Apoptosis-based therapies

Exploring natural products as apoptosis modulators in cancers: insights into natural product-based therapeutic strategies

Cancer remains a leading cause of mortality globally, necessitating ongoing research and development of innovative therapeutic strategies. Natural products from plants, herbs, and marine species have shown great promise as anti-cancer therapies due to their bioactive components that alter cellular pathways, particularly apoptosis. This review explores the mechanism by which natural chemicals trigger the apoptosis of cancerous cells, which is crucial for eliminating them and halting tumor growth. These can affect the mitochondrial process by controlling the Bcl-2 protein family, increasing cytochrome c release, and activating caspases. They also activate death receptors like Fas and TRAIL to enhance the extrinsic apoptotic pathway. We focus on the main signaling channels involved, such as the endoplasmic reticulum (ER) stress-mediated apoptosis, extrinsic death receptor, and intrinsic mitochondrial pathways. The review explores the role of natural substances such as polyphenols, terpenoids, alkaloids, and flavonoids in promoting apoptotic cell death and increasing cancer cell susceptibility, potentially aiding in cancer treatments and the potential of combining natural products with traditional chemotherapeutic medicines to combat medication resistance and enhance therapeutic efficacy. Understanding cancer development involves inhibiting cell proliferation, regulating it, targeting apoptosis pathways, and using plant and marine extracts as apoptotic inducers.

Autophagy in brain tumors: molecular mechanisms, challenges, and therapeutic opportunities

Autophagy is responsible for maintaining cellular balance and ensuring survival. Autophagy plays a crucial role in the development of diseases, particularly human cancers, with actions that can either promote survival or induce cell death. However, brain tumors contribute to high levels of both mortality and morbidity globally, with resistance to treatments being acquired due to genetic mutations and dysregulation of molecular mechanisms, among other factors. Hence, having knowledge of the role of molecular processes in the advancement of brain tumors is enlightening, and the current review specifically examines the role of autophagy. The discussion would focus on the molecular pathways that control autophagy in brain tumors, and its dual role as a tumor suppressor and a supporter of tumor survival. Autophagy can control the advancement of different types of brain tumors like glioblastoma, glioma, and ependymoma, demonstrating its potential for treatment. Autophagy mechanisms can influence metastasis and drug resistance in glioblastoma, and there is a complex interplay between autophagy and cellular responses to stress like hypoxia and starvation. Autophagy can inhibit the growth of brain tumors by promoting apoptosis. Hence, focusing on autophagy could offer fresh perspectives on creating successful treatments.

The Mechanism of Damage to the Midgut by Low Concentration of Bacillus thuringiensis in the Silkworm, Bombyx mori

Bacillus thuringiensis (Bt) has been extensively applied in agricultural pest management, posing a notable ecological risk to beneficial insects like Bombyx mori (silkworms). However, the toxicological mechanisms of Bt at low concentrations on silkworms remain largely unexplored. In this study, we determined the LC50 (96 h) of Bt for fifth-instar silkworm larvae to be 0.08 × 10-3 mg/L. Exposure to a sub-lethal concentration of Bt (1/2 LC50) led to significant reductions in body weight, pupal size, and the weights of both the whole cocoon and cocoon shell. Histopathological and ultrastructural examinations revealed that Bt exposure caused severe damage to the microvilli and epidermal cells of the midgut. Transcriptome sequencing of the midgut identified 290 differentially expressed genes (DEGs), with these genes predominantly involved in metabolic processes and apoptotic pathways. Notably, apoptosis-related genes such as Apaf-1 and Caspase-3 were upregulated by 5.08-fold and 1.27-fold, respectively. Further validation through TUNEL assays and Western blotting analysis confirmed a significant activation of apoptotic signaling. These findings suggested that low concentrations of Bt could trigger apoptotic pathways in the midgut of silkworm larvae, providing valuable insights into the toxicological evaluation of Bt at sub-lethal doses in insect species.

Sensitivity and activation of endoplasmic reticulum stress response and apoptosis in the perinatal sheep heart

Although the unfolded protein response (UPR) contributes to survival by removing misfolded proteins, endoplasmic reticulum (ER) stress also activates proapoptotic pathways. Changed sensitivity to normal developmental stimuli may underlie observed cardiomyocyte apoptosis in the healthy perinatal heart. We determined in vitro sensitivity to thapsigargin in sheep cardiomyocytes from four perinatal ages. In utero cardiac activation of ER stress and apoptotic pathways was determined at these same ages. Thapsigargin-induced phosphorylation of eukaryotic initiation factor 2 (EIF2A) was decreased by 72% between 135 and 143 dGA (P = 0.0096) and remained low at 1 dPN (P = 0.0080). Conversely, thapsigargin-induced caspase cleavage was highest around the time of birth: cleaved caspase 3 was highest at 1 dPN (3.8-fold vs. 135 dGA, P = 0.0380; 7.8-fold vs. 5 dPN, P = 0.0118), cleaved caspase 7 and cleaved caspase 12 both increased between 135 and 143 dGA (25-fold and 6.9-fold respectively, both P < 0.0001) and remained elevated at 1 dPN. Induced apoptosis, measured by TdT-mediated dUTP nick-end labeling (TUNEL) assay, was highest around the time of birth (P < 0.0001). There were changes in myocardial ER stress pathway components in utero. Glucose (78 kDa)-regulated protein (GRP78) protein levels were high in the fetus and declined after birth (P < 0.0001). EIF2A phosphorylation was profoundly depressed at 1 dPN (vs. 143 dGA, P = 0.0113). In conclusion, there is dynamic regulation of ER proteostasis, ER stress, and apoptosis cascade in the perinatal heart. Apoptotic signaling is more readily activated in fetal cardiomyocytes near birth, leading to widespread caspase cleavage in the newborn heart. These pathways are important for the regulation of normal maturation in the healthy perinatal heart.NEW & NOTEWORTHY Cardiomyocyte apoptosis occurs even in the healthy, normally developing perinatal myocardium. As cardiomyocyte number is a critical contributor to heart health, the sensitivity of cardiomyocytes to endoplasmic reticulum stress leading to apoptosis is an important consideration. This study suggests that the heart has less robust protective mechanisms in response to endoplasmic reticulum stress immediately before and after birth, and that more cardiomyocyte death can be induced by stress in this period.

Curcuma wenyujin rhizomes extract ameliorates lipid accumulation

Curcuma wenyujin (C. wenyujin) is a medicinal plant that is traditionally used to treat blood stagnation, liver fibrosis, pain, and jaundice. In this study, we examined the effect of C. wenyujin rhizome extract on hepatic lipid accumulation both in vivo and in vitro. We found that the petroleum ether fraction of C. wenyujin rhizome extract (CWP) considerably reduced the accumulation of lipids in HepG2 cells treated with oleic and palmitic acid. Ultra-high-performance liquid chromatography coupled with LTQ-Orbitrap mass spectrometry was used to analyze the main chemical constituents of CWP, and 21 sesquiterpenes were identified. In vivo experiments revealed that the administration of CWP significantly reduced the body weight and serum total cholesterol (TC) level of low-density-lipoprotein receptor knockout mice treated with a high-fat diet without affecting their food intake. CWP also significantly reduced the levels of liver TC, liver triglycerides, aspartate transaminase, and alanine transaminase. Histological examination revealed that CWP dose-dependently reduced steatosis in liver tissue, significantly downregulated the expression of lipogenesis genes, and increased the β-oxidation of fatty acids. CWP also significantly increased autophagy-related proteins. In conclusion, CWP rich in sesquiterpenes reduces the accumulation of lipids in vivo and in vitro by improving lipid metabolism and activating autophagy.

