In Silico Discovery of a Small Molecule Suppressing Lung Carcinoma A549 Cells Proliferation and Inducing Autophagy via mTOR Pathway Inhibition

Therapeutic strategies of targeting non-apoptotic regulated cell death (RCD) with small-molecule compounds in cancer

Regulated cell death (RCD) is a controlled form of cell death orchestrated by one or more cascading signaling pathways, making it amenable to pharmacological intervention. RCD subroutines can be categorized as apoptotic or non-apoptotic and play essential roles in maintaining homeostasis, facilitating development, and modulating immunity. Accumulating evidence has recently revealed that RCD evasion is frequently the primary cause of tumor survival. Several non-apoptotic RCD subroutines have garnered attention as promising cancer therapies due to their ability to induce tumor regression and prevent relapse, comparable to apoptosis. Moreover, they offer potential solutions for overcoming the acquired resistance of tumors toward apoptotic drugs. With an increasing understanding of the underlying mechanisms governing these non-apoptotic RCD subroutines, a growing number of small-molecule compounds targeting single or multiple pathways have been discovered, providing novel strategies for current cancer therapy. In this review, we comprehensively summarized the current regulatory mechanisms of the emerging non-apoptotic RCD subroutines, mainly including autophagy-dependent cell death, ferroptosis, cuproptosis, disulfidptosis, necroptosis, pyroptosis, alkaliptosis, oxeiptosis, parthanatos, mitochondrial permeability transition (MPT)-driven necrosis, entotic cell death, NETotic cell death, lysosome-dependent cell death, and immunogenic cell death (ICD). Furthermore, we focused on discussing the pharmacological regulatory mechanisms of related small-molecule compounds. In brief, these insightful findings may provide valuable guidance for investigating individual or collaborative targeting approaches towards different RCD subroutines, ultimately driving the discovery of novel small-molecule compounds that target RCD and significantly enhance future cancer therapeutics.

Assessment of mitophagy in human iPSC-derived cardiomyocytes

Defective mitophagy contributes to normal aging and various neurodegenerative and cardiovascular diseases. The newly developed methodologies to visualize and quantify mitophagy allow for additional progress in defining the pathophysiological significance of mitophagy in various model organisms. However, current knowledge regarding mitophagy relevant to human physiology is still limited. Model organisms such as mice might not be optimal models to recapitulate all the key aspects of human disease phenotypes. The development of the human-induced pluripotent stem cells (hiPSCs) may provide an exquisite approach to bridge the gap between animal mitophagy models and human physiology. To explore this premise, we take advantage of the pH-dependent fluorescent mitophagy reporter, mt-Keima, to assess mitophagy in hiPSCs and hiPSC-derived cardiomyocytes (hiPSC-CMs). We demonstrate that mt-Keima expression does not affect mitochondrial function or cardiomyocytes contractility. Comparison of hiPSCs and hiPSC-CMs during different stages of differentiation revealed significant variations in basal mitophagy. In addition, we have employed the mt-Keima hiPSC-CMs to analyze how mitophagy is altered under certain pathological conditions including treating the hiPSC-CMs with doxorubicin, a chemotherapeutic drug well known to cause life-threatening cardiotoxicity, and hypoxia that stimulates ischemia injury. We have further developed a chemical screening to identify compounds that modulate mitophagy in hiPSC-CMs. The ability to assess mitophagy in hiPSC-CMs suggests that the mt-Keima hiPSCs should be a valuable resource in determining the role mitophagy plays in human physiology and hiPSC-based disease models. The mt-Keima hiPSCs could prove a tremendous asset in the search for pharmacological interventions that promote mitophagy as a therapeutic target.Abbreviations: AAVS1: adeno-associated virus integration site 1; AKT/protein kinase B: AKT serine/threonine kinase; CAG promoter: cytomegalovirus early enhancer, chicken ACTB/β-actin promoter; CIS: cisplatin; CRISPR: clustered regularly interspaced short palindromic repeats; FACS: fluorescence-activated cell sorting; FCCP: carbonyl cyanide p-trifluoromethoxyphenylhydrazone; hiPSC: human induced pluripotent stem cell; hiPSC-CMs: human induced pluripotent stem cell-derived cardiomyocytes; ISO: isoproterenol; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PI3K: phosphoinositide 3-kinase; PINK1: PTEN induced kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; RT: room temperature; SB: SBI-0206965; ULK1: unc-51 like autophagy activating kinase 1.

