5-Methoxyisatin N(4)-Pyrrolidinyl Thiosemicarbazone (MeOIstPyrd) Restores Mutant p53 and Inhibits the Growth of Skin Cancer Cells, In Vitro.

A series of novel thiosemicarbazone derivatives containing 5-methoxy isatin were designed and synthesized with modification on N(4) position. Derivatives considering structure-activity relationship have been designed and synthesized by condensing thiosemicarbazide with 5-methoxy isatin. The synthesized compounds were characterized by elemental analysis, FT-IR spectroscopy, UV-visible spectroscopy, NMR (1H, 13C) spectroscopy, mass spectrometry, and a single-crystal study. Biological evaluation of the synthesized compounds revealed that MeOIstPyrd is the most promising compound against skin cancer cell line, A431, with an IC50 value of 0.9 µM. In addition, MeOIstPyrd also exhibited low toxicity against the normal human fibroblast and the human embryonic kidney 293 cell line, HLF-1, and HEK293, respectively. Furthermore, the mechanistic study revealed that MeOIstPyrd efficiently inhibited cell proliferation, migration, and spheroid formation by activating the mitochondrial intrinsic apoptotic pathway. MeOIstPyrd also induces DNA damage and activates p53 irrespective of the p53 status. It increases the half-life of p53 and stabilizes p53 by phosphorylating it at ser15. Moreover, MeOIstPyrd was found to bind to MDM2 in the p53 sub-pocket and, therefore, block p53-MDM2 interaction. Our result exhibited potential anticancer activity of MeOIstPyrd in the A431 cell line and its ability in restoring mutant p53, which is an interesting and promising strategy for cancer therapeutics.

Knockdown of CSNK2ß suppresses MDA-MB231 cell growth, induces apoptosis, inhibits migration and invasion.

Breast cancer is the most common cancer among women worldwide. Among different types of breast cancer known, treatment of triple-negative breast cancer is a major challenge because of its aggressiveness and poor prognosis; thus, identification of specific drivers is required for targeted therapies of breast cancer malignancy. Protein Casein Kinase (CSNK) is a serine/threonine kinase that exists as a tetrameric complex consisting of two catalytic (α and /or α') and two regulatory ß subunits. CSNK2ß can also function independently without catalytic subunits and exist as a distinct population in cells. This study aims to elucidate the role of Casein Kinase 2ß (CSNK2ß) gene in cell proliferation, cell cycle, migration and apoptosis of triple-negative breast cancer MDA-MB-231 cells. The silencing of CSNK2ß in MDA-MB-231 cells resulted in decreased cell viability and colony formation. Cell cycle analysis showed a significant arrest of cells in G2M phase. Hoechst and CM-H2DCFDA staining showed nuclear condensation and augmented intracellular reactive oxygen species (ROS) production. Furthermore, silencing of CSNK2ß in MDA-MB-231 cells modulated the apoptotic machinery- BAX, Bcl-xL, and caspase 3; autophagy machinery-Beclin-1 and LC3-1; and inhibited the vital markers (p-ERK, c-Myc, NF-κB, E2F1, PCNA, p38-α) associated with cell proliferation and DNA replication pathways. In addition, knockdown of CSNK2ß also affected the migration potential of MDA-MB-231, as observed in the wound healing and transwell migration assays. Altogether, the study suggests that CSNK2ß silencing may offer future therapeutic target in triple-negative breast cancer.

Isaria tenuipes Peck, an entomopathogenic fungus from Darjeeling Himalaya: Evaluation of in-vitro antiproliferative and antioxidant potential of its mycelium extract.

