An up-to-date anti-cancer treatment strategy focusing on HIF-1alpha suppression: its application for refractory ovarian cancer

MARK2/4 promotes Warburg effect and cell growth in non-small cell lung carcinoma through the AMPKα1/mTOR/HIF-1α signaling pathway

MARKs kinase belongs to an AMPK-related family kinase plays a critical role in tumor progression, but its exact role and contribution of four different isoforms remain largely ambiguous. In this study, we used a clinical dataset compiled by The Cancer Genome Atlas (TCGA) and GEO revealed that MARK2 and MARK4 expressions were significantly upregulated in non-small cell lung cancer (NSCLC) compared with normal tissues. Furthermore, expressions of MARK2/4 were highly appeared in advanced stages and associated with the low survival rate of NSCLC patients. Functional assays demonstrated that MARK2/4 deletion or MARKs inhibition significantly suppressed aerobic glycolysis and cell growth in NSCLC cells. Mechanistically, MARK2/4 stimulates the mTOR/HIF-1α pathway and subsequently alleviates AMPK activity via physically associate with Raptor and AMPKα1, thereby facilitating aerobic glycolysis and cell growth in NSCLC cells. However, these effects were markedly reversed by MARKs inhibitor 39621, or MARK2/4 deletion, mTOR inhibitor rapamycin, or AMPK activator AICAR. Together, the data demonstrated that MARK2/4 exerts its oncogenic effects by facilitating metabolic reprogramming in NSCLC cells. Therefore, MARK2/4 might be a potential therapeutic target for lung cancer.

CD226 deficiency promotes glutaminolysis and alleviates mitochondria damage in vascular endothelial cells under hemorrhagic shock

Hemorrhagic shock (HS) is common in clinical emergencies, leading to millions of deaths each year globally. CD226 is a costimulatory adhesion molecule expressed on both immune cells and endothelial cells (ECs) to regulate their metabolic activity and function. As endothelial dysfunction occurs after HS, the roles CD226 plays in vascular EC metabolism were investigated. CD226^fl/fl Tek^cre mice were adopted to achieve vascular EC-specific knockout of CD226, and subjected to HS modelling. Serum levels of crucial intermediate metabolites were evaluated through liquid chromatography-mass spectrometry analysis. Human umbilical vein ECs (HUVECs) were used to study the effects of CD226 under hypoxia in vitro. Seahorse analysis evaluated the cellular glycolysis and mitochondria bioenergetics. Results showed that CD226 deficiency in vascular ECs alleviated HS-induced intestinal damage and inflammatory response in mice. Animal studies indicated an improved energy metabolism when CD226 was knocked out in ECs after HS, as evidenced by enhanced glutamine-glutamate metabolism and decreased lactic acid levels. Glut-1 was upregulated in mouse vascular ECs after HS and HUVECs under hypoxia, combined with decreased CD226. Moreover, HUVECs with CD226 knockdown exhibited relieved mitochondrial damage and early apoptosis under hypoxia, whereas CD226 overexpression showed opposite effects. Seahorse analysis showed that downregulated CD226 significantly increased mitochondrial ATP production and glucose uptake in HUVECs under hypoxia. Additionally, Erk/PHD2 signaling-mediated HIF-1α/Glut-1 and HIF-2α/ASCT2 pathways were involved in CD226 regulation on HUVEC glutaminolysis after hypoxia. Hence, CD226 deficiency promotes bypass energy supply to vascular ECs under ischemic or hypoxic stress, to ameliorate the stress-mediated metabolic disturbance.

Ultrasound‑targeted microbubble destruction‑mediated overexpression of Sirtuin 3 inhibits the progression of ovarian cancer

Ultrasound-targeted microbubble destruction (UTMD) has recently been developed as a promising noninvasive tool for organ- and tissue-specific gene or drug delivery. The aim of the present study was to explore the role of UTMD-mediated Sirtuin 3 (SIRT3) overexpression in the malignant behaviors of human ovarian cancer (HOC) cells. Reverse transcription-quantitative PCR was performed to detect SIRT3 mRNA expression levels in normal human ovarian epithelial cells and HOC cell lines; low SIRT3 expression was found in HOC cell lines, and the SKOV3 cell line was used in the following experiments. The SIRT3-microbubble (MB) was prepared, and the effects of ultrasound-treated SIRT3-MB on biological processes of SKOV3 cells were determined. The proliferation, migration, invasion and apoptosis of SKOV3 cells were measured after SIRT3 upregulation by UTMD. Xenograft tumors in nude mice were induced to observe tumor growth in vivo. Upregulation of SIRT3 inhibited the malignant behaviors of SKOV3 cells, whereas UTMD-mediated SIRT3 upregulation further inhibited proliferation, epithelial-mesenchymal transition, invasion and migration, and induced apoptosis of SKOV3 cells, and it also inhibited tumor formation and growth in vivo. Moreover, the present study identified hypoxia inducible factor-1α (HIF-1α) as a target of SIRT3. The present study provided evidence that UTMD-mediated overexpression of SIRT3 may suppress HOC progression through the inhibition of HIF-1α.

