DNA damaging agent-induced autophagy produces a cytoprotective adenosine triphosphate surge in malignant glioma cells

Loss of Fanconi anemia proteins causes a reliance on lysosomal exocytosis

Mutations in the FA pathway lead to a rare genetic disease that increases risk of bone marrow failure, acute myeloid leukemia, and solid tumors. FA patients have a 500 to 800-fold increase in head and neck squamous cell carcinoma compared to the general population and the treatment for these malignancies are ineffective and limited due to the deficiency in DNA damage repair. Using unbiased CRISPR-interference screening, we found the loss of FA function renders cells dependent on key exocytosis genes such as SNAP23. Further investigation revealed that loss of FA pathway function induced deficiencies in lysosomal health, dysregulation of autophagy and increased lysosomal exocytosis. The compromised cellular state caused by the loss of FA genes is accompanied with decreased lysosome abundance and increased lysosomal membrane permeabilization in cells. We found these signatures in vitro across multiple cell types and cell lines and in clinically relevant FA patient cancers. Our findings are the first to connect the FA pathway to lysosomal exocytosis and thus expands our understanding of FA as a disease and of induced dependencies in FA mutant cancers.

Metabolic Reprogramming in Glioblastoma Multiforme: A Review of Pathways and Therapeutic Targets

Glioblastoma (GBM) is an aggressive and highly malignant primary brain tumor characterized by rapid growth and a poor prognosis for patients. Despite advancements in treatment, the median survival time for GBM patients remains low. One of the crucial challenges in understanding and treating GBMs involves its remarkable cellular heterogeneity and adaptability. Central to the survival and proliferation of GBM cells is their ability to undergo metabolic reprogramming. Metabolic reprogramming is a process that allows cancer cells to alter their metabolism to meet the increased demands of rapid growth and to survive in the often oxygen- and nutrient-deficient tumor microenvironment. These changes in metabolism include the Warburg effect, alterations in several key metabolic pathways including glutamine metabolism, fatty acid synthesis, and the tricarboxylic acid (TCA) cycle, increased uptake and utilization of glutamine, and more. Despite the complexity and adaptability of GBM metabolism, a deeper understanding of its metabolic reprogramming offers hope for developing more effective therapeutic interventions against GBMs.

Autophagy in aging-related diseases and cancer: Principles, regulatory mechanisms and therapeutic potential

Macroautophagy/autophagy is primarily accountable for the degradation of damaged organelles and toxic macromolecules in the cells. Regarding the essential function of autophagy for preserving cellular homeostasis, changes in, or dysfunction of, autophagy flux can lead to disease development. In the current paper, the complicated function of autophagy in aging-associated pathologies and cancer is evaluated, highlighting the underlying molecular mechanisms that can affect longevity and disease pathogenesis. As a natural biological process, a reduction in autophagy is observed with aging, resulting in an accumulation of cell damage and the development of different diseases, including neurological disorders, cardiovascular diseases, and cancer. The MTOR, AMPK, and ATG proteins demonstrate changes during aging, and they are promising therapeutic targets. Insulin/IGF1, TOR, PKA, AKT/PKB, caloric restriction and mitochondrial respiration are vital for lifespan regulation and can modulate or have an interaction with autophagy. The specific types of autophagy, such as mitophagy that degrades mitochondria, can regulate aging by affecting these organelles and eliminating those mitochondria with genomic mutations. Autophagy and its specific types contribute to the regulation of carcinogenesis and they are able to dually enhance or decrease cancer progression. Cancer hallmarks, including proliferation, metastasis, therapy resistance and immune reactions, are tightly regulated by autophagy, supporting the conclusion that autophagy is a promising target in cancer therapy.

