Crosstalk between apoptosis and autophagy: molecular mechanisms and therapeutic strategies in cancer

The e-liquid flavoring cinnamaldehyde induces cellular stress responses in human proximal tubule (HK-2) kidney cells

Flavored e-liquid use has become popular among e-cigarette users recently, but the effects of such products outside the lung are not well characterized. In this work, acute exposure to the popular flavoring cinnamaldehyde (CIN) was performed on human proximal tubule (HK-2) kidney cells. Cells were exposed to 0-100 µM CIN for 24-48 h and cellular stress responses were assessed. Mitochondrial viability via MTT assay was significantly decreased at 20 µM for 24 and 48 h exposure. Seahorse XFp analysis showed significantly decreased mitochondrial energy output at 20 µM by 24 h exposure, in addition to significantly reduced ATP Synthase expression. Seahorse analysis also revealed significantly decreased glycolytic function at 20 µM by 24 h exposure, suggesting inability of glycolytic processes to compensate for reduced mitochondrial energy output. Cleaved caspase-3 expression, a mediator of apoptosis, was significantly increased at the 24 h mark. C/EBP homologous protein (CHOP) expression, a mediator of ER-induced apoptosis, was induced by 48 h and subsequently lost at the highest concentration of 100 µM. This decrease was accompanied by a simultaneous decrease in its downstream target cleaved caspase-3 at the 48 h mark. The autophagy marker microtubule-associated protein 1 A/1B light chain 3 (LC3B-I and LC3B-II) expression was significantly increased at 100 µM by 24 h. Autophagy-related 7 (ATG7) protein and mitophagy-related proteins PTEN-induced putative kinase 1 (PINK1) and PARKIN expression were significantly reduced at 24 and 48 h exposure. These results indicate acute exposure to CIN in the kidney HK-2 model induces mitochondrial dysfunction and cellular stress responses.

The E-liquid flavoring vanillin alters energy and autophagic pathways in human proximal tubule (HK-2) epithelial cells

The use of flavored e-liquids in electronic nicotine delivery systems (ENDS) has become very popular in recent years, but effects of these products have not been well characterized outside the lung. In this study, acute exposure to the popular flavoring vanillin (VAN) was performed on human proximal tubule (HK-2) kidney cells. Cells were exposed to 0-1000 μM VAN for 24 or 48 h and cellular stress responses were determined. Mitochondrial viability using MTT assay showed a significant decrease between the control and 1000 μM group by 48 h. Seahorse XFp analysis showed significantly increased basal respiration, ATP production, and proton leak after 24 h exposure. By 48 h exposure, these parameters remained significantly increased in addition to non-mitochondrial respiration and maximal respiration. Glycolytic activity after 24 h exposure showed significant decreases in glycolysis, glycolytic capacity, glycolytic reserve, and non-glycolytic acidification. The autophagy markers microtubule-associated protein 1A/1B light chain 3 (LC3B-I and LC3B-II) were probed via western blotting. The ratio of LC3B-II/LC3B-I was significantly increased after 24 h exposure to VAN, but by 48 h this ratio significantly decreased. The mitophagy marker PINK1 showed an increasing trend at 24 h, and its downstream target Parkin was significantly increased between the control and 750 μM group only. Finally, the oxidative stress marker 4-HNE was significantly decreased after 48 h exposure to VAN. These results indicate that acute exposure to VAN in the kidney HK-2 model can induce energy and autophagic changes within the cell.

The Role of Bcl-2 and Beclin-1 Complex in "Switching" between Apoptosis and Autophagy in Human Glioma Cells upon LY294002 and Sorafenib Treatment

BACKGROUND

Gliomas are the most malignant tumors of the central nervous system. One of the factors in their high drug resistance is avoiding programmed death (PCD) induction. This is related to the overexpression of intracellular survival pathways: PI3K-Akt/PKB-mTOR and Ras-Raf-MEK-ERK. Apoptosis and autophagy are co-existing processes due to the interactions between Bcl-2 and beclin-1 proteins. Their complex may be a molecular "toggle-switch" between PCD types. The aim of this research was to investigate the role of Bcl-2:beclin-1 complex in glioma cell elimination through the combined action of LY294002 and sorafenib.

METHODS

Drug cytotoxicity was estimated with an MTT test. The type of cell death was evaluated using variant microscopy techniques (fluorochrome staining, immunocytochemistry, and transmission electron microscopy), as well as the Bcl-2:beclin-1 complex formation and protein localization. Molecular analysis of PCD indicators was conducted through immunoblotting, immunoprecipitation, and ELISA testing. SiRNA was used to block Bcl-2 and beclin-1 expression.

RESULTS

The results showed the inhibitors used in simultaneous application resulted in Bcl-2:beclin-1 complex formation and apoptosis becoming dominant. This was accompanied by changes in the location of the tested proteins.

CONCLUSIONS

"Switching" between apoptosis and autophagy using PI3K and Raf inhibitors with Bcl-2:beclin-1 complex formation opens new therapeutic perspectives against gliomas.

Luteolin as a potential hepatoprotective drug: Molecular mechanisms and treatment strategies

Luteolin is a flavonoid widely present in various traditional Chinese medicines. In recent years, luteolin has received more attention due to its impressive liver protective effect, such as metabolic associated fatty liver disease, hepatic fibrosis and hepatoma. This article summarizes the pharmacological effects, pharmacokinetic characteristics, and toxicity of luteolin against liver diseases, and provides prospect. The results indicate that luteolin improves liver lesions through various mechanisms, including inhibiting inflammatory factors, reducing oxidative stress, regulating lipid balance, slowing down excessive aggregation of extracellular matrix, inducing apoptosis and autophagy of liver cancer cells. Pharmacokinetics research manifested that due to metabolic effects, the bioavailability of luteolin is relatively low. It is worth noting that appropriate modification, new delivery systems, and derivatives can enhance its bioavailability. Although many studies have shown that the toxicity of luteolin is minimal, strict toxicity experiments are still needed to evaluate its safety and promote its reasonable development. In addition, this study also discussed the clinical applications related to luteolin, indicating that it is a key component of commonly used liver protective drugs in clinical practice. In view of its excellent pharmacological effects, luteolin is expected to become a potential drug for the treatment of various liver diseases.

YAP1 synergize with YY1 transcriptional co-repress DUSP1 to induce osimertinib resistant by activating the EGFR/MAPK pathway and abrogating autophagy in non-small cell lung cancer

YAP1 is a well-known core effector of the Hippo pathway in tumors, but its potential role in osimertinib resistance remained unexplored. Our study provides evidence that YAP1 acts as a potent promoter of osimertinib resistance. By inhibiting YAP1 with a novel inhibitor, CA3, and combining it with osimertinib, we observed a significant suppression of cell proliferation and metastasis, induction of apoptosis and autophagy, and a delay in the emergence of osimertinib resistance. Interestingly, CA3 combined with osimertinib executed its anti-metastasis and pro-tumor apoptosis in part through autophagy. Mechanistically, we found that YAP1, in collaboration with YY1, transcriptionally represses DUSP1, leading to the dephosphorylation of the EGFR/MEK/ERK pathway and YAP1 phosphorylation in osimertinib-resistant cells. Our results also validate that CA3, in combination with osimertinib, executes its anti-metastasis and pro-tumor apoptosis partly through autophagy and the YAP1/DUSP1/EGFR/MEK/ERK regulatory feedback loop in osimertinib-resistant cells. Remarkably, our findings illustrate that YAP1 protein is upregulated in patients after osimertinib treatment and osimertinib resistance. Overall, our study confirms that the YAP1 inhibitor CA3 increases DUSP1 with concomitant activation of the EGFR/MAPK pathway and induces autophagy to enhance the efficacy of third-generation EGFR-TKI treatments for NSCLC patients.

The in vitro and in vivo anticancer activities of Antrodia salmonea through inhibition of metastasis and induction of ROS-mediated apoptotic and autophagic cell death in human glioblastoma cells

BACKGROUND

Antrodia salmonea (AS) exhibits anticancer activities against various cancers.

OBJECTIVE

This study investigated the anticancer activities of AS on human glioblastoma (GBM8401 and U87MG) cells both in vitro and in vivo and explained the underlying molecular mechanism.

