Effects of hypoxia-inducible factor-1α silencing on the proliferation of CBRH-7919 hepatoma cells

Systemic Delivery of Magnetogene Nanoparticle Vector for Gene Expression in Hypoxic Tumors

Cancer is a disease that causes millions of deaths per year worldwide because conventional treatments have disadvantages such as unspecific tumor selectivity and unwanted toxicity. Most human solid tumors present hypoxic microenvironments and this promotes multidrug resistance. In this study, we present "Magnetogene nanoparticle vector" which takes advantage of the hypoxic microenvironment of solid tumors to increase selective gene expression in tumor cells and reduce unwanted toxicity in healthy cells; this vector was guided by a magnet to the tumor tissue. Magnetic nanoparticles (MNPs), chitosan (CS), and the pHRE-Luc plasmid with a hypoxia-inducible promoter were used to synthesize the vector called "Magnetogene nanoparticles" by ionic gelation. The hypoxic functionality of Magnetogene vector nanoparticles was confirmed in the B16F10 cell line by measuring the expression of the luciferase reporter gene under hypoxic and normoxic conditions. Also, the efficiency of the Magnetogene vector was confirmed in vivo. Magnetogene was administered by intravenous injection (IV) in the tail vein and directed through an external magnetic field at the site of tumor growth in C57Bl/6 mice. A Magnetogene vector with a size of 50 to 70 nm was directed and retained at the tumor area and gene expression was higher at the tumor site than in the others tissues, confirming the selectivity of this vector towards hypoxic tumor areas. This nanosystem, that we called the "Magnetogene vector" for systemic delivery and specific gene expression in hypoxic tumors controlled by an external magnetic designed to target hypoxic regions of tumors, can be used for cancer-specific gene therapies.

LY‑294002 enhances the chemosensitivity of liver cancer to oxaliplatin by blocking the PI3K/AKT/HIF‑1α pathway

Liver cancer remains one of the leading causes of cancer deaths worldwide. The therapeutic effect of oxaliplatin on liver cancer is often limited by acquired resistance of the cancer cells. Abnormal activation of the PI3K/AKT pathway plays an important role in the acquired resistance of oxaliplatin. The present study investigated the effects of the PI3K inhibitor LY-294002 and AKT inhibitor MK2206 on the chemosensitivity of oxaliplatin-resistant liver cancer cells and the molecular mechanism involved. An oxaliplatin-resistant liver cancer cell line HepG2^R was developed. MTT assay, clone formation experiments, flow cytometry and Annexin V-FITC/PI staining were used to determine the proliferation, cycle and apoptosis of HepG2^R cells when oxaliplatin was combined with LY-294002 or MK2206 treatment. The effects of LY-294002 and MK-2206 on the abnormal activation of PI3K/AKT pathway and hypoxia inducible factor (HIF)-1α protein level in HepG2^R cells were detected using western blotting. The results indicated that the PI3K/AKT pathway is stably activated in HepG2^R cells. Compared with the AKT inhibitor MK2206, the PI3K inhibitor LY-294002 more effectively downregulated the phosphorylation levels of p85, p110α, p110β, p110γ and AKT in the PI3K/AKT pathway in HepG2^R cells, and more effectively inhibited the proliferation of the cells. LY-294002 enhanced the chemotherapy sensitivity of HepG2^R cells to oxaliplatin by inducing G₀/G₁ phase arrest and increasing the proportion of apoptotic cells. In addition, LY-294002 reduced the level of HIF-1α, which is highly expressed in HepG2^R cells. It was concluded that LY-294002 enhanced the chemosensitivity of liver cancer cells to oxaliplatin by inhibiting the PI3K/AKT signaling pathway, which may be related to the inhibition of HIF-1α expression. These findings may have clinical significance for the treatment of oxaliplatin-resistant liver cancer.

Systems Pharmacology-Based Identification of Mechanisms of Action of Bolbostemma paniculatum for the Treatment of Hepatocellular Carcinoma

Background

Traditional Chinese medicine has widely used Bolbostemma paniculatum to treat diseases, including cancer, but its underlying mechanisms remain unclear. The present study aimed to elucidate the potential pharmacological mechanisms of “Tu Bei Mu” (TBM), the Chinese name for Bolbostemmatis Rhizoma, the dry tuber of B. paniculatum, for the treatment of hepatocellular carcinoma (HCC).

