Therapeutic advances targeting tumor angiogenesis in pancreatic cancer: Current dilemmas and future directions.

Pancreatic cancer (PC) is one of the most lethal malignancies, which is generally resistant to various treatments. Tumor angiogenesis is deemed to be a pivotal rate-determining step for tumor growth and metastasis. Therefore, anti-angiogenetic therapy is a rational strategy to treat various cancers. However, numerous clinical trials on anti-angiogenetic therapies for PC are overwhelmingly disappointing. The unique characteristics of tumor blood vessels in PC, which are desperately lacking and highly compressed by the dense desmoplastic stroma, are reconsidered to explore some optimized strategies. In this review, we mainly focus on its specific characteristics of tumor blood vessels, discuss the current dilemmas of anti-angiogenic therapy in PC and their underlying mechanisms. Furthermore, we point out the future directions, including remodeling the abnormal vasculature or even reshaping the whole tumor microenvironment in which they are embedded to improve tumor microcirculation, and then create therapeutic vulnerabilities to the current available therapeutic strategies.

Phase I clinical trial of continuous infusion of tyroserleutide in patients with advanced hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is usually diagnosed in advanced stage, which causes difficulty of using surgical treatment. Previous studies demonstrated that tyroserleutide (YSL), an immunologically active tripeptide compound, could suppress the proliferation and tumor formation of some liver cancer cell lines. We aimed to investigate the feasibility and toxicity of continuous administration of YSL by a portable infusion pump to patients with advanced HCC and its biologically effective but non-toxic doses used in outpatient setting. Forty patients (12 in stage 1, 28 in stage 2, total 10 treated in each dose cohort) were treated with YSL 6, 12, 18, or 24 mg/day lasting for 5 days. No treatment-related mortality was observed. The overall response rates were 25% (3/12) and 7.2% (2/28) in stages 1 and 2, respectively. The median 6-month overall survival (OS) in stage 1 was 75, 64, and 41 days for 6, 18, and 24 mg/day groups, respectively; all patients survived in the 12 mg/day group. The median OS in stage 2 was 68, 72, and 60 days for 12, 18, and 24 mg/day groups, respectively; all survived in the 6 mg/day group. The most common adverse reactions were abnormal liver function (59/107) and hemogram (22/107). The dose-limiting toxicities of 24 mg/day group contained abdominal distention (1/10), sicchasia (1/10), hyponatremia (1/10), myocardiac ischemia (1/10), and abnormal hemogram (6/10). We conclude that the continuous administration of YSL by portable infusion pump was well tolerated. Treatment responses of doses 6 and 12 mg/day were better than other two groups. Further studies of continuous infusion of YSL to determine its efficacy are warranted.

A novel tripeptide, tyroserleutide, inhibits irradiation-induced invasiveness and metastasis of hepatocellular carcinoma in nude mice.

Previous studies have demonstrated that tyroserleutide (YSL) inhibits tumor growth in an animal model of hepatocellular carcinoma (HCC). However, its effects on HCC metastasis are still not fully understood. To examine YSL as a novel agent to prevent HCC metastasis, a metastatic human HCC orthotopic nude mouse model of MHCC97L was used. The antitumor and antimetastasis effects of YSL were also evaluated in combination with radiation. Hypoxia and epithelial-mesenchymal transition (EMT)-related molecules were studied. YSL inhibited MHCC97L cell invasion in vitro with or without irradiation. YSL did not significantly inhibit tumor growth but decreased pulmonary metastasis and prolonged life-span for more than 40 days, which correlated with down-regulation of matrix metalloproteinase-2. Radiotherapy inhibited early-stage tumor growth and promoted tumor hypoxia. The re-implanted tumor volume in the radiotherapy group was not significantly different from the control, in which the incidence of lung metastasis increased after radiotherapy (6/6 versus 3/6, P = 0.046); however, YSL inhibited the growth of re-implanted tumor after radiotherapy. Furthermore, YSL at 160 or 320 µg/kg/day almost completely inhibited lung metastasis induced by irradiation (1/6 versus 6/6, P = 0.002 for both dosages). YSL down-regulated hypoxia-inducible factor 1α (HIF-1α) and transmembrane protease serine 4 (TMPRSS4), and inhibited EMT was associated with the antimetastasis capability of YSL. Our data suggest that YSL inhibits the enhanced invasiveness and metastatic potential of HCC induced by irradiation through down-regulation of HIF-1α and TMPRSS4 and inhibition of EMT. YSL may have potential as a new antimetastasis agent for radiotherapy.

High expression of macrophage colony-stimulating factor-1 receptor in peritumoral liver tissue is associated with poor outcome in hepatocellular carcinoma after curative resection.

