Dolastatin, along with Celecoxib, stimulates apoptosis by a mechanism involving oxidative stress, membrane potential change and PI3-K/AKT pathway down regulation

• Published in: Biochimica et biophysica acta Vol. 1830; no. 11; pp. 5142 - 5156
• Main Authors: Piplani, Honit, Rana, Chandan, Vaish, Vivek, Vaiphei, Kim, Sanyal, S.N.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.11.2013
• Subjects: adenosine triphosphate; Adenosine Triphosphate - metabolism; AKT; animal models; Animals; antineoplastic agents; apoptosis; Apoptosis - drug effects; binding sites; Binding Sites - drug effects; Binding Sites - genetics; calcium; carcinogenesis; Celecoxib; cell cycle; Cell Cycle Proteins - genetics; Cell Cycle Proteins - metabolism; colon; Colonic Neoplasms - drug therapy; Colonic Neoplasms - genetics; Colonic Neoplasms - metabolism; colorectal neoplasms; cyclins; Cyclooxygenase 2 Inhibitors - pharmacology; Depsipeptides - pharmacology; Dolastatin; Down-Regulation - drug effects; Egr-1; flow cytometry; fluorescence; gene expression regulation; genes; Male; membrane potential; Membrane Potential, Mitochondrial - drug effects; Membrane Potential, Mitochondrial - genetics; mitochondrial membrane; Molecular docking; molecular models; molluscs; oxidative stress; Oxidative Stress - drug effects; Oxidative Stress - genetics; phosphatidylinositol 3-kinase; Phosphatidylinositol 3-Kinases - genetics; Phosphatidylinositol 3-Kinases - metabolism; PI3-K; pro-apoptotic proteins; prostaglandin synthase; protein synthesis; Proto-Oncogene Proteins c-akt - genetics; Proto-Oncogene Proteins c-akt - metabolism; Pyrazoles - pharmacology; Rats; Rats, Sprague-Dawley; reactive oxygen species; Reactive Oxygen Species - metabolism; signal transduction; Signal Transduction - drug effects; spectroscopy; Sulfonamides - pharmacology; transcription factors; tumor suppressor proteins; Egr-1; PI3-K; AKT; Celecoxib; Dolastatin; Molecular docking
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2013.07.011

Phosphoinositide 3-kinase (PI3-K) is an important regulator of oncogenesis and apoptosis in various types of cancers including colon cancer. A combinatorial strategy of using Cyclooxygenase-2 inhibitor, Celecoxib and Dolastatin, a linear peptide from marine mollusks of Indian Ocean origin has shown anti-neoplastic effects in colon cancer in a rat model. The signal transduction pathway of PI3-K/AKT and the downstream signaling proteins had been studied in an early stage of colon carcinogenesis (DMH induced) by gene and protein expression, apoptotic studies by colonocyte apoptotic bleb assay, intracellular calcium level by fluorescence spectrometry, mitochondrial membrane potential by Rhodamine 123 flow cytometry and Reactive oxygen species measurement. Molecular docking analysis was employed to study the interaction of oncogenic proteins and the ligand, Celecoxib and Dolastatin. Apoptotic cell index was lowered with DMH while both the drugs increased it and inhibited PI3-K and AKT expression. Docking studies revealed both the proteins targeted by the drugs via an ATP binding site. An increased expression of GSK-3β, pro-apoptotic protein Bad, transcription factor Egr-1, tumor suppressor protein PTEN while a downregulation of G1-associated cell cycle protein, Cyclin D1 and increased intracellular calcium as well as reactive oxygen species were observed. Also, the number of cells having a higher mitochondrial membrane potential was lowered. Celecoxib and Dolastatin inhibited the tumor development through regulation of the PI3-K/AKT pathway which can act as a novel target for these drugs. The anti-cancer properties of Dolastatin, a peptide isolated from marine mollusks in colorectal cancer is shown. •Dolastatin and Celecoxib are effective in stimulating apoptosis in colon cancer.•PI3-K/AKT pathway down regulation and Egr-1 up regulation during chemoprevention•Dolastatin and Celecoxib up regulates Bad and downregulates Cyclin D1.•Mechanisms involve increased calcium load and reactive oxygen species.•Change in mitochondrial membrane potential follows.