Formation Of Acidic Vesicular Organelles Research Articles

Antitumor effects of co-treatment of resveratrol with antitumor drugs in ER- and HER2-positive breast cancer cells are due to induction of apoptosis and modulation of estrogen receptor expression.

Resveratrol, a natural compound, may be an alternative to improving conventional breast cancer therapy. Thus, we assessed the capability of resveratrol at a low dose to enhance the in vitro effect of conventional theray in estrogen receptor (ER) and human epidermal growth factor receptor type 2 (HER2)-positive breast cancer cells. Cell viability of breast cancer cells was measured with neutral red uptake assay. Apoptosis, autophagy, cell cycle progression and cell proliferation were detected through hypotonic fluorescent solution assay, formation of acidic vesicular organelles, flow cytometry, and bromodeoxyuridine assay, respectively. Western blotting was performed to study the expression of pro-apoptotic, anti-apoptotic and autophagic proteins, and estrogen receptors. Resveratrol combined with tamoxifen metabolites or trastuzumab reduced cell viability of ER- and HER2-positive breast cancer cells, respectively. This effect was mainly associated with induction of apoptosis due to a greater formation of hypodiploid nuclei, reduced protein expression of procaspase-7, Bcl-2, Bcl-xL, and PARP; and increased expression of cleaved PARP. Resveratrol decreased the expression of ERα and increased that of ERβ, contributing to the reduced viability on breast cancer cells. Combined treatments induced autophagy, evidenced by increased levels of acidic vesicular organelles and degradation of p62/SQSTM1 protein. Nevertheless, on inhibiting autophagy with 3-methyladenine, cell viability was further reduced and apoptosis was induced, suggesting a pro-survival role of autophagy, impairing apoptosis. Resveratrol increasead the in vitro cytotoxic effect of conventional therapy in breast cancer cells. However, it was necessary to block resveratrol-induced autophagy to improve the therapeutic response.

In vitro and in vivo protective potential of quercetin-3-glucuronide against lipopolysaccharide-induced pulmonary injury through dual activation of nuclear factor-erythroid 2 related factor 2 and autophagy.

In vitro and in vivo models of lipopolysaccharide (LPS)-induced pulmonary injury, quercetin-3-glucuronide (Q3G) has been previously revealed the lung-protective potential via downregulation of inflammation, pyroptotic, and apoptotic cell death. However, the upstream signals mediating anti-pulmonary injury of Q3G have not yet been clarified. It has been reportedthat concerted dual activation of nuclear factor-erythroid 2 related factor 2 (Nrf2) and autophagy may prove to be a better treatment strategy in pulmonary injury. In this study, the effect of Q3G on antioxidant and autophagy were further investigated. Noncytotoxic doses of Q3G abolished the LPS-caused cell injury, and reactive oxygen species (ROS) generation with inductions in Nrf2-antioxidant signaling. Moreover, Q3G treatment repressed Nrf2 ubiquitination, and enhanced the association of Keap1 and p62 in the LPS-treated cells. Q3G also showed potential in inducing autophagy, as demonstrated by formation of acidic vesicular organelles (AVOs) and upregulation of autophagy factors. Next, the autolysosomes formation and cell survival were decreased by Q3G under pre-treatment with a lysosome inhibitor, chloroquine (CQ). Furthermore, mechanistic assays indicated that anti-pulmonary injury effects of Q3G might be mediated via Nrf2 signaling, as confirmed by the transfection of Nrf2 siRNA. Finally, Q3G significantly alleviated the development of pulmonary injury in vivo, which may result from inhibiting the LPS-induced lung dysfunction and edema. These findings emphasize a toxicological perspective, providing new insights into the mechanisms of Q3G's protective effects on LPS-induced pulmonary injury and highlighting its role in dual activating Nrf2 and autophagy pathways.

Ethanolic extract from leaves of tithonia diversifolia induces apoptosis in HCT-116 cells through oxidative stress

ABSTRACT Tithonia diversifolia is a perennial bushy plant found in South America with significant ethnopharmacological importance as an antimalarial, antidiabetic, antibacterial, and anticancer agent. The aim of the present study was to determine the cytotoxicity of the ethanolic extract from leaves of T. diversifolia (TdE) on human cancer cell lines (HCT-116, SNB-19, NCIH-460 and MCF-7), as well as the mechanism of action involved in cell death and cellular modulation of oxidative stress. The TdE exhibited significant activity with IC50 values ranging from 7.12 to 38.41 μg/ml, with HCT-116 being the most sensitive cell line. Subsequent experiments were conducted with HCT-116 cell line. TdE decreased the number of viable cells, followed by induction of apoptotic events, increase in mitochondrial membrane permeabilization, and enhanced G2/M phase of the cell cycle. Pro-oxidative effects including elevated acidic vesicular organelle formation, lipid peroxidation, and nitric oxide by-products, as well as reduced levels of intracellular glutathione and reactive oxygen species production were also observed following incubation with TdE, which may lead to DNA damage followed by apoptotic cell death. These results demonstrate the potential of TdE ethanolic leaf extraction for biological activity and enhance the importance of continuing to study natural sources of plants for the development of anticancer agents.

