尼美舒利对乳腺癌细胞放射增敏作用的研究；Radiosensitizing Effect of Nimesulide on Breast Cancer Cells and Corresponding Mechanisms

目的综述近年来banoxantrone(AQ4N)作为肿瘤治疗增敏药物在国外的研究进展,为国内开发和应用AQ4N提供参考。方法分析、归纳、总结近年来发表的相关文献。结果与结论AQ4N本身对细胞没有毒性,在乏氧条件下经还原酶的催化生成活性药物AQ4,后者通过抑制乏氧细胞中的拓扑异构酶Ⅱ活性而杀死肿瘤乏氧细胞。AQ4N选择性作用于乏氧细胞,与富氧细胞毒性剂如放疗或化疗联合应用,疗效显著。

Effect of p53 on lung carcinoma cells irradiated by carbon ions or X-rays

The study is to investigate the feasibility and advantages of heavy ion beams on radiotherapy. The cellular cycle and apoptosis, cell reproductive death and p53 expression evaluated with flow cytometry, clonogenic survival assays and Western blot analysis were examined in lung carcinoma cells after exposure to 89.63 MeV/u carbon ion and 6 MV X-ray irradiations, respectively. The results showed that the number colonyforming assay of A549 was higher than that of H1299 cells in two radiation groups; A549 cellular cycle was arrested in G(2)/M in 12 It and the percentage of apoptosis ascended at each time point of carbon ion radiation with doses, the expression of p53 upregulated with doses exposed to X-ray or carbon ion. The cell number in G(2)/M of H1299 and apoptosis were increasing at all time points with doses in C-12(6+) ion irradiation group. The results suggested that the effects of carbon ions or X rays irradiation on lung carcinoma cells were different, C-12(6+) ion irradiation could have more effect on upregulating the expression of p53 than X-ray, and the upregulated expression of p53 might produce the cellular cycle G(2)/M arrested, apoptosis increasing; and p53 gene might affect the lung cancer cells radiosensitivity.

Inhibiting Survivin Expression Increases The Radiosensitivity of Human Hepatoma HepG2 Cells to High-LET Radiation

The influence of survivin expression on the radiosensitivity of tumor cells to high linear energy transfer (LET) radiation is investigated. Survivin-specific short-interfering RNA (siRNA) oligonucleotides were synthesized based on the survivin sequence provided by GenBank. Human hepatoma HepG2 cells were transfected with survivin-specific siRNA to inhibit its expressions. It was found that the transfection with surviving-specific siRNA increased the levels of G2/M arrest and the apoptotic rates induced by radiation in HepG2 cells. After exposure to high-LET carbon ions, a reduced clonogenic survival effect was observed in the cells treated with siRNA. These results show that survivin plays a key role in mediating the radioresistance of cells to high-LET radiation.

Prostate cancer cell-specific VEGF siRNA delivery system using cell targeting peptide conjugated polyplexes

A polymeric gene carrier was developed to deliver vascular endothelial growth factor (VEGF) small interfering RNA (siRNA) for prostate cancer cells in a target-specific manner. Prostate cancer-binding peptide (PCP) was conjugated with polyethylenimine (PEI) via a poly(ethylene glycol) (PEG) linker (PEI-PEG-PCP). The PEI-PEG-PCP conjugate could effectively condense siRNA to form stable polyelectrolyte complexes (polyplexes) with an average diameter of approximately 150 nm in an aqueous solution. VEGF siRNA/PEI-PEG-PCP polyplexes exhibited significantly higher VEGF inhibition efficiency than PCP-unmodified polycationic carriers (PEI-PEG or PEI) in human prostate carcinoma cells (PC-3 cells). The enhanced gene silencing activity of VEGF siRNA/PEI-PEG-PCP was maintained even under serum conditions, owing to the steric stabilization of the polyplexes with hydrophilic PEG grafts. Confocal microscopic studies revealed that the siRNA/PEI-PEG-PCP polyplexes were delivered into PC-3 cells in a PCP ligand-specific manner.

Rhein induces apoptosis and cell cycle arrest in human hepatocellular carcinoma BEL-7402 cells

Rhein, an anthraquinone derivative of rhubarb, inhibits the proliferation of various human cancer cells. In this paper, we focused on studying the effects of rhein on human hepatocelluar carcinoma BEL-7402 cells and further understanding the underlying molecular mechanism in an effort to make the potential development of rhein in the treatment of cancers. Using MTT assay and flow cytometry, we demonstrate a critical role of rhein in the suppression of BEL-7402 cell proliferation in a concentration- and time-dependent manner. The increase of apoptosis rate was observed after incubation of BEL-7402 cells with rhein at 50-200 mu M for 48 hours, and the cells exhibit typical apoptotic features including cellular morphological change and chromatin condensation. Moreover, rhein-induced cell cycle S-phase arrest. Additionally, after rhein treatment, expression levels of c-Myc gene were decreased, while those of caspase-3 gene were increased in a dose-dependent manner by using real-time PCR assay. The results demonstrate for the first time that cell cycle S-phase arrest is one of the mechanisms of rhein in inhibition of BEL-7402 cells. Rhein plays its role by inducing cell cycle arrest via downregulation of oncogene c-Myc and apoptosis through the caspase-dependent pathway. It is expected that rhein will be effective and useful as a new agent in hepatocelluar carcinoma treatment in the future.