Autophagy induction impairs migration and invasion by reversing EMT in glioblastoma cells

Autophagy in glioblastoma: A mechanistic perspective

Glioblastoma (GBM) is one of the most lethal malignancies in humans. Even after surgical resection and aggressive radio- or chemotherapies, patients with GBM can survive for less than 14 months. Extreme inter-tumor and intra-tumor heterogeneity of GBM poses a challenge for resolving recalcitrant GBM pathophysiology. GBM tumor microenvironment (TME) exhibits diverse heterogeneity in cellular composition and processes contributing to tumor progression and therapeutic resistance. Autophagy is such a cellular process; that demonstrates a cell-specific and TME context-dependent role in GBM progression, leading to either the promotion or suppression of GBM progression. Autophagy can regulate GBM cell function directly via regulation of survival, migration, and invasion, or indirectly by affecting GBM TME composition such as immune cell population, tumor metabolism, and glioma stem cells. This review comprehensively investigates the role of autophagy in GBM pathophysiology.

Dual perspective on autophagy in glioma: Detangling the dichotomous mechanisms of signaling pathways for therapeutic insights

Autophagy is a normal physiological process that aids the recycling of cellular nutrients, assisting the cells to cope with stressed conditions. However, autophagy's effect on cancer, including glioma, is uncertain and involves complicated molecular mechanisms. Several contradictory reports indicate that autophagy may promote or suppress glioma growth and progression. Autophagy inhibitors potentiate the efficacy of chemotherapy or radiation therapy in glioma. Numerous compounds stimulate autophagy to cause glioma cell death. Autophagy is also involved in the therapeutic resistance of glioma. This review article aims to detangle the complicated molecular mechanism of autophagy to provide a better perception of the two-sided role of autophagy in glioma and its therapeutic implications. The protein and epigenetic modulators of the cytoprotective and cytotoxic role of autophagy are described in this article. Moreover, several signaling pathways are associated with autophagy and its effects on glioma. We have reviewed the molecular pathways and highlighted the signaling axis involved in cytoprotective and cytotoxic autophagy. Additionally, this article discusses the role of autophagy in therapeutic resistance, including glioma stem cell maintenance and tumor microenvironment regulation. It also summarizes several investigations on the anti-glioma effects of autophagy modulators to understand the associated mechanisms and provide insights regarding its therapeutic implications.

SIRT1 silencing promotes EMT and Crizotinib resistance by regulating autophagy through AMPK/mTOR/S6K signaling pathway in EML4-ALK L1196M and EML4-ALK G1202R mutant non-small cell lung cancer cells

Most EML4-ALK rearrangement non-small cell lung cancer (NSCLC) patients inevitably develop acquired drug resistance after treatment. The main mechanism of drug resistance is the acquired secondary mutation of ALK kinase domain. L1196M and G1202R are classical mutation sites. We urgently need to understand the underlying molecular mechanism of drug resistance to study the therapeutic targets of mutant drug-resistant NSCLC cells. The silent information regulator sirtuin1 (SIRT1) can regulate the normal energy metabolism of cells, but its role in cancer is still unclear. In our report, it was found that the SIRT1 in EML4-ALK G1202R and EML4-ALK L1196M mutant drug-resistant cells was downregulated compared with EML4-ALK NSCLC cells. The high expression of SIRT1 was related to the longer survival time of patients with lung cancer. Activation of SIRT1 induced autophagy and suppressed the invasion and migration of mutant cells. Further experiments indicated that the activation of SIRT1 inhibited the phosphorylation level of mTOR and S6K by upregulating the expression of AMPK, thus activating autophagy. SIRT1 can significantly enhanced the sensitivity of mutant cells to crizotinib, improved its ability to promote apoptosis of mutant cells, and inhibited cell proliferation. In conclusion, SIRT1 is a key regulator of drug resistant in EML4-ALK L1196M and G1202R mutant cells. SIRT1 may be a novel therapeutic target for EML4-ALK drug resistant NSCLC.

Role of Tumor Cell Intrinsic and Host Autophagy in Cancer

Macroautophagy (autophagy hereafter) is an intracellular nutrient scavenging pathway induced by starvation and other stressors whereby cellular components such as organelles are captured in double-membrane vesicles (autophagosomes), whereupon their contents are degraded through fusion with lysosomes. Two main purposes of autophagy are to recycle the intracellular breakdown products to sustain metabolism and survival during starvation and to eliminate damaged or excess cellular components to suppress inflammation and maintain homeostasis. In contrast to most normal cells and tissues in the fed state, tumor cells up-regulate autophagy to promote their growth, survival, and malignancy. This tumor-cell-autonomous autophagy supports elevated metabolic demand and suppresses tumoricidal activation of the innate and adaptive immune responses. Tumor-cell-nonautonomous (e.g., host) autophagy also supports tumor growth by maintaining essential tumor nutrients in the circulation and tumor microenvironment and by suppressing an antitumor immune response. In the setting of cancer therapy, autophagy is a resistance mechanism to chemotherapy, targeted therapy, and immunotherapy. Thus, tumor and host autophagy are protumorigenic and autophagy inhibition is being examined as a novel therapeutic approach to treat cancer.

Dissecting the multifaceted roles of autophagy in cancer initiation, growth, and metastasis: from molecular mechanisms to therapeutic applications

Autophagy is a cytoplasmic defense mechanism that cells use to break and reprocess their intracellular components. This utilization of autophagy is regarded as a savior in nutrient-deficient and other stressful conditions. Hence, autophagy keeps contact with and responds to miscellaneous cellular tensions and diverse pathways of signal transductions, such as growth signaling and cellular death. Importantly, autophagy is regarded as an effective tumor suppressor because regular autophagic breakdown is essential for cellular maintenance and minimizing cellular damage. However, paradoxically, autophagy has also been observed to promote the events of malignancies. This review discussed the dual role of autophagy in cancer, emphasizing its influence on tumor survival and progression. Possessing such a dual contribution to the malignant establishment, the prevention of autophagy can potentially advocate for the advancement of malignant transformation. In contrast, for the context of the instituted tumor, the agents of preventing autophagy potently inhibit the advancement of the tumor. Key regulators, including calpain 1, mTORC1, and AMPK, modulate autophagy in response to nutritional conditions and stress. Oncogenic mutations like RAS and B-RAF underscore autophagy's pivotal role in cancer development. The review also delves into autophagy's context-dependent roles in tumorigenesis, metastasis, and the tumor microenvironment (TME). It also discusses the therapeutic effectiveness of autophagy for several cancers. The recent implication of autophagy in the control of both innate and antibody-mediated immune systems made it a center of attention to evaluating its role concerning tumor antigens and treatments of cancer.

STAT3 phosphorylation inhibitor Bt354 exhibits anti-neoplastic activity in glioblastoma multiforme cells

The high mortality rate of glioblastoma multiforme (GBM), a lethal primary brain tumor, is attributable to postsurgical recurrence. STAT3, an oncogenic protein, is a signal transducer and transcription activator encourages cancer cell migration and proliferation, which results in resistance to therapy. STAT3 inhibition reduces cancer metastasis and improves patient prognosis. Bt354, a small molecule STAT inhibitor, exhibits significant cytotoxic and anti-proliferative activities against certain cancer types. Here, we demonstrated that exposure of GBM cells (U87 MG) to Bt354 had a significant, concentration-dependent growth suppression. Bt354 also induced apoptosis and downregulated the expression of the epithelial-mesenchymal transition genes. Therefore, this study suggests the potential of Bt354 for treating GBM owing to its ability to induce cytotoxicity.

TRAIL and Celastrol Combinational Treatment Suppresses Proliferation, Migration, and Invasion of Human Glioblastoma Cells via Targeting Wnt/β-catenin Signaling Pathway

OBJECTIVE

To investigate the mechanistic basis for the anti-proliferation and anti-invasion effect of tumor necrosis factor-related apoptosis-induced ligand (TRAIL) and celastrol combination treatment (TCCT) in glioblastoma cells.

METHODS

Cell counting kit-8 was used to detect the effects of different concentrations of celastrol (0-16 µmol/L) and TRAIL (0-500 ng/mL) on the cell viability of glioblastoma cells. U87 cells were randomly divided into 4 groups, namely control, TRAIL (TRAIL 100 ng/mL), Cel (celastrol 0.5 µmol/L) and TCCT (TRAIL 100 ng/mL+ celastrol 0.5 µmol/L). Cell proliferation, migration, and invasion were detected by colony formation, wound healing, and Transwell assays, respectively. Quantitative reverse transcription polymerase chain reaction and Western blotting were performed to assess the levels of epithelial-mesenchymal transition (EMT) markers (zona occludens, N-cadherin, vimentin, zinc finger E-box-binding homeobox, Slug, and β-catenin). Wnt pathway was activated by lithium chloride (LiCl, 20 mol/L) and the mechanism for action of TCCT was explored.