Histone lactylation regulates autophagy of hyperplastic scar fibroblasts by inhibiting the transcriptional activity of phosphatase and tensin homologue

Hyperplastic scar (HS) is an overreaction of tissue to skin injury caused by local fibroblast proliferation and excessive collagen production. Histone posttranslational modification patterns are important epigenetic processes that control various biological activities. This study was designed to investigate the effects of histone lactylation on HS and the underlying mechanism. Western blot was used to analyse the lactylation level in HS patients and fibroblasts (HSFs). In vitro experiments, western blot, cell counting kit-8, and immunofluorescence staining were performed to detect the collagen level, cell viability, and autophagy, respectively. The relationship between snai2 (SLUG) and phosphatase and tensin homologue (PTEN) was assessed by RNA immunoprecipitation and dual-luciferase reporter assays. The results showed that the histone lactylation level was upregulated in HS tissues and HSFs. HSFs showed increased collagen production and cell viability, and decreased autophagy. Silencing of lactate dehydrogenase A (LDHA) promoted the transcription of PTEN by inhibiting SLUG, thus promoting autophagy. Knockdown of LDHA inhibited collagen deposition and cell viability, and increased autophagy in HSFs, and the results were reversed after PTEN inhibition. In summary, histone lactylation inhibited the transcription activity of PTEN by promoting SLUG, thereby suppressing autophagy and promoting collagen deposition and cell viability of HSFs, which might provide effective therapeutic strategies in HS.

Synthesis of a metal-organic framework Cu-Mi-UiO-66-based fluorescent nanoprobe for the simultaneous sensing and intracellular imaging of GSH and ATP

This study reports a fluorescent nanoprobe operated in fluorescence turn-on mode for simultaneously sensing and imaging intracellular GSH and ATP. By using maleimide-derivatives as the ligand, the bimetallic nanoscale metal-organic framework (NMOF) Cu-Mi-UiO-66 has been synthesized for the first time using a straightforward one-step solvothermal approach, serving as a GSH recognition moiety. Subsequently, a Cy5-labeled ATP aptamer was assembled onto Cu-Mi-UiO-66 via strong coordination between phosphate and zirconium, π-π stacking and electrostatic adsorption to develop the dual-responsive fluorescence nanoprobe Cu-Mi-UiO-66/aptamer. Due to the photoinduced electron transfer (PET) effect between maleimide groups and the benzene ring of the ligand and the charge transfer between Cy5 and the Zr(IV)/Cu(II) bimetal center of the NMOF, the Cu-Mi-UiO-66/aptamer exhibits a fluorescence turn-off status. The Michael addition reaction between the thiol group of GSH and the maleimide on the NMOF skeleton results in turning on of the blue fluorescence of Cu-Mi-UiO-66. Meanwhile, upon specific interaction with ATP, the aptamer changes into internal loop structures and detaches from Cu-Mi-UiO-66, resulting in turning on of the red fluorescence of Cy5. The nanoprobe demonstrated an excellent sensing performance with a good linear range (GSH, 5.0-450.0 μM; ATP, 1.0-50.0 μM) and a low detection limit (GSH, 2.17 μM; ATP, 0.635 μM). More importantly, the Cu-Mi-UiO-66/aptamer exhibits good performance for tracing intracellular concentration variations of GSH and ATP in living HepG2 cells under different stimulations. This study highlights the potential of NMOFs for multiplexed analysis and provides a valuable tool for tumor microenvironment research and early cancer diagnosis.

An Overview of Altered Pathways Associated with Sensitivity to Platinum-Based Chemotherapy in Neuroendocrine Tumors: Strengths and Prospects

Neuroendocrine neoplasms (NENs) are a diverse group of malignancies with a shared phenotype but varying prognosis and response to current treatments. Based on their morphological features and rate of proliferation, NENs can be classified into two main groups with a distinct clinical behavior and response to treatment: (i) well-differentiated neuroendocrine tumors (NETs) or carcinoids (with a low proliferation rate), and (ii) poorly differentiated small- or large-cell neuroendocrine carcinomas (NECs) (with a high proliferation rate). For certain NENs (such as pancreatic tumors, higher-grade tumors, and those with DNA damage repair defects), chemotherapy is the main therapeutic approach. Among the different chemotherapic agents, cisplatin and carboplatin, in combination with etoposide, have shown the greatest efficacy in treating NECs compared to NETs. The cytotoxic effects of cisplatin and carboplatin are primarily due to their binding to DNA, which interferes with normal DNA transcription and/or replication. Consistent with this, NECs, which often have mutations in pathways involved in DNA repair (such as Rb, MDM2, BRCA, and PTEN), have a high response to platinum-based chemotherapy. Identifying mutations that affect molecular pathways involved in the initiation and progression of NENs can be crucial in predicting the response to platinum chemotherapy. This review aims to highlight targetable mutations that could serve as predictors of therapeutic response to platinum-based chemotherapy in NENs.