Material/Methods

The active components and putative therapeutic targets of TBM were explored using SwissTargetPrediction, Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform (TCMSP), and Search Tool for Interactions of Chemicals (STITCH). The HCC-related target database was built using DrugBank, DisGeNet, Online Mendelian Inheritance in Man (OMIM), and Therapeutic Target Database (TTD). A protein–protein interaction network of the common targets was constructed, based on the matches between TBM potential targets and HCC-related targets, using Cytoscape software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of the cluster networks were used to elucidate the biological functions of TBM.

Results

Pharmacological network diagrams of the TBM compound-target network and HCC-related target network were successfully constructed. A total of 22 active components, 191 predicted biological targets of TBM, and 3775 HCC-related targets were identified. Through construction of an HCC-related target database and a protein–protein interaction network of the common targets, TBM was predicted to be effective in treating HCC mainly through the PI3K-Akt, HIF-1, p53, and PPAR signaling pathways.

Conclusions

The PI3K/Akt, HIF1, p53, and PPAR pathways may play vital roles in TBM treatment of HCC. Also, the potential anti-cancer effect of TBM on HCC appears to stem from the synergetic effect of multiple targets and mechanisms.

Prognostic Factors for Survival After Transarterial Chemoembolization Combined with Sorafenib in the Treatment of BCLC Stage B and C Hepatocellular Carcinomas

RATIONALE AND OBJECTIVE

The objective of this study was to analyze prognostic factors for survival after transarterial chemoembolization (TACE) combined with sorafenib for hepatocellular carcinoma (HCC) of Barcelona Clinic Liver Cancer (BCLC) stages B and C.

MATERIALS AND METHODS

Clinical data of 198 patients with BCLC stage B and C HCCs who underwent TACE combined with sorafenib between June 2012 and January 2017 were retrospectively collected and analyzed. Survival curves were detected using log-rank test. Univariate analysis was performed using log-rank test with respect to 11 prognostic factors potentially affecting survival. All statistically significant prognostic factors identified by univariate analysis were entered into a Cox proportion hazards regression model to identify independent predictors of survival. P values were two-sided and P < 0.05 was considered statistically significant.

RESULTS

By the end of this study, the median follow-up duration was 43.6 months. The median overall survival (OS) of the patients was 21.0 months (95% confidence interval [CI]: 16.94-25.05), and the 1-, 2-, 3- and 5-year OS rates were 72%, 43%, 28%, and 4%, respectively. Tumor size (χ² = 33.607, P < 0.0001), tumor number (χ² = 4.084, P = 0.043), Child-Pugh class (χ² = 33.187, P < 0.0001), BCLC stage (χ² = 50.224, P < 0.0001), portal vein tumor thrombus (χ² = 88.905, P < 0.0001), Eastern Cooperative Oncology Group (ECOG) performance status (χ² = 98.007, P < 0.0001), extrahepatic spread (χ² = 34.980, P < 0.0001), TACE times (χ² = 8.350, P = 0.015), and sorafenib treatment strategy (χ² = 81.593, P < 0.0001) were found to be significantly associated with OS by univariate analysis. Multivariate analysis showed that BCLC stage (95% CI: 1.133-3.982, P = 0.019), extrahepatic spread (95% CI: 1.136-2.774, P = 0.012), and sorafenib treatment duration (95% CI: 0.352-0.574, P = 0.000) were independent prognostic factors associated with OS. There were no serious treatment-related adverse events.

CONCLUSIONS

This study showed that extrahepatic spread was a risk factor, and sorafenib treatment and superior BCLC stage were protective factors. Therefore, the study indicated that TACE combined with sorafenib was an effective and safe treatment for patients with BCLC stage B HCC without extrahepatic spread.

Lentivirus‑mediated MDA7/IL24 expression inhibits the proliferation of hepatocellular carcinoma cells

