Advancement and prospects of tumor gene therapy / 癌症

Gene therapy is one of the most attractive fields in tumor therapy. In past decades, significant progress has been achieved. Various approaches, such as viral and non-viral vectors and physical methods, have been developed to make gene delivery safer and more efficient. Several therapeutic strategies have evolved, including gene-based (tumor suppressor genes, suicide genes, antiangiogenic genes, cytokine and oxidative stress-based genes) and RNA-based (antisense oligonucleotides and RNA interference) approaches. In addition, immune response-based strategies (dendritic cell- and T cell-based therapy) are also under investigation in tumor gene therapy. This review highlights the progress and recent developments in gene delivery systems, therapeutic strategies, and possible clinical directions for gene therapy.

Effect of ZD6474 on the proliferation of imatinib-resistant K562 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of tyrosine kinase inhibitor ZD6474 (Vandetanib) on the proliferative inhibition of K562 cells and its derived imatinib-resistant K562/G cells and its mechanism.</p><p><b>METHODS</b>Imatinib-resistant K562/G cells were obtained by culturing cells in gradually increasing concentrations of imatinib. The changed factors related to drug-resistance were tested by Western blot. ZD6474 and imatinib affected K562/G and parental K562 cells proliferation were analyzed by WST assay. Flow cytometry was used to analyze cell cycle. Direct inhibition of Src activity by ZD6474 was measured by a colorimetric ELISA assay with recombinant human Src kinase.</p><p><b>RESULTS</b>10 µmol/L imatinib failed to inhibit K562/G cells proliferation or induce cell cycle arrest. Compared with that in parental K562 cells, there were marked high levels of p-Src and Src protein in K562/G cells. The expression of Bcl-2 and p-STAT3 also increased in K562/G cells. After 48 hours incubation, the IC(50) values of ZD6474 in K562 and K562/G cells were 1.61 µmol/L and 3.18 µmol/L, respectively. ZD6474 treatment caused accumulation of cells in the G(0)/G(1) fraction and cell apoptosis in K562 and K562/G cells. ZD6474 decreased the expression of p-Src and Src at post-transcriptional level. Moreover, ZD6474 increased the ratio of Bax/Bcl-2 and decreased the expression of p-STAT3 at the same concentration for inducing apoptosis.</p><p><b>CONCLUSIONS</b>ZD6474 is effective in inhibiting the proliferation of imatinib-resistant K562/G cells and parental K562 cells, and induces their apoptasis by significant inhibition of Src kinase activity. Our study provides a reliable experimental basis for chronic myeloid leukemia treatment with ZD6474.</p>

Recent progress in nanotechnology for cancer therapy / 癌症

The application of nanotechnology significantly benefits clinical practice in cancer diagnosis, treatment, and management. Especially, nanotechnology offers a promise for the targeted delivery of drugs, genes, and proteins to tumor tissues and therefore alleviating the toxicity of anticancer agents in healthy tissues. This article reviews current nanotechnology platforms for anticancer drug delivery, including polymeric nanoparticles, liposomes, dendrimers, nanoshells, carbon nanotubes, superparamagnetic nanoparticles, and nucleic acid-based nanoparticles [DNA, RNA interference (RNAi), and antisense oligonucleotide (ASO)] as well as nanotechnologies for combination therapeutic strategies, for example, nanotechnologies combined with multidrug-resistance modulator, ultrasound, hyperthermia, or photodynamic therapy. This review raises awareness of the advantages and challenges for the application of these therapeutic nanotechnologies, in light of some recent advances in nanotechnologic drug delivery and cancer therapy.

Bone marrow stromal cells transfected with ciliary neurotrophic factor gene ameliorates the symptoms and inflammation in C57BL/6 mice with experimental allergic encephalomyelitis / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the anti-inflammatory effect of bone marrow stromal cells (MSCs) transfected with recombinant adenovirus-mediated ciliary neurotrophic factor (CNTF) gene in C57BL/6 mice with experimental allergic encephalomyelitis (EAE).</p><p><b>METHODS</b>An adenovirus vector containing CNTF gene Ad-CNTF-IRES-GFP was constructed and transfected in the MSCs (MSC-CNTF). After examination of CNTF expression, the transfected cells were transplanted in C57BL/6 mice with MOG 35-55-induced EAE, which were monitored for the changes in the symptoms scores. The levels of tumor necrosis factor-alpha (TNF-alpha), inteferon-gamma (IFN-gamma), interleukin-12P35 (IL-12P35), and IL-10 in the peripheral blood of the mice were detected, and the number of MSC-CNTF cells in the spleen and spinal cord was counted. CD3+ T cell infiltration and TNF-alpha and IFN-gamma expressions in the lesions were also observed after the cell transplantation.</p><p><b>RESULTS</b>CNTF gene transfection resulted in significantly increased CNTF expression in the MSCs. The mice receiving MSC-CNTF transplantation exhibited significantly improved symptoms with shortened disease course and lessened disease severity. The cell transplantation also resulted in significantly decreased peripheral blood TNF-alpha levels, ameliorated CD3+T cell infiltrations and lowered TNF-alpha expression in the lesions, while the levels of IFN-gamma underwent no significant changes.</p><p><b>CONCLUSION</b>Transplantation of CNTF gene-transfected MSCs results in decreased peripheral blood TNF-alpha and IFN-gamma levels and reduced inflammatory cells, CD3-positive cells and TNF-alpha expression in the lesion of EAE, therefore providing better effect than MSCs in relieving the symptoms of EAE in mice.</p>