METHODS

MTT, colony formation, migration/invasion assay, immunoblotting, immunofluorescence, TUNEL, Annexin V/PI staining, AO staining, GFP-LC3 transfection, TEM, qPCR, siLC3, DCFH2-DA assay, and xenografted-nude mice were used to assess the potential of AS therapy.

RESULTS

AS treatment retarded growth and suppressed colony formation in glioblastoma cells. AS attenuates EMT by suppressing invasion and migration, increasing E-cadherin expression, decreasing Twist, Snail, and N-cadherin expression, and inhibiting Wnt/β-catenin pathways in GBM8401 and U87MG cells. Furthermore, AS induced apoptosis by activating caspase-3, cleaving PARP, and dysregulating Bax and Bcl-2 in both cell lines. TUNEL assay and Annexin V/PI staining indicated AS-mediated late apoptosis. Interestingly, AS induced autophagic cell death by LC3-II accumulation, AVO formation, autophagosome GFP-LC3 puncta, p62/SQSTM1 expression, and ATG4B inhibition in GBM8401 and U87MG cells. TEM data revealed that AS favored autophagosome and autolysosome formation. The autophagy inhibitors 3-MA/CQ and LC3 knockdown suppressed AS-induced apoptosis in glioblastoma cells, indicating that the inhibition of autophagy decreased AS-induced apoptosis. Notably, the antioxidant N-acetylcysteine (NAC) inhibited AS-mediated ROS production and AS-induced apoptotic and autophagic cell death. Furthermore, AS induced ROS-mediated inhibition of the PI3K/AKT/mTOR signaling pathway. AS reduced the tumor burden in GBM8401-xenografted nude mice and significantly modulated tumor xenografts by inducing anti-EMT, apoptosis, and autophagy. AS could be a potential antitumor agent in human glioblastoma treatment.

BMX, a specific HDAC8 inhibitor, with TMZ for advanced CRC therapy: a novel synergic effect to elicit p53-, β-catenin- and MGMT-dependent apoptotic cell death

BACKGROUND

Despite advances in treatment, patients with refractory colorectal cancer (CRC) still have poor long-term survival, so there is a need for more effective therapeutic options.

METHODS

To evaluate the HDAC8 inhibition efficacy as a CRC treatment, we examined the effects of various HDAC8 inhibitors (HDAC8i), including BMX (NBM-T-L-BMX-OS01) in combination with temozolomide (TMZ) or other standard CRC drugs on p53 mutated HT29 cells, as well as wild-type p53 HCT116 and RKO cells.

RESULTS

We showed that HDAC8i with TMZ cotreatment resulted in HT29 arrest in the S and G2/M phase, whereas HCT116 and RKO arrest in the G0/G1 phase was accompanied by high sub-G1. Subsequently, this combination approach upregulated p53-mediated MGMT inhibition, leading to apoptosis. Furthermore, we observed the cotreatment also enabled triggering of cell senescence and decreased expression of stem cell biomarkers. Mechanistically, we found down-expression levels of β-catenin, cyclin D1 and c-Myc via GSK3β/β-catenin signaling. Intriguingly, autophagy also contributes to cell death under the opposite status of β-catenin/p62 axis, suggesting that there exists a negative feedback regulation between Wnt/β-catenin and autophagy. Consistently, the Gene Set Enrichment Analysis (GSEA) indicated both apoptotic and autophagy biomarkers in HT29 and RKO were upregulated after treating with BMX.

CONCLUSIONS

BMX may act as a HDAC8 eraser and in combination with reframed-TMZ generates a remarkable synergic effect, providing a novel therapeutic target for various CRCs. Video Abstract.

6‑Gingerol suppresses cell viability, migration and invasion via inhibiting EMT, and inducing autophagy and ferroptosis in LPS‑stimulated and LPS‑unstimulated prostate cancer cells

6-Gingerol is a bioactive compound isolated from Zingiber officinale. 6-Gingerol has been shown to have anticancer effects in numerous types of cancer cell. The mechanisms underlying the anticancer effect of 6-Gingerol in prostate cancer requires investigation. In the present study, the effect on cell viability of 6-Gingerol on LNCaP, PC3 and DU145 prostate cancer cells were determined using the MTT and colony formation assays. 6-Gingerol significantly inhibited cell migration, adhesion and invasion in LPS-stimulated and LPS-unstimulated prostate cancer cells. Furthermore, these changes were accompanied by alterations in the protein expression levels of epithelial-mesenchymal transition biomarkers, including E-cadherin, N-cadherin, Vimentin and zonula occludens-1. 6-Gingerol also induced autophagy by significantly increasing LC3B-II and Beclin-1 protein expression levels in prostate cancer cells. Combining 6-Gingerol with LY294002, an autophagy inhibitor, significantly increased cell survival in DU145 cells. Furthermore, 6-Gingerol significantly decreased the protein expression levels of glutathione (GSH) peroxidase 4 and nuclear factor erythroid 2-related factor 2 in prostate cancer cells. Reactive oxygen species (ROS) levels were significantly increased but GSH levels were decreased following 6-Gingerol treatment in prostate cancer cells. Co-treatment with the ferroptosis inhibitor, ferrostatin-1, significantly increased cell viability and significantly decreased ROS levels in 6-Gingerol-treated cells. These results suggested that 6-Gingerol may have inhibited prostate cell cancer viability via the regulation of autophagy and ferroptosis. In addition, 6-Gingerol inhibited cell migration, adhesion and invasion via the regulation of EMT-related protein expression levels in LPS-stimulated and LPS-unstimulated prostate cancer cells. In conclusion, 6-Gingerol may induce protective autophagy, autophagic cell death and ferroptosis-mediated cell death in prostate cancer cells. These findings may provide a strategy for the treatment and prevention of prostate cancer.

Targeting Cell Death Mechanism Specifically in Triple Negative Breast Cancer Cell Lines

Triple negative breast cancer (TNBC) is currently associated with a lack of treatment options. Arsenic derivatives have shown antitumoral activity both in vitro and in vivo; however, their mode of action is not completely understood. In this work we evaluate the response to arsenate of the double positive MCF-7 breast cancer cell line as well as of two different TNBC cell lines, Hs578T and MDA-MB-231. Multimodal experiments were conducted to this end, using functional assays and microarrays. Arsenate was found to induce cytoskeletal alteration, autophagy and apoptosis in TNBC cells, and moderate effects in MCF-7 cells. Gene expression analysis showed that the TNBC cell lines’ response to arsenate was more prominent in the G2M checkpoint, autophagy and apoptosis compared to the Human Mammary Epithelial Cells (HMEC) and MCF-7 cell lines. We confirmed the downregulation of anti-apoptotic genes (MCL1, BCL2, TGFβ1 and CCND1) by qRT-PCR, and on the protein level, for TGFβ2, by ELISA. Insight into the mode of action of arsenate in TNBC cell lines it is provided, and we concluded that TNBC and non-TNBC cell lines reacted differently to arsenate treatment in this particular experimental setup. We suggest the future research of arsenate as a treatment strategy against TNBC.

Autolysosomes and caspase-3 control the biogenesis and release of immunogenic apoptotic exosomes

Apoptotic exosome-like vesicles (ApoExos) are a novel type of extracellular vesicle that contribute to the propagation of inflammation at sites of vascular injury when released by dying cells. ApoExos are characterized by the presence of the C-terminal perlecan LG3 fragment and 20S proteasome, and they are produced downstream of caspase-3 activation. In the present study, we assessed the relative roles of autophagy and caspase-3-mediated pathways in controlling the biogenesis and secretion of immunogenic ApoExos. Using electron microscopy and confocal immunofluorescence microscopy in serum-starved endothelial cells, we identified large autolysosomes resulting from the fusion of lysosomes, multivesicular bodies, and autophagosomes as a site of ApoExo biogenesis. Inhibition of autophagy with ATG7 siRNA or biochemical inhibitors (wortmannin and bafilomycin) coupled with proteomics analysis showed that autophagy regulated the processing of perlecan into LG3 and its loading onto ApoExos but was dispensable for ApoExo biogenesis. Caspase-3 activation was identified using caspase-3-deficient endothelial cells or caspase inhibitors as a pivotal regulator of fusion events between autolysosomes and the cell membrane, therefore regulating the release of immunogenic ApoExos. Collectively, these findings identified autolysosomes as a site of ApoExo biogenesis and caspase-3 as a crucial regulator of autolysosome cell membrane interactions involved in the secretion of immunogenic ApoExos.