Identification and Characterization of a Small Molecule Bcl-2 Functional Converter

Cancer cells exploit the expression of anti-apoptotic protein Bcl-2 to evade apoptosis and develop resistance to therapeutics. High levels of Bcl-2 leads to sequestration of pro-apoptotic proteins causing the apoptotic machinery to halt. In this study, we report discovery of a small molecule, BFC1108 (5-chloro-N-(2-ethoxyphenyl)-2-[(4-methoxybenzyol)amino]benzamide), which targets Bcl-2 and converts it into a pro-apoptotic protein. The apoptotic effect of BFC1108 is not inhibited, but rather potentiated, by Bcl-2 overexpression. BFC1108 induces a conformational change in Bcl-2, resulting in the exposure of its BH3 domain both in vitro and in vivo. BFC1108 suppresses the growth of triple-negative breast cancer xenografts with high Bcl-2 expression and inhibits breast cancer lung metastasis. This study demonstrates a novel approach to targeting Bcl-2 using BFC1108, a small molecule Bcl-2 functional converter that effectively induces apoptosis in Bcl-2-expressing cancers.

SIGNIFICANCE

We report the identification of a small molecule that exposes the Bcl-2 killer conformation and induces death in Bcl-2-expressing cancer cells. Selective targeting of Bcl-2 and elimination of cancer cells expressing Bcl-2 opens up new therapeutic avenues.

1-Benzyl-5-bromo-3-hydrazonoindolin-2-ones as Novel Anticancer Agents: Synthesis, Biological Evaluation and Molecular Modeling Insights

Human health is experiencing several obstacles in the modern medical era, particularly cancer. As a result, the cancer therapeutic arsenal should be continually expanded with innovative small molecules that preferentially target tumour cells. In this study, we describe the development of two small molecule series (7a–d and 12a–e) based on the 1-benzyl-5-bromoindolin-2-one scaffold that connected through a hydrazone linker to a 4-arylthiazole (7a–d) or 4-methyl-5-(aryldiazenyl)thiazole (12a–e) moiety. The anticancer activity of all the reported indolin-2-one derivatives was assessed against breast (MCF-7) and lung (A-549) cancer cell lines. The 4-arylthiazole-bearing derivatives 7c and 7d revealed the best anticancer activity toward MCF-7 cells (IC50 = 7.17 ± 0.94 and 2.93 ± 0.47, respectively). Furthermore, the VEGFR-2 inhibitory activity for 7c and 7d was evaluated. Both molecules disclosed good inhibitory activity, and their IC50 values were equal to 0.728 µM and 0.503 µM, respectively. Additionally, the impacts of 7d on the cell cycle phases as well as on the levels of different apoptotic markers (caspase-3, caspase-9, Bax, and Bcl-2) were assessed. Molecular docking and dynamic simulations are carried out to explore the binding mode of 7d within the VEGFR-2 active site.

Effects on Goat Meat Extracts on α-Glucosidase Inhibitory Activity, Expression of Bcl-2-Associated X (BAX), p53, and p21 in Cell Line and Expression of Atrogin-1, Muscle Atrophy F-Box (MAFbx), Muscle RING-Finger Protein-1 (MuRF-1), and Myosin Heavy Chain-7 (MYH-7) in C2C12 Myoblsts

This study examined the α-glucosidase inhibitory, and apoptosis- and anti-muscular-related factors of goat meat extracts from forelegs, hind legs, loin, and ribs. The goat meat extracts were evaluated for their α-glucosidase inhibitory activity. The gene and protein expression levels of Bcl-2-associated X (bax), p53, and p21 were examined by reverse transcription polymerase chain reaction (RT-PCR) and immunoblotting in AGS and HT-29 cells. The expression levels of Atrogin-1 and MHC1b were examined by RT-PCR in C2C12 myoblasts, and the expression levels of Atrogin-1, muscle atrophy F-box (MAFbx), muscle RING-finger protein-1 (MuRF-1), and myosin heavy chain-7 were investigated by immunoblotting. α-Glucosidase inhibitory activity was higher in ethanol extract than in hydrous and hot water extracts. BAX and p53 expression levels were higher (p<0.05) in AGS cells treated with goat meat extract than those of cells treated with no goat meat extract. In HT-29 cells, the protein expression levels of BAX, p53, and p21 were higher (p<0.05) in the cells treated with goat meat extract than those of cells not treated with goat meat extract. In dexamethasone-treated C2C12 cells, goat meat extract treatment lower (p<0.05) the expression of Atrogin-1 and lower (p<0.05) the expression of MAFbx and MuRF-1. The results of the present study indicate that goat meat extracts have α-glucosidase inhibitory activity in vitro. In addition, apoptosis was induced in AGS cells and HT-29 cells treated with goat meat extract, and anti-muscular atrophy activity was also observed in C2C12 cells treated with goat meat extract.

Synergistic therapeutic potential of alpelisib in cancers (excluding breast cancer): Preclinical and clinical evidences

The phosphoinositide 3-kinase (PI3K) signaling pathway is well-known for its important role in cancer growth, proliferation and migration. The activation of PI3K pathway is always connected with endocrine resistance and poor prognosis in cancers. Alpelisib, a selective inhibitor of PI3K, has been demonstrated to be effective in combination with endocrine therapy in HR+ PIK3CA-mutated advanced breast cancer in preclinical and clinical trials. Recently, the synergistic effects of alpelisib combined with targeted agents have been widely reported in PIK3CA-mutated cancer cells, such as breast, head and neck squamous cell carcinoma (HNSCC), cervical, liver, pancreatic and lung cancer. However, previous reviews mainly focused on the pharmacological activities of alpelisib in breast cancer. The synergistic therapeutic potential of alpelisib in other cancers has not yet been well reviewed. In this review, an extensive study of related literatures (published until December 20, 2022) regarding the anti-cancer functions and synergistic effects of alpelisib was carried out through the databases. Useful information was extracted. We summarized the preclinical and clinical studies of alpelisib in combination with targeted anti-cancer agents in cancer treatment (excluding breast cancer). The combinations of alpelisib and other targeted agents significantly improved the therapeutic efficacy both in preclinical and clinical studies. Unfortunately, synergistic therapies still could not effectively avoid the possible toxicities and adverse events during treatment. Finally, some prospects for the combination studies in cancer treatment were provided in the paper. Taken together, this review provided valuable information for alpelisib in preclinical and clinical applications.

Conjugated Linoleic Acid strengthens the apoptotic effect of low-dose cisplatin in A549 cells by inducing Bcl-2 downregulation

One of the chemotherapeutic agents widely used in the treatment of non-small cell lung cancer (NSCLC) is cisplatin. However, the resistance of cancer cells to cisplatin and additionally serious side effects from cisplatin limit its use. Conjugated linoleic acid (CLA) has been shown to suppress the development of carcinogenesis in vitro and in vivo studies and has antitumoral activity in many cancers. The study aimed to investigate the potential effect of using cisplatin, the first-line treatment for NSCLC, in combination with CLA to increase its efficacy in low-dose use. MTT cytotoxicity assay was performed to determine the effects of CLA in combination with cisplatin on cell viability of NSCLC cell lines. The apoptotic effect of this combination on NSCLC cell lines and cell cycle distribution was determined by flow cytometry. At the same time, apoptosis and cell cycle-related gene expression levels were determined by Real-Time PCR. Combination treatment of low-dose cisplatin with CLA resulted in a significant decrease in cell viability compared to cisplatin alone, and an increase in the rate of apoptotic cells was observed. While cisplatin caused G1 phase arrest in cancer cells, there was an increase in cell percentages in S and G2 phases after combined application with CLA. In high-dose cisplatin administration, it was observed that the efficiency of the decrease in anti-apoptotic BCL2 expression related to resistance to chemotherapeutic agents was less than that of low-dose cisplatin administration. Combined administration of high-dose cisplatin with CLA significantly recovered BCL2 downregulation.

