Culture filtrate ether extracted metabolites from Streptomyces levis ABRIINW111 increased apoptosis and reduced proliferation in acute lymphoblastic leukemia

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.

Bioactive Potential of Several Actinobacteria Isolated from Microbiologically Barely Explored Desert Habitat, Saudi Arabia

Simple Summary

Bioactive natural products have been regarded as promising tools for treatment of various ailments. Among natural sources, actinomycetes have been widely explored for their potential bioactivity. In this regard, the present study has focused on the phytochemical content and biological activities of several actinobacteria isolates, which were investigated for their phenolic and flavonoid content, as well as their antioxidant, antibacterial and antiprotozoal activities. The most active isolates were further investigated for their antileukemic activity, where such isolates were shown to exert cytotoxic activity against the tested cell lines, following a mechanism that might be due to the ability of the active isolate extracts to reduce cyclooxygenase and lipoxygenase activities. Overall, isolation and characterization of the active molecule from the potential actinomycetes strains will pave the way for the development of drugs against human diseases such as blood cancer.

Abstract

Biomolecules from natural sources, including microbes, have been the basis of treatment of human diseases since the ancient times. Therefore, this study aimed to investigate the potential bioactivity of several actinobacteria isolates form Al-Jouf Desert, Saudi Arabia. Twenty-one actinobacterial isolates were tested for their antioxidant (flavonoids, phenolics, tocopherols and carotenoids) content, and biological activities, namely FRAP, DPPH, ABTS, SOS and XO inhibition, anti-hemolytic and anti-lipid peroxidation as well as their antibacterial and antiprotozoal activities. Accordingly, five isolates (i.e., Act 2, 12, 15, 19 and 21) were selected and their 90% ethanolic extracts were used. The phylogenetic analysis of the 16S rRNA sequences indicated that the most active isolates belong to genus Streptomyces. The genus Streptomyces has been documented as a prolific producer of biologically active secondary metabolites against different cancer types. Thus, the anti-blood cancer activity and the possible molecular mechanisms by which several Streptomyces species extracts inhibited the growth of different leukemia cells, i.e., HL-60, K562 and THP-1, were investigated. In general, the five active isolates showed cytotoxic activity against the tested cell lines in a dose dependent manner. Among the potent isolates, isolate Act 12 significantly decreased the cell viability and showed maximum cytotoxic activities against both HL-60 and K562 cells, while isolate Act 15 exhibited maximum cytotoxic activity against THP-1 cells. Moreover, Act 2 and Act 12 reduced cyclooxygenase (COX-2) and lipoxygenase (LOX) activity, which is involved in the proliferation and differentiation of cancer cells and may represent a possible molecular mechanism underlying leukemia growth inhibition. The bioactive antioxidant extracts of the selected Streptomyces species inhibited leukemia cell growth by reducing the COX-2 and LOX activity. Overall, our study not only introduced a promising natural alternative source for anticancer agents, but it also sheds light on the mechanism underlying the anticancer activity of isolated actinomycetes.

Therapeutic applications and biological activities of bacterial bioactive extracts

Bacteria are rich in a wide variety of secondary metabolites, such as pigments, alkaloids, antibiotics, and others. These bioactive microbial products serve a great application in human and animal health. Their molecular diversity allows these natural products to possess several therapeutic attributes and biological functions. That's why the current natural drug industry focuses on uncovering all the possible ailments and diseases that could be combated by bacterial extracts and their secondary metabolites. In this paper, we review the major utilizations of bacterial natural products for the treatment of cancer, inflammatory diseases, allergies, autoimmune diseases, infections and other diseases that threaten public health. We also elaborate on the identified biological activities of bacterial secondary metabolites including antibacterial, antifungal, antiviral and antioxidant activities all of which are essential nowadays with the emergence of drug-resistant microbial pathogens. Throughout this review, we discuss the possible mechanisms of actions in which bacterial-derived biologically active molecular entities could possess healing properties to inspire the development of new therapeutic agents in academia and industry.

Mesenchymal Stem Cells Could Be Considered as a Candidate for Further Studies in Cell-Based Therapy of Alzheimer's Disease via Targeting the Signaling Pathways

Mesenchymal stem cells (MSCs) are of particular interest because of their potential in regenerative medicine. Stem cell-based therapies cast a new hope for neurodegenerative disease treatment as a regeneration strategy, including treatment for Alzheimer's disease (AD). A multitude of cytokines and factors secreted from MSCs are known to give such multifunctional properties, but associated mechanisms of these factors have yet to be entirely understood. To better understand the in vitro effect of MSCs on a neurodegenerative disorder, we treated primary cortical and hippocampal neural cells with amyloid β (Aβ) as an in vitro cell line model for AD. For this purpose, bone marrow-derived MSCs (BMSCs) were cocultured with Aβ-treated neural cells, collected at day 3, and subjected to absolute telomere length measurement and telomerase activity assay. Next, the gene and protein expression levels of mTOR, p-mTOR, AMPK, p-AMPK, GSK-3β, p-GSK-3β, Wnt3, and β-catenin were investigated. Also, after 3 days of coculture treatment, the supernatant was collected from both groups for cytokine measurement. It was found that telomere length as a biomarker in neurodegenerative disorder as well as telomerase activity had significantly increased in the experimental group, and the presence of IL-6, IL-10, and TGF-β was obviously significant in the cocultured media. Also, BMSCs significantly changed the gene and protein expression of mTOR, AMPK, GSK-3β, and Wnt3/β-catenin signaling pathways components. It was concluded that the mentioned effects of MSCs on neural cells as an in vitro cell line model for AD as a therapeutic agent can be related to the signaling network.