Deglycosylated EpCAM regulates proliferation by enhancing autophagy of breast cancer cells via PI3K/Akt/mTOR pathway

Autophagy is an important regulator of cellular homeostasis and its dysregulation often results in cancer. Aberrant glycosylation induced by oncogenic transformation contributes to tumor invasion and metastasis. In a previous study, we have demonstrated that EpCAM, a glycosylation protein, is associated with cell growth and metastasis in breast cancer. But the effect of EpCAM glycosylation on autophagy is not clear. the precise mechanism of regulation remains largely unknown. In this study, breast cancer cells were transfected with N-glycosylation mutation EpCAM plasmid to express deglycosylated EpCAM. The result showed that deglycosylated EpCAM promoted autophagy in breast cancer cells. We further confirmed this conclusion with the activator (Rapamycin, RAP) and inhibitor (Wortmannin) of autophagy. We also found that deglycosylated EpCAM promoted apoptosis and inhibited proliferation through activating autophagy by suppressing Akt/mTOR signaling pathway in breast cancer cells. These findings represent a novel mechanism by which deglycosylated EpCAM inhibits proliferation by enhancing autophagy of breast cancer cells via PI3K/Akt/mTOR pathway. In conclusion, the combination of autophagy modulation and EpCAM targeted therapy is a promising therapeutic strategy in the treatment of breast cancer.

Regulation of β1-integrin in autophagy and apoptosis of gastric epithelial cells infected with Helicobacter pylori

Helicobacter pylori infection is an essential factor in the development of human gastric diseases, but its pathogenic mechanism is still unclear. In this work we have showed that, the LC3II levels were increased and β1-integrin levels were decreased in H. pylori-positive human gastric tissue samples and H. pylori co-cultured GES-1 cells. There was significant upregulation of LC3II levels and downregulation of P62 levels in GES-1 cells after β1-integrin knockdown co-cultured with H. pylori. This indicated that β1-integrin downregulation promoted autophagy in GES-1 cells after H. pylori infection. The cell apoptosis rate and poly ADP-ribose polymerase (PARP) and caspase-3 activities were increased in GES-1 cells pretreated with 3-methyladenine (3-MA ) after H. pylori infection. Furthermore, there was a significant decrease in apoptosis of β1-integrin knockdown GES-1 cells co-cultured with H. pylori; apoptosis was also downregulated in β1-integrin knockdown- and 3-MA-treated GES-1 cells co-cultured with H. pylori. Correspondingly, PARP and caspase-3 activities were decreased in β1-integrin knockdown cells co-cultured with H. pylori and β1-integrin knockdown-3-MA-treated-1 cells with H. pylori infection. Thus, β1-integrin is a novel autophagy and apoptosis regulator during H. pylori infection. However, inhibition of autophagy did not reverse the decrease in apoptosis caused by downregulation of β1-integrin.

Toxic mechanisms and pharmacological properties of euptox A, a toxic monomer from A. adenophora

A. adenophora (Spreng.) R.M. King & H. Rob. is as invasive plant known to cause toxicity in humans and animals. The plant's toxic activities have been associated with some toxic phytochemicals present in the plant. One of the major phytochemicals that have been reported to induce toxicity in various organs is euptox A (9-oxo-10, 11-dehydroageraphorone). Previous studies have reported that the main target organs of euptox A are the liver and spleen. Although, many studies have reported on euptox A toxicity in rats and mice, the mechanism of action and the beneficial uses of this toxin as well as it potential uses have not been fully established in literatures. Therefore, this review firstly, aims at elaborating on the toxic effects and mechanism of action of euptox A to give basic knowledge to researchers to help in the development of strategies that will reduce its toxicity to the environment. Secondly, this paper will also report on some beneficial uses of euptox A in recent years as well as suggest some future potential applications of this toxin to help in the utilization of this plant resource.

Celecoxib reverses the glioblastoma chemo-resistance to temozolomide through mitochondrial metabolism

Temozolomide (TMZ) is used for the treatment of high-grade gliomas. Acquired chemoresistance is a serious limitation to the therapy with more than 90% of recurrent gliomas showing little response to a second line of chemotherapy. Therefore, it is necessary to explore an alternative strategy to enhance the sensitivity of glioblastoma (GBM) to TMZ in neuro-oncology. Celecoxib is well known and widely used in anti-inflammatory and analgesic. Cyclooxygenase-2 (COX-2) expression has been linked to the prognosis, angiogenesis, and radiation sensitivity of many malignancies such as primitive neuroectodermal tumor and advanced melanoma. The objective of this study was to explore the chemotherapy-sensitizing effect of celecoxib on TMZ in GBM cells and its potential mechanisms. From the study, we found that the combination therapy (TMZ 250uM+celecoxib 30uM) showed excellent inhibitory effect to the GBM, the LN229 and LN18, which were the TMZ resistant GBM cell lines. Our data suggest that the combination therapy may inhibits cell proliferation, increases apoptosis, and increases the autophagy on LN229 and LN18. The potential molecular mechanisms were related to mitochondrial metabolism and respiratory chain inhibition.

Autophagy based cellular physiological strategies target oncogenic progression

Evidence accumulated from past findings indicates that defective proteostasis may contribute to risk factors for cancer generation. Irregular assembly of abnormal proteins catalyzes the disturbance of cellular proteostasis and induces the ability of abnormal cellular proliferation. The autophagy mechanism plays a key role in the regular clearance of abnormal/poor lipids, proteins, and various cellular organelles. The results of functional and effective autophagy deliver normal cellular homeostasis, which establishes supportive metabolism and avoids unexpected tumorigenesis events. Still, the precise molecular mechanism of autophagy in tumor suppression has not been clear. How autophagy triggers selective or nonselective bulk degradation to dissipate tumor promotion under stress conditions is not clear. Under proteotoxic insults to knockdown the drive of tumorigenesis, it is critical for us to figure out the detailed molecular functions of autophagy in human cancers. The current article summarizes autophagy-based theragnostic strategies targeting various phases of tumorigenesis and suggests the preventive roles of autophagy against tumor progression. A better understanding of various molecular partners of autophagic flux will improve and innovate therapeutic approaches based on autophagic-susceptible effects against cellular oncogenic transformation.

Roles of the tumor suppressor inhibitor of growth family member 4 (ING4) in cancer

Inhibitor of growth family member 4 (ING4) is best known as a tumor suppressor that is frequently downregulated, deleted, or mutated in many cancers. ING4 regulates a broad array of tumor-related processes including proliferation, apoptosis, migration, autophagy, invasion, angiogenesis, DNA repair and chromatin remodeling. ING4 alters local chromatin structure by functioning as an epigenetic reader of H3K4 trimethylation histone marks (H3K4Me3) and regulating gene transcription through directing histone acetyltransferase (HAT) and histone deacetylase (HDAC) protein complexes. ING4 may serve as a useful prognostic biomarker for many cancer types and help guide treatment decisions. This review provides an overview of ING4's central functions in gene expression and summarizes current literature on the role of ING4 in cancer and its possible use in therapy.

Treating MCF7 breast cancer cell with proteasome inhibitor Bortezomib restores apoptotic factors and sensitizes cell to Docetaxel

Chemoresistance is the leading cause of limiting long-term treatment success in cancer cells. Anticancer drugs usually kill cells through apoptosis induction and defects in this signaling pathway lead to chemoresistance. Apoptotic protease activating factor 1 regulates cellular stress evoked by chemotherapeutic agents through facilitating apoptosome assembling but can be degraded by proteasome. This study examined the role of proteasome inhibitor Bortezomib in the cytotoxic effects of Docetaxel on MCF7 cells response and its correlation with Apaf-1 expression level. MTT assay, caspase 3/7 activity assay, propidium iodide staining, adenosine triphosphate and reactive oxygen species amount measurements were utilized to demonstrate the role of Bortezomib in Docetaxel efficacy with and without Apaf-1 overexpressing. Meanwhile, two-dimensional cell migration assay was performed by scratch wound assay. The combination of Docetaxel with Bortezomib was significantly more cytotoxic compared single drug, more effectively delayed cell growth, reduced ATP level and increased ROS production. In Apaf-1 overexpressing, Docetaxel was more efficient in preventing cell migration, however, Docetaxel plus Bortezomib were not significantly effective; and fluorescence images supported the interpretation. Our findings demonstrated MCF7 resistance to Docetaxel is due in part to low Apaf-1 level and Apaf-1 overexpression resulted in the increase of cell susceptibility to Docetaxel stimulus. We assume that proteasome inhibitor may restore apoptotic proteins like Apaf-1 and prevent the degradation of cytosolic cytochrome c released by Docetaxel, consequently triggering intrinsic apoptosis and promoting cancer cell death. Collectively, treating MCF7 breast cells with proteasome inhibitor sensitizes cells to Docetaxel-induced apoptosis and possibly overcomes chemoresistance.

