Beclin-1 expression is retained in high-grade serous ovarian cancer yet is not essential for autophagy induction in vitro

Boosting immune response against cervical cancer: A combined approach using oncolytic virus and targeted therapies

BACKGROUND

Cervical cancer remains a primary reason for cancer malignancy among women worldwide, primarily due to human papillomavirus (HPV) strains HPV16 and HPV18. Despite having access to vaccines, there are few treatment options for advanced or recurring cases. This research investigates the possibility of using Newcastle disease virus (NDV) along with Everolimus (EVE) and Beclin-1 (BEC) to improve immune reactions and decrease tumor development in an experimental model of HPV-related cervical cancer.

METHODS

A mouse model for cervical cancer was created by utilizing HPV16 E6/E7-expressing TC-1 cells in C57BL/6 mice. The mice underwent treatment with NDV, EVE, BEC, or various combinations of these therapies. Tumor progression was monitored, evaluated immune responses by measuring cytokine levels (including IL-4, IFN-γ, and IL-12), and investigated the presence of CD8 + T cells within the tumors. Additionally, survival rates were monitored throughout the study.

RESULTS

The synergy of NDV, EVE, and BEC led to a remarkable decrease in tumor growth, achieving reductions of as much as 70% when compared to monotherapies. Additionally, our combination therapy elicited strong immune reactions, evidenced by increased concentrations of IL-4, IFN-γ, and IL-12, along with enhanced infiltration of CD8 + T cells into the tumors. Mice that were subjected to this Triple therapy exhibited better survival rates than those in other treatment categories.

CONCLUSIONS

Our findings highlight the potential to improve outcomes in cervical cancer associated with HPV through a multi-faceted approach incorporating NDV, Everolimus, and Beclin-1. This therapeutic strategy not only hinders tumor growth but also strengthens the immune system's ability to fight against cancer. These results prompt further exploration of this combination in clinical trials, with the goal of offering new treatment avenues for patients who have limited choices.

Netrin signaling mediates survival of dormant epithelial ovarian cancer cells

Dormancy in cancer is a clinical state in which residual disease remains undetectable for a prolonged duration. At a cellular level, rare cancer cells cease proliferation and survive chemotherapy and disseminate disease. We created a suspension culture model of high-grade serous ovarian cancer (HGSOC) dormancy and devised a novel CRISPR screening approach to identify survival genes in this context. In combination with RNA-seq, we discovered the Netrin signaling pathway as critical to dormant HGSOC cell survival. We demonstrate that Netrin-1, -3, and its receptors are essential for low level ERK activation to promote survival, and that Netrin activation of ERK is unable to induce proliferation. Deletion of all UNC5 family receptors blocks Netrin signaling in HGSOC cells and compromises viability during the dormancy step of dissemination in xenograft assays. Furthermore, we demonstrate that Netrin-1 and -3 overexpression in HGSOC correlates with poor outcome. Specifically, our experiments reveal that Netrin overexpression elevates cell survival in dormant culture conditions and contributes to greater spread of disease in a xenograft model of abdominal dissemination. This study highlights Netrin signaling as a key mediator HGSOC cancer cell dormancy and metastasis.

Proteomic and Phosphoproteomic Reprogramming in Epithelial Ovarian Cancer Metastasis

Epithelial ovarian cancer (EOC) is a high-risk cancer presenting with heterogeneous tumors. The high incidence of EOC metastasis from primary tumors to nearby tissues and organs is a major driver of EOC lethality. We used cellular models of spheroid formation and readherence to investigate cellular signaling dynamics in each step toward EOC metastasis. In our system, adherent cells model primary tumors, spheroid formation represents the initiation of metastatic spread, and readherent spheroid cells represent secondary tumors. Proteomic and phosphoproteomic analyses show that spheroid cells are hypoxic and show markers for cell cycle arrest. Aurora kinase B abundance and downstream substrate phosphorylation are significantly reduced in spheroids and readherent cells, explaining their cell cycle arrest phenotype. The proteome of readherent cells is most similar to spheroids, yet greater changes in the phosphoproteome show that spheroid cells stimulate Rho-associated kinase 1 (ROCK1)-mediated signaling, which controls cytoskeletal organization. In spheroids, we found significant phosphorylation of ROCK1 substrates that were reduced in both adherent and readherent cells. Application of the ROCK1-specific inhibitor Y-27632 to spheroids increased the rate of readherence and altered spheroid density. The data suggest ROCK1 inhibition increases EOC metastatic potential. We identified novel pathways controlled by Aurora kinase B and ROCK1 as major drivers of metastatic behavior in EOC cells. Our data show that phosphoproteomic reprogramming precedes proteomic changes that characterize spheroid readherence in EOC metastasis.

