral Oncogene Research Articles

D-dencichine Regulates Thrombopoiesis by Promoting Megakaryocyte Adhesion, Migration and Proplatelet Formation.

Life-threatening chemotherapy-induced thrombocytopenia can increase the risk of bleeding due to a dramatic low platelet count, which may limit or delay treatment schedules in cancer patients. The pressing need for the rapid alleviation of the symptoms of thrombocytopenia has prompted us to search for novel highly effective and safe thrombopoietic agents. Pharmacological investigations have indicated that dencichine can prevent and treat blood loss and increase the number of platelets. On the basis of the neurotoxicity of dencichine, D-dencichine is artificially synthesized in the laboratory. Our initial results showed that D-dencichine had potential to elevate peripheral platelet levels in mice with carboplatin-induced thrombocytopenia. However, the mechanisms of D-dencichine on thrombopoiesis have been poorly understood. In this study, we found that sequential administration of D-dencichine had a distinct ability to elevate numbers of reticulated platelets, and did not alter their clearance. Moreover, we demonstrated that D-dencichine was able to modulate the return of hematopoietic factors to normal levels, including thrombopoietin and IL-6. However, subsequent analysis revealed that D-dencichine treatment had no direct effects on megakaryocytes proliferation, differentiation, and polyploidization. Further in vitro studies, we demonstrated for the first time that D-dencichine significantly stimulated megakaryocyte adhesion, migration, and proplatelet formation in a dose-dependent manner through extracellular regulated protein kinases1/2 (ERK1/2) and v-akt murine thymoma viral oncogene homolog (AKT) signaling pathways. This study sufficiently characterized the role of the effects of D-dencichine treatment on the regulation of thrombopoiesis and provided a promising avenue for CIT treating.

Effects of MERTK Inhibitors UNC569 and UNC1062 on the Growth of Acute Myeloid Leukaemia Cells.

MER proto-oncogene tyrosine kinase (MERTK) is a receptor tyrosine kinase that affects cancer cell proliferation. This study evaluated the effects of the synthetic MERTK inhibitors UNC569 and UNC1062 on in vitro growth of acute myeloid leukaemia (AML) cells. Four AML cell lines expressing MERTK were treated with UNC569 and UNC1062 and analyzed for cell proliferation, immunoblotting, and gene expression. The effects of MERTK knockdown were also evaluated. Treatment with the inhibitors suppressed cell growth and induced apoptosis in all cell lines. OCI/AML5 and TMD7 cells, in which MERTK was constitutively phosphorylated by autocrine mechanisms, were highly susceptible to these inhibitors. The treatment reduced the phosphorylation of MERTK and its down-stream signalling molecules, v-akt murine thymoma viral oncogene homolog 1 (AKT) and extracellular signal-regulated kinase (ERK). Similar effects were observed after MERTK knockdown. The inhibitors and the knockdown caused similar changes in mRNA expression. These MERTK inhibitors are potential molecular-targeted drugs for treating AML expressing constitutively phosphorylated MERTK.

Ir-6: A Novel Iridium (III) Organometallic Derivative for Inhibition of Human Platelet Activation.

Platelet activation has been reported to play a major role in arterial thrombosis, cancer metastasis, and progression. Recently, we developed a novel Ir(III)-based compound, [Ir(Cp∗)1-(2-pyridyl)-3-(4-dimethylaminophenyl)imidazo[1,5-a]pyridine Cl]BF4 or Ir-6 and assessed its effectiveness as an antiplatelet drug. Ir-6 exhibited higher potency against human platelet aggregation stimulated by collagen. Ir-6 also inhibited ATP-release, intracellular Ca2+ mobilization, P-selectin expression, and the phosphorylation of phospholipase Cγ2 (PLCγ2), protein kinase C (PKC), v-Akt murine thymoma viral oncogene (Akt)/protein kinase B, and mitogen-activated protein kinases (MAPKs), in collagen-activated platelets. Neither the adenylate cyclase inhibitor SQ22536 nor the guanylate cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one significantly reversed the Ir-6-mediated inhibition of collagen-induced platelet aggregation. Moreover, Ir-6 did not considerably diminish OH radical signals in collagen-activated platelets or Fenton reaction solution. At 2 mg/kg, Ir-6 markedly prolonged the bleeding time in experimental mice. In conclusion, Ir-6 plays a crucial role by inhibiting platelet activation through the inhibition of signaling pathways, such as the PLCγ2–PKC cascade and the subsequent suppression of Akt and MAPK activation, thereby ultimately inhibiting platelet aggregation. Therefore, Ir-6 is a potential therapeutic agent for preventing or treating thromboembolic disorders or disrupting the interplay between platelets and tumor cells, which contributes to tumor cell growth and progression.