The modulatory effect of Lactobacillus gasseri ATCC 33323 on autophagy induced by extracellular vesicles of Helicobacter pylori in gastric epithelial cells in vitro

Helicobacter pylori has been recognized as a true pathogen, which is associated with various gastroduodenal diseases, and gastric adenocarcinoma. The crosstalk between H. pylori virulence factors and host autophagy remains challenging. H. pylori can produce extracellular vesicles (EVs) that contribute to gastric inflammation and malignancy. Some probiotic strains have been documented to modulate cell autophagy process. This study was aimed to investigate the modulatory effect of cell-free supernatant (CFS) obtained from Lactobacillus gasseri ATCC 33323 on autophagy induced by H. pylori-derived EVs. EVs were isolated from two clinical H. pylori strains (BY-1 and OC824), and characterized using transmission electron microscopy (TEM) and dynamic light scattering (DLS). The viability of AGS cells was assessed after exposure to different concentrations of H. pylori EVs, and L. gasseri CFS. Based on MTT assay and Annexin V-FITC/PI staining, 50 μg/ml of H. pylori EVs and 10 % v/v of L. gasseri CFS were used for further cell treatment experiments. Autophagy was examined using acridin orange (AO) staining, RT-qPCR analysis for autophagy mediators (LC3B, ATG5, ATG12, ATG16L1, BECN1, MTOR, and NOD1), and western blotting for LC3B expression. H. pylori EVs were detected to range in size from 50 to 200 nm. EVs of both H. pylori strains and L. gasseri CFS showed no significant effect on cell viability as compared to untreated cells. H. pylori EVs promoted the development of acidic vesicular organelles and the expression of autophagy-related genes (LC3B, ATG5, ATG12, ATG16L1, BECN1, and NOD1), and decreased the expression of MTOR in AGS cells at 12 and 24 h time periods. In addition, the production of LC3B was increased following 12 h of treatment in AGS cells. In contrast, L. gasseri CFS effectively inhibited EVs-induced autophagy, as evidenced by reduced acidic vesicular organelle formation and modulation of autophagy markers. Our study indicated that L. gasseri CFS can effectively suppress H. pylori EV-induced autophagy in AGS cells. Further investigations are required to decipher the mechanism of action L. gasseri CFS and its metabolites on autophagy inhibition induced by H. pylori.

SOX4/HDAC2 Axis Enhances Cell Survivability and Reduces Apoptosis by Activating AKT/MAPK Signaling in Colorectal Cancer.

Increased SOX4 (SRY-related HMG-box) activity aids cellular transformation and metastasis. However, its specific functions and downstream targets remain to be completely elusive in colorectal cancer (CRC). To investigate the role of SOX4 in CRC progression and the underlying mechanism. In the current study, online available datasets of CRC patients were explored to check the expression status of SOX4. To investigate the further functions, SOX4 was overexpressed and knocked down in CRC cells. Colony formation assay, flowcytometry analysis, and MTT assay were used to check for proliferation and apoptosis. Acridine orange staining was done to check the role of SOX4 in autophagy induction. Furthermore, western blot, qRT-PCR, and bioinformatic analysis was done to elucidate the downstream molecular mechanism of SOX4. GEPIA database showed enhanced expression of SOX4 mRNA in CRC tumor, and the human protein atlas (HPA) showed strong staining of SOX4 protein in tumor when compared to the normal tissue. Ectopic expression of SOX4 enhanced colony formation ability as well as rescued cells from apoptosis. SOX4 overexpressed cells showed the formation of acidic vesicular organelles (AVOs) which indicated autophagy. Further results revealed the activation of p-AKT/MAPK molecules upon overexpression of SOX4. SOX4 expression was found to be positively correlated with histone deacetylase 2 (HDAC2). Knockdown of SOX4 or HDAC2 inhibition induced apoptosis, revealed by decrease in BCL2 and increase in BAX expression, and inactivated the p-AKT/MAPK signaling. The study uncovers that SOX4/HDAC2 axis improves cell survivability and reduces apoptosis via activation of the p-AKT/MAPK pathway.