RESULTS

Celastrol and TRAIL synergistically inhibited the proliferation, migration, invasion, and EMT of U87 cells (P<0.01). TCCT up-regulated the expression of GSK-3β and down-regulated the expression of β-catenin and its associated proteins (P<0.05 or P<0.01), including c-Myc, Cyclin-D1, and matrix metalloproteinase (MMP)-2. In addition, LiCl, an activator of the Wnt signaling pathway, restored the inhibitory effects of TCCT on the expression of β-catenin and its downstream genes, as well as the migration and invasion of glioblastoma cells (P<0.05 or P<0.01).

CONCLUSIONS

Celastrol and TRAIL can synergistically suppress glioblastoma cell migration, invasion, and EMT, potentially through inhibition of Wnt/β-catenin pathway. This underlies a novel mechanism of action for TCCT as an effective therapy for glioblastoma.

Immune checkpoints between epithelial-mesenchymal transition and autophagy: A conflicting triangle

Inhibitory immune checkpoint (ICP) molecules are pivotal in inhibiting innate and acquired antitumor immune responses, a mechanism frequently exploited by cancer cells to evade host immunity. These evasion strategies contribute to the complexity of cancer progression and therapeutic resistance. For this reason, ICP molecules have become targets for antitumor drugs, particularly monoclonal antibodies, collectively referred to as immune checkpoint inhibitors (ICI), that counteract such cancer-associated immune suppression and restore antitumor immune responses. Over the last decade, however, it has become clear that tumor cell-associated ICPs can also induce tumor cell-intrinsic effects, in particular epithelial-mesenchymal transition (EMT) and macroautophagy (hereafter autophagy). Both of these processes have profound implications for cancer metastasis and drug responsiveness. This article reviews the positive or negative cross-talk that tumor cell-associated ICPs undergo with autophagy and EMT. We discuss that tumor cell-associated ICPs are upregulated in response to the same stimuli that induce EMT. Moreover, ICPs themselves, when overexpressed, become an EMT-inducing stimulus. As regards the cross-talk with autophagy, ICPs have been shown to either stimulate or inhibit autophagy, while autophagy itself can either up- or downregulate the expression of ICPs. This dynamic equilibrium also extends to the autophagy-apoptosis axis, further emphasizing the complexities of cellular responses. Eventually, we delve into the intricate balance between autophagy and apoptosis, elucidating its role in the broader interplay of cellular dynamics influenced by ICPs. In the final part of this article, we speculate about the driving forces underlying the contradictory outcomes of the reciprocal, inhibitory, or stimulatory effects between ICPs, EMT, and autophagy. A conclusive identification of these driving forces may allow to achieve improved antitumor effects when using combinations of ICIs and compounds acting on EMT and/or autophagy. Prospectively, this may translate into increased and/or broadened therapeutic efficacy compared to what is currently achieved with ICI-based clinical protocols.

Lysosomes in Cancer-At the Crossroad of Good and Evil

Although it has been known for decades that lysosomes are central for degradation and recycling in the cell, their pivotal role as nutrient sensing signaling hubs has recently become of central interest. Since lysosomes are highly dynamic and in constant change regarding content and intracellular position, fusion/fission events allow communication between organelles in the cell, as well as cell-to-cell communication via exocytosis of lysosomal content and release of extracellular vesicles. Lysosomes also mediate different forms of regulated cell death by permeabilization of the lysosomal membrane and release of their content to the cytosol. In cancer cells, lysosomal biogenesis and autophagy are increased to support the increased metabolism and allow growth even under nutrient- and oxygen-poor conditions. Tumor cells also induce exocytosis of lysosomal content to the extracellular space to promote invasion and metastasis. However, due to the enhanced lysosomal function, cancer cells are often more susceptible to lysosomal membrane permeabilization, providing an alternative strategy to induce cell death. This review summarizes the current knowledge of cancer-associated alterations in lysosomal structure and function and illustrates how lysosomal exocytosis and release of extracellular vesicles affect disease progression. We focus on functional differences depending on lysosomal localization and the regulation of intracellular transport, and lastly provide insight how new therapeutic strategies can exploit the power of the lysosome and improve cancer treatment.

Metastatic outgrowth via the two-way interplay of autophagy and metabolism

Metastasis represents one of the most dangerous issue of cancer progression, characterized by intricate interactions between invading tumor cells, various proteins, and other cells on the way towards target sites. Tumor cells, while undergoing metastasis, engage in dynamic dialogues with stromal cells and undertake epithelial-mesenchymal transition (EMT) phenoconversion. To ensure survival, tumor cells employ several strategies such as restructuring their metabolic needs to adapt to the alterations of the microenvironmental resources via different mechanisms including macroautophagy (autophagy) and to circumvent anoikis-a form of cell death induced upon detachment from the extracellular matrix (ECM). This review focuses on the puzzling connections of autophagy and energetic metabolism within the context of cancer metastasis.

Autophagy: a necessary evil in cancer and inflammation

Autophagy, a highly regulated cellular process, assumes a dual role in the context of cancer. On the one hand, it functions as a crucial homeostatic pathway, responsible for degrading malfunctioning molecules and organelles, thereby maintaining cellular health. On the other hand, its involvement in cancer development and regression is multifaceted, contingent upon a myriad of factors. This review meticulously examines the intricacies of autophagy, from its molecular machinery orchestrated by Autophagy-Related Genes (ATG) initially discovered in yeast to the various modes of autophagy operative within cells. Beyond its foundational role in cellular maintenance, autophagy reveals context-specific functions in processes like angiogenesis and inflammation. Our analysis delves into how autophagy-related factors directly impact inflammation, underscoring their profound implications for cancer dynamics. Additionally, we extend our inquiry to explore autophagy's associations with cardiovascular conditions, neurodegenerative disorders, and autoimmune diseases, illuminating the broader medical relevance of this process. Furthermore, this review elucidates how autophagy contributes to sustaining hallmark cancer features, including stem cell maintenance, proliferation, angiogenesis, metastasis, and metabolic reprogramming. Autophagy emerges as a pivotal process that necessitates careful consideration in cancer treatment strategies. To this end, we investigate innovative approaches, ranging from enzyme-based therapies to MTOR inhibitors, lysosomal blockers, and nanoparticle-enabled interventions, all aimed at optimizing cancer treatment outcomes by targeting autophagy pathways. In summary, this comprehensive review provides a nuanced perspective on the intricate and context-dependent role of autophagy in cancer biology. Our exploration not only deepens our understanding of this fundamental process but also highlights its potential as a therapeutic target. By unraveling the complex interplay between autophagy and cancer, we pave the way for more precise and effective cancer treatments, promising better outcomes for patients.

Contribution of Autophagy to Epithelial Mesenchymal Transition Induction during Cancer Progression

Epithelial Mesenchymal Transition (EMT) is a dedifferentiation process implicated in many physio-pathological conditions including tumor transformation. EMT is regulated by several extracellular mediators and under certain conditions it can be reversible. Autophagy is a conserved catabolic process in which intracellular components such as protein/DNA aggregates and abnormal organelles are degraded in specific lysosomes. In cancer, autophagy plays a controversial role, acting in different conditions as both a tumor suppressor and a tumor-promoting mechanism. Experimental evidence shows that deep interrelations exist between EMT and autophagy-related pathways. Although this interplay has already been analyzed in previous studies, understanding mechanisms and the translational implications of autophagy/EMT need further study. The role of autophagy in EMT is not limited to morphological changes, but activation of autophagy could be important to DNA repair/damage system, cell adhesion molecules, and cell proliferation and differentiation processes. Based on this, both autophagy and EMT and related pathways are now considered as targets for cancer therapy. In this review article, the contribution of autophagy to EMT and progression of cancer is discussed. This article also describes the multiple connections between EMT and autophagy and their implication in cancer treatment.

PAK inhibitor FRAX486 decreases the metastatic potential of triple-negative breast cancer cells by blocking autophagy

BACKGROUND

Triple-negative breast cancer (TNBC) is a unique breast cancer subtype with a high risk of metastasis and recurrence and a poor prognosis. Epithelial-mesenchymal transition (EMT) endows epithelial cells with the ability to move to distant sites, which is essential for the metastasis of TNBC to organs, including the lung. Autophagy, an intracellular degradation process that involves formation of double-layered lipid autophagosomes that transport cytosolic cargoes into lysosomes via autophagosome-lysosome fusion, is involved in various diseases, including cancer and neurodegenerative, metabolic, cardiovascular, and infectious diseases. The relationship between autophagy and cancer has become relatively clear. However, research on pharmacological drugs that block cancer EMT by targeting autophagy is still in the initial stages. Therefore, the re-evaluation of old drugs for their potential in blocking both autophagy and EMT was conducted.