Comparative Analysis of V-Akt Murine Thymoma Viral Oncogene Homolog 3 (AKT3) Gene between Cow and Buffalo Reveals Substantial Differences for Mastitis

AKT3 gene is a constituent of the serine/threonine protein kinase family and plays a crucial role in synthesis of milk fats and cholesterol by regulating activity of the sterol regulatory element binding protein (SREBP). AKT3 is highly conserved in mammals and its expression levels during the lactation periods of cattle are markedly increased. AKT3 is highly expressed in the intestine followed by mammary gland and it is also expressed in immune cells. It is involved in the TLR pathways as effectively as proinflammatory cytokines. The aims of this study were to investigate the sequences differences between buffalo and cow. Our results showed that there were substantial differences between buffalo and cow in some exons and noteworthy differences of the gene size in different regions. We also identified the important consensus sequence motifs, variation in 2000 upstream of ATG, substantial difference in the “3′UTR” region, and miRNA association in the buffalo sequences compared with the cow. In addition, genetic analyses, such as gene structure, phylogenetic tree, position of different motifs, and functional domains, were performed to establish their correlation with other species. This may indicate that a buffalo breed has potential resistance to disease, environment changes, and airborne microorganisms and some good production and reproductive traits.

Breast cancer‐associated mitochondrial DNA haplogroup promotes neoplastic growth via ROS‐mediated AKT activation

In the last decade, mitochondrial DNA (mtDNA) haplogroups have been associated with the occurrence of breast cancer. However, the underlying mechanism is not known. Combining a case-control study with a large cohort of women from Southern China with breast cancer and functional analyses with trans-mitochondrial technology, we demonstrate that the D5 haplogroup is associated with an increased risk of breast cancer [odds ratio (OR) = 2.789; 95% confidence interval (CI) [1.318, 5.901]; p = 0.007]. Furthermore, mitochondrial respiration, mitochondrial ATP content and membrane potential, were lower in both bone osteosarcoma and breast cancer cell models of cytoplasmic hybrids (cybrids) containing the mtDNA D5 haplogroup than in those with non-D5 haplogroups. Using in vitro and in vivo tumorigenicity assays, we found that cells with the D5 haplogroup were more susceptible to tumorigenesis compared to cells with non-D5 haplogroups. Mechanistically, the D5 haplogroup may promote tumorigenesis at least partially through activation of the v-AKT murine thymoma viral oncogene (AKT) via phosphorylation of threonine 308, which is mediated by increased reactive oxygen species generation in D5 cybrids. Our findings demonstrate that there is decreased mitochondrial function in cells with the D5 haplogroup compared to cells with non-D5 haplogroups, which may be associated with increased neoplastic growth in breast cancer.

Suppressive activities and mechanisms of ugonin J on vascular smooth muscle cells and balloon angioplasty-induced neointimal hyperplasia.

Neointimal hyperplasia (or restenosis) is primarily attributed to excessive proliferation and migration of vascular smooth muscle cells (VSMCs). In this study, we investigated the inhibitory effects and mechanisms of ugonin J on VSMC proliferation and migration as well as neointimal formation. Cell viability and the cell-cycle distribution were, respectively, analyzed using an MTT assay and flow cytometry. Cell migration was examined using a wound-healing analysis and a transwell assay. Protein expressions and gelatinase activities were, respectively, measured using Western blot and gelatin zymography. Balloon angioplasty-induced neointimal formation was induced in a rat carotid artery model and then examined using immunohistochemical staining. Ugonin J induced cell-cycle arrest at the G0 /G1 phase and apoptosis to inhibit VSMC growth. Ugonin J also exhibited marked suppressive activity on VSMC migration. Ugonin J significantly reduced activations of focal adhesion kinase, phosphoinositide 3-kinase, v-akt murine thymoma viral oncogene homolog 1, and extracellular signal-regulated kinase 1/2 proteins. Moreover, ugonin J obviously reduced expressions and activity levels of matrix metalloproteinase-2 and matrix metalloproteinase-9. In vivo data indicated that ugonin J prevented balloon angioplasty-induced neointimal hyperplasia. Our study suggested that ugonin J has the potential for application in the prevention of balloon injury-induced neointimal formation.

