The Potential Role of Hypoxia Inducible Factor 1α in Tumor Progression after Hypoxia and Chemotherapy in Hepatocellular Carcinoma

The disruption and hyperpermeability of blood-labyrinth barrier mediates cisplatin-induced ototoxicity

The ototoxic mechanisms of cisplatin on the organ of Corti and spiral ganglion neurons have been extensively studied, while few studies have been focused on the stria vascularis (SV). Herein, we verified the functional and morphological impairment in SV induced by a single injection of cisplatin (12 mg/kg, I.P.), represented by a reduction in Endocochlear Potentials (EP) and strial atrophy, and explored underlying mechanisms. Our results revealed increased extravasation of chromatic tracers (Evans blue dye and FITC-dextran) around microvessels after cisplatin exposure. The increased vascular permeability could be attributed to changes of pericytes (PCs) and perivascular-resident macrophage-like melanocytes (PVM/Ms) in number or morphology, as well as the enhanced level of HIF-1α and downstream VEGF. This capillary leakage led to a high accumulation of cisplatin in the perivascular space in SV, and disrupted the integrity of blood-labyrinth barrier (BLB). Also, tight junction (ZO-1) loosening and Na⁺, K⁺-ATPase damage was considered to be other critical contributors of BLB breakdown, which resulted in EP drop and consequent hearing loss. This study explored the role of stria vascularis in cisplatin-induced ototoxicity in terms of BLB hyperpermeability and pointed to a novel therapeutic target for the prevention of cisplatin-related hearing loss.

Targeting Hypoxia: Revival of Old Remedies

Tumour hypoxia is significantly correlated with patient survival and treatment outcomes. At the molecular level, hypoxia is a major driving factor for tumour progression and aggressiveness. Despite the accumulative scientific and clinical efforts to target hypoxia, there is still a need to find specific treatments for tumour hypoxia. In this review, we discuss a variety of approaches to alter the low oxygen tumour microenvironment or hypoxia pathways including carbogen breathing, hyperthermia, hypoxia-activated prodrugs, tumour metabolism and hypoxia-inducible factor (HIF) inhibitors. The recent advances in technology and biological understanding reveal the importance of revisiting old therapeutic regimens and repurposing their uses clinically.

Hepatic Artery Infusion Chemotherapy Using Fluorouracil, Leucovorin, and Oxaliplatin versus Transarterial Chemoembolization as Initial Treatment for Locally Advanced Hepatocellular Carcinoma: A Propensity Score-Matching Analysis

PURPOSE

To compare the efficacy and safety of hepatic arterial infusion chemotherapy (HAIC) with a modified fluorouracil, leucovorin, and oxaliplatin (mFOLFOX) regimen with that of transarterial chemoembolization as a locoregional treatment for patients with locally advanced hepatocellular carcinoma (HCC).

METHODS

This retrospective study included adult patients with locally advanced HCC who received first-line treatment with either HAIC-mFOLFOX or conventional transarterial chemoembolization monotherapy from January 2015 to December 2016. The outcomes, including tumor response rates, evaluated via imaging assessment using the modified response evaluation criteria in solid tumors; overall survival; progression-free survival; and safety, were compared. The propensity score-matching methodology was used to reduce the influence of confounding factors on the outcomes.

RESULTS

The study included 131 patients with locally advanced HCC who underwent transarterial chemoembolization and 101 who received HAIC-mFOLFOX as initial treatment. After propensity score matching (n = 67 in each group), patients who received HAIC-mFOLFOX had a higher objective response rate (43.3% vs 13.4%, P = .001), longer median overall survival (13.9 vs 6.0 months, P < .001), and longer median progression-free survival (6.4 vs 2.8 months, P = .001) than those who underwent transarterial chemoembolization. The survival benefit with HAIC-mFOLFOX was strengthened in patients with HCC with vascular invasion (hazard ratio: 0.379; 95% confidence interval: 0.237-0.607). HAIC-mFOLFOX was associated with lower incidences of severe adverse events (8.9% vs 22.9%) and liver toxicity than transarterial chemoembolization.

CONCLUSIONS

Compared with transarterial chemoembolization, HAIC-mFOLFOX is a potentially safer and more effective locoregional therapy for patients with locally advanced HCC.

Therapeutic modulators of hepatic stellate cells for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary tumor in the liver and is a leading cause of cancer-related death worldwide. Activated hepatic stellate cells (HSCs) are key components of the HCC microenvironment and play an important role in the onset and progression of HCC through the secretion of growth factors and cytokines. Current treatment modalities that include chemotherapy, radiotherapy and ablation are able to activate HSCs and remodel the tumor microenvironment. Growing evidence has demonstrated that the complex interaction between activated HSCs and tumor cells can facilitate cancer chemoresistance and metastasis. Therefore, therapeutic targeting of activated HSCs has emerged as a promising strategy to improve treatment outcomes for HCC. This review summarizes the molecular mechanisms of HSC activation triggered by treatment modalities, the function of activated HSCs in HCC, as well as the crosstalk between tumor cells and activated HSCs. Pathways of activated HSC reduction are discussed, including inhibition, apoptosis, and reversion to the inactivated state. Finally, we outline the progress and challenges of therapeutic approaches targeting activated HSCs in the development of HCC treatment.

Hypoxia-induced miR-191-C/EBPβ signaling regulates cell proliferation and apoptosis of fibroblast-like synoviocytes from patients with rheumatoid arthritis

BACKGROUND

Hypoxia plays an important role in the proliferation of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), leading to pathology of RA. This study was conducted to evaluate hypoxia-induced microRNAs (hypoxamiR) in RA-FLS and its role in the function of RA-FLS.

METHODS

RA-FLS were cultured under normoxia (21% O₂) or hypoxia (3% O₂) condition, followed by a microRNA (miRNA) array analysis. The upregulation of miR-191 by hypoxia was confirmed in RA-FLS and FLS from osteoarthritis (OA) patients by quantitative real-time polymerase chain reaction (RT-PCR). Transfection of miR-191 mimic and inhibitor was used to investigate the function of miR-191 in RA-FLS. The functional targets of miR-191 were predicted by bioinfomatics and then validated by reporter gene assay.

RESULTS

A subset of miRNAs was identified to be induced by hypoxia including miR-191. The upregulation of miR-191 was found to be specific in hypoxic RA-FLS, compared to hypoxic OA-FLS. We observed that miR-191 in RA-FLS increased cellular proliferation via promoting G₁/S transition of the cell cycle and suppressed cell apoptosis induced by cell starvation. Bioinformatical analysis and experimental assays identified CCAAT/enhancer binding protein β (C/EBPβ) as a target gene of miR-191 in RA-FLS. Enforced expression of C/EBPβ rescued the cellular phenotypes induced by miR-191. In addition, an inverse correlation between the C/EBPβ level and hypoxia stimulation was found in RA-FLS, and overexpression of C/EBPβ could partly rescue the hypoxia-induced cell proliferation.

CONCLUSION

We demonstrated the miR-191-C/EBPβ signaling pathway mediating the hypoxia-induced cell proliferation in RA.

A phase 2 study of the efficacy and biomarker on the combination of transarterial chemoembolization and axitinib in the treatment of inoperable hepatocellular carcinoma

BACKGROUND

A surge of vascular endothelial growth factor (VEGF) after transarterial chemoembolization (TACE) may contribute to tumor progression. Axitinib is a potent antiangiogenic agent with main activity against VEGF receptors 1 to 3. To the authors' knowledge, its role in combination with TACE for the treatment of patients with inoperable hepatocellular carcinoma (HCC) is unclear.