CUDC-101 enhances the chemosensitivity of gemcitabine-treated lymphoma cells

BACKGROUND

The metastasis and recurrence of Non-Hodgkin's lymphoma (NHL) is a major cause of morbidity and mortality. Recent work suggests that drugs capable of targeting epigenetic regulatory mechanisms may be well suited to the treatment of such disease progression.

METHODS

This study was thus designed to evaluate the ability of the novel histone deacetylase (HDAC) inhibitor CUDC-101 to synergize with gemcitabine in order to kill human HUT78 and Pfeiffer NHL cells. To that end, we analyzed the viability of these NHL cells via CCK-8 assay, while the incidence of apoptosis among treated cells was evaluated via Annexin V-FITC/PI staining and by the Western blotting-mediated evaluation of proteins associate with apoptosis and related signaling pathways.

RESULTS

We found that CUDC-101 and gemcitabine interacted synergistically to reduce NHL cell viability and to induce the apoptotic death of these cells via the EGFR/ PI3K/Akt and Erk pathways, which were regulated by HDAC signaling pathways.

CONCLUSION

Together, our results highlight the anti-cancer properties of CUDC-101 alone or in combination with gemcitabine as an approach to inducing the apoptotic death of lymphoma cells in vitro, while also offering insight into the underlying molecular mechanisms governing this activity.

ARHGEF10L Promotes Cervical Tumorigenesis via RhoA-Mediated Signaling

Background

Rho guanine nucleotide exchange factor 10-like protein (ARHGEF10L) is a member of the guanine nucleotide exchange factor family, which regulates Rho GTPase activities, thus contributing to tumorigenesis. Our previous study demonstrated a strong association between the ARHGEF10L gene and the risk of cervical carcinoma. This study investigated the pathogenic role and mechanism of ARHGEF10L in cervical tumors.

Methods

The HeLa cell line, which was derived from cervical carcinoma, was transfected with ARHGEF10L-overexpressing plasmids or anti-ARHGEF10L siRNA. Cell counting kit-8 assays, wound-healing assays, and cell apoptosis assays were performed to investigate the effects of ARHGEF10L on cell activities. A Rho pull-down assay and RNA-sequencing analysis were performed to investigate the pathogenic pathway of ARHGEF10L involvement in cervical tumors.

Results

ARHGEF10L overexpression promoted cell proliferation and migration, reduced cell apoptosis, and induced epithelial-to-mesenchymal transition (EMT) via downregulation of E-cadherin and upregulation of N-cadherin and Slug in transfected HeLa cells. The overexpression of ARHGEF10L also upregulated GTP-RhoA, ROCK1, and phospho-ezrin/radixin/moesin (ERM) expression in HeLa cells. RNA-sequencing analysis detected altered transcription of 31 genes in HeLa cells with ARHGEF10L overexpression. Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) pathway analyses identified significant differences in cyclin-dependent protein serine/threonine kinase activity, cell responses to vitamin A, and Toll-like receptor signaling pathways. Both real-time PCR and Western blotting verified the increased expression of heat shock 70 kDa protein 6 (HSPA6) in ARHGEF10L-overexpressing HeLa cells. Since we reported that ARHGEF10L played a role through RhoA-ROCK1-ERM signaling, an important pathway in tumorigenesis, and stimulated EMT and HSPA6 expression in liver tumors and gastric tumor cells, we suggest that ARHGEF10L is a novel oncogene in many tumors.

Report of a rare case of congenital mitral valve prolapse with chronic kidney disease--reconsidered genotype-phenotypic correlations

Background

Mitral valve prolapse (MVP) is a common cardiovascular disease defined as a late systolic click or mitral valve lobes that move up into the left atrium during ventricular systole, with or without mitral insufficiency. Dachsous catherin‐related 1 (DCHS1) is one of the two known pathogenic genes associated with MVP. However, there is little information about the renal dysfunction caused by MVP and DCHS1 mutations.

Methods

We analyzed the genetic etiology in a rare case of 9‐year‐old boy affected by chronic renal failure with MVP. Subsequently, we constructed stable cell lines overexpressing wild‐type DCHS1 or mutant DCHS1 (c.8309G>A, p.R2770Q) to evaluate the influence of the DCHS1 mutation on the proliferation, apoptosis, and autophagy.

Results

Complete exome sequencing and pedigree verification revealed a mutation p.R2770Q (c.8309G>A) in exon 21 of the DCHS1 gene carried by the patient, which may affect the DNA binding. No such mutation was detected in his parents, indicating that this was a new mutation. Potential functional impact of sequence variants was predicted using in silico prediction programs including SIFT, Polyphen2, and Condel. This variant was determined to be a pathogenic mutation that has not been reported elsewhere. Subsequently, we used a stable DCHS1 gene‐mutated HK‐2 cell line to analyse proliferation, apoptosis, and autophagy, showed that kidney volume decreased with increasing cell death associated with a reduced proliferation.

Conclusions

Our analysis revealed a heterozygous variation of DCHS1 in a child with MVP. Our observations highlight previously unrecognized phenotypes of the currently recognized MVP genotype, including distinct chronic renal failure.

Pancreatic cancer cell apoptosis is induced by a proteoglycan extracted from Ganoderma lucidum

The Traditional Chinese Medicine, Ganoderma lucidum, has been widely used for its immunity-related and anti-cancer effects. Fudan-Yueyang-Ganoderma lucidum (FYGL) is a proteoglycan, extracted from Ganoderma lucidum, that has shown safe anti-diabetic activity in vivo. The present study demonstrated that FYGL could selectively inhibit the viability of PANC-1 and BxPC-3 pancreatic cancer cells in a dose dependent manner, but not in Mia PaCa-2 pancreatic cancer cells and HepG2 liver cancer cells. In addition, FYGL could inhibit migration and colony formation, and promote apoptosis in PANC-1 cells, but not in Mia PaCa-2 cells. Further investigation into the underlying mechanism revealed that FYGL could inhibit the expression level of the Bcl-2 protein in PANC-1 cells, but not in Mia PaCa-2 cells, leading to an increase in reactive oxygen species (ROS) and a reduction in the mitochondrial membrane potential and cell apoptosis. The increased ROS also promoted the formation of autophagosomes, along with an increase in the microtubule-associated protein light chain 3 II/I ratio. However, FYGL halted autophagy by preventing the autophagosomes from entering the lysosomes. The inhibition of autophagy increased the accumulation of defective mitochondria, as well as the production of ROS. Taken together, the processes of ROS regulation and autophagy inhibition promoted apoptosis of PANC-1 cells through the caspase-3/cleaved caspase-3 cascade. These results indicated that FYGL could be potentially used as an anti-cancer agent in the treatment of pancreatic cancer.

Design, Synthesis, In vitro and In silico Evaluation of New Hydrazonebased Antitumor Agents as Potent Akt Inhibitors

Background:

Akt is overexpressed or activated in a variety of human cancers, including gliomas, lung, breast, ovarian, gastric and pancreatic carcinomas. Akt inhibition leads to the induction of apoptosis and inhibition of tumor growth and therefore extensive efforts have been devoted to the discovery of potent antitumor drugs targeting Akt.

Objectives:

The objective of this work was to identify potent anticancer agents targeting Akt.

