Magic™ Anti-HIV type 1 TAT Polyclonal antibody

Lung cancer patients with human immunodeficiency virus (HIV) have a poorer prognosis than do patients without HIV infection. HIV1 Tat is a secreted viral protein that penetrates the plasma membrane and interacts with a number of proteins in non-HIV-infected cells. The loss of function of Tat-interacting protein 30 (TIP30) has been linked to metastasis in non-small cell lung cancer (NSCLC). However, it is unknown how the interaction of HIV1 Tat with TIP30 regulates the metastasis of NSCLC cells. In this study, the overexpression of TIP30 decreased tumor growth factor--induced epithelial-to-mesenchymal transition (EMT) and invasion of NSCLC cells, whereas the knockdown of TIP30 promoted EMT, invasion and stemness. Exposure to recombinant HIV1 Tat proteins promoted EMT and invasion. A mechanistic study showed that the interaction of HIV1 Tat with TIP30 blocked the binding of TIP30 to importin-, which is required for the nuclear translocation of Snail. Indeed, the loss of TIP30 promoted the nuclear translocation of Snail. In vivo studies demonstrated that the overexpression of TIP30 inhibited the metastasis of NSCLC cells. In contrast, the coexpression of HIV1 Tat and TIP30 diminished the inhibitory effect of TIP30 on metastasis. Immunohistochemistry confirmed that TIP30 overexpression reduced the nuclear localization of Snail, whereas the coexpression of HIV1 Tat and TIP30 increased nuclear Snail in metastatic tumors. In conclusion, the binding of HIV1 Tat to TIP30 enhanced EMT and metastasis by regulating the nuclear translocation of Snail. Targeting Tat-interacting proteins may be a potential therapeutic strategy to prevent metastasis in NSCLC patients with HIV infection.

Sufficient levels of gene expression are required for effective gene therapy. One of the major obstacles in gene therapy is the low transgene expression obtained from currently available vector systems. To address this issue, we employed a transcriptional amplifier strategy in a single construct to enhance transgene expression. In the amplifier vectors (pHi-1 and pHi-2), the strong CMV promoter was used to drive a transcriptional factor, Tat, which could transactivate a second promoter (HIV1 LTR or HIV2 LTR) located in the same construct driving the gene of interest. Using the human interleukin - 2 (IL-2) cytokine gene, our data showed that the pHi-1/2 amplifier vectors could produce significantly higher IL-2 levels in human lung cancer cells (A549) and breast cancer cells (MCF-7) than that obtained by directly using the CMV promoter alone. Injection of pHi-2-IL-2-modified Lewis Lung (LL/2) tumor clones led to significantly slower tumor growth and longer survival in mice compared to those injected with either CMV promoter driven IL-2 clones or the parental tumor cells. Our results demonstrated that the transcriptional amplifier-based expression cassettes could be very useful in applications where high levels of gene expression are difficult to achieve.