Genome-wide mapping of estrogen receptor α binding sites by ChIP-seq to identify genes related to sexual maturity in hens

In ovarian follicle development, estrogen acts as a regulatory molecule to mediate proliferation and differentiation of follicular cells. ERα (estrogen receptor α) exerts regulatory function classically by binding directly to the estrogen response element, recruiting co-factors and activating or repressing transcription in response to E2. In this study, we used ChIP-seq to map ERα-binding sites in ovaries of Hy-line Brown commercial hens at 45d, 90d and 160d. In total, 24,886, 21,680 and 23,348 binding sites were identified in the ovaries of hens at 45d, 90d and 160d, which are linked to 86, 83 and 74 genes, respectively. The PPI network contains 47 protein nodes and 164 interaction edges, among which, AKT1 (V-Akt Murine Thymoma Viral Oncogene Homolog 1) and ACTN2 (Actinin Alpha 2) with the highest weight in the network, followed by CREB1 (CAMP Responsive Element Binding Protein 1), and EPHA5 (EPH Receptor A5) were identified. These genes are likely related to sexual maturity in hens. This study also provides insight into the regulation of the ERα target gene networks and a reference for understanding ERα-regulated transcription.

Research Advances of Calcium-and Integrin-binding Protein 1 in Tumors.

Calcium-and integrin-binding protein 1(CIB1),a member of calcium binding protein containing EF-hand domain,has been shown to bind a variety of signaling proteins. Interaction of CIB1 with its various binding partners provides valuable insight into potential mechanisms by which CIB1 may regulate diverse tumors characteristic biological process that range from adhesion,migration,cell survival,proliferation,and angiogenesis. CIB1 has also been implicated in both the increase and decrease of cell proliferation.CIB1 promoted cell proliferation and survival by adjusted tumor-associated extracellular regulated protein kinases 1/2(ERK1/2),phosphatidylinositol 3 kinase(PI-3K)/v-akt murine thymoma viral oncogene homolog-dependent signaling pathway,or increased cell migration by activating Src family kinases,protein kinase C,PI-3K,and ERK 1/2-mediated signaling pathway.CIB1 inhibited cell proliferation through inhibiting polo-like kinases 3(PLK3) activity.It also inhibits cell migration by binding to and activating p21-activated kinase 1. Especially a large subset of triple-negative breast cancer may display non-oncogene addiction to CIB1,a phenomenon in which cancer cells require,or become 'addicted' to a non-mutated,non-overexpressed gene/protein that is nonetheless essential to maintain oncogenic signaling pathways,and implicate CIB1 as a novel drug target in tumors. Additionally,CIB1 plays a role in such pathological processes as cardiac hypertrophy,deafness,and male infertility. Research on CIB1 function has important clinical significance. In this review,we discussed current understanding of CIB1 in human tumors.

MicroRNA-206 prevents the pathogenesis of hepatocellular carcinoma by modulating expression of met proto-oncogene and cyclin-dependent kinase 6 in mice.

In summary, this study defines a potentially critical role of microRNA-206 in preventing the growth of HCC and suggests its use as a potential therapeutic strategy for this malignancy. (Hepatology 2017;66:1952-1967).

A maternal high-fat, high-sucrose diet alters insulin sensitivity and expression of insulin signalling and lipid metabolism genes and proteins in male rat offspring: effect of folic acid supplementation.

