Autophagosome accumulation-mediated ATP energy deprivation induced by penfluridol triggers nonapoptotic cell death of lung cancer via activating unfolded protein response

Penfluridol inhibits melanoma growth and metastasis through enhancing von Hippel‒Lindau tumor suppressor-mediated cancerous inhibitor of protein phosphatase 2A (CIP2A) degradation

Melanoma's high metastatic potential, especially to the brain, poses significant challenges to patient survival. The blood‒brain barrier (BBB) is a major obstacle to the effective treatment of melanoma brain metastases. We screened antipsychotic drugs capable of crossing the BBB and identified penfluridol (PF) as the most active candidate. PF reduced melanoma cell viability and induced apoptosis. In animal models, PF effectively inhibited melanoma growth and metastasis to the lung and brain. Using immunoprecipitation combined with high-resolution mass spectrometry, and other techniques such as drug affinity responsive target stability, we identified CIP2A as a direct binding protein of PF. CIP2A is highly expressed in melanoma and its metastases, and is linked to poor prognosis. PF can restore Protein Phosphatase 2A activity by promoting CIP2A degradation, thereby inhibiting several key oncogenic pathways, including AKT and c-Myc. Additionally, von Hippel‒Lindau (VHL) is the endogenous E3 ligase for CIP2A, and PF enhances the interaction between VHL and CIP2A, promoting the ubiquitin‒proteasome degradation of CIP2A, thereby inhibiting melanoma growth and metastasis. Overall, this study not only suggests PF's potential in treating melanoma and its brain metastases but also highlights CIP2A degradation as a therapeutic strategy for melanoma.

ESM1 facilitates the EGFR/HER3-triggered epithelial-to-mesenchymal transition and progression of gastric cancer via modulating interplay between Akt and angiopoietin-2 signaling

Gastric cancer (GC) poses global challenges due to its difficult early diagnosis and drug resistance, necessitating the identification of early detection markers and understanding of oncogenic pathways for effective GC therapy. Endothelial cell-specific molecule 1 (ESM1), a secreted glycoprotein, is elevated in various cancers, but its role in GC remains controversial. In our study, ESM1 was elevated in GC tissues, and its concentration was correlated with progression and poorer patient prognosis in independent cohorts. Functionally, ESM1 expression promoted proliferation, anoikis resistance, and motility of GC cells, as well as tumor growth in PDOs and in GC xenograft models. Mechanistically, ESM1 expression triggered the epithelial-to-mesenchymal transition (EMT) of GC cells by enhancing epidermal growth factor receptor (EGFR)/human EGFR 3 (HER3) association and activating the EGFR/HER3-Akt pathway. Additionally, angiopoietin-2 (ANGPT2) was found to be highly correlated with ESM1 and interplayed with Akt to induce the EMT and cancer progression. Use of a signal peptide deletion mutant (ESM1-19del) showed that the secreted form of ESM1 is crucial for its protumorigenic effects by activating the EGFR/HER3-Akt/ANGPT2 pathway to promote the EMT. Patients with high levels of both ESM1 and ANGPT2 had the poorest prognoses. Furthermore, therapeutic peptides successfully inhibited ESM1's induction of the aforementioned signals and motility of GC cells. ESM1's oncogenic role in GC involves activating the EGFR/HER3-Akt/ANGPT2 pathway, presenting a potential therapeutic target for GC.

Energy metabolism as the hub of advanced non-small cell lung cancer management: a comprehensive view in the framework of predictive, preventive, and personalized medicine