Cytotoxic effect of Ziziphus Spina-Christi extract alone and in combination with doxorubicin on breast cancer cells

Ziziphus Spina-Christi (L.) (ZSC) is a traditional Arabian medicinal plant used to treat inflammatory symptoms, swellings and pain since long. Triple negative breast cancer (TNBC) is a form of cancer with a poor prognosis owing to the paucity of therapy alternatives. Two of the most critical pathways of TNBC development are Wnt/β-catenin signaling and autophagy. In the present study, we intended to identify the possible mechanisms of the cytotoxic effects mediated by ZSC extract on MDA-MB-231 breast cancer cells and to improve the efficacy of DOX in combination with ZSC. The MTT test was used to estimate cell viability and IC50 values. Apoptosis was detected using AnnexinV-FITC detection kit. ELISA was used to measure caspase-3 levels. Cell cycle and the level of autophagosome marker LC3-II were analysed using flow cytometry. Acidic vesicular organelle (AVOs) formation was observed by fluorescence microscopy. Real-time PCR was used to monitor changes in gene expression of β-catenin and autophagic adapter NBR1. It was shown that ZSC treatment dose-dependently inhibited MDA-MB-231 cell viability and induced apoptosis with accompanying elevation of caspase-3 level. Besides ZSC caused a significant elevation in LC3II level and downregulation of NBR1 gene expression with subsequent downregulation of β-catenin gene expression, indicating the inhibition of the oncogenic Wnt pathway. ZSC and DOX combination had synergistic cytotoxic effect by more effective suppression of Wnt pathway and induction of apoptosis and autosis. Keywords: apoptosis, autophagic adapter NBR1, autophagosome marker LC3-II, breast cancer cells, DOX, Wnt/β-catenin signaling, Ziziphus Spina-Christi

Autophagy Induction Constitutes a Targetable Vulnerability in FLT3-Mutant Acute Myeloid Leukemia Cells Treated with FLT3-Inhibitors

Recently, we and others identified autophagy induction as a protective mechanism in FLT3-ITD mutant acute myeloid leukemia (AML) cells upon treatment with FLT3-inhibitors (FLT3i), constituting an increasing issue in clinical practice. Here, we investigated the molecular consequences of autophagy induction upon FLT3i treatment, exploring resistance mechanisms and interrogated whether autophagy inhibition can improve FLT3i antileukemic therapy. Drug response of primary FLT3-ITD AML samples ex vivo treated with FLT3i, quizartinib (AC220, n= 59) and midostaurin (PKC412, n=64), was associated with their transcriptional profile to unravel which molecular programs were enriched in poor responders. Both gene set enrichment analysis (GSEA) and single sample GSEA (ssGSEA) revealed enriched molecular signatures compatible with autophagy activation in poor responders to FLT3i, while sensitive samples enriched molecular signatures consonant with mitochondrial function. Enrichment scores for programs associated with “regulation of autophagy” and “autophagosome organization” were positively correlated to ex vivo response area under the curve values for AC220 and PKC412. To functionally address the molecular pathways associated with autophagy activation upon FLT3i treatment, MOLM-13 and MV4-11 AML cells ( FLT3-ITD) and primary AML samples, were treated with AC220 and PKC412 alone or in combination with the autophagy inhibitor chloroquine (CQ, 5-10μM). In FLT3-ITD AML models, treatment with FLT3i significantly induced the formation of acidic vesicular organelles, suggesting autophagy induction. We also observed a reduction of autophagy regulators in a dose- and time-dependent manner, evidenced by the conversion of LC3B-I to LC3B-II, with degradation of LC3B-II and p62. Furthermore, FLT3i treatment resulted in phosphorylation inhibition of AKT Ser473, mTOR Ser2448 and its downstream protein p70S6K Thr421/Ser424, and phosphorylation reduction of ULK1 Ser757. Combination of FLT3i with CQ (10 μM) significantly reduced cell viability and survival for both PKC412 and AC220 inhibitors. To rule out the off target effects associated with CQ treatment, we performed a knockdown (KD) on the key autophagy mediator ATG5 using shRNA-mediated inhibition in FLT3-ITD cells. In MOLM13 cells, FLT3i treatment in ATG5-KD cells significantly reduced the IC50 (control: 31nM vs. ATG5-KD: 17nM) and increased apoptosis induction (control: 41% vs. ATG5-KD: 58%). We validated these observations in ex vivo treated primary AML samples, where we observed that in FLT3-ITD but not in FLT3 wild-type samples, the combination of FLT3i (PKC412 and AC220) plus autophagy inhibitors (CQ) reduced cell proliferation and survival. In summary, we demonstrated that autophagy induction is a biological process intrinsically associated with drug resistance in FLT3-ITD mutant AMLs when treated with FLT3i. Hence, autophagy inhibition can be leveraged to increase the antileukemic effect of FLT3i and highlights the autophagy as a major acquired biological process associated with FLT3i therapy.

