Pentamidine is an inhibitor of PRL Phosphatases and also inhibits synthesis of DNA, RNA and protein.
Description :
Pentamidine is known experimentally to interfere with numerous cellular processes. Specifically, Pentamidine has been shown to bind to DNA in a nonintercalative manner and appears to preferentially bind to kinetoplast DNA in trypanosomes. Additionally, Pentamidine may inhibit RNA polymerase and ribosomal function, as well as nucleic acid, protein, phospholipid, and polyamine synthesis. Pentamidine also inhibits certain proteases, including trypsin, and impairs cellular oxygen consumption. [1] Pentamidine has a potent in vitro antiprotozoal activity. Pentamidine displays cytotoxic activity against L. infantum promastigotes with IC50 of 2.5 μM. 2.5 μM Pentamidine induces early programmed cell death in 49.6% of L. infantum promastigotes. 2.5 μM Pentamidine induces a notorious decrease in promastigotes in both G1 and S phases relative to the control-untreated samples (G1:77.0 vs 15.0%; S:11.0 vs 2.4% for control- and pentamidine-treated promastigotes, resp). Pentamidine is able to bind with calf-thymus DNA (CT-DNA) and induces conformational changes in the DNA double helix. Pentamidine also binds with ubiquitin to modifiy the β-cluster of ubiquitin. [2] Pentamidine is an inhibitor of phosphatase of regenerating liver (PRLs). 1 μg/mL of Pentamidine complete inhibits the activity of recombinant PTP1B in dephosphorylating a phos-photyrosine peptide. 10 μg/mL of Pentamidine completely inhibits the activities of recombinant PRL-1, PRL-2 and PRL-3 in dephosphorylating a phosphotyrosine peptide substrate. Incubation with Pentamidine (1 μg/mL) for 48 h reduces the activity of intracellular PRL phosphatases in transfected NIH3T3 cells by more than 85%. 10 μg/mL Pentamidine completely inhibits the growth of melanoma cell line (WM9), prostate carcinoma cell line (DU145 and C4–2), ovarian carcinoma cell line (Hey), colon carcinoma cell line (WM480), and lung carcinoma cell line (A549) which all express endogenous PRLs. [3]
Palbociclib(150 mg/kg. p.o.) produces rapid Colo-205 colon carcinoma xenografts regressions and a corresponding tumor growth delay. Palbociclib (150 mg/kg, p.o.) induces complete tumor stasis and cell kill in MDA-MB-435 breast carcinoma. Palbociclib (150 mg/kg) also induces significant tumor regression in mice bearing the SF-295 glioblastoma xenografts, and in ZR-75-1 breast and PC-3 prostate tumor models (complete suppression of tumor growth). Palbociclib (150 mg/kg) suppresses Rb Ser780 phosphorylation in MDA-MB-435 breast carcinoma over the full 24-hour period. Palbociclib (150 mg/kg) down-regulates expression of four E2F-regulated genes CDC2, CCNE2, TK1, and TOP2A in Colo-205 carcinoma xenografts[1]. Palbociclib also rapidly inhibits myeloma tumor growth[2].