Friend and foe: the regulation network of ascites components in ovarian cancer progression

The tumor microenvironment (TME) and its complex role in cancer progression have been hotspots of cancer research in recent years. Ascites, which occurs frequently in patients with ovarian cancer especially in advanced stages, represents a unique TME. Malignant ascites contains abundant cellular and acellular components that play important roles in tumorigenesis, growth, metastasis, and chemoresistance of ovarian cancer through complex molecular mechanisms and signaling pathways. As a valuable liquid biopsy sample, ascites fluid is also of great significance for the prognostic analysis of ovarian cancer. The components of ovarian cancer ascites are generally considered to comprise tumor-promoting factors; however, in recent years studies have found that ascites also contains tumor-suppressing factors, raising new perspectives on interactions between ascites and tumors. Malignant ascites directly constitutes the ovarian cancer microenvironment, therefore, the study of its components will aid in the development of new therapeutic strategies. This article reviews the current research on tumor-promoting and tumor-suppressing factors and molecular mechanisms of their actions in ovarian cancer-derived ascites and therapeutic strategies targeting ascites, which may provide references for the development of novel therapeutic targets for ovarian cancer in the future.

The multifaced role and therapeutic regulation of autophagy in ovarian cancer

Ovarian cancer (OC) is one of the tumors that occurs most frequently in women. Autophagy is involved in cell homeostasis, biomolecule recycling, and survival, making it a potential target for anti-tumor drugs. It is worth noting that growing evidence reveals a close link between autophagy and OC. In the context of OC, autophagy demonstrates activity as both a tumor suppressor and a tumor promoter, depending on the context. Autophagy's exact function in OC is greatly reliant on the tumor microenvironment (TME) and other conditions, such as hypoxia, nutritional deficiency, chemotherapy, and so on. However, what can be concluded from different studies is that autophagy-related signaling pathways, especially PI3K/AKT/mTOR axis, increase in advanced stages and malignant phenotype of the disease reduces autophagy and ultimately leads to tumor progression. This study sought to present a thorough understanding of the role of autophagy-related signaling pathways in OC and existing therapies targeting these signaling pathways.

Principles of dormancy evident in high-grade serous ovarian cancer

In cancer, dormancy refers to a clinical state in which microscopic residual disease becomes non-proliferative and is largely refractory to chemotherapy. Dormancy was first described in breast cancer where disease can remain undetected for decades, ultimately leading to relapse and clinical presentation of the original malignancy. A long latency period can be explained by withdrawal from cell proliferation (cellular dormancy), or a balance between proliferation and cell death that retains low levels of residual disease (tumor mass dormancy). Research into cellular dormancy has revealed features that define this state. They include arrest of cell proliferation, altered cellular metabolism, and unique cell dependencies and interactions with the microenvironment. These characteristics can be shared by dormant cells derived from disparate primary disease sites, suggesting common features exist between them.

High-grade serous ovarian cancer (HGSOC) disseminates to locations throughout the abdominal cavity by means of cellular aggregates called spheroids. These growth-arrested and therapy-resistant cells are a strong contributor to disease relapse. In this review, we discuss the similarities and differences between ovarian cancer cells in spheroids and dormant properties reported for other cancer disease sites. This reveals that elements of dormancy, such as cell cycle control mechanisms and changes to metabolism, may be similar across most forms of cellular dormancy. However, HGSOC-specific aspects of spheroid biology, including the extracellular matrix organization and microenvironment, are obligatorily disease site specific. Collectively, our critical review of current literature highlights places where HGSOC cell dormancy may offer a more tractable experimental approach to understand broad principles of cellular dormancy in cancer.

miRNA-Dependent Regulation of AKT1 Phosphorylation

The phosphoinositide-3-kinase (PI3K)/AKT pathway regulates cell survival and is over-activated in most human cancers, including ovarian cancer. Following growth factor stimulation, AKT1 is activated by phosphorylation at T308 and S473. Disruption of the AKT1 signaling pathway is sufficient to inhibit the epithelial-mesenchymal transition in epithelial ovarian cancer (EOC) cells. In metastatic disease, adherent EOC cells transition to a dormant spheroid state, characterized previously by low S473 phosphorylation in AKT1. We confirmed this finding and observed that T308 phosphorylation was yet further reduced in EOC spheroids and that the transition from adherent to spheroid growth is accompanied by significantly increased levels of let-7 miRNAs. We then used mechanistic studies to investigate the impact of let-7 miRNAs on AKT1 phosphorylation status and activity in cells. In growth factor-stimulated HEK 293T cells supplemented with let-7a, we found increased phosphorylation of AKT1 at T308, decreased phosphorylation at S473, and enhanced downstream AKT1 substrate GSK-3β phosphorylation. Let-7b and let-7g also deregulated AKT signaling by rendering AKT1 insensitive to growth factor simulation. We uncovered let-7a-dependent deregulation of PI3K pathway components, including PI3KC2A, PDK1, and RICTOR, that govern AKT1 phosphorylation and activity. Together, our data show a new role for miRNAs in regulating AKT signaling.