Structural insights into the discrepant synergistic activity of Codlemone and (Z)-8-dodecenol towards Grapholita molesta pheromones

BACKGROUND

Insect pheromone synergists have been widely used to produce potent pheromone products for environment-friendly pest control. Codlemone (Cod) and (Z)-8-dodecenol (Dod) are two major Grapholita molesta pheromone synergists, with Cod having greater synergism and affinity for G. molesta pheromone binding protein 2 (GmolPBP2). Uncovering structural information key to the different binding affinity of Cod and Dod to GmolPBP2 would gain insights into what causes their synergy activity discrepancy.

RESULTS

Binding modes of the two synergists in the binding pocket of GmolPBP2 were analyzed and compared by molecular dynamics-based approaches. Although Cod and Dod were stabilized in a similar hydrophobic pocket, their interaction details with GmolPBP2 were divergent due to the extra double bond (C10═C11) in Cod. The C10═C11 improved the hydrophobic interactions of Cod with around residues. Such hydrophobic interaction improvement was also reflected in the raised importance of Phe11 in the GmolPBP2-Cod interaction. Not only that, the increased hydrophobic forces introduced by the C10═C11 changed the CH2-OH orientation in the GmolPBP2-Cod complex, which improved the H-bond interaction. Electrostatic complementarity analysis further indicated the positive role of C10═C11 in optimizing GmolPBP2-Cod interaction.

CONCLUSION

The C10═C11 is thought to contribute greatly to Cod's stronger synergy as a group key to the higher GmolPBP2-affinity, based on which the improvement directions for Cod and Dod were addressed as well. Our findings will aid in the development and optimization of more effective pheromone synergists, resulting in more effective pheromone-based pest management.

Exploring disordered loops in DprE1 provides a functional site to combat drug-resistance in Mycobacterium strains

As an anti-tuberculosis target, DprE1 contains two flexible loops (Loop I and Loop II) which have never been exploited for developing DprE1 inhibitors. Here Leu317 in Loop II was discovered as a new functional site to combat drug-resistance in Mycobacterium strains. Based on TCA1, LZDT1 was designed to optimize the hydrophobic interaction with Leu317. A subsequent biochemical and cellular assay displayed increased potency of LZDT1 in inhibiting DprE1 and killing drug-sensitive/-resistant Mycobacterium strains. The improved activity of LZDT1 and its analogue LZDT2 against multidrug resistant tuberculosis was particularly highlighted. For LZDT1, its enhanced interaction with Leu317 also impaired the drug-insensitivity of DprE1 caused by Cys387 mutation. A new nonbenzothiazole lead (LZDT10) with reduced Cys387-dependence was further produced by optimizing interactions with Leu317, improvement directions for LZDT10 were discussed as well. Our research underscores the value of potential functional sites in disordered loops, and affords a feasible way to develop these functional sites into opportunities for drug-resistance management.

Mapping of mTOR drug targets: Featured platforms for anti-cancer drug discovery

The mammalian/mechanistic target of rapamycin (mTOR) is a regulatory protein kinase involved in cell growth and proliferation. mTOR is usually assembled in two different complexes with different regulatory mechanisms, mTOR complex 1 (mTORC1) and mTORC2, which are involved in different functions such as cell proliferation and cytoskeleton assembly, respectively. In cancer cells, mTOR is hyperactivated in response to metabolic alterations and/or oncogenic signals to overcome the stressful microenvironments. Therefore, recent research progress for mTOR inhibition involves a variety of compounds that have been developed to disturb the metabolic processes of cancer cells through mTOR inhibition. In addition to competitive or allosteric inhibition, a new inhibition strategy that emerged mTOR complexes destabilization has recently been a concern. Here, we review the history of mTOR and its inhibition, along with the timeline of the mTOR inhibitors. We also introduce prospective drug targets to inhibit mTOR by disrupting the complexation of the components with peptides and small molecules.

Design and development of Tetrahydro-Quinoline derivatives as dual mTOR-C1/C2 inhibitors for the treatment of lung cancer