Interleukin-6, -8, and TGF-β Secreted from Mesenchymal Stem Cells Show Functional Role in Reduction of Telomerase Activity of Leukemia Cell Via Wnt5a/β-Catenin and P53 Pathways

Purpose: The effect of mesenchymal stem cells (MSCs) on the immortality features of malignant cells, such as hematologic cancerous cells, are controversial, and the associated mechanisms are yet to be well understood. The aim of the present study was to investigate the in vitro effect of bone marrow-derived MSCs (BMSCs) on the chronic myeloid leukemia cell line K562 through telomere length measurements, telomerase activity assessments, and hTERT gene expression. The possible signaling pathways involved in this process, including Wnt-5a/β-catenin and P53, were also evaluated.

Methods: Two cell populations (BMSCs and K562 cell line) were co-cultured on transwell plates for 7 days. Next, K562 cells were collected and subjected to quantitative real-time PCR, PCR-ELISA TRAP assay, and the ELISA sandwich technique for telomere length, hTERT gene expression, telomerase activity assay, and cytokine measurement, respectively. Also, the involvement of the mentioned signaling pathways in this process was reported by real-time PCR and Western blotting through gene and protein expression, respectively.

Results: The results showed that BMSCs caused significant decreases in telomere length, telomerase activity, and the mRNA level of hTERT as a regulator of telomerase activity. The significant presence of interleukin (IL)-6, IL-8, and transforming growth factor beta (TGF-β) was obvious in the co-cultured media. Also, BMSCs significantly decreased and increased the gene and protein expression of β-catenin and P53, respectively.

Conclusion: It was concluded that the mentioned effects of IL-6, IL-8, and TGF-β cytokines secreted from MSCs on K562 cells as therapeutic agents were applied by Wnt-5a/β-catenin and P53 pathways

Neoantimycin F, a Streptomyces-Derived Natural Product Induces Mitochondria-Related Apoptotic Death in Human Non-Small Cell Lung Cancer Cells

Streptomyces-derived natural products have been become a major focus of anti-tumor drug discovery studies. Neoantimycin F (NAT-F), was isolated from Streptomyces conglobatus by our group. Here, we examined the anti-cancer activities and its underlying molecular mechanisms implicated in NAT-F-induced apoptosis of non-small cell lung cancer (NSCLC) cells. Our results showed that NAT-F exerted excellent growth-inhibitory activity against PC9 and H1299 cells in a concentration-dependent manner. NAT-F-induced cell cycle arrest at S and G₀/G₁ phase in PC9 and H1299 cells, respectively. Further investigation revealed that the key proteins (including cyclinD1, cyclinE1, cyclinB1, CDK2, and CDK4) were involved in the cell regulation by NAT-F. Additionally, NAT-F significantly increased the production of reactive oxygen species (ROS), induced DNA damage, nuclear condensation, and cell apoptosis in both cell lines. Moreover, loss of the mitochondrial membrane potential (MMP) was markedly induced by NAT-F. Additional results revealed that NAT-F could up-regulate pro-apoptotic protein Bax and down-regulate anti-apoptotic protein Bcl-2, Mcl-1, and Bcl-x_L, resulting in cytochrome c release from mitochondria and sequential activation of caspase-9 and -3, as well as the cleavage of poly (ADP-ribose) polymerase. Meanwhile, c-Jun N-terminal kinase (JNK), p38 MAPK (p38), and extracellular signal-regulated kinase (ERK) signaling pathway were also involved in anti-cancer activity of NAT-F in NSCLC cells. Taken together, these findings indicated that NAT-F possessed anti-proliferative effect and induced apoptosis in NSCLC cells in vitro and may be conducive to promote the development of novel anti-NSCLC agents.

Cytokines secreted from bone marrow derived mesenchymal stem cells promote apoptosis and change cell cycle distribution of K562 cell line as clinical agent in cell transplantation

Mesenchymal stem cells (MSCs) are of special interest due their potential clinical use in cell-based therapy. Therapies engaging MSCs are showing increasing promise in the cancer treatment and anticancer drug screening applications. A multitude of growth factors and cytokines secreted from these cells are known to give such multifunctional properties, but details of their role are yet to be absolutely demonstrated. In this study, we have evaluated the influence of BMSCs on K562 cell line as chronic myeloid leukemia (CML) cells, with the use of a cytokine antibody array recognizing 34 cytokines. For this purpose, BMSCs were isolated and co-cultured with K562 cells; thereafter, cultured K562 alone and co-cultured K562 with BMSCs (10:1) were collected at day 7 and subjected to cell cycle distribution assay as well as annexin/PI analysis and Ki/caspase-3 assay for apoptosis assessment. In the following, the gene and protein expression levels of BAX and BCL-2 as pro- and anti-apoptotic agents were investigated. Furthermore, after 7 days' treatment, culture medium was collected from both control and experimental groups for cytokine antibody array. It was found that BMSCs resulted in a robust increase in the number of cells at G0/G1 phase and arrest the G0/G1 phase as well as significantly inducing late apoptosis in K562 cells. The significant presence of TIMP-1 (tissue inhibitor of metalloproteinases-1), and moderate elevated signals for CINC-1 (cytokine-induced neutrophil chemoattractant-1) were obvious in the co-cultured conditioned media, but no significant increase was found in 32 other cytokines. It is concluded that co-culture of BMSCs with K562 cells could secrete a substantial amount of TIMP-1 and CINC-1. These cytokines could be involved in the inhibition of the K562 cell proliferation via BAX and caspase-3 cascade pathways.