Diagnostic and prognostic value of Beclin 1 expression in melanoma: a meta-analysis

Autophagy plays a complicated role in the occurrence and development of cancer. Beclin 1 is a significant autophagy-related protein that plays an essential role in tumorigenesis, but its expression is controversial in melanoma. In this meta-analysis, we searched seven studies involving 638 melanoma patients. PubMed, Web of Science, Google Scholar, Elsevier, and Chinese National Knowledge Infrastructure were used for literature retrieval. The I2 index was used to assess heterogeneity. The expression of Beclin 1 in the primary melanoma group was significantly lower than the non-tumor group tissues (P < 0.01), while higher than the metastatic melanoma group (P < 0.01). Beclin 1 expression status could not distinguish between patients with melanoma by sex (male vs. female), lymph node metastasis (metastasis vs. non-metastasis), melanin deposition (present vs. absent), ulcer formation (present vs. absent), tumor necrosis status (present vs. absent), and Breslow thickness (<1.5 mm vs. ≥1.5 mm) for the subgroups (all P values > 0.05). Different expression intensities of Beclin 1 did not affect the overall survival and disease-free survival of melanoma patients. This study showed a trend of low expression of Beclin 1 in melanoma; patients with low expression of Beclin 1 were prone to the possibility of distant metastasis. The inconsistent profile of Beclin 1 expression in the prognosis of melanoma patients warrants further clinical investigation.

Beclin1‑armed oncolytic Vaccinia virus enhances the therapeutic efficacy of R‑CHOP against lymphoma in vitro and in vivo

Non-Hodgkin lymphoma (NHL) is a form of lymphoid malignancy, with diffuse large B cell lymphoma (DLBCL) being the most common NHL isoform. Approximately half of patients with DLBCL are successfully cured via first-line Rituximab, Cyclophosphamide, Epirubicin, Vindesine, Prednisolone (R-CHOP) treatment. However, 30–40% of patients with DLBCL ultimately suffer from treatment-refractory or relapsed disease. These patients often suffer from high mortality rates owing to a lack of suitable therapeutic options, and all patients are at a high risk of serious treatment-associated dose-dependent toxicity. As such, it is essential to develop novel treatments for NHL that are less toxic and more efficacious. Oncolytic Vaccinia virus (OVV) has shown promise as a means of treating numerous types of cancer. Gene therapy strategies further enhance OVV-based therapy by improving tumor cell recognition and immune evasion. Beclin1 is an autophagy-associated gene that, when upregulated, induces excess autophagy and cell death. The present study aimed to develop an OVV-Beclin1 therapy capable of inducing autophagic tumor cell death. OVV-Beclin1 was able to efficiently kill NHL cells and to increase the sensitivity of these cells to R-CHOP, thereby decreasing the dose-dependent toxic side effects associated with this chemotherapeutic regimen. The combination of OVV-Beclin1 and R-CHOP also significantly improved tumor growth inhibition and survival in a BALB/c murine model system owing to the synergistic induction of autophagic cell death. Together, these findings suggest that OVV-Beclin1 infection can induce significant autophagic cell death in NHL, highlighting this as a novel means of inducing tumor cell death via a mechanism that is distinct from apoptosis and necrosis.

Single-cell analysis of copy-number alterations in serous ovarian cancer reveals substantial heterogeneity in both low- and high-grade tumors

Unusually high aneuploidy is a hallmark of epithelial serous ovarian cancer (SOC). Previous analyses have focused on aneuploidy on average across all tumor cells. With the expansion of single-cell sequencing technologies, however, an analysis of copy number heterogeneity cell-to-cell is now technically feasible. Here, we describe an analysis of single-cell RNA sequencing (scRNA-seq) data to infer arm-level aneuploidy in individual serous ovarian cancer cells. By first clustering high-quality sequenced epithelial versus non-epithelial cells, high-confidence tumor cell populations were identified. InferCNV was used to predict segmented copy-number alterations (CNAs), which were then used to determine arm-level aneuploidy at the single-cell level. Control comparisons of normal cells to normal cells showed zero arm-level aneuploidy, whereas a median of four aneuploid events were detectable in cancer cells. A heterogeneity analysis of high-grade tumor cells compared to low-grade tumor cells showed similar levels of cell-to-cell variation between cancer grades. Metastatic tumors potentially showed selection pressure with reduced cell-to-cell variation compared to cells from primary tumors. Minor cell populations with CNAs similar to metastatic cells were identified within the matched primary tumors. Taken together, these results provide a minimum estimate for single-cell aneuploidy in serous ovarian cancer and demonstrate the utility of single-cell sequencing for CNA analysis.

BECN1 promotes the migration of NSCLC cells through regulating the ubiquitination of Vimentin

BECN1/Beclin1 is one of the key proteins in autophagy regulation. However, the biological functions of BECN1 in non-small cell lung cancer (NSCLC) were obscure. Here, we found that neither BECN1 knockdown nor overexpression affected the proliferation of NSCLC cells. Surprisingly, BECN1 overexpression increased cell migration and knocking down BECN1 significantly reduced the migratory ability of NSCLC cells. We further demonstrated that BECN1 could interact with Vimentin and affected its K48-linked ubiquitination. What’s more, BECN1 could also interact with ubiquitin-specific peptidase 14 (USP14), the key de-ubiquitinase of Vimentin, and regulated USP14 mediated de-ubiquitination of Vimentin. Thus, our studies revealed an oncosupportive role of BECN1 in the migration of NSCLC cells through regulating the ubiquitination of Vimentin.