Association of HIF1-α gene polymorphisms with advanced non-small cell lung cancer prognosis in patients receiving radiation therapy

We investigated the association between single nucleotide polymorphisms (SNPs) in the HIF1A gene and the prognosis of advanced non-small cell lung cancer (NSCLC) patients undergoing radiation therapy. Patient overall survival (OS) and progression-free survival (PFS) were analyzed. The rs11549465 TT genotype was associated with poor PFS (P<0.001) and OS (P=0.001). The rs2057482 TT genotype was also associated with poor PFS (P=0.002) and OS (P=0.007). Stratified analyses revealed that these associations occurred in patients with a smoking history, squamous cell carcinoma, and stage IIIA disease, as well as those receiving radiation therapy a radiation dose of ≥70 Gy. We found associations between SNPs and PFS but not OS in patients without a smoking history, other histological types, and stage IIIB disease, as well as those undergoing chemoradiotherapy with a radiation dose of <70 Gy. No associations were observed between rs11549467 or rs110873142 and NSCLC prognosis. These results suggest that HIF1A polymorphisms can be used as independent prognostic biomarkers for NSCLC patients receiving radiation therapy.

Expression of hypoxia-inducible factor-1α affects tumor proliferation and antiapoptosis in surgically resected lung cancer

Hypoxia-inducible factor (HIF)-1 is a transcription factor that allows cells to adapt to hypoxic situations. HIF-1 is known to control tissue proliferation, antiapoptosis, angiogenesis and glucose metabolism. Furthermore, HIF-1 is involved in the growth of numerous cancer types. The present study aimed to examine the expression of HIF-1α immunohistochemically in resected lung cancers. The present study included 216 consecutive patients with lung cancer who underwent resection between April 2013 and January 2015. The patients' clinicopathological data were summarized, including imaging findings, tumor pathological characteristics, and the patient's age, sex and smoking status. The intratumoral expression of HIF-1α, survivin, c-Myc and the Ki-67 proliferation index were evaluated immunohistochemically. The patients were divided into two groups, according to the expression of HIF-1α (low vs. high) and the clinicopathological characteristics of these groups were compared. It was revealed that HIF-1α expression was significantly associated with ground glass opacity ratio, maximum standardized uptake value index, histological type (squamous cell carcinoma), differentiation and lymphatic invasion. Regarding the immunohistochemical findings, HIF-1α expression was significantly correlated with the expression levels of c-Myc (P<0.01) and survivin (P<0.01). Furthermore, the Ki-67 proliferation index was significantly higher in high-HIF-1α tumors compared with in low-HIF-1α tumors (P=0.01). The multivariate analysis identified squamous cell carcinoma, high SUVmax and lymphatic invasion as significant and independent factors for high HIF-1α expression. In conclusion, HIF-1 was highly expressed in certain subgroups of lung cancer with specific histopathology and images. HIF-1α expression was associated with tumor proliferation and antiapoptosis in lung cancer.

Effect of HIF1α on Foxp3 expression in CD4+ CD25- T lymphocytes

The aim of the present study was to investigate the effect of HIF1α on Foxp3 expression in CD4(+) CD25(-) T lymphocytes. CD4(+) CD25(-) T lymphocytes were sorted from PBMC using a CD4(+) CD25(+) regulatory T cell isolation kit. Lentivirus containing lentiviral vector that overexpressed HIF1α (HIF-lenti) and those containing empty expression vector (control-lenti) were produced. Meanwhile, lentivirus that contained lentiviral vector that suppressed HIF1α expression (siHIF-lenti) and those containing control vector (sicontrol-lenti) were also generated. The sorted CD4(+) CD25(-) T lymphocytes were infected with HIF-lenti, control-lenti, siHIF-lenti, and sicontrol-lenti, respectively. Approximately 72 hr after transduction, real-time PCR and Western blot were carried out to analyze the RNA and protein expression level of HIF1α and Foxp3. CD4(+) CD25(-) T lymphocytes cultured under 21% O2 , 5% CO2 (normoxia) and 1% O2 , 5% CO2 (hypoxia) were used as control. Our results showed that overexpression of HIF1α increased both mRNA and protein expression of Foxp3 and, meanwhile, suppression of HIF1α expression by RNAi could reverse high Foxp3 expression in CD4(+) CD25(-) T lymphocytes caused by hypoxic culture. These results suggested that hypoxia could stimulate Foxp3 expression by increasing HIF1α expression in CD4(+) T lymphocytes which may promote CD4(+) T lymphocytes to convert to Treg.