Venetoclax analogs as promising anticancer therapeutics via targeting Bcl-2 protein: in-silico drug discovery study

B-cell lymphoma 2 (Bcl-2) protein plays a vital role in enhancing malignant cell survival by alleviating programmed cell death. Therefore, Bcl-2 protein has been identified as a charming druggable target for cancer treatment. Venetoclax has enticed considerable attention as a potential Bcl-2 inhibitor. Herein, in-silico computations were executed to search for new venetoclax analogs against the Bcl-2 protein. A library involving 4112 was collected, prepared, and virtually screened against Bcl-2 protein using AutoDock Vina1.1.2 software. Promising analogs in complex with Bcl-2 protein were further submitted to molecular dynamics (MD) simulations, pursued by binding energy computations using the MM-GBSA approach. Compared to venetoclax (ΔGbinding = -51.2 kcal/mol), PubChem-873-158-83 and PubChem-148-422-478 demonstrated greater binding affinities with Bcl-2 protein throughout 100 ns MD simulations with ΔGbinding values of -69.1 and -62.4 kcal/mol, respectively. Structural and energetical analyses unveiled good stabilization of the identified analogs complexed with Bcl-2 protein over the MD course. The pharmacokinetic features of the two identified analogs were anticipated and unveiled the oral bioavailability of these compounds. Further in-vitro/in-vivo biological evaluations around these compounds could assist in identifying anticancer leads towards Bcl-2 protein.Communicated by Ramaswamy H. Sarma.

Red Blood Cell Membrane-Camouflaged Gold Nanoparticles for Treatment of Melanoma

Background

Patients with melanoma have poor response and low long-term survival to conventional cisplatin (CP). Recently, biomimetic nanoparticles have played a significant role in tumor therapy. The purpose of this study was to mechanistically evaluate the effect of red blood cell membrane camouflaged gold nanoparticles loaded with CP (RBCm@AuNPs-CP) on enhancing chemotherapy in melanoma.

Methods

Treated B16-F10 cells with RBCm@AuNPs-CP, the antimelanoma effect in vitro was explored by detecting cell viability, apoptosis rate, level of reactive oxygen species (ROS), and singlet oxygen. RBCm@AuNPs-CP was injected into the melanoma-bearing mice via tail vein, and the target-ability, therapeutic effect, and toxicity were detected in melanoma tumor-bearing mice.

Results

RBCm@AuNPs-CP had an antiproliferation and apoptosis-inducing effect on B16-F10 cells, which might be mediated by oxidative stress of ROS, and its effect was significantly enhanced compared with the CP treatment group. In vivo experiments suggested the same outcome, with better target-ability of RBCm@AuNPs-CP.

Conclusion

The erythrocyte camouflage nanosystem RBCm@AuNPs-CP exhibited well passive tumor target-ability and promoted apoptosis of melanocytes by inducing ROS. RBCm@AuNPs-CP as a novel safe and effective targeted drug delivery system may provide a promising choice for the treatment of melanoma.

Alamandine, a new member of the renin-angiotensin system (RAS), attenuates collagen-induced arthritis in mice via inhibiting cytokine secretion in synovial fibroblasts

Alamandine is a novel component of the renin-angiotensin system (RAS) as well as an important biologically active peptide. It has predominantly been studied in cardiovascular context. However, its role in rheumatoid arthritis (RA) remains unknown. Here we illustrated its effects on inflammatory cytokines production by synovial fibroblasts from RA and pathological changes in collagen-induced arthritis (CIA) mice. Alamandine (0.1, 1 and 10 µg/ml) did not affect the survival of the synovial fibroblasts, but decreased the migration and proinflammatory cytokines expression in TNF-α (10 ng/ml) stimulated cells in vitro. Additionally, alamandine selectively decreased phosphorylated-JNK expression induced by TNF-a stimulation in RA FLS. DBA/1 J mice were induced arthritis by a primary injection with an emulsion of bovine type II collagen (CII) and complete Freund's adjuvant (day 0) and a booster injection of CII in incomplete Freund's adjuvant (day 21). Mice were then given alamandine intraperitoneally in saline (50 μg/kg/day) from days 21-42. Histology and multiplex immunobead assay showed that alamandine treatment inhibited the development of arthritis and reduced the joint damage. This effect was accompanied by the reduced inflammatory cytokines (IL-6, IL-23, IFN-γ) mRNA expression in local joints, the decreased TNF-α, IL-6, IL-17 and the increased IL-10 levels in the serum from alamandine administrated CIA mice. In conclusion, alamandine attenuates the development of arthritis by suppressing inflammatory cytokines expression in RA synovial fibroblasts via MAPK signaling pathway, suggesting a potential therapeutic role for RA.

A Novel Anti-CD22 scFv.Bim Fusion Protein Effectively Induces Apoptosis in Malignant B cells and Promotes Cytotoxicity

CD22 is a B-cell surface antigen which is highly expressed in cancerous B-cell lineages. Anti-CD22 antibodies are currently under focus as promising biologics against hematologic B-cell malignancies. Herein, we introduce a novel active recombinant anti-CD22 scFv.Bim fusion protein for targeting this cancerous antigen. An expression cassette encoding anti-CD22 scFv.Bim fusion protein was expressed in Pichia pastoris. The binding ability, cytotoxicity, and apoptotic activity of the purified recombinant protein against CD22⁺ Raji cell line were assessed by flow cytometry, microscopy, and MTT assay. Using bioinformatics, the 3D structure of the fusion protein and its interaction with CD22 were assessed. The in vitro binding analysis by immunofluorescence microscopy and flow cytometry demonstrated the specific binding of scFv.Bim to CD22⁺ Raji cells but not to CD22^- Jurkat cells. MTT data and Annexin V/PI flow cytometry analysis confirmed the apoptotic activity of anti-CD22 scFv.Bim against Raji cells but not Jurkat cells. In silico analysis also revealed the satisfactory stereochemical quality of the 3D model and molecular interactions toward CD22. This novel recombinant anti-CD22 scFv.Bim fusion protein could successfully deliver the pro-apoptotic peptide, BIM, to the target cells and thus nominates it as a promising molecule in treating B-cell malignancies.

Cell-penetrating peptide-mediated delivery of therapeutic peptides/proteins to manage the diseases involving oxidative stress, inflammatory response and apoptosis

OBJECTIVES

Peptides and proteins represent great potential for modulating various cellular processes including oxidative stress, inflammatory response, apoptosis and consequently the treatment of related diseases. However, their therapeutic effects are limited by their inability to cross cellular barriers. Cell-penetrating peptides (CPPs), which can transport cargoes into the cell, could resolve this issue, as would be discussed in this review.

KEY FINDINGS

CPPs have been successfully exploited in vitro and in vivo for peptide/protein delivery to treat a wide range of diseases involving oxidative stress, inflammatory processes and apoptosis. Their in vivo applications are still limited due to some fundamental issues of CPPs, including nonspecificity, proteolytic instability, potential toxicity and immunogenicity.

SUMMARY

Totally, CPPs could potentially help to manage the diseases involving oxidative stress, inflammatory response and apoptosis by delivering peptides/proteins that could selectively reach proper intracellular targets. More studies to overcome related CPP limitations and confirm the efficacy and safety of this strategy are needed before their clinical usage.

