Cannabigerol Induces Autophagic Cell Death by Inhibiting EGFR-RAS Pathways in Human Pancreatic Ductal Adenocarcinoma Cell Lines.

Pancreatic ductal adenocarcinoma (PDAC) is the most frequent infiltrating type of pancreatic cancer. The poor prognosis associated with this cancer is due to the absence of specific biomarkers, aggressiveness, and treatment resistance. PDAC is a deadly malignancy bearing distinct genetic alterations, the most common being those that result in cancer-causing versions of the KRAS gene. Cannabigerol (CBG) is a non-psychomimetic cannabinoid with anti-inflammatory properties. Regarding the anticancer effect of CBG, up to now, there is only limited evidence in human cancers. To fill this gap, we investigated the effects of CBG on the PDAC cell lines, PANC-1 and MIAPaCa-2. The effect of CBG activity on cell viability, cell death, and EGFR-RAS-associated signaling was investigated. Moreover, the potential synergistic effect of CBG in combination with gemcitabine (GEM) and paclitaxel (PTX) was investigated. MTT was applied to investigate the effect of CBG on PDAC cell line viabilities. Annexin-V and Acridine orange staining, followed by cytofluorimetric analysis and Western blotting, were used to evaluate CBG's effect on cell death. The modulation of EGFR-RAS-associated pathways was determined by Western blot analysis and a Milliplex multiplex assay. Moreover, by employing the MTT data and SynergyFinder Plus software analysis, the effect of the combination of CBG and chemotherapeutic drugs was determined.

Hernandezine induces autophagic cell death in human pancreatic cancer cells via activation of the ROS/AMPK signaling pathway.

Hernandezine (Her) is a bisbenzylisoquinoline alkaloid extracted from the traditional Chinese herbal medicine Thalictrum glandulosissimum. Evidence shows that Her is a natural agonist of adenosine monophosphate (AMP)-activated protein kinase (AMPK) and induces apoptosis and autophagy in tumor cells. In this study, we investigated the role of autophagy in Her-induced cell death in human pancreatic cancer cell lines. We showed that Her dose-dependently suppressed cell proliferation, promoted autophagy and induced autophagic death in pancreatic ductal adenocarcinoma (PDAC) cell lines Capan-1 and SW1990. The IC50 values of Her in inhibition of Capan-1 and SW1990 cells were 47.7 µM and 40.1 µM, respectively. Immunoblotting showed that Her (1-40 µM) promoted the conversion of LC3-I to LC3-II, and Her exerted concentration-dependent and time-dependent effects on autophagy activation in PDAC cells. In transmission electron microscopy and fluorescence image analysis, we found that autophagic vacuoles were significantly increased in Her-treated cells. Knockdown of ATG5, a key gene in the autophagy pathway, alleviated the activation of autophagy by Her. These results demonstrated that Her induced autophagy in PDAC cells. Intensely activated autophagy could promote cell death. The autophagy inhibitors, BafA1 and HCQ significantly inhibited Her-induced cell death, implying that Her induced autophagic cell death in PDAC cells. Moreover, we showed that Her activated autophagy by increasing the phosphorylation of AMPK and decreasing the phosphorylation of mTOR/p70S6K. Knockdown of AMPKα relieves the autophagic cell death induced by Her. Furthermore, Her concentration-dependently enhanced reactive oxygen species (ROS) generation in PDAC cells. Antioxidants could reduce the phosphorylation of AMPK and suppress autophagic cell death induced by Her. Our study provides evidence for the development of Her as a therapeutic agent for the treatment of pancreatic cancer.

Mallotucin D, a Clerodane Diterpenoid from Croton crassifolius, Suppresses HepG2 Cell Growth via Inducing Autophagic Cell Death and Pyroptosis.