A maternal high-fat, high-sucrose (HFS) diet alters offspring glucose and lipid homoeostasis through unknown mechanisms and may be modulated by folic acid. We investigated the effect of a maternal HFS diet on glucose homoeostasis, expression of genes and proteins associated with insulin signalling and lipid metabolism and the effect of prenatal folic acid supplementation (HFS/F) in male rat offspring. Pregnant Sprague-Dawley rats were randomly fed control (CON), HFS or HFS/F diets. Offspring were weaned on CON; at postnatal day 70, fasting plasma insulin and glucose and liver and skeletal muscle gene and protein expression were measured. Treatment effects were assessed by one-way ANOVA. Maternal HFS diet induced higher fasting glucose in offspring v. HFS/F (P=0·027) and down-regulation (P<0·05) of genes coding for v-Akt murine thymoma viral oncogene homolog 2, resistin and v-Raf-1 murine leukaemia viral oncogene homolog 1 (Raf1) in offspring skeletal muscle and acetyl-CoA carboxylase (Acaca), fatty acid synthase and phosphatidylinositol-4,5-biphosphate 3-kinase, catalytic subunit β in offspring liver. Skeletal muscle neuropeptide Y and hepatic Kruppel-like factor 10 were up-regulated in HFS v. CON offspring (P<0·05). Compared with CON, Acaca and Raf1 protein expression levels were significantly lower in HFS offspring. Maternal HFS induced higher homoeostasis model of assessment index of insulin resistance v. CON (P=0·030) and HFS/F was associated with higher insulin (P=0·016) and lower glucose (P=0·025). Maternal HFS diet alters offspring insulin sensitivity and de novo hepatic lipogenesis via altered gene and protein expression, which appears to be potentiated by folate supplementation.

Herbacetin suppresses cutaneous squamous cell carcinoma and melanoma cell growth by targeting AKT and ODC.

Herbacetin is a flavonol compound that is found in plants such as flaxseed and ramose scouring rush herb, it possesses a strong antioxidant capacity, and exerts anticancer effects on colon and breast cancer. However, the effect of herbacetin on skin cancer has not been investigated. Herein, we identified herbacetin as a dual V-akt murine thymoma viral oncogene homolog (AKT) and ornithine decarboxylase (ODC) inhibitor, and illustrated its anticancer effects in vitro and in vivo against cutaneous squamous cell carcinoma (SCC) and melanoma cell growth. To identify the direct target(s) of herbacetin, we screened several skin cancer-related protein kinases, and results indicated that herbacetin strongly suppresses both AKT and ODC activity. Results of cell-based assays showed that herbacetin binds to both AKT and ODC, inhibits TPA-induced neoplastic transformation of JB6 mouse epidermal cells, and suppresses anchorage-independent growth of cutaneous SCC and melanoma cells. The inhibitory activity of herbacetin was associated with markedly reduced NF-κB and AP1 reporter activity. Interestingly, herbacetin effectively attenuated TPA-induced skin cancer development and also exhibited therapeutic effects against solar-UV-induced skin cancer and melanoma growth in vivo. Our findings indicate that herbacetin is a potent AKT and ODC inhibitor that should be useful for preventing skin cancers.

Human trophoblast-derived hydrogen sulfide stimulates placental artery endothelial cell angiogenesis.

Endogenous hydrogen sulfide (H2S), mainly synthesized by cystathionine β-synthase (CBS) and cystathionine γ-lyase (CTH), has been implicated in regulating placental angiogenesis; however, the underlying mechanisms are unknown. This study was to test a hypothesis that trophoblasts synthesize H2S to promote placental angiogenesis. Human choriocarcinoma-derived BeWo cells expressed both CBS and CTH proteins, while the first trimester villous trophoblast-originated HTR-8/SVneo cells expressed CTH protein only. The H2S producing ability of BeWo cells was significantly inhibited by either inhibitors of CBS (carboxymethyl hydroxylamine hemihydrochloride, CHH) or CTH (β-cyano-L-alanine, BCA) and that in HTR-8/SVneo cells was inhibited by CHH only. H2S donors stimulated cell proliferation, migration, and tube formation in ovine placental artery endothelial cells (oFPAECs) as effectively as vascular endothelial growth factor. Co-culture with BeWo and HTR-8/SVneo cells stimulated oFPAEC migration, which was inhibited by CHH or BCA in BeWo but CHH only in HTR-8/SVneo cells. Primary human villous trophoblasts (HVT) were more potent than trophoblast cell lines in stimulating oFPAEC migration that was inhibited by CHH and CHH/BCA combination in accordance with its H2S synthesizing activity linked to CBS and CTH expression patterns. H2S donors activated endothelial nitric oxide synthase (NOS3), v-AKT murine thymoma viral oncogene homolog 1 (AKT1), and extracellular signal-activated kinase 1/2 (mitogen-activated protein kinase 3/1, MAPK3/1) in oFPAECs. H2S donor-induced NOS3 activation was blocked by AKT1 but not MAPK3/1 inhibition. In keeping with our previous studies showing a crucial role of AKT1, MAPK3/1, and NOS3/NO in placental angiogenesis, these data show that trophoblast-derived endogenous H2S stimulates placental angiogenesis, involving activation of AKT1, NOS3/NO, and MAPK3/1.