Severe cellular stress drives apoptosis through a dual control mechanism independently of p53

For past two decades, p53 has been claimed as the primary sensor initiating apoptosis. Under severe cellular stress, p53 transcriptional activity activates BH3-only proteins such as Bim, Puma, or Noxa to nullify the inhibitory effects of anti-apoptotic proteins on pro-apoptotic proteins for mitochondrial outer membrane permeabilization. Cellular stress determines the expression level of p53, and the amount of p53 corresponds to the magnitude of apoptosis. However, our studies indicated that Bim and Puma are not the target genes of p53 in three cancer models, prostate cancer, glioblastoma, and osteosarcoma. Bim counteracted with Bcl-xl to activate apoptosis independently of p53 in response to doxorubicin-induced severe DNA damage in prostate cancer. Moreover, the transcriptional activity of p53 was more related to cell cycle arrest other than apoptosis for responding to DNA damage stress generated by doxorubicin in prostate cancer and glioblastoma. A proteasome inhibitor that causes protein turnover dysfunction, bortezomib, produced apoptosis in a p53-independent manner in glioblastoma and osteosarcoma. p53 in terms of both protein level and nuclear localization in combining doxorubicin with bortezomib treatment was obviously lower than when using DOX alone, inversely correlated with the magnitude of apoptosis in glioblastoma. Using a BH3-mimetic, ABT-263, to treat doxorubicin-sensitive p53-wild type and doxorubicin-resistant p53-null osteosarcoma cells demonstrated only limited apoptotic response. The combination of doxorubicin or bortezomib with ABT-263 generated a synergistic outcome of apoptosis in both p53-wild type and p53-null osteosarcoma cells. Together, this suggested that p53 might have no role in doxorubicin-induced apoptosis in prostate cancer, glioblastoma and osteosarcoma. The effects of ABT-263 in single and combination treatment of osteosarcoma or prostate cancer indicated a dual control to regulate apoptosis in response to severe cellular stress. Whether our findings only apply in these three types of cancers or extend to other cancer types remains to be explored.

Modulation of histone deacetylase, the ubiquitin proteasome system, and autophagy underlies the neuroprotective effects of venlafaxine in a rotenone-induced Parkinson's disease model in rats

Parkinson's disease (PD) is a neurodegenerative disease characterized by motor and non-motor symptoms. Impairment of the ubiquitin proteasome system (UPS) and autophagy has been suggested to contribute to α-synuclein accumulation, which is identified as the pathological hallmark of PD. Recently, alteration in histone-3 acetylation has also been found to be correlated to PD. Interestingly, the histone deacetylase 6 (HDAC6) enzyme, which regulates the acetylation of histone-3, was shown to be involved in autophagy. Venlafaxine is an antidepressant that was proposed to inhibit HDAC expression in depressive rats' hippocampi. In this study, we aimed to examine the ability of venlafaxine to inhibit striatal HDAC6 and to enhance α-synuclein clearance through the activation of the UPS and autophagy, in addition to treating depression, which is the most debilitating non-motor symptom, in a rotenone model of PD. Venlafaxine administration was noted to decrease α-synuclein accumulation and preserve dopaminergic neurons along with restoration of striatal dopamine levels and motor recovery. Its administration augmented the UPS and autophagic markers (beclin-1, p62, and LC3) with consequent modulation of apoptotic indicators (Bax/Bcl-2 ratio, cytochrome c, and caspase-3). Additionally, venlafaxine inhibited HDAC6 with further enhancement of autophagy and restoration of histone-3 acetylation with subsequent increases in survival gene expressions (Bcl-2 and brain-derived neurotrophic factor). Chloroquine (autophagy inhibitor) was used to indicate the proposed pathway. Moreover, venlafaxine hampered depressive symptoms and improved hippocampal noradrenaline and serotonin levels. Collectively, venlafaxine is suggested to display neuroprotective effects with improvement of motor and non-motor PD symptoms.

The various regulatory functions of long noncoding RNAs in apoptosis, cell cycle, and cellular senescence

Long noncoding RNAs (lncRNAs) are a group of noncoding cellular RNAs involved in significant biological phenomena such as differentiation, cell development, genomic imprinting, adjusting the enzymatic activity, regulating chromosome conformation, apoptosis, cell cycle, and cellular senescence. The misregulation of lncRNAs interrupting normal biological processes has been implicated in tumor formation and metastasis, resulting in cancer. Apoptosis and cell cycle, two main biological phenomena, are highly conserved and intimately coupled mechanisms. Hence, some cell cycle regulators can influence both programmed cell death and cell division. Apoptosis eliminates defective and unwanted cells, and the cell cycle enables cells to replicate themselves. The improper regulation of apoptosis and cell cycle contributes to numerous disorders such as neurodegenerative and autoimmune diseases, viral infection, anemia, and mainly cancer. Cellular senescence is a tumor-suppressing response initiated by environmental and internal stress factors. This phenomenon has recently attained more attention due to its therapeutic implications in the field of senotherapy. In this review, the regulatory roles of lncRNAs on apoptosis, cell cycle, and senescence will be discussed. First, the role of lncRNAs in mitochondrial dynamics and apoptosis is addressed. Next, the interaction between lncRNAs and caspases, pro/antiapoptotic proteins, and also EGFR/PI3K/PTEN/AKT/mTORC1 signaling pathway will be investigated. Furthermore, the effect of lncRNAs in the cell cycle is surveyed through interaction with cyclins, cdks, p21, and wnt/β-catenin/c-myc pathway. Finally, the function of essential lncRNAs in cellular senescence is mentioned.

A Brief Introduction to Current Cancer Gene Therapy

Gene therapy has started in the late 1980s as novel, clinically applicable therapeutic option. It revolutionized the treatment of genetic diseases with the initial intent to repair or replace defective genes. Gene therapy has been adapted for treatment of malignant diseases to improve the outcome of cancer patients. In fact, cancer gene therapy has rapidly gained great interest and evolved into a research field with highest proportion of research activities in gene therapy. In this context, cancer gene therapy has long entered translation into clinical trials and therefore more than two-thirds of all gene therapy trials worldwide are aiming at the treatment of cancer disease using different therapeutic strategies. During the decades in cancer gene therapy, tremendous knowledge has accumulated. This led to significant improvements in vector design, transgene repertoire, more targeted interventions, use of novel gene therapeutic technologies such as CRISPR/Cas, sleeping beauty vectors, and development of effective cancer immunogene therapies. In this chapter, a brief overview of current key developments in cancer gene therapy is provided to gain insights into the recent directions in research as well as in clinical application of cancer gene therapy.

Marine-derived pipeline anticancer natural products: a review of their pharmacotherapeutic potential and molecular mechanisms

Background

Cancer is a complex and most widespread disease and its prevalence is increasing worldwide, more in countries that are witnessing urbanization and rapid industrialization changes. Although tremendous progress has been made, the interest in targeting cancer has grown rapidly every year. This review underscores the importance of preventive and therapeutic strategies.

Main text

Natural products (NPs) from various sources including plants have always played a crucial role in cancer treatment. In this growing list, numerous unique secondary metabolites from marine sources have added and gaining attention and became potential players in drug discovery and development for various biomedical applications. Many NPs found in nature that normally contain both pharmacological and biological activity employed in pharmaceutical industry predominantly in anticancer pharmaceuticals because of their enormous range of structure entities with unique functional groups that attract and inspire for the creation of several new drug leads through synthetic chemistry. Although terrestrial medicinal plants have been the focus for the development of NPs, however, in the last three decades, marine origins that include invertebrates, plants, algae, and bacteria have unearthed numerous novel pharmaceutical compounds, generally referred as marine NPs and are evolving continuously as discipline in the molecular targeted drug discovery with the inclusion of advanced screening tools which revolutionized and became the component of antitumor modern research.

Conclusions

This comprehensive review summarizes some important and interesting pipeline marine NPs such as Salinosporamide A, Dolastatin derivatives, Aplidine/plitidepsin (Aplidin®) and Coibamide A, their anticancer properties and describes their mechanisms of action (MoA) with their efficacy and clinical potential as they have attracted interest for potential use in the treatment of various types of cancers.