Programmed cell death disrupts inflammatory tumor microenvironment (TME) and promotes glioblastoma evolution

Glioblastoma (GBM) is the most common malignant brain tumor and has a dismal prognosis even under the current first-line treatment, with a 5-year survival rate less than 7%. Therefore, it is important to understand the mechanism of treatment resistance and develop new anti-tumor strategies. Induction of programmed cell death (PCD) has become a promising anti-tumor strategy, but its effectiveness in treating GBM remains controversial. On the one hand, PCD triggers tumor cell death and then release mediators to draw in immune cells, creating a pro-inflammatory tumor microenvironment (TME). One the other hand, mounting evidence suggests that PCD and inflammatory TME will force tumor cells to evolve under survival stress, leading to tumor recurrence. The purpose of this review is to summarize the role of PCD and inflammatory TME in the tumor evolution of GBM and promising methods to overcome tumor evolution.

Alpha-Hederin induces incomplete autophagic injury in non-small cell lung cancer by interfering with the lysosomal acidification

Lung cancer is the most common oncological disease worldwide, with non-small cell lung cancer accounting for approximately 85% of lung cancer cases. α-Hederin is a monodesmosidic triterpenoid saponin isolated from the leaves of Hedera helix L. or Nigella sativa and has been extensively studied for its antitumor activity against a variety of tumor cells. It has been suggested that α-Hederin is a potential regulator of autophagy and has high promise for application. However, the specific mechanism and characteristics of α-Hederin in regulating autophagy are not well understood. In this study, we confirmed the potential of α-Hederin application in lung cancer treatment and comprehensively explored the mechanism and characteristics of α-Hederin in regulating autophagy in lung cancer cells. Our results suggest that α-Hederin is an incomplete autophagy inducer that targets mTOR to activate the classical autophagic pathway, inhibits lysosomal acidification without significantly affecting the processes of autophagosome transport, lysosome biogenesis, autophagosome and lysosome fusion, and finally leads to impaired autophagic flux and triggers autophagic damage in NSCLC.

Dysregulation of autophagy in gastric carcinoma: Pathways to tumor progression and resistance to therapy

The considerable death rates and lack of symptoms in early stages of gastric cancer (GC) make it a major health problem worldwide. One of the most prominent risk factors is infection with Helicobacter pylori. Many biological processes, including those linked with cell death, are disrupted in GC. The cellular "self-digestion" mechanism necessary for regular balance maintenance, autophagy, is at the center of this disturbance. Misregulation of autophagy, however, plays a role in the development of GC. In this review, we will examine how autophagy interacts with other cell death processes, such as apoptosis and ferroptosis, and how it affects the progression of GC. In addition to wonderful its role in the epithelial-mesenchymal transition, it is engaged in GC metastasis. The role of autophagy in GC in promoting drug resistance stands out. There is growing interest in modulating autophagy for GC treatment, with research focusing on natural compounds, small-molecule inhibitors, and nanoparticles. These approaches could lead to breakthroughs in GC therapy, offering new hope in the fight against this challenging disease.

The Role of Autophagy in Vascular Endothelial Cell Health and Physiology

Autophagy is a highly conserved cellular recycling process which enables eukaryotes to maintain both cellular and overall homeostasis through the catabolic breakdown of intracellular components or the selective degradation of damaged organelles. In recent years, the importance of autophagy in vascular endothelial cells (ECs) has been increasingly recognized, and numerous studies have linked the dysregulation of autophagy to the development of endothelial dysfunction and vascular disease. Here, we provide an overview of the molecular mechanisms underlying autophagy in ECs and our current understanding of the roles of autophagy in vascular biology and review the implications of dysregulated autophagy for vascular disease. Finally, we summarize the current state of the research on compounds to modulate autophagy in ECs and identify challenges for their translation into clinical use.