Inhibition of tumor growth in xenografted nude mice with adenovirus-mediated endostatin gene comparison with recombinant endostatin protein / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Inhibition of tumor growth by endostatin has been shown to be an effective strategy in cancer therapy in mice. However, its widespread application has been hampered by difficulties in a large-scale production of the recombinant endostatin protein, rapid loss bioactivity of the protein, and the cumbersome daily administration. These limitations could be resolved by in vivo delivery and expression of the endostatin gene. In this study, we observed the effect and advantage of endostatin gene therapy mediated by a recombinant adenoviral vector (Ad/hEndo) on the growth of hepatocellular carcinoma BEL-7402 xenografted tumors, comparison with recombinant endostatin protein.</p><p><b>METHODS</b>Hepatocellular carcinoma BEL-7402 cells were inoculated subcutaneously in the flank of Balb/c nude mice. Nine days after tumor cell inoculation, animals were given a cycle of four courses of intra-tumoral injections of Ad/hEndo of 5 x 10(8) pfu (low-dose group) and 1 x 10(9) pfu (high-dose group) at intervals of six days, respectively. Recombinant human endostatin protein (rhEndo) was administrated daily subcutaneously at a dose of 10 mg.kg(-1).d(-1) at a site nearby the tumor for ten days. The expression of endostatin mRNA in tumor tissue was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) after Ad/hEndo injection. Dynamic changes of concentration of endostatin protein in tumor tissue were quantitated by enzyme-linked immunosorbent assay (ELISA).</p><p><b>RESULTS</b>After 4 courses of treatment, the tumor growth rates of high-dose treated group with 1 x 10(9) pfu of Ad/hEndo were inhibited by 42.26% compared with the Ad/LacZ control group (P = 0.001) and by 46.26% compared with the NIH buffer control group (P = 0.003), respectively. However, in this study, Ad/hEndo at low dose of 5 x 10(8) pfu failed to demonstrate significant inhibition of tumor growth, compared with control groups. After daily administration of recombinant human endostatin protein (rhEndo) for 9 days, the ratio of T/C (rhEndo group versus PBS group) was less than 47%. However, two days after rhEndo treatment ceased, the ratio of T/C was more than 50%. The peak of expression of endostatin mRNA in tumor tissue was at 2 or 3 days after administration intratumorally with Ad/hEndo of 1 x 10(9) pfu and gradually dropped undetectable by day 7. Dynamic analysis of endostatin concentration in tumor tissue showed that the highest level of mRNA is up at the third day after injection, and dropped to basal level three weeks later.</p><p><b>CONCLUSIONS</b>Endostatin gene therapy mediated by a recombinant adenoviral vector had significantly inhibited the growth of hepatocellular carcinoma BEL-7402 xenografted tumors at a high dose of 1 x 10(9) pfu compared with other groups. The analysis of dynamic expression of endostatin in vivo indicated that Ad/hEndo had acquired a high-level, relatively long-term expression in vivo and bioactivity capability.</p>

Inhibitive effects of recombinant adenovirus-mediated human endostatin on the growth of human hepatocellular carcinoma xenograft in nude mice / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the inhibitive effect on the growth of hepatocellular carcinoma (HCC) xenografted in nude mice by adenovirus-mediated human endostatin gene.</p><p><b>METHODS</b>The expression efficiency of endostatin was examined after ECV-304 cells infected with Ad/hEndo by western blot. The hepatoma BEL-7402 cells were injected into Balb/c nude mice to detect the inhibition of Ad/hEndo on the growth of HCC xenografted in nude mice. The expression of endostatin mRNA in tumor tissue was analyzed with RT-PCR, and its distribution in vivo was also analyzed.</p><p><b>RESULTS</b>High level expression of endostatin achieved in infected ECV-304 cells by western blot. Ad/hEndo significantly inhibited the growth of xenografted BEL-7402 tumors (F=4.061, P<0.05). The intratumoral microvessel density (MVD) decreased significantly in the treated mice (6.88+/-1.08 vs 13.60+/-1.71, t=9.216, P<0.01). The expression of endostatin mRNA in tumor tissue was detected by RT-PCR in 3 days after administration intratumorally with Ad/hEndo and almost disappeared in 7 days. Endostatin mRNA was mainly located in tumor tissue with a higher concentration than that in heart, lung, spleen and liver after Ad/hEndo administration.</p><p><b>CONCLUSION</b>Adenovirus-mediated human endostatin gene can be expressed efficiently in vitro and in vivo, and significantly inhibit the growth of BEL-7402 xenografted tumors in nude mice.</p>