AMPK-Mediated Lysosome Biogenesis in Lung Cancer Growth

Identification and validation of eight lysosomes-related genes signatures and correlation with immune cell infiltration in lung adenocarcinoma

Lung cancer is the leading cause of cancer-related death. Lysosomes are key degradative compartments that maintain protein homeostasis. In current study, we aimed to construct a lysosomes-related genes signature to predict the overall survival (OS) of patients with Lung Adenocarcinoma (LUAD). Differentially expressed lysosomes-related genes (DELYs) were analyzed using The Cancer Genome Atlas (TCGA-LUAD cohort) database. The prognostic risk signature was identified by Least Absolute Shrinkage and Selection Operator (LASSO)-penalized Cox proportional hazards regression and multivariate Cox analysis. The predictive performance of the signature was assessed by Kaplan-Meier curves and Time-dependent receiver operating characteristic (ROC) curves. Gene set variant analysis (GSVA) was performed to explore the potential molecular biological function and signaling pathways. ESTIMATE and single sample gene set enrichment analysis (ssGSEA) were applied to estimate the difference of tumor microenvironment (TME) between the different risk subtypes. An eight prognostic genes (ACAP3, ATP8B3, BTK, CAV2, CDK5R1, GRIA1, PCSK9, and PLA2G3) signature was identified and divided patients into high-risk and low-risk groups. The prognostic signature was an independent prognostic factor for OS (HR > 1, p < 0.001). The molecular function analysis suggested that the signature was significantly correlated with cancer-associated pathways, including angiogenesis, epithelial mesenchymal transition, mTOR signaling, myc-targets. The low-risk patients had higher immune cell infiltration levels than high-risk group. We also evaluated the response to chemotherapeutic, targeted therapy and immunotherapy in high- and low-risk patients with LUAD. Furthermore, we validated the expression of the eight gene expression in LUAD tissues and cell lines by qRT-PCR. LYSscore signature provide a new modality for the accurate diagnosis and targeted treatment of LUAD and will help expand researchers' understanding of new prognostic models.

Sakurasosaponin inhibits lung cancer cell proliferation by inducing autophagy via AMPK activation

Sakurasosaponin (S-saponin; PubChem ID: 3085160), a recently identified saponin from the roots of Primula sieboldii, has shown potential anticancer properties against various types of cancer. In the present study, the effects of S-saponin on non-small cell lung cancer (NSCLC) cell proliferation and the underlying mechanisms, were investigated. The effect of S-saponin on cell proliferation and cell death were assessed CCK-8, clonogenic assay, western blotting and Annexin V/PI double staining. S-saponin-induced autophagy was determined by confocal microscopic analysis and immunoblotting. S-saponin inhibited the proliferation of A549 and H1299 NSCLC cell lines in a dose- and time-dependent manner, without inducing apoptosis. S-saponin treatment induced autophagy in these cells, as evidenced by the increased LC3-II levels and GFP-LC3 puncta formation. It activated the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway, which is crucial for autophagy induction. Inhibition of AMPK with Compound C or siRNA-mediated knockdown of AMPK abrogated S-saponin-induced autophagy and partially rescued cell proliferation. Therefore, S-saponin exerts anti-proliferative effects on NSCLC cells through autophagy induction via AMPK activation. Understanding the molecular mechanisms underlying the anticancer effects of S-saponin in NSCLC cells could provide insights for the development of novel therapeutic strategies for NSCLC.

Subtypes analysis and prognostic model construction based on lysosome-related genes in colon adenocarcinoma

Background: Lysosomes are essential for the development and recurrence of cancer. The relationship between a single lysosome-related gene and cancer has previously been studied, but the relationship between the lysosome-related genes (LRGs) and colon adenocarcinoma (COAD) remains unknown. This research examined the role of lysosome-related genes in colon adenocarcinoma. Methods: 28 lysosome-related genes associated with prognosis (PLRGs) were found by fusing the gene set that is differently expressed between tumor and non-tumor in colon adenocarcinoma with the gene set that is related to lysosomes. Using consensus unsupervised clustering of PLRGs, the colon adenocarcinoma cohort was divided into two subtypes. Prognostic and tumor microenvironment (TME) comparisons between the two subtypes were then made. The PLRGs_score was constructed using the least absolute shrinkage and selection operator regression (LASSO) method to quantify each patient's prognosis and provide advice for treatment. Lastly, Western Blot and immunohistochemistry (IHC) were used to identify MOGS expression at the protein level in colon adenocarcinoma tissues. Results: PLRGs had more somatic mutations and changes in genetic level, and the outcomes of the two subtypes differed significantly in terms of prognosis, tumor microenvironment, and enrichment pathways. Then, PLRGs_score was established based on two clusters of differential genes in the cancer genome atlas (TCGA) database, and external verification was performed using the gene expression omnibus (GEO) database. Then, we developed a highly accurate nomogram to enhance the clinical applicability of the PLRGs_score. Finally, a higher PLRGs_score was associated with a poorer overall survival (OS), a lower tumor mutation burden (TMB), a lower cancer stem cell (CSC) index, more microsatellite stability (MSS), and a higher clinical stage. MOGS was substantially elevated at the protein level in colon adenocarcinoma as additional confirmation. Conclusion: Overall, based on PLRGs, we identified two subtypes that varied significantly in terms of prognosis and tumor microenvironment. Then, in order to forecast patient prognosis and make treatment suggestions, we developed a diagnostic model with major significance for prognosis, clinical relevance, and immunotherapy. Moreover, we were the first to demonstrate that MOGS is highly expressed in colon adenocarcinoma.