Methods:

New hydrazone derivatives were synthesized and investigated for their cytotoxic effects on 5RP7 H-ras oncogene transformed rat embryonic fibroblast and L929 mouse embryonic fibroblast cell lines. Besides, the apoptotic effects of the most active compounds on 5RP7 cell line were evaluated using flow cytometry. Their Akt inhibitory effects were also investigated using a colorimetric assay. In silico docking and Absorption, Distribution, Metabolism and Excretion (ADME) studies were also performed using Schrödinger’s Maestro molecular modeling package.

Results and Discussion:

Compounds 3a, 3d, 3g and 3j were found to be effective on 5RP7 cells (with IC50 values of <0.97, <0.97, 1.13±0.06 and <0.97 μg/mL, respectively) when compared with cisplatin (IC50= 1.87±0.15 μg/mL). It was determined that these four compounds significantly induced apoptosis in 5RP7 cell line. Among them, N'-benzylidene-2-[(4-(4-methoxyphenyl)pyrimidin- 2-yl)thio]acetohydrazide (3g) significantly inhibited Akt (IC50= 0.5±0.08 μg/mL) when compared with GSK690693 (IC50= 0.6±0.05 μg/mL). Docking studies suggested that compound 3g showed good affinity to the active site of Akt (PDB code: 2JDO). According to in silico ADME studies, the compound also complies with Lipinski's rule of five and Jorgensen's rule of three.

Conclusion:

Compound 3g stands out as a potential orally bioavailable cytotoxic agent and apoptosis inducer targeting Akt.

A new series of benzoxazole-based SIRT1 modulators for targeted therapy of non-small-cell lung cancer

In an attempt to identify potential anticancer agents for non-small-cell lung cancer (NSCLC) targeting sirtuin 1 (SIRT1), the synthesis of a new series of benzoxazoles (3a - i) was carried out through a facile and versatile synthetic route. The compounds were evaluated for their cytotoxic effects on A549 human lung adenocarcinoma and NIH/3T3 mouse embryonic fibroblast cells using the MTT assay. 2-[(5-Nitro-1H-benzimidazol-2-yl)thio]-N-(2-methylbenzoxazol-5-yl)acetamide (3e) and 2-[(5-chloro-1H-benzimidazol-2-yl)thio]-N-(2-methylbenzoxazol-5-yl)acetamide (3g) were the most potent and selective anticancer agents in this series against the A549 cell line, with IC₅₀ values of 46.66 ± 11.54 and 55.00 ± 5.00 µM, respectively. The flow cytometry-based apoptosis detection assay was performed to determine their effects on apoptosis in A549 cells. Both compounds induced apoptosis in a dose-dependent manner. The effects of compounds 3e and 3g on SIRT1 activity were determined. On the basis of in vitro studies, it was observed that compound 3g caused a significant decrease in SIRT1 levels in a dose-dependent manner, whereas compound 3e increased the SIRT1 levels. According to molecular docking studies, the substantial alteration in the type of action could be attributed to the difference between the interactions of compounds 3e and 3g with the same residues in the active site of SIRT1 (PDB code: 4IG9). On the basis of in silico ADME (absorption, distribution, metabolism, and excretion) studies, these compounds are predicted to possess favorable ADME profiles. According to the in vitro and in silico studies, compounds 3e and 3g, small-molecule SIRT1 modulators, were identified as potential orally bioavailable anticancer agents for the targeted therapy of NSCLC.

Suppression of autophagy facilitates hydrogen gas-mediated lung cancer cell apoptosis

Our previous study found that hydrogen gas (H₂) could efficiently inhibit lung cancer progression; however, the underlying mechanisms still remains to be elucidated. The present study aimed to explore the roles of H₂ in lung cancer cell autophagy, and reveal the effects of autophagy on H₂-mediated lung cancer cell apoptosis and the underlying mechanisms. The expression levels of proteins associated with cell apoptosis and autophagy were detected using western blot analysis. Cell autophagy was inhibited by 3-methyladenine treatment or Beclin1 downregulation, while rapamycin was used to induce autophagy. Cell growth and apoptosis were detected using the Cell Counting Kit-8 and flow cytometry assays, respectively. The results demonstrated that cell apoptosis and autophagy were significantly enhanced in the A549 and H1975 lung cancer cell lines treated with H₂. However, autophagy enhancement weakened H₂ roles in promoting cell apoptosis and vice versa. In addition, it was found that H₂ treatment induced marked decreases in the protein expression levels of phosphorylated STAT3 and Bcl2, and overexpression of STAT3 abolished H₂ roles in promoting cell apoptosis and autophagy. Overall, the present study revealed that H₂ can promote lung cancer cell apoptosis and autophagy via inhibiting the activation of STAT3/Bcl2 signaling and suppression of autophagy can enhance H₂ roles in promoting lung cancer cell apoptosis.

Punicalagin Regulates Apoptosis-Autophagy Switch via Modulation of Annexin A1 in Colorectal Cancer

Punicalagin (PU), a polyphenol extracted from pomegranate (Punica granatum) husk is proven to have anti-cancer effects on different types of cancer including colorectal cancer (CRC). Its role in modulating endogenous protein as a means of eliciting its anti-cancer effects, however, has not been explored to date. Hence, this study aimed to investigate the role of PU in modulating the interplay between apoptosis and autophagy by regulating Annexin A1 (Anx-A1) expression in HCT 116 colorectal adenocarcinoma cells. In the study, selective cytotoxicity, pro-apoptotic, autophagic and Anx-A1 downregulating properties of PU were shown which indicate therapeutic potential that this polyphenol has against CRC. Autophagy flux analysis via flow cytometry showed significant autophagosomes degradation in treated cells, proving the involvement of autophagy. Proteome profiling of 35 different proteins in the presence and absence of Anx-A1 antagonists in PU-treated cells demonstrated a complex interplay that happens between apoptosis and autophagy that suggests the possible simultaneous induction and inhibition of these two cell death mechanisms by PU. Overall, this study suggests that PU induces autophagy while maintaining basal level of apoptosis as the main mechanisms of cytotoxicity via the modulation of Anx-A1 expression in HCT 116 cells, and thus has a promising translational potential.

Pristine C60 Fullerene Nanoparticles Ameliorate Hyperglycemia-Induced Disturbances via Modulation of Apoptosis and Autophagy Flux

Diabetes mellitus is a prevalent metabolic disorder associated with multiple complications including neuropathy, memory loss and cognitive decline. Despite a long history of studies on diabetic complications, there are no effective therapeutic strategies for neuroprotection in diabetes. Hyperglycemia-induced imbalance in programmed cell death could initiate a decline in neural tissue cells viability. Various nanomaterials can induce either cell death or cell survival dependent on the type and surface features. Pristine C₆₀ fullerene is a nontoxic nanomaterial, which exhibits antioxidant and cytoprotective properties. However, the precise molecular mechanism with which the C₆₀ nanoparticle exerts cytoprotective effect in diabetic subjects has not yet been fully addressed. Thus, this study aimed to determine whether C₆₀ fullerene prevents oxidative stress impairment and to explore the effects of C₆₀ fullerene on apoptosis and autophagy in diabetes mellitus to clarify its potential mechanisms. These effects have been examined for olive oil extracted C₆₀ fullerene on the hippocampus of STZ diabetic rats. Up-regulation of Caspase-3, Beclin-1 and oxidative stress indexes and down-regulation of Bcl-2 were observed in the brain of STZ-diabetic rats. The exposure to C₆₀ fullerene for a period of 12 weeks ameliorate redox imbalance, hyperglycemia-induced disturbances in apoptosis and autophagy flux via modulation of Caspase-3, Bcl-2, Beclin-1 and LC3I/II contents. Furthermore, C₆₀ fullerene ameliorated the LC3I/II ratio and prevented extremely increased autophagy flux. Contrarily, pristine C₆₀ fullerene had no modulatory effect on all studied apoptotic and autophagy markers in non-diabetic groups. Therefore, oil extracted C₆₀ fullerene exhibits cytoprotective effect in hyperglycemia-stressed hippocampal cells. The presented results confirm that pristine C₆₀ fullerene nanoparticles can protect hippocampal cells against hyperglycemic stress via anti-oxidant, anti-apoptotic effects and amelioration of autophagy flux. Moreover, C₆₀ fullerene regulates a balance of autophagy via BCL-2/Beclin-1 reciprocal expression that could prevent functional disturbances in hippocampus.