METHODS

More than 2000 small molecule chemicals were screened for dual autophagy/EMT inhibitors, and FRAX486 was identified as the best candidate inhibitor of autophagy/EMT. The functions of FRAX486 in TNBC metastasis were detected by CCK-8, migration and wound healing assays. The effects of FRAX486 on autophagy and its target PAK2 were determined by immunoblotting, immunofluorescence, immunoprecipitation analysis and transmission electron microscopy. The findings were validated in mouse models.

RESULTS

Here, we report that FRAX486, a potent P21-activated kinase 2 (PAK2) inhibitor, facilitates TNBC suppression both in vitro and in vivo by blocking autophagy. Mechanistically, FRAX486 inhibits autophagy in TNBC cells by targeting PAK2, leading to the ubiquitination and proteasomal degradation of STX17, which mediates autophagosome-lysosome fusion. The inhibition of autophagy by FRAX486 causes upregulation of the epithelial marker protein E-cadherin and thus suppresses the migration and metastasis of TNBC cells.

CONCLUSIONS

The effects of FRAX486 on TNBC metastasis suppression were verified to be dependent on PAK2 and autophagy inhibition. Together, our results provide a molecular basis for the application of FRAX486 as a potential treatment for inhibiting the metastasis of TNBC.

Autophagy machinery in glioblastoma: The prospect of cell death crosstalk and drug resistance with bioinformatics analysis

Brain tumors are common malignancies with high mortality and morbidity in which glioblastoma (GB) is a grade IV astrocytoma with heterogeneous nature. The conventional therapeutics for the GB mainly include surgery and chemotherapy, however their efficacy has been compromised due to the aggressiveness of tumor cells. The dysregulation of cell death mechanisms, especially autophagy has been reported as a factor causing difficulties in cancer therapy. As a mechanism contributing to cell homeostasis, the autophagy process is hijacked by tumor cells for the purpose of aggravating cancer progression and drug resistance. The autophagy function is context-dependent and its role can be lethal or protective in cancer. The aim of the current paper is to highlight the role of autophagy in the regulation of GB progression. The cytotoxic function of autophagy can promote apoptosis and ferroptosis in GB cells and vice versa. Autophagy dysregulation can cause drug resistance and radioresistance in GB. Moreover, stemness can be regulated by autophagy and overall growth as well as metastasis are affected by autophagy. The various interventions including administration of synthetic/natural products and nanoplatforms can target autophagy. Therefore, autophagy can act as a promising target in GB therapy.

A potential therapeutic approach for gastric cancer: inhibition of LACTB transcript 1

BACKGROUND

This study sought to investigate the role of LACTB transcript 1 in regulating adaptive immune resistance and stemness in gastric cancer and its potential as a therapeutic target for precision medicine.

METHODS

Bioinformatics analysis and RT-qPCR were used to analyze the expression level of LACTB and its transcripts in gastric cancer cells. The effects of LACTB transcript 1 on adaptive immune resistance and stemness were evaluated using in vitro cell experiments and western blotting experiments.

RESULTS

Our study findings revealed that LACTB transcript 1 modulated adaptive immune resistance and inhibited the stemness of gastric cancer cells. Knocking down the expression level of LACTB transcript 1 activated autophagy and inhibited EMT. As expected, overexpression of LACTB transcript 1 yielded the opposite findings. The expression level of LACTB transcript 1 in the peripheral blood of gastric cancer patients was consistent with the bioinformatics analysis, suggesting its potential as a biomarker of gastric cancer.

CONCLUSIONS

LACTB transcript 1 is a promising therapeutic target for precision medicine in gastric cancer by modulating immune evasion mechanisms and stemness. These findings provide insights into leveraging long non-coding RNAs (lncRNAs) in immunotherapy, radiotherapy, and chemotherapy to enhance cancer therapy efficacy, particularly in the context of targeting tumor heterogeneity and stemness.

Autophagy Modulation and Its Implications on Glioblastoma Treatment

Autophagy is a vital cellular process that functions to degrade and recycle damaged organelles into basic metabolites. This allows a cell to adapt to a diverse range of challenging conditions. Autophagy assists in maintaining homeostasis, and it is tightly regulated by the cell. The disruption of autophagy has been associated with many diseases, such as neurodegenerative disorders and cancer. This review will center its discussion on providing an in-depth analysis of the current molecular understanding of autophagy and its relevance to brain tumors. We will delve into the current literature regarding the role of autophagy in glioma pathogenesis by exploring the major pathways of JAK2/STAT3 and PI3K/AKT/mTOR and summarizing the current therapeutic interventions and strategies for glioma treatment. These treatments will be evaluated on their potential for autophagy induction and the challenges associated with their utilization. By understanding the mechanism of autophagy, clinical applications for future therapeutics in treating gliomas can be better targeted.

Systems Biology and Cytokines Potential Role in Lung Cancer Immunotherapy Targeting Autophagic Axis

Lung cancer accounts for the highest number of deaths among men and women worldwide. Although extensive therapies, either alone or in conjunction with some specific drugs, continue to be the principal regimen for evolving lung cancer, significant improvements are still needed to understand the inherent biology behind progressive inflammation and its detection. Unfortunately, despite every advancement in its treatment, lung cancer patients display different growth mechanisms and continue to die at significant rates. Autophagy, which is a physiological defense mechanism, serves to meet the energy demands of nutrient-deprived cancer cells and sustain the tumor cells under stressed conditions. In contrast, autophagy is believed to play a dual role during different stages of tumorigenesis. During early stages, it acts as a tumor suppressor, degrading oncogenic proteins; however, during later stages, autophagy supports tumor cell survival by minimizing stress in the tumor microenvironment. The pivotal role of the IL6-IL17-IL23 signaling axis has been observed to trigger autophagic events in lung cancer patients. Since the obvious roles of autophagy are a result of different immune signaling cascades, systems biology can be an effective tool to understand these interconnections and enhance cancer treatment and immunotherapy. In this review, we focus on how systems biology can be exploited to target autophagic processes that resolve inflammatory responses and contribute to better treatment in carcinogenesis.

Fatty acid oxidation supports melanoma cell migration through autophagy regulation

Metastasis is one of the most malignant characteristics of cancer cells, in which metabolic reprogramming is crucial for promoting and sustaining multi-steps of metastasis, including invasion, migration and infiltration. Recently, it has been shown that melanoma cells undergo a metabolic switching toward the upregulation of fatty acid oxidation (FAO) during metastasis. However, the underlying mechanisms by which FAO contributes to metastasis of melanoma cells remain obscure. Here, we report that FAO contributes to melanoma cell migration and invasion by regulating the formation of autophagosomes. Pharmacological or genetic inhibition of FAO impairs migration of melanoma cells, which seems not to be linked to energy production or redox homeostasis. Importantly, we reveal that acetyl-CoA production by FAO contributes to melanoma cell migration through autophagy regulation. Mechanistically, FAO inhibition results in increased autophagosome formation, which suppresses migration and invasion properties of melanoma cells. Our results underscore the crucial role of FAO in melanoma cell migration and support the potential therapeutic relevance of modulating cellular acetyl-CoA levels to inhibit cancer metastasis.

Ferroptosis, autophagy, tumor and immunity

Ferroptosis was first proposed in 2012, a new form of cell death. Autophagy plays a crucial role in cell clearance and maintaining homeostasis. Autophagy is involved in the initial step of ferroptosis under the action of histone elements such as NCOA4, RAB7A, and BECN1. Ferroptosis and autophagy are involved in tumor progression, treatment, and drug resistance in the tumor microenvironment. In this review, we described the mechanisms of ferroptosis, autophagy, and tumor and immunotherapy, respectively, and emphasized the relationship between autophagy-related ferroptosis and tumor.