Investigating autophagy and intricate cellular mechanisms in hepatocellular carcinoma: Emphasis on cell death mechanism crosstalk

Hepatocellular carcinoma (HCC) stands as a formidable global health challenge due to its prevalence, marked by high mortality and morbidity rates. This cancer type exhibits a multifaceted etiology, prominently linked to viral infections, non-alcoholic fatty liver disease, and genomic mutations. The inherent heterogeneity of HCC, coupled with its proclivity for developing drug resistance, presents formidable obstacles to effective therapeutic interventions. Autophagy, a fundamental catabolic process, plays a pivotal role in maintaining cellular homeostasis, responding to stressors such as nutrient deprivation. In the context of HCC, tumor cells exploit autophagy, either augmenting or impeding its activity, thereby influencing tumorigenesis. This comprehensive review underscores the dualistic role of autophagy in HCC, acting as both a pro-survival and pro-death mechanism, impacting the trajectory of tumorigenesis. The anti-carcinogenic potential of autophagy is evident in its ability to enhance apoptosis and ferroptosis in HCC cells. Pertinently, dysregulated autophagy fosters drug resistance in the carcinogenic context. Both genomic and epigenetic factors can regulate autophagy in HCC progression. Recognizing the paramount importance of autophagy in HCC progression, this review introduces pharmacological compounds capable of modulating autophagy-either inducing or inhibiting it, as promising avenues in HCC therapy.

Migrasomal autophagosomes relieve endoplasmic reticulum stress in glioblastoma cells

BACKGROUND

Glioblastoma (GBM) is more difficult to treat than other intractable adult tumors. The main reason that GBM is so difficult to treat is that it is highly infiltrative. Migrasomes are newly discovered membrane structures observed in migrating cells. Thus, they can be generated from GBM cells that have the ability to migrate along the brain parenchyma. However, the function of migrasomes has not yet been elucidated in GBM cells.

RESULTS

Here, we describe the composition and function of migrasomes generated along with GBM cell migration. Proteomic analysis revealed that LC3B-positive autophagosomes were abundant in the migrasomes of GBM cells. An increased number of migrasomes was observed following treatment with chloroquine (CQ) or inhibition of the expression of STX17 and SNAP29, which are involved in autophagosome/lysosome fusion. Furthermore, depletion of ITGA5 or TSPAN4 did not relieve endoplasmic reticulum (ER) stress in cells, resulting in cell death.

CONCLUSIONS

Taken together, our study suggests that increasing the number of autophagosomes, through inhibition of autophagosome/lysosome fusion, generates migrasomes that have the capacity to alleviate cellular stress.

A glimpse into let-7e roles in human disorders; friend or foe?

MicroRNAs (miRNAs) have been linked to abnormal expression and regulation in a number of diseases, including cancer. Recent studies have concentrated on miRNA Let-7e's significance in precision medicine for cancer screening and diagnosis as well as its prognostic and therapeutic potential. Differential let-7e levels in bodily fluids have the possibility to enable early detection of cancer utilizing less-invasive techniques, reducing biopsy-related risks. Although Let-7e miRNAs have been described as tumor suppressors, it is crucial to note that there exists proof to support their oncogenic activity in vitro and in in vivo. Let-7e's significance in chemo- and radiation treatment decisions has also been demonstrated. Let-7e can also prevent the synthesis of proinflammatory cytokines in a number of degenerative disorders, including musculoskeletal and neurological conditions. For the first time, an overview of the significance of let-7e in the prevention, detection, and therapy of cancer and other conditions has been given in the current review. Additionally, we focused on the specific molecular processes that underlie the actions of let-7e, more particularly, on malignant cells.

Upstream open reading frame-encoded MP31 disrupts the mitochondrial quality control process and inhibits tumorigenesis in glioblastoma

BACKGROUND

Mitochondrial hyperpolarization achieved by the elevation of mitochondrial quality control (MQC) activity is a hallmark of glioblastoma (GBM). Therefore, targeting the MQC process to disrupt mitochondrial homeostasis should be a promising approach for GBM therapy.

METHODS

We used 2-photon fluorescence microscopy, Fluorescence-Activated Cell Sorting, and confocal microscopy with specific fluorescent dyes to detect the mitochondrial membrane potential (MMP) and mitochondrial structures. Mitophagic flux was measured with mKeima.