Colostrum fails to prevent bovine/camelid neonatal neutrophil damage from AFB1

Exposure to environmental toxicants that affect the immune system and overall health of many mammals is mostly unavoidable. One of the more common substances is the mycotoxins, especially carcinogenic aflatoxin (AF)B₁ which also causes immune suppression/dysregulation in exposed hosts. The present study analyzed the effects of naturally occurring levels of AFB₁ on apoptosis of healthy bovine and camelid neonatal neutrophils (PMN) that were isolated both before and after host consumption of colostrum. Cells from bovine and camel neonates (n = 12 sets of PMN/mammal/timepoint) were exposed for 24 h to a low level of AFB₁ (i.e. 10 ng AFB₁/ml) and then intracellular ATP content and caspase-3, -7, and -9 activities (determined by bioluminescence) were assessed. The results indicated a significant lessening of intracellular ATP content and equivalents of luminescence intensity in AFB₁-treated PMN in all studied samples, i.e. isolated pre-and post-colostrum consumption. In contrast, caspase-3, -7, and -9 activities in both pre- and post-colostrum consumption bovine and camelid PMN were noticeably increased (∼>2-fold). The damaging effects of AFB₁ were more pronounced in bovine neonate PMN than in camelid ones. These results showed that camelid or bovine neonatal PMN collected pre- and post-colostrum are sensitive (moreso after consumption) to naturally occurring levels of AFB₁. While merits of colostrum are well known, its failure to mitigate toxic effects of AFB₁ in what would translate into a critical period in the development of immune competence (i.e. during the first few days of life in bovine and camelid calves) is surprising. The observed in vitro toxicities can help clarify underlying mechanisms of immune disorders caused by AFs in animals/humans.

Neuroprotective gain of Apelin/APJ system

Apelin is an endogenous ligand of G protein-coupled receptor APJ. In recent years, many studies have shown that the apelin/APJ system has neuroprotective properties, such as anti-inflammatory, anti-oxidative stress, anti-apoptosis, and regulating autophagy, blocking excitatory toxicity. Apelin/APJ system has been proven to play a role in various neurological diseases and may be a promising therapeutic target for nervous system diseases. In this paper, the neuroprotective properties of the apelin/APJ system and its role in neurologic disorders are reviewed. Further understanding of the pathophysiological effect and mechanism of the apelin/APJ system in the nervous system will help develop new therapeutic interventions for various neurological diseases.

New epigenetic players in stroke pathogenesis: From non-coding RNAs to exosomal non-coding RNAs

Non-coding RNAs (ncRNAs) have critical role in the pathophysiology as well as recovery after ischemic stroke. ncRNAs, particularly microRNAs, and the long non-coding RNAs (lncRNAs) are critical for angiogenesis and neuroprotection, and they have been suggested to be therapeutic, diagnostic and prognostic tools in cerebrovascular diseases, including stroke. Moreover, exosomes have been considered as nanocarriers capable of transferring various cargos, such as lncRNAs and miRNAs to recipient cells, with prominent inter-cellular roles in the mediation of neuro-restorative events following strokes and neural injuries. In this review, we summarize the pathogenic role of ncRNAs and exosomal ncRNAs in the stroke.

Cyclopiazonic acid induced p53-dependent apoptosis in the testis of mice: Another male related risk factor of infertility

Cyclopiazonic acid (CPA) is an indole tetrameric acid mycotoxin. This study carried out to investigate the potential effects of CPA on male reproductive system. In the current study, 40 adult male mice were divided into five groups (n = 8). The control group did not expose to CPA, while animals in vehicle-received group; received the CPA-solvent (0.05% dimethyl sulfoxide) and the animals of third, fourth, and fifth groups received CPA 0.03, 0.06, and 0.12 mg/kg, body weight, respectively for 28 days. Morphometric and morphological deviations, spermatogenesis indices, malondialdehyde (MDA) content, total thiol molecules (TTM) concentration, total antioxidant capacity (TAC), protein carbonylation rate (CO), and nitric oxide (NO) concentration were examined. The expression changes of apoptotic genes (P53, Bcl-2, and Caspase III) at mRNA level were also evaluated by qPCR technique. Reduction in the Leydig and Sertoli cells population, diameter of seminiferous tubules, and spermatogenesis parameters was significant only in the group that received the highest dose of CPA. An increase in the level of MDA, NO, and CO in testicular tissue and reduction of TAC and TTM were observed in the CPA-exposed groups. Significant up-regulation (p < .05) in the expression of P53 and Caspase III genes and down-regulation of Bcl-2 gene were found in the CPA-received groups. These results are indicating the detrimental effects of CPA on the testicles, which may attribute to the CPA-induced oxidative stress and apoptosis. Moreover, results also help to understand a serious concern about the presence of CPA in foods as a potential risk factor in male-related infertility.

Structure-based design approach of potential BCL-2 inhibitors for cancer chemotherapy

B-cell lymphoma 2 (BCL-2) family is one of the chief regulators of cellular apoptosis. The intricate interactions between pro-apoptotic and anti-apoptotic genes of the BCL-2 family dictate the apoptotic balance of the cell. An overexpression of the anti-apoptotic members of BCL-2 is indicative of cell death evasion and cancer metastasis. Among the four BCL-2 homology domains, the BH3 domain plays a key role in the suppression of BCL-2 expression. Therefore, BH3-mimetic drugs are currently investigated for their suitability as BCL-2 inhibitors. In the present study, we followed a structure-based pharmacophore modelling approach to identify BH3-mimetic small molecules, to formulate a more precise and targeted cancer treatment regimen. To identify proteins with similar binding features, a structure-based pharmacophore model was generated based on the structure of Bcl-2 complexed with Venetoclax (PDB-ID:6O0K). Compounds with good fitness score and pharmacophore features, screened from the ZINC database, were subjected to (i) molecular docking studies, (ii) molecular mechanics-generalized Born surface area (MM-GBSA), and (iii) absorption, distribution, metabolism, excretion and toxicity (ADMET) prediction. From the analysis, two molecules were identified: ZINC68728276 and ZINC14166367, with docking scores of -7.323 and -8.649 kcal/mol and free binding energies (MM-GBSA) of -72.913 and -72.291 kcal/mol, respectively. The structural parameters and binding affinity of these complexes were validated through molecular dynamics simulation and molecular mechanics-Poisson-Boltzmann surface area (MM-PBSA) free energy calculations and compared with Venetoclax. The results indicated stability and good binding affinity of both the compounds. The study identified ZINC68728276 and ZINC14166367 as in silico potential Bcl-2 inhibitors, which can be further considered for in vitro studies.

Autophagic Cell Death During Development - Ancient and Mysterious

While cell death is a normal and essential component of development and homeostasis, dysregulation of this process underlies most human diseases, including cancer, autoimmunity and neurodegeneration. The best characterized mechanism for cell death is apoptosis, although some cells die by a distinct process known as autophagy-dependent cell death (ADCD). Autophagy is mediated by the formation of double membrane vesicles that contain protein aggregates, damaged organelles like mitochondria, and bulk cytoplasm, which then fuse with lysosomes to degrade and recycle their contents. Autophagy is typically viewed as an adaptive process that allows cells to survive stresses like nutrient deprivation, although increasing evidence suggests that it may also mediate cell death during development and pathogenesis. An aggressive form of autophagy termed autosis has been described in cells following either ischemia/reperfusion injury or in response to autophagy-inducing proteins like Tat-Beclin 1. Despite an extensive literature on autophagic cell death in a variety of contexts, there are still fundamental gaps in our understanding of this process. As examples: Does autophagy directly kill cells and if so how? Is ADCD activated concurrently when cells are triggered to die via apoptosis? And is ADCD essentially a more protracted version of autosis or a distinct pathway? The goal of this mini-review is to summarize the field and to identify some of the major gaps in our knowledge. Understanding the molecular mechanisms that mediate ADCD will not only provide new insights into development, they may facilitate the creation of better tools for both the diagnostics and treatment of disease.

Ethyl acetate extract of Tibetan medicine Rhamnella gilgitica ameliorated type II collagen-induced arthritis in rats via regulating JAK-STAT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Rhamnella gilgitica Mansf. et Melch. (སེང་ལྡེང་།, RG) is a traditional Tibetan medicinal plant that is currently grown throughout Tibet. According to the theory of Tibetan medicine, RG is efficient for removing rheumatism, reducing swelling, and relieving pain. Hence, it has been used for the treatment of rheumatoid arthritis (RA) in Tibet for many years. However, there are no previous reports on the anti-RA activities of ethyl acetate extract of RG (RGEA).