RAB14 promotes epithelial-mesenchymal transition in bladder cancer through autophagy‑dependent AKT signaling pathway

Bladder cancer (BLCA) is the 9th most common cancer of mortality. Autophagy and epithelial to mesenchymal transition (EMT) have an essential role in cancer invasion and metastasis. However, the relationship between autophagy and EMT is still poorly understood in BLCA. Functional enrichment and pathway network analysis were carried out. Comprehensive protein-protein interactions (PPI) networks were proposed to prioritize candidate autophagy-related genes. Furthermore, an autophagy-related signature and a nomogram model were established by integrating clinical information and this signature risk score to evaluate candidate autophagy-related genes. RAB14 expression and its association with pathological information and survival were evaluated in samples from TCGA dataset. Knocking down RAB14 in T24 cells was constructed, and immunofluorescence staining, transmission electron microscopy, immunohistochemistry and western blotting and a series of functional assays were performed to evaluate the migration, invasion, EMT and autophagy abilities of BLCA cells. The autophagy-related gene RAB14 was the only candidate gene identified by three kinds of analytic approaches. RAB14 was highly upregulated in BLCA and correlated with clinical outcomes based on TCGA BLCA datasets. Knocking down RAB14 was found to inhibit EMT and autophagy in T24 cells. RAB14 levels were positively related to those of LC3B and Beclin1, two genes with critical roles in the autophagy process, and the correlation was further confirmed in clinical tissue specimens by IHC and western blot analysis. In addition, RAB14-promoted EMT, migration, and invasion in T24 cells could be partially reversed by autophagy activator, rapamycin. The effects of RAB14 on autophagy was associated with level of p-Akt, indicating that they were possibly mediated via PI3K/AKT signaling. These findings indicated that autophagy-related gene RAB14-promoted EMT, migration and invasion of bladder cancer via the Akt-associated autophagic pathway.

Adult IDH Wild-Type Glioblastoma Ultrastructural Investigation Suggests a Possible Correlation between Morphological Biomarkers and Ki-67 Index

Glioblastoma is an aggressive brain tumor with an average life expectancy between 14 and 16 months after diagnosis. The Ki-67 labeling index (LI), a measure of cellular proliferation, is emerging as a prognostic marker in GBM. In this study, we investigated the ultrastructure of glioblastoma tissue from 9 patients with the same molecular profile (adult IDH wild-type glioblastoma, wild-type ATRX, and positive for TP53 expression, GFAP expression, and EGFR overexpression) to find possible ultrastructural features to be used as biomarkers and correlated with the only parameter that differs among our samples, the Ki-67 LI. Our main results were the visualization of the anatomical basis of astrocyte-endothelial cells crosstalk; the ultrastructural in situ imaging of clusters of hyperactivated microglia cells (MsEVs); the ultrastructural in situ imaging of microglia cells storing lipid vesicles (MsLVs); the ultrastructural in situ imaging of neoplastic cells mitophagy (NCsM). The statistical analysis of our data indicated that MsEVs and MsLVs correlate with the Ki-67 LI value. We can thus assume they are good candidates to be considered morphological biomarkers correlating to Ki-67 LI. The role of NCsM instead must be further evaluated. Our study findings demonstrate that by combining ultrastructural characteristics with molecular information, we can discover biomarkers that have the potential to enhance diagnostic precision, aid in treatment decision-making, identify targets for therapy, and enable personalized treatment plans tailored to each patient. However, further research with larger sample sizes is needed to validate these findings and fully utilize the potential of ultrastructural analysis in managing glioblastoma.

Inhibition of autophagy; an opportunity for the treatment of cancer resistance

The process of macroautophagy plays a pivotal role in the degradation of long-lived, superfluous, and damaged proteins and organelles, which are later recycled for cellular use. Normal cells rely on autophagy to combat various stressors and insults to ensure survival. However, autophagy is often upregulated in cancer cells, promoting a more aggressive phenotype that allows mutated cells to evade death after exposure to therapeutic treatments. As a result, autophagy has emerged as a significant factor in therapeutic resistance across many cancer types, with underlying mechanisms such as DNA damage, cell cycle arrest, and immune evasion. This review provides a comprehensive summary of the role of autophagy in therapeutic resistance and the limitations of available autophagic inhibitors in cancer treatment. It also highlights the urgent need to explore new inhibitors that can synergize with existing therapies to achieve better patient treatment outcomes. Advancing research in this field is crucial for developing more effective treatments that can help improve the lives of cancer patients.

Impact of context-dependent autophagy states on tumor progression

Macroautophagy is a cellular quality-control process that degrades proteins, protein aggregates and damaged organelles. Autophagy plays a fundamental role in cancer where, in the presence of stressors (for example, nutrient starvation, hypoxia, mechanical pressure), tumor cells activate it to degrade intracellular substrates and provide energy. Cell-autonomous autophagy in tumor cells and cell-nonautonomous autophagy in the tumor microenvironment and in the host converge on mechanisms that modulate metabolic fitness, DNA integrity and immune escape and, consequently, support tumor growth. In this Review, we will discuss insights into the tumor-modulating roles of autophagy in different contexts and reflect on how future studies using physiological culture systems may help to understand the complexity and open new therapeutic avenues.

Delineating the twin role of autophagy in lung cancer

Autophagy represents an intracellular defense mechanism equipped within each eukaryotic cells to enable them to cope with variety of physical, chemical, and biological stresses. This mechanism helps to restore the homeostasis and preserve the cellular integrity and function of the cells. In these conditions, such as hypoxia, nutrient deprivation, inhibition of protein synthesis or microbial attack, the process of autophagy is upregulated to maintain cellular homeostasis. The role of autophagy in cancer is an intriguing topic which needs further exploration. This process of autophagy has been many times referred as a double-edged sword in the process of tumorigenesis. In the initial stages, it may act as a tumor suppressor and enable to quench the damaged organelles and harmful molecules generated. In more advanced stages, autophagy has been shown to act as a tumor-promoting system as it may help the cancer cells to cope better with stressful microenvironments. Besides this, autophagy has been associated with development of resistance to anticancer drugs as well as promoting the immune evasion in cancer cells, representing a serious obstacle in cancer treatment and its outcome. Also, autophagy is associated with hallmarks of cancer that may lead to activation of invasion and metastasis. The information on this twin role needs further exploration and deeper understanding of the pathways involved. In this review, we discuss the various aspects of autophagy during tumor development, from early to late stages of tumor growth. Both the protective role of autophagy in preventing tumor growth and the underlying mechanisms adopted with evidence from past studies have been detailed. Further, the role of autophagy in conferring resistance to distinct lung cancer treatment and immune shielding properties has also been discussed. This is essential for further improving on treatment outcome and success rates.

The STAT3-Regulated Autophagy Pathway in Glioblastoma

Glioblastoma (GBM) is the most common primary brain malignancy in adults with a dismal prognosis. Despite advances in genomic analysis and surgical technique and the development of targeted therapeutics, most treatment options are ineffective and mainly palliative. Autophagy is a form of cellular self-digestion with the goal of recycling intracellular components to maintain cell metabolism. Here, we describe some recent findings that suggest GBM tumors are more sensitive to the excessive overactivation of autophagy leading to autophagy-dependent cell death. GBM cancer stem cells (GSCs) are a subset of the GBM tumor population that play critical roles in tumor formation and progression, metastasis, and relapse, and they are inherently resistant to most therapeutic strategies. Evidence suggests that GSCs are able to adapt to a tumor microenvironment of hypoxia, acidosis, and lack of nutrients. These findings have suggested that autophagy may promote and maintain the stem-like state of GSCs as well as their resistance to cancer treatment. However, autophagy is a double-edged sword and may have anti-tumor properties under certain conditions. The role of the STAT3 transcription factor in autophagy is also described. These findings provide the basis for future research aimed at targeting the autophagy-dependent pathway to overcome the inherent therapeutic resistance of GBM in general and to specifically target the highly therapy-resistant GSC population through autophagy regulation.

HRD1 Promotes Non-small Cell Lung Carcinoma Metastasis by Blocking Autophagy-mediated MIEN1 Degradation

Dysregulation of autophagy has been implicated in the development of many diseases, including cancer. Here, we revealed a novel function of the E3 ubiquitin ligase HRD1 in non-small cell lung carcinoma (NSCLC) metastasis by regulating autophagy. Mechanistically, HRD1 inhibits autophagy by promoting ATG3 ubiquitination and degradation. Additionally, a pro-migratory and invasive factor, MIEN1 (migration and invasion enhancer 1), was found to be autophagically degraded upon HRD1 deficiency. Importantly, both HRD1 and MIEN1 expression are upregulated and positively correlated in lung tumors. Based on these results, we proposed a novel mechanism of HRD1 function that the degradation of ATG3 protein by HRD1 leads to autophagy inhibition and MIEN1 release, thus promoting NSCLC metastasis. Therefore, our findings provided new insights into the role of HRD1 in NSCLC metastasis and new therapeutic targets for lung cancer treatment.