The anti-tumourigenic effect of ellagic acid in SKOV-3 ovarian cancer cells entails activation of autophagy mediated by inhibiting Akt and activating AMPK

This study investigated the effect of ellagic acid (EA) on SKOV-3 cell growth and invasiveness and tested if the underlying mechanism involves modulating autophagy. Cells were treated with EA in the presence or absence of chloroquine (CQ), an autophagy inhibitor, compound C (CC), an AMPK inhibitor, or an insulin-like growth factor-1 (IGF-1), a PI3K/Akt activator. EA, at an IC₅₀ of 36.6 µmol/L, inhibited cell proliferation, migration, and invasion and induced cell apoptosis in SKOV-3 cells. These events were prevented by CQ. Also, EA increased levels of Beclin-1, ATG-5, LC3I/II, Bax, cleaved caspase-3/8 and reduced those of p62 and Bcl-2 in these cancer cells. Mechanistically, EA decreased levels of p-S6K1 (Thr³⁸⁹ ) and 4EBP-1 (Thr^37/46 ), two downstream targets of mTORC1, and p-Akt (Thr³⁰⁸ ) but increased levels of AMPK (Thr¹⁷² ) and p-raptor (Ser⁷⁹² ), a natural inhibitor of mTORC1. CC or IGF-1 alone partially prevented the effect of EA on cell survival, cell invasions, and levels of LDH, Beclin-1, and cleaved caspase-3. In conclusion, EA can inhibit SKOV-3 growth, migration, and invasion by activating cytotoxic autophagy mediated by inhibition of mTORC1 and Akt and activation of AMPK.

A novel role for NUAK1 in promoting ovarian cancer metastasis through regulation of fibronectin production in spheroids

Epithelial ovarian cancer (EOC) has a unique mode of metastasis, where cells shed from the primary tumour, form aggregates called spheroids to evade anoikis, spread through the peritoneal cavity, and adhere to secondary sites. We previously showed that the master kinase Liver kinase B1 (LKB1) is required for EOC spheroid viability and metastasis. We have identified novel (nua) kinase 1 (NUAK1) as a top candidate LKB1 substrate in EOC cells and spheroids using a multiplex inhibitor beads-mass spectrometry approach. We confirmed that LKB1 maintains NUAK1 phosphorylation and promotes its stabilization. We next investigated NUAK1 function in EOC cells. Ectopic NUAK1-overexpressing EOC cell lines had increased adhesion, whereas the reverse was seen in OVCAR8-NUAK1KO cells. In fact, cells with NUAK1 loss generate spheroids with reduced integrity, leading to increased cell death after long-term culture. Following transcriptome analysis, we identified reduced enrichment for cell interaction gene expression pathways in OVCAR8-NUAK1KO spheroids. In fact, the FN1 gene, encoding fibronectin, exhibited a 745-fold decreased expression in NUAK1KO spheroids. Fibronectin expression was induced during native spheroid formation, yet this was completely lost in NUAK1KO spheroids. Co-incubation with soluble fibronectin restored the compact spheroid phenotype to OVCAR8-NUAK1KO cells. In a xenograft model of intraperitoneal metastasis, NUAK1 loss extended survival and reduced fibronectin expression in tumours. Thus, we have identified a new mechanism controlling EOC metastasis, through which LKB1-NUAK1 activity promotes spheroid formation and secondary tumours via fibronectin production.

Activated CAMKKβ-AMPK signaling promotes autophagy in a spheroid model of ovarian tumour metastasis

Background

A hallmark of epithelial ovarian cancer (EOC) metastasis is the process of spheroid formation, whereby tumour cells aggregate into 3D structures while in suspension in the peritoneal cavity. EOC spheroids are subjected to bioenergetic stress, thereby activating AMP-activated protein kinase (AMPK) signaling to enter a metabolically quiescent state, which can facilitate cell survival under nutrient-limiting conditions. Independently, we have also demonstrated that EOC spheroids induce autophagy, a process that degrades and recycles intracellular components to restore energy and metabolites. Herein, we sought to examine whether AMPK controls autophagy induction as a cell survival mechanism in EOC spheroids.

Results

We observed a co-ordinate increase in phosphorylated AMPK and the autophagy marker LC3-II during EOC spheroid formation. Reduced AMPK expression by siRNA-mediated knockdown of PRKAA1 and PRKAA2 blocked autophagic flux in EOC spheroids as visualized by fluorescence microscopy using the mCherry-eGFP-LC3B reporter. A complementary approach using pharmacologic agents Compound C and CAMKKβ inhibitor STO-609 to inhibit AMPK activity both yielded a potent blockade of autophagic flux as well. However, direct activation of AMPK in EOC cells using oligomycin and metformin was insufficient to induce autophagy. STO-609 treatment of EOC spheroids resulted in reduced viability in 7 out of 9 cell lines, but with no observed effect in non-malignant FT190 cell spheroids.