AIM OF THE STUDY

This study aimed to explore the anti-RA effect and mechanism of RGEA on collagen-induced arthritis (CIA) in rats.

MATERIALS AND METHODS

The CIA model was established in male Wister rats by intradermal injection of bovine type II collagen and Complete Freund's Adjuvant at the base of the tail and left sole, respectively. The rats were orally administered with RGEA (9.71, 19.43, or 38.85 mg/kg) for 23 days. The body weight, swelling volume, arthritis index score, thymus and spleen indices, and pathological changes were observed to evaluate the effect of RGEA on RA. Furthermore, the inflammatory cytokines in serum, such as interleukin1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), interleukin6 (IL-6), interleukin17 (IL-17), interferon-γ (INF-γ), interleukin4 (IL-4), and interleukin10 (IL-10) were measured by enzyme linked immunosorbent assay (ELISA) to explore the anti-inflammatory effects of RGEA. The terminal deoxynucleotidyl transferase dUTP nick-end labelling (TUNEL) staining was used to examine apoptosis. Finally, the protein and gene expression of B-cell lymphoma-2-associated X (Bax), B-cell lymphoma 2 (Bcl-2), Caspase3, janus-activated kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), suppressor of cytokine signaling1 (SOCS1), and 3 (SOCS3) in synovial tissue were detected using immunohistochemistry and real-time quantitative polymerase chain reaction (RT-qPCR).

RESULTS

After the treatment with RGEA, the body weight of rats was restored, both the arthritis index and paw swelling were suppressed, and spleen and thymus indices were decreased. RGEA reduced the inflammatory cells and synovial hyperplasia in the synovial tissue of the knee joint, and suppressed bone erosion. Meanwhile, RGEA decreased the levels of IL-1β, IL-6, IL-17, TNF-α, and INF-γ, while increased the levels of IL-4 and IL-10. TUNEL fluorescence apoptosis results confirmed that RGEA obviously promoted the apoptosis of synovial cells. Further studies showed that RGEA inhibited the proteins and mRNAs expression of JAK2 and STAT3 as well as increased the proteins and mRNAs expression of SOCS1 and SOCS3. In addition, RGEA upregulated the expression of Bax and Caspase3, and downregulated the expression of Bcl-2.

CONCLUSION

The anti-RA effectof RGEA might be related to the promotion of apoptosis and inhibition of inflammation, which regulated the JAK-STAT pathway.

Lipopolysaccharide Pre-conditioning Attenuates Pro-inflammatory Responses and Promotes Cytoprotective Effect in Differentiated PC12 Cell Lines via Pre-activation of Toll-Like Receptor-4 Signaling Pathway Leading to the Inhibition of Caspase-3/Nuclear Factor-κappa B Pathway

Lipopolysacharide (LPS) pre-conditioning (PC), has been shown to exert protective effects against cytotoxic effects. Therefore, we hypothesized, the tolerance produced by LPS PC will be resulted by the alterations and modifications in gene and protein expression. With reference to the results of MTT assays, AO/PI staining, and Annexin V-FITC analyses of LPS concentration (0.7815-50 μg/mL) and time-dependent (12-72 h) experiments, the pre-exposure to 3 μg/mL LPS for 12 h protected the differentiated PC12 cells against 0.75 mg/mL LPS apoptotic concentration. LPS-treated cells secreted more inflammatory cytokines like IL-1α, IL-1β, IL-2, IL-3, IL-4, IL-6, IL-17, IFN-γ, and TNF-α than LPS-PC cells. The production of inflammatory mediators ROS and NO was also higher in the LPS-induced cells compared to LPS-PC cells. Conversely, anti-inflammatory cytokines (like IL-10, IL-13, CNTF, and IL-1Ra) were upregulated in the LPS-PC cells but not in the LPS-induced cells. Meanwhile, the LPS initiated caspase-8 which in turn activates effector caspase 3/7. When the activities of caspases in the LPS-induced cells were inhibited using z-VADfmk and z-DEVDfmk, the expressions of c-MYC and Hsp70 were increased, but p53 was reduced. The potential molecules associated with protective and destructive effect was measured by RT² Profiler PCR array to elucidate the signaling pathways and suggested inhibition NF-κB/caspase-3 signaling pathway regulates the cytoprotective genes and proto-oncogenes. In conclusion, this study provides a basis for future research to better understand the molecular mechanism underlying LPS pre-conditioning /TLR4 pre-activation and its functional role in offering cytoprotective response in neuronal environment.

Combination strategies to overcome resistance to the BCL2 inhibitor venetoclax in hematologic malignancies

Venetoclax has been approved by the United States Food and Drug Administration since 2016 as a monotherapy for treating patients with relapsed/refractory chronic lymphocytic leukemia having 17p deletion. It has led to a breakthrough in the treatment of hematologic malignancies in recent years. However, unfortunately, resistance to venetoclax is inevitable. Multiple studies confirmed that the upregulation of the anti-apoptotic proteins of the B-cell lymphoma 2 (BCL2) family mediated by various mechanisms, such as tumor microenvironment, and the activation of intracellular signaling pathways were the major factors leading to resistance to venetoclax. Therefore, only targeting BCL2 often fails to achieve the expected therapeutic effect. Based on the mechanism of resistance in specific hematologic malignancies, the combination of specific drugs with venetoclax was a clinically optional treatment strategy for overcoming resistance to venetoclax. This study aimed to summarize the possible resistance mechanisms of various hematologic tumors to venetoclax and the corresponding clinical strategies to overcome resistance to venetoclax in hematologic malignancies.

An Artificial CTCF Peptide Triggers Efficient Therapeutic Efficacy in Ocular Melanoma

Although CCCTC binding factor (CTCF) has been demonstrated to play a variety of often contradictory roles in tumorigenesis, little is known about its function in the tumorigenesis of ocular melanoma. Here, we generated two artificial CTCF peptides (Decoy-CTCFs) combining the zinc finger domain of wild-type CTCF and artificial marker region. This Decoy-CTCF retained the DNA binding region but lost the functional regions of wild-type CTCF. Transferring artificial CTCF into ocular melanoma cells suppressed proliferation and migration in the tumor cells, while no effect was observed in normal cells. Intriguingly, we first showed that decoy-CTCF inhibited tumorigenesis by preventing the histone acetyltransferase EP300 from binding to the promoter of SELL. Thus SELL was a novel oncogene in the tumorigenesis of ocular melanoma. These studies provide efficient decoy CTCF-based therapeutic concept in malignant ocular melanoma and reveal the potential mechanism underlying decoy-based tumor therapy.

Development of [18F]ICMT-11 for Imaging Caspase-3/7 Activity during Therapy-Induced Apoptosis

Insufficient apoptosis is a recognised hallmark of cancer. A strategy to quantitatively measure apoptosis in vivo would be of immense value in both drug discovery and routine patient management. The first irreversible step in the apoptosis cascade is activation of the "executioner" caspase-3 enzyme to commence cleavage of key structural proteins. One strategy to measure caspase-3 activity is Positron Emission Tomography using isatin-5-sulfonamide radiotracers. One such radiotracer is [18F]ICMT-11, which has progressed to clinical application. This review summarises the design and development process for [18F]ICMT-11, suggesting potential avenues for further innovation.