In vitro and in vivo anti-tumor activity of Coenzyme Q0 against TWIST1-overexpressing HNSCC cells: ROS-mediated inhibition of EMT/metastasis and autophagy/apoptosis induction

HNSCC (Head and Heck Squamous Cell Carcinoma) is a reasonably prevalent cancer with a high mortality rate. In this study, we tried to examine the anti-metastasis and apoptosis/autophagy actions of Coenzyme Q0 (CoQ0, 2,3-dimethoxy-5-methyl-1,4-benzoquinone), a derivative of Antrodia camphorata in HNCC TWIST1 overexpressing (FaDu-TWIST1) cells as well as in vivo tumor xenograft mice model. Using fluorescence based cellular assays, western blot and nude mice tumor xenografts, we determined that CoQ0 effectively reduced cell viability and displayed rapid morphological changes in FaDu-TWIST1 cells compared to FaDu cells. Non/sub-cytotoxic concentrations of CoQ0 treatment reduces the cell migration by downregulating TWIST1 and upregulating E-cadherin. Apoptosis produced by CoQ0 was mostly related with caspase-3 activation, PARP cleavage, and VDAC-1 expression. The FaDu-TWIST1 cells treated with CoQ0 exhibits autophagy-mediated LC3-II accumulation and acidic vesicular organelles (AVOs) formation. Pre-treatment with 3-MA and CoQ effectively prevented CoQ0-induced cell death and CoQ0-triggered autophagy in FaDu-TWIST cells as a death mechanism. CoQ0 induces ROS production in FaDu-TWIST1 cells and NAC pre-treatment significantly reduces anti-metastasis, apoptosis, and autophagy. Likewise, ROS-mediated AKT inhibition regulates CoQ0-induced apoptosis/autophagy in FaDu-TWIST1 cells. In vivo studies exhibit, CoQ0 effectively delays and reduces the tumor incidence and burden in FaDu-TWIST1-xenografted nude mice. Current findings display, CoQ0 exhibits a novel anti-cancer mechanism hence, it might be appropriate for anticancer therapy, and a new potent drug for HNSCC.

In vitro and in vivo anti-tumor activity of Antrodia salmonea against twist-overexpressing HNSCC cells: Induction of ROS-mediated autophagic and apoptotic cell death.

Head and neck squamous cell carcinoma (HNSCC) is a relatively common malignancy, characterized by lethal morbidity. Herein, we attempted to investigate the autophagy/apoptosis activities of the submerged fermented broths of Antrodia salmonea (AS) in HNSCC Twist-overexpressing (OECM-1 and FaDu-Twist) cells. AS (0-150μg/mL) effectively reduced cell viability, colony formation, and downregulated Twist expression in OECM-1 and FaDu-Twist cells compared to FaDu cells. AS- induced apoptosis was mainly associated with activation of caspase-3, PARP cleavage, increased expression of VDAC-1 and disproportionation of Bax/Bcl-2. Annexin V/PI staining suggested late apoptosis induction by AS treatment. AS exhibits enhanced autophagy process mediated via LC3-I/II accumulation, increased acidic vesicular organelles (AVOs) formation and p62/SQSTM1 expression feeding into the apoptotic program. However, pre-treatment with autophagy blockers 3-MA and CQ significantly diminished AS-induced cell death. Additionally, suppression of AS-induced ROS release by treatment with antioxidant N-acetylcysteine (NAC) resulted in reduction of apoptotic and autophagic cell death. In vivo studies strengthened the above observations and showed that AS effectively reduced the tumor volume and tumor weight in OECM-1-xenografted nude mice. This study discovered that Antrodia salmonea exhibits a novel anti-cancer mechanism which could be harnessed as a new potent drug for HNSCC treatment.

Potential Therapeutic Effects of Thiazolidinedione on Malignant Glioma.

