Autophagy inhibitor potentiates the antitumor efficacy of apatinib in uterine sarcoma by stimulating PI3K/Akt/mTOR pathway

CDKL3 Promotes Non-small Cell Lung Cancer by Suppressing Autophagy Via Activation of PI3K/Akt/mTOR Pathway

This study aimed to assess the role of cyclin-dependent kinase-like 3 (CDKL3) in the progression of non-small cell lung cancer (NSCLC) as well as the underlying mechanisms. Western blot and qRT-PCR were utilized to analyze CDKL3 expression in 30 pairs of NSCLC and paraneoplastic tissues. A549 cells with CDKL3 knockdown and PC9 cells with CDKL3 overexpression were constructed by infecting cells with lentiviruses expressing shRNA of CDKL3 and expressing a full-length CDKL3 mRNA, respectively. The CCK-8 assay, flow cytometry, wound healing assay, and Transwell assay were carried out to detect cell viability, apoptosis, migration, and invasion, respectively. Autophagosome morphology was observed by electron microscopy experiments, the expression of key components of the PI3K/Akt/mTOR pathway was examined via Western blot and their mRNA expression levels were determined. Besides, the stably infected NSCLC cells with reduced expression or overexpression of CDKL3 were inoculated into the right-back flank of mice to generate tumors. The results showed that CDKL3 expression was dramatically increased in NSCLC tissues. Moreover, CDKL3 promoted the viability and migration of NSCLC cells by suppressing autophagy in vitro and in vivo. In addition, CDKL3 might modulate PI3K/Akt/mTOR signaling in NSCLC. Overall, CDKL3 might promote NSCLC cell viability and metastasis by inhibiting autophagy and activating the PI3K/Akt/mTOR signaling pathway.

Design, synthesis and molecular docking of novel substituted azepines as inhibitors of PI3K/Akt/TSC2/mTOR signaling pathway in colorectal carcinoma

A series of novel substituted azepines (2-7) was synthesized using both traditional and ultrasonic techniques. The efficiency of the reaction rate and yield was improved by sonication technique. We identified the newly synthesized compounds based on their melting points, elemental analyses, and spectral data. Human cancers are regulated mainly by the phosphatidylinositol 3-kinase/protein kinases B (PI3K/Akt) pathway, and its abnormal activation is linked to carcinogenesis, and angiogenesis. Using in-silico studies, we evaluated the ability of all the novel substituted diazepines and oxazepines to prevent cancer growth and metastasis by targeting the PI3K/Akt signaling pathway. Based on our findings, compounds 4a and 7a were chosen for in-vitro testing as they ranked via molecular docking the highest binding energies of -10.9, -10.3, -10.6, and -10.4 kcal/mol respectively. Compounds 4a and 7a displayed significant cytotoxicity on Caco-2 colorectal cancer cells with IC₅₀ values of 8.445 ± 2.26 and 33.04 ± 2.06 μM, respectively. Additionally, they considerably suppressed the PI3K/Akt proteins and generated reactive oxygen species (ROS), which increased p53 and Bax, decreased Bcl-₂ levels, and arrested the cell cycle at sub-G0/G1 phase. We also observed a remarkable overexpression of the Tuberous Sclerosis Complex 2 (TSC2) gene, an inhibitor of the mammalian target of rapamycin (mTOR). These results showed that compounds 4a and 7a obeyed Lipinski's rule of five and might be potential cancer treatment scaffolds by preventing metastasis and proliferation via blocking the PI3K/Akt/TSC2/m-TOR signaling pathway. This supports our hypothesis that diazepine 4a and oxazepine 7a are promising drug candidates for colorectal cancer.

Enhancing Anti-Cancer Therapy with Selective Autophagy Inhibitors by Targeting Protective Autophagy

Autophagy is a process of eliminating damaged or unnecessary proteins and organelles, thereby maintaining intracellular homeostasis. Deregulation of autophagy is associated with several diseases including cancer. Contradictory dual roles of autophagy have been well established in cancer. Cytoprotective mechanism of autophagy has been extensively investigated for overcoming resistance to cancer therapies including radiotherapy, targeted therapy, immunotherapy, and chemotherapy. Selective autophagy inhibitors that directly target autophagic process have been developed for cancer treatment. Efficacies of autophagy inhibitors have been tested in various pre-clinical cancer animal models. Combination therapies of autophagy inhibitors with chemotherapeutics are being evaluated in clinal trials. In this review, we will focus on genetical and pharmacological perturbations of autophagy-related proteins in different steps of autophagic process and their therapeutic benefits. We will also summarize combination therapies of autophagy inhibitors with chemotherapies and their outcomes in pre-clinical and clinical studies. Understanding of current knowledge of development, progress, and application of cytoprotective autophagy inhibitors in combination therapies will open new possibilities for overcoming drug resistance and improving clinical outcomes.

Sestrin2 in cancer: a foe or a friend?

