Anticancer potential of pyrrole (1, 2, a) pyrazine 1, 4, dione, hexahydro 3-(2-methyl propyl) (PPDHMP) extracted from a new marine bacterium, Staphylococcus sp. strain MB30.

Marine bacterium, strain MB30 isolated from the deep sea sediment of Bay of Bengal, India, exhibited antimicrobial activity against human pathogenic bacteria. Based on the 16S rRNA sequence homology and subsequent phylogenetic tree analysis, the strain MB30 was identified as Staphylococcus sp. The bioactive metabolite produced by the strain MB30 was purified through silica gel column chromatography and preparative HPLC. Purified metabolite was further characterized by FT-IR, LC-MS and NMR analyses. On the basis of spectroscopic data, the metabolite was identified as pyrrole (1, 2, a) pyrazine 1, 4, dione, hexahydro 3-(2-methyl propyl) (PPDHMP). The PPDHMP exhibited in vitro anticancer potential against lung (A549) and cervical (HeLa) cancer cells in a dose-dependent manner with the IC50 concentration of 19.94 ± 1.23 and 16.73 ± 1.78 µg ml(-1) respectively. The acridine orange (AO)/ethidium bromide (EB) and 4,6-diamidino-2-phenylindole dihydrochloride (DAPI) staining of the IC50 concentration of PPDHMP-treated cancer cells exhibited an array of morphological changes such as nuclear condensation, cell shrinkage and formation of apoptotic bodies. The PPDHMP-treated cancer cells induced the progressive accumulation of fragmented DNA in a time-dependent manner. Based on the flow cytometric analysis, it has become evident that the compound was also effective in arresting the cell cycle at G1 phase. Further, the Western blotting analysis confirmed the down-regulation of cyclin-D1, cyclin dependent kinase (CDK-2), anti-apoptotic Bcl-2 family proteins (Bcl-2 and Bcl-xL), activation of caspase-9 and 3 with the cleavage of PARP. The PPDHMP-treated cancer cells also showed the inhibition of migration and invasive capacity of cancer cells. In the present investigation, for the first time, we have reported the extraction, purification and characterization of an anticancer metabolite, PPDHMP from a new marine bacterium, Staphylococcus sp. strain MB30.

Anti-leukemic, anti-lung, and anti-breast cancer potential of the microbial polyketide 2, 4-diacetylphloroglucinol (DAPG) and its interaction with the metastatic proteins than the antiapoptotic Bcl-2 proteins.

The microbial polyketide, 2, 4-diacetylphloroglucinol (DAPG), exhibited a broad-spectrum of anti-leukemic, anti-lung, and anti-breast cancer properties. The aim of the present investigation was to study the interactive potentials of DAPG with the metastatic proteins such as MMP-2, MMP-9, and NF-κB and antiapoptotic Bcl-2 family proteins such as Bcl-2, Bcl-w, and Bcl-xL through in silico interaction and in vitro studies. The in silico modeling predicted high interactions of DAPG with the metastatic proteins, especially MMP-2, MMP-9, and NF-κB with the glide score of -7.028, -6.304, and -5.231, respectively. Similarly, the DAPG had weak interactions with the antiapoptotic Bcl-2, Bcl-w, and Bcl-xL with the glide score of -4.505, -3.839, and -4.003, respectively. The interaction studies further revealed the inhibition of MMP-2, MMP-9, and NF-κB activities with the low IC50 concentration of 5.82 ± 1.6, 6.74 ± 1.2, and 10.7 ± 1.5 µM respectively, in the presence of DAPG. Similarly, DAPG inhibited the Bcl-2, Bcl-xL and Bcl-w activities with the high IC50 concentration of 29.8 ± 1.9, 85.9 ± 2.7, and 97.4 ± 1.5 µM, respectively. These results correlate with the relatively high IC50 concentration of 16.3 ± 1.76, 7.67 ± 0.78, and 10.7 ± 0.96 µM in the Bcl-2-overexpressing HL-60, K562 and Raji leukemic cells than the metastatic A549 and MDA MB-231 cancer cells with the low IC50 concentration of 0.06 ± 0.02 and 0.08 ± 0.01 µM, respectively, compared to the healthy, human embryonic kidney (HEK-293) cells with the high IC50 concentration of 54.7 ± 1.43 µM. In summary, the affinity of DAPG with proteins are in the order of MMP-2 > MMP-9 > NF-κB > Bcl-2 > Bcl-xL > Bcl-w. Results presented in this study confirmed the high interaction of DAPG with the metastatic proteins than the antiapoptotic Bcl-2 family proteins.