Energy metabolism is a hub of governing all processes at cellular and organismal levels such as, on one hand, reparable vs. irreparable cell damage, cell fate (proliferation, survival, apoptosis, malignant transformation etc.), and, on the other hand, carcinogenesis, tumor development, progression and metastazing versus anti-cancer protection and cure. The orchestrator is the mitochondria who produce, store and invest energy, conduct intracellular and systemically relevant signals decisive for internal and environmental stress adaptation, and coordinate corresponding processes at cellular and organismal levels. Consequently, the quality of mitochondrial health and homeostasis is a reliable target for health risk assessment at the stage of reversible damage to the health followed by cost-effective personalized protection against health-to-disease transition as well as for targeted protection against the disease progression (secondary care of cancer patients against growing primary tumors and metastatic disease). The energy reprogramming of non-small cell lung cancer (NSCLC) attracts particular attention as clinically relevant and instrumental for the paradigm change from reactive medical services to predictive, preventive and personalized medicine (3PM). This article provides a detailed overview towards mechanisms and biological pathways involving metabolic reprogramming (MR) with respect to inhibiting the synthesis of biomolecules and blocking common NSCLC metabolic pathways as anti-NSCLC therapeutic strategies. For instance, mitophagy recycles macromolecules to yield mitochondrial substrates for energy homeostasis and nucleotide synthesis. Histone modification and DNA methylation can predict the onset of diseases, and plasma C7 analysis is an efficient medical service potentially resulting in an optimized healthcare economy in corresponding areas. The MEMP scoring provides the guidance for immunotherapy, prognostic assessment, and anti-cancer drug development. Metabolite sensing mechanisms of nutrients and their derivatives are potential MR-related therapy in NSCLC. Moreover, miR-495-3p reprogramming of sphingolipid rheostat by targeting Sphk1, 22/FOXM1 axis regulation, and A2 receptor antagonist are highly promising therapy strategies. TFEB as a biomarker in predicting immune checkpoint blockade and redox-related lncRNA prognostic signature (redox-LPS) are considered reliable predictive approaches. Finally, exemplified in this article metabolic phenotyping is instrumental for innovative population screening, health risk assessment, predictive multi-level diagnostics, targeted prevention, and treatment algorithms tailored to personalized patient profiles-all are essential pillars in the paradigm change from reactive medical services to 3PM approach in overall management of lung cancers. This article highlights the 3PM relevant innovation focused on energy metabolism as the hub to advance NSCLC management benefiting vulnerable subpopulations, affected patients, and healthcare at large.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00357-5.

Acute kidney injury: exploring endoplasmic reticulum stress-mediated cell death

Acute kidney injury (AKI) is a global health problem, given its substantial morbidity and mortality rates. A better understanding of the mechanisms and factors contributing to AKI has the potential to guide interventions aimed at mitigating the risk of AKI and its subsequent unfavorable outcomes. Endoplasmic reticulum stress (ERS) is an intrinsic protective mechanism against external stressors. ERS occurs when the endoplasmic reticulum (ER) cannot deal with accumulated misfolded proteins completely. Excess ERS can eventually cause pathological reactions, triggering various programmed cell death (autophagy, ferroptosis, apoptosis, pyroptosis). This article provides an overview of the latest research progress in deciphering the interaction between ERS and different programmed cell death. Additionally, the report consolidates insights into the roles of ERS in AKI and highlights the potential avenues for targeting ERS as a treatment direction toward for AKI.

Cyclic increase in the ADAMTS1-L1CAM-EGFR axis promotes the EMT and cervical lymph node metastasis of oral squamous cell carcinoma

The matrix metalloprotease A disintegrin and metalloprotease with thrombospondin motifs 1 (ADAMTS1) was reported to be involved in tumor progression in several cancer types, but its contributions appear discrepant. At present, the role of ADAMTS1 in oral squamous cell carcinoma (SCC; OSCC) remains unclear. Herein, The Cancer Genome Atlas (TCGA) database showed that ADAMTS1 transcripts were downregulated in head and neck SCC (HNSCC) tissues compared to normal tissues, but ADAMTS1 levels were correlated with poorer prognoses of HNSCC patients. In vitro, we observed that ADAMTS1 expression levels were correlated with the invasive abilities of four OSCC cell lines, HSC-3, SCC9, HSC-3M, and SAS. Knockdown of ADAMTS1 in OSCC cells led to a decrease and its overexpression led to an increase in cell-invasive abilities in vitro as well as tumor growth and lymph node (LN) metastasis in OSCC xenografts. Mechanistic investigations showed that the cyclic increase in ADAMTS1-L1 cell adhesion molecule (L1CAM) axis-mediated epidermal growth factor receptor (EGFR) activation led to exacerbation of the invasive abilities of OSCC cells via inducing epithelial-mesenchymal transition (EMT) progression. Clinical analyses revealed that ADAMTS1, L1CAM, and EGFR levels were all correlated with worse prognoses of HNSCC patients, and patients with ADAMTS1high/L1CAMhigh or EGFRhigh tumors had the shortest overall and disease-specific survival times. As to therapeutic aspects, we discovered that an edible plant-derived flavonoid, apigenin (API), drastically inhibited expression of the ADAMTS1-L1CAM-EGFR axis and reduced the ADAMTS1-triggered invasion and LN metastasis of OSCC cells in vitro and in vivo. Most importantly, API treatment significantly prolonged survival rates of xenograft mice with OSCC. In summary, ADAMTS1 may be a useful biomarker for predicting OSCC progression, and API potentially retarded OSCC progression by targeting the ADAMTS1-L1CAM-EGFR signaling pathway.