Conclusions

Our results support the premise that CAMKKβ-mediated AMPK activity is required, at least in part, to regulate autophagy induction in EOC spheroids and support cell viability in this in vitro model of EOC metastasis.

Inhibiting ULK1 kinase decreases autophagy and cell viability in high-grade serous ovarian cancer spheroids

Metastasis in high-grade serous ovarian cancer (HGSOC) occurs through an unconventional route that involves exfoliation of cancer cells from primary tumors and peritoneal dissemination via multicellular clusters or spheroids. Previously, we demonstrated autophagy induction in HGSOC spheroids grown in vitro and in spheroids collected from ovarian cancer patient ascites; thus, we speculate that autophagy may contribute to spheroid cell survival and overall disease progression. Hence, in this study we sought to evaluate whether ULK1 (unc-51-like kinase-1), a serine-threonine kinase critical for stress-induced autophagy, is important for autophagy regulation in HGSOC spheroids. We demonstrate that HGSOC spheroids have increased ULK1 protein expression that parallels autophagy activation. ULK1 knockdown increased p62 accumulation and decreased LC3-II/I ratio in HGSOC spheroids. In addition, knocking down ATG13, a protein that regulates ULK1 activity via complex formation, phenocopied our ULK1 knockdown results. HGSOC spheroids were blocked in autophagic flux due to ULK1 and ATG13 knockdown as determined by an mCherry-eGFP-LC3B fluorescence reporter. These observations were recapitulated when HGSOC spheroids were treated with an ULK1 kinase inhibitor, MRT68921. Autophagy regulation in normal human fallopian tube epithelial FT190 cells, however, may bypass ULK1, since MRT68921 reduced viability in HGSOC spheroids but not in FT190 cells. Interestingly, ULK1 mRNA expression is negatively correlated with patient survival among stage III and stage IV serous ovarian cancer patients. As we observed using established HGSOC cell lines, cultured spheroids using our new, patient-derived HGSOC cells were also sensitive to ULK1 inhibition and demonstrated reduced cell viability to MRT68921 treatment. These results demonstrate the importance of ULK1 for autophagy induction in HGSOC spheroids and therefore justifies further evaluation of MRT68921, and other novel ULK1 inhibitors, as potential therapeutics against metastatic HGSOC.

Autophagy gene haploinsufficiency drives chromosome instability, increases migration, and promotes early ovarian tumors

Autophagy, particularly with BECN1, has paradoxically been highlighted as tumor promoting in Ras-driven cancers, but potentially tumor suppressing in breast and ovarian cancers. However, studying the specific role of BECN1 at the genetic level is complicated due to its genomic proximity to BRCA1 on both human (chromosome 17) and murine (chromosome 11) genomes. In human breast and ovarian cancers, the monoallelic deletion of these genes is often co-occurring. To investigate the potential tumor suppressor roles of two of the most commonly deleted autophagy genes in ovarian cancer, BECN1 and MAP1LC3B were knocked-down in atypical (BECN1+/+ and MAP1LC3B+/+) ovarian cancer cells. Ultra-performance liquid chromatography mass-spectrometry metabolomics revealed reduced levels of acetyl-CoA which corresponded with elevated levels of glycerophospholipids and sphingolipids. Migration rates of ovarian cancer cells were increased upon autophagy gene knockdown. Genomic instability was increased, resulting in copy-number alteration patterns which mimicked high grade serous ovarian cancer. We further investigated the causal role of Becn1 haploinsufficiency for oncogenesis in a MISIIR SV40 large T antigen driven spontaneous ovarian cancer mouse model. Tumors were evident earlier among the Becn1+/- mice, and this correlated with an increase in copy-number alterations per chromosome in the Becn1+/- tumors. The results support monoallelic loss of BECN1 as permissive for tumor initiation and potentiating for genomic instability in ovarian cancer.

Exendin-4 Induces Cytotoxic Autophagy in Two Ovarian Cancer Cell Lines through Inhibition of Mtorc1 Mediated by Activation of AMPK and Suppression of Akt

Activation of autophagy suppresses ovarian cancer (OC). This in vitro study investigated whether the anti-tumour effect of exendin-4 against OC involves modulation of autophagy and figured out the possible mechanisms of action. SKOV-3 and OVCAR-3 cells (1 × 105/ml) were cultured in DMEM medium and treated with exendin-4 in the presence or absence of chloroquine (CQ), an autophagy inhibitor. In some cases, cells were also treated with exendin- 4 with or without pre-treatment with compound C (CC), an AMPK inhibitor, or insulin-like growth factor (IGF-1), a PI3K/Akt activator. Exendin-4 increased expression of beclin-1 and LC3I/II, suppressed expression of p62, reduced cell survival, migration, and invasion, and increased cell apoptosis and LDH release in both SKOV-3 and OVCAR-3 cells. Besides, exendin-4 reduced phosphorylation of mTORC1, 6SK, 4E-BP1, and Akt but increased phosphorylation of AMPK in both cell lines. These effects were associated with down-regulation of Bcl-2, suppression of nuclear phosphorylation of NF-κB p65, and increased expression of Bax and cleaved caspases 3/8. Chloroquine completely prevented the inhibitory effects of exendin-4 on the cell survival, Bcl-2, NF-κB, and cell invasiveness and abolished its stimulation of cell apoptosis and LDH release. Moreover, only the combined treatment with IGF-1 and CC completely abolished the observed effect of exendin-4 on the expression of beclin-1, LC3I/II, p62, as well as on cell survival, apoptosis, and LDH release. Exendin-4 exhibits a potent anti-tumour cytotoxic effect in SKOV-3 and OVCAR-3 cells by activating the markers of autophagy, mediated by activation of AMPK and inhibition of Akt.