Glioblastoma multiforme (GBM) is the most common and aggressive primary malignant tumor of the central nervous system. GBM has a very low 5-year survival rate and reaching merely a median of ~15 months even with aggressive treatments. PPARγ (Peroxisome proliferator- activated receptor gamma) agonists (ciglitazone), while being widely used on patients of type 2 diabetes mellitus, also have approved anticancer effects. Their action mechanisms on malignant glioma are not fully understood. The aim of this study is to investigate the potential therapeutic effect of PPARγ agonists on maligant glioma. Glioma cell line and in-vivo/ex-vivo animal model intervened by ciglitazone were used to assess the associated mechanism and therapeutic effect. Our results from in vivo and ex vivo experiments showed that ciglitazone not only inhibited tumor growth and its associated angiogenesis, but it also reduced colony formation and migration of tumors. Ciglitazone inhibited the phosphorylation of STAT3 (signal transducer and activator of transcription 3) (at the point of tyrosine 705 by increasing both the amount and activity of SHP-2 (Src homology region 2-containing protein tyrosine phosphatase 2) proteins, based on evidence obtained from immunoprecipitation and immunohistochemistry. Furthermore, ciglitazone activated proteasomes and lysosomes to degrade cell-cycle-related proteins like Cyclin D1, Cyclin E, CDK2 (Cyclin-dependent kinase 2), and CDK4 (Cyclin-dependent kinase 4). Ciglitazone triggered expressions of LC3 (Microtubule-associated protein 1A/1B-light chain 3) and formation of acidic vesicular organelles (AVOs), both of which were implicated in the autophagy pathway. In conclusion, ciglitazone showed the multiple actions to regulate the growth of glioma, which appeared to be a potential candidate for treating malignant glioma.

Posaconazole inhibits the stemness of cancer stem-like cells by inducing autophagy and suppressing the Wnt/β-catenin/survivin signaling pathway in glioblastoma.

Posaconazole (POS) has been reported to present potential antitumor activity for glioblastoma (GBM). However, its molecular mechanisms remain unclear. In this study, we found that POS has potent cytotoxicity and inhibits cell viability and proliferation in GBM. In addition, we adopted a sphere formation assay to detect the self-renewal capacity, performed western blotting to measure cancer stem-like cells (CSCs) marker proteins (CD133, SOX2, Nanog and Oct4) and applied flow cytometry to monitor the subpopulation of CD144+/CD33+ cells, and the results all demonstrated that POS can remarkably weaken CSCs stemness. Furthermore, western blotting, immunoflurescence, transmission electron microscopy and acridine orange staining were performed to detect autophagy-related proteins (LC3, SQSTM1, Beclin 1 and Atg5), count the numbers of endogenous LC3 puncta, visually observe the ultrastructural morphology of autophagosomes and judge the formation of acidic vesicular organelles, respectively, and the results validated that POS promotes autophagy induction. Importantly, the suppressive effect of POS on CSCs stemness was partially relieved when autophagy was blocked by the autophagy inhibitor chloroquine (CQ) or Atg5 shRNA. Bioinformatic techniques, including weighted gene coexpression network analysis (WGCNA), gene set difference analysis (GSVA) and KEGG pathway analysis, combined with experimental validations showed that survivin, which is implicated in both autophagy and the stem cell index, is one of the target proteins of POS and that POS weakens CSCs stemness via suppressing the Wnt/β-catenin signaling pathway in GBM. Besides, POS-induced autophagy and the Wnt/β-catenin signaling pathway are negative regulators for each other. Finally, the antitumor activity of POS was confirmed in GBM xenograft models in vivo. Consistent with the in vitro conclusions, POS upregulated the expression of LC3 and decreased the expression of CD133, survivin and β-catenin, as shown by the immunohistochemistry analysis. In summary, this work provides an experimental foundation for exploiting POS as a CSCs-targeting antitumor drug for GBM treatment.

Surface layer protein A from hypervirulent Clostridioides difficile ribotype 001 can induce autophagy process in human intestinal epithelial cells

Clostridioides difficile is the leading cause of nosocomial diarrhea with high morbidity and mortality worldwide. C. difficile strains produce a crystalline surface layer protein A (SlpA), which is an absolute necessity for its pathogenesis. However, its pathogenic mechanisms and its pro-inflammatory behavior are not yet fully elucidated. Herein, we report for the first time that SlpA extracted from C. difficile can induce autophagy process in Caco-2 cells. SlpA protein was purified from two C. difficile strains (RT001 and ATCC 700075). The cell viability of Caco-2 cells after exposure with different concentrations (15, 20, 25 μg/mL) of SlpA at various time points (3, 6, 12, 24 h) was measured by MTT assay. Acridine orange staining was used to visualize the hypothetical acidic vesicular organelles. The gene expression of autophagy mediators including LC3B, Atg5, Atg16L, and Beclin-1 was determined by quantitative real-time PCR assay. Western blotting assay was used to detect the expression of LC3B protein. MTT assay showed that different concentrations of SlpA did not induce significant changes in the viability of Caco-2 cells. SlpA at concentration of 20 μg/mL enhanced the formation of acidic vesicular organelles in Caco-2 cells after 12 h of exposure. Moreover, SlpA treatment significantly increased the expression of autophagy-associated genes, and increased the expression of LC3B protein in Caco-2 cells. In conclusion, our study demonstrated that SlpA is capable to induce autophagy in intestinal epithelial cells. These findings reveal a novel mechanism for the pathogenesis of C. difficile mediated by its SLPs.