AMPK-Mediated Metabolic Switching Is High Effective for Phytochemical Levo-Tetrahydropalmatine (l-THP) to Reduce Hepatocellular Carcinoma Tumor Growth

Targeting cancer cell metabolism has been an attractive approach for cancer treatment. However, the role of metabolic alternation in cancer is still unknown whether it functions as a tumor promoter or suppressor. Applying the cancer gene-metabolism integrative network model, we predict adenosine monophosphate-activated protein kinase (AMPK) to function as a central hub of metabolic landscape switching in specific liver cancer subtypes. For the first time, we demonstrate that the phytochemical levo-tetrahydropalmatine (l-THP), a Corydalis yanhusuo-derived clinical drug, as an AMPK activator via autophagy-mediated metabolic switching could kill the hepatocellular carcinoma HepG2 cells. Mechanistically, l-THP promotes the autophagic response by activating the AMPK-mTOR-ULK1 and the ROS-JNK-ATG cascades and impairing the ERK/AKT signaling. All these processes ultimately synergize to induce the decreased mitochondrial oxidative phosphorylation (OXPHOS) and mitochondrial damage. Notably, silencing AMPK significantly inhibits the autophagic flux and recovers the decreased OXPHOS metabolism, which results in HepG2 resistance to l-THP treatment. More importantly, l-THP potently reduces the growth of xenograft HepG2 tumor in nude mice without affecting other organs. From this perspective, our findings support the conclusion that metabolic change is an alternative approach to influence the development of HCC.

CDK4/6 inhibitors: a brief overview and prospective research directions

The discovery of cyclin-dependent kinases (CDK) and their mechanism in regulating the cell cycle process was considered a game-changer in cancer therapy. Cell cycle arrest and apoptosis were both triggered by their inhibition. The CDK4/6 complex acts as a checkpoint during the cell cycle transition from cell growth (G1) to DNA synthesis (S) phase and its deregulation or overexpression induces abnormal cell proliferation and cancer development. Consequently, targeting CDK4/6 has been proposed as a paradigm shift in the anticancer approach. The design and development of effective CDK4/6 inhibitors are increasingly becoming a promising cancer therapy evident with approved drugs such as palbociclib, ribociclib, and abemaciclib, etc. In this article, we explore the biological importance of CDK4/6 in cancer therapy, the development of resistance to monotherapy, and a short overview of PROTAC (Proteolysis Targeting Chimera), a unique and pioneering technique for degrading CDK4/6 enzymes. Overall, our prime focus is to discuss novel CDK4/6 inhibitors with diverse chemical classes and their correlation with computational studies.

The discovery of cyclin-dependent kinases (CDK) and their mechanism in regulating the cell cycle process was considered a game-changer in cancer therapy.

RSPH14 regulates the proliferation, cell cycle progression and apoptosis of non-small cell lung cancer cells

Non-small cell lung cancer (NSCLC) is the most common subtype of lung cancer and it is characterized by a high incidence. It is important to understand the molecular mechanisms that determine the progression and metastasis of NSCLC in order to develop more effective therapies and identify novel diagnostic indicators of NSCLC. RSPH14 has been reported to be related to multiple human diseases, including duodenal adenocarcinoma and meningiomas, but the role of RSPH14 in NSCLC remains unclear. The present study aimed to investigate the molecular function and clinical significance of RSPH14 in NSCLC. Analyses of public datasets and clinical samples demonstrated that RSPH14 expression was upregulated in NSCLC samples compared with normal samples. In addition, high RSPH14 expression was associated with a shorter overall survival time in patients with NSCLC. Notably, RSPH14 knockdown suppressed the proliferation and cell cycle progression, and enhanced the apoptosis of NSCLC cells. Mechanically, Tandem Mass Tag analysis demonstrated that RSPH14 can affect multiple processes, including the AMPK signaling pathway, calcium ion import regulation, glucose transmembrane transporter activity, and glucose transmembrane transport. Taken together, the results of the present study suggest that RSPH14 may be a promising prognostic factor and therapeutic target for NSCLC.