RESULTS

MP31, a phosphatase and tensin homolog (PTEN) uORF-translated and mitochondria-localized micropeptide, disrupted the MQC process and inhibited GBM tumorigenesis. Re-expression of MP31 in patient-derived GBM cells induced MMP loss to trigger mitochondrial fission but blocked mitophagic flux, leading to the accumulation of damaged mitochondria in cells, followed by reactive oxygen species production and DNA damage. Mechanistically, MP31 inhibited lysosome function and blocked lysosome fusion with mitophagosomes by competing with V-ATPase A1 for lactate dehydrogenase B (LDHB) binding to induce lysosomal alkalinization. Furthermore, MP31 enhanced the sensitivity of GBM cells to TMZ by suppressing protective mitophay in vitro and in vivo, but showed no side effects on normal human astrocytes or microglia cells (MG).

CONCLUSIONS

MP31 disrupts cancerous mitochondrial homeostasis and sensitizes GBM cells to current chemotherapy, without inducing toxicity in normal human astrocytes and MG. MP31 is a promising candidate for GBM treatment.

Genetic markers associated with adverse reactions of radioiodine therapy in thyroid cancer patients

OBJECTIVES

Radioactive iodine therapy is considered for patients with certain clinicopathological factors that predict a significant risk of recurrence, distant metastases of thyroid cancer or disease-specific mortality. The aim of the study was to investigate the association between polymorphisms of genes, products of which are involved in the processes of DNA damage response and autophagy, and the adverse reactions of radioiodine therapy in thyroid cancer patients.

METHODS

The study included 181 patients (37 men, 144 women; median age 56 [41; 66.3] years) with histologically confirmed thyroid cancer and a history of thyroidectomy who received radioiodine therapy. NFKB1, ATM, ATG16L2, ATG10, TGFB1, and TNF polymorphisms were determined by allele-specific realtime-PCR.

RESULTS

The frequency of adverse reactions was the following: gastrointestinal symptoms - 57.9 %, local symptoms - 65.8 %, cerebral symptoms - 46.8 %, fatigue - 54.4 %; signs of sialoadenitis six months after radioiodine therapy - 25.2 %. TT genotype carriers of ATG10 rs1864183 had higher frequency of gastrointestinal symptoms (vs. CC+CT), the CC genotype carriers of ATG10 rs10514231 had significantly more frequent cerebral symptoms (vs. CT+TT), as well as AA genotype carriers of TGFB1 rs1800469 (vs. AG+GG). CC genotype of ATG10 rs10514231 increased the incidence of radioiodine-induced fatigue, whereas GA genotype of the ATM rs11212570 had a protective role against fatigue. TGFB1 rs1800469 was associated with signs of sialoadenitis six months after radioiodine therapy.

CONCLUSIONS

Genetic factors may contribute to the occurrence of adverse reactions of radioiodine therapy in thyroid cancer patients.

Genetic markers associated with adverse reactions of radioiodine therapy in thyroid cancer patients

OBJECTIVES

Radioactive iodine therapy is considered for patients with certain clinicopathological factors that predict a significant risk of recurrence, distant metastases of thyroid cancer or disease-specific mortality. The aim of the study was to investigate the association between polymorphisms of genes, products of which are involved in the processes of DNA damage response and autophagy, and the adverse reactions of radioiodine therapy in thyroid cancer patients.

METHODS

The study included 181 patients (37 men, 144 women; median age 56 [41; 66.3] years) with histologically confirmed thyroid cancer and a history of thyroidectomy who received radioiodine therapy. NFKB1, ATM, ATG16L2, ATG10, TGFB1, and TNF polymorphisms were determined by allele-specific realtime-PCR.

RESULTS

The frequency of adverse reactions was the following: gastrointestinal symptoms - 57.9 %, local symptoms - 65.8 %, cerebral symptoms - 46.8 %, fatigue - 54.4 %; signs of sialoadenitis six months after radioiodine therapy - 25.2 %. TT genotype carriers of ATG10 rs1864183 had higher frequency of gastrointestinal symptoms (vs. CC+CT), the CC genotype carriers of ATG10 rs10514231 had significantly more frequent cerebral symptoms (vs. CT+TT), as well as AA genotype carriers of TGFB1 rs1800469 (vs. AG+GG). CC genotype of ATG10 rs10514231 increased the incidence of radioiodine-induced fatigue, whereas GA genotype of the ATM rs11212570 had a protective role against fatigue. TGFB1 rs1800469 was associated with signs of sialoadenitis six months after radioiodine therapy.