METHODS

A phase 2 clinical trial (ClinicalTrials.gov identifier NCT01352728) was conducted to evaluate the combination treatment. Patients with inoperable HCC who were potential candidates for TACE initiated treatment with axitinib at a dose of 5 mg twice daily and were evaluated for the need for TACE every 8 weeks. Axitinib was withheld 24 hours before TACE, and resumed 24 hours afterward when fulfilling predefined criteria. Radiologic assessment was conducted every 8 weeks. The primary endpoint was the 2-year overall survival (OS) rate.

RESULTS

A total of 50 patients were recruited from March 2011 to April 2014. The mean age of the patients was 61.8 years, and 46 patients (92%) had hepatitis B infection. The Barcelona Clinic Liver Cancer stage B/C percentage was 76% (38 cases)/24% (12 cases). The 2-year OS rate was 43.7%, and the median OS was 18.8 months in the intention-to-treat population. Among the evaluable population (44 patients), 40.9% (18 patients) and 27.3% (12 patients) achieved complete and partial responses, respectively. Common grade 3 or above axitinib-related complications included hand-foot skin reaction (14%) and hypertension (24%). The presence of hypertension during treatment was found to be an independent prognosticator (hazard ratio, 0.563; P = .0073) suggestive of a contributory role of axitinib to efficacy.

CONCLUSIONS

The combination of axitinib and TACE was potentially efficacious for patients with inoperable HCC with a high radiologic response rate. Cancer 2017;123:3977-85. © 2017 American Cancer Society.

Metastasis-Associated Protein 1 Is Involved in Angiogenesis after Transarterial Chemoembolization Treatment

BACKGROUND

Transarterial chemoembolization (TACE), a well-established treatment for unresectable hepatocellular carcinoma (HCC), blocks the arterial blood supply to the tumor, which can be short-lived as development of collateral neovessels, leading to the failure of treatment. Metastasis-associated protein 1 (MTA1) is involved in development of tumors and metastases. However, the role of MTA1 in angiogenesis is still obscure.

METHODS

We detected the expression of MTA1 and hypoxia-inducible factor-1α (HIF-1α) and microvessel density (MVD) value in liver tumor tissues and tumor periphery before and after TACE treatment. Hepatocellular carcinoma cell line HepG2, tube formation assay, and chorioallantoic membrane (CAM) assay were applied to explore the mechanism of MTA1 in angiogenesis.

RESULTS

We found that expression of MTA1 increased after TACE treatment, especially in tumor periphery, which was accompanied by markedly elevated MVD value, indicating a significant correlation between MTA1 and MVD value. Moreover, MTA1 contributed to neovascularization of residual tumors. Cellular experiments further revealed that MTA1 increased the stability and the expression of HIF-1α, and overexpression of MTA1 enhanced tube formation and neovessels of chick embryos.

CONCLUSIONS

MTA1 is an active angiogenic regulator; our results shed light on better understanding in neovascularization, which are helpful to predict prognosis of TACE, and provide evidences for intervention to improve therapeutic effects on HCC.

Ultrasound Triggered Tumor Oxygenation with Oxygen-Shuttle Nanoperfluorocarbon to Overcome Hypoxia-Associated Resistance in Cancer Therapies

Tumor hypoxia is known to be one of critical reasons that limit the efficacy of cancer therapies, particularly photodynamic therapy (PDT) and radiotherapy (RT) in which oxygen is needed in the process of cancer cell destruction. Herein, taking advantages of the great biocompatibility and high oxygen dissolving ability of perfluorocarbon (PFC), we develop an innovative strategy to modulate the tumor hypoxic microenvironment using nano-PFC as an oxygen shuttle for ultrasound triggered tumor-specific delivery of oxygen. In our experiment, nanodroplets of PFC stabilized by albumin are intravenously injected into tumor-bearing mice under hyperoxic breathing. With a low-power clinically adapted ultrasound transducer applied on their tumor, PFC nanodroplets that adsorb oxygen in the lung would rapidly release oxygen in the tumor under ultrasound stimulation, and then circulate back into the lung for reoxygenation. Such repeated cycles would result in dramatically enhanced tumor oxygenation and thus remarkably improved therapeutic outcomes in both PDT and RT treatment of tumors. Importantly, our strategy may be applied for different types of tumor models. Hence, this work presents a simple strategy to promote tumor oxygenation with great efficiency using agents and instruments readily available in the clinic, so as to overcome the hypoxia-associated resistance in cancer treatment.

High nuclear hypoxia-inducible factor 1 alpha expression is a predictor of distant recurrence in patients with resected pancreatic adenocarcinoma

PURPOSE

To evaluate nuclear hypoxia-inducible factor 1α (HIF-1α) expression as a prognostic factor for distant recurrence (DR) and local recurrence (LR) after pancreatic adenocarcinoma resection.

METHODS AND MATERIALS

Tissue specimens were collected from 98 patients with pancreatic adenocarcinoma who underwent resection without neoadjuvant therapy between January 2000 and December 2011. Local recurrence was defined as radiographic or pathologic evidence of progressive disease in the pancreas, pancreatic bed, or associated nodal regions. Distant recurrence was defined as radiographically or pathologically confirmed recurrent disease in other sites. Immunohistochemical staining was performed and scored by an independent pathologist blinded to patient outcomes. High HIF-1α overall expression score was defined as high percentage and intensity staining and thus score >1.33. Univariate analysis was performed for HIF-1α score with LR alone and with DR. Multivariate logistic regression was used to determine predictors of LR and DR.

RESULTS

Median follow-up time for all patients was 16.3 months. Eight patients (8%) demonstrated isolated LR, 26 patients (26.5%) had isolated DR, and 13 patients had both LR and DR. Fifty-three patients (54%) had high HIF-1α expression, and 45 patients (46%) had low HIF-1α expression. High HIF-1α expression was significantly associated with DR (P=.03), and low HIF-1α expression was significantly associated with isolated LR (P=.03). On multivariate logistic regression analysis, high HIF-1α was the only significant predictor of DR (odds ratio 2.46 [95% confidence interval 1.06-5.72]; P=.03). In patients with a known recurrence, an HIF-1α score ≥2.5 demonstrated a specificity of 100% for DR.

CONCLUSIONS

High HIF-1α expression is a significant predictor of distant failure versus isolated local failure in patients undergoing resection of pancreatic adenocarcinoma. Expression of HIF-1α may have utility in determining candidates for adjuvant local radiation therapy and systemic chemotherapy.

The correlation of expression levels of HIF-1α and HIF-2α in hepatocellular carcinoma with capsular invasion, portal vein tumor thrombi and patients' clinical outcome

OBJECTIVES

The roles of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α in the development of hepatocellular carcinoma have not been fully elucidated. Here, we aim to uncover the relationship between the prognosis of hepatocellular carcinoma patients and the expression of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α in tumor tissues.

METHODS

The protein levels of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α were detected by immunohistochemistry on paraffin sections of 126 paired hepatocellular carcinoma tissue and peritumoral tissue samples. The mRNA levels of them were detected by quantitative real-time polymerase chain reaction.

RESULTS

High expression of hypoxia-inducible factor-1α was found in 57.1% (72/126) of tumor specimens, compared with 5.6% (7/126) in peritumoral tissues, while high expression of hypoxia-inducible factor-2α was found in only 13.5% (17/126) of tumors, compared with 47.6% (60/126) of peritumoral tissues. There was high expression of hypoxia-inducible factor-1α protein in hepatocellular carcinoma tissues closely associated with capsular infiltration and portal vein invasion, and thus lower overall survival and disease-free survival of hepatocellular carcinoma patients (P < 0.05). No significant association has been found between the expression of hypoxia-inducible factor-2α protein and capsular infiltration, portal vein invasion, overall survival and disease-free survival (P > 0.05). However, patients with high expression of both hypoxia-inducible factor-1α and hypoxia-inducible factor-2α have a significantly worse outcome than patients with low expression of both hypoxia-inducible factor-1α and hypoxia-inducible factor-2α (P < 0.05).