Synthesis and anti-diabetic activity of new N,N-dimethylphenylenediamine-derivatized nitrilotriacetic acid vanadyl complexes

Vanadium compounds are promising anti-diabetic agents. However, reducing the metal toxicity while keeping/improving the hypoglycemic effect is still a big challenge towards the success of anti-diabetic vanadium drugs. To improve the therapeutic potency using the anti-oxidative strategy, we synthesized new N,N-dimethylphenylenediamine (DMPD)-derivatized nitrilotriacetic acid vanadyl complexes ([VO(dmada)]). The in vitro biological evaluations revealed that the DMPD-derivatized complexes showed improved antioxidant capacity and lowered cytotoxicity on HK-2 cells than bis(maltolato)oxidovanadium (IV) (BMOV). In type II diabetic mice, [VO(p-dmada)] (0.15mmolkg−1/day) exhibited better hypoglycemic effects than BMOV especially on improving glucose tolerance and alleviating the hyperglycemia-induced liver damage. These insulin enhancement effects were associated with increased expression of peroxisome proliferator-activated receptor α and γ (PPARα/γ) in fat, activation of Akt (v-Akt murine thymoma viral oncogene)/PKB (protein kinase-B) in fat and liver, and inactivation of c-Jun NH2-terminal protein kinases (JNK) in liver. Moreover, [VO(p-dmada)] showed no tissue toxicity at the therapeutic dose in diabetic mice and the oral acute toxicity (LD50) was determined to be 1640mgkg−1. Overall, the experimental results indicated that [VO(p-dmada)] can be a potent insulin enhancement agent with improved efficacy-over- toxicity index for further drug development. In addition, the results on brain Tau phosphorylation suggested necessary investigation on the effects of vanadyl complexes on the pathology of the Alzheimer's disease in the future.

SNPs, linkage disequilibrium, and chronic mountain sickness in Tibetan Chinese.

Chronic mountain sickness (CMS) is estimated at 1.2% in Tibetans living at the Qinghai–Tibetan Plateau. Eighteen single-nucleotide polymorphisms (SNPs) from nine nuclear genes that have an association with CMS in Tibetans have been analyzed by using pairwise linkage disequilibrium (LD). The SNPs included are the angiotensin-converting enzyme (rs4340), the angiotensinogen (rs699), and the angiotensin II type 1 receptor (AGTR1) (rs5186) from the renin–angiotensin system. A low-density lipoprotein apolipoprotein B (rs693) SNP was also included. From the hypoxia-inducible factor oxygen signaling pathway, the endothetal Per-Arnt-Sim domain protein 1 (EPAS1) and the egl nine homolog 1 (ENGL1) (rs480902) SNPs were included in the study. SNPs from the vascular endothelial growth factor (VEGF) signaling pathway included are the v-akt murine thymoma viral oncogene homolog 3 (rs4590656 and rs2291409), the endothelial cell nitric oxide synthase 3 (rs1007311 and rs1799983), and the (VEGFA) (rs699947, rs34357231, rs79469752, rs13207351, rs28357093, rs1570360, rs2010963, and rs3025039). An increase in LD occurred in 40 pairwise comparisons, whereas a decrease in LD was found in 55 pairwise comparisons between the controls and CMS patients. These changes were found to occur within and between signaling pathways, which suggests that there is an interaction between SNP alleles from different areas of the genome that affect CMS.

Critical role of β1 integrin in postnatal beta-cell function and expansion.