Bromodomain and Extraterminal Domain (BET) Protein Inhibition Hinders Glioblastoma Progression by Inducing Autophagy-Dependent Differentiation

Glioblastoma multiforme (GBM) is the most common and aggressive type of malignant primary brain tumor, and it is characterized by a high recurrence incidence and poor prognosis due to the presence of a highly heterogeneous mass of stem cells with self-renewal capacity and stemness maintenance ability. In recent years, the epigenetic landscape of GBM has been explored and many epigenetic alterations have been investigated. Among the investigated epigenetic abnormalities, the bromodomain and extra-terminal domain (BET) chromatin readers have been found to be significantly overexpressed in GBM. In this work, we investigated the effects of BET protein inhibition on GBM cell reprogramming. We found that the pan-BET pharmacological inhibitor JQ1 was able to promote a differentiation program in GBM cells, thus impairing cell proliferation and enhancing the toxicity of the drug Temozolomide (TMZ). Notably, the pro-differentiation capability of JQ1 was prevented in autophagy-defective models, suggesting that autophagy activation is necessary for BET protein activity in regulating glioma cell fate. Given the growing interest in epigenetic therapy, our results further support the possibility of introducing a BET-based approach in GBM clinical management.

Autoimmunity and Carcinogenesis: Their Relationship under the Umbrella of Autophagy

The immune system and autophagy share a functional relationship. Both innate and adaptive immune responses involve autophagy and, depending on the disease’s origin and pathophysiology, it may have a detrimental or positive role on autoimmune disorders. As a “double-edged sword” in tumors, autophagy can either facilitate or impede tumor growth. The autophagy regulatory network that influences tumor progression and treatment resistance is dependent on cell and tissue types and tumor stages. The connection between autoimmunity and carcinogenesis has not been sufficiently explored in past studies. As a crucial mechanism between the two phenomena, autophagy may play a substantial role, though the specifics remain unclear. Several autophagy modifiers have demonstrated beneficial effects in models of autoimmune disease, emphasizing their therapeutic potential as treatments for autoimmune disorders. The function of autophagy in the tumor microenvironment and immune cells is the subject of intensive study. The objective of this review is to investigate the role of autophagy in the simultaneous genesis of autoimmunity and malignancy, shedding light on both sides of the issue. We believe our work will assist in the organization of current understanding in the field and promote additional research on this urgent and crucial topic.

Capilliposide B inhibits the migration of prostate cancer by inducing autophagy through the ROS/AMPK/mTOR pathway

Capilliposide B (CPS-B), a novel oleanane triterpenoid saponin derived from Lysimachia capillipes Hemsl, is a potent anticancer agent. However, its anticancer mechanism remains elusive. In the present study, we demonstrated the potent anti-tumor activity and molecular mechanism of CPS-B both in vitro and in vivo. Proteomic analysis using isobaric tags for relative and absolute quantitation techniques suggested that CPS-B modulated autophagy in prostate cancer (PC). Moreover, Western blotting showed that both autophagy and epithelial-mesenchymal transition occurred place after CPS-B treatment in vivo, which was also proven in PC-3 cancer cells. We deduced that CPS-B inhibited migration by inducing autophagy. We examined the accumulation of reactive oxygen species (ROS) in cells, and in downstream pathways, LKB1 and AMPK were activated while mTOR was inhibited. Transwell experiment results showed that CPS-B inhibited the metastasis of PC-3 cells and that this effect was significantly attenuated after pretreatment with chloroquine, indicating that CPS-B inhibited metastasis via autophagy induction. Altogether, these data suggest that CPS-B is a potential therapeutic agent for cancer treatment that acts by inhibiting migration through the ROS/AMPK/mTOR signaling pathway.

Licochalcone A Suppresses Renal Cancer Cell Proliferation and Metastasis by Engagement of Sp1-Mediated LC3 Expression

Licochalcone A (LicA) is a strong anti-inflammatory, antioxidant, and anticarcinogenic substance that is useful against a variety of human malignancies. However, its precise mechanism in mediating the development of renal cell carcinoma (RCC) is not entirely understood. In this work, LicA was discovered to limit cell growth and survival, induce cell cycle arrest, promote autophagy and LC3B expression, and inhibit the migration and invasion of RCC cells. In addition, the proliferation, migration, and invasion inhibited by LicA were restored by the transfection of siRNA-LC3. The effects of LC3B on the metastatic phenotype of ACHN cells was enhanced with the overexpression of Sp1 or suppressed by inhibiting the phosphorylation of FAK and Src. Finally, LicA showed antitumor properties against RCC in an in vivo xenograft model. In conclusion, our study demonstrated the chemotherapeutic potential of LicA on proliferation, migration, invasion, and autophagy through the activation of LC3B expression, ultimately modulating FAK/Src signaling pathway-mediated Sp1 expression. These findings illustrate the novel role and molecular mechanisms of LicA against RCC cells.

Autophagy: A challengeable paradox in cancer treatment

OBJECTIVE

Autophagy is an intracellular degradation pathway conserved in all eukaryotes from yeast to humans. This process plays a quality-control role by destroying harmful cellular components under normal conditions, maintaining cell survival, and establishing cellular adaptation under stressful conditions. Hence, there are various studies indicating dysfunctional autophagy as a factor involved in the development and progression of various human diseases, including cancer. In addition, the importance of autophagy in the development of cancer has been highlighted by paradoxical roles, as a cytoprotective and cytotoxic mechanism. Despite extensive research in the field of cancer, there are many questions and challenges about the roles and effects suggested for autophagy in cancer treatment. The aim of this study was to provide an overview of the paradoxical roles of autophagy in different tumors and related cancer treatment options.

METHODS

In this study, to find articles, a search was made in PubMed and Google scholar databases with the keywords Autophagy, Autophagy in Cancer Management, and Drug Design.

RESULTS

According to the investigation, some studies suggest that several advanced cancers are dependent on autophagy for cell survival, so when cancer cells are exposed to therapy, autophagy is induced and suppresses the anti-cancer effects of therapeutic agents and also results in cell resistance. However, enhanced autophagy from using anti-cancer drugs causes autophagy-mediated cell death in several cancers. Because autophagy also plays roles in both tumor suppression and promotion further research is needed to determine the precise mechanism of this process in cancer treatment.

CONCLUSION

We concluded in this article, autophagy manipulation may either promote or hinder the growth and development of cancer according to the origin of the cancer cells, the type of cancer, and the behavior of the cancer cells exposed to treatment. Thus, before starting treatment it is necessary to determine the basal levels of autophagy in various cancers.

Knockdown of miR-150-5p reduces hypoxia-induced autophagy and epithelial-mesenchymal transition of endometriotic cells via regulating the PDCD4/NF-κB signaling pathway

BACKGROUND

Hypoxia is an important microenvironmental factor that induces Endometriosis (EMs), but its mechanism remains unclear. Our study aims to investigate the mechanisms of miR-150-5p on hypoxia-induced EMs.

METHODS

Ovarian endometriosis cyst wall stromal cell lines CRL-7566 cells were treated with hypoxia. Cell migration ability was measured by Transwell assay. qRT-PCR was performed to detect miR-150-5p and PDCD4 expression. The autophagy-related proteins (LC3-I, LC3-II, Beclin-1, and p62), epithelial-mesenchymal transition (EMT) related proteins (E-cadherin, N-cadherin, and Vimentin) and NF-κB signaling pathway related proteins p65 expression were measured by western blot. Dual-luciferase reporter gene assay verified the binding relationship between miR-150-5p and PDCD4.

RESULTS

After hypoxia treatment, the miR-150-5p expression was up-regulated in CRL-7566 cells, while the expression of PDCD4 was down-regulated. In CRL-7566 cells, autophagy, migration and EMT were increased after hypoxia treatment. The autophagy inhibitor 3-MA inhibited hypoxia-induced the autophagy, migration and EMT of CRL-7566 cells. Hypoxia-induced autophagy and EMT of CRL-7566 cells were inhibited after knocking down miR-150-5p. Then miR-150-5p negatively regulated PDCD4 expression. PDCD4 knockdown reversed the inhibitory effect of miR-150-5p silencing on hypoxia-induced autophagy and EMT of CRL-7566 cells. Inhibiting the NF-κB signaling pathway weakened the effect of PDCD4 knockdown on hypoxia-induced autophagy and EMT of CRL-7566 cells.

CONCLUSION

MiR-150-5p silencing inhibited hypoxia-induced autophagy and EMT of endometriotic cells by regulating the PDCD4/NF-κB signaling pathway.

Epithelial-to-mesenchymal transition as a learning paradigm of cell biology

Epithelial-to-mesenchymal transition (EMT) is a complex biological process that occurs during normal embryogenesis and in certain pathological conditions, particularly in cancer. EMT can be viewed as a cell biology-based process, since it involves all the cellular components, including the plasma membrane, cytoskeleton and extracellular matrix, endoplasmic reticulum, Golgi apparatus, lysosomes, and mitochondria, as well as cellular processes, such as regulation of gene expression and cell cycle, adhesion, migration, signaling, differentiation, and death. Therefore, we propose that EMT could be used to motivate undergraduate medical students to learn and understand cell biology. Here, we describe and discuss the involvement of each cellular component and process during EMT. To investigate the density with which different cell biology concepts are used in EMT research, we apply a bibliometric approach. The most frequent cell biology topics in EMT studies were regulation of gene expression, cell signaling, cell cycle, cell adhesion, cell death, cell differentiation, and cell migration. Finally, we suggest that the study of EMT could be incorporated into undergraduate disciplines to improve cell biology understanding among premedical, medical and biomedical students.