CONCLUSIONS

The discordant results on expression of hypoxia-inducible factor-1α and hypoxia-inducible factor-2α suggest that these two proteins are differentially regulated in vivo, thus reflecting distinctive protein expression and stabilization mechanisms. The association between hypoxia-inducible factor-1α expression and unfavorable outcome indicates the importance of using hypoxia-inducible factor-1α as a treatment target in hepatocellular carcinoma.

Chloroquine promotes the anticancer effect of TACE in a rabbit VX2 liver tumor model

BACKGROUND

To investigate the efficacy of TACE combined with CQ, an autophagic inhibitor, in a rabbit VX2 liver tumor model.

METHODS

Tumor size was measured. And tumor growth rate was calculated to examine the effect of the combined treatment. Apoptosis was detected by TUNEL assay. Meanwhile, autophagic activity was detected by immunohistochemistry and Western blotting to investigate the mechanism underlying. Liver function was also examined to assess feasibility and safety of the combined therapy.

RESULTS

Tumors in the control grew more than 4 times bigger after 14 days, while that in the group of TACE alone just showed mild growth. But a slight shrinkage was shown after the treatment of CQ+TACE. Growth ratio of TACE alone was 96.45% ± 28.958% while that of CQ+TACE was -28.73% ± 12.265%. Compared with TACE alone, necrosis in CQ+TACE showed no significant difference, however, the apoptosis was much higher. There were only 14.8±3.11% apoptotic cells in TACE, but 33±4.18% in CQ+TACE, which suggests the increased apoptosis in CQ+TACE contributed to the decrease of tumor volume. In terms of autophagic activity, the result is negative when we immunostained sections of the control with LC3 antibody, but positive in TACE alone and CQ+TACE. And the result of Western blot showed that there was just a low level of LC3Ⅱexpressed in the control and CQ alone, but higher in TACE, and much higher in CQ+TACE because CQ inhibited its degradation in autophagy. Compared with control, p62 decreased in TACE, but the decrease was partially reversed in CQ+TACE. In addition, toxicity of CQ+TACE was assessed not higher than TACE alone, which supports the safety of CQ+TACE.

CONCLUSION

CQ+TACE works better than TACE alone in rabbit VX2 liver tumor model because CQ inhibits autophagy induced by TACE. The inhibited autophagy loses its resistance to apoptosis that apoptosis increased, which contributes to the inhibition of tumor growth. This study indicates CQ may be a promising adjuvant to promote the effect of TACE.

Sorafenib suppresses the rapid progress of hepatocellular carcinoma after insufficient radiofrequency ablation therapy: an experiment in vivo

BACKGROUND

Radiofrequency ablation (RFA) is a widely applied treatment for hepatocellular carcinoma (HCC), but insufficient RFA can promote rapid progression of the residual tumor through the hypoxia inducible factor-1α (HIF-1α)/vascular endothelial growth factor A (VEGFA) pathway. Although sorafenib has been successfully applied to advanced HCC, the use of sorafenib in residual tumor cells after RFA has rarely been tested.

PURPOSE

To evaluate the potential role of sorafenib as an adjunct to RFA to reduce the recurrence rate after insufficient RFA.

MATERIAL AND METHODS

Xenograft tumors of SMMC 7721 were created by subcutaneously inoculating nude mice with hepatoma cells (5 × 10(6) cells per mouse). Fourteen days after inoculation, all mice were divided into three groups (control group [sham puncture], RFA group, and RFA combined with sorafenib treatment group) with six mice in each group. Each group was given a different treatment procedure. After treatment, the volume of the tumors was calculated from the resected specimens. The mRNA and protein expression of HIF-1α and VEGFA was quantified by real-time PCR and immunohistochemistry analysis. The micro-vessel density (MVD) was determined by CD34 immunohistochemistry.

RESULTS

Real-time PCR and immunohistochemistry analysis showed that, compared to the RFA group, HIF-1α and VEGFA expression were significantly decreased in the group that received RFA combined with sorafenib treatment (P < 0.05). By comparing the control group with the RFA group, we found that insufficient RFA promoted HIF-1α and VEGFA expression (P < 0.05). Similar results were obtained for MVD expression. Additionally, the combination of RFA with sorafenib therapy resulted in a synergistic reduction in tumor growth compared to insufficient RFA and sham puncture (P < 0.05).

CONCLUSION

Sorafenib was able to inhibit the expression of HIF-1α and VEGFA, and sorafenib was able to increase time to recurrence when used as an adjunct to RFA.

Hepatocellular carcinoma--resection or transplant?

Resection and liver transplantation are considered effective treatments for early-stage hepatocellular carcinoma (HCC). As data from randomized trials are lacking, the choice of technique is controversial. Retrospective analyses suggest that for patients with suboptimal liver function, transplantation is the preferred treatment. For patients with preserved liver function and HCC within the Milan criteria, the overall survival rate is similar for both techniques; therefore resection is the preferred treatment. For tumours beyond the Milan criteria but within acceptable expanded criteria, transplantation has a more favourable outcome than resection. As liver grafts are in short supply, resection followed by transplantation once intrahepatic recurrence is detected would spare patients with favourable or very aggressive tumours from transplantation and enable patients with moderately aggressive tumours to undergo timely transplantation. Currently, resection and transplantation are considered complementary in the management of HCC. Expanding the transplantation and resection criteria of HCC needs to be investigated.

Hepatocellular carcinoma: the place of new medical therapies

Medical therapies have entered center stage in the treatment of hepatocellular carcinoma (HCC) little more than a year after the positive results of a large phase III trial of sorafenib showed a clear survival benefit with sorafenib, a targeted agent, in this setting. Even though this marks a breakthrough in the treatment of HCC, the narrow patient profile necessary for the study to be successful has generated a number of questions regarding the efficacy of this approach in other clinical settings. New studies aiming to define the role of sorafenib from in the adjuvant setting, through patients with more advanced liver disease, all the way to combination treatments of HCC have been initiated. The success of one targeted drug has stimulated enormously the efforts of competitors to develop additional and better drugs, either in a first-line or a second-line setting. These are exciting times for the treatment of HCC, both for physicians and patients. In the years to come we will see an extension of treatment options in different clinical situations in patients with HCC, and survival will be improved in many stages of the disease, except for the most advanced. The rapid increase in knowledge about the molecular mechanisms underlying the development and progression of HCC will lead to a more tailored approach to treatment depending on the molecular characteristics of the tumor and the disease stage.

Role of hypoxia-inducible transcription factor 1alpha for progression and chemosensitivity of murine hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascularized tumor entity with association of arterial vessel density with poor prognosis. The hypoxia-inducible transcription factor HIF-1alpha represents a pivotal regulator of angiogenesis and is thought to determine the angiogenic nature of HCC. However, the precise role of HIF-1alpha during the pathogenesis of HCC remains elusive. We established a functional inactivation of HIF-1alpha in vitro and in vivo via RNAi and Cre/loxP-mediated recombination, respectively, to determine HIF-1alpha's role for tumor growth and chemosensitivity in transgenic and orthotopic murine HCC models. HIF-1alpha-deficient HCC cells displayed significantly reduced anchorage-independent growth and enhanced sensitivity toward etoposide, while basic cellular proliferation was unaffected. Analysis of gross tumor growth failed to detect reduced growth of HIF-1alpha-deficient tumors in the orthotopic and the transgenic HCC model, respectively. In line with the in vitro data, treatment of HIF-1alpha-deficient tumors with etoposide resulted in greater antiproliferative efficacy when compared to wild-type mice. Taken together, our study does not support a pivotal role of HIF-1alpha for tumor growth and angiogenesis in two murine HCC models. However, our data point toward a significant function of HIF-1alpha in determining chemosensitivity of HCC and therefore warrant validation of HIF-1alpha-inhibitors as adjuvant therapeutic agents in clinical studies of human HCC.