Hepatocellular carcinoma (HCC) is a major subtype of primary liver cancer with a high mortality rate. Pyroptosis and autophagy are crucial processes in the pathophysiology of HCC. Searching for efficient drugs targeting pyroptosis and autophagy with lower toxicity is useful for HCC treatment. Mallotucin D (MLD), a clerodane diterpenoid from Croton crassifolius, has not been previously reported for its anticancer effects in HCC. This study aims to evaluate the inhibitory effects of MLD in HCC and explore the underlying mechanism. We found that the cell proliferation, DNA synthesis, and colony formation of HepG2 cells and the angiogenesis of HUVECs were all greatly inhibited by MLD. MLD caused mitochondrial damage and decreased the TOM20 expression and mitochondrial membrane potential, inducing ROS overproduction. Moreover, MLD promoted the cytochrome C from mitochondria into cytoplasm, leading to cleavage of caspase-9 and caspase-3 inducing GSDMD-related pyroptosis. In addition, we revealed that MLD activated mitophagy by inhibiting the PI3K/AKT/mTOR pathway. Using the ROS-scavenging reagent NAC, the activation effects of MLD on pyroptosis- and autophagy-related pathways were all inhibited. In the HepG2 xenograft model, MLD effectively inhibited tumor growth without detectable toxicities in normal tissue. In conclusion, MLD could be developed as a candidate drug for HCC treatment by inducing mitophagy and pyroptosis via promoting mitochondrial-related ROS production.

Adenosine derivatives from Cordyceps exert antitumor effects against ovarian cancer cells through ENT1-mediated transport, induction of AMPK signaling, and consequent autophagic cell death.

Cordyceps militaris is rich in adenosine derivatives, including 3'-deoxyadenosine, also known as cordycepin. It has been reported for antitumor effects, but its underlying molecular mechanism has yet to be elucidated. We investigated how adenosine derivatives exerted antitumor effects against ovarian cancer using human ovarian cancer cells and a xenograft mouse model. Treatment with adenosine derivatives effectively resulted in cell death of ovarian cancer cells through AMPK activation and subsequently mTOR-mediated autophagic induction. Intriguingly, the effect required membrane transport of adenosine derivatives via ENT1, rather than ADORA-mediated cellular signaling. Our data suggest that adenosine derivatives may be an effective therapeutic intervention in ovarian cancer through induction of ENT1-AMPK-mTOR-mediated autophagic cell death.

Targeting Regulated Cell Death with Pharmacological Small Molecules: An Update on Autophagy-Dependent Cell Death, Ferroptosis, and Necroptosis in Cancer.

Regulated cell death is a widely attractive subject among the topics of cancer therapy and has gained some advances for discovery of targeted anticancer drugs. In the past decade, nonapoptotic regulated cell death has been implicated in the development and therapeutic responses of a variety of human cancers. Hitherto, targeting autophagy-dependent cell death (ADCD), ferroptosis, and necroptosis with small molecules has been emerging as a hopeful strategy for the improvement of potential cancer therapy, which may have an advantage to bypass the apoptosis-resistance machinery. Thus, in this perspective, we concentrate on the key molecular insights into ADCD, ferroptosis, and necroptosis and summarize the corresponding small molecules in potential cancer therapy. Moreover, the relationships between the three subroutines and small molecules modulating the crosstalk are discussed. We believe that these inspiring findings would be advantageous to exploiting more potential targets and pharmacological small molecules in future cancer treatment.

Exosomes derived from calcium oxalate-treated macrophages promote apoptosis of HK-2 cells by promoting autophagy.

Calcium oxalate (CaOx) crystals are the main component of kidney stones. Macrophages have the function of eliminating these crystals, and the underlying mechanism remains unclear. Here, we attempted to determine the role of macrophage-derived exosomes exposed to CaOx crystals in regulating apoptosis of human proximal tubular cells (HK-2). Exosomes (CaOx-Exo) were isolated from CaOx-treated macrophages and then incubated with HK-2 cells. CaOx-Exo treatment reduced cell viability and promoted apoptosis of HK-2 cells. The expression of Caspase-3 and Bax was increased, and Bcl-2 expression was decreased in HK-2 cells following CaOx-Exo treatment. Moreover, CaOx-Exo treatment caused an increase of LC3-II/LC3-I ratio and Beclin-1 expression and a downregulation of p62 in HK-2 cells. GFP-LC3 puncta were increased in HK-2 cells following CaOx-Exo treatment. Additionally, CaOx-Exo-treated HK-2 cells were treated with 3-methyladenine (3-MA) to inhibit autophagy activity. 3-MA treatment weakened the impact of CaOx-Exo on cell viability and apoptosis of HK-2 cells. 3-MA treatment also reduced the LC3-II/LC3-I ratio and Beclin-1 expression and enhanced p62 expression in CaOx-Exo-treated HK-2 cells. In conclusion, these data demonstrated that exosomes derived from CaOx-treated macrophages promote apoptosis of HK-2 cells by promoting autophagy. Thus, this work suggests that macrophage-derived exosomes may play a vital role in CaOx-induced human proximal tubular cell damage.