BACKGROUND: Isaria tenuipes is one of the potent species in the members of the genus Isaria, which is well reported to possess multiple bioactive substances of therapeutic importance. Therefore, an in vitro experimental study was carried to evaluate the bioactivities of the crude methanolic extract from the mycelium of this fungus. METHODS: The fungus was authenticated through morphological characters and the species discrepancy was resolved using the nuclear rDNA ITS sequence. The methanolic extract was fingerprinted by FTIR. The antioxidant components in terms of total phenols and flavonoids were determined as gallic acid and quercetin equivalents respectively. Antioxidant activities of the methanolic extract was assessed using 1, 1-diphenyl-2-picrylhydrazyl (DPPH), 2, 2/-azinobis-(3-ethylbenzthiazoline-6-sulphonic acid) radical cation (ABTS0+), Fe2+chelating activity, and hydroxyl radical scavenging assays. Cytotoxicity of the extract was determined by [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] (MTT) assay on three cancer cell lines: HeLa, HepG2, and PC3. Apoptosis was further studied by propidium iodide (PI) and Annexin-V/PI staining flow cytometric analysis. Anti-proliferation capacity was studied by colony-forming assay. RESULTS: In the present study total phenol content of the dried methanol extract was 148.09 ± 3.51µg gallic acid equivalent/mg and flavonoid was 9.02±0.95 µg quercetin/mg. The antioxidant activities of methanol-water extract (8:2 v/v) from cultured mycelia of I. tenuipes investigated and evaluated with 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay revealed IC50 value of 5.04mg/ml with an inhibition rate of 74.77% at 10mg/ml and with an iron-chelating assay the chelating ability was recorded to be 86.76% where the IC50 value was 4.43 mg/ml. In comparison among the antioxidant assays, 2,2/-azinobis-(3-ethylbenzthiazoline-6-sulphonic acid) radical cation (ABTS0+) and hydroxyl assay exhibited radical scavenging rate of 44.42% and 49.82% respectively at a concentration of 10 mg/ml. The IC50 value of the extract in MTT assay was 43.45µg/ml with HeLa cells, 119.33µg/ml with PC3 cells, and 125.55µg/ml with HepG2 cells. CONCLUSION: In this study, it can be concluded that the crude methanolic extract exhibited potent antioxidant and antiproliferative activities suggesting natural antioxidative and antiproliferative agents.

2-Pyridineformamide N(4)-ring incorporated thiosemicarbazones inhibit MCF-7 cells by inhibiting JNK pathway.

In an effort to develop a more potent anticancer therapeutic agent, a series of 2-pyridineformamide thiosemicarbazones (R = H, 4-CH3, 5-F, 6-CH3 and ) have been synthesized and evaluated for their anti-cancer activities against the cancer cells MCF-7 (breast cancer cell line), A-431 and A375 (epidermoid carcinoma cell line), and HeLa (cervical cancer cell line) using MTT assay. All these 2-pyridineformamide thiosemicarbazones exhibited anti-proliferative activities towards these cell lines. 5FAmPyrr possess most profound effects against MCF-7 cells with IC50 of 0.9 µM. In flow cytometry using Propidium Iodide, 5FAmPyrr was found to induce cell death significantly in a dose dependent manner (100 nM-3 µM) and inhibited colony formation of MCF-7 cells. This compound induced pro-apoptotic protein Bax and inhibited anti apoptotic protein Bcl-2 as well as both c-Jun and Jun N-terminal kinase (abbreviated as JNK) in concentration dependent manner. Further pro-caspase 3 and PARP were inhibited by 5FAmPyrr at concentration of 3 µM. The results suggest that 5FAmPyrr exhibit anticancer potency and induced cell death by inhibiting MAPK signaling and inducing intrinsic apoptotic pathway. All these indicate that 2-pyridineformamide thiosemicarbazones could be developed as future therapeutics agents to treat cancer.

CRISPR/Cas9 System: A Bacterial Tailor for Genomic Engineering.

Microbes use diverse defence strategies that allow them to withstand exposure to a variety of genome invaders such as bacteriophages and plasmids. One such defence strategy is the use of RNA guided endonuclease called CRISPR-associated (Cas) 9 protein. The Cas9 protein, derived from type II CRISPR/Cas system, has been adapted as a versatile tool for genome targeting and engineering due to its simplicity and high efficiency over the earlier tools such as ZFNs and TALENs. With recent advancements, CRISPR/Cas9 technology has emerged as a revolutionary tool for modulating the genome in living cells and inspires innovative translational applications in different fields. In this paper we review the developments and its potential uses in the CRISPR/Cas9 technology as well as recent advancements in genome engineering using CRISPR/Cas9.