CONCLUSIONS

Genetic factors may contribute to the occurrence of adverse reactions of radioiodine therapy in thyroid cancer patients.

Benzo(a)pyrene regulates chaperone-mediated autophagy via heat shock protein 90

AIMS

Some studies have shown that the Benzo(a)pyrene (BaP) exposure induced oxidative damage, DNA damage and autophagy, but the molecular mechanism is not clear. Heat shock protein 90 (HSP90) is regarded as an important target in cancer therapy and a key factor in autophagy. Therefore, this study aims to clarify the new mechanism of BaP regulating CMA through HSP90.

MAIN METHODS

C57BL mice were fed with BaP at a dose of 25.3mg/kg. A549 cells were treated with different concerntrations of BaP, and MTT assay was used to observe the effect of BaP on the proliferation of A549 cells. DNA damage was detected by alkaline comet assay. Focus experiment for detection of γ-H2AX by immunofluorescence. The mRNA expression of HSP90, HSC70 and Lamp-2a was detected by qPCR. The protein expressions of HSP90, HSC70 and Lamp-2a were detected by Western blot. Next, we knocked down HSP90 expression by the HSP90 Inhibitor, NVP-AUY 922, exposed or HSP90α shRNA lentivirus transduction in A549 cells.

KEY FINDINGS

In these studies, we first found that heat shock protein 90 (HSP90), heat shock cognate 70 (HSC70) and lysosomal-associated membrane protein type 2 receptor (Lamp-2a) expressions of C57BL mice lung tissue and A549 cells exposed to BaP were significant increase, as well as BaP induced DNA double-strand breaks (DSBs) and activated DNA damage responses, as evidenced by comet assay and γ-H2AX foci analysis in A549 cells. Our results demonstrated BaP induced CMA and caused DNA damage. Next, we knocked down HSP90 expression by the HSP90 Inhibitor, NVP-AUY 922, exposed or HSP90α shRNA lentivirus transduction in A549 cells. HSC70 and Lamp-2a expressions of these cells exposed to BaP were not significant increase, which showed that BaP inducted CMA was mediated by HSP90. Further, HSP90α shRNA prevented BaP induced of BaP which suggested BaP regulated CMA and caused DNA damage by HSP90. Our results elucidated a new mechanism of BaP regulated CMA through HSP90.

SIGNIFICANCE

BaP regulated CMA through HSP90. HSP90 is involved in the regulation of gene instability induced by DNA damage by BaP, which promotes CMA. Our study also revealed that BaP regulates CMA through HSP90. This study fills the gap of the effect of BaP on autophagy and its mechanism, which will lead to a more comprehensive understanding of the action mechanism of BaP.

Thiophene Carboxamide Analogs with Long Alkyl Chains Comprising Ethylene Glycol Units Inhibit Glioblastoma Cell Proliferation by Activating AMPK

Glioblastoma is a refractory malignant tumor that requires novel therapeutic strategies for effective treatment. We have previously reported that JCI-20679 (1), an analog of annonaceous acetogenins, shows potent antitumor activity against glioblastomas. However, the synthesis of 1 requires 23 steps, including 16 steps for the preparation of a tetrahydrofuran (THF) moiety. This study reports the design and synthesis of 11 analogs with a triethylene glycol moiety in place of the THF moiety in 1. Among these, the analog 2k with an n-decyl chain exhibited potent inhibitory activity against the growth of glioblastoma stem cells by inhibiting mitochondrial function and synergistically enhancing the effect of temozolomide (TMZ). Furthermore, 2k significantly suppressed tumor growth without critical toxicity in vivo. Hence, this study presents novel potential anticancer agents and a strategy for the development of these agents that can be produced easily.