Differential Cellular Interactome in Schizophrenia and Bipolar Disorder-Discriminatory Biomarker Role

Schizophrenia (SCH) and bipolar disorder (BD) are two of the most important psychiatric pathologies due to their high population incidence and disabling power, but they also present, mainly in their debut, high clinical similarities that make their discrimination difficult. In this work, the differential oxidative stress, present in both disorders, is shown as a concatenator of the systemic alterations-both plasma and erythrocyte, and even at the level of peripheral blood mononuclear cells (PBMC)-in which, for the first time, the different affectations that both disorders cause at the level of the cellular interactome were observed. A marked erythrocyte antioxidant imbalance only present in SCH generalizes to oxidative damage at the plasma level and shows a clear impact on cellular involvement. From the alteration of protein synthesis to the induction of death by apoptosis, including proteasomal damage, mitochondrial imbalance, and autophagic alteration, all the data show a greater cellular affectation in SCH than in BD, which could be linked to increased oxidative stress. Thus, patients with SCH in our study show increased endoplasmic reticulum (ER)stress that induces increased proteasomal activity and a multifactorial response to misfolded proteins (UPR), which, together with altered mitochondrial activity, generating free radicals and leading to insufficient energy production, is associated with defective autophagy and ultimately leads the cell to a high apoptotic predisposition. In BD, however, oxidative damage is much milder and without significant activation of survival mechanisms or inhibition of apoptosis. These clear differences identified at the molecular and cellular level between the two disorders, resulting from progressive afflictions in which oxidative stress can be both a cause and a consequence, significantly improve the understanding of both disorders to date and are essential for the development of targeted and preventive treatments.

Penfluroidol Attenuates the Imbalance of the Inflammatory Response by Repressing the Activation of the NLRP3 Inflammasome and Reduces Oxidative Stress via the Nrf2/HO-1 Signaling Pathway in LPS-Induced Macrophages

Objectives

Excessive inflammatory responses and reactive oxygen species (ROS) formation play pivotal roles in the pathogenesis of sepsis. Penfluroidol (PF), an oral long-acting antipsychotic drug, has been suggested to possess diverse biological properties, including antischizophrenia, antitumour effect, and anti-inflammatory activity. The purpose of this research was to explore the anti-inflammatory and antioxidative effects of penfluroidol on lipopolysaccharide (LPS)-related macrophages.

Methods

The viability of RAW264.7 and THP-1 cells was measured by Enhanced Cell Counting Kit-8 (CCK-8). The production of nitric oxide was evaluated by the Nitric Oxide Assay Kit. The generation of pro-inflammatory monocytes was detected by qRT-PCR (quantitative real-time PCR) and ELISA (enzyme-linked immunosorbent assay). Oxidative stress was assessed by measuring ROS, malondialdehyde (MDA), and superoxide dismutase (SOD) activity. The protein expression of the Nrf2/HO-1/NLRP3 inflammasome was detected by western blotting.

Results

Our results indicated that no cytotoxic effect was observed when RAW264.7 and THP-1 cells were exposed to PF (0-1 μm) and/or LPS (1 μg/ml) for 24 hr. The data showed that LPS, which was repressed by PF, facilitated the generation of the pro-inflammatory molecules TNF-α and IL-6. In addition, LPS contributed to increased production of intracellular ROS compared with the control group, whereas the administration of PF effectively reduced LPS-related levels of ROS. Moreover, LPS induced the generation of MDA and suppressed the activities of SOD. However, PF treatment strongly decreased LPS-induced MDA levels and increased SOD activities in the RAW264.7 and THP-1 cells. Furthermore, our research confirmed that penfluroidol repressed the secretion of pro-inflammatory molecules by limiting the activation of the NLRP3 inflammasome and reducing oxidative effects via the Nrf2/HO-1 signaling pathway.

