Selective Induction of Apoptosis by Azadarichta indica Leaf Extract by Targeting Oxidative Vulnerabilities in Human Cancer Cells

Natural products and mitochondrial allies in colorectal cancer therapy

Colorectal cancer (CRC) is a globally prevalent malignancy with a high potential for metastasis. Existing cancer treatments have limitations, including drug resistance and adverse effects. Researchers are striving to develop effective therapies to address these challenges. Impressively, contemporary research has discovered that many natural products derived from foods, plants, insects, and marine invertebrates can suppress the progression, metastasis, and invasion of CRC. In this review, we conducted a comprehensive search of the CNKI, PubMed, Embase, and Web of Science databases from inception to April 2023 to evaluate the efficacy of natural products targeting mitochondria to fight against CRC. Mitochondria are intracellular energy factories involved in cell differentiation, signal transduction, cell cycle regulation, apoptosis, and tumorigenesis. The identified natural products have been classified and summarized based on their mechanisms of action. These findings indicate that natural products can induce apoptosis in colorectal cancer cells by inhibiting the mitochondrial respiratory chain, ROS elevation, disruption of mitochondrial membrane potential, the release of pro-apoptotic factors, modulation of the Bcl-2 protein family to facilitate cytochrome c release, induction of apoptotic vesicle activity by activating the caspase protein family, and selective targeting of mitochondrial division. Furthermore, diverse apoptotic signaling pathways targeting mitochondria, such as the MAPK, p53, STAT3, JNK and AKT pathway, have been triggered by natural products. Natural products such as diosgenin, allopurinol, and clausenidin have demonstrated low toxicity, high efficacy, and multi-targeted properties. Mitochondria-targeting natural products have great potential for overcoming the challenges of CRC therapy.

Transient receptor potential channel stimulation induced oxidative stress and apoptosis in the colon of mice with colitis-associated colon cancer: modulator role of Sambucus ebulus L

BACKGROUND

Increased Ca²⁺ entry causes an increase in tumor cell proliferation, apoptosis, cytosolic reactive free oxygen species (cyROS), and mitochondrial ROS (miROS) in tumor cells. The cyROS and miROS stimulate the cation channels, including the TRPA1, TRPM2, and TRPV1. Sambucus ebulus L (SEB) (Dwarf Elder) induced both antioxidant and anticancer effects in the human hepatocarcinoma and human colon carcinoma cancer cell lines. We investigated the etiology of colorectal cancer and the impact of three channels, as well as the protective effects of SEB on apoptosis, cyROS, and miROS in the colon of mice with colitis-associated colon cancer (AOM/DSS).

METHODS

A total 28 mice were equally divided into four groups as control, SEB (100 mg/kg/day for 14 days), AOM/DSS, and SEB + AOM/DSS. Azoxymethane/dextran sulfate sodium-induced colon cancer associated with colitis was induced in the AOM/DSS groups within 10 weeks. At the end of the experiments, the colon samples were removed from the mice.

RESULTS

The protein bands of caspase - 3, TRPA1, TRPM2, and TRPV1 were increased by the treatments of AOM/DSS. The levels of apoptosis, cyROS, cleaved caspase - 3, and cleaved caspase - 9, as well as the depolarization of the mitochondrial membrane, all increased in the AOM/DSS group. Although they were reduced in the SEB and AOM/DSS + SEB groups by the treatments of SEB, TRPA1 (AP18), TRPM2 (ACA), and TRPV1 (capsazepine) antagonists, the apoptotic and oxidant values were further elevated in the AOM/DSS group by the treatments of TRPA1 (cinnamaldehyde), TRPM2 (H₂O₂), and TRPV1 (capsaicin) agonists.

CONCLUSION

The activations of TRPA1, TRPM2, and TRPV1 channels induced the increase of apoptotic and oxidant actions in the colon cancer cells, although their inhibition via SEB treatment decreased the actions. Hence, TRPA1, TRPM2, and TRPV1 activations could be used as effective agents in the treatment of colon tumors.