Advanced Bioinformatics Analysis and Genetic Technologies for Targeting Autophagy in Glioblastoma Multiforme

As the most malignant primary brain tumor in adults, a diagnosis of glioblastoma multiforme (GBM) continues to carry a poor prognosis. GBM is characterized by cytoprotective homeostatic processes such as the activation of autophagy, capability to confer therapeutic resistance, evasion of apoptosis, and survival strategy even in the hypoxic and nutrient-deprived tumor microenvironment. The current gold standard of therapy, which involves radiotherapy and concomitant and adjuvant chemotherapy with temozolomide (TMZ), has been a game-changer for patients with GBM, relatively improving both overall survival (OS) and progression-free survival (PFS); however, TMZ is now well-known to upregulate undesirable cytoprotective autophagy, limiting its therapeutic efficacy for induction of apoptosis in GBM cells. The identification of targets utilizing bioinformatics-driven approaches, advancement of modern molecular biology technologies such as clustered regularly interspaced short palindromic repeats (CRISPR)—CRISPR-associated protein (Cas9) or CRISPR-Cas9 genome editing, and usage of microRNA (miRNA)-mediated regulation of gene expression led to the selection of many novel targets for new therapeutic development and the creation of promising combination therapies. This review explores the current state of advanced bioinformatics analysis and genetic technologies and their utilization for synergistic combination with TMZ in the context of inhibition of autophagy for controlling the growth of GBM.

Arsenite-induced cytotoxicity is regulated by poly-ADP ribose polymerase 1 activation and parthanatos in p53-deficient H1299 cells: The roles of autophagy and p53

Arsenic is a double-edged sword metalloid since it is both an environmental carcinogen and a chemopreventive agent. Arsenic cytotoxicity can be dependent or independent of the tumor suppressor p53. However, the effects and the underlying molecular mechanisms of arsenic cytotoxicity in p53-deficient cells are still unclear. Here, we report a distinctive cell death mode via PARP-1 activation by arsenic in p53-deficient H1299 cells. H1299 (p53^-/-) cells showed higher sensitivity to sodium arsenite (NaAR) than H460 (p53^+/+) cells. H460 cells induced canonical apoptosis through caspase-dependent poly-ADP ribose polymerase 1 (PARP-1) cleavage and induced the expression of phospho-p53 and p21. However, H1299 cells induced poly-ADP-ribose (PAR) polymer accumulation and caspase-independent parthanatos, which was inhibited by 3-aminobenzamide (AB) and nicotinamide (NAM). Fractionation studies revealed the mitochondrial translocation of PAR polymers and nuclear translocation of the apoptosis-inducing factor (AIF). Although the exposure of NaAR to p53-overexpressing H1299 cells increased the PAR polymer levels, it inhibited parthanatos by inducing p21 and phospho-p53 expression. LC3-II and p62 accumulated in a NaAR dose- and exposure time-dependent manner, and this accumulation was further enhanced by autophagy inhibition, indicating that arsenic inhibits autophagic flux. p53 overexpression led to a decrease in the p62 levels, an increase in the LC3-II levels, and reduced parthanatos, indicating that arsenic induces p53-dependent functional autophagy. These results show that the NaAR-induced cytotoxicity in p53-deficient H1299 cells is regulated by PARP-1 activation-mediated parthanatos, which is promoted by autophagy inhibition. This suggests that PARP-1 activation could be used as an effective therapeutic approach for arsenic toxicity in p53-deficient cells.

Is Autophagy Inhibition in Combination with Temozolomide a Therapeutically Viable Strategy?

Temozolomide is an oral alkylating agent that is used as the first line treatment for glioblastoma multiform, and in recurrent anaplastic astrocytoma, as well as having demonstrable activity in patients with metastatic melanoma. However, as the case with other chemotherapeutic agents, the development of resistance often limits the therapeutic benefit of temozolomide, particularly in the case of glioblastoma. A number of resistance mechanisms have been proposed including the development of cytoprotective autophagy. Cytoprotective autophagy is a survival mechanism that confers upon tumor cells the ability to survive in a nutrient deficient environment as well as under external stresses, such as cancer chemotherapeutic drugs and radiation, in part through the suppression of apoptotic cell death. In this review/commentary, we explore the available literature and provide an overview of the evidence for the promotion of protective autophagy in response to temozolomide, highlighting the possibility of targeting autophagy as an adjuvant therapy to potentially increase the effectiveness of temozolomide and to overcome the development of resistance.

Piperine attenuates the inflammation, oxidative stress, and pyroptosis to facilitate recovery from spinal cord injury via autophagy enhancement

Spinal cord injury (SCI) is