Acheron/Larp6 Is a Survival Protein That Protects Skeletal Muscle From Programmed Cell Death During Development

The term programmed cell death (PCD) was coined in 1965 to describe the loss of the intersegmental muscles (ISMs) of moths at the end of metamorphosis. While it was subsequently demonstrated that this hormonally controlled death requires de novo gene expression, the signal transduction pathway that couples hormone action to cell death is largely unknown. Using the ISMs from the tobacco hawkmoth Manduca sexta, we have found that Acheron/LARP6 mRNA is induced ∼1,000-fold on the day the muscles become committed to die. Acheron functions as a survival protein that protects cells until cell death is initiated at eclosion (emergence), at which point it becomes phosphorylated and degraded in response to the peptide Eclosion Hormone (EH). Acheron binds to a novel BH3-only protein that we have named BBH1 (BAD/BNIP3 homology 1). BBH1 accumulates on the day the ISMs become committed to die and is presumably liberated when Acheron is degraded. This is correlated with the release and rapid degradation of cytochrome c and the subsequent demise of the cell. RNAi experiments in the fruit fly Drosophila confirmed that loss of Acheron results in precocious ecdysial muscle death while targeting BBH1 prevents death altogether. Acheron is highly expressed in neurons and muscles in humans and drives metastatic processes in some cancers, suggesting that it may represent a novel survival protein that protects terminally differentiated cells and some cancers from death.

Phenoxodiol sensitizes metastatic colorectal cancer cells to 5-fluorouracil- and oxaliplatin-induced apoptosis through intrinsic pathway

Colorectal cancer (CRC) is one of the most common types of cancer seen in the world. 5-Fluorouracil (5-Fu) plus Oxaliplatin (1-OHP) remains the backbone of CRC chemotherapeutics, but with limited success. Phenoxodiol (Pxd) is an isoflavone analog with antitumor activity against various types of cancers, and sensitizes chemoresistant cancer cells to chemotherapeutics including platinum and taxanes. This study was, therefore, undertaken to examine whether Pxd pre-treatment with conventional chemotherapeutic agent(s) 5-Fu and 1-OHP co-administration be a therapeutic strategy for CRC. Cell viability and cytotoxicity were evaluated using dimethyl-thiazolyl diphenyl tetrazolium bromide (MTT) and lactate dehydrogenase assays. The percentage of apoptotic and necrotic cells were determined by fluorescence microscopy analysis. Besides, active Caspase-3 levels by ELISA and relative mRNA levels of Caspase 3 (CASP3), CASP8 and CASP9 genes were determined by quantitative real-time PCR (qPCR) analysis. The pre-treatment of Pxd followed by 5-Fu and 1-OHP co-administration was more effective at inhibiting cell viability than either chemotherapeutic agents treatment alone. When compared to 5-Fu with 1-OHP alone treatment, Pxd pre-treatment overwhelmingly increased apoptotic Caspase-3 activity levels in CRC cells. Moreover, qPCR analyses showed that CASP3 and CASP9 mRNA levels significantly increased after pre-treatment with Pxd followed by 5-Fu and 1-OHP treatments, compared to 5-Fu with 1-OHP alone. Our results suggested that Pxd enhanced the in vitro antitumor activity of 5-Fu and 1-OHP. Our study also suggested that Pxd may be a potential candidate agent in advanced CRC and inclusion of Pxd to the conventional chemotherapeutic agent(s) could be an effective therapeutic strategy for CRC.

Integrating Ligand and Target-Driven Based Virtual Screening Approaches With in vitro Human Cell Line Models and Time-Resolved Fluorescence Resonance Energy Transfer Assay to Identify Novel Hit Compounds Against BCL-2

Antiapoptotic members of B-cell leukemia/lymphoma-2 (BCL-2) family proteins are one of the overexpressed proteins in cancer cells that are oncogenic targets. As such, targeting of BCL-2 family proteins raises hopes for new therapeutic discoveries. Thus, we used multistep screening and filtering approaches that combine structure and ligand-based drug design to identify new, effective BCL-2 inhibitors from a small molecule database (Specs SC), which includes more than 210,000 compounds. This database is first filtered based on binary “cancer-QSAR” model constructed with 886 training and 167 test set compounds and common 26 toxicity quantitative structure-activity relationships (QSAR) models. Predicted non-toxic compounds are considered for target-driven studies. Here, we applied two different approaches to filter and select hit compounds for further in vitro biological assays and human cell line experiments. In the first approach, a molecular docking and filtering approach is used to rank compounds based on their docking scores and only a few top-ranked molecules are selected for further long (100-ns) molecular dynamics (MD) simulations and in vitro tests. While docking algorithms are promising in predicting binding poses, they can be less prone to precisely predict ranking of compounds leading to decrease in the success rate of in silico studies. Hence, in the second approach, top-docking poses of each compound filtered through QSAR studies are subjected to initially short (1 ns) MD simulations and their binding energies are calculated via molecular mechanics generalized Born surface area (MM/GBSA) method. Then, the compounds are ranked based on their average MM/GBSA energy values to select hit molecules for further long MD simulations and in vitro studies. Additionally, we have applied text-mining approaches to identify molecules that contain “indol” phrase as many of the approved drugs contain indole and indol derivatives. Around 2700 compounds are filtered based on “cancer-QSAR” model and are then docked into BCL-2. Short MD simulations are performed for the top-docking poses for each compound in complex with BCL-2. The complexes are again ranked based on their MM/GBSA values to select hit molecules for further long MD simulations and in vitro studies. In total, seven molecules are subjected to biological activity tests in various human cancer cell lines as well as Time-Resolved Fluorescence Resonance Energy Transfer (TR-FRET) assay. Inhibitory concentrations are evaluated, and biological activities and apoptotic potentials are assessed by cell culture studies. Four molecules are found to be limiting the proliferation capacity of cancer cells while increasing the apoptotic cell fractions.

An early neuroprotective effect of atorvastatin against subarachnoid hemorrhage

Atorvastatin has been shown to reduce early brain edema and neuronal death after subarachnoid hemorrhage, but its mechanism is not clear. In this study, rat models of subarachnoid hemorrhage were established by autologous blood injection in the cisterna magna. Rat models were intragastrically administered 20 mg/kg atorvastatin 24 hours before subarachnoid hemorrhage, 12 and 36 hours after subarachnoid hemorrhage. Compared with the controls, atorvastatin treatment demonstrated that at 72 hours after subarachnoid hemorrhage, neurological function had clearly improved; brain edema was remarkably relieved; cell apoptosis was markedly reduced in the cerebral cortex of rats; the number of autophagy-related protein Beclin-1-positive cells and the expression levels of Beclin-1 and LC3 were increased compared with subarachnoid hemorrhage only. The ultrastructural damage of neurons in the temporal lobe was also noticeably alleviated. The similarities between the effects of atorvastatin and rapamycin were seen in all the measured outcomes of subarachnoid hemorrhage. However, these were contrary to the results of 3-methyladenine injection, which inhibits the signaling pathway of autophagy. These findings indicate that atorvastatin plays an early neuroprotective role in subarachnoid hemorrhage by activating autophagy. The experimental protocol was approved by the Animal Ethics Committee of Anhui Medical University, China (904 Hospital of Joint Logistic Support Force of PLA; approval No. YXLL-2017-09) on February 22, 2017.