Proliferation and Invasion of Melanoma Are Suppressed by a Plant Protease Inhibitor, Leading to Downregulation of Survival/Death-Related Proteins.

Cell adhesion and migration are crucial for cancer progression and malignancy. Drugs available for the treatment of metastatic melanoma are expensive and unfit for certain patients. Therefore, there is still a need to identify new drugs that block tumor cell development. We investigated the effects of Enterolobium contortisiliquum trypsin inhibitor (EcTI), a protease inhibitor, on cell viability, cell migration, invasion, cell adhesion, and cell death (hallmarks of cancer) in vitro using human melanoma cells (SK-MEL-28 and CHL-1). Although EcTI did not affect non-tumor cells, it significantly inhibited the proliferation, migration, invasion, and adhesion of melanoma cells. Investigation of the underlying mechanisms revealed that EcTI triggered apoptosis and nuclear shrinkage, increased PI uptake, activated effector caspases-3/7, and produced reactive oxygen species (ROS). Furthermore, EcTI disrupted the mitochondrial membrane potential, altered calcium homeostasis, and modified proteins associated with survival and apoptosis/autophagy regulation. Acridine orange staining indicated acidic vesicular organelle formation upon EcTI treatment, demonstrating a cell death display. Electronic microscopy corroborated the apoptotic pattern by allowing the visualization of apoptotic bodies, mitochondrial cristae disorganization, and autophagic vesicles. Taken together, these results provide new insights into the anti-cancer properties of the natural EcTI protein, establishing it as a promising new therapeutic drug for use in melanoma treatment.

Naringenin Induces ROS-Mediated ER Stress, Autophagy, and Apoptosis in Human Osteosarcoma Cell Lines.

Osteosarcoma, a primary bone tumor, responds poorly to chemotherapy and radiation therapy in children and young adults; hence, as the basis for an alternative treatment, this study investigated the cytotoxic and antiproliferative effects of naringenin on osteosarcoma cell lines, HOS and U2OS, by using cell counting kit-8 and colony formation assays. DNA fragmentation and the increase in the G2/M phase in HOS and U2OS cells upon treatment with various naringenin concentrations were determined by using the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and Annexin V/propidium iodide double staining, respectively. Flow cytometry was performed, and 2′,7′-dichlorodihydrofluorescein diacetate, JC-1, and Fluo-4 AM ester probes were examined for reactive oxygen species (ROS) generation, mitochondrial membrane potential, and intracellular calcium levels, respectively. Caspase activation, cell cycle, cytosolic and mitochondrial, and autophagy-related proteins were determined using western blotting. The results indicated that naringenin significantly inhibited viability and proliferation of osteosarcoma cells in a dose-dependent manner. In addition, naringenin induced cell cycle arrest in osteosarcoma cells by inhibiting cyclin B1 and cyclin-dependent kinase 1 expression and upregulating p21 expression. Furthermore, naringenin significantly inhibited the growth of osteosarcoma cells by increasing the intracellular ROS level. Naringenin induced endoplasmic reticulum (ER) stress-mediated apoptosis through the upregulation of ER stress markers, GRP78 and GRP94. Naringenin caused acidic vesicular organelle formation and increased autophagolysosomes, microtubule-associated protein-light chain 3-II protein levels, and autophagy. The findings suggest that the induction of cell apoptosis, cell cycle arrest, and autophagy by naringenin through mitochondrial dysfunction, ROS production, and ER stress signaling pathways contribute to the antiproliferative effect of naringenin on osteosarcoma cells.

Nanosized copper particles induced mesangial cell toxicity via the autophagy pathway.

Nanosized copper particles (nano Cu) have been incorporated into products in multiple industries, although studies have demonstrated that these particles are nephrotoxic. We investigated the cytotoxicity of nanosized copper particles on rat mesangial cells and measured rates of apoptosis, the expression of caspase-3, and generation of reactive oxygen species. We also measured autophagy through the acridine orange (AO) staining and expression of Beclin-1, microtubule-associated protein 1 light chain 3, and p62 to screen the underlying mechanism of toxicity. Nanosized copper particles inhibited mesangial cell viability, up-regulated the activity of caspase-3, and increased the rates of apoptosis and the generation of reactive oxygen species in a concentration-dependent manner. Exposure to nano Cu increased the formation of acidic vesicular organelles and the expression of Beclin-1, microtubule-associated protein 1 light chain 3, and p62, and treatment with an autophagy inhibitor reduced nephrotoxicity. This indicated that the autophagy pathway is involved in the toxicity induced by nanosized copper particles to mesangial cells. This finding can contribute to the development of safety guidelines for the evaluation of nanomaterials in the future.