Sestrin2 is a conserved antioxidant, metabolism regulator, and downstream of P53. Sestrin2 can suppress oxidative stress and inflammation, thereby preventing the development and progression of cancer. However, Sestrin2 attenuates severe oxidative stress by activating nuclear factor erythroid 2-related factor 2 (Nrf2), thereby enhancing cancer cells survival and chemoresistance. Sestrin2 inhibits endoplasmic reticulum stress and activates autophagy and apoptosis in cancer cells. Attenuation of endoplasmic reticulum stress and augmentation of autophagy hinders cancer development but can either expedite or impede cancer progression under specific conditions. Furthermore, Sestrin2 can vigorously inhibit oncogenic signaling pathways through downregulation of mammalian target of rapamycin complex 1 (mTORC1) and hypoxia-inducible factor 1-alpha (HIF-1α). Conversely, Sestrin2 decreases the cytotoxic activity of T cells and natural killer cells which helps tumor cells immune evasion. Sestrin2 can enhance tumor cells viability in stress conditions such as glucose or glutamine deficiency. Cancer cells can also upregulate Sestrin2 during chemotherapy or radiotherapy to attenuate severe oxidative stress and ER stress, augment autophagy and resist the treatment. Recent studies unveiled that Sestrin2 is involved in the development and progression of several types of human cancer. The effect of Sestrin2 may differ depending on the type of tumor, for instance, several studies revealed that Sestrin2 protects against colorectal cancer, whereas results are controversial regarding lung cancer. Furthermore, Sestrin2 expression correlates with metastasis and survival in several types of human cancer such as colorectal cancer, lung cancer, and hepatocellular carcinoma. Targeted therapy for Sestrin2 or regulation of its expression by new techniques such as non-coding RNAs delivery and vector systems may improve cancer chemotherapy and overcome chemoresistance, metastasis and immune evasion that should be investigated by future trials.

ZDQ-0620, a Novel Phosphatidylinositol 3-Kinase Inhibitor, Inhibits Colorectal Carcinoma Cell Proliferation and Suppresses Angiogenesis by Attenuating PI3K/AKT/mTOR Pathway

The PI3K/AKT pathway plays a central role in human cancers, aberrant activation of this pathway is associated with tumorigenesis, cancer progression and angiogenesis. Based on the importance of the PI3K/AKT pathway in malignancies, we developed a 4-aminoquinazoline derivative, ZDQ-0620, initially envisioned as a novel pan-PI3K inhibitor. This study aimed to evaluate the potential target of ZDQ-0620 and its anticancer effect in human colorectal carcinoma (CRC). PI3K-kinase activity test showed IC50 of ZDQ-0620 against PI3Ka was 0.5 nM; molecular docking, CETSA assay and western blotting was further performed to predict ZDQ-0620 was a PI3K/AKT pathway inhibitor by targeting PI3K. To identify the effect of ZDQ-0620 on CRC cells, Sulforhodamine B (SRB) assay, flow cytometry, and Cell morphology analysis were conducted. The results showed that ZDQ-0620 inhibited the proliferation, migration and invasion of CRC cells, induced apoptosis through G0/G1 cell cycle arrest and mitochondrial pathway. Additionally, ZDQ-0620 inhibited the migration and tube formation of human umbilical vein endothelial cells (HUVECs). In vivo, neovascularization of rat aortic ring and chick chorioallantoic membrane (CAM) induced by VEGF was diminished when treated with ZDQ-0620. These results indicate that ZDQ-0620 induce apoptosis and anti-angiogenesis via inhibits the PI3K/AKT pathway. We suggest that the great potential of ZDQ-0620 as an effective treatment candidate against CRC.

Repeated social defeat stress inhibits development of hippocampus neurons through mitophagy and autophagy

The social defeat stress model is commonly used to study depression and anxiety disorder, which can significantly affect the structure and function of neurons in the hippocampus; however, the relevant mechanism in neuronal loss has not been clearly defined. In the present study, a social defeat stress model was established in mice to evaluate the impact of social defeat stress on the structure of neurons in the hippocampus using Western blotting, immunofluorescence, Nissl staining, Golgi staining and transmission electron microscopy. The results demonstrated that social defeat stress leads to disruption of homeostasis in the hippocampus and the integrity of mitochondria in hippocampal neurons was markedly affected by enhanced mitophagy and autophagy resulting in inhibition of development and growth. These findings provide new insights into the mechanisms of neuronal development and growth due to social defeat stress, which should help in the development of new strategies to combat the effects of depression and anxiety disorder.

The Enantiomer of Allopregnanolone Prevents Pressure-Mediated Retinal Degeneration Via Autophagy

In an ex vivo rat ocular hypertension (OHT) model, the neurosteroid allopregnanolone (AlloP) exerts neuroprotective effects via enhancement of both GABA_A receptors and autophagy. We now examine whether its enantiomer (ent-AlloP), which is largely inactive at GABA receptors, offers similar neuroprotection in ex vivo and in vivo rat OHT models. Ex vivo rat retinal preparations were incubated in a hyperbaric condition (10 and 75 mmHg) for 24 h. An in vivo ocular hypertension (OHT) model was induced by intracameral injection of polystyrene microbeads. We examined pharmacological effects of AlloP, ent-AlloP, picrotoxin (a GABA_A receptor antagonist), and 3-MA (an autophagy inhibitor) histologically and biochemically. We found that both AlloP and ent-AlloP have marked neuroprotective effects in the retina, but effects of the unnatural enantiomer are independent of GABA_A receptors. Electron microscopic analyses show that pressure elevation significantly increased autophagosomes (APs) in the nerve fiber layer and addition of AlloP also increased APs and degenerative autophagic vacuoles (AVds). ent-AlloP markedly increased APs and AVds compared to AlloP. Examination of LC3B-II and SQSTM1 protein levels using immunoblotting revealed that AlloP increased LC3B-II, and ent-AlloP further enhanced LC3B-II and suppressed SQSTM1, indicating that autophagy is a major mechanism underlying neuroprotection by ent-AlloP. In an rat in vivo OHT model, single intravitreal ent-AlloP injection prevented apoptotic cell death of retinal ganglion cells similar to AlloP. However, even in this model, ent-AlloP was more effective in activating autophagy than AlloP. We conclude that ent-AlloP may be a prototype of potential therapeutic for treatment of glaucoma as an autophagy enhancer without affecting GABA receptors.