Naturally Occurring Level of Aflatoxin B1 Injures Human, Canine and Bovine Leukocytes Through ATP Depletion and Caspase Activation

Aflatoxin (AF) B₁ is a potent hepatotoxic, mutagenic, teratogenic mycotoxin and may cause immune suppression/dysregulation in humans and animals. Toxic effects of AFB₁ on key mammalian immune cells (ie, leukocytes) needs to be mechanistically elucidated. In this study, along with the determination of AFB₁'s LC₅₀ for certain leukocytes, we analyzed the effect of naturally occurring levels of AFB₁ on apoptosis/necrosis of neutrophils, lymphocytes, and monocytes from healthy young humans (20- to 25-year-old male), dogs (1- to 2-year-old Persian/herd breed), and cattle (1- to 2-year-old cattle). Leukocytes were incubated for approximately 24 hours with naturally occurring levels of AFB₁ (10 ng/mL). Intracellular adenosine triphosphate (ATP) depletion and caspase-3/7 activity were then determined by luciferase-dependent bioluminescence (BL). Furthermore, the necrotic leukocytes were measured using propidium iodide (PI)-related flow cytometry. A significant decrease (24%-45%, 33.2% ± 2.7%) in intracellular ATP content was observed in AFB₁-treated neutrophils, lymphocytes, and monocytes in all studied mammals. Also, with such a low level (10 ng/mL) of AFB₁, BL-based caspase-3/7 activity (BL intensity) in all 3 tested mammalian leukocyte lineages was noticeably increased (∼>2-fold). Flow cytometry-based PI staining (for viability assay) of the AFB₁-treated leukocytes showed slightly/insignificantly more increase of necrotic (PI⁺) neutrophils, lymphocytes, and monocytes in human, dogs, and cattle. Even though in vitro LC₅₀s for AFB_1' (∼20,000-40,000 ng/mL) were approximately 2,000 to 4,000 times higher than background, these studies demonstrate leukocytes from human and farm/companion animals are sensitive to naturally occurring levels of AFB₁. The observed in vitro ATP depletion and caspase activation in AFB₁-exposed leukocytes can partially explain the underlying mechanisms of AFB₁-induced immune disorders in mammals.

Natural products targeting the PI3K-Akt-mTOR signaling pathway in cancer: A novel therapeutic strategy

The phosphatidylinositol 3-kinase (PI3K)-Akt and the mammalian target of rapamycin (mTOR) represent two vital intracellular signaling pathways, which are associated with various aspects of cellular functions. These functions play vital roles in quiescence, survival, and growth in normal physiological circumstances as well as in various pathological disorders, including cancer. These two pathways are so intimately connected to each other that in some instances these are considered as one unique pathway crucial for cell cycle regulation. The purpose of this review is to emphasize the role of PI3K-Akt-mTOR signaling pathway in different cancer conditions and the importance of natural products targeting the PI3K-Akt-mTOR signaling pathway. This review also aims to draw the attention of scientists and researchers to the assorted beneficial effects of the numerous classes of natural products for the development of new and safe drugs for possible cancer therapy. We also summarize and critically analyze various preclinical and clinical studies on bioactive compounds and constituents, which are derived from natural products, to target the PI3K-Akt-mTOR signaling pathway for cancer prevention and intervention.

One-Pot Radiosynthesis and Biological Evaluation of a Caspase-3 Selective 5-[123,125I]iodo-1,2,3-triazole derived Isatin SPECT Tracer

Induction of apoptosis is often necessary for successful cancer therapy, and the non-invasive monitoring of apoptosis post-therapy could assist in clinical decision making. Isatins are a class of compounds that target activated caspase-3 during apoptosis. Here we report the synthesis of the 5-iodo-1,2,3-triazole (FITI) analog of the PET tracer [18F]ICMT11 as a candidate tracer for imaging of apoptosis with SPECT, as well as PET. Labelling with radioiodine (123,125I) was achieved in 55 ± 12% radiochemical yield through a chelator-accelerated one-pot cycloaddition reaction mediated by copper(I) catalysis. The caspase-3 binding affinity and selectivity of FITI compares favourably to that of [18F]ICMT11 (Ki = 6.1 ± 0.9 nM and 12.4 ± 4.7 nM, respectively). In biodistribution studies, etoposide-induced cell death in a SW1222 xenograft model resulted in a 2-fold increase in tumour uptake of the tracer. However, the tumour uptake was too low to allow in vivo imaging of apoptosis with SPECT.

Cyclopalladated compounds containing 2,6-lutidine: Synthesis, spectral and biological studies

Bridge splitting reactions between [Pd(C²,N-dmba)(μ-X)]₂ (dmba = N,N-dimethylbenzylamine; X = Cl, I, N₃, NCO) and 2,6-lutidine (lut) in the 1:2 molar ratio at room temperature afforded cyclopalladated compounds of general formulae [Pd(C²,N-dmba)(X)(lut)] {X = Cl^- (1), I^-(2), NNN^-(3), NCO^-(4)}, which were characterized by elemental analyses and infrared (IR), ¹H NMR spectroscopy. The molecular structures of all synthesized palladacycles have been solved by single-crystal X-ray crystallography. The cytotoxicity of the cyclopalladated compounds has been evaluated against a panel of murine {mammary carcinoma (4T1) and melanoma (B16F10-Nex2)} and human {melanoma (A2058, SK-MEL-110 and SK-MEL-5) tumor cell lines. All complexes were about 10 to 100-fold more active than cisplatin, depending on the tested tumor cell line. For comparison purposes, the cytotoxic effects of 1-4 towards human lung fibroblasts (MRC-5) have also been tested. The late apoptosis-inducing properties of 1-4 compounds in SK-MEL-5 cells were verified 24 h incubation using annexin V-Fluorescein isothiocyanate (FITC)/propidium iodide (PI). The binding properties of the model compound 1 on human serum albumin (HSA) and calf thymus DNA (ct-DNA) have been studied using circular dichroism and fluorescence spectroscopy. Docking simulations have been carried out to gain more information about the interaction of the palladacycle and HSA. The ability of compounds 1-4 to inhibit the activity of cathepsin B and L has also been investigated in this work.

Synthesis of Substituted Cinnamido Linked Quinazolinone Congeners as Potential Anticancer Agents via Mitochondrial Dependent Intrinsic Apoptotic Pathway

BACKGROUND

The synthesis of novel heterocyclic scaffolds with amide functionality is a key research area due to their plethora of medicinal applications. The present study aims to explore the synthesis of new cinnamido linked quinazolinone congeners and their potential as anticancer agents.

METHODS

Cytotoxicity evaluation, Cell cycle analysis, JC-1 staining, ROS, Annexin V assays, AO/EB, DAPI nuclear staining, Colony-forming assay and Western blot analysis.

RESULTS

Among the synthesized compounds, 5eb and 5fc have shown promising cytotoxic activity with an IC50 value of 3.89±1.01µM and 4.05±0.62µM against HeLa cell lines. The flow-cytometry analysis demonstrated that the compound 5eb arrested the sub-G1 phase of the cell cycle and induced apoptosis. Furthermore, the compound 5eb triggered the collapse of mitochondrial membrane potential (ΔΨm), which was assessed by JC-1 staining and also induced the generation of Reactive Oxygen Species. An increase in the expression of proapoptotic proteins such as Bax, p53, cleaved PARP and cleaved caspase-3 by 5eb confirmed the activation of the mitochondrial-dependent intrinsic apoptosis pathway.

CONCLUSION

Our results suggest that compound 5eb and 5fc of cinnamido linked quinazolinone derivatives could serve as potential leads in the development of novel chemotherapeutic agents.

Novel Apoptosis-Inducing Agents for the Treatment of Cancer, a New Arsenal in the Toolbox

Evasion from apoptosis is an important hallmark of cancer cells. Alterations of apoptosis pathways are especially critical as they confer resistance to conventional anti-cancer therapeutics, e.g., chemotherapy, radiotherapy, and targeted therapeutics. Thus, successful induction of apoptosis using novel therapeutics may be a key strategy for preventing recurrence and metastasis. Inhibitors of anti-apoptotic molecules and enhancers of pro-apoptotic molecules are being actively developed for hematologic malignancies and solid tumors in particular over the last decade. However, due to the complicated apoptosis process caused by a multifaceted connection with cross-talk pathways, protein–protein interaction, and diverse resistance mechanisms, drug development within the category has been extremely challenging. Careful design and development of clinical trials incorporating predictive biomarkers along with novel apoptosis-inducing agents based on rational combination strategies are needed to ensure the successful development of these molecules. Here, we review the landscape of currently available direct apoptosis-targeting agents in clinical development for cancer treatment and update the related biomarker advancement to detect and validate the efficacy of apoptosis-targeted therapies, along with strategies to combine them with other agents.