Nonangiogenic function of VEGF and enhanced radiosensitivity of HeLa cells by inhibition of VEGF expression.

Vascular endothelial growth factor (VEGF) plays an important role in the initiation and regulation of angiogenesis in various tumor tissues. Recently, several therapeutic approaches based on the inhibition of VEGF function during angiogenesis. However, VEGF function in cervical cancer may not be limited to angiogenesis, and VEGF signaling may be important for the ability of these tumor cells to evade apoptosis and progress towards invasive and metastatic diseases. In our study, VEGF expression was knocked down using plasmid-based RNA interference (RNAi) and detected in cervical carcinoma cells using real-time RT-PCR to screen the best RNA interference plasmid and reveal the VEGF expression level by radiation. Cell apoptosis and tumor xenografts in nude mice were measured by flow cytometry and immunohistochemistry, respectively, to further verify the possibility of enhancing apoptosis and radiosensitivity of cervical carcinoma cells by inhibition of VEGF expression. VEGF expression was significantly inhibited and the apoptosis was efficiently increased by RNAi. Moreover, the expression of VEGF was increased in HeLa cells in vivo and in vitro only by radiation. Increased apoptotic cell death and knockdown of VEGF expression in HeLa cells indicated increased cellular sensitivity to radiation. The data suggested that inhibited VEGF expression enhances radiosensitivity in cervical cancer therapy.

Transforming growth factor-beta-1 is a serum biomarker of radiation-induced pneumonitis in esophageal cancer patients treated with thoracic radiotherapy: preliminary results of a prospective study.

OBJECTIVE: To examine the relationship between cytokine levels of transforming growth factor-beta-1 (TGF-ß1), interleukin-1 beta (IL-1ß), and angiotensin-converting enzyme (ACE) in the plasma of esophageal carcinoma patients and radiation-induced pneumonitis (RP). MATERIALS AND METHODS: Sixty-three patients with esophageal carcinoma were treated with three-dimensional conformal radiotherapy (RT) using the Elekta Precise treatment planning system with a prescribed dose of 50-70 Gy. Dose-volume histograms were collected from three-dimensional conformal RT to determine the volume percentage of the lung received V5, V10, V20, and the normal tissue complication probability. RP was diagnosed based on computed tomography imaging, respiratory symptoms, and signs. The severity of radiation-induced lung toxicity was determined using the Lent-Soma scale defined by the Radiation Therapy Oncology Group. Plasma samples obtained before RT, during RT (at 40 Gy), and at 1 day, 1 month, and 3 months after RT were assayed for TGF-ß1, IL-1ß, and ACE levels by enzyme-linked immunosorbent assay. RESULTS: From the 63 patients, 17 (27%) developed RP, and 13 (21%) had RP of grade I and four (6%) had grade II or higher. We found plasma TGF-ß1 levels were elevated in the patients that had RP when compared with the other 46 patients who did not have RP. The plasma IL-1ß levels were not changed. The ACE levels were significantly lower in the 17 patients with RP compared to the 46 patients without RP throughout the RT. As expected, RP is associated with a higher dose of irradiation (>60 Gy); no other factors, including dose-volume histogram, age, sex, smoking status, location of tumor, and methods of treatment, are associated with RP. CONCLUSION: Elevated plasma TGF-ß1 levels can be used as a marker for RP.