Curcumin induces autophagic cell death in human thyroid cancer cells.

Curcumin, a polyphenolic compound, is a well-known anticancer agent, although its poor bioavailability remains a big concern. Recent studies suggest that autophagy-targeted therapy may be a useful adjunct treatment for patients with thyroid cancer. Curcumin acts as an autophagy inducer on many cancer cells. However, little is known about the exact role of curcumin on thyroid cancer cells. In the present study, curcumin significantly inhibited the growth of thyroid cancer cells. Autophagy was markedly induced by curcumin treatment as evidenced by an increase in LC3-II conversion, beclin-1 accumulation, p62 degradation as well as the increased formation of acidic vesicular organelles (AVOs). 3-MA, an autophagy inhibitor, partially rescued thyroid cancer cells from curcumin-induced cell death. Additionally, curcumin was found to exert selective cytotoxicity on thyroid cancer cells but not normal epithelial cells and acted as an autophagy inducer through activation of MAPK while inhibition of mTOR pathways. Hyperactivation of the AKT/mTOR axis was observed in the majority of PTC samples we tested, and thyroid cancer cell lines along with cancer tissue specimens sustained a low basal autophagic activity. Taken together, our results provide new evidence that inducing autophagic cell death may serve as a potential anti-cancer strategy to handle thyroid cancer.

Rapalogs induce non-apoptotic, autophagy-dependent cell death in HPV-negative TP53 mutant head and neck squamous cell carcinoma.

TP53 is the most frequently mutated gene in head and neck squamous cell carcinoma (HNSCC). Patients with HPV-negative TP53 mutant HNSCC have the worst prognosis, necessitating additional agents for treatment. Since mutant p53 causes sustained activation of the PI3K/AKT/mTOR signaling pathway, we investigated the effect of rapalogs RAD001 and CCI-779 on HPV-negative mutTP53 HNSCC cell lines and xenografts. Rapalogs significantly reduced cell viability and colony formation. Interestingly, rapalogs-induced autophagy with no effect on apoptosis. Pretreatment with autophagy inhibitors, 3-methyladenine (3-MA) and ULK-101 rescued the cell viability by inhibiting rapalog-induced autophagy, suggesting that both RAD001 and CCI-779 induce non-apoptotic autophagy-dependent cell death (ADCD). Moreover, rapalogs upregulated the levels of ULK1 and pULK1 S555 with concomitant downregulation of the mTORC1 pathway. However, pretreatment of cells with rapalogs prevented the ULK-101-mediated inhibition of ULK1 to sustained autophagy, suggesting that rapalogs induce ADCD through the activation of ULK1. To further translate our in vitro studies, we investigated the effect of RAD001 in HPV-negative mutTP53 (HN31 and FaDu) tumor cell xenograft model in nude mice. Mice treated with RAD001 exhibited a significant tumor volume reduction without induction of apoptosis, and with a concomitant increase in autophagy. Further, treatment with RAD001 was associated with a considerable increase in pULK1 S555 and ULK1 levels through the inhibition of mTORC1. 3-MA reversed the effect of RAD001 on FaDu tumor growth suggesting that RAD001 promotes ACDC in HPV-negative mutTP53 xenograft. This is the first report demonstrating that rapalogs promote non-apoptotic ADCD in HPV-negative mutTP53 HNSCC via the ULK1 pathway. Further studies are required to establish the promising role of rapalogs in preventing the regrowth of HPV-negative mutTP53 HNSCC.

Vorinostat in autophagic cell death: A critical insight into autophagy-mediated, -associated and -dependent cell death for cancer prevention.