Conclusion

Penfluroidol attenuated the imbalance of the inflammatory response by suppressing the activation of the NLRP3 inflammasome and reduced oxidative stress via the Nrf2/HO-1 signaling pathway in LPS-induced macrophages.

Treatment of cancer with antipsychotic medications: Pushing the boundaries of schizophrenia and cancer

Over a century ago, the phenothiazine dye, methylene blue, was discovered to have both antipsychotic and anti-cancer effects. In the 20th-century, the first phenothiazine antipsychotic, chlorpromazine, was found to inhibit cancer. During the years of elucidating the pharmacology of the phenothiazines, reserpine, an antipsychotic with a long historical background, was likewise discovered to have anti-cancer properties. Research on the effects of antipsychotics on cancer continued slowly until the 21st century when efforts to repurpose antipsychotics for cancer treatment accelerated. This review examines the history of these developments, and identifies which antipsychotics might treat cancer, and which cancers might be treated by antipsychotics. The review also describes the molecular mechanisms through which antipsychotics may inhibit cancer. Although the overlap of molecular pathways between schizophrenia and cancer have been known or suspected for many years, no comprehensive review of the subject has appeared in the psychiatric literature to assess the significance of these similarities. This review fills that gap and discusses what, if any, significance the similarities have regarding the etiology of schizophrenia.

GFAT1-linked TAB1 glutamylation sustains p38 MAPK activation and promotes lung cancer cell survival under glucose starvation

Reprogrammed cell metabolism is deemed as one of the hallmarks of cancer. Hexosamine biosynthesis pathway (HBP) acts as an “energy sensor” in cells to regulate metabolic fluxes. Glutamine-fructose-6-phosphate amidotransferase 1 (GFAT1), the rate-limiting enzyme of HBP, is broadly found with elevated expression in human cancers though its exact and concrete role in tumorigenesis still remains unknown and needs further investigation. P38 mitogen-activated protein kinase (MAPK) is an important component of stress-signaling pathway and plays a critical role in cell fate decision, whereas the underlying mechanism of its activation under nutrient stress also remains elusive. In this study, we show that glucose deprivation induces the interaction of GFAT1 with transforming growth factor β-activated kinase 1 binding protein 1 (TAB1) in a TAB1 S438 phosphorylation-dependent manner. Subsequently, the binding of GFAT1 to TAB1 facilitates TTLL5–GFAT1–TAB1 complex formation, and the metabolic activity of GFAT1 for glutamate production further contributes to TTLL5-mediated TAB1 glutamylation. In consequence, TAB1 glutamylation promotes the recruitment of p38α MAPK and thus drives p38 MAPK activation. Physiologically, GFAT1-TAB1-p38 signaling promotes autophagy occurrence and thus protects tumor cell survival under glucose deficiency. Clinical analysis indicates that both GFAT1 and TAB1 S438 phosphorylation levels correlate with the poor prognosis of lung adenocarcinoma patients. These findings altogether uncover an unidentified mechanism underlying p38 MAPK signaling regulation by metabolic enzyme upon nutrient stress and provide theoretical rationality of targeting GFAT1 for cancer treatment.

Inhibition of AMPK/PFKFB3 mediated glycolysis synergizes with penfluridol to suppress gallbladder cancer growth

BACKGROUND

Penfluridol (PF) is an FDA-approved antipsychotic drug that has recently been shown to have anticancer activity. However, the anticancer effects and underlying mechanisms of PF are not well-established in gallbladder cancer (GBC).

METHODS

The anticancer efficacy of PF on GBC was investigated via a series of cell functions experiments, including cell viability, colony formation, apoptosis assays, and so on. The corresponding signaling changes after PF treatment were explored by western blotting. Then, nude mice were utilized to study and test the anticancer activity of PF in vivo. Besides, glucose consumption and lactic production assays were used to detect the glycolysis alteration.

