A pH-sensitive liposome formulation of a peptidomimetic-Dox conjugate for targeting HER2 + cancer

Cancer treatment faces the challenge of selective delivery of the cytotoxic drug to the desired site of action to minimize undesired side effects. The liposomal formulation containing targeting ligand conjugated cytotoxic drug can be an effective approach to specifically deliver chemotherapeutic drugs to cancer cells that overexpress a particular cell surface receptor. This research focuses on the in vitro and in vivo studies of a peptidomimetic ligand attached doxorubicin for the HER2 positive lung and breast cancer cells transported by a pH-dependent liposomal formulation system for the enhancement of targeted anticancer treatment. The selected pH-sensitive liposome formulation showed effective pH-dependent delivery of peptidomimetic-doxorubicin conjugate at lower pH conditions mimicking tumor microenvironment (pH-6.5) compared to normal physiological conditions (pH 7.4), leading to the improvement of cell uptake. In vivo results revealed the site-specific delivery of the formulation and enhanced antitumor activity with reduced toxicity compared to the free doxorubicin (Free Dox). The results suggested that the targeting ligand conjugated cytotoxic drug with the pH-sensitive liposomal formulation is a promising approach to chemotherapy.

Antimycobacterial activity of peptide conjugate of pyridopyrimidine derivative against Mycobacterium tuberculosis in a series of in vitro and in vivo models

New pyridopyrimidine derivatives were defined using a novel HTS in silico docking method (FRIGATE). The target protein was a dUTPase enzyme (EC 3.6.1.23; Rv2697) which plays a key role in nucleotide biosynthesis of Mycobacterium tuberculosis (Mtb). Top hit molecules were assayed in vitro for their antimycobacterial effect on Mtb H37Rv culture. In order to enhance the cellular uptake rate, the TB820 compound was conjugated to a peptid-based carrier and a nanoparticle type delivery system (polylactide-co-glycolide, PLGA) was applied. The conjugate had relevance to in vitro antitubercular activity with low in vitro and in vivo toxicity. In a Mtb H37Rv infected guinea pig model the in vivo efficacy of orally administrated PLGA encapsulated compound was proven: animals maintained a constant weight gain and no external clinical signs of tuberculosis were observed. All tissue homogenates from lung, liver and kidney were found negative for Mtb, and diagnostic autopsy showed that no significant malformations on the tissues occurred.