Heat treatment-induced autophagy promotes breast cancer cell invasion and metastasis via TGF-β2-mediated epithelial-mesenchymal transitions

Background

Insufficient thermal ablation can accelerate malignant behaviors and metastases in some solid tumors, and epithelial-mesenchymal transition (EMT) and autophagy are involved in tumor metastasis. It has been found that TGF-β2 which belongs to the family of transforming growth factors often associated with cancer cell invasiveness and EMT. However, whether the interactions between autophagy and TGF-β2 induce EMT in breast cancer (BC) cells following insufficient microwave ablation (MWA) remains unclear.

Methods

BC cells were treated with sublethal heat treatment to simulate insufficient MWA, and the effects of heat treatment on the BC cell phenotypes were explored. CCK-8, colony formation, flow cytometry, Transwell, and wound healing assays were performed to evaluate the influence of sublethal heat treatment on the proliferation, apoptosis, invasion, and migration of BC cells. Western blotting, real-time quantitative PCR, immunofluorescence, and transmission electron microscopy were carried out to determine the changes in markers associated with autophagy and EMT following sublethal heat treatment.

Results

Results showed that heat treatment promoted the proliferation of surviving BC cells, which was accompanied by autophagy induction. Heat treatment-induced autophagy up-regulated TGF-β2/Smad2 signaling and promoted EMT phenotype, thereby enhancing BC cells' migration and invasion abilities. An increase or decrease of TGF-β2 expression resulted in the potentiation and suppression of autophagy, as well as the enhancement and abatement of EMT. Autophagy inhibitors facilitated apoptosis and repressed proliferation of BC cells in vitro, and thwarted BC cell tumor growth and pulmonary metastasis in vivo.

Conclusion

Heat treatment-induced autophagy promoted invasion and metastasis via TGF-β2/Smad2-mediated EMTs. Suppressing autophagy may be a suitable strategy for overcoming the progression and metastasis of residual BC cells following insufficient MWA.

Guggulsterone inhibits migration and invasion through proteasomal and lysosomal degradation in human glioblastoma cells

Glioblastoma multiforme (GBM) is a deadly brain malignancy, and current therapies offer limited survival benefit. The phytosterol guggulsterone (GS) has been shown to exhibit antitumor efficacy. This study aimed to investigate the effects of GS on migration and invasion and its underlying mechanisms in human GBM cell lines. After GS treatment, the survival rate of GBM cells was reduced, and the migration and invasion abilities of GBM cells were significantly decreased. There was also concomitant decreased expression of focal adhesion complex, matrix metalloproteinase-2 (MMP2), MMP9 and cathepsin B. Furthermore, GS induced ERK phosphorylation and autophagy, with increased p62 and LC3B-II expression. Notably, treatment of in GBM cells with the proteasome inhibitor MG132 or the lysosome inhibitor NH4Cl reversed the GS-mediated inhibition of migration and invasion. In an orthotopic xenograft mouse model, immunohistochemical staining of brain tumor tissues demonstrated that MMP2 and cathepsin B expression was reduced in GS-treated mice. GS treatment inhibited GBM cell migration and invasion via proteasomal and lysosomal degradation, suggesting its therapeutic potential in clinical use in the future.

HERPUD1 promotes ovarian cancer cell survival by sustaining autophagy and inhibit apoptosis via PI3K/AKT/mTOR and p38 MAPK signaling pathways

HERPUD1 is an important early marker of endoplasmic reticulum stress (ERS) and is involved in the ubiquitination and degradation of several unfolded proteins. However, its role in tumorigenesis is seldom studied, and its role in ovarian cancer is unclear. Lewis y antigen is a tumor-associated sugar antigen that acts as an 'antenna' on the cell surface to receive signals from both inside and outside the cell. We previously reported that Lewis y can promote ovarian cancer by promoting autophagy and inhibiting apoptosis. In this study, we detect the expression of HERPUD1 and Lewis y antigens in 119 different ovarian cancer tissues, determine their relationship with clinicopathological parameters, analyze the correlation between these two proteins, and explore the related cancer-promoting mechanisms through MTT, flow cytometry, western blotting, and bioinformatics. HERPUD1 is highly expressed in ovarian cancer, especially in the early stage, and the expression of HERPUD1 and Lewis y antigen was positively correlated. After overexpression of Lewis y antigen, the expression level of HERPUD1 increased. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathways (KEGG) analysis showed that HERPUD1 and its related genes are enriched in regulating immunity, endoplasmic reticulum stress, ubiquitin-dependent degradation, ERS-induced apoptosis, and other key signaling pathways. We also clarified the HERPUD1 network of kinases, microRNA and transcription factor targets, and the impact of HERPUD1 mutations on prognosis. In addition, HERPUD1 promotes the proliferation of ovarian cancer cells, inhibits apoptosis, affects the cell cycle, promotes the occurrence of autophagy, and inhibits EMT and PI3K/AKT/mTOR and p38MAPK pathways. Overall, HERPUD1, regulated by the expression of tumor-associated protein Lewis y, promotes cell survival in the early stages of tumors, suggesting that HERPUD1 may play an important role in the development of ovarian cancer.

The Challenge of Dimethyl Fumarate Repurposing in Eye Pathologies

Dimethyl fumarate (DMF) is a small molecule currently approved and used in the treatment of psoriasis and multiple sclerosis due to its immuno-modulatory, anti-inflammatory, and antioxidant properties. As an Nrf2 activator through Keap1 protein inhibition, DMF unveils a potential therapeutical use that is much broader than expected so far. In this comprehensive review we discuss the state-of-art and future perspectives regarding the potential repositioning of this molecule in the panorama of eye pathologies, including Age-related Macular Degeneration (AMD). The DMF's mechanism of action, an extensive analysis of the in vitro and in vivo evidence of its beneficial effects, together with a search of the current clinical trials, are here reported. Altogether, this evidence gives an overview of the new potential applications of this molecule in the context of ophthalmological diseases characterized by inflammation and oxidative stress, with a special focus on AMD, for which our gene-disease (KEAP1-AMD) database search, followed by a protein-protein interaction analysis, further supports the rationale of DMF use. The necessity to find a topical route of DMF administration to the eye is also discussed. In conclusion, the challenge of DMF repurposing in eye pathologies is feasible and worth scientific attention and well-focused research efforts.

SAR1A regulates the RhoA/YAP and autophagy signaling pathways to influence osteosarcoma invasion and metastasis

Osteosarcoma is the most prevalent form of primary bone malignancy affecting adolescents. Secretion-associated Ras-related GTPase 1A (SAR1A) is a key regulator of endoplasmic reticulum (ER) homeostasis, but its role as a regulator of osteosarcoma metastasis has yet to be clarified. Bioinformatics analyses revealed SAR1A and RHOA to be upregulated in osteosarcoma patients, with the upregulation of these genes being associated with poor 5-year metastasis-free survival rates. In addition, the upregulation of SAR1A and RHOA in osteosarcoma was highly positively correlated. Immunohistochemical analyses additionally revealed that SAR1A levels were increased in osteosarcoma pulmonary metastases. In vitro wound healing and Transwell assays indicated that knocking down SAR1A or RHOA impaired the invasive and migratory activity of osteosarcoma cells, whereas RHOA overexpression had the opposite effect. Western blotting and immunofluorescent staining revealed the inhibition of osteosarcoma cell epithelial-mesenchymal transition following SAR1A or RHOA knockdown; RHOA overexpression had the opposite effect. Following SAR1A knockdown, phalloidin staining indicated that osteosarcoma cells showed reduced lamellipodia formation. Endoplasmic reticulum stress levels and reactive oxygen species production were enhanced following the knockdown of SAR1A, as was autophagic activity, with lung metastases being reduced in vivo after such knockdown. Knocking down SAR1A suppresses osteosarcoma cell metastasis through the RhoA/YAP, ER stress, and autophagic pathways, offering new insights into the regulation of autophagic activity in the context of osteosarcoma cell metastasis and suggesting that these pathways could be amenable to therapeutic intervention.