Influence of hepatic artery occlusion on tumor growth and metastatic potential in a human orthotopic hepatoma nude mouse model: relevance of epithelial-mesenchymal transition

Hepatic artery ligation (HAL), transarterial embolization (TAE), and transarterial chemoembolization (TACE) have been treatment choices for unresectable hepatocellular carcinoma (HCC). Obstruction of tumor blood supply is one of the most important mechanisms of these therapeutics measures. Here we introduced HAL into a metastatic human HCC orthotopic nude mouse model (using MHCC97L and HepG2 cell lines) to examine the effects of hepatic blood flow obstruction on the metastatic potential of hepatic tumor cells, and to investigate the mechanisms underlying these effects. Our results indicated that HAL inhibited tumor growth but concomitantly elicited tumor adaptation and progression, with increased potential for invasion and distant metastases. The underlying proinvasive mechanism of HAL appeared to be associated with enhanced intratumoral hypoxia and epithelial-mesenchymal transition (EMT) due to hypoxia. This was in accord with the in vitro response of MHCC97L and HepG2 cells to hypoxia. The therapeutic effects of HAL could be enhanced by the phosphatidyl inositol 3-kinase (PI3K) inhibitor LY294002, through arrest of EMT in hepatic tumor cells. It could be useful in the development of mechanism-based combination therapies to enhance the initial antitumor response.

Expression of hypoxia-inducible factor-1alpha in liver tumors after transcatheter arterial embolization in an animal model

To examine the effect of transcatheter arterial embolization (TAE) of liver tumors on hypoxia-inducible factor-1alpha (HIF-1alpha) expression in the residual viable tumor, a total of 30 New Zealand White rabbits implanted with VX2 liver tumor were divided into 2 groups. TAE-treated group animals (n=15) were subjected to TAE with 150-250 microm polyvinyl alcohol particles. Control group animals (n=15) underwent sham embolization with distilled water. Six hours, 3 days or 7 days after TAE, the animals were sacrificed, and samples of tumor and adjacent normal liver tissue were harvested. Expression of HIF-1alpha protein was examined immunohistochemically. Real-time PCR was performed to examine the HIF-1alpha mRNA levels. Our results showed that HIF-1alpha protein was expressed in the VX2 tumors but not in the adjacent normal liver tissue. The HIF-1alpha-positive tumor cells were located predominantly at the periphery of necrotic tumor regions. The mean levels of HIF-1alpha protein were significantly higher in TAE-treated tumors than those in control tumors (P=0.002). Among the three sacrificing time points, the difference in increase in HIF-1alpha protein was significant between the two groups at the sacrificing time point of 6 h and 3 days after TAE (P=0.020, P=0.031, respectively), whereas no significant increase was noted 7 days after TAE (P=0.502). In contrast, although HIF-1alpha mRNA was expressed in TAE-treated and control VX2 tumors, there existed no significant difference in the HIF-1alpha mRNA level between the two groups (P=0.372). It is concluded that TAE of liver tumors increases the expression of HIF-1alpha at protein level in the residual viable tumor, which could be attributed to hypoxia generated by the procedure.

Hypoxia-inducible factor-1 alpha, in association with inflammation, angiogenesis and MYC, is a critical prognostic factor in patients with HCC after surgery

Background

Despite well-studied tumor hypoxia in laboratory, little is known about the association with other pathophysiological events in the clinical view. We investigated the prognostic value of hypoxia-inducible factor-1 alpha (HIF-1alpha) in hepatocellular carcinoma (HCC), and its correlations with inflammation, angiogenesis and MYC oncogene.

Methods

In a random series of 110 HCC patients, the mRNA of HIF-1alpha, inflammation related factors (COX-2, MMP7 and MMP9), angiogenesis related factors (VEGF and PDGFRA) and MYC in tumor tissue were detected by real-time RT-PCR and HIF-1alpha protein was assessed by immunohistochemistry. The correlations between HIF-1alpha mRNA and the factors mentioned previously, the relationship between HIF-1alpha and clinicopathologic features, and the prognostic value were analyzed.

Results

The expression of both HIF-1alpha mRNA and protein in HCC were independent prognostic factors for overall survival (OS) (P = 0.012 and P = 0.021, respectively) and disease-free survival (DFS) (P = 0.004 and P = 0.007, respectively) as well. Besides, the high expression of HIF-1alpha mRNA and protein proposed an advanced BCLC stage and more incidence of vascular invasion. The mRNA of HIF-1alpha had significantly positive correlations to that of COX-2, PDGFRA, MMP7, MMP9, MYC, except VEGF. In addition to HIF-1alpha, COX-2 and PDGFRA were also independent prognosticators for OS (P = 0.004 and P = 0.010, respectively) and DFS (P = 0.010 and P = 0.038, respectively).

Conclusion

HIF-1alpha in HCC plays an important role in predicting patient outcome. It may influence HCC biological behaviors and affect the tumor inflammation, angiogenesis and act in concert with the oncogene MYC. Attaching importance to HIF-1alpha in HCC may improve the prognostic and therapeutic technique.

Antisense hypoxia-inducible factor-1alpha augments transcatheter arterial embolization in the treatment of hepatocellular carcinomas in rats

Transcatheter arterial embolization (TAE) is a standard treatment for unresectable hepatic malignancies. It blocks the arterial blood supply to the tumor, but blockade of the blood supply can be short-lived as collateral blood vessels develop, leading to the failure of TAE. Here we report that intraportal delivery of adeno-associated viral (AAV) vectors expressing antisense hypoxia-inducible factor-1alpha (HIF-1alpha) (AAV-ASHIF) augments TAE to combat hepatocellular carcinoma (HCC). Intraportal delivery of AAV-ASHIF led to long-term localized expression of transgenic ASHIF in rat liver, and suppressed the growth of CBRH7919 HCC tumors established in rat liver by inhibiting the formation of neovessels and tumor cell proliferation. TAE therapy caused the necrosis and shrinkage of liver tumors; however, neovessels quickly formed and the residual tumors underwent rapid expansion. TAE enhanced tumor and liver hypoxia, which in turn upregulated expression of HIF-1alpha, vascular endothelial growth factor, glucose transporter-1, lactate dehydrogenase A, and proliferating cell nuclear antigen. Intraportal injection of AAV-ASHIF augmented the therapeutic effects of TAE and diminished its undesirable effects, resulting in extensive tumor cell death and suppression of the growth of liver tumors. In conclusion, this study has revealed that HIF-1 impedes the response of liver tumors to TAE. Antisense HIF-1alpha therapy is warranted as an approach for enhancing the efficacy of TAE to treat unresectable liver cancers.