MDA7/IL24 is a member of the IL-10 gene family that functions as a cytokine. Notably, supra-physiological endogenous MDA7 levels have been indicated to suppress tumor growth and induce apoptosis in different cancer types. In the present study, MDA7 roles were investigated during the proliferation of hepatocellular carcinoma (HCC) cells and the molecular mechanisms underlying this process. A lentiviral vector expressing MDA7/IL24 (LV-MDA7/IL24) was constructed and used to infect HCC SMMC-7721 cells. The expression levels of MDA7/IL24 in these cells were determined using RT-qPCR and western blot analysis. The effects of LV-MDA7/IL24 on cell proliferation were analyzed using MTT and colony formation assays. Furthermore, the influence of LV-MDA7/IL24 on cell apoptosis and cell cycle distribution were detected using flow cytometry. The underlying molecular mechanisms were investigated using microarray and western blot analysis. The expression of MDA7/IL24 was confirmed to be significantly increased in the cells infected with LV-MDA7/IL24 compared with that the negative-control infected group. Lentivirus-mediated MDA7/IL24 expression was found to inhibit HCC cell proliferation and colony formation, and it also induced cell arrest and apoptosis. Microarray analysis and western blotting results indicated that multiple cancer-associated pathways and oncogenes are regulated by MDA7/IL24, including cell cycle regulatory and apoptosis activation pathway. In conclusion, it was determined that MDA7/IL24 inhibits the proliferation and reduces the tumorigenicity of HCC cells by regulating cell cycle progression and inducing apoptosis, indicating that it may be used as a potential prognostic and therapeutic target in HCC.

Resveratrol improves alcoholic fatty liver disease by downregulating HIF-1α expression and mitochondrial ROS production

Oxidative stress has been demonstrated to be involved in the etiology of alcoholic fatty liver disease (AFLD). Previous studies had demonstrated that resveratrol (RES) could reduce oxidative stress by different mechanisms. However, the effect of RES on alcohol-induced fatty liver remains unclear. In the present study, a total of 48 male SD rats were divided into three groups: Control, AFLD, and RES groups. Rats were administered with either nothing or 65% vol/vol alcohol (5 ml/kg/day in the first three days, and then 10 ml/kg/day in the following days) with or without RES supplementation (250 mg/kg/day) for 4 weeks. Blood and liver tissue samples were collected and subjected to biochemical assays, histological examination, Western blot, and mitochondrial radical oxygen species (ROS) assays. In RES group, significant decreases in serum ALT and AST concentrations, fat deposition, triglyceride (TG) content, HIF-1α protein expression as well as mitochondrial ROS production in liver were observed when compared with AFLD group (all p <0.05). These results indicated that RES could alleviate the liver injury induced by alcohol and prevent the progression of AFLD. Down regulation of HIF-1α protein expression and mitochondrial ROS production in liver might be, at least part of, the underlying mechanisms.

Transarterial embolization combined with RNA interference targeting hypoxia-inducible factor-1α for hepatocellular carcinoma: a preliminary study of rat model

PURPOSE

To study whether transarterial embolization (TAE) with RNA interference (RNAi) targeting hypoxia-inducible factor-1α (HIF-1α) can improve efficacy of TAE in treating hepatocellular carcinoma (HCC).

MATERIALS AND METHODS

CBRH-7919 rat hepatoma cell line was used and HCC models of rats were constructed. The siRNA transfection compound was made by mixing specific siRNA and Lipofectamine 2000™. Delivery and transfection of siRNA were administered by injecting iodized oil emulsion (diluted lipiodol and siRNA) via hepatic artery. The expression levels of mRNA and protein were detected using the real-time reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry and western blotting assays, respectively.

RESULTS

In vitro experiment, the specific HIF-1α-siRNA was proved to inhibit expression levels of HIF-1α and vascular endothelial growth factor (VEGF) effectively. In animal study, real-time RT-PCR assay showed the average relative mRNA expressions of HIF-1α were 0.31 ± 0.01, 0.65 ± 0.03, 0.46 ± 0.005, and 1.00 ± 0.00 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Western blotting assay showed the average relative protein expressions of HIF-1α were 0.13 ± 0.02, 0.87 ± 0.02, 0.39 ± 0.02, and 1.02 ± 0.01 in TAE + siRNA, siRNA, TAE, and control groups, respectively. Compared with control, TAE, and siRNA groups, TAE + siRNA can significantly inhibit protein expressions of HIF-1α and VEGF (P HIF-1α < 0.001; P VEGF < 0.001). Overall survival of rats underwent TAE + siRNA was significantly longer than that of rats treated with TAE monotherapy (P = 0.001).

CONCLUSION

This animal study showed TAE combined with HIF-1α-RNAi could significantly improve efficacy of TAE in treating HCC by inhibiting expressions of HIF-1α and VEGF after TAE treatment.