Apoptosis Induction by the Total Flavonoids from Arachniodes exilis in HepG2 Cells through Reactive Oxygen Species-Mediated Mitochondrial Dysfunction Involving MAPK Activation

Arachniodes exilis is used as a folk medicine in China and proved to have antibacterial, anti-inflammatory, and sedative activities. In the present study, the antitumor effect of the total flavonoids of A. exilis (TFAE) against HepG2 cells was evaluated. The results showed that TFAE inhibited the growth of HepG2 cells in a dosage- and time-dependent manner. Flow cytometry and Hoechst 33342 fluorescence staining results showed that TFAE could significantly increase the apoptosis ratio of HepG2 cells, which is accompanied with increased intracellular reactive oxygen species (ROS) production and decreased mitochondrial membrane potential (ΔΨm). Western blotting indicated that TFAE downregulated the ratio of Bcl-2/Bax, increased cytochrome c release, and activated the caspases-3 and -9. Further analysis showed that TFAE stimulated the mitogen-activated protein kinase (MAPK). However, treatment with NAC (reactive oxygen species scavenger) and MAPK-specific inhibitors (SP600125 and SB203580) could reverse the changes of these apoptotic-related proteins. These results suggested that TFAE possessed potential anticancer activity in HepG2 cells through ROS-mediated mitochondrial dysfunction involving MAPK pathway.

Analysis of mTOR inhibition-involved pathway in ovarian clear cell adenocarcinoma

This study was designed to clarify the mechanism of the mammalian target of rapamycin (mTOR)-hypoxia inducible factor-1 (HIF-1) pathway using the cultured cell strain derived from human ovarian clear cell adenocarcinoma (CCA). Everolimus (a derivative of rapamycin)-treated cells and non-treated cells did not show any difference in mTOR expression. But, phosphorylated-mTOR (p-mTOR) expression significantly decreased in the treated cells, and mTOR-related factors such as phosphorylated-4E-BP1 (p-4E-BP1), HIF-1α, and vascular endothelial growth factor (VEGF) in the downstream region of mTOR revealed a marked decrease in expression. The analysis of influences of the drug on the HIF-1α degradation system showed an increase in von-Hippel Lindau (VHL) expression in the treated cells. Increase of cleaved caspase-3, one of key factors involved in apoptosis, was also shown in the treated cells. In the next step, using nude mice implanted with RMG-1 cells, a decrease in tumor size was demonstrated in 4 of the 7 mice which were orally administered with everolimus. As a result, it was suggested that everolimus administration would be helpful as an anti-tumor therapy for CCA not only via down-regulation of p-mTOR but also degradation of HIF-1α by VHL and induction of apoptosis by cleaved caspase-3.

Molecular typing of epithelial ovarian carcinomas using inflammatory markers

BACKGROUND

Ovarian epithelial carcinomas have recently been classified as slow growing type I tumors and rapidly growing highly aggressive type II tumors. The present study sought to molecularly characterize type I and II tumors using known molecular markers.

METHODS

Specimens from 213 patients with ovarian carcinoma were categorized as type I or type II, and evaluated by immunohistochemistry for the inflammatory markers glucose transporter protein-1 (Glut-1), inducible nitric oxide synthase (iNOS), cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and nuclear factor kappa B. Statistical analysis was performed to investigate whether these molecular markers could distinguish between type I and type II tumors. Kaplan-Meier survival curves and COX regression analysis were used to determine the prognostic effect of these markers on survival in the 2 types of tumors.

RESULTS

Overexpression of COX-1, COX-2, iNOS, and Glut-1 was significantly higher in type II tumors (P < .05). Women with type II tumors had a poorer median survival (60 months) as compared with those with type I tumors (141 months) (P = .0001). Multivariate analysis revealed type II tumors, late stage, and age >60 years as significant predictors of poor survival. For type II tumors, median survival of patients with tumors overexpressing COX-2 was 44 compared with 85 months for those with tumors with low COX-2 expression (P = .029). Looking at both type I and II tumors, the number of markers simultaneously overexpressed in each tumor was a significant predictor of poor patient survival (P = .005).