RESULTS

In this study, we discovered that PF greatly inhibited the proliferation and invasion ability of GBC cells (GBCs). The glucose consumption and lactic generation ability of GBCs were dramatically elevated following PF treatment. Additionally, we discovered that inhibiting glycolysis could improve PF's anticancer efficacy. Further studies established that the activation of the AMPK/PFKFB3 signaling pathway medicated glycolysis after PF treatment. We proved mechanistically that inhibition of AMPK/PFKFB3 singling pathway mediated glycolysis was a potential synergetic strategy to improve the anticancer efficacy of PF on GBC.

CONCLUSIONS

By inhibiting AMPK, the anticancer effects of PF on GBCs were amplified. As a result, our investigations shed new light on the possibility of repurposing PF as an anticancer drug for GBC, and AMPK inhibition in combination with PF may represent a novel therapeutic strategy for GBC. Video abstract.

Synergistic Tumor Inhibition via Energy Elimination by Repurposing Penfluridol and 2-Deoxy-D-Glucose in Lung Cancer

Simple Summary

Drug repurposing has been effective for discovering novel treatments for cancer. The antipsychotic agent penfluridol was reported to suppress lung cancer growth via ATP energy deprivation. The aim of our study was to investigate how penfluridol influences energy metabolism in lung cancer cells. We observed that penfluridol inhibited mitochondrial oxidative phosphorylation (OXPHOS), but induced glycolysis to compensate for the loss of ATP caused by suppression of mitochondrial OXPHOS. We also confirmed that inhibition of glycolysis by 2-deoxy-D-glucose (2DG) significantly augmented the antitumor effects caused by penfluridol in vitro and in vivo. Our studies provide novel insights into repurposing penfluridol combined with 2-DG for lung cancer treatment.

Abstract

Energy metabolism is the basis for cell growth, and cancer cells in particular, are more energy-dependent cells because of rapid cell proliferation. Previously, we found that penfluridol, an antipsychotic drug, has the ability to trigger cell growth inhibition of lung cancer cells via inducing ATP energy deprivation. The toxic effect of penfluridol is related to energy metabolism, but the underlying mechanisms remain unclear. Herein, we discovered that treatment of A549 and HCC827 lung cancer cells with penfluridol caused a decrease in the total amount of ATP, especially in A549 cells. An Agilent Seahorse ATP real-time rate assay revealed that ATP production rates from mitochondrial respiration and glycolysis were, respectively, decreased and increased after penfluridol treatment. Moreover, the amount and membrane integrity of mitochondria decreased, but glycolysis-related proteins increased after penfluridol treatment. Furthermore, we observed that suppression of glycolysis by reducing glucose supplementation or using 2-deoxy-D-glucose (2DG) synergistically enhanced the inhibitory effect of penfluridol on cancer cell growth and the total amount of mitochondria. A mechanistic study showed that the penfluridol-mediated energy reduction was due to inhibition of critical regulators of mitochondrial biogenesis, the sirtuin 1 (SIRT1)/peroxisome-proliferator-activated receptor co-activator-1α (PGC-1α) axis. Upregulation of the SIRT1/PGC-1α axis reversed the inhibitory effect of penfluridol on mitochondrial biogenesis and cell viability. Clinical lung cancer samples revealed a positive correlation between PGC-1α (PPARGC1A) and SIRT1 expression. In an orthotopic lung cancer mouse model, the anticancer activities of penfluridol, including growth and metastasis inhibition, were also enhanced by combined treatment with 2DG. Our study results strongly support that a combination of repurposing penfluridol and a glycolysis inhibitor would be a good strategy for enhancing the anticancer activities of penfluridol in lung cancer.