Oleanolic acid induces apoptosis and autophagy via the PI3K/AKT/mTOR pathway in AGS human gastric cancer cells

• Oleanolic acid inhibited AGS human gastric cancer cells by inducing apoptosis. • Oleanolic acid induced protective-autophagy in AGS cancer cell. • Oleanolic acid induced apoptosis and autophagy through PI3K/AKT/mTOR pathway. • Oleanolic acid suppress tumor growth by downregulating AKT pathway. Oleanolic acid (OA) is widely distributed in food and medicinal plants, it reportedly exerts anti-inflammatory and anti-cancer effects. In this study, we investigated the effect of OA on human gastric cancer cells AGS in vitro and in vivo. The OA treatment significantly inhibited the AGS cell viability. Apoptosis was confirmed via annexin V/PI staining and 4′,6-diamidino-2-phenylindole (DAPI) staining. The results from western blotting revealed that treatment with OA affected apoptosis-related protein. Meanwhile, OA induced autophagy, characterized by the formation of autophagic vacuoles and acidic vesicular organelles, also increased autophagy-related protein. Inhibition of autophagy further reduced cell proliferation. Moreover, OA treatment decreased phosphorylation of PI3K/AKT/mTOR pathway proteins. Finally, we found that OA reduced tumor volume and weight in xenograft mice via apoptosis without side effects. Overall, our study provides experimental evidence for the anti-cancer action of OA and suggests the possibility of its use as an adjuvant in gastric cancer therapy.

AKF-D52, a Synthetic Phenoxypyrimidine-Urea Derivative, Triggers Extrinsic/Intrinsic Apoptosis and Cytoprotective Autophagy in Human Non-Small Cell Lung Cancer Cells.

Simple SummaryWe previously reported the antiproliferative effects of a phenoxypyridine urea derivative. In this study, we aimed to investigate the antiproliferative effects of 1-(3,5-dimethoxyphenyl)-3-(4-(3-methoxyphenoxy)-2-((4-morpholinophenyl)amino)pyrimidin-5-yl)urea (AKF-D52) in non-small cell lung cancer cells. We found that (i) AKF-D52 induces apoptosis in caspase-dependent and caspase-independent pathways; (ii) AKF-D52-induced apoptosis is caused by the clustering of a death-inducing signaling complex and mitochondrial-dependent signaling; (iii) AKF-D52 induces cytoprotective autophagy, and pre-treatment with an autophagy inhibitor enhances the apoptotic effect of AKF-D52; and (iv) AKF-D52-induced apoptosis and autophagy are attenuated by the reactive oxygen species (ROS) scavenger α-tocopherol. Furthermore, AKF-D52 suppressed tumor growth in a xenograft mouse model. Collectively, our findings regarding the efficacy and molecular mechanisms of AKF-D52 identify this compound as a potential therapeutic agent for the treatment of lung cancer.Previously, we discovered that 1-(3,5-dimethoxyphenyl)-3-(4-(3-methoxyphenoxy)-2-((4-morpholinophenyl)amino)pyrimidin-5-yl)urea (AKF-D52), a synthetic phenoxypyrimidine urea derivative, acts as a growth inhibitor of various cancer cell types. In this study, we elucidated the antiproliferative properties of AFK-D52 and underlying mechanisms in non-small cell lung cancer (NSCLC) cells and an A549 xenograft animal model. AKF-D52 was found to induce both caspase-dependent and -independent apoptotic cell death. Furthermore, the mitochondrial component of the AKF-D52-induced apoptosis mechanism involves a reduction in mitochondrial membrane potential and regulation in B cell lymphoma-2 family protein expression. Moreover, AKF-D52 activates the extrinsic pathway through up-regulated expression of death receptor 3 and Fas and then the formation of a death-inducing signaling complex. AKF-D52 also induced autophagy by increasing acidic vesicular organelle formation and microtubule-associated protein 1A/1B-light chain 3-II levels and reducing p62 levels. Notably, pretreatment with autophagy inhibitors enhanced AKF-D52-induced cell death, indicating that the induced autophagy is cytoprotective. AKF-D52 treatment also triggered reactive oxygen species (ROS) production in NSCLC cells, whereas the antioxidant α-tocopherol abolished AKF-D52-induced cell death. In a xenograft lung cancer mouse model, AKF-D52 administration attenuated tumor growth by inducing apoptosis and autophagy in tumor tissues. Collectively, our data indicate that AKF-D52-induced ROS production plays a role in mediating apoptosis and cytoprotective autophagy in NSCLC.