Hypomyelinating Leukodystrophy 10 (HLD10)-Associated Mutations of PYCR2 Form Large Size Mitochondria, Inhibiting Oligodendroglial Cell Morphological Differentiation

Hypomyelinating leukodystrophy 10 (HLD10) is an autosomal recessive disease related to myelin sheaths in the central nervous system (CNS). In the CNS, myelin sheaths are derived from differentiated plasma membranes of oligodendrocytes (oligodendroglial cells) and surround neuronal axons to achieve neuronal functions. Nucleotide mutations of the pyrroline-5-carboxylate reductase 2 (PYCR2) gene are associated with HLD10, likely due to PYCR2's loss-of-function. PYCR2 is a mitochondrial residential protein and catalyzes pyrroline-5-carboxylate to an amino acid proline. Here, we describe how each of the HLD10-associated missense mutations, Arg119-to-Cys [R119C] and Arg251-to-Cys [R251C], lead to forming large size mitochondria in the FBD-102b cell line, which is used as an oligodendroglial cell differentiation model. In contrast, the wild type proteins did not participate in the formation of large size mitochondria. Expression of each of the mutated R119C and R251C proteins in cells increased the fusion abilities in mitochondria and decreased their fission abilities relatively. The respective mutant proteins, but not wild type proteins also decreased the activities of mitochondria. While cells expressing the wild type proteins exhibited differentiated phenotypes with widespread membranes and increased expression levels of differentiation marker proteins following the induction of differentiation, cells harboring each of the mutant proteins did not. Taken together, these results indicate that an HLD10-associated PYCR2 mutation leads to the formation of large mitochondria with decreased activities, inhibiting oligodendroglial cell morphological differentiation. These results may reveal some of the pathological mechanisms in oligodendroglial cells underlying HLD10 at the molecular and cellular levels.

Acacia catechu seed extract provokes cytotoxicity via apoptosis by intrinsic pathway in HepG2 cells

Acacia catechu Willd (Fabaceae) is a thorny tree widely distributed in India and commonly used as traditional Ayurvedic medicine for various ailments. The current study evaluates the cytotoxic potentials of A. catechu ethanolic seed extract (ACSE) in HepG2 cells, a human hepatocellular carcinoma cell line. The HepG2 cells were treated with 0.1, 0.3, 1, 3, 10, 30, 100, 300 and 1000 μg/ml of ACSE and the cytotoxic effect was evaluated by MTT and lactate dehydrogenase (LDH) leakage assays. The IC₅₀ of ACSE was found at 77.04 μg/ml and therefore, further studies were carried out with the concentrations of 35 and 70 μg/ml. The intracellular reactive oxygen species (ROS) generation and apoptosis-related morphological changes were evaluated. Gene expressions of Bax, Bcl-2, cytochrome C (Cyt-c), caspases-9 and 3 were analyzed by qPCR. The ACSE treatments caused LDH leakage was associated with an increased ROS generation. The increased ROS generation was associated with the downregulation of intracellular antioxidant enzyme superoxide dismutase and reduced glutathione content. AO/EB and PI staining also confirmed chromatin condensation and apoptosis. The flow cytometric analysis showed an accumulation of HepG2 cells at sub G0/G1 (apoptotic) phase upon ACSE treatments. The ACSE induced cytotoxicity and oxidative stress were related to increased apoptotic marker gene expressions such as Bax, Cyt-c, caspase-9 and 3, and decreased anti-apoptotic marker Bcl-2. The current finding suggests that ACSE has apoptosis-inducing potential via the mitochondrial pathway in HepG2 cells.

Exploring the role of Azadirachta indica (neem) and its active compounds in the regulation of biological pathways: an update on molecular approach