Targeting DRD2 by the antipsychotic drug, penfluridol, retards growth of renal cell carcinoma via inducing stemness inhibition and autophagy-mediated apoptosis

Renal cell carcinoma (RCC) is one of the most lethal genitourinary malignancies with poor prognoses, since it is largely resistant to chemotherapy, radiotherapy, and targeted therapy. The persistence of cancer stem cells (CSCs) is the major cause of treatment failure with RCC. Recent evidence showed that dopamine receptor D2 (DRD2)-targeting antipsychotic drugs such as penfluridol exert oncostatic effects on several cancer types, but the effect of penfluridol on RCC remains unknown. Here, we uncovered penfluridol suppressed in vitro cell growth and in vivo tumorigenicity of various RCC cell lines (Caki-1, 786-O, A498, and ACHN) and enhanced the Sutent (sunitinib)-triggered growth inhibition on clear cell (cc)RCC cell lines. Mechanistically, upregulation of endoplasmic reticulum (ER) stress-induced unfolded protein response (UPR) was critical for autophagy-mediated apoptosis induced by penfluridol. Transcriptional inhibition of OCT4 and Nanog via inhibiting GLI1 was important for penfluridol-induced stemness and proliferation inhibition. The anticancer activities of penfluridol on ccRCC partially occurred through DRD2. In clinical ccRCC specimens, positive correlations of DRD2 with GLI1, OCT4, and Nanog were observed and their expressions were correlated with worse prognoses. Summarizing, DRD2 antagonists such as penfluridol induce UPR signaling and suppress the GLI1/OCT4/Nanog axis in ccRCC cells to reduce their growth through inducing autophagy-mediated apoptosis and stemness inhibition. These drugs can be repurposed as potential agents to treat ccRCC patients.

Autophagy in cancer: The cornerstone during glutamine deprivation

Over the past two decades, researchers have revealed the crucial functions of glutamine in supporting the hyperproliferation state of cancer cells. Glutamine acts on maintaining high energy production, supporting redox status and amino acid homeostasis. Therefore, cancer cells exhibit excessive uptake of the extracellular glutamine, synthesize it in some cases, and recycle intracellular and extracellular proteins to provide an additional source of glutamine to satisfy the increasing glutamine demand. On the other hand, autophagy's role is still debated regarding tumor initiation and progression. However, most cancer cells urgently need autophagy to overcome the existential threats during glutamine restriction stress. Downstream to various stress pathways induced during such a condition, autophagy is considered an indispensable cytoprotective tool to maintain cell integrity and survival. However, the overactivation of the autophagy process is related to lethal consequences. This review summarized glutamine pathways to control autophagy and highlighted autophagy's primary activation pathways, and discussed the roles during glutamine deprivation.

Repurposing Antipsychotics for Cancer Treatment

Cancer is a leading cause of death worldwide, with approximately 19 million new cases each year. Lately, several novel chemotherapeutic drugs have been introduced, efficiently inhibiting tumor growth and proliferation. However, developing a new drug is a time- and money-consuming process, requiring around 1 billion dollars and nearly ten years, with only a minority of the initially effective anti-cancer drugs experimentally finally being efficient in human clinical trials. Drug repurposing for cancer treatment is an optimal alternative as the safety of these drugs has been previously tested, and thus, in case of successful preclinical studies, can be introduced faster and with a lower cost into phase 3 clinical trials. Antipsychotic drugs are associated with anti-cancer properties and, lately, there has been an increasing interest in their role in cancer treatment. In the present review, we discussed in detail the in-vitro and in-vivo properties of the most common typical and atypical antipsychotics, along with their mechanism of action.

Repurposing drugs in autophagy for the treatment of cancer: From bench to bedside

Autophagy is a multistep degradation pathway involving the lysosome, which supports nutrient reuse and metabolic balance, and has been implicated as a process that regulates cancer genesis and development. Targeting tumors by regulating autophagy has become a therapeutic strategy of interest. Drugs with other indications can have antitumor activity by modulating autophagy, providing a shortcut to developing novel antitumor drugs (i.e., drug repurposing/repositioning), as successfully performed for chloroquine (CQ); an increasing number of repurposed drugs have since advanced into clinical trials. In this review, we describe the application of different drug-repurposing approaches in autophagy for the treatment of cancer and focus on repurposing drugs that target autophagy to treat malignant neoplasms.