Lung cancer is one of the most prevailed cancer worldwide. Many genes get mutated in lung cancer but the involvement of EGFR, KRAS, PTEN and PIK3CA are more common. Unavailability of potent drugs and resistance to the available drugs are major concern in the treatment of lung cancer. In the present research, mTOR was selected as an important alternative target for the treatment of lung cancer which involves the PI3K/AKT/mTOR pathway. We studied binding interactions of AZD-2014 with the mTOR protein to identify important interactions required to design potent mTOR inhibitors which was supported by QSAR studies. Pharmacophore based virtual screening studies provided core scaffold, THQ. Based on molecular docking interactions, 31 THQ derivatives were synthesized and characterized. All compounds were screened for cellular mTOR enzyme assay along with antiproliferative activity against the panel of cancerous cell lines, from which 6 compounds were further screened for colony forming assay. Two most potent compounds, HB-UC-1 and HB-UC-5, were further screened for flow cytometry analysis, gene expression study and western blot analysis. Gene expression study revealed the efficiency of compound HB-UC-1 against both mTORC1 and mTORC2 by affecting downstream regulators of mTORC1 (E₄BP₄, eIF₄EBP₁) and mTORC2 (PCK1), respectively. In western blot analysis, both compounds, inhibited phosphorylation of AKT S473 which proved the efficiency these compounds against the mTORC2. These two compounds were further screened for in-vivo biological evaluation. Both compounds increased lifespan of cancer-bearing animals with improvement in mean survival time. Further, in bezopyrene induced lung cancer animal model, both compounds showed effectiveness through the biochemical parameters and histopathological evaluation of the lung tissue. In future, potent hit compound from this series could be modified to develop lead mTOR inhibitors for the treatment of lung cancer.

Quantitative Proteomic Analysis of Porcine Intestinal Epithelial Cells Infected with Porcine Deltacoronavirus Using iTRAQ-Coupled LC-MS/MS

Porcine deltacoronavirus (PDCoV) is an emergent enteropathogenic coronavirus associated with swine diarrhea. Porcine small intestinal epithelial cells (IPEC) are the primary target cells of PDCoV infection in vivo. Here, isobaric tags for relative and absolute quantification (iTRAQ) labeling coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantitatively identify differentially expressed proteins (DEPs) in PDCoV-infected IPEC-J2 cells. A total of 78 DEPs, including 23 upregulated and 55 downregulated proteins, were identified at 24 h postinfection. The data are available via ProteomeXchange with identifier PXD019975. To ensure reliability of the proteomics data, two randomly selected DEPs, the downregulated anaphase-promoting complex subunit 7 (ANAPC7) and upregulated interferon-induced protein with tetratricopeptide repeats 1 (IFIT1), were verified by real-time PCR and Western blot, and the results of which indicate that the proteomics data were reliable and valid. Bioinformatics analyses, including GO, COG, KEGG, and STRING, further demonstrated that a majority of the DEPs are involved in numerous crucial biological processes and signaling pathways, such as immune system, digestive system, signal transduction, RIG-I-like receptor, mTOR, PI3K-AKT, autophagy, and cell cycle signaling pathways. Altogether, this is the first study on proteomes of PDCoV-infected host cells, which shall provide valuable clues for further investigation of PDCoV pathogenesis.

ZhiShiXiaoPi tang inhibits autophagy induced by corticosterone and functional dyspepsia through blockade of the mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

ZhiShiXiaoPi Tang (ZSXPT) is a Chinese traditional medicine formula that contains 10 Chinese traditional medicine substances. It has been widely used to treat patients with functional dyspepsia (FD). However, the protective effect of ZSXPT and its molecular mechanisms in FD still remain elusive.

AIM OF THE STUDY

To investigate the protective effect of ZSXPT on autophagy induced by Corticosterone (Cort) in PC12 cells which have typical neuron characteristics and have been widely used as a model system for depression studies and FD rats, and explore its underlying mechanisms.

MATERIALS AND METHODS

In this study, high-performance liquid chromatography fingerprint analysis was performed to characterize the chemical composition of ZSXPT. Depression-induced autophagy, ROS generation, and changes in mitochondrial membrane potential (MMP) were investigated in Cort-induced PC12 cells and in FD rats to evaluate the protective effects of ZSXPT.

RESULTS

Our results show that ZSXPT treatment protects neurons against Cort-induced damage and apoptosis by increasing cell viability and reducing the release of lactate dehydrogenase. ZSXPT decreased Cort-induced ROS generation, increased MMP, and accelerated autophagy through the blockade of the mammalian target of rapamycin (mTOR) pathway. Moreover, we observed similar findings when we studied ZSXPT in a rat model of FD.

CONCLUSIONS

Our in vitro and in vivo results indicate that the neuroprotective effect of ZSXPT against autophagy-induced damage and apoptosis occurs mainly by blocking the mTOR pathway in Cort-induced PC12 cells and in FD rats. Taken together, these data provide reliable experimental evidence and explain the molecular mechanism by which ZSXPT ameliorates FD.