Anticancer peptides mechanisms, simple and complex.

Peptide therapy has started since 1920s with the advent of insulin application, and now it has emerged as a new approach in treatment of diseases including cancer. Using anti-cancer peptides (ACPs) is a promising way of cancer therapy as ACPs are continuing to be approved and arrived at major pharmaceutical markets. Traditional cancer treatments face different problems like intensive adverse effects to patient's body, cell resistance to conventional chemical drugs and in some worse cases the occurrence of cell multidrug resistance (MDR) of cancerous tissues against chemotherapy. On the other hand, there are some benefits conceived for peptides usage in treatment of diseases specifically cancer, as these compounds present favorable characteristics such as smaller size, high activity, low immunogenicity, good biocompatibility in vivo, convenient and rapid way of synthesis, amenable to sequence modification and revision and there is no limitation for the type of cargo they carry. It is possible to achieve an optimum molecular and functional structure of peptides based on previous experience and bank of peptide motif data which may result in novel peptide design. Bioactive peptides are able to form pores in cell membrane and induce necrosis or apoptosis of abnormal cells. Moreover, recent researches have focused on the tumor recognizing peptide motifs with the ability to permeate to cancerous cells with the aim of cancer treatment at earlier stages. In this strategy the most important factors for addressing cancer are choosing peptides with easy accessibility to tumor cell without cytotoxicity effect towards normal cells. The peptides must also meet acceptable pharmacokinetic requirements. In this review, the characteristics of peptides and cancer cells are discussed. The various mechanisms of peptides' action proposed against cancer cells make the next part of discussion. It will be followed by giving information on peptides application, various methods of peptide designing along with introducing various databases. Future aspects of peptides for employing in area of cancer treatment come as conclusion at the end.

Novel 5-(nitrothiophene-2-yl)-1,3,4-Thiadiazole Derivatives: Synthesis and Antileishmanial Activity against promastigote stage of Leishmania major.

In this study, a series of novel compounds based on 5-(5-nitrothiophene-2-yl)-1,3,4-thiadiazole possessing (het) aryl thio pendant at C-2 position of thiadiazole ring is developed and evaluated as antileishmanial agents using MTT colorimetric assay. 10 New compounds containing aryl and heteroaryl derivatives, started from thiophene-2-carbaldehyde in five steps, were synthesized in good to excellent yields and characterized by 1H-NMR, 13C-NMR, and IR spectroscopy. Through the compounds 6a-j, methylimidazole containing derivative 6e was recognized as the most active compound against L. major promastigotes exhibiting IC50 values of 11.2µg/mL and 7.1µg/mL after 24 and 48 h, respectively. This compound is > 4 fold more effective than Glucantime as a standard drug (IC50 = 50 µg/mL after 24 h and 25 µg/mL after 48 h).