Blocking MMP-12-modulated epithelial-mesenchymal transition by repurposing penfluridol restrains lung adenocarcinoma metastasis via uPA/uPAR/TGF-β/Akt pathway

PURPOSE

Metastasis of lung adenocarcinoma (LADC) is a crucial factor determining patient survival. Repurposing of the antipsychotic agent penfluridol has been found to be effective in the inhibition of growth of various cancers. As yet, however, the anti-metastatic effect of penfluridol on LADC has rarely been investigated. Herein, we addressed the therapeutic potential of penfluridol on the invasion/metastasis of LADC cells harboring different epidermal growth factor receptor (EGFR) mutation statuses.

METHODS

MTS viability, transwell migration and invasion, and tumor endothelium adhesion assays were employed to determine cytotoxic and anti-metastatic effects of penfluridol on LADC cells. Protease array, Western blot, immunohistochemistry (IHC), immunofluorescence (IF) staining, and expression knockdown by shRNA or exogenous overexpression by DNA plasmid transfection were performed to explore the underlying mechanisms, both in vitro and in vivo.

RESULTS

We found that nontoxic concentrations of penfluridol reduced the migration, invasion and adhesion of LADC cells. Protease array screening identified matrix metalloproteinase-12 (MMP-12) as a potential target of penfluridol to modulate the motility and adhesion of LADC cells. In addition, we found that MMP-12 exhibited the most significantly adverse prognostic effect in LADC among 39 cancer types. Mechanistic investigations revealed that penfluridol inhibited the urokinase plasminogen activator (uPA)/uPA receptor/transforming growth factor-β/Akt axis to downregulate MMP-12 expression and, subsequently, reverse MMP-12-induced epithelial-mesenchymal transition (EMT). Subsequent analysis of clinical LADC samples revealed a positive correlation between MMP12 and mesenchymal-related gene expression levels. A lower survival rate was found in LADC patients with a SNAl1high/MMP12high profile compared to those with a SNAl1low/MMP12low profile.

CONCLUSIONS

Our results indicate that MMP-12 may serve as a useful biomarker for predicting LADC progression and as a promising penfluridol target for treating metastatic LADC.

Octyl syringate is preferentially cytotoxic to cancer cells via lysosomal membrane permeabilization and autophagic flux inhibition

The autophagy-mediated lysosomal pathway plays an important role in conferring stress tolerance to tumor cells during cellular stress such as increased metabolic demands. Thus, targeted disruption of this function and inducing lysosomal cell death have been proved to be a useful cancer therapeutic approach. In this study, we reported that octyl syringate (OS), a novel phenolic derivate, was preferentially cytotoxic to various cancer cells but was significantly less cytotoxic to non-transformed cells. Treatment with OS resulted in non-apoptotic cell death in a caspase-independent manner. Notably, OS not only enhanced accumulation of autophagic substrates, including lapidated LC3 and sequestosome-1, but also inhibited their degradation via an autophagic flux. In addition, OS destabilized the lysosomal function, followed by the intracellular accumulation of the non-digestive autophagic substrates such as bovine serum albumin and stress granules. Furthermore, OS triggered the release of lysosomal enzymes into the cytoplasm that contributed to OS-induced non-apoptotic cell death. Finally, we demonstrated that OS was well tolerated and reduced tumor growth in mouse xenograft models. Taken together, our study identifies OS as a novel anticancer agent that induces lysosomal destabilization and subsequently inhibits autophagic flux and further supports development of OS as a lysosome-targeting compound in cancer therapy. • Octyl syringate, a phenolic derivate, is preferentially cytotoxic to various cancer cells. • Octyl syringate destabilizes the lysosomal function. • Octyl syringate blocks the autophagic flux. • Octyl syringate is a potential candidate compound for cancer therapy.

Penfluridol as a Candidate of Drug Repurposing for Anticancer Agent

Penfluridol has robust antipsychotic efficacy and is a first-generation diphenylbutylpiperidine. Its effects last for several days after a single oral dose and it can be administered once a week to provide better compliance and symptom control. Recently; strong antitumour effects for penfluridol were discovered in various cancer cell lines; such as breast; pancreatic; glioblastoma; and lung cancer cells via several distinct mechanisms. Therefore; penfluridol has drawn much attention as a potentially novel anti-tumour agent. In addition; the anti-cancer effects of penfluridol have been demonstrated in vivo: results showed slight changes in the volume and weight of organs at doses tested in animals. This paper outlines the potential for penfluridol to be developed as a next-generation anticancer drug.