β1 integrin is essential for pancreatic beta-cell development and maintenance in rodents and humans. However, the effects of a temporal beta-cell specific β1 integrin knockout on adult islet function are unknown. We utilized a mouse insulin 1 promoter driven tamoxifen-inducible Cre-recombinase β1 integrin knockout mouse model (MIPβ1KO) to investigate β1 integrin function in adult pancreatic beta-cells. Adult male MIPβ1KO mice were significantly glucose intolerant due to impaired glucose-stimulated insulin secretion in vivo and ex vivo at 8 weeks post-tamoxifen. The expression of Insulin and Pancreatic and duodenal homeobox-1 mRNA was significantly reduced in MIPβ1KO islets, along with reductions in insulin exocytotic proteins. Morphological analyses demonstrated that beta-cell mass, islet density, and the number of large-sized islets was significantly reduced in male MIPβ1KO mice. Significant reductions in the phosphorylation of signaling molecules focal adhesion kinase, extracellular signal-regulated kinases 1 and 2, and v-Akt murine thymoma viral oncogene were observed in male MIPβ1KO islets when compared to controls. MIPβ1KO islets displayed a significant increase in protein levels of the apoptotic marker cleaved-Poly (ADP-ribose) polymerase and a reduction of the cell cycle marker cyclin D1. Female MIPβ1KO mice did not develop glucose intolerance or reduced beta-cell mass until 16 weeks post-tamoxifen. Glucose intolerance remained in both genders of aged MIPβ1KO mice. This data demonstrates that β1 integrin is required for the maintenance of glucose homeostasis through postnatal beta-cell function and expansion.

Role of G3BP1 in glucocorticoid receptor-mediated microRNA-15b and microRNA-23a biogenesis in endothelial cells.

MicroRNAs (miRNAs) are a family of non-coding RNAs that play crucial roles in regulating various normal cellular responses. Recent studies revealed that the canonical miRNA biogenesis pathway is subject to sophisticated regulation. Hormonal control of miRNA biogenesis by androgen and estrogen has been demonstrated, but the direct effects of the glucocorticoid receptor (GR) on miRNA biogenesis are unknown. This study revealed the role of GR in miRNA maturation. We showed that two GR agonists, dexamethasone and ginsenoside-Rg1 rapidly suppressed the expression of mature miR-15b, miR-23a, and miR-214 in human endothelial cells. RNA pulldown coupled with proteomic analysis identified GTPase-activating protein (SH3 domain) binding protein 1 (G3BP1) as one of the RNA-binding proteins mediating GR-regulated miRNA maturation. Activated GR induced phosphorylation of v-AKT Murine Thymoma Viral Oncogene Homologue (AKT) kinase, which in turn phosphorylated and promoted nuclear translocation of G3BP1. The nuclear G3BP1 bound to the G3BP1 consensus sequence located on primary miR-15b~16-2 and miR-23a~27a~24-2 to inhibit their maturation. The findings from this study have advanced our understanding of the non-genomic effects of GR in the vascular system.

Prediction of a highly deleterious mutation E17K in AKT-1 gene: An in silico approach

The AKT1 (v-akt murine thymoma viral oncogene homologue 1) kinase is a member of most frequently activated proliferation and survival signaling pathway in cancer. Recently, hyperactivation of AKT1, due to functional point mutation in the pleckstrin homology (PH) domain of AKT1 gene, has been found to be associated with human colorectal, breast and ovarian cancer. Thus, considering its crucial role in cellular signaling pathway, a functional analysis of missense mutations of AKT1 gene was undertaken in this study. Twenty nine nsSNPs (non-synonymous single nucleotide polymorphism) within coding region of AKT1 gene were selected for our investigation and six SNPs were found to be deleterious by combinatorial predictions of various computational tools. RMSD values were calculated for the mutant models which predicted four substitutions (E17K, E319G, D32E and A255T) to be highly deleterious. The insight of the structural attribute was gained through analysis of, secondary structures, solvent accessibility and intermolecular hydrogen bond analysis which confirmed one missense mutation (E17K) to be highly deleterious nsSNPs. In conclusion, the investigated gene AKT1 has twenty nine SNPs in the coding region and through progressive analysis using different bioinformatics tools one highly deleterious SNP with rs121434592 was profiled. Thus, results of this study can pave a new platform to sort nsSNPs for several important regulatory genes that can be undertaken for the confirmation of their phenotype and their correlation with diseased status in case control studies.

Inhibition of HSF1 suppresses the growth of hepatocarcinoma cell lines in vitro and AKT-driven hepatocarcinogenesis in mice.