GLUT1 expression is increased in hepatocellular carcinoma and promotes tumorigenesis

Accelerated glycolysis is one of the biochemical characteristics of cancer cells. The glucose transporter isoform 1 (GLUT1) gene encodes a key rate-limiting factor in glucose transport into cancer cells. However, its expression level and functional significance in hepatocellular cancer (HCC) are still disputed. Therefore, we aimed to analyze the expression and function of the GLUT1 gene in cases of HCC. We found significantly higher GLUT1 mRNA expression levels in HCC tissues and cell lines compared with primary human hepatocytes and matched nontumor tissue. Immunohistochemical analysis of a tissue microarray of 152 HCC cases revealed a significant correlation between Glut1 protein expression levels and a higher Ki-67 labeling index, advanced tumor stages, and poor differentiation. Accordingly, suppression of GLUT1 expression by siRNA significantly impaired both the growth and migratory potential of HCC cells. Furthermore, inhibition of GLUT1 expression reduced both glucose uptake and lactate secretion. Hypoxic conditions further increased GLUT1 expression levels in HCC cells, and this induction was dependent on the activation of the transcription factor hypoxia-inducible factor-1alpha. In summary, our findings suggest that increased GLUT1 expression levels in HCC cells functionally affect tumorigenicity, and thus, we propose GLUT1 as an innovative therapeutic target for this highly aggressive tumor.

Targeting heat-shock protein 90 improves efficacy of rapamycin in a model of hepatocellular carcinoma in mice

Hepatocellular carcinoma (HCC) remains associated with a poor prognosis, but novel targeted therapies in combination with anti-angiogenic substances may offer new perspectives. We hypothesized that simultaneous targeting of tumor cells, endothelial cells, and pericytes would reduce growth and angiogenesis of HCC, which represents a highly vascularized tumor entity. Recently, because of their anti-angiogenic properties, inhibitors of mammalian target of rapamycin (mTOR) have entered clinical trials for therapy of HCC. However, treatment with mTOR inhibitors may lead to paradoxical activation of Akt signaling in tumor cells via insulin-like growth factor-I receptor (IGF-IR)-dependent and IGF-IR-independent mechanisms. Because we have recently identified heat shock protein 90 (Hsp90) antagonists to impair both oncogenic and angiogenic signaling cascades in tumor cells, including Akt and IGF-IR, we sought to investigate whether Hsp90 blockade could improve growth-inhibitory and anti-angiogenic effects of the mTOR inhibitor rapamycin. Human HCC cells, a murine hepatoma cell line, endothelial cells (ECs), and vascular smooth muscle cells (VSMC) were employed in experiments. Results show that dual inhibition of mTOR and Hsp90 leads to effective disruption of oncogenic signaling cascades and substantially improves growth-inhibitory effects in vivo. Importantly, blocking Hsp90 abrogated the rapamycin-induced activation of Akt and of the downstream effector nuclear factor kappa-B (NF-kappaB) in HCC tumors. Furthermore, Hsp90 inhibition reduced the expression of platelet-derived growth factor-receptor-beta (PDGF-Rbeta) on VSMCs, and diminished vascular endothelial growth factor-receptor 2 (VEGFR-2) expression on ECs, which further improves the anti-angiogenic capacity of this regimen.

CONCLUSION

Blocking Hsp90 disrupts rapamycin-induced activation of alternative signaling pathways in HCCs and substantially improves the growth-inhibitory effects of mTOR inhibition in vivo. Hence, the concept of targeting tumor cells, ECs, and VSMCs by blocking Hsp90/mTOR could prove valuable for treatment of HCC.

In vivo bioluminescence imaging monitoring of hypoxia-inducible factor 1alpha, a promoter that protects cells, in response to chemotherapy

OBJECTIVE

Bioluminescence imaging is a powerful technique that has shown that hypoxia-inducible factor 1 (HIF-1), a transcription factor that protects tumor cells from hypoxia, is up-regulated in tumors after radiation therapy. We tested the hypothesis that bioluminescence imaging would successfully and noninvasively depict an increase in HIF-1 in the novel therapeutic environment of chemotherapy and that, as in radiation therapy, the underlying mechanism involves inducible nitric oxide synthase originating in macrophages. Active HIF-1 consists of alpha and beta subunits that bind to promoter sequences in many genes, including those that protect endothelial cells, promote angiogenesis, and alter metastasis and tumor cell metabolism.

MATERIALS AND METHODS

We grew 4T1 murine breast carcinoma cells with an HIF-1alpha luciferase reporter construct to 7 mm in the right rear flanks of 18 Balb-C mice. The mice were evenly randomized to receive one of the following single intraperitoneal doses: maximum tolerated dose cyclophosphamide (231.5 mg/kg), maximum tolerated dose paclitaxel (10 mg/kg), or control saline solution. Immunohistochemical analysis of tumor sections from the cyclophosphamide and control groups was performed 10 days after treatment to assess the intensity and distribution of HIF-1alpha expression, hypoxia, macrophage infiltration, and expression of macrophage-derived inducible nitric oxide synthase in tumor tissues treated with maximum tolerated dose cyclophosphamide compared with control tumors.

RESULTS

Cyclophosphamide, but not paclitaxel, significantly inhibited tumor growth and caused a significant increase in HIF-1alpha protein levels, which peaked at a 10-fold increase from baseline on day 10 after administration. In contrast, paclitaxel did not have an antitumor effect in this model and did not cause a significant increase in HIF-1alpha. Immunohistochemical analysis showed increased and more evenly dispersed levels of HIF-1alpha protein, macrophage infiltration, and expression of inducible nitric oxide synthase originating in macrophages after cyclophosphamide treatment.

CONCLUSION

We successfully monitored increased expression of a tumor protective protein in a noninvasive manner. Such monitoring may be a means of detection of resistance to therapy, and it may be possible to use the monitoring findings to alter treatment strategies in real time. The tumor microenvironment seen at immunohistochemical analysis supports the hypothesized mechanism that the cytotoxic effects of radiation therapy that attract macrophages, causing the release of macrophage-derived inducible nitric oxide synthase and production of HIF-1alpha under aerobic conditions, also underlie chemotherapy. Such noninvasive imaging may be a means to development of therapeutic strategies that prevent HIF-1 up-regulation after chemotherapy treatments.

Inhibition of mTOR enhances chemosensitivity in hepatocellular carcinoma

The present study investigated the effect of mammalian target of rapamycin (mTOR) inhibition on HCC cells in vitro and in vivo, either alone or in combination with cytotoxic agents. In vitro, HCC cell lines were exposed to RAD001, an mTOR inhibitor, either alone or in combination with cisplatin. Alone, RAD001 suppressed cell proliferation in all cell lines tested, but did not induce apoptosis. RAD001 in combination with cisplatin induced a significant increase in the number of apoptotic cells, downregulated the expression of pro-survival molecules, Bcl-2, survivin and cyclinD1, and increased the cleavage of PARP, compared to RAD001 or cisplatin alone. Transfection of p53 into the Hep3B cell line increased the sensitivity of tumor cells to cisplatin. The suppression of HCC tumor growth in vivo was enhanced by RAD001 combined with cisplatin, accompanied by a significant increase in the number of apoptotic cells in tumor tissues. This study demonstrates that inhibition of mTOR suppresses tumor growth and sensitizes tumor cells to chemocytotoxic agents.

Vascular changes in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most vascular solid tumors, in which angiogenesis plays an important role. The status of angiogenesis in HCC correlates with the disease progression and prognosis, and thus provides a potential therapeutic target. This review summarizes the vascular changes and molecular and cellular basis of angiogenesis in HCC. Development of HCC is characterized by arterialization of its blood supply and sinusoidal capillarization. Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that plays a critical role in mediating angiogenesis in HCC. The VEGF can function on various types of cells, such as endothelial cells, hepatic stellate cells, endothelial progenitor cells and hemangiocytes, to induce vascular changes in HCC. Therefore, blockade of VEGF-mediated pathways, either by anti-VEGF neutralizing antibody or tyrosine kinase inhibitors that target VEGF receptors, suppresses carcinogenesis and angiogenesis in HCC. In addition to VEGF, several other angiogenic factors in HCC have recently been identified. These factors can also regulate angiogenic processes through interaction with VEGF or VEGF-independent pathways. Despite the fact that treatment of HCC remains a tough task due to lack of effective systemic therapy, antiangiogenic therapy has already entered clinical trials in HCC patients and sheds light on a promising novel treatment for this disease.