BACKGROUND: Macrophage colony-stimulating factor 1 receptor (CSF-1R) expression in hepatocellular carcinoma (HCC) and its prognostic values are unclear. This study evaluated the prognostic values of the intratumoral and peritumoral expression of CSF-1R in HCC patients after curative resection. METHODS: Tissue microarrays containing material from cohort 1 (105 patients) and cohort 2 (32 patients) were constructed. Immunohistochemistry was performed and prognostic values of these and other clinicopathological data were evaluated. The CSF-1R mRNA level was assessed by quantitative real-time polymerase chain reaction in cohort 3 (52 patients). RESULTS: Both the CSF-1R density and its mRNA level were significantly higher in peritumoral liver tissue than in the corresponding tumor tissue. CSF-1R was distributed in a gradient in the long-distance peritumoral tissue microarray, with its density decreasing as the distance from the tumor margin increased. High peritumoral CSF-1R was significantly associated with more intrahepatic metastases and poorer survival. Peritumoral CSF-1R was an independent prognostic factor for both overall survival and time to recurrence and affected the incidence of early recurrence. However, intratumoral CSF-1R did not correlate with any clinicopathological feature. Peritumoral CSF-1R was also associated with both overall survival and time to recurrence in a subgroup with small HCCs (< or =5 cm). CONCLUSIONS: Peritumoral CSF-1R is associated with intrahepatic metastasis, tumor recurrence, and patient survival after hepatectomy, highlighting the critical role of the peritumoral liver milieu in HCC progression. CSF-1R may become a potential therapeutic target for postoperative adjuvant treatment.

Protein expression profiling of vascular endothelial growth factor and its receptors identifies subclasses of hepatocellular carcinoma and predicts survival.

PURPOSE: To examine expression profile and prognostic significance of vascular endothelial growth factor (VEGF) and its receptors in hepatocellular carcinoma (HCC) and peritumoral tissue. METHODS: Expression of VEGF-A, VEGF-C, and VEGF receptor 1(VEGFR-1), VEGFR-2, and VEGFR-3 in tumor and peritumoral liver tissue was studied by immunohistochemistry in a tissue microarray from 107 patients with HCC. Unsupervised hierarchical cluster analyses were conducted to identify relevant clusters. RESULTS: Staining of VEGF-A, VEGF-C, VEGFR-2, and VEGFR-3 was mostly found on the tumor cells and peritumoral hepatocytes, but VEGFR-1 was mostly expressed in stromal cells. In most of the cases, the expression of VEGF-A, VEGFR-1, VEGFR-2, and VEGFR-3 in was higher in peritumoral liver tissue, while VEGF-C expression was higher in tumor. Unsupervised hierarchical clustering analysis identified four prognostically different clusters, of which cluster A was classified into the "poor prognosis group," and the other three clusters were classified into the "good prognosis group" (P = 0.047). Further analysis with a set of seven markers reproduced the same four cluster groups with significantly different recurrence free probability (RFP) (P = 0.018), and the low RFP group was associated with more intrahepatic satellite lesions. Multivariate analysis showed that classification defined by seven biomarkers was of prognostic significance (P = 0.000). CONCLUSIONS: Expression of VEGF and its receptors was higher in peritumoral tissue than in tumor in HCC. Seven biomarkers predicted patients' RFP, which consisted of tumoral expression of VEGF-A, VEGFR-1, and VEGF-C as well as peritumoral expression of VEGF-A, VEGFR-1, VEGFR-2, and VEGFR-3.

[Effects of pioglitazone on the morphology and the expression of connective tissue growth factor of transforming growth factor beta-induced rat hepatic stellate cells in vitro].

OBJECTIVES: To observe the effects of pioglitazone on morphological changes and connective tissue growth factor (CTGF) expression of the transforming growth factor beta (TGF b)-induced rat hepatic stellate cells (HSCs) in vitro, and to investigate the anti-fibrotic mechanism of pioglitazone. METHODS: Cultured rat HSCs were divided into a no-treatment control group, a TGF b-treated group, and a TGFb plus different dosage pioglitazone-treated group. The morphological changes of the cultured HSCs were observed. The expression of CTGF was assessed by immunohistochemistry and flow cytometry. The level of collagen type III in the culture supernatant was measured by ELISA. RESULTS: TGFb induced morphological changes, and increased the expressions of CTGF and collagen type III of the HSCs (P less than 0.05). Pioglitazone prevented the TGFb induced morphological changes of the HSCs. The expression of CTGF and the levels of collagen type III in the pioglitazone group were lower than the TGF b-treated group (P less than 0.05). This prevention effect was dose-dependent (P less than 0.05). CONCLUSION: Pioglitazone blocks the excretion of CTGF and collagen type III of cultured HSCs, preventing the development of liver fibrosis.

Effect of endotoxin on fibronectin synthesis of rat primary cultured hepatocytes.

AIM:To investigate the effect of endotoxin on liver fibrosis and further define the role of hepatocytes in production of fibronectin in primary liver cell culture by endotoxin.METHODS:After isolation and seeding of hepatocytes, the obtained cells were added to various doses (0, 5, 10, 15 and 20mg/L) of LPS treated culture media. The cells were collected and counted at various periods (0, 12, 24, 48, 72, 96, 120h).The concentrations of fibronectin were tested by electrophoresis. RESULTS:The fibronectin levels tended to increase with prolongation of culture time. There was a sharp increase after 72h in 10 or 15 LPS treated group. The peak level of fibronectin was above 20mg/L. However, cell proliferation was inhibited during the course.Cell number of untreated control group (4.6 ± 0.1 10(6)) was about three fold that of 20 LPS treated group (1.6 ± 0.2 10(6)) at 120h.CONCLUSION:Hepatocytes have a potent ability to produce fibronectin stimulated by endotoxin, suggesting that hepatocytes might participate in the process of liver fibrosis.