Histone deacetylases (HDACs) inhibit the acetylation of crucial autophagy genes, thereby deregulating autophagy and autophagic cell death (ACD) and facilitating cancer cell survival. Vorinostat, a broad-spectrum pan-HDAC inhibitor, inhibits the deacetylation of key autophagic markers and thus interferes with ACD. Vorinostat-regulated ACD can have an autophagy-mediated, -associated or -dependent mechanism depending on the involvement of apoptosis. Molecular insights revealed that hyperactivation of the PIK3C3/VPS34-BECN1 complex increases lysosomal disparity and enhances mitophagy. These changes are followed by reduced mitochondrial biogenesis and by secondary signals that enable superactivated, nonselective or bulk autophagy, leading to ACD. Although the evidence is limited, this review focuses on molecular insights into vorinostat-regulated ACD and describes critical concepts for clinical translation.

Cinnamaldehyde induces autophagy-mediated cell death through ER stress and epigenetic modification in gastric cancer cells.

Previous reports suggested that cinnamaldehyde (CA), the bioactive ingredient in Cinnamomum cassia, can suppress tumor growth, migratory, and invasive abilities. However, the role and molecular mechanisms of CA in GC are not completely understood. In the present study, we found that CA-induced ER stress and cell death via the PERK-CHOP axis and Ca2+ release in GC cells. Inhibition of ER stress using specific-siRNA blocked CA-induced cell death. Interestingly, CA treatment resulted in autophagic cell death by inducing Beclin-1, ATG5, and LC3B expression and by inhibiting p62 expression whereas autophagy inhibition suppressed CA-induced cell death. We showed that CA induces the inhibition of G9a and the activation of LC3B. Moreover, CA inhibited G9a binding on Beclin-1 and LC3B promoter. Overall, these results suggested that CA regulates the PERK-CHOP signaling, and G9a inhibition activates autophagic cell death via ER stress in GC cells.

Biotinylated curcumin as a novel chemosensitizer enhances naphthalimide-induced autophagic cell death in breast cancer cells.

Achieving selective release of chemical anticancer agents and improving therapeutic efficacy has always been a hot spot in the field of cancer research, yet how to achieve this remains a great challenge. In this work, we constructed a novel chemical anticancer agent (named MCLOP) by introducing naphthalimide into the skeleton of methylene blue (MB). Under the stimulation by cellular hypochlorous acid (HClO) and visible light, selective release of active naphthalimide can be achieved within breast cancer cell lines, the release process of which can be tracked visually using near-infrared fluorescence of MB (685 nm). More importantly, we developed biotinylated curcumin (Cur-Bio) as a new chemosensitizer, which significantly enhanced the ability of MCLOP to induce autophagic cell death of breast cancer cells. This synergistic treatment strategy exhibited an excellent anti-proliferation effect on breast cancer cells in vitro, three-dimensional (3D) cell sphere model, and mouse tumor model in vivo. This work provides a new strategy for the treatment of breast cancer and also opens new opportunities for the efficient treatment of cancer with curcumin-based chemosensitizer.

Ivermectin accelerates autophagic death of glioma cells by inhibiting glycolysis through blocking GLUT4 mediated JAK/STAT signaling pathway activation.

OBJECTIVE: This study aimed to investigate the regulatory effect of ivermectin (IVM) on energy metabolism in glioma progression, and provide a reference for the treatment of glioma. METHODS: Glioma cells were treated with IVM to measure cell viability, autophagy marker protein expression, ATP content, glucose uptake, pyruvate content, and expression of key enzymes of glycolysis. Glucose transporter 4 (GLUT4) or siGLUT4 was transfected in IVM treated U87 cells to investigate the effect of GLUT4 on cellular glycolysis and autophagy. The JAK2 inhibitor AZD-1480 was introduced to explore the specific mechanism by which IVM regulates glycolysis and autophagy. Rat models of glioma xenograft were constructed and treated with 10 mg/kg IVM to observe tumor growth and examine the expression levels of GLUT4 and autophagy marker proteins in tumor tissues. RESULTS: IVM inhibited glioma cell survival and promoted cell death. IVM promoted LC3-II protein expression and inhibited p62/SQSTM1 protein expression in glioma cells. IVM decreased adenosine-triphosphate (ATP) and pyruvate content, promoted glucose uptake, and reduced HK2 and PFK1 protein expression in U87 cells. IVM inhibited GLUT4 protein expression, and overexpression of GLUT4 promoted glycolysis and inhibited autophagic cell death in U87 cells. IVM inhibited glycolysis by blocking GLUT4 mediated the Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway activation. IVM inhibited tumor growth in vivo, decreased the protein expression of GLUT4, JAK2, HK2, and PFK1 in tumor tissues, decreased the phosphorylation levels of STAT3/STAT5, and promoted the expression of autophagy marker proteins. CONCLUSIONS: IVM accelerates autophagic death of glioma cells by inhibiting glycolysis through blocking GLUT4 mediated JAK/STAT signaling pathway activation.

