Induction of apoptosis and cell cycle arrest in colorectal cancer cells by novel anticancer metabolites of Streptomyces sp. 801

Identification of bio-active secondary metabolites from Actinobacteria as potential drug targets against Porphyromonas gingivalis in oral squamous cell carcinoma using molecular docking and dynamics study

Chronic periodontitis caused by the bacteria Porphyromonas gingivalis is thought to be a risk factor for the advancement of oral squamous cell carcinoma (OSCC). Virulence factors of P. gingivalis include gingipains, outer membrane surface lipoproteins, and fimbriae contribute to the activation of oncogenic pathways in OSCC by up-regulating different cytokines. Gingipains (Arg and Lys) proteases have an important role in the activation of proMMP-9, which promotes cellular invasion and metastatic ability of OSCC. Thus gingipains and MMP-9 were actively investigated as potential therapeutic targets in OSCC therapy. Various natural bioactive compounds from Actinobacteria have been explored for their anticancer potential in a variety of cancers, but very few studies have been reported in OSCC. Therefore, the current study is focused to identify potential actinobacterial compounds that can be considered as a therapeutic target against gingipains and inflammatory proteins in OSCC through high-throughput virtual screening, Molecular Docking (MD), and Molecular Dynamics Simulation (MDS) approaches. A total of 179 bioactive secondary metabolites of Actinobacteria were explored for their binding affinity against six virulence proteins of P. gingivalis. The Molecular Docking studies revealed that among 179 metabolites screened, Actinosporin G showed a highly acceptable binding affinity of -7.9 kcal/mol with RgpB (1CVR), and exhibited multi-protein targeting and drug-likeness property and passed level of toxicity. Comprehensive docking interaction of the best top-ranked Actinosporin G with OSCC-related protein targets illustrated high binding affinity towards MMP-9 and JAK-1 proteins among all targeted receptor proteins. The molecular dynamic (MD) simulation has been executed for the metabolite Actinosporin G for both bacterial gingipain (RgpB) and MMP-9 & JAK-1 showed stable intermolecular binding with both hydrogen and hydrophobic interactions. In conclusion, this work suggests that the bioactive secondary metabolite of Actinosporin G from Actinobacteria genera may serve as a promising therapy for P. gingivalis-induced OSCC.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s40203-024-00209-0.

Synergistic Anti-Cancer Effects of ERB-041 and Genistein through Estrogen Receptor Suppression-Mediated PI3K/AKT Pathway Downregulation in Canine Mammary Gland Tumor Cells

Canine-mammary-gland tumors (CMTs) are prevalent in female dogs, with approximately 50% of them being malignant and often presenting as inoperable owing to their size or metastasis. Owing to poor outcomes, effective alternatives to conventional chemotherapy for humans are necessary. Two estrogen receptors, estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ), which act in opposition to each other, are involved, and CMT growth involves ERα through the phosphoinositide 3-kinases (PI3K)/AKT pathway. In this study, we aimed to identify the synergistic anti-cancer effects of ERB-041, an ERβ agonist, and genistein, an isoflavonoid from soybeans known to have ERβ-specific pseudo-estrogenic actions, on CMT-U27 and CF41.Mg CMT cell lines. ERB-041 and genistein synergistically inhibited cell proliferation and increased the number of annexin V-positive cells in both cell lines. Furthermore, we observed a synergistic increase in the Bax/Bcl-2 ratio and cleaved caspase-3 expression. Additionally, cell-cycle arrest occurred through the synergistic regulation of cyclin D1 and cyclin-dependent kinase 4 (CDK4). We also found a synergistic decrease in the expression of ERα, and the expression of proteins involved in the PI3K/AKT pathway, including p-PI3K, phosphatase and tensin homolog (PTEN), AKT, and mechanistic target of rapamycin (mTOR). In conclusion, ERB-041 and genistein exhibited a synergistic anticancer effect on CMTs, suggesting that cotreatment with ERB-041 and genistein is a promising treatment for CMTs.

Redefining bioactive small molecules from microbial metabolites as revolutionary anticancer agents

Cancer treatment remains a significant challenge due to issues such as acquired resistance to conventional therapies and the occurrence of adverse treatment-related toxicities. In recent years, researchers have turned their attention to the microbial world in search of novel and effective drugs to combat this devastating disease. Microbial derived secondary metabolites have proven to be a valuable source of biologically active compounds, which exhibit diverse functions and have demonstrated potential as treatments for various human diseases. The exploration of these compounds has provided valuable insights into their mechanisms of action against cancer cells. In-depth studies have been conducted on clinically established microbial metabolites, unraveling their anticancer properties, and shedding light on their therapeutic potential. This review aims to comprehensively examine the anticancer mechanisms of these established microbial metabolites. Additionally, it highlights the emerging therapies derived from these metabolites, offering a glimpse into the immense potential they hold for anticancer drug discovery. Furthermore, this review delves into approved treatments and major drug candidates currently undergoing clinical trials, focusing on specific molecular targets. It also addresses the challenges and issues encountered in the field of anticancer drug research and development. It also presents a comprehensive exposition of the contemporary panorama concerning microbial metabolites serving as a reservoir for anticancer agents, thereby illuminating their auspicious prospects and the prospect of forthcoming strides in the domain of cancer therapeutics.