A tumoural angiogenic gateway blocker, Benzophenone-1B represses the HIF-1α nuclear translocation and its target gene activation against neoplastic progression

Hypoxia is an important module in all solid tumours to promote angiogenesis, invasion and metastasis. Stabilization and subsequent nuclear localization of HIF-1α subunits result in the activation of tumour promoting target genes such as VEGF, MMPs, Flt-1, Ang-1 etc. which plays a pivotal role in adaptation of tumour cells to hypoxia. Increased HIF-α and its nuclear translocation have been correlated with pronounced angiogenesis, aggressive tumour growth and poor patient prognosis leading to current interest in HIF-1α as an anticancer drug target. Benzophenone-1B ([4-(1H-benzimidazol-2-ylmethoxy)-3,5-dimethylphenyl]-(4-methoxyphenyl) methanone, or BP-1B) is a new antineoplastic agent with potential angiopreventive effects. Current investigation reports the cellular biochemical modulation underlying BP-1B cytotoxic/antiangiogenic effects. Experimental evidences postulate that BP-1B exhibits the tumour specific cytotoxic actions against various cancer types with prolonged action. Moreover BP-1B efficiently counteracts endothelial cell capillary formation in in-vitro, in-vivo non-tumour and tumour angiogenic systems. Molecular signaling studies reveal that BP-1B arrests nuclear translocation of HIF-1α devoid of p42/44 pathway under CoCl₂ induced hypoxic conditions in various cancer cells thereby leading to abrogated HIF-1α dependent activation of VEGF-A, Flt-1, MMP-2, MMP -9 and Ang-1 angiogenic factors resulting in retarded cell migration and invasions. The in-vitro results were reproducible in the reliable in-vivo solid tumour model. Taken together, we conclude that BP-1B impairs angiogenesis by blocking nuclear localization of HIF-1α which can be translated into a potent HIF-1α inhibitor.

BP-1T, an antiangiogenic benzophenone-thiazole pharmacophore, counteracts HIF-1 signalling through p53/MDM2-mediated HIF-1α proteasomal degradation

Hypoxia is a feature of all solid tumours, contributing to tumour progression. Activation of HIF-1α plays a critical role in promoting tumour angiogenesis and metastasis. Since its expression is positively correlated with poor prognosis for cancer patients, HIF-1α is one of the most convincing anticancer targets. BP-1T is a novel antiproliferative agent with promising antiangiogenic effects. In the present study, the molecular mechanism underlying cytotoxic/antiangiogenic effects of BP-1T on tumour/non-tumour angiogenesis was evaluated. Evidences show that BP-1T exhibits potent cytotoxicity with prolonged activity and effectively regressed neovessel formation both in reliable non-tumour and tumour angiogenic models. The expression of CoCl₂-induced HIF-1α was inhibited by BP-1T in various p53 (WT)-expressing cancer cells, including A549, MCF-7 and DLA, but not in mutant p53-expressing SCC-9 cells. Mechanistically, BP-1T mediates the HIF-1α proteasomal degradation by activating p53/MDM2 pathway and thereby downregulated HIF-1α-dependent angiogenic genes such as VEGF-A, Flt-1, MMP-2 and MMP-9 under hypoxic condition of in vitro and in vivo solid tumour, eventually leading to abolition of migration and invasion. Based on these observations, we conclude that BP-1T acts on HIF-1α degradation through p53/MDM2 proteasome pathway.

The Changes of HIF-1α and VEGF Expression After TACE in Patients With Hepatocellular Carcinoma

As a common malignant tumor, hepatocellular carcinoma (HCC) has a high prevalence and is a serious threat to human health. The surgical resection rate of HCC is low, and the prognosis is poor. Although transarterial chemoembolization (TACE) is the main treatment for HCC patients who are not candidates for surgical resection, it is not considered a curative procedure. For HCC, poor TACE efficacy or TACE failure may be related to tumor angiogenesis of the residual disease. Among the many regulatory factors in tumor angiogenesis, hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) play vital roles in this process. In this paper, we conducted a review of the dynamic change and relevance of HIF-1α and VEGF levels after TACE of HCC patients.

Spontaneous γH2AX Foci in Human Solid Tumor-Derived Cell Lines in Relation to p21WAF1 and WIP1 Expression