Suppression of DYRK1A/B Drives Endoplasmic Reticulum Stress-mediated Autophagic Cell Death Through Metabolic Reprogramming in Colorectal Cancer Cells.

BACKGROUND/AIM: We previously identified KS40008 (4-(3-(4-hydroxyphenyl)-1H-pyrazolo[3,4-b]pyridin-5-yl)benzene-1,2-diol), a novel inhibitor of dual-specificity tyrosine phosphorylation-regulated kinase family (DYRK) 1A/B, which exhibited high enzymatic activity and cell proliferation-inhibitory effects in colorectal cancer (CRC) cell lines. In the present study, we aimed to elucidate the antitumor mechanisms of KS40008. MATERIALS AND METHODS: To assess the cytotoxicity of KS40008, we utilized a human cell line and organoid model and performed a CCK-8 assay and real-time cell analysis. Mitochondrial function was determined through mitochondrial staining, mito-stress test, and glycolysis test. In addition, we investigated the mechanisms of cancer cell death induced by KS40008 through immunoblotting, real-time quantitative polymerase chain reaction, reactive oxygen species staining, and immunofluorescence staining. RESULTS: KS40008 exhibited significant cytotoxicity in CRC and non-CRC cell lines, and organoid models compared to 5-fluorouracil, a conventional chemotherapeutic drug. Moreover, KS40008-induced inhibition of DYRK1A/B led to mitochondrial dysfunction and endoplasmic reticulum stress, promoting autophagic cancer cell death. CONCLUSION: KS40008 exerts antitumor activity through the inhibition of DYRK1A/B. Here, we demonstrated a mechanism by which KS40008 affects endoplasmic reticulum stress-mediated autophagy through the induction of mitochondrial stress, leading to cytotoxicity in CRC.

Apigenin Induces Autophagy and Cell Death by Targeting EZH2 under Hypoxia Conditions in Gastric Cancer Cells.

Hypoxia is a major obstacle to gastric cancer (GC) therapy and leads to chemoresistance as GC cells are frequently exposed to the hypoxia environment. Apigenin, a flavonoid found in traditional medicine, fruits, and vegetables and an HDAC inhibitor, is a powerful anti-cancer agent against various cancer cell lines. However, detailed mechanisms involved in the treatment of GC using APG are not fully understood. In this study, we investigated the biological activity of and molecular mechanisms involved in APG-mediated treatment of GC under hypoxia. APG promoted autophagic cell death by increasing ATG5, LC3-II, and phosphorylation of AMPK and ULK1 and down-regulating p-mTOR and p62 in GC. Furthermore, our results show that APG induces autophagic cell death via the activation of the PERK signaling, indicating an endoplasmic reticulum (ER) stress response. The inhibition of ER stress suppressed APG-induced autophagy and conferred prolonged cell survival, indicating autophagic cell death. We further show that APG induces ER stress- and autophagy-related cell death through the inhibition of HIF-1α and Ezh2 under normoxia and hypoxia. Taken together, our findings indicate that APG activates autophagic cell death by inhibiting HIF-1α and Ezh2 under hypoxia conditions in GC cells.

Transcriptomic Profiling Reveals AKR1C1 and AKR1C3 Mediate Cisplatin Resistance in Signet Ring Cell Gastric Carcinoma via Autophagic Cell Death.