TSC2 regulates lysosome biogenesis via a non-canonical RAGC and TFEB-dependent mechanism

Tuberous Sclerosis Complex (TSC) is caused by TSC1 or TSC2 mutations, resulting in hyperactivation of the mechanistic target of rapamycin complex 1 (mTORC1). Transcription factor EB (TFEB), a master regulator of lysosome biogenesis, is negatively regulated by mTORC1 through a RAG GTPase-dependent phosphorylation. Here we show that lysosomal biogenesis is increased in TSC-associated renal tumors, pulmonary lymphangioleiomyomatosis, kidneys from Tsc2^+/- mice, and TSC1/2-deficient cells via a TFEB-dependent mechanism. Interestingly, in TSC1/2-deficient cells, TFEB is hypo-phosphorylated at mTORC1-dependent sites, indicating that mTORC1 is unable to phosphorylate TFEB in the absence of the TSC1/2 complex. Importantly, overexpression of folliculin (FLCN), a GTPase activating protein for RAGC, increases TFEB phosphorylation at the mTORC1 sites in TSC2-deficient cells. Overexpression of constitutively active RAGC is sufficient to relocalize TFEB to the cytoplasm. These findings establish the TSC proteins as critical regulators of lysosomal biogenesis via TFEB and RAGC and identify TFEB as a driver of the proliferation of TSC2-deficient cells.

Therapeutic potential of AMPK signaling targeting in lung cancer: Advances, challenges and future prospects

Lung cancer (LC) is a leading cause of death worldwide with high mortality and morbidity. A wide variety of risk factors are considered for LC development such as smoking, air pollution and family history. It appears that genetic and epigenetic factors are also potential players in LC development and progression. AMP-activated protein kinase (AMPK) is a signaling pathway with vital function in inducing energy balance and homeostasis. An increase in AMP:ATP and ADP:ATP ratio leads to activation of AMPK signaling by upstream mediators such as LKB1 and CamKK. Dysregulation of AMPK signaling is a common finding in different cancers, particularly LC. AMPK activation can significantly enhance LC metastasis via EMT induction. Upstream mediators such as PLAG1, IMPAD1, and TUFM can regulate AMPK-mediated metastasis. AMPK activation can promote proliferation and survival of LC cells via glycolysis induction. In suppressing LC progression, anti-tumor compounds including metformin, ginsenosides, casticin and duloxetine dually induce/inhibit AMPK signaling. This is due to double-edged sword role of AMPK signaling in LC cells. Furthermore, AMPK signaling can regulate response of LC cells to chemotherapy and radiotherapy that are discussed in the current review.

MicroRNA-217 inhibits the proliferation and invasion, and promotes apoptosis of non-small cell lung cancer cells by targeting sirtuin 1

Non-small cell lung cancer (NSCLC) is a common malignancy worldwide. MicroRNA (miR)-217 and sirtuin 1 (SIRT1) have been reported to play significant roles in different types of cancer, such as osteosarcoma and prostate cancer; however, the association between miR-217 and SIRT1 in the cell proliferation, apoptosis and invasion of NSCLC remain unknown. Thus, the present study aimed to investigate the roles of miR-217 and SIRT1 in NSCLC. The expression levels of miR-217 and SIRT1 were detected via reverse transcription-quantitative (RT-q)PCR and western blot analyses. The effect of miR-217 on A549 and H1299 cell proliferation, apoptosis and invasion was assessed via the Cell Counting Kit-8, flow cytometry and Transwell assays, respectively. In addition, the association between SIRT1 and miR-217 was predicted using the TargetScan database, and verified via the dual-luciferase reporter assay, and RT-qPCR and western blot analyses. The results demonstrated that miR-217 expression was significantly downregulated, while SIRT1 expression was significantly upregulated in A549 and H1299 cells compared with the human bronchial epithelial cells. Furthermore, transfection with miR-217 mimic significantly inhibited A549 and H1299 cell proliferation and invasion, and induced A549 and H1299 cell apoptosis. The results of the dual-luciferase reporter assay and western blot analysis confirmed that SIRT1 is a target gene of miR-217. In addition, miR-217 inhibited the activation of AMP-activated protein kinase (AMPK) and mTOR signaling. Taken together, the results of the present study suggest that miR-217 inhibits A549 and H1299 cell proliferation and invasion, and induces A549 and H1299 cell apoptosis by targeting SIRT1 and inactivating the SIRT1-mediated AMPK/mTOR signaling pathway. Thus, miR-217 may be used as a potential therapeutic target for the treatment of patients with NSCLC.