Effect of small interference RNA targeting HIF-1alpha mediated by rAAV combined L: -ascorbate on pancreatic tumors in athymic mice

To study the effect of recombinant adeno-associated virus (rAAV) vector bearing small inference RNA (siRNA) targeting hypoxia inducible factor 1alpha (HIF-1alpha) combined L: -ascorbate on pancreatic tumors in athymic mice primarily. A cassette encoding siRNA targeting HIF-1alpha mediated by rAAV was constructed, giving rAAV-siHIF. In vitro, rAAV-hrGFP, rAAV-siHIF and L: -ascorbate which were used alone or in combination were delivered to exponentially growing MiaPaCa2 cells. Then, we examined the expression of HIF-1alpha mRNA and protein, the secretion of VEGF in MiaPaCa2 cells under hypoxic condition with Real-time PCR, Western Blot, ELISA, respectively. In vivo, MiaPaCa2 cells were inoculated subcutaneously on the back of nude mice. Nude mice with xenograft tumor were randomly divided into equal groups and were injected with rAAV-hrGFP or rAAV-siHIF or were fed with L: -ascorbate. Then, we measured the size of tumor every 3 days and drew a tumor growth curve. After 30 days, all mice were sacrificed and the tumors were dissected. At last, we examined the expression of HIF-1alpha, VEGF and CD34 by immunohistochemistry and counted micro-vessel density (MVD). In vitro, we found that rAAV-siHIF could inhibit the expression of HIF-1alpha mRNA and protein in MiaPaCa2 human pancreatic cancer cells but L: -ascorbate could only restrain the expression of HIF-1alpha protein. Moreover, rAAV-siHIF and L: -ascorbate could all inhibit the secretion of vascular VEGF. In vivo, we found that rAAV-siHIF could inhibit the growth of nude mice xenograft tumor and the expression of HIF-1alpha and VEGF and MVD while L: -ascorbate can only inhibit the growth of xenograft tumor in the early and middle stage. These results suggest that rAAV-siHIF and L: -ascorbate can inhibit the growth of nude mice xenograft tumor and HIF-1alpha could be a target of pancreatic cancer genetic and pharmacological therapy.

Cardiotrophin-1 enhances regeneration of cirrhotic liver remnant after hepatectomy through promotion of angiogenesis and cell proliferation

BACKGROUND/AIM

Hepatic resection is not applicable to a certain proportion of hepatocellular carcinoma patients owing to an insufficient liver function reserve. The present study was designed to investigate the effects of cardiotrophin-1 (CT-1) on improving the function of CCl(4)-induced cirrhotic liver remnant after major hepatectomy.

METHODS

CT-1 was administered to rats after hepatectomy according to different protocols.

RESULTS

A double-dose CT-1 protocol improved liver function, enlarged the volume of liver remnant, upregulated the expression of von Willebrand factor and increased the number of BrdU(+) or Ki-67(+) hepatocytes. Administration of CT-1 enhanced the expression of nuclear factor-kappaB (P65), vascular endothelial growth factor (VEGF), CyclinD1 and p42/44 in the liver remnant. However, the effects of CT-1 were blocked by a VEGF receptor blocker, PTK787. Although the expression of gp130, a receptor of CT-1, was downregulated in the diseased hepatocytes isolated from the cirrhotic liver, CT-1 could still stimulate the cell proliferation. CT-1 administration enhanced the expression of P65 and VEGF in the diseased hepatocytes, but the augmented P65 and VEGF expression was blocked by PTK787 administration.

CONCLUSION

Short-term administration of CT-1 could improve the function of cirrhotic liver remnant and stimulate liver regeneration through promotion of angiogenesis and cell proliferation.

Significance of CD90+ cancer stem cells in human liver cancer

This study characterized cancer stem cells (CSCs) in hepatocellular carcinoma (HCC) cell lines, tumor specimens, and blood samples. The CD90+ cells, but not the CD90(-) cells, from HCC cell lines displayed tumorigenic capacity. All the tumor specimens and 91.6% of blood samples from liver cancer patients bore the CD45(-)CD90+ population, which could generate tumor nodules in immunodeficient mice. The CD90+CD44+ cells demonstrated a more aggressive phenotype than the CD90+CD44(-) counterpart and formed metastatic lesions in the lung of immunodeficient mice. CD44 blockade prevented the formation of local and metastatic tumor nodules by the CD90+ cells. Differential gene expression profiles were identified in the CD45(-)CD90+ and CD45(-)CD90(-) cells isolated from tissue and blood samples from liver cancer patients and controls.

HIF activation protects from acute kidney injury

The contribution of hypoxia to cisplatin-induced renal tubular injury is controversial. Because the hypoxia-inducible factor (HIF) pathway is a master regulator of adaptation to hypoxia, we measured the effects of cisplatin on HIF accumulation in vitro and in vivo, and tested whether hypoxic preconditioning is protective against cisplatin-induced injury. We found that cisplatin did not stabilize HIF-1alpha protein in vitro or in vivo under normoxic conditions. However, hypoxic preconditioning of cisplatin-treated proximal tubular cells in culture reduced apoptosis in an HIF-1alpha-dependent fashion and increased cell proliferation as measured by BrdU incorporation. In vivo, rats preconditioned with carbon monoxide before cisplatin administration had significantly better renal function than rats kept in normoxic conditions throughout. Moreover, the histomorphological extent of renal damage and tubular apoptosis was reduced by the preconditional treatment. Therefore, development of pharmacologic agents to induce renal HIF might provide a new approach to ameliorate cisplatin-induced nephrotoxicity.

From molecular biology to targeted therapies for hepatocellular carcinoma: the future is now

Hepatocellular carcinoma (HCC) is characterized as a highly chemoresistant cancer with no effective systemic therapy. Despite surgical or locoregional therapies, prognosis remains poor because of high tumor recurrence or tumor progression, and currently there are no well-established effective adjuvant therapies. The molecular biology of carcinogenesis and tumor progression of HCC has been increasingly understood with intense research in recent years. Several important intracellular signaling pathways such as the Ras/Raf/Mek/Erk pathway and PI3k/Akt/mTOR pathway have been recognized, and the role of several growth factors and angiogenic factors such as EGF and VEGF has been confirmed. Effective agents targeting these molecular abnormalities have been developed and widely tested in preclinical studies of HCC cell lines or xenograft models. Several agents have entered clinical trials in HCC patients, and recent data indicated that a multikinase inhibitor targeting Ras kinase and VEGFR-2, sorafenib, is effective in prolonging survival of patients with advanced HCC. The management of advanced HCC is entering the era of molecular targeting therapy, which is of particular significance for HCC in view of the lack of existing effective systemic therapy for this cancer.

Antiangiogenic therapy enhances the efficacy of transcatheter arterial embolization for hepatocellular carcinomas

Transcatheter arterial embolization (TAE) is a well-established technique for unresectable hepatic malignancies. However, TAE can temporally halt the growth of hepatic tumors by blocking their arterial supply, but often tumors rapidly develop collateral blood vessels via angiogenesis. We have previously demonstrated that intraportal delivery of adeno-associated viral particles expressing angiostatin leads to long-term expression of angiostatin capable of inhibiting angiogenesis and suppressing the outgrowth of tumors in the liver. Thus, we hypothesize that adeno-associated virus (AAV)-mediated antiangiogenic therapy could enhance the efficacy of TAE to combat liver cancers. To achieve this objective, we engineered a recombinant AAV vector encoding rat angiostatin. Intraportal delivery of this vector led to long term and stable transgenic expression of angiostatin locally in rat hepatocytes and suppressed the growth of CBRH7919 hepatocellular carcinomas established in rat livers by inhibiting formation of neovessels. Although TAE therapy led to necrosis of liver tumors and suppressed their growth, the neovessels of tumors were rapidly reformed 3 weeks after TAE. However, intraportal injection of AAV-angiostatin inhibited the angiogenesis stimulated by TAE, synergized with TAE in suppressing growth of tumors established in livers and prolonged the survival of rats. In conclusion, these encouraging results warrant future investigation of the use of antiangiogenic therapy for enhancing the therapeutic efficacy of TAE to treat unresectable liver cancers.