Signet ring cell gastric carcinoma (SRCGC) is a lethal malignancy that has developed drug resistance to cisplatin therapies. The aim of this study was to characterize the acquisition of the cisplatin-resistance SRCGC cell line (KATO/DDP cells) and to understand the molecular mechanisms underlying cisplatin resistance. Transcriptomic and bioinformatic analyses were used to identify the candidate gene. This was confirmed by qPCR and Western blot. Aldoketoreductase1C1 and 1C3 (AKR1C1 and AKR1C3) were the most promising molecules in KATO/DDP cells. A specific inhibitor of AKR1C1 (5PBSA) and AKR1C3 (ASP9521) was used to enhance cisplatin-induced KATO/DPP cell death. Although cisplatin alone induced KATO/DDP apoptosis, a combination treatment of cisplatin and the AKR1C inhibitors had no influence on percent cell apoptosis. In conjunction with the autophagy inhibitor, 3MA, attenuated the effects of 5PBSA or ASP9521 to enhance cisplatin-induced cell death. These results indicated that AKR1C1 and 1C3 regulated cisplatin-induced KATO/DDP cell death via autophagy. Moreover, cisplatin in combination with AKR1C inhibitors and N-acetyl cysteine increased KATO/DDP cells' viability when compared with a combination treatment of cisplatin and the inhibitors. Taken together, our results suggested that AKR1C1 and 1C3 play a crucial role in cisplatin resistance of SRCGC by regulating redox-dependent autophagy.

BHLHE41/DEC2 Expression Induces Autophagic Cell Death in Lung Cancer Cells and Is Associated with Favorable Prognosis for Patients with Lung Adenocarcinoma.

Lung cancer constitutes a threat to human health. BHLHE41 plays important roles in circadian rhythm and cell differentiation as a negative regulatory transcription factor. This study investigates the role of BHLHE41 in lung cancer progression. We analyzed BHLHE41 function via in silico and immunohistochemical studies of 177 surgically resected non-small cell lung cancer (NSCLC) samples and 18 early lung squamous cell carcinoma (LUSC) cases. We also examined doxycycline (DOX)-inducible BHLHE41-expressing A549 and H2030 adenocarcinoma cells. BHLHE41 expression was higher in normal lung than in lung adenocarcinoma (LUAD) tissues and was associated with better prognosis for the overall survival (OS) of patients. In total, 15 of 132 LUAD tissues expressed BHLHE41 in normal lung epithelial cells. Staining was mainly observed in adenocarcinoma in situ and the lepidic growth part of invasive cancer tissue. BHLHE41 expression constituted a favorable prognostic factor for OS (p = 0.049) and cause-specific survival (p = 0.042) in patients with LUAD. During early LUSC, 7 of 18 cases expressed BHLHE41, and this expression was inversely correlated with the depth of invasion. DOX suppressed cell proliferation and increased the autophagy protein LC3, while chloroquine enhanced LC3 accumulation and suppressed cell death. In a xenograft model, DOX suppressed tumor growth. Our results indicate that BHLHE41 expression prevents early lung tumor malignant progression by inducing autophagic cell death in NSCLC.

Reactive Oxygen Species Mediate 6c-Induced Mitochondrial and Lysosomal Dysfunction, Autophagic Cell Death, and DNA Damage in Hepatocellular Carcinoma.

Increasing the level of reactive oxygen species (ROS) in cancer cells has been suggested as a viable approach to cancer therapy. Our previous study has demonstrated that mitochondria-targeted flavone-naphthalimide-polyamine conjugate 6c elevates the level of ROS in cancer cells. However, the detailed role of ROS in 6c-treated cancer cells is not clearly stated. The biological effects and in-depth mechanisms of 6c in cancer cells need to be further investigated. In this study, we confirmed that mitochondria are the main source of 6c-induced ROS, as demonstrated by an increase in 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) and MitoSox fluorescence. Compound 6c-induced mitochondrial ROS caused mitochondrial dysfunction and lysosomal destabilization confirmed by absolute quantitation (iTRAQ)-based comparative proteomics. Compound 6c-induced metabolic pathway dysfunction and lysosomal destabilization was attenuated by N-acetyl-L-cysteine (NAC). iTRAQ-based comparative proteomics showed that ROS regulated the expression of 6c-mediated proteins, and treatment with 6c promoted the formation of autophagosomes depending on ROS. Compound 6c-induced DNA damage was characterized by comet assay, p53 phosphorylation, and γH2A.X, which was diminished by pretreatment with NAC. Compound 6c-induced cell death was partially reversed by 3-methyladenine (3-MA), bafilomycin (BAF) A1, and NAC, respectively. Taken together, the data obtained in our study highlighted the involvement of mitochondrial ROS in 6c-induced autophagic cell death, mitochondrial and lysosomal dysfunction, and DNA damage.

