An arresten-derived anti-angiogenic peptide triggers apoptotic cell death in endothelial cells.

BACKGROUND: In recent years, anti-angiogenic peptides have received considerable attention as candidates for cancer treatment. Arresten is an angiogenesis inhibitor that cleaves from the α1 chain of type IV collagen and stimulates apoptosis in endothelial cells. We have recently indicated that a peptide corresponding to the amino acid 78 to 86 of arresten, so-called Ars, prevented the migration and tube formation of HUVECs and the colon carcinoma growth in mice significantly. The current study aimed to determine whether induction of apoptotic cell death in endothelial cells is one of the biochemical mechanisms of this anti-angiogenic peptide. METHODS AND RESULTS: This hypothesis was assessed using the MTT assay, cell cycle analysis, Annexin V-FITC/PI staining, BCL2, CASP8, CASP9, p53, and CDKN2A gene expression studies as well as evaluating apoptosis in tumor tissues by TUNEL assay. Results demonstrated that 40 µM of Ars significantly stimulated 46.2% of early and late apoptosis in HUVECs compared to 13.6% in the untreated cells and did not significantly alter the cell cycle distribution. Moreover, BCL2 and CASP8 were down-regulated, while CASP9 and p53 were up-regulated in endothelial cells. CDKN2A gene expression, the regulator of G1 cell cycle arrest, was not significantly altered. CONCLUSIONS: It might be suggested that Ars induced apoptosis in endothelial cells through the mitochondrial pathway and had no effect on the cell cycle. Besides, Ars induced apoptosis significantly in vivo. However, further studies are required to confirm the detailed molecular mechanism of Ars, this peptide has the potential to be optimized for clinical translations.

Combination Therapy in Cancer: Doxorubicin in Combination with an N-terminal Peptide of Endostatin Suppresses Angiogenesis and Stimulates Apoptosis in the Breast Cancer.

The combination of chemotherapy drugs with angiogenesis inhibitors improves response and survival and reduces the cytotoxic side effects and drug resistance in patients compared to chemotherapy alone. Here, we investigated the efficacy of the concomitant administration of doxorubicin and a peptide derived from the N-terminal domain of Endostatin (called ES-SS) in the 4T1 mammary carcinoma tumor model. Tumor-bearing mice were divided into the control and three treatment groups, including ES-SS, doxorubicin, and the combination. Injections were performed daily for two weeks and tumor volumes were measured during the treatment. Immunohistochemical analysis of Ki-67, CD31, CD34, Bcl-2, p53 expression, and TUNEL assay were performed on tumor tissues at the end of treatment. Besides, molecular dynamics and docking simulations were performed. It was demonstrated that tumor growth was inhibited in mice treated with peptide plus doxorubicin more significantly than in each treatment alone (P<0.05). No weight loss or adverse effects were observed. Moreover, combination therapy was more effective in tumor angiogenesis suppression and apoptosis stimulation (P<0.05). Docking simulations by ClusPro server demonstrated that ES-SS binds to integrin α5ß1, Transglu-taminase 2, and Matrix metalloproteinase 2 with more negative binding energy and hydrogen bonds compared to the native peptide. Generally, we proposed that ES-SS can augment the therapeutic efficacy of doxorubicin through angiogenesis prevention and apoptosis induction in breast tumor. Owing to the advantages of peptides to recombinant proteins or monoclonal antibodies, further preclinical and clinical evaluations of this combination strategy are worth taking into consideration.

A novel sulfamethoxazole derivative as an inhibitory agent against HSP70: A combination of computational with in vitro studies.

In the current study, a novel derivative of sulfamethoxazole (a sulfonamide containing anti-biotic) named ZM-093 (IUPAC name: (E)-4-((4-(bis(2-hydroxyethyl)amino)phenyl)diazenyl)-N-(5-methylisoxazole-3-yl)benzenesulfonamide) was synthesized via common diazotization-coupling reactions from sulfamethoxazole and subsequently characterized through NMR/FT-IR spectroscopy. After evaluation, the compound was geometrically optimized at the DFT level of theory with BL3YP method and 6/31++G (d,p) basis set and from the optimized structure, several molecular descriptors important in the biological reactivity of the compound, such as global reactivity parameters, molecular electrostatic potential, average local ionization energy, and drug-likeness features of the compound were computationally analyzed. The experimental in vitro investigations of the interaction between ZM-093 and heat shock protein 70 (HSP70), a protein that is highly expressed in several types of cancers, exhibited a significant inhibitory effect against the chaperone activity of HSP70 for the titled compound (P-value < 0.01) and the comparison between the experimental studies with the mentioned computational analysis, as well as molecular docking, illustrated that ZM-093 may inhibit HSP70 through binding to its substrate-binding domain. Finally, by taking all the previous results into account, a new method for assessing the inhibitory activity of ligand to HSP70 is introduced based on protonography, a recently developed method that is dependent on the catalytic activity of carbonic anhydrase on polyacrylamide gel electrophoresis.