title: Spatane diterpinoid from the brown algae, Stoechospermum marginatum induces apoptosis via ROS induced mitochondrial mediated caspase dependent pathway in murine B16F10 melanoma cells.
abstract: Spatane diterpinoids isolated from the brown marine algae Stoechospermum marginatum were known to have cytotoxic effects in human cancerous cell lines and murine melanoma cells; the underling apoptotic mechanism of diterpinoids still remains unclear so far. Thus, in the present study, the apoptotic mechanism of a spatane diterpinoid, 5(R), 19-diacetoxy-15,18(R and S), dihydro spata-13, 16(E)-diene (DDSD) was investigated mainly in B16F10 melanoma cells because they were most susceptible to DDSD than THP1, U937, COLO205, and HL60 cells. The treatment of B6F10 cells with DDSD resulted in morphological alterations, nuclear condensation, and DNA fragmentation, which leads to cell growth inhibition in a concentration-dependent manner. Data indicate that DDSD induced the generation of ROS, consequentially caused alteration in Bax/Bcl-2 ratio that disrupted the inner mitochondrial transmembrane potential (ΔΨm) resulting in cytochrome c redistribution to the cytoplasm and activation of caspase-mediated apoptotic pathway. Flow cytometric analysis clearly indicated that the DDSD inducing phosphatidylserine externalization and mediated "S-phase" arrest in cell cycle. In addition, results also found that DDSD induced apoptosis through deregulating PI3K/AKT signaling pathway. The anti-tumor activity of DDSD was evaluated in C57BL/6 mice bearing B16F10 melanoma. It effectively inhibited tumor growth (volume and weight) in a dose dependent manner, yet without apparent toxic effects. Morphology and apoptotic status of tumor tissues in the treated mice were assessed by microscopy and TUNEL assay, respectively. Our study shows a therapeutic potential of DDSD for the treatment of malignant melanoma and a new source of anticancer drugs. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Division of Biology, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: Loka Reddy
authors.initials: LR
authors.lastname: Velatooru
authors.affiliation: Division of Natural Product, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: Chinna Babu
authors.initials: CB
authors.lastname: Baggu
authors.affiliation: Division of Biology, CSIR-Indian Institute of Chemical Technology, Hyderabad, Telangana, India.
authors.forename: Venkateswara Rao
authors.initials: VR
authors.lastname: Janapala
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D004224:Diterpenes / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D008546:Melanoma, Experimental / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D000459:Phaeophyceae / Q000737:chemistry; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D012867:Skin / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology
chemical_list: D000970:Antineoplastic Agents; D004224:Diterpenes; D017382:Reactive Oxygen Species; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D020169:Caspases
keywords: anticancer; apoptosis; brown algae; reactive oxygen species; spatane diterpinoid