Co-targeting triple-negative breast cancer cells and endothelial cells by metronomic chemotherapy inhibits cell regrowth and migration via downregulation of the FAK/VEGFR2/VEGF axis and autophagy/apoptosis activation

High-dose standard-of-care chemotherapy is the only option for triple-negative breast cancer (TNBC) patients, which eventually die due to metastatic tumors. Recently, metronomic chemotherapy (mCHT) showed advantages in treating TNBCs leading us to investigate the anti-metastatic and anti-angiogenic potential of metronomic 5-Fluorouracil plus Vinorelbine (5-FU+VNR) on endothelial cells (ECs) and TNBCs in comparison to standard treatment (STD). We found that 10-fold lower doses of 5-FU+VNR given mCHT vs. STD inhibits cell proliferation and survival of ECs and TNBC cells. Both schedules strongly affect ECs migration and invasion, but in TNBC cells mCHT is significantly more effective than STD in impairing cell migration and invasion. The two treatments disrupt FAK/VEGFR/VEGF signaling in both ECs and TNBC cells. mCHT, and to a much lesser extent STD treatment, induces apoptosis in ECs, whereas it switches the route of cell death from apoptosis (as induced by STD) to autophagy in TNBC cells. mCHT-treated TNBCs-derived conditioned medium also strongly affects ECs' migration, modulates different angiogenesis-associated proteins, and hampers angiogenesis in matrix sponge in vivo. In conclusion, mCHT administration of 5-FU+VNR is more effective than STD schedule in controlling cell proliferation/survival and migration/invasion of both ECs and TNBC cells and has a strong anti-angiogenic effect. Our data suggest that the stabilization of tumor growth observed in TNBC patients treated with mCHT therapy schedule is likely due not only to direct cytotoxic effects but also to anti-metastatic and anti-angiogenic effects.

d-Borneol enhances cisplatin sensitivity via autophagy dependent EMT signaling and NCOA4-mediated ferritinophagy

BACKGROUND

d-Borneol has been widely used as a drug absorption enhancer, but there are few studies on the anti-resistance ability of d-borneol combined with cisplatin in cisplatin-resistant non-small cell lung cancer cells. Ferroptosis, autophagy and epithelial-mesenchymal transition (EMT) have been reported to be associated with drug resistance.

PURPOSE

To investigate the molecular mechanisms and sensitizing effects of d-borneol combined with cisplatin to against drug cisplatin resistance from the perspective of ferroptosis, autophagy and EMT resistance.

METHODS

H460/CDDP xenograft tumor model was established to verify the antitumor activity and safety in vivo. RNA sequencing was used to predict target molecules and signaling pathways. Reactive oxygen species (ROS) were used as marker of ferroptosis, and its level was determined by a dichlorodihydrofluorescein diacetate fluorescent probe and flow cytometry. Levels of glutathione (GSH), malondialdehyde (MDA), and antioxidants such as superoxide dismutase (SOD) and thioredoxin (Trx) involved in the balance of oxidative stress were measured by an assay kit or enzyme-linked immunosorbent assay. Western blotting and real-time polymerase chain reaction were used to assess the regulatory mechanism of EMT markers, autophagy, and ferroptosis signaling pathways.

RESULTS

d-Borneol in combination with cisplatin reduced tumor volume and weight, enhanced tumor-inhibiting effects, and alleviated cisplatin-induced damage to the liver and kidney in vivo. RNA-sequencing showed that differentially expressed genes were enriched in ferroptosis. d-Borneol in combination with cisplatin promoted ROS accumulation, increased the content of MDA levels, and decreased GSH, SOD, Trx, and heme oxygenase-1 expression to induce oxidative damage. d-Borneol combination with cisplatin induced ferroptosis by promoting nuclear receptor coactivator 4 (NCOA4)-mediated ferritinophagy and regulating intracellular iron ion transport via upregulating PRNP and downregulating PCBP2. In addition, d-borneol combined with cisplatin promoted autophagy by upregulating expression of LC3II/ATG5/Beclin-1 and inhibited the EMT by increasing the expression of epithelial marker E-cadherin and decreasing mesenchymal markers (N-cadherin and vimentin) and transcription factors (Snail and ZEB1).

CONCLUSION

For the first time, our study implies that d-borneol enhanced cisplatin sensitivity by inducing ferroptosis, promoting autophagy and inhibiting EMT progression, thereby enhancing antitumor activity. It suggests that d-borneol could be developed as a novel chemosensitizers.

Emerging trends and research foci of epithelial–mesenchymal transition in gliomas: A scientometric analysis and review

Background

Epithelial–mesenchymal transition (EMT) is a key factor in the invasion and migration of glioma cells, and the study of EMT in gliomas has become a hot topic over the past decade. Scientometric analysis is gaining more attention since it can obtain hot topics and emerging trends in a research field. This article analyzed the research related to EMT in gliomas for the first time, including descriptions of research situations, evaluations of research foci, and predictions of emerging trends.

Methods

We searched the topic-related original articles from January 2012 to December 2021 in the Web of Science Core Collection (WoSCC) by using a specific strategy, and a total of 1,217 publications were obtained. The WoS platform, VOS viewer, and CiteSpace were used to analyze the annual distribution of publications and citations, authors and density of keywords, and other analyses including countries, institutions, references, clustering, burst analysis, and the timeline view of keywords.

Results

Scientometric analysis identified that the study of EMT in gliomas has developed fast and received continuous attention in the last decade. Based on the results of data analysis, most publications on the topic came from China, and the United States had the highest betweenness centrality. The top 10 co-cited references revealed the landmark documents that had greatly promoted the development of this field. The major focus is on the cellular and molecular mechanisms of EMT in gliomas, and the therapy related to EMT target and non-coding RNAs has been developing fast in recent years.

Conclusions

This study revealed the intimate connections between EMT and gliomas, and the complex mechanisms regulating EMT in gliomas had been studied widely in the last decade. Exploring the deep mechanisms of EMT in gliomas is the foundation of the targeted inhibitions, which can promote the development of therapies for gliomas.

Capsaicin inhibits the migration, invasion and EMT of renal cancer cells by inducing AMPK/mTOR-mediated autophagy

Capsaicin (CAP), extracted from Capsicum fruits, has been reported to exhibit antitumor effects in various lines of cancer cells. However, the mechanism underlying its antitumor efficiency is not fully understood. Autophagy is a fundamental self-degradation process of cells that maintains homeostasis and plays a controversial role in tumor initiation and progression. The EMT is defined as a system regulating cells transformed from an epithelial-like phenotype into a mesenchymal phenotype by several internal and external factors, following the metastatic performance of the cells developed. The present study aimed to investigate the potential role of autophagy in CAP-induced antitumor effects in renal cell carcinoma (RCC) 786-O and CAKI-1 cell lines. The results revealed that CAP remarkably inhibited the migration and invasion of RCC cells in vitro and metastasis in vivo. Moreover, we found that the CAP treatment increased the formation of autophagolysosome vacuoles and LC3 yellow and red fluorescent puncta in RCC cells and upregulated the expression of LC3, suggesting that autophagy was induced by CAP in 786-O and CAKI-1 cell lines. Our further results demonstrated that CAP-induced autophagy was mediated by the AMPK/mTOR pathway. In conclusion, our study provides new knowledge of the potential relationship between autophagy and metastasis inhibition induced by CAP, which might be a promising therapeutic strategy in RCC.

Is extremely low frequency pulsed electromagnetic fields applicable to gliomas? A literature review of the underlying mechanisms and application of extremely low frequency pulsed electromagnetic fields

Gliomas refer to a group of complicated human brain tumors with a low 5-year survival rate and limited therapeutic options. Extremely low-frequency pulsed electromagnetic field (ELF-PEMF) is a specific magnetic field featuring almost no side effects. However, the application of ELF-PEMF in the treatment of gliomas is rare. This review summarizes five significant underlying mechanisms including calcium ions, autophagy, apoptosis, angiogenesis, and reactive oxygen species, and applications of ELF-PEMF in glioma treatment from a clinical practice perspective. In addition, the prospects of ELF-PEMF in combination with conventional therapy for the treatment of gliomas are reviewed. This review benefits any specialists, especially oncologists, interested in this new therapy because it can help treat patients with gliomas properly.

A review of the effects of estrogen and epithelial-mesenchymal transformation on intrauterine adhesion and endometriosis

Uterus transplantation has become an option for women suffering from some form of infertility. Current review discusses key physiological functions of the endometrium requiring the transition of tissue cells between the mesenchyme and epithelial cell phenotype, a process known as epithelial-mesenchymal transition (EMT). Estrogen and EMT play a key role in the pathogenesis and treatment of intrauterine adhesion and endometriosis. There is also a close regulatory relationship between estrogen and EMT, and investigation of this relationship is of great significance for the treatment of endometrial disorders. The present review discusses the effects of estrogen on endometrial dysfunction, with a focus on the relationship between estrogen and EMT in endometrial disorders, taking into consideration the mechanisms by which receptors that regulate their functions and proteins that regulate their local biological functions interact with the factors involved in EMT. In addition, the review summarizes emerging drugs targeting receptors or proteins and provides information on the direction of new therapies for endometrial disorders.