Melanoma stem cell maintenance and chemo-resistance are mediated by CD133 signal to PI3K-dependent pathways

Melanoma stem cells (MSCs) are characterized by their unique cell surface proteins and aberrant signaling pathways. These stemness properties are either in a causal or consequential relationship to melanoma progression, treatment resistance and recurrence. The functional analysis of CD133⁺ and CD133^- cells in vitro and in vivo revealed that melanoma progression and treatment resistance are the consequences of CD133 signal to PI3K pathway. CD133 signal to PI3K pathway drives two downstream pathways, the PI3K/Akt/MDM2 and the PI3K/Akt/MKP-1 pathways. Activation of PI3K/Akt/MDM2 pathway results in the destabilization of p53 protein, while the activation of PI3K/Akt/MKP-1 pathway results in the inhibition of mitogen-activated protein kinases (MAPKs) JNK and p38. Activation of both pathways leads to the inhibition of fotemustine-induced apoptosis. Thus, the disruption of CD133 signal to PI3K pathway is essential to overcome Melanoma resistance to fotemustine. The pre-clinical verification of in vitro data using xenograft mouse model of MSCs confirmed the clinical relevance of CD133 signal as a therapeutic target for melanoma treatment. In conclusion, our study provides an insight into the mechanisms regulating MSCs growth and chemo-resistance and suggested a clinically relevant approach for melanoma treatment.

Anticancer and Antiangiogenic Activities of Novel α-Mangostin Glycosides in Human Hepatocellular Carcinoma Cells via Downregulation of c-Met and HIF-1α

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and is a leading cause of cancer-related death worldwide. Therefore, exploring effective anticancer agents and their modes of action is essential for the prevention and treatment of HCC. Glycosylation can significantly improve the physicochemical and biological properties of small molecules, such as high solubility, stability increase, and lower toxicity. In the present study, for the first time, we evaluated the anticancer and antiangiogenic activities of α-mangostin-3-O-β-D-2-deoxyglucopyranoside (Man-3DG) and α-mangostin 6-O-β-D-2-deoxyglucopyranoside (Man-6DG), glycosides of α-mangostin, against human HCC cells. Our results demonstrated that Man-3DG and Man-6DG significantly suppressed the growth of three different HCC cells (Hep3B, Huh7, and HepG2) as well as the migration of Hep3B cells. Furthermore, they induced cell cycle arrest in the G0/G1 phases and apoptotic cell death by regulating apoptosis-related proteins of mitochondria in Hep3B cells. Noticeably, Man-3DG and Man-6DG also caused autophagy, while co-treatment of the α-mangostin glycosides with an autophagy inhibitor 3-MA enhanced the inhibitory effect on Hep3B cell growth in comparison to single agent treatment. Moreover, Man-3DG and Man-6DG inhibited the c-Met signaling pathway that plays a critical role in the pathogenesis of HCC. Furthermore, the α-mangostin glycosides decreased Hep3B cell-induced angiogenesis in vitro through the downregulation of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF). Notably, Man-6DG more effectively inhibited the growth, tumorsphere formation, and expression of cancer stemness regulators compared to α-mangostin and Man-3DG in 3D spheroid-cultured Hep3B cells. These findings suggest that the α-mangostin glycosides might be promising anticancer agents for HCC treatment with superior pharmacological properties than the parent molecule α-mangostin.

Elevated histone H3 citrullination is associated with increased Beclin1 expression in HBV-related hepatocellular carcinoma

Citrullinated histone H3 (H3Cit) is the product of the conversion of peptidylarginine to citrulline in histone H3. We evaluated the H3Cit level in hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) tissues and assessed its association with Beclin1 messenger RNA (mRNA) (a key autophagic regulator). The level of H3Cit was detected by a capture enzyme-linked immunosorbent assay, while Beclin1 mRNA was determined by real-time polymerase chain reaction in 80 HBV-related patients with HCC. We found that the mean level of H3Cit was 72.25 ng/mg in HCC and 44.02 ng/mg in nontumor tissues. The mean HCC/nontumor ratio of Beclin1 mRNA was higher (0.096) in tumor samples than in nontumor specimens (0.056). Specifically, Beclin1 mRNA was elevated in 51 HCC cases (63.75%) and decreased in 29 cases (36.25%). Moreover, the levels of H3Cit and Beclin1 mRNA were significantly associated with vascular invasion and serum AFP levels. A shorter survival (19 months) was associated with a high H3Cit level. We also found increased levels of Beclin1 mRNA in the H3Cit (high) group compared with the H3Cit (low) group. The results implied that elevated histone H3 citrullination is associated with increased Beclin1 expression during the development of HBV-related HCC.

PFKFB3 Inhibition Attenuates Oxaliplatin-Induced Autophagy and Enhances Its Cytotoxicity in Colon Cancer Cells

6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase isoform 3 (PFKFB3), a glycolytic enzyme highly expressed in cancer cells, has been reported to participate in regulating metabolism, angiogenesis, and autophagy. Although anti-cancer drug oxaliplatin (Oxa) effectively inhibits cell proliferation and induces apoptosis, the growing resistance and side-effects make it urgent to improve the therapeutic strategy of Oxa. Although Oxa induces the autophagy process, the role of PFKFB3 in this process remains unknown. In addition, whether PFKFB3 affects the cytotoxicity of Oxa has not been investigated. Here, we show that Oxa-inhibited cell proliferation and migration concomitant with the induction of apoptosis and autophagy in SW480 cells. Both inhibition of autophagy by small molecule inhibitors and siRNA modification decreased the cell viability loss and apoptosis induced by Oxa. Utilizing quantitative PCR and immunoblotting, we observed that Oxa increased PFKFB3 expression in a time- and dose-dependent manner. Meanwhile, suppression of PFKFB3 attenuated both the basal and Oxa-induced autophagy, by monitoring the autophagic flux and phosphorylated-Ulk1, which play essential roles in autophagy initiation. Moreover, PFKFB3 inhibition further inhibited the cell proliferation/migration, and cell viability decreased by Oxa. Collectively, the presented data demonstrated that PFKFB3 inhibition attenuated Oxa-induced autophagy and enhanced its cytotoxicity in colorectal cancer cells.

Ethanol extract of Chrysanthemum zawadskii Herbich induces autophagy and apoptosis in mouse colon cancer cells through the regulation of reactive oxygen species

Background

Recent research has suggested that autophagy can provide a better mechanism for inducing cell death than current therapeutic strategies. This study investigated the effects of using an ethanol extract of Chrysanthemum zawadskii Herbich (ECZ) to induce apoptosis and autophagy associated with reliable signal pathways in mouse colon cancer CT-26 cells.

Methods

Using ECZ on mouse colon cancer CT-26 cells, cell viability, annexin V/propidium iodide staining, acridine orange staining, reactive oxygen species (ROS) and western blotting were assayed.

Results

ECZ exhibited cytotoxicity in CT-26 cells in a dose-dependent manner. ECZ induced apoptosis was confirmed by caspase-3 activation, poly (ADP-ribose) polymerase cleavage, and increased production of reactive oxygen species (ROS). Furthermore, it was shown that ECZ induced autophagy via the increased conversion of microtubule-associated protein 1 light chain 3II, the degradation of p62, and the formation of acidic vesicular organelles. The inhibition of ROS production by N-Acetyl-L-cysteine resulted in reduced ECZ-induced apoptosis and autophagy. Furthermore, the inhibition of autophagy by 3-methyladenine resulted in enhanced ECZ-induced apoptosis via increased ROS generation.

Conclusion

These findings confirmed that ECZ induced ROS-mediated autophagy and apoptosis in colon cancer cells. Therefore, ECZ may serve as a novel potential chemotherapeutic candidate for colon cancer.

Supercritical CO2 fluid extraction of croton crassifolius Geisel root: Chemical composition and anti-proliferative, autophagic, apoptosis-inducing, and related molecular effects on A549 tumour cells

BACKGROUND

The use of plant essential oils as pharmaceuticals is a fast-growing market especially in China. Throughout the 20th century, a rapid increase took place in the use of many essential oil-derived products in the medicinal industry as nutraceuticals, medicinal supplements, and pharmaceuticals.