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.

Antrodia salmonea induces apoptosis and enhances cytoprotective autophagy in colon cancer cells.

A traditional Chinese medicinal fungus, Antrodia salmonea (AS), with antioxidant properties is familiar in Taiwan but anti-cancer activity of AS in human colon cancer is ambiguous. Hence, we explored the anti-cancer activity of AS in colon cancer cells. 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that AS showed a remarkable effect on cell viability in colon cancer cells; SW620, HCT116, and HT29. Annexin V/propidium iodide (PI) stained cells indicated that AS induced both early/late apoptosis in SW620 cells. Additionally, cells treated with AS induced caspase-3 activation, poly (ADP-ribose) polymerase (PARP) cleavage, mitochondrial dysfunction, and Bcl-2 associated X (Bax)/B-cell lymphoma (Bcl-2) dysregulation. Microtubule- associated protein 1A/1B-light chain 3B (LC3-II) accumulation, sequestosome 1 (p62/SQSTM1) activation, autophagy related 4B cysteine peptidase (ATG4B) inactivation, acidic vesicular organelles (AVOs) formation, and Beclin-1/Bcl-2 dysregulation revealed that AS-induced autophagy. Interestingly, cells pretreated with 3-methyladenine (3-MA) strengthened AS-induced caspase-3/apoptosis. Suppression of apoptosis by z-Val-Ala-Asp fluoromethyl ketone (Z-VAD-FMK) did not however block AS-induced autophagy, suggesting that autophagy was not attenuated by the AS-induced apoptosis. Application of N-acetylcysteine (NAC) prevented AS-induced cell death, caspase-3 activation, LC3-II accumulation, and AVOs formation, indicating that AS-induced apoptosis and autophagy was mediated by reactive oxygen species (ROS). Furthermore, AS-induced cytoprotective autophagy and apoptosis through extracellular signal-regulated kinase (ERK) signaling cascades. Moreover, in vivo data disclosed that AS inhibited colitis-associated tumorigenesis in azoxymethane (AOM)-dextran sodium sulphate (DSS)-treated mice. For the first time, we report the anti-cancer properties of this potentially advantageous mushroom for the treatment of human colon cancer.

Glucocappasalin Induces G2/M-Phase Arrest, Apoptosis, and Autophagy Pathways by Targeting CDK1 and PLK1 in Cervical Carcinoma Cells.

Glucocappasalin (GCP), a natural product derived from the seeds of Descurainia sophia (L.) Webb. ex Prantl, exhibits potential antitumor activity in HeLa cervical carcinoma cells. In this study, we investigated the anti-cervical cancer property of GCP through the induction of cell cycle arrest, apoptosis, and autophagy in vitro and in vivo, and elucidated the underlying molecular mechanisms. We demonstrated that treatment with GCP inhibited the growth of HeLa, Siha, and Ca Ski cell lines in a dose-dependent manner, with HeLa cells displaying particular sensitivity to the GCP treatment. Subsequently, the expression of cyclin-dependent kinase 1 (CDK1) and polo like kinase 1 (PLK1) were evaluated in HeLa cells using the CDK1 kinase assay kit, the fluorescence polarization assay, real-time quantitative PCR, and western blotting. Our results demonstrate that GCP could be employed to attenuate the expression of CDK1 and PLK1 in a dose- and time-dependent manner. The complementary results obtained by flow cytometry and western blotting allowed us to postulate that GCP may exhibit its antitumor effects by inducing G2/M cell cycle arrest. Moreover, HeLa cells treated with GCP exhibited a loss in mitochondrial membrane potential, together with the activation of caspases 3 and 9, and poly ADP-ribose polymerase (PARP). Additionally, we found that GCP could increase the formation of acidic vesicular organelles (AVOs), as well as the levels of Beclin1, LC3-II, p62, and Atg5 proteins in HeLa cells. Further studies indicated that GCP triggered autophagy via the suppression of the PI3K/AKT/mTOR signaling pathways. The autophagy inhibitor 3-methyladenine (3-MA) was used to determine whether autophagy affects the apoptosis induced by GCP. Interestingly, the inhibition of autophagy attenuated apoptosis. In vivo anti-tumor experiments indicated that GCP (60 mg/kg, i.p.) markedly reduced the growth of HeLa xenografts in nude mice without apparent toxicity. Taken together, we demonstrate that GCP induces cell cycle G2/M-phase arrest, apoptosis, and autophagy by acting on the PI3K/AKT/mTOR signaling pathways in cervical carcinoma cells. Thus, GCP may represent a promising agent in the eradication of cervical cancer.