Molecular events in MSC exosome mediated cytoprotection in cardiomyocytes

A host of hormonal-metabolic alterations take place following exposure of cardiomyocytes to hypoxia and other noxious stimuli. Here, we demonstrate that exposure of cultured rat cardiomyocytes to lipopolysaccharide (LPS) resulted in upregulation (~1.5 fold) of oxidized low-density lipoprotein receptor-1 (LOX-1). There was also a marked increase in apoptosis 12 hrs after LPS treatment with caspase-3 levels being significantly elevated (~1.3 fold) and a significant increase in LDH release at 24 hrs. Interestingly, there was a ~1.4-fold upregulation of LC-3 expression post-LPS treatment indicating development of autophagy, which probably is a compensatory response to combat cellular injury induced by LPS. Treatment with LPS also reduced the size and morphology of cardiomyocyte spheroids. In an attempt to limit LPS-induced injury, cardiomyocytes were treated with exosomes derived from mesenchymal stromal cells (MSCs). We noted a significant suppression of LOX-1 expression that in turn suppressed apoptosis as well as autophagic response and restored spheroid morphology. Mass spectrophotometric analysis of MSC exosomes revealed a cargo rich in proteins which are involved in pathways negatively modulating cell death and apoptosis while promoting cell survival. This is first report to our knowledge on the initial molecular events in MSC exosome mediated cytoprotection of stressed cardiomyocytes.

Changes in the Blood-Brain Barrier Function Are Associated With Hippocampal Neuron Death in a Kainic Acid Mouse Model of Epilepsy

The kainic acid (KA)-induced epilepsy experimental model is widely used to study the mechanisms underlying this disorder. Recently, the blood-brain barrier (BBB) has become an innovative alternative treatment target for epilepsy patients. KA causes neuronal injury and BBB damage in this experimental epilepsy model but the mechanisms underlying epilepsy-related neuronal injury, autophagy, and BBB damage remain unclear. Therefore, the present study investigated the relationships among neuronal injury, the expressions of autophagy-related proteins, and changes in BBB-related proteins during the acute phase of epilepsy to further understand the mechanisms and pharmacotherapy of epilepsy. NeuN immunohistochemistry and Fluoro-Jade B (FJ-B) staining in the hippocampal CA3 region revealed that neuronal death induced by intraventricular injections of 10 μg/kg KA was greater than that induced by 3 μg/kg KA. In addition, there were transient increases in the levels of microtubule-associated protein light chain 3-II (LC3I/II) and Beclin-1, which are autophagy-related proteins involved in neuronal death, in this region 24 h after the administration of 10 μg/kg KA. There were also morphological changes in BBB-related cells such as astrocytes, endothelial cells (ECs), and tight junctions (TJs). More specifically, there was a significant increase in the activation of astrocytes 72 h after the administration of 10 μg/kg KA as well as continuous increases in the expressions of platelet endothelial cell adhesion molecule-1 (PECAM-1) and BBB-related TJ proteins (Zonula occludens-1 and Claudin-5) until 72 h after KA treatment. These results suggest that the overexpression of autophagy-related proteins and astrocytes and transient increases in the expressions of BBB-related TJ proteins may be closely related to autophagic neuronal injury. These findings provide a basis for the identification of novel therapeutic targets for patients with epilepsy.

Fluid Shear Stress Promotes Autophagy in Hepatocellular Carcinoma Cells

The autophagy in cancer cells is recognized as an essential hallmark of tumors, which can enhance cancer cell migration and invasion, and result in high incidence of tumor metastasis. The fluid shear stress (FSS) in tumor mechanical microenvironment plays a pivotal role in mediating the behaviors and functions of cells. In this study, the hepatocellular carcinoma cells were exposed to 1.4 dyn/cm² FSS to explore whether FSS could induce autophagy. The results of TEM, Ad-mCherry-GFP labeled LC3B, and mRNA and protein expression of autophagy markers confirmed that FSS could induce autophagy in a time-dependent manner. Additionally, the inhibition of autophagy significantly downregulated the expression of PI3K, FAK and Rho GTPases, and attenuated the ability of cell migration, suggesting that FSS-induced autophagy depended on PI3K- FAK-Rho GTPases pathway. This study elucidated the role of FSS in inducing autophagy during tumor progression, which has emerged as a promising clinical strategy for cancer.

