Recently, biologically active compounds isolated from plants used in herbal medicine have been the center of interest. Deoxypodophyllotoxin (DPT), structurally closely related to the lignan podophyllotoxin, was found to be a potent antitumor and antiproliferative agent, in several tumor cells, in vitro. However, DPT has not been used clinically yet because of the lack of in vivo studies. This study is the first report demonstrating the antitumor effect of DPT on MDA-MB-231 human breast cancer xenografts in nude mice. DPT, significantly, inhibited the growth of MDA-MB-231 xenograft in BALB/c nude mice. The T/C value (the value of the relative tumor volume of treatment group compared to the control group) of groups treated with 5, 10, and 20 mg/kg of intravenous DPT-HP-β-CD was 42.87%, 34.04% and 9.63%, respectively, suggesting the positive antitumor activity of DPT. In addition, the antitumor effect of DPT-HP-β-CD (20 mg/kg) in human breast cancer MDA-MB-231 xenograft was more effective than etoposide (VP-16) (20 mg/kg) and docetaxel (20 mg/kg). These findings suggest that this drug is a promising chemotherapy candidate against human breast carcinoma.

HIV-1 particle assembly is driven by oligomerization of the Gag polyprotein precursor in infected cells. Translation of the full-length viral RNA results in the synthesis of large amounts of Gag molecules which oligomerize upon the combined interactions of its C-terminal NC domain with the genomic RNA and of its N-terminal myristate and matrix basic residues with cellular membranes. HIV assembly has been studied during the past two decades mostly by means of biochemical techniques on transfected or infected cells as well as in vitro using purified Gag molecules. More recently, understanding the mechanisms of viral assembly moved a big step forward due to the utilization of fluorescently labeled viral proteins, notably Gag, and of fluorescent microscopy techniques able to track single viral particles. In this chapter, we will summarize recent imaging data on HIV-1 Gag assembly at the level of the plasma membrane where viral particles bud in the form of cell-free viruses or can be transmitted to adjacent naïve cells through virological synapses.