CONCLUSIONS

The present study demonstrates that the new proposed histologic classification of ovarian epithelial carcinomas correlates with a distinct expression of inflammatory pathway proteins. High expression of these markers may explain the different biologic behavior of these 2 tumor types and provide targets for therapy.

Granulosa cell tumor with activated mTOR-HIF-1alpha-VEGF pathway

The DNA-binding activity of hypoxia-inducible factor-1 alpha (HIF-1alpha) has been analyzed for various gynecological tumors. Among the tumors that were studied, there was a finding of a high level of DNA-binding HIF-1alpha activity, although it was limited to one case of adult type granulosa cell tumor (GCT). In this case a 60-year-old female had marked immunohistochemical expression of HIF-1alpha. The expressions of the mammalian target of rapamycin (mTOR) and phosphorylated-mTOR (p-mTOR) were also marked, and vascular endothelial growth factor (VEGF) was moderately expressed. To compare the expression profiles, 11 consecutive cases with adult type GCT were used. All cases showed marked expressions of HIF-1alpha and mTOR, but p-mTOR expression was moderately to markedly observed in four of the 12 cases. VEGF was expressed in all cases in varying degrees. Based on the evidence that downregulation of the mTOR pathway due to treatment with rapamycin (everolimus) would suppress tumor cell growth, an experimental study using the GCT cell line was designed to clarify whether HIF-1alpha and VEGF expressions decline. As a result, the expressions of p-mTOR, HIF-1alpha and VEGF were suppressed, but those of mTOR were not. It was concluded that mTOR-targeted therapy may represent a promising strategy for some GCT with an activated mTOR-HIF-1alpha-VEGF pathway.

Association of hypoxia-inducible factor-1 expression with histology in epithelial ovarian tumors: a quantitative analysis of HIF-1

BACKGROUND

Hypoxia-inducible factor-1 (HIF-1) is an essential transcription factor that mediates cellular and systemic homeostatic responses to reduced oxygen availability in mammals. So far, using immunohistochemistry we have analyzed the association of HIF-1alpha expression with histological type among epithelial ovarian tumors. In the present study, quantitative analyses of activated HIF-1 level in the nucleus and of accumulated HIF-1alpha level in the cytoplasm were performed to clarify whether or not the hypoxic state would be correlated to histology, malignancy, and tumor size in epithelial ovarian tumors.

METHOD

HIF-1 level in the nucleus was analyzed using DNA binding assay, and HIF-1alpha level in the cytoplasm was measured by ELISA for a total of 36 epithelial ovarian tumors as follows: 5 serous adenocarcinomas (SEAs), 7 clear cell adenocarcinomas (CLAs), 7 endometrioid adenocarcinomas (ENAs), 4 mucinous adenocarcinomas (MUAs), 2 mucinous borderline tumors (MBTs), and 11 mucinous adenomas.

RESULTS

HIF-1 level (mg/ml) in the nucleus and HIF-1alpha level (mg/ml) in the cytoplasm were on average 0.116 and 0.178 for SEAs, 0.328 and 0.306 for CLAs, 0.171 and 0.305 for ENAs, 0.097 and 0.176 for MUAs, 0.224 and 0.180 for mucinous borderline tumors, 0.152 and 0.154 for mucinous adenomas. CLAs showed the highest levels for both of HIF-1 and HIF-1alpha, while MUAs showed the lowest levels of both. Mucinous adenomas were higher in HIF-1 than MUAs.

CONCLUSION

Hypoxic state was considered to be closely related to histological type of epithelial ovarian tumors, suggesting that CLAs may be most hypoxic. In the comparison of mucinous tumors, malignancies would not always become most hypoxic. Tumor size may not be strongly associated with hypoxic state.

Molecular composition, activation mechanism of hypoxia-inducible factor-1 and targeted therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumor in the world, with a complex process involving multi-center, multi-cause and multi-genes. Surgical resection is still the main treatment. However, the diagnosis of HCC mostly occurs at middle or advanced stage, and the prognosis is very poor. Therefore, the development of a novel molecular marker for early diagnosis and a new target for gene therapy become hot spots. Hypoxia-inducible factor-1 (HIF-1) takes part in the development, metastasis and recurrence of HCC, and it has potential applications in the early diagnosis and molecular targeted therapy of HCC. We presented a review on molecular composition, activation mechanism of HIF-1, and the targeted therapeutic approaches applied to hepatocellular carcinoma.