Phosphorylation of H2AX on Ser139 (γH2AX) after exposure to ionizing radiation produces nuclear foci that are detectable by immunofluorescence microscopy. These so-called γH2AX foci have been adopted as quantitative markers for DNA double-strand breaks. High numbers of spontaneous γH2AX foci have also been reported for some human solid tumor-derived cell lines, but the molecular mechanism(s) for this response remains elusive. Here we show that cancer cells (e.g., HCT116; MCF7) that constitutively express detectable levels of p21^WAF1 (p21) exhibit low numbers of γH2AX foci (<3/nucleus), whereas p21 knockout cells (HCT116p21−/−) and constitutively low p21-expressing cells (e.g., MDA-MB-231) exhibit high numbers of foci (e.g., >50/nucleus), and that these foci are not associated with apoptosis. The majority (>95%) of cells within HCT116p21−/− and MDA-MB-231 cultures contain high levels of phosphorylated p53, which is localized in the nucleus. We further show an inverse relationship between γH2AX foci and nuclear accumulation of WIP1, an oncogenic phosphatase. Our studies suggest that: (i) p21 deficiency might provide a selective pressure for the emergence of apoptosis-resistant progeny exhibiting genomic instability, manifested as spontaneous γH2AX foci coupled with phosphorylation and nuclear accumulation of p53; and (ii) p21 might contribute to positive regulation of WIP1, resulting in dephosphorylation of γH2AX.

Conventional transarterial chemoembolization vs microsphere embolization in hepatocellular carcinoma: A meta-analysis

AIM: To compare conventional transarterial chemoembolization (c-TACE) with microsphere embolization in hepatocellular carcinoma (HCC).

METHODS: We searched PubMed, Medline, Embase and the Cochrane Library for trials assessing the efficacy and safety of c-TACE in comparison with those of yttrium-90 microsphere or drug-eluting bead embolization from January 2004 to December 2013. Overall survival rate (OSR), tumor response [complete response, partial response (PR), stable disease (SD), progressive disease (PD)], α-fetoprotein (AFP) response, progression rate and complications were compared and analyzed. Pooled ORs with 95%CI were calculated using either the fixed-effects model or random-effects model. All statistical analyses were conducted using the Review Manager (version 5.1.) from the Cochrane collaboration.

RESULTS: Thirteen trials were identified, including a total of 1834 patients; 1233 were treated with c-TACE, 377 underwent yttrium-90 microsphere embolization and 224 underwent drug-eluting bead embolization. The meta-analysis with either the random-effects model or fixed-effects model indicated that microsphere embolization was associated with significantly higher OSRs compared with those of c-TACE (OR_1-year = 1.38, 95%CI_1-year: 1.05-1.82; OR_2-year = 2.88, 95%CI_2-year: 1.18-7.05; OR_3-year = 2.15, 95%CI_3-year: 1.18-3.91). The complete tumor response rates of patients who underwent microspheres embolization were significantly higher than those of patients treated with c-TACE (OR = 2.19, 95%CI: 1.31-3.64). The tumor progression rate after microsphere embolization was markedly lower than that after c-TACE (OR = 0.56, 95%CI: 0.39-0.81). There was no significant difference between microsphere embolization and c-TACE in PR (OR = 0.73, 95%CI: 0.47-1.15), SD (OR = 1.07, 95%CI: 0.79-1.44), PD (OR = 0.75, 95%CI: 0.33-1.68), AFP response (OR = 1.38, 95%CI: 0.64-2.94) and complications (OR = 0.68, 95%CI: 0.46-1.00).

CONCLUSION: Our analysis indicated that microsphere embolization was associated with superior survival and treatment response in comparison with c-TACE in the treatment of patients with HCC.

The suppressive effect of resveratrol on HIF-1α and VEGF expression after warm ischemia and reperfusion in rat liver

Background

Hypoxia-inducible factor-1α (HIF-1α) is overexpressed in many human tumors and their metastases, and is closely associated with a more aggressive tumor phenotype. The aim of the present study was to investigate the effect of resveratrol (RES) on the expression of ischemic-induced HIF-1α and vascular endothelial growth factor (VEGF) in rat liver.

Methods

Twenty-four rats were randomized into Sham, ischemia/reperfusion (I/R), and RES preconditioning groups. I/R was induced by portal pedicle clamping for 60 minutes followed by reperfusion for 60 minutes. The rats in RES group underwent the same surgical procedure as I/R group, and received 20 mg/kg resveratrol intravenously 30 min prior to ischemia. Blood and liver tissue samples were collected and subjected to biochemical assays, RT-PCR, and Western blot assays.

Results

I/R resulted in a significant (P<0.05) increase in liver HIF-1α and VEGF at both mRNA and protein levels 60 minutes after reperfusion. The mRNA and protein expressions of HIF-1α and VEGF decreased significantly in RES group when compared to I/R group (P<0.05).

Conclusion

The inhibiting effect of RES on the expressions of HIF-1α and VEGF induced by I/R in rat liver suggested that HIF-1α/VEGF could be a promising drug target for RES in the development of an effective anticancer therapy for the prevention of hepatic tumor growth and metastasis.