Beclin1 overexpression suppresses tumor cell proliferation and survival via an autophagy‑dependent pathway in human synovial sarcoma cells

Beclin1 is an important autophagy‑related prot-ein, which is involved in both autophagy and apoptosis. In recent years, the antitumor effect of Beclin1 has received increased attention. In the present study, we established a stable Beclin1‑overexpressing cell line with SW982 human synovial sarcoma cells. We found that Beclin1 overexpression decreased the cell viability, inhibited proliferation and induced apoptosis in SW982 cells. The expression levels of Bcl‑2 and PCNA were decreased, while the levels of cleaved‑caspase‑3 and cleaved‑PARP were increased. Beclin1 is closely related with autophagy, thus the autophagy‑related markers LC3 and p62 were detected by western blot analysis, and transmission electron microscopy was used to observe autophagosomes. The results showed that the expression level of LC3II was increased and that of p62 was decreased. Moreover, many double membrane‑enclosed autophagosomes were found in cells with Beclin1 overexpression, which indicated that the autophagic activity was enhanced. To explore the effect of autophagy on the viability of SW982 cells, Atg5 was knocked down using siRNA to inhibit the autophagic activity. We found that autophagy contributed to the decrease in cell viability. Knockdown of Atg5 increased the viability and decreased the apoptotic rate of SW982 cells with Beclin1 overexpression. The expression level of Bcl‑2 was increased, while the expression levels of cleaved‑caspase‑3 and cleaved‑PARP were decreased. We also found that the Akt/Bcl‑2/caspase‑9 pathway was involved. The phosphorylation of AKT was positively correlated with cell viability. The cleavage of caspase‑9 was increased by Beclin1 overexpression and decreased by inhibition of autophagy. Altogether, our results suggested that both autophagy and apoptosis contributed to the antitumor effect of Beclin1 in SW982 cells.

BECN1-knockout impairs tumor growth, migration and invasion by suppressing the cell cycle and partially suppressing the epithelial-mesenchymal transition of human triple-negative breast cancer cells

Beclin1 (BECN1), which directly interacts with B‑cell lymphoma 2, serves an important role in autophagy and is involved in the tumorigenesis of various types of cancer. However, the definite role of BECN1 in breast cancer remains controversial. Bi-allelic knockout of Becn1 in a mouse model leads to an embryonic lethal phenotype, which hampers further investigation. To generate cell lines with knockout of BECN1, the CRISPR/Cas9 technique was used to disrupt BECN1 in human triple-negative breast cancer (TNBC) MDA‑MB‑231 cells. To the best of our knowledge, the present study was the first to successfully disrupt BECN1 in MDA‑MB‑231 cells and to screen three stable monoclonal BECN1‑knockout cell lines, suggesting that BECN1‑knockout is not lethal in TNBC cells. Functional analysis revealed that complete loss of BECN1 suppressed MDA‑MB‑231 proliferation and colony formation via inducing G0/G1 cell cycle arrest, not apoptosis, in vitro. On the other hand, BECN1‑knockout inhibited the migratory and invasive ability of MDA‑MB‑231 cells by partially reversing signals of epithelial-mesenchymal transition. Finally, analysis of publicly available gene expression datasets revealed increased expression of BECN1 in TNBC samples. Taken together, the results of the present study identified BECN1 as an oncogene, providing a novel potential target for the treatment of TNBC.

Prucalopride Inhibits Proliferation of Ovarian Cancer Cells via Phosphatidylinositol 3-Kinase (PI3K) Signaling Pathway

BACKGROUND Ovarian cancer is the second most common malignant tumor of the female reproductive system and is the leading cause of death of gynecological malignancies, but at present there is no effective and safe therapy. There is no previously published report on the anti-cancer effect of prucalopride, which is a high-affinity 5-HT4 receptor. The aim of the present study was to determine whether prucalopride can inhibit proliferation of ovarian cancer cells. MATERIAL AND METHODS The cell viability was detected by use of the Cell Counting Kit-8 (CCK-8) assay. The invasion and migration of SKOV3 and OVCAR3 cells was detected by Transwell assay. The cell apoptosis was detected by apoptosis flow detection and Caspase-Glo 3/7 Assay Systems. The apoptosis-related proteins, autophagy marker proteins, and the related-factors of phosphatidylinositol 3-kinase (PI3K) were detected by Western blot. RESULTS The CCK-8 proliferation test showed that prucalopride inhibited the growth of ovarian cancer cell lines SKOV3 and OVCAR3. In the Transwell assay, prucalopride inhibited cell invasion and migration. Furthermore, we found the expression of anti-apoptotic protein Bcl-2 decreased, whereas the expression of pro-apoptotic protein Caspase3 and Bax increased in the SKOV3 cell line treated with prucalopride, as well as cleaved PARP. In addition, the expression of p-AKT, p-mTOR, and p70S6K decreased in the prucalopride-treated group, and the expression of autophagy marker protein LC3-II/I and Beclin1 significantly increased, whereas the expression of p62 protein decreased. CONCLUSIONS The present study reveals that in ovarian cancer cells, prucalopride inhibits proliferation, migration, and invasion, and induces apoptosis and autophagy, which may be regulated by the PI3K signaling pathway. These results suggest prucalopride has potential as a new drug for clinical ovarian cancer treatment.