Hypoxia-inducible factor-1alpha expression in experimental cirrhosis: correlation with vascular endothelial growth factor expression and angiogenesis

Angiogenesis progresses together with fibrogenesis during chronic liver injury. Hypoxia-inducible factor-1alpha (HIF-1alpha), a master regulator of homeostasis, plays a pivotal role in hypoxia-induced angiogenesis through its regulation of vascular endothelial growth factor (VEGF). The association between hypoxia, angiogenesis and VEGF expression has been demonstrated in experimental cirrhosis. However, expression of HIF-1alpha has yet to be reported. The aim of this study was to investigate the significance of HIF-1alpha expression during experimental liver fibrosis and the relationships between HIF-1alpha expression, VEGF expression and angiogenesis. Cirrhosis was induced in male Wistar rats by intraperitoneal administration of diethyl nitrosamine (DEN) (100 mg/kg, once a week). The serial sections from liver tissues were stained with anti-HIF-1alpha, anti-VEGF and anti-CD34 antibodies before being measured by light microscopy. Our results showed that HIF-1alpha expression gradually increases according to the severity of fibrosis (p<0.01). Moreover, its expression was found to be correlated with angiogenesis (r=0.916) and VEGF expression (r=0.969). The present study demonstrates that HIF-1alpha might have a role in the development of angiogenesis via regulation of VEGF during experimental liver fibrogenesis and suggests that this factor could be a potential target in the manipulation of angiogenesis in chronic inflammatory diseases of the liver.

Effect of transcatheter arterial embolization on levels of hypoxia-inducible factor-1alpha in rabbit VX2 liver tumors

PURPOSE

To test the hypothesis that transcatheter arterial embolization (TAE) of VX2 rabbit liver tumors increases the expression of hypoxia-inducible factor-1alpha (HIF-1alpha), a transcription factor that regulates the expression of pro-angiogenic genes.

MATERIALS AND METHODS

VX2 tumors were implanted in the livers of eight New Zealand white rabbits. Once tumor growth was seen at T2-weighted turbo spin-echo magnetic resonance (MR) imaging, four of the eight rabbits underwent TAE with 45-150-mum polyvinyl alcohol particles. The remaining four rabbits served as non-TAE controls. The TAE end point was stasis of antegrade blood flow. All rabbits were sacrificed for tumor harvest 2 hours after TAE. Tumor tissue and corresponding normal liver tissue in each rabbit liver were stained with anti-human HIF-1alpha monoclonal antibody and reviewed with light microscopy. Percentages of stained viable tumor and normal liver cells were compared by using the Mann-Whitney U test (alpha=0.05).

RESULTS

In eight rabbits with 24 discrete liver tumors, the mean percentage (+/-standard deviation) of positive HIF-1alpha-stained cells in the TAE group was greater than that in the control group (19%+/-7.0 vs 12%+/-8.0, respectively) (P=.05). Normal liver tissue in both the TAE and control groups showed no HIF-1alpha staining.

CONCLUSION

Although HIF-1alpha is not expressed in normal rabbit liver parenchyma-even after TAE-HIF-1alpha expression is present in implanted VX2 rabbit liver tumors and significantly increased in lesions that have undergone embolization.

Triamcinolone suppresses retinal vascular pathology via a potent interruption of proinflammatory signal-regulated activation of VEGF during a relative hypoxia

We examined the effect of triamcinolone acetonide (TA), a corticosteroid, on the relationship between vascular pathophysiology and vascular endothelial growth factor (VEGF) activation in the retina of a rat model of oxygen-induced retinopathy (OIR). OIR was induced by exposure of hyperoxia (80% oxygen) to Sprague-Dawley (SD) rats from P2 to P14 and then returned to normoxic conditions. TA was intravitreal-injected once into the right eye of OIR rats at P15. Effects of TA on vascular pathophysiology or changes of various genes in response to hypoxia and/or proinflammation under hypoxic retina were assessed by the Evans-blue method, fluorescein isothiocyanate-dextran (FITC-D) infusion, immunoblotting, and ELIZA. TA not only reduced retinal neovascularization and vascular leakage in the OIR-rat retina, but also blocked the induction of hypoxia-response proinflammatory genes before it negatively controlled VEGF activation. These findings suggest a potential that TA suppresses retinal neovascular pathophysiology via proinflammation-mediated activation of VEGF during hypoxia.

High doses of tyrosine kinase inhibitor PTK787 enhance the efficacy of ischemic hypoxia for the treatment of hepatocellular carcinoma: dual effects on cancer cell and angiogenesis

The present study aimed to investigate the therapeutic efficacy of combining vascular endothelial growth factor (VEGF) receptor blockade using tyrosine kinase inhibitor PTK787 with hypoxia for the treatment of hepatocellular carcinoma (HCC). The in vivo effects of the treatments were determined in a rat orthotopic HCC model, in which hypoxia was generated by hepatic artery ligation (HAL). Compared with HAL alone, PTK787 combined with HAL significantly prolonged the animal survival, reduced the tumor size, induced more tumor tissue necrosis and apoptosis, and down-regulated the expression of von Willebrand factor. The mechanism was explored in vitro using murine HCC and endothelial cell lines, respectively. PTK787 combined with hypoxia decreased the expression of VEGF and VEGF receptors in both cell lines and suppressed the cell viability by induction of cell cycle arrest and promotion of apoptosis. Up-regulation of cleaved form caspase-9 and down-regulation of Bcl-2 and cyclin D1 were detected with the combined treatment. Hypoxia sensitized endothelial cells to the inhibitory effect of PTK787 on forming tubular-like structure. The motility of tumor cells was inhibited by hypoxia and the combined approach, with down-regulation of Rac1, Rho, and phosphorylated Akt expression. However, in the endothelial cells, the combined treatment inhibited the hypoxia-enhanced cell motility, with suppressed Rac1, Rho, and phosphorylated Akt expression. In conclusion, PTK787 combined with hypoxia achieved a better therapeutic efficacy than hypoxia alone through enhancing hypoxia-induced antitumor cell effect and preventing the activation of angiogenic process.

Up-regulation of tumor susceptibility gene 101 protein in ovarian carcinomas revealed by proteomics analyses

Small GTPase RAS plays a critical role in cellular signaling and oncogenic transformation. Proteomics analysis of genetically defined human ovarian cancer models identified the tumor susceptibility gene 101 (TSG101) as a downstream target of RAS oncogene. Mechanistic studies revealed a novel post-translational regulation of TSG101 through the RAS/RAF/MEK/MAPK signaling pathway and downstream molecules p14(ARF)/HDM2. Immunoanalysis using ovarian cancer samples and microtissue array revealed elevated TSG101 levels in human ovarian carcinomas. Silencing of TSG101 by short interfering RNA in ovarian cancer cells led to growth inhibition and cell death. Concurrent with the apparent growth-inhibitory effect, the levels of the CBP/p300-interacting transactivator with ED-rich tail 2 (CITED2) and hypoxia-inducible factor 1alpha (HIF-1alpha), as well as its cellular activity, were markedly reduced after TSG101 knockdown. These results demonstrate that TSG101 is important for CITED2- and HIF-1alpha-mediated cellular regulation in ovarian carcinomas.