In ethnomedicine, plant parts and compounds are used traditionally to treat different diseases. Neem (Azadirachta indica A. Juss) is the most versatile and useful medicinal plant ever found. Its every part is rich in bioactive compounds, which have traditionally been used to treat different ailments including infectious diseases. Bioactive compounds such as nimbolide, azarirachtin, and gedunin of neem are reported to have a tremendous ability to regulate numerous biological processes in vitro and in vivo. The present review article aims to explore the importance of neem extracts and bioactive compounds in the regulation of different biological pathways. We have reviewed research articles up to March 2020 on the role of neem in antioxidant, anti-inflammatory, antiangiogenic, immunomodulatory, and apoptotic activities. Studies on the concerned fields demonstrate that the bioactive compounds and extracts of neem have a regulatory effect on several biological mechanisms. It has been unveiled that extensive research is carried out on limonoids such as nimbolide and azarirachtin. It is evidenced by different studies that neem extracts are the potential to scavenge free radicals and reduce ROS-mediated damage to cells. Neem can be used to normalize lipid peroxidation and minimize ROS-mediated cell death. Besides, neem extracts can significantly reduce the release of proinflammatory cytokines and elevate the count of CD4 + and CD8 + T-cells. This review indicates the pivotal roles of A. indica in the regulation of different biological pathways. However, future investigations on other bioactive compounds of neem may reveal different therapeutic potentials.

Activated protein C and PAR1-derived and PAR3-derived peptides are anti-inflammatory by suppressing macrophage NLRP3 inflammasomes

Essentials Activated protein C (APC) is a serine protease with anticoagulant and cytoprotective effects. We tested whether APC or non-canonical PAR-derived peptides suppress inflammasome activity. APC or PAR1- and PAR3-derived peptides restrict inflammasome-dependent caspase-1 activity. Combined PAR1-derived and PAR3-derived peptides synergistically suppress caspase-1 activity. ABSTRACT: Background Activated protein C (APC) has been shown to restrict murine inflammasome activity. However, whether APC can exert anti-inflammatory activity in part through suppression of inflammasome activation in human systems is unknown. Objectives Studies were made to determine whether either APC or protease activated receptor (PAR)-derived peptides can reduce NLRP3 inflammasome activity in differentiated human THP-1 macrophage-like cells or in primary human monocytes stimulated to activate the inflammasome. Methods Human THP-1 cells or primary human monocytes were differentiated, treated with APC or PAR-derived peptides, and then stimulated with lipopolysaccharide and ATP to induce caspase-1 activity, a product of inflammasome activation. Results Activated protein C or noncanonical PAR1-derived or PAR3-derived peptides significantly reduced caspase-1 activity, detection of fluorescent NLRP3, and IL-1β release from THP-1 cells. At low concentrations where no effect was observed for each individual peptide, combinations of the PAR1-derived peptide and the PAR3-derived peptide resulted in a significant synergistic decrease in caspase-1 and IL-1β release. Caspase-1 activity was also reduced in primary human monocytes. Studies using blocking antibodies and small molecule PAR1 inhibitors suggest that EPCR, PAR1, and PAR3 each play roles in the observed anti-inflammatory effects. Several shortened versions of the PAR1- and PAR3-derived peptide reduced caspase-1 activity and exhibited synergistic anti-inflammatory effects. Conclusions The results indicate that both APC and certain PAR1- and PAR3-derived peptides, which are biased agonists for PAR1 or PAR3, can reduce inflammasome activity in stimulated human monocytes as measured by caspase-1 activity and IL-1β release and that PAR-derived biased peptide agonist combinations are synergistically anti-inflammatory.

A high-throughput AO/PI-based cell concentration and viability detection method using the Celigo image cytometry

To ensure cell-based assays are performed properly, both cell concentration and viability have to be determined so that the data can be normalized to generate meaningful and comparable results. Cell-based assays performed in immuno-oncology, toxicology, or bioprocessing research often require measuring of multiple samples and conditions, thus the current automated cell counter that uses single disposable counting slides is not practical for high-throughput screening assays. In the recent years, a plate-based image cytometry system has been developed for high-throughput biomolecular screening assays. In this work, we demonstrate a high-throughput AO/PI-based cell concentration and viability method using the Celigo image cytometer. First, we validate the method by comparing directly to Cellometer automated cell counter. Next, cell concentration dynamic range, viability dynamic range, and consistency are determined. The high-throughput AO/PI method described here allows for 96-well to 384-well plate samples to be analyzed in less than 7 min, which greatly reduces the time required for the single sample-based automated cell counter. In addition, this method can improve the efficiency for high-throughput screening assays, where multiple cell counts and viability measurements are needed prior to performing assays such as flow cytometry, ELISA, or simply plating cells for cell culture.