Autophagy as an emerging therapy target for ovarian carcinoma

Autophagy is a conserved cellular self-digestion pathway for maintenance of homeostasis under basal and stressed conditions. Autophagy plays pivotal roles in the pathogenesis of many diseases, such as aging-related diseases, autoimmune diseases, cardiovascular diseases, and cancers. Of special note is that accumulating data suggest an intimate relationship between autophagy and ovarian carcinoma. Autophagy is well identified to act as either as a tumor-suppressor or as a tumor-promoter in ovarian carcinoma. The exact function of autophagy in ovarian carcinoma is highly dependent on the circumstances of cancer including hypoxic, nutrient-deficient, chemotherapy and so on. However, the mechanism underlying autophagy associated with ovarian carcinoma remains elusive, the precise role of autophagy in ovarian carcinoma also remains undetermined. In this review, we tried to sum up and discuss recent research achievements of autophagy in ovarian cancer. Moreover, waves of novel therapies ways for ovarian carcinoma based on the functions of autophagy were collected.

Contribution of Hippocampal 5-HT3 Receptors in Hippocampal Autophagy and Extinction of Conditioned Fear Responses after a Single Prolonged Stress Exposure in Rats

One of the hypotheses about the pathogenesis of posttraumatic stress disorder (PTSD) is the dysfunction of serotonin (5-HT) neurotransmission. While certain 5-HT receptor subtypes are likely critical for the symptoms of PTSD, few studies have examined the role of 5-HT3 receptor in the development of PTSD, even though 5-HT3 receptor is critical for contextual fear extinction and anxiety-like behavior. Therefore, we hypothesized that stimulation of 5-HT3 receptor in the dorsal hippocampus (DH) could prevent hippocampal autophagy and the development of PTSD-like behavior in animals. To this end, we infused SR57227, selective 5-HT3 agonist, into the DH after a single prolonged stress (SPS) treatment in rats. Three weeks later, we evaluated the effects of this pharmacological treatment on anxiety-related behaviors and extinction of contextual fear memory. We also accessed hippocampal autophagy and the expression of 5-HT3A subunit, Beclin-1, LC3-I, and LC3-II in the DH. We found that SPS treatment did not alter anxiety-related behaviors but prolonged the extinction of contextual fear memory, and such a behavioral phenomenon was correlated with increased hippocampal autophagy, decreased 5-HT3A expression, and increased expression of Beclin-1 and LC3-II/LC3-I ratio in the DH. Furthermore, intraDH infusions of SR57227 dose-dependently promoted the extinction of contextual fear memory, prevented hippocampal autophagy, and decreased expression of Beclin-1 and LC3-II/LC3-I ratio in the DH. These results indicated that 5-HT3 receptor in the hippocampus may play a critical role in the pathogenesis of hippocampal autophagy, and is likely involved in the pathophysiology of PTSD.

Modeling the Dynamics of High-Grade Serous Ovarian Cancer Progression for Transvaginal Ultrasound-Based Screening and Early Detection

High-grade serous ovarian cancer (HGSOC) represents the majority of ovarian cancers and accounts for the largest proportion of deaths from the disease. A timely detection of low volume HGSOC should be the goal of any screening studies. However, numerous transvaginal ultrasound (TVU) detection-based population studies aimed at detecting low-volume disease have not yielded reduced mortality rates. A quantitative invalidation of TVU as an effective HGSOC screening strategy is a necessary next step. Herein, we propose a mathematical model for a quantitative explanation on the reported failure of TVU-based screening to improve HGSOC low-volume detectability and overall survival.We develop a novel in silico mathematical assessment of the efficacy of a unimodal TVU monitoring regimen as a strategy aimed at detecting low-volume HGSOC in cancer-positive cases, defined as cases for which the inception of the first malignant cell has already occurred. Our findings show that the median window of opportunity interval length for TVU monitoring and HGSOC detection is approximately 1.76 years. This does not translate into reduced mortality levels or improved detection accuracy in an in silico cohort across multiple TVU monitoring frequencies or detection sensitivities. We demonstrate that even a semiannual, unimodal TVU monitoring protocol is expected to miss detectable HGSOC. Lastly, we find that circa 50% of the simulated HGSOC growth curves never reach the baseline detectability threshold, and that on average, 5-7 infrequent, rate-limiting stochastic changes in the growth parameters are associated with reaching HGSOC detectability and mortality thresholds respectively. Focusing on a malignancy poorly studied in the mathematical oncology community, our model captures the dynamic, temporal evolution of HGSOC progression. Our mathematical model is consistent with recent case reports and prospective TVU screening population studies, and provides support to the empirical recommendation against frequent HGSOC screening.