Autophagy-Dependent Apoptosis Induced by Apoferritin-Cu(II) Nanoparticles in Multidrug-Resistant Colon Cancer Cells.

Chemotherapy continues to be the most commonly applied strategy for cancer. Despite the impressive clinical success obtained with several drugs, increasing numbers of (multi)drug-resistant tumors are reported. To overcome this shortcoming, novel drug candidates and delivery systems are urgently needed. Herein, a therapeutic copper polypyridine complex encapsulated in natural nanocarrier apoferritin is reported. The generated nanoparticles showed higher cytotoxicity toward various (drug-resistant) cancer cell lines than noncancerous cells. The study of the mechanism revealed that the compound triggers cell autophagy-dependent apoptosis. Promisingly, upon injection of the nanodrug conjugate into the bloodstream of a mouse model bearing a multidrug-resistant colon tumor, a strong tumor growth inhibition effect was observed. To date, this is the first study describing the encapsulation of a copper complex in apoferritin that acts by autophagy-dependent apoptosis.

Lycopene prevents oxygen-glucose deprivation-induced autophagic death in SH-SY5Y cells via inhibition of the oxidative stress-activated AMPK/mTOR pathway.

Lycopene has been reported to exert a protective effect on the brain against transient ischemia­induced damage; however, whether it could regulate autophagic neuronal death remains elusive. The present study aimed to investigate the role of autophagy in the protective effects of lycopene against neuronal damage and its underlying mechanism. Oxygen­glucose deprivation (OGD) was used to simulate neuronal ischemic injury in human SH­SY5Y cells. Lactate dehydrogenase (LDH) release assay revealed that OGD induced SH­SY5Y cell death. Western blotting demonstrated that OGD upregulated the expression levels of the autophagy marker proteins autophagy protein 5 (ATG5) and LC3II, but downregulated the autophagy substrate p62 in a time­dependent manner. By contrast, OGD­induced cell death was significantly inhibited by the autophagy inhibitors 3­methyladenine or bafilomycin A1 or by knockdown of ATG5, indicating that OGD may induce autophagic death in SH­SY5Y cells. Notably, lycopene was shown not only to prevent OGD­induced SH­SY5Y cell death, but was also able to effectively inhibit OGD­induced upregulation of ATG5 and LC3II, and downregulation of p62 in a dose­dependent manner. Mechanistically, it was suggested that lycopene inhibited OGD­induced activation of the AMPK/mTOR pathway via attenuation of oxidative stress by maintaining the intracellular antioxidant glutathione (GSH). Furthermore, the inhibitory role of lycopene in GSH depletion was found to be associated with the prevention of OGD­induced depletion of intracellular cysteine and downregulation of xCT. Collectively, the present study demonstrated that lycopene protected SH­SY5Y cells against OGD­induced autophagic death by inhibiting oxidative stress­dependent activation of the AMPK/mTOR pathway.

The Sonic Hedgehog signaling pathway regulates autophagy and migration in ovarian cancer.

BACKGROUND: The Sonic Hedgehog (SHH) signaling pathway plays an important role in various types of human cancers including ovarian cancer; however, its function and underlying mechanism in ovarian cancer are still not entirely understood. METHODS: We detected the expressions of SHH and SQSTM1 in borderline ovarian tumor tissues, epithelial ovarian cancer (EOC) tissues and benign ovarian tumor tissues. Cyclopamine (Cyp, a well-known inhibitor of SHH signaling pathway) and chloroquine (CQ, the pharmaceutical inhibitor of autophagy) were used in vivo and in vitro (autophagic flux, CCK-8 assay, wound healing assay, transwell assay, tumor xenograft model). The mechanism of action was explored through Quantitative RT-PCR and Western Blot. RESULTS: We found up-regulation of SHH and accumulation of SQSTM1/P62 in epithelial ovarian cancer. Cyp induced autophagy through the PI3K/AKT signaling pathway. Moreover, low-dose Cyp and chloroquine (CQ) significantly promoted the migratory ability of SKOV3 cells. CONCLUSIONS: Our findings suggest that inhibition of the SHH pathway and autophagy may be a potential and effective therapy for the treatment of ovarian cancer.