In vitro cytotoxic investigation of some synthesized 1,6-disubstituted-1-azacoumarin derivatives as anticancer agents

Aims: In this study, novel synthesized 1,6-disubstituted-1-azacoumarin-3-carboxylic acid derivatives were designed, synthesized and evaluated as potential anticancer agents. Materials & methods: The cytotoxicity of novel 1-azacoumarin-3-carboxylic acid derivatives was tested using an MTT assay. High potency was shown by DNA flow cytometry on MCF-7 cells for compound 3b. In addition, topoisomerase IIβ, caspase 3/7, Bax and Bcl-2 enzymes were used to study apoptotic activity. In the same studies, molecular docking analysis assessed activity. Results & conclusion: Cytotoxicity screening identified multiple bioactive compounds, especially compound 3b. Analysis of DNA flow cytometry revealed that compound 3b exhibited cell cycle arrest. Compound 3b had an increase in the expression of Bax/Bcl-2 ratio and caspase 3/7, and a decrease in topoisomerase IIβ enzyme inhibition.

Resistomycin Suppresses Prostate Cancer Cell Growth by Instigating Oxidative Stress, Mitochondrial Apoptosis, and Cell Cycle Arrest

Globally, prostate cancer is among the most threatening and leading causes of death in men. This study, therefore, aimed to search for an ideal antitumor strategy with high efficacy, low drug resistance, and no or few adverse effects. Resistomycin is a natural antibiotic derived from marine actinomycetes, and it possesses various biological activities. Prostate cancer cells (PC3) were treated with resistomycin (IC12.5: 0.65 or IC25: 1.3 µg/mL) or 5-fluorouracil (5-FU; IC25: 7 µg/mL) for 24 h. MTT assay and flow cytometry were utilized to assess cell viability and apoptosis. Oxidative stress, apoptotic-related markers, and cell cycle were also assessed. The results revealed that the IC50 of resistomycin and 5-FU on PC3 cells were 2.63 µg/mL and 14.44 µg/mL, respectively. Furthermore, treated cells with the high dose of resistomycin showed an increased number of apoptotic cells compared to those treated with the lower dose. Remarkable induction of reactive oxygen species generation and lactate dehydrogenase (LDH) leakage with high malondialdehyde (MDA), carbonyl protein (CP), and 8-hydroxyguanosine (8-OHdG) contents were observed in resistomycin-treated cells. In addition, marked declines in glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) in PC3 cells subjected to resistomycin therapy were observed. Resistomycin triggered observable cell apoptosis by increasing Bax, caspase-3, and cytosolic cytochrome c levels and decreasing Bcl-2 levels. In addition, notable downregulation of proliferating cell nuclear antigen (PCNA) and cyclin D1 was observed in resistomycin-treated cancerous cells. According to this evaluation, the antitumor potential of resistomycin, in a concentration-dependent manner, in prostate cancer cells was achieved by triggering oxidative stress, mitochondrial apoptosis, and cell cycle arrest in cancer cells. In conclusion, our investigation suggests that resistomycin can be considered a starting point for developing new chemotherapeutic agents for human prostate cancer.

Identification of the Biosynthetic Gene Cluster of New Piperazic Acid-Containing Lipopeptides with Cytotoxic Activity in the Genome of Marine Streptomyces PHM034

Three novel lipopeptides, PM130391 (1), PM130392 (2), and PM140293 (3) were obtained from cultures of Streptomyces tuirus PHM034 isolated from a marine sediment. Structural elucidation of the three compounds showed they belong to the nonribosomal peptides family, and they all contain an acylated alanine, three piperazic acids, a methylated glycine, and an N-hydroxylated alanine. The difference between the three compounds resides in the acyl chain bound to the alanine residue. All three compounds showed cytotoxic activity against human cancer cell lines. Genome sequence and bioinformatics analysis allowed the identification of the gene cluster responsible for the biosynthesis. Inactivation of a nonribosomal peptide synthase of this cluster abolished the biosynthesis of the three compounds, thus demonstrating the involvement of this cluster in the biosynthesis of these lipopeptides.

Streptomyces Bioactive Metabolites Prevent Liver Cancer through Apoptosis, Inhibiting Oxidative Stress and Inflammatory Markers in Diethylnitrosamine-Induced Hepatocellular Carcinoma

A safe and effective treatment for liver cancer is still elusive despite all attempts. Biomolecules produced from natural products and their derivatives are potential sources of new anticancer medications. This study aimed to investigate the anticancer potential of a Streptomyces sp. bacterial extract against diethylnitrosamine (DEN)-induced liver cancer in Swiss albino mice and explore the underlying cellular and molecular mechanisms. The ethyl acetate extract of a Streptomyces sp. was screened for its potential anticancer activities against HepG-2 using the MTT assay, and the IC₅₀ was also determined. Gas chromatography-mass spectrometric analysis was used to identify the chemical constituents of the Streptomyces extract. Mice were administered DEN at the age of 2 weeks, and from week 32 until week 36 (4 weeks), they received two doses of Streptomyces extract (25 and 50 mg/kg body weight) orally daily. The Streptomyces extract contains 29 different compounds, according to the GC-MS analysis. The rate of HepG-2 growth was dramatically reduced by the Streptomyces extract. In the mice model. Streptomyces extract considerably lessened the negative effects of DEN on liver functions at both doses. Alpha-fetoprotein (AFP) levels were significantly (p < 0.001) decreased, and P53 mRNA expression was increased, both of which were signs that Streptomyces extract was suppressing carcinogenesis. This anticancer effect was also supported by histological analysis. Streptomyces extract therapy additionally stopped DEN-induced alterations in hepatic oxidative stress and enhanced antioxidant activity. Additionally, Streptomyces extract reduced DEN-induced inflammation, as shown by the decline in interleukin-1 beta (IL-1β) and tumor necrosis factor-alpha (TNF-α) levels. Additionally, the Streptomyces extract administration dramatically boosted Bax and caspase-3 levels while decreasing Bcl-2 expressions in the liver according to the Immunohistochemistry examination. In summary, Streptomyces extract is reported here as a potent chemopreventive agent against hepatocellular carcinoma through multiple mechanisms, including inhibiting oxidative stress, cell apoptosis, and inflammation.