PURPOSE

The objective of this study was to explore the chemical composition of Croton crassifolius essential oil as well as its potential anti-tumour properties and related anti-proliferative, autophagic, and apoptosis-inducing effects.

METHODS

Supercritical CO₂ fluid extraction technology was used to extract CCEO and the chemical constituents of the essential oil were identified by comparing the retention indices and mass spectra data taken from the NIST library with those calculated based on the C7-C40 n-alkanes standard. The cytotoxic activity and anti-proliferative effects of CCEO were evaluated against five cancer cell lines and one normal human cell line via CCK-8 assays. In addition, flow cytometry was used to detect cell cycle arrest. The efficacy of CCEO treatments in controlling cancer cell proliferation was assessed by cell cycle analysis, clonal formation assays, RT-qPCR, and western blot analysis. Autophagic and apoptosis-inducing effects of oils and the associated molecular mechanisms were assessed by flow cytometry, cell staining, reactive oxygen species assays, RT-qPCR, and western blot analysis.

CONCLUSION

Forty compounds representing 92.90% of the total oil were identified in CCEO. The results showed that CCEO exerted a measurable selectivity for cancer cell lines, especially for A549 with the lowest IC₅₀ value of 25.00 ± 1.62 μg/mL. Assessment of the anti-proliferative effects of CCEO on A549 cells showed that the oil inhibited cell proliferation and colony formation in a dose- and time-dependent manner. Investigation of the molecular mechanisms of cell cycle regulation confirmed that the oil arrested A549 cells in G2/M phase by decreasing the expression of cyclin B1-CDK1 and cyclin A-CDK1 and increasing the expression of cyclin-dependent kinase inhibitor (CKI) P21 at both the transcriptional and translational levels. Autophagy staining assays and western blot analysis revealed that CCEO promoted the formation of autophagic vacuoles in A549 cells and increased the expression of autophagy-related proteins beclin-1 and LC3-II in a dose-dependent manner. A series of apoptosis analyses indicated that CCEO induces apoptosis through a mitochondria-mediated intrinsic pathway. This study revealed that CCEO is a promising candidate for development into an anti-tumour drug of the future.

Potential proapoptotic phytochemical agents for the treatment and prevention of colorectal cancer

Colorectal cancer (CRC) is one of the leading causes of mortality among men and women. Chemo-resistance, adverse effects and disease recurrence are major challenges in the development of effective cancer therapeutics. Substantial literature on this subject highlights that populations consuming diets rich in fibers, fruits and vegetables have a significantly reduced incidence rate of CRC. This chemo-preventive effect is primarily associated with the presence of phytochemicals in the dietary components. Plant-derived chemical agents act as a prominent source of novel compounds for drug discovery. Phytochemicals have been the focus of an increasing number of studies due to their ability to modulate carcinogenic processes through the alteration of multiple cancer cell survival pathways. Despite promising results from experimental studies, only a limited number of phytochemicals have entered into clinical trials. The purpose of the current review is to compile previously published pre-clinical and clinical evidence of phytochemicals in cases of CRC. A PubMed, Google Scholar and Science Direct search was performed for relevant articles published between 2008-2018 using the following key terms: 'Phytochemicals with colorectal cancers', 'apoptosis', 'cell cycle', 'reactive oxygen species' and 'clinical anticancer activities'. The present review may aid in identifying the most investigated phytochemicals in CRC cells, and due to the limited number of studies that make it from the laboratory bench to clinical trial stage, may provide a novel foundation for future research.

Mechanism of Resistance in Gastrointestinal Stromal Tumors

Imatinib has revolutionized the treatment of GIST since this drug is able to inhibit tumoral growth by blocking the activity of receptor tyrosine kinases, KIT or PDGFRA, that in these tumors are constitutively activated because of the presence of mutations that alters their catalytic activity. However, despite this enormous improvement in the RFS and OS and in the quality of life of GIST patients, imatinib is not able to eradicate the disease: recurrences occur and acquired resistance is a common event which develops during targeted treatments. Several mechanisms have been demonstrated to be responsible for tumoral growth reactivation which is due to the reactivation of the altered KIT/PDGFRA receptors, no more blocked by the drug. Secondary point mutations are generally observed in the regrowing tumors, and it has been demonstrated that they alter the architectural structure of the site in which the interaction between the drug and the receptor happens. Other mechanisms causing drug resistance have been investigated, indicating that many aspects need to be still explicated and fully understood in order to define a strategy able to fight definitively GIST growth.

Luteolin suppresses tumor proliferation through inducing apoptosis and autophagy via MAPK activation in glioma

PURPOSE

Glioma is a malignant tumor that originates in the brain and spine and is difficult to be completely removed. Though glioma patients receive active treatment, the survival rate is still poor. Therefore, it is urgent to discover a new medicine to treat glioma patients in order to improve the survival rate. In this study, we explored the anticancer effect and the potential mechanism of luteolin on glioma in vitro.

MATERIALS AND METHODS

Cell viability was determined by Cell Counting Kit-8 (CCK-8) assay. Fluorescent microscopy and flow cytometry analysis were used to determine the cellular apoptosis. Western blot analysis was performed to explore the changes in protein expression. Quantitative reverse transcription-PCR (qRT-PCR) analysis was utilized to evaluate the expression level of the tumor suppressor miR-124-3p.

RESULTS

CCK-8 assays indicated that luteolin significantly inhibited glioma cell proliferation in a time- and dose-dependent manner. Fluorescent microscopy and flow cytometry analysis confirmed that luteolin induced glioma cell apoptosis. Western blot analysis showed that luteolin induced cellular apoptosis in glioma cells via MAPK activation (JNK, ERK, and p38). Luteolin stimulated the death receptor (FADD) to regulate the apoptosis proteins (Caspase-8, Caspase-3, and PARP). Luteolin increased the expression levels of LC3B II/I and downregulated the level of p62 that promotes cell autophagy. Finally, qRT-PCR confirmed that luteolin upregulated the expression levels of miR-124-3p.

CONCLUSION

These findings illustrate that luteolin may be a potential drug for glioma treatment.

Integrative analysis of Paneth cell proteomic and transcriptomic data from intestinal organoids reveals functional processes dependent on autophagy

Paneth cells are key epithelial cells that provide an antimicrobial barrier and maintain integrity of the small-intestinal stem cell niche. Paneth cell abnormalities are unfortunately detrimental to gut health and are often associated with digestive pathologies such as Crohn's disease or infections. Similar alterations are observed in individuals with impaired autophagy, a process that recycles cellular components. The direct effect of autophagy impairment on Paneth cells has not been analysed. To investigate this, we generated a mouse model lacking Atg16l1 specifically in intestinal epithelial cells, making these cells impaired in autophagy. Using three-dimensional intestinal organoids enriched for Paneth cells, we compared the proteomic profiles of wild-type and autophagy-impaired organoids. We used an integrated computational approach combining protein-protein interaction networks, autophagy-targeted proteins and functional information to identify the mechanistic link between autophagy impairment and disrupted pathways. Of the 284 altered proteins, 198 (70%) were more abundant in autophagy-impaired organoids, suggesting reduced protein degradation. Interestingly, these differentially abundant proteins comprised 116 proteins (41%) that are predicted targets of the selective autophagy proteins p62, LC3 and ATG16L1. Our integrative analysis revealed autophagy-mediated mechanisms that degrade key proteins in Paneth cell functions, such as exocytosis, apoptosis and DNA damage repair. Transcriptomic profiling of additional organoids confirmed that 90% of the observed changes upon autophagy alteration have effects at the protein level, not on gene expression. We performed further validation experiments showing differential lysozyme secretion, confirming our computationally inferred downregulation of exocytosis. Our observations could explain how protein-level alterations affect Paneth cell homeostatic functions upon autophagy impairment.This article has an associated First Person interview with the joint first authors of the paper.