Phenazine-1-carboxamide (PCN) from Pseudomonas sp. strain PUP6 selectively induced apoptosis in lung (A549) and breast (MDA MB-231) cancer cells by inhibition of antiapoptotic Bcl-2 family proteins.

Phenazine-1-carboxamide (PCN), a naturally occurring simple phenazine derivative isolated from Pseudomonas sp. strain PUP6, exhibited selective cytotoxic activity against lung (A549) and breast (MDA-MB-231) cancer cell lines in differential and dose-dependent manner compared to normal peripheral blood mononuclear cells. PCN-treated cancer cells showed the induction of apoptosis as evidenced by the release of low level of LDH, morphological characteristics, production of reactive oxygen species, loss of mitochondrial membrane potential (ΔΨm) and induction of caspase-3. At molecular level, PCN instigates apoptosis by mitochondrial intrinsic apoptotic pathway via the overexpression of p53, Bax, cytochrome C release and activation of caspase-3 with the inhibition of oncogenic anti-apoptotic proteins such as PARP and Bcl-2 family proteins (Bcl-2, Bcl-w and Bcl-xL). The in silico docking studies of PCN targeted against the anti-apoptotic members of Bcl-2 family proteins revealed the interaction of PCN with the BH3 domain, which might lead to the induction of apoptosis due to the inhibition of antiapoptotic proteins. Due to its innate inhibition potential of antiapoptotic Bcl-2 family proteins, PCN may be used as potent anticancer agent against both lung and breast cancer.

Functional Characterization of Thyroid Peroxidase Missense Variants Causing Thyroid Dyshormonogenesis in Asian Indian Population.

INTRODUCTION: Thyroid dyshormonogenesis (TDH) is a subgroup of congenital hypothyroidism with recessive inheritance resulting from disease-causing variants in thyroid hormone biosynthesis pathway genes, like DUOX2, TG, TPO, SLC5A5, SLC26A4, IYD, DUOXA2, and SLC26A7. Thyroid peroxidase (TPO) is a crucial enzyme involved in thyroid hormone biosynthesis and is one of the frequently mutated genes in patients with TDH. The purpose of the study was to describe the in silico and functional characterization of novel variants in TPO gene identified in patients with TDH. METHODS: We performed exome sequencing in Indian patients with TDH. In the current study, we describe the results of patients with TPO gene mutations. Exome sequencing results were further analysed by Sanger sequencing, computational studies, and in vitro functional studies such as immunofluorescence and enzyme assay. RESULTS: We identified nine biallelic disease-causing variants in the TPO gene in 12 patients from nine unrelated Indian families. Eight of the nine variants were novel. No recurrent variants were identified. Computational analysis of six missense variants showed that these amino acid substitutions caused changes in non-covalent interactions with the adjacent residues that may affect the TPO protein structure and function. In vitro experimental data using immunofluorescence assay showed that these variants did not affect the plasma membrane localization of the TPO protein but caused a significant loss of TPO enzymatic activity compared to the wild type. CONCLUSION: Our study revealed multiple novel pathogenic variants in TPO gene in Indian patients, thereby expanding the genotype spectrum. Functional studies helped us to reveal the pathogenicity of the missense variants.

5-Methyl phenazine-1-carboxylic acid: a novel bioactive metabolite by a rhizosphere soil bacterium that exhibits potent antimicrobial and anticancer activities.

A new rhizosphere soil bacterium that exhibits antimicrobial potential against human pathogens was isolated. On the basis of 16S ribosomal RNA nucleotide sequence homology and subsequent phylogenetic tree analysis, the strain PUW5 was identified as Pseudomonas putida. A bioactive metabolite was extracted and purified using silica gel column chromatography and preparative HPLC. Characterization of metabolite was done by employing Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and mass spectroscopy (MS). On the basis of spectroscopic data, the metabolite was structurally elucidated as 5-methyl phenazine-1-carboxylic acid betaine (MPCAB). The MPCAB exhibits selective cytotoxicity towards lung (A549) and breast (MDA MB-231) cancer cell lines in dose-dependent manner with IC50 value of 488.7±2.52 nM and 458.6±2.48 nM respectively. The MPCAB exhibited inhibition of cell viability, DNA synthesis, induced G1 cell cycle arrest and apoptosis in cancer cells. The docking and interaction studies confirmed the binding potential of MPCAB with Bcl-2 than Bcl-xL and Bcl-w proteins. These results strongly suggest that the MPCAB induces apoptosis in A549 and MDA MB-231 cancer cells through mitochondrial intrinsic pathway via activation of caspase-3 and down regulation of Bcl-2 protein.