High Glucose Accelerates Tumor Progression by Regulating MEDAG-Mediated Autophagy Levels in Breast Cancer

Recent studies have shown that diabetes is a major risk factor for breast cancer (BC), but the mechanism is incompletely understood. Mesenteric estrogen-dependent adipogenesis (MEDAG) plays a significant role in both glucose uptake and BC development. However, the relationship between MEDAG and BC under high glucose (HG) conditions remains unclear. In our study, MEDAG expression was higher in BC tissue from diabetic patients than in BC tissue from nondiabetic patients. HG promoted BC progression in vitro and in vivo by upregulating MEDAG expression. Furthermore, MEDAG deficiency increased the autophagosome number and autophagic flux. Moreover, inhibition of autophagy partially reversed MEDAG knockdown (MEDAG^KD)-induced suppression of tumorigenic biological behaviors and epithelial-mesenchymal transition (EMT) progression. Finally, MEDAG significantly suppressed AMPK phosphorylation. Additionally, the AMPK inhibitor Compound C markedly reduced autophagosome accumulation and antitumor effects in MEDAG^KD cells. Treatment with the AMPK activator AICAR exhibited similar effects in MEDAG-overexpressing (MEDAG^OE) cells. In conclusion, the MEDAG-AMPK-autophagy axis is vital to BC progression in diabetic patients. Our findings provide a novel treatment target for BC in patients with diabetes.

Paeoniflorin Inhibits EMT and Angiogenesis in Human Glioblastoma via K63-Linked C-Met Polyubiquitination-Dependent Autophagic Degradation

Epithelial-to-mesenchymal transition (EMT) and angiogenesis have emerged as two pivotal events in cancer progression. Paeoniflorin has been widely studied in experimental models and clinical trials for cancer treatment because of its anti-cancer property. However, the underlying mechanisms of paeoniflorin in EMT and angiogenesis in glioblastoma was not fully elucidated. The present study aimed to investigate whether paeoniflorin inhibits EMT and angiogenesis, which involving c-Met suppression, while exploring the potential ways of c-Met degradation. In our study, we found that paeoniflorin inhibited EMT via downregulating c-Met signaling in glioblastoma cells. Furthermore, overexpressing c-Met in glioblastoma cells abolished the effects of paeoniflorin on EMT. Moreover, paeoniflorin showed anti-angiogenic effects by suppressing cell proliferation, migration, invasion and tube formation through downregulating c-Met in human umbilical vein endothelial cells (HUVECs). And c-Met overexpression in HUVECs offset the effects of paeoniflorin on angiogenesis. Additionally, paeoniflorin induced autophagy activation involving mTOR/P70S6K/S6 signaling and promoted c-Met autophagic degradation, a process dependent on K63-linked c-Met polyubiquitination. Finally, paeoniflorin suppressed mesenchymal makers (snail, vimentin, N-cadherin) and inhibited angiogenesis via the identical mechanism in an orthotopic xenograft mouse model. The in vitro and in vivo experiments showed that paeoniflorin treatment inhibited EMT, angiogenesis and activated autophagy. What’s more, for the first time, we identified c-Met may be a potential target of paeoniflorin and demonstrated paeoniflorin downregulated c-Met via K63-linked c-Met polyubiquitination-dependent autophagic degradation. Collectively, these findings indicated that paeoniflorin inhibits EMT and angiogenesis via K63-linked c-Met polyubiquitination-dependent autophagic degradation in human glioblastoma.

Resveratrol and Its Analogue 4,4′-Dihydroxy-trans-stilbene Inhibit Lewis Lung Carcinoma Growth In Vivo through Apoptosis, Autophagy and Modulation of the Tumour Microenvironment in a Murine Model

Lung cancer is the most prevalent cancer worldwide. Despite advances in surgery and immune-chemotherapy, the therapeutic outcome remains poor. In recent years, the anticancer properties of natural compounds, along with their low toxic side effects, have attracted the interest of researchers. Resveratrol (RSV) and many of its derivatives received particular attention for their beneficial bioactivity. Here we studied the activity of RSV and of its analogue 4,4′-dihydroxystilbene (DHS) in C57BL/6J mice bearing cancers resulting from Lung Lewis Carcinoma (LLC) cell implantation, considering tumour mass weight, angiogenesis, cell proliferation and death, autophagy, as well as characterization of their immune microenvironment, including infiltrating cancer-associated fibroblasts (CAFs). C57BL/6J mice started treatment with RSV or DHS, solubilised in drinking water, one week before LLC implantation, and continued for 21 days, at the end of which they were sacrificed, and the tumour masses collected. Histology was performed according to standard procedures; angiogenesis, cell proliferation and death, autophagy, infiltrating-immune cells, macrophages and fibroblasts were assessed by immunodetection assays. Both stilbenic compounds were able to contrast the tumour growth by increasing apoptosis and autophagy in LLC tumour masses. Additionally, they contrasted the tumour-permissive microenvironment by limiting the infiltration of tumour-associated immune-cells and, more importantly, by counteracting CAF maturation. Therefore, both stilbenes could be employed to synergise with conventional oncotherapies to limit the contribution of stromal cells in tumour growth.

Autophagy deficiency promotes lung metastasis of prostate cancer via stabilization of TWIST1

PURPOSE

The role of autophagy in prostate cancer metastasis remains controversial, and the effects of the autophagy-related gene ATG5 on prostate cancer metastasis are poorly understood. This study aims to explore the effects of ATG5 on prostate cancer metastasis and its molecular mechanism.

METHODS

The metastatic characteristics of LNCaP and DU145 cells were assessed by NOD/SCID mouse experiments, western blot, transwell assay, and wound-healing assay. Double membrane autophagic vesicle observation and the adenovirus-expressing mCherry-GFP-LC3B fusion protein were used to assess the autophagic characteristics of LNCaP and DU145 cells. The role of p62 in the accumulation of TWIST1 was confirmed by western blot under different conditions. The lentivirus particles of shATG5, NOD/SCID mice experiments, western blot, transwell assay, and wound-healing assay were used to confirm the role of ATG5 in TWIST1 accumulation and prostate cancer cell metastasis.

RESULTS

We identified a stabilizing effect of p62 on TWIST1 in the autophagic regulation of EMT and prostate cancer metastasis. The loss of ATG5 in DU145 cells resulted in autophagy deficiency and p62 accumulation, which stabilized TWIST1 and increased the TWIST1 level in prostate cancer cells, and eventually promoted EMT and metastasis. In comparison, LNCaP cells with regular ATG5 expression and autophagy status retained remarkable epithelial cell characteristics and had limited metastatic characteristics. Similar results were also found in wild-type LNCaP cells and LNCaP cells with stable ATG5 interference.

CONCLUSIONS

Our research revealed ATG5-mediated autophagy as a key mechanism that controls the metastasis of prostate cancer by regulating p62 abundance and TWIST1 stabilization.

Interaction between tumor microenvironment, autophagy, and epithelial-mesenchymal transition in tumor progression

Tumor microenvironment (TME) is the ecosystem surrounding a tumor to influence tumor cells' growth, metastasis and immunological battlefield, in which the tumor systems fight against the body system. TME has been considered as the essential link between the tumorigenesis and development of neoplasm. Both nutrients intake and tumor progression to malignancy require the participation of components in TME. Epithelial-mesenchymal transition (EMT) is a key step in the metastasis of tumor cells. Cells that lost polarity and acquired migration ability are prone to metastasize. Autophagy is an important self-protective mechanism in tumor cells and a necessity for the tumor cells to respond to harmful stress. Protective autophagy benefits tumor cells while abnormal autophagy leads to cell injury or death. EMT and autophagy are directly regulated by TME. To date, there are numerous studies on TME, autophagy and EMT separately, but few on their complex interrelationships. This review aims to comprehensively analyze the existing mechanisms and convincing evidence so far to seek novel therapeutic strategies and research directions.

The multifaceted role of autophagy in cancer

Autophagy is a cellular degradative pathway that plays diverse roles in maintaining cellular homeostasis. Cellular stress caused by starvation, organelle damage, or proteotoxic aggregates can increase autophagy, which uses the degradative capacity of lysosomal enzymes to mitigate intracellular stresses. Early studies have shown a role for autophagy in the suppression of tumorigenesis. However, work in genetically engineered mouse models and in vitro cell studies have now shown that autophagy can be either cancer-promoting or inhibiting. Here, we summarize the effects of autophagy on cancer initiation, progression, immune infiltration, and metabolism. We also discuss the efforts to pharmacologically target autophagy in the clinic and highlight future areas for exploration.