Targeting cholesterol metabolism in glioblastoma: a new therapeutic approach in cancer therapy

Glioblastoma multiforme (GBM) is the most aggressive malignant brain tumor known with a poor survival rate despite current advances in the field of cancer. Additional research into the pathophysiology of GBM is urgently needed given the devastating nature of this disease. Recent studies have revealed the unique cellular physiology of GBM cells as compared with healthy astrocytes. Intriguingly, GBM cells are incapable of de novo cholesterol synthesis via the mevalonate pathway. Thus, the survival of GBM cells depends on cholesterol uptake via low-density lipoprotein receptors (LDLRs) in the form of apolipoprotein-E-containing lipoproteins and ATP-binding cassette transporter A1 (ABCA1) that efflux surplus cholesterol out of cells. Liver X receptors regulate intracellular cholesterol levels in neurons and healthy astrocytes through changes in the expression of LDLR and ABCA1 in response to cholesterol and its derivatives. In GBM cells, due to the dysregulation of this surveillance pathway, there is an accumulation of intracellular cholesterol. Furthermore, intracellular cholesterol regulates temozolomide-induced cell death in glioblastoma cells via accumulation and activation of death receptor 5 in plasma membrane lipid rafts. The mevalonate pathway and autophagy flux are also fundamentally related with implications for cell health and death. Thus, via cholesterol metabolism, the mevalonate pathway may be a crucial player in the pathogenesis and treatment of GBM where our current understanding is still lacking. Targeting cholesterol metabolism in GBM may hold promise as a novel adjunctive clinical therapy for this devastating cancer.

Analysis of Comparative Proteomic and Potent Targets of Peniciketal A in Human Acute Monocytic Leukemia

BACKGROUND

Peniciketal A (Pe-A), a spiroketal compound, shows potent anticancer activities in human acute monocytic leukemia. However, the detailed mechanisms and potent targets of Pe-A remain largely unexplored. Here, we investigated the differentially expressed proteins between the Pe-A-treated group and the control group on human acute monocytic leukemia cell line THP-1.

METHODS

The DEPs were analyzed by the liquid chromatography-tandem mass spectrometry (LC-MS/MS) with TMT label. The function and feature of the identified proteins were analyzed by the bioinformatic analysis. Western blotting was used to evaluate protein expression.

RESULTS

The DEPs were primarily sub located in the cytoplasm and the nucleus by regulating 21 pathways enriched through the Kyoto Encyclopedia of Genes and Genomes (KEGG). Moreover, we preliminarily demonstrated that glucose-6-phosphate 1-dehydrogenase (G6PD), prolow-density lipoprotein receptor-related protein 1 (LRP1) and Calreticulin (CALR) might be the potent targets of Pe-A on death induction of THP-1 cells.

CONCLUSION

Collectively, this study not only provides a global proteomic profile as the supplementary data of our previous studies but also provides interesting information that Pe-A may exert more bio-activities.

Role of apoptotic, autophagic and senescence pathways in minor salivary gland adenoid cystic carcinoma

Background

Adenoid cystic carcinoma (ACC) is a salivary gland malignancy with poor long-term survival, which warrants studies aimed at clarifying the pathogenesis of this disease in order to widen the scope of therapeutic options currently available. Alterations in regulatory mechanisms relating to vascular support, cell death and autophagy are important pathways for tumor growth in cancer. Thus, the present study aimed to access vascular supply, apoptosis, autophagy and cell senescence in ACC of minor salivary glands.

Methods

We analyzed 25 cases of minor salivary gland ACC by immunohistochemistry using anti-CD34, anti-CD105, anti-D2–40, anti-Bax, anti-Bcl-2, anti-Beclin-1, anti-LC3B, anti-p21 and anti-p16.

Results

Microvessel density was low and based on anti-CD34, anti-CD105 and anti-D2–40 immunostaining. There was positivity for anti-CD34, anti-Bcl-2, anti-Beclin, anti-LC3B and anti-p21 and a positive correlation between Bcl-2 and Beclin (p = 0.014).

Conclusions

Our results showed that ACC does not depend on neo-angiogenesis and is probably associated to anti-apoptotic, autophagic and anti-senescence events.

Curcumin and Solid Lipid Curcumin Particles Induce Autophagy, but Inhibit Mitophagy and the PI3K-Akt/mTOR Pathway in Cultured Glioblastoma Cells

Autophagy and the (PI3K-Akt/mTOR) signaling pathway play significant roles in glioblastoma multiforme (GBM) cell death and survival. Curcumin (Cur) has been reported to prevent several cancers, including GBM. However, the poor solubility and limited bioavailability of natural Cur limits its application in preventing GBM growth. Previously, we have shown the greater apoptotic and anti-carcinogenic effects of solid lipid Cur particles (SLCP) than natural Cur in cultured GBM cells. Here, we compared the autophagic responses on cultured U-87MG, GL261, F98, C6-glioma, and N2a cells after treatment with Cur or SLCP (25 µM for 24 h). Different autophagy, mitophagy, and chaperone-mediated autophagy (CMA) markers, along with the PI3K-AKkt/mTOR signaling pathway, and the number of autophagy vacuoles were investigated after treatment with Cur and or SLCP. We observed increased levels of autophagy and decreased levels of mitophagy markers, along with inhibition of the PI3K-Akt/mTOR pathway after treatments with Cur or SLCP. Cell survival markers were downregulated, and cell death markers were upregulated after these treatments. We found greater effects in the case of SCLP-treated cells in comparison to Cur. Given that fewer effects were observed on C-6 glioma and N2a cells. Our results suggest that SLCP could be a safe and effective means of therapeutically modulating autophagy in GBM cells.

Tocotrienols Modulate a Life or Death Decision in Cancers

Malignancy often arises from sophisticated defects in the intricate molecular mechanisms of cells, rendering a complicated molecular ground to effectively target cancers. Resistance toward cell death and enhancement of cell survival are the common adaptations in cancer due to its infinite proliferative capacity. Existing cancer treatment strategies that target a single molecular pathway or cancer hallmark fail to fully resolve the problem. Hence, multitargeted anticancer agents that can concurrently target cell death and survival pathways are seen as a promising alternative to treat cancer. Tocotrienols, a minor constituent of the vitamin E family that have previously been reported to induce various cell death mechanisms and target several key survival pathways, could be an effective anticancer agent. This review puts forward the potential application of tocotrienols as an anticancer treatment from a perspective of influencing the life or death decision of cancer cells. The cell death mechanisms elicited by tocotrienols, particularly apoptosis and autophagy, are highlighted. The influences of several cell survival signaling pathways in shaping cancer cell death, particularly NF-κB, PI3K/Akt, MAPK, and Wnt, are also reviewed. This review may stimulate further mechanistic researches and foster clinical applications of tocotrienols via rational drug designs.

Notoamide-type alkaloid induced apoptosis and autophagyviaa P38/JNK signaling pathway in hepatocellular carcinoma cells

Eleven notoamides including four new congeners were isolated fromAspergillus ochraceus. Notoamide G inhibited the viability of hepatocellular carcinoma cell lines by regulation of apoptosis and autophagy through P38/JNK signaling pathway.

Antitumor activity of the novel HDAC inhibitor CUDC-101 combined with gemcitabine in pancreatic cancer

Histone deacetylase (HDAC) is overexpressed in multiple cancers including pancreatic cancer (PC). However, the effects of histone deacetylase inhibitor (HDACi) on apoptosis and epithelial-mesenchymal transition (EMT) differ in various cancers. In this study, we aimed to investigate the anti-tumor effects of a novel multitargets HDACi, CUDC-101, combined with gemcitabine in PC cell lines. In vitro, we found that Co-treatment with CUDC-101 and gemcitabine results in greater levels of apoptosis and significantly inhibited cell proliferation on PC cells. In addition, CUDC-101 enhanced gemcitabine-induced apoptosis via inhibited PI3K/Akt/mTOR and Erk pathway activation, as indicated by the phosphorylation status of Akt, 4EBP1, S6 and Erk. We also found that co-treatment with gemcitabine and CUDC-101 not only synergistically suppressed ability of PC cell migration and invasion, but also synergistically inhibited EMT signaling pathway through modulation of cadherin, vimentin and transcription factors Snail, Slug and MMP-9. In vivo, the co-treatment group showed a significant anti-tumor function in the growth of xenograft tumors. Overall, combination of CUDC-101 and gemcitabine significantly increased anti-tumor activities compared with single drug alone, thus supporting a further evaluation of combination treatment for PC. Accordingly, it provides a rationale to investigate the combination of gemcitabine and CUDC-101 as a potential therapeutic strategy for PC.