In vitro and in silico anticancer potential analysis of Streptomyces sp. extract against human lung cancer cell line, A549

Independent antioxidant and anticancer properties of a novel thermostable lysozyme isolated from Bacillus paralicheniformis: in silico and in vitro studies

In this study, we evaluated the independent anticancer properties of a novel heat-stable lysozyme derived from the thermophilic bacterium Bacillus paralicheniformis (BplzC) to identify potential alternative therapies to address the suboptimal outcomes of current cancer treatments. Using the String 10.5 database, an in-silico protein-protein interaction study predicted that BplzC was a strong functional partner of cytochrome c, indicating a potential role in cancer cell apoptosis. Further, the HDOCK server predicted that BplzC strongly bound to cell death receptors, such as cytokines FAS receptor, leading to activation of cytochrome c and subsequent apoptosis in the cancer cell line. In vitro assays demonstrated uniform apoptotic activity of BplzC against various cancer cell lines, while showing no apoptotic activity against normal non-cancer cell lines. And showing no apoptotic activity against normal non-cancer cell lines suggested a very specific mode of action and without any adverse side effects. Additionally, BplzC exhibited ROS scavenging activity and reducing ability comparable to ascorbic acid, and significantly accelerated HEK293 cell migration. Our findings suggest that BplzC has specific cytotoxic effects on cancer cells and may be a valuable natural source of antioxidants for future use in the nutritional and pharmaceutical sectors.

8-Hydroxyquinoline a natural chelating agent from Streptomyces spp. inhibits A549 lung cancer cell lines via BCL2/STAT3 regulating pathways

Biomolecules from Streptomyces spp. are emerging sources of natural drugs and have been focused on over the decade. The discovery of bioactive chemotherapeutic molecules from soil Streptomyces spp. has opened the medium for the search for natural drugs. In the current study, 8-HOQ was extracted and purified from soil Streptomyces spp. and was evaluated on A549 and BEAS cell lines. The apoptotic and caspase mediated pathways were evaluated using cell proliferation, dual fluorescent staining, migration, invasion and mRNA as well as protein quantification of apoptotic markers. In vitro cytotoxicity test revealed that 8-HOQ possesses potent cytotoxicity activities with IC₅₀ values of 26 µM, 5 µM, 7.2 µM at 24 h, 48 h, and 72 h respectively against A549 lung cancer cell lines. The result also demonstrated that 8-HOQ from Streptomyces spp significantly inhibited the A549 lung cancer cell lines and activated the intrinsic pathways of apoptosis. The caspase-3 and caspase-8 activities were potentially elevated in 8-HOQ treated A549 cell lines and confirmed that 8-HOQ mediated A549 cancer cell death through the intrinsic pathway. The results explored caspase-mediated apoptosis as a mechanism underlying the inhibition of cancer cell viability in a dose-dependent manner. The expression of P53, BCL2 and STAT3 were inhibited in A549 cell lines and confirmed the metastasis inhibitory potential of 8-HOQ by blocking migration and invasion in A549 cell lines. These results indicated that 8-HOQ from Streptomyces spp. potentially inhibited growth and migration of A549 lung cancer cell lines.

A swamp forest Streptomyces sp. strain KF15 with broad spectrum antifungal activity against chilli pathogens exhibits anticancer activity on HeLa cells

During the investigation, soil actinomycetes were isolated from Kathlekanu swamp forest and the crude ethyl acetate extract from the potent isolate KF15 was analysed with GC-MS and HPTLC to identify bioactive metabolites. The crude extract was examined for in-vitro antifungal activity on pathogens of chilli; MTT cytotoxicity assay was performed against HeLa cell line to determine the anticancer potential. The isolate Streptomyces sp. strain KF15 exhibited antagonistic activity against fungal pathogens by inhibiting growth and altering growth pattern with increased antimicrobial activity in dose-dependent manner. GC-MS revealed many bioactive compounds and HPTLC depicted metabolite fingerprint. The IC₅₀ of 99.85 µg/ml indicated the high potential of KF15 extract to prevent proliferation of HeLa cells. Therefore, the findings of this study indicate that the crude extract from Streptomyces sp. strain KF15 contains antifungal and anticancer metabolites; further study on purification could help in controlling many fungal diseases as well as cervical cancer in humans.