A High-Fat Diet Attenuates AMPK α1 in Adipocytes to Induce Exosome Shedding and Nonalcoholic Fatty Liver Development In Vivo

Exosomes are important for intercellular communication, but the role of exosomes in the communication between adipose tissue (AT) and the liver remains unknown. The aim of this study is to determine the contribution of AT-derived exosomes in nonalcoholic fatty liver disease (NAFLD). Exosome components, liver fat content, and liver function were monitored in AT in mice fed a high-fat diet (HFD) or treated with metformin or GW4869 and with AMPKα1-floxed (Prkaα1 ^fl/fl/wild-type [WT]), Prkaα1 ^-/-, liver tissue-specific Prkaα1 ^-/-, or AT-specific Prkaα1 ^-/- modification. In cultured adipocytes and white AT, the absence of AMPKα1 increased exosome release and exosomal proteins by elevating tumor susceptibility gene 101 (TSG101)-mediated exosome biogenesis. In adipocytes treated with palmitic acid, TSG101 facilitated scavenger receptor class B (CD36) sorting into exosomes. CD36-containing exosomes were then endocytosed by hepatocytes to induce lipid accumulation and inflammation. Consistently, an HFD induced more severe lipid accumulation and cell death in Prkaα1 ^-/- and AT-specific Prkaα1 ^-/- mice than in WT and liver-specific Prkaα1 ^-/- mice. AMPK activation by metformin reduced adipocyte-mediated exosome release and mitigated fatty liver development in WT and liver-specific Prkaα1 ^-/- mice. Moreover, administration of the exosome inhibitor GW4869 blocked exosome secretion and alleviated HFD-induced fatty livers in Prkaα1 ^-/- and adipocyte-specific Prkaα1 ^-/- mice. We conclude that HFD-mediated AMPKα1 inhibition promotes NAFLD by increasing numbers of AT CD36-containing exosomes.

WITHDRAWN: Dynamic Observation of Postoperative Infection and Neuron-specific Enolase Levels in Serum in Patients with Non-small Cell Lung Cancer According to Positron Emission Tomography-Computed Tomography

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Explaining the Genetic Causality for Complex Phenotype via Deep Association Kernel Learning

The genetic effect explains the causality from genetic mutations to the development of complex diseases. Existing genome-wide association study (GWAS) approaches are always built under a linear assumption, restricting their generalization in dissecting complicated causality such as the recessive genetic effect. Therefore, a sophisticated and general GWAS model that can work with different types of genetic effects is highly desired. Here, we introduce a deep association kernel learning (DAK) model to enable automatic causal genotype encoding for GWAS at pathway level. DAK can detect both common and rare variants with complicated genetic effects where existing approaches fail. When applied to four real-world GWAS datasets including cancers and schizophrenia, our DAK discovered potential casual pathways, including the association between dilated cardiomyopathy pathway and schizophrenia.

Redox regulation by SOD2 modulates colorectal cancer tumorigenesis through AMPK-mediated energy metabolism

Colorectal cancer (CRC) is a common malignancy. Many reports have implicated aberrant mitochondrial activity in the progression of CRC, with particular emphasis on the dysregulation of redox signaling and oxidative stress. In this study, we focused on manganese superoxide dismutase (MnSOD/SOD2), a key antioxidant enzyme, which maintains intracellular redox homeostasis. Current literature presents conflicting mechanisms for how SOD2 influences tumorigenesis and tumor progression. Here, we explored the role of SOD2 in CRC specifically. We found high levels of SOD2 expression in CRC tissues. We carried out a series of experiments to determine whether knockdown of SOD2 expression in CRC cell lines would reverse features of tumorigenesis. We found that reduced SOD2 expression decreased cell proliferation, migration, and invasion activity in CRC cells. Results from an additional series of experiments on mitochondrial function implicated a dual role for SOD2 in promoting CRC progression. First, proper level of SOD2 helped CRC cells maintain mitochondrial function by disposal of superoxide (O₂ ^.- ). Second, over-expression of SOD2 induced H₂ O₂ -mediated tumorigenesis by upregulating AMPK and glycolysis. Our results indicate that SOD2 may promote the occurrence and development of CRC by regulating the energy metabolism mediated by AMPK signaling pathways.