The role of hypoxia inducible factor-1 in hepatocellular carcinoma

Hypoxia is a common feature of many solid tumors, including hepatocellular carcinoma (HCC). Hypoxia can promote tumor progression and induce radiation and chemotherapy resistance. As one of the major mediators of hypoxic response, hypoxia inducible factor-1 (HIF-1) has been shown to activate hypoxia-responsive genes, which are involved in multiple aspects of tumorigenesis and cancer progression, including proliferation, metabolism, angiogenesis, invasion, metastasis and therapy resistance. It has been demonstrated that a high level of HIF-1 in the HCC microenvironment leads to enhanced proliferation and survival of HCC cells. Accordingly, overexpression, of HIF-1 is associated with poor prognosis in HCC. In this review, we described the mechanism by which HIF-1 is regulated and how HIF-1 mediates the biological effects of hypoxia in tissues. We also summarized the latest findings concerning the role of HIF-1 in the development of HCC, which could shed light on new therapeutic approaches for the treatment of HCC.

HIF-1α genetic variants and protein expression confer the susceptibility and prognosis of gliomas

To investigate the role of HIF-1α genetic polymorphism of c.1772C>T and c.1790G>A in the incidence and prognosis of gliomas in a Chinese cohort, a total of 387 gliomas patients and 437 age- and sex-matched healthy controls were recruited. The genetic polymorphism of c.1772C>T and c.1790G>A was determined. We found that the genotype distribution at c.1772C>T showed significant difference between patients and controls. Multivariable analyses showed a significantly higher risk for gliomas in 1772TT genotype carriers (odds ratio 2.68, with CC as reference). In addition, we also found a significantly higher risk for grade III + IV gliomas was observed in 1772TT genotype carriers (odds ratio 2.21, with CC as reference). The overall survival rates in patients with 1772TT or 1772CT genotype were markedly lower compared with patients with CC (both P < 0.01). Our in vitro studies revealed that HIF-1α regulates the proliferation, migration and invasion of human glioma U251 cells. This study suggests that the c.1772C>T polymorphisms may be used as a molecular marker for gliomas occurrence, grades and clinical outcome in gliomas patients.

Meta-analysis of immunohistochemical expression of hypoxia inducible factor-1α as a prognostic role in gastric cancer

AIM: To conduct a meta-analysis to evaluate the prognostic role of hypoxia inducible factor-1α (HIF-1α) expression in gastric cancer.

METHODS: The PubMed, EMBASE, and Web of Science databases were searched systematically for all articles published in English before August, 2013. Pooled effect was calculated from the available data to evaluate the association between HIF-1α expression and 5-year overall survival and tumor clinicopathological features in gastric cancer patients. Pooled odds ratios (ORs) with 95%CIs were calculated using either a fixed-effects or a random-effects model.

RESULTS: Nine studies matched the selection criteria, which reported on 1103 subjects, 548 of whom had HIF-1α positive expression (50%). This meta-analysis indicated that HIF-1α positive expression in gastric cancer correlated with lower 5-year overall survival (OR = 0.36; 95%CI: 0.21-0.64), worse tumor differentiation (OR = 0.38; 95%CI: 0.23-0.64), deeper invasion (OR = 0.42; 95%CI: 0.32-0.57), higher rates of lymph node metastasis (OR = 2.23; 95%CI: 1.46-3.40), lymphatic invasion (OR = 2.50; 95%CI: 1.46-4.28), and vascular invasion (OR = 1.80; 95%CI: 1.29-2.51), and higher TNM stage (III + IV) (OR = 0.31; 95%CI: 0.15-0.60).

CONCLUSION: HIF-1α positive expression indicates a poor prognosis for patients with gastric cancer. Further studies are required to confirm these results.

Roles of HIF-1 in hepatocellular carcinoma

Hypoxia inducible factor-1 (HIF-1) is a key regulator of the cellular response to hypoxia. Since cell growth is out of control in hepatocellular carcinoma (HCC), HIF-1 activity is significantly enhanced in HCC to help cells adapt to the hypoxic microenvironment. HIF-1 plays a critical role in the occurrence and development of HCC through activating the target genes that participate in the regulation of cell proliferation and apoptosis, energy metabolism, angiogenesis, invasion and metastasis, resistance to chemotherapy and radiotherapy. Given the specific expression and regulation of HIF-1 in HCC growth, HIF-1 may become a new target for drug therapy and gene therapy, which provides a new avenue for neoadjuvant therapy of HCC in the future.