Upregulation of the heat shock transcription factor 1 (HSF1) has been described as a frequent event in many cancer types, but its oncogenic role in hepatocellular carcinoma (HCC) remains poorly delineated. In the present study, we assessed the function(s) of HSF1 in hepatocarcinogenesis via in vitro and in vivo approaches. In particular, we determined the importance of HSF1 on v-Akt murine thymoma viral oncogene homolog (AKT)-induced liver cancer development in mice. We found that knockdown of HSF1 activity via specific siRNA triggered growth restraint by suppressing cell proliferation and inducing massive cell apoptosis in human HCC cell lines. At the molecular level, HSF1 inhibition was accompanied by downregulation of the phosphoinositide 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) cascade and related metabolic pathways. Most importantly, overexpression of a dominant negative form of HSF1 (HSF1dn) in the mouse liver via hydrodynamic gene delivery led to the inhibition of mouse hepatocarcinogenesis driven by overexpression of AKT. In human liver cancer specimens, we detected that HSF1 is progressively induced from human non-tumorous surrounding livers to HCC, reaching the highest expression in the tumors characterized by the poorest outcome (as defined by the length of patients’ survival). In conclusion, HSF1 is an independent prognostic factor in liver cancer and might represent an innovative therapeutic target in HCC subsets characterized by activation of the AKT/mTOR pathway.

P53/microRNA-374b/AKT1 regulates colorectal cancer cell apoptosis in response to DNA damage.

Colorectal cancer (CRC) has a rising morbidity worldwide and its resistance to chemotherapy has been observed in clinical treatment. Tumor suppressor p53 is well-studied in CRC, but little is known about its effects during DNA damage of CRC cells. This study was aimed at uncovering potential mechanisms of p53 regarding microRNA-374b and v-akt murine thymoma viral oncogene homolog1 (AKT1) during DNA damage of CRC cells. CRC cells HCT116 and HT29 were transfected with p53-specific small interfering RNA (siRNA), p53 overexpression vector or miR-374b inhibitor, and then treated with 10µM bleomycin (BLM) for 24h to induce DNA damage. Primary (pri), precursor (pre) and mature miR-374b levels were quantified by qRT-PCR. AKT1 and p53 protein levels were detected by western blotting. Cell apoptosis changes were assessed by flow cytometry. AKT1 mRNA was detected to be induced by BLM treatment (P<0.05), but its protein level was strongly inhibited. Knockdown of p53 reversed the inhibition of AKT1 protein by BLM. Overexpression of p53 in p53-knockout HCT116 and HT29 cells upregulated the AKT1 regulator miR-374b (P<0.05), and knockdown of p53 reversed the induction of miR-374b by BLM. qRT-PCR suggested that besides mature miR-374b, p53 could also promote pre-miR-374b level (P<0.05), rather than pri-miR-374b. Moreover, inhibition on miR-374b relieved the suppressed AKT1 protein, and reduced cell apoptosis induced by BLM. These data depict the p53/miR-374b/AKT1 signaling that may regulate BLM-induced apoptosis in CRC cells, thus facilitating to improve the outcome of chemotherapy in CRC.

The Addition of Liquid Fructose to a Western-Type Diet in LDL-R-/- Mice Induces Liver Inflammation and Fibrogenesis Markers without Disrupting Insulin Receptor Signalling after an Insulin Challenge.

A high consumption of fat and simple sugars, especially fructose, has been related to the development of insulin resistance, but the mechanisms involved in the effects of these nutrients are not fully understood. This study investigates the effects of a Western-type diet and liquid fructose supplementation, alone and combined, on insulin signalling and inflammation in low-density lipoprotein (LDL) receptor-deficient mice (LDL-R−/−). LDL-R−/− mice were fed chow or Western diet ±15% fructose solution for 12 weeks. Plasma glucose and insulin, and the expression of genes related to inflammation in the liver and visceral white adipose tissue (vWAT), were analysed. V-akt murine thymoma viral oncogene homolog-2 (Akt) activation was measured in the liver of the mice after a single injection of saline or insulin. None of the dietary interventions caused inflammation in vWAT, whereas the Western diet induced hepatic inflammation, which was further enhanced by liquid fructose, leading also to a significant increase in fibrogenesis markers. However, there was no change in plasma glucose or insulin, or insulin-induced Akt phosphorylation. In conclusion, hepatic inflammation and fibrogenesis markers induced by a Western diet supplemented with liquid fructose in LDL-R−/− mice are not associated with a significant impairment of hepatic insulin signalling.