Clinicopathological study of scirrhous hepatocellular carcinoma

BACKGROUND AND AIMS

Scirrhous hepatocellular carcinoma (SHCC) is characterized by diffuse fibrosis of the tumor, however, its clinicopathological features are not fully clarified. This study aimed to clarify the clinicopathological features of SHCC.

METHODS

Among 546 consecutively resected HCC without preoperative anticancer therapies, 25 SHCC were selected for the study and compared with 521 cases without scirrhous as the control.

RESULTS

SHCC accounted for 4.6% of cases. On diagnostic imagings, SHCC was frequently misdiagnosed as cholangiocarcinoma (CC), combined HCC-CC or metastatic carcinoma. Overall survival rate was significantly higher than the control. The average (+/-SD) tumor size of SHCC was 3.4 +/- 1.8 cm without significant difference to the control. The majority of SHCC (88%) were located close to the liver capsule. SHCC was characterized by stellate fibrosis (84%), no encapsulation (100%), no necrosis and hemorrhage (100%), intratumoral portal tracts (80%), remarkable lymphocyte infiltration (84%), clear cell change (84%), and hyaline bodies (52%). The number of alpha-smooth muscle actin-positive myofibroblast-like cells (activated stellate cells) in the tumor was about three times more than that in the control. Regarding the developmental mechanism of scirrhous change, a close correlation with unique tumor location and activation of stellate cells was suggested.

CONCLUSIONS

SHCC presents with characteristic clinicopathological features and the recognition of SHCC is important for both clinicians and pathologists.

Suppression of hypoxia inducible factor-1alpha (HIF-1alpha) by YC-1 is dependent on murine double minute 2 (Mdm2)

Inhibition of HIF-1alpha activity provides an important strategy for the treatment of cancer. Recently, 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1) has been identified as an anti-HIF-1alpha drug in cancer therapy with unclear molecular mechanism. In the present study, we aimed to investigate the effect and mechanism of YC-1 on HIF-1alpha in a hepatocellular carcinoma cell line under hypoxic condition, which was generated by incubating cells with 0.1% O(2). The phenotypic and molecular changes of cells were determined by cell proliferation assay, apoptosis assay, luciferase promoter assay, and Western blot analysis. YC-1 arrested tumor cell growth in a dose-dependent manner, whereas it did not induce cell apoptosis. Hypoxia-induced upregulation of HIF-1alpha was suppressed by YC-1 administration. YC-1 inhibited HIF-1alpha protein synthesis under normoxia and affected protein stability under hypoxia. YC-1 suppressed the expression of total and phosphorylated forms of murine double minute 2 (Mdm2), whereas this inhibitory effect was blocked by overexpression of Mdm2. In conclusion, YC-1 suppressed both protein synthesis and stability of HIF-1alpha in HCC cells, and its inhibitory effects on HIF-1alpha were dependent on Mdm2.

Anterior approach for major right hepatic resection

We review the history, indications, and latest modifications of the surgical technique of the anterior approach for right hepatectomy for massive tumors. The anterior approach provides a "no-touch" technique in resecting large right-lobe tumors, reduces bleeding volume, decreases the chance of iatrogenic rupture of tumors, and probably prolongs survival.

Angiogenesis and antiangiogenic therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascular tumor characterized by neovascularization, which plays an important role in the growth and progression of HCC. Angiogenesis provides a target for novel prognostic and therapeutic approaches to HCC. Assessment of microvessel density using immunohistochemical staining for specific endothelial cell markers such as CD34 has been shown to provide prognostic information independent of conventional pathological parameters in HCC patients. Recent studies have unveiled the important angiogenic factors involved in the regulation of angiogenesis in HCC, although the exact molecular pathways are far from clear. Current data suggest that vascular endothelial growth factor (VEGF) plays a critical role in angiogenesis of HCC. Tumor expression of VEGF has been shown to correlate with tumor invasiveness and prognosis in patients with HCC. VEGF is an important molecular target for antiangiogenic therapy. Studies in animal models have demonstrated the efficacy of antiangiogenic agents such as anti-VEGF antibody and antagonists of VEGF receptors in suppressing hepatocarcinogenesis and growth of HCC. Antiangiogenic therapy has already entered clinical trials in HCC patients and holds the promise of providing an effective novel treatment for HCC, which is of great clinical significance because there is no existing effective systemic therapy for HCC.

Induction of the hypoxia-inducible factor system by low levels of heat shock protein 90 inhibitors

The heterodimeric hypoxia-inducible factor-1 (HIF-1) is involved in key steps of tumor progression and therapy resistance and thus represents an attractive antitumor target. Because heat shock protein 90 (HSP90) plays an important role in HIF-1alpha protein stabilization and because HSP90 inhibitors are currently being tested in clinical phase I trials for anticancer treatment, we investigated their role as anti-HIF-1alpha agents. Surprisingly, low-dose (5-30 nmol/L) treatment of HeLa cells with three different HSP90 inhibitors (17-AAG, 17-DMAG, and geldanamycin) increased HIF-1-dependent reporter gene activity, whereas higher doses (1-3 micromol/L) resulted in a reduction of hypoxia-induced HIF-1 activity. In line with these data, low-dose treatment with HSP90 inhibitors increased and high-dose treatment reduced hypoxic HIF-1alpha protein levels, respectively. HIF-1alpha protein stabilized by HSP90 inhibitors localized to the nucleus. As a result of HSP90-modulated HIF-1 activity, the levels of the tumor-relevant HIF-1 downstream targets carbonic anhydrase IX, prolyl-4-hydroxylase domain protein 3, and vascular endothelial growth factor were increased or decreased after low-dose or high-dose treatment, respectively. Bimodal effects of 17-AAG on vessel formation were also seen in the chick chorioallantoic membrane angiogenesis assay. In summary, these results suggest that dosage will be a critical factor in the treatment of tumor patients with HSP90 inhibitors.

Hypoxia-inducible factor modulates tubular cell survival in cisplatin nephrotoxicity

Hypoxia-inducible factor (HIF)-1 is a transcription factor mediating cellular response to hypoxia. Although it is expressed in tubular cells of the ischemic kidney, its functional role is not fully clarified in the pathological context. In this study, we investigated a role of HIF in tubular cell apoptosis induced by cisplatin. HIF-1alpha was expressed in tubular cells in the outer medulla 3 days after cisplatin (6 mg/kg) administration. With the in vivo administration of cobalt to activate HIF, the number of apoptotic renal tubular cells became much smaller in the outer medulla, compared with the vehicle group. We also examined the functional role of HIF-1 in vitro using immortalized rat proximal tubular cells (IRPTC). In hypoxia, IRPTC that express dominant-negative (dn) HIF-1alpha showed impaired survival in cisplatin injury at variable doses (25-100 microM, 24 h), which was not obvious in normoxia. The observed difference in cell viability in hypoxia was associated with the increased number of apoptotic cells in dnHIF-1alpha clones (Hoechst 33258 staining). Studies on intracellular signaling revealed that the degree of cytochrome c release, dissipation of mitochondrial membrane potentials, and caspase-9 activity were all more prominent in dnHIF-1alpha clones than in control IRPTC, pointing to the accelerated signaling of mitochondrial pathways. We propose that HIF-1 mediates cytoprotection against cisplatin injury in hypoxic renal tubular cells, by reducing the number of apoptotic cells through stabilization of mitochondrial membrane integrity and suppression of apoptosis signaling. A possibility was suggested that activation of HIF-1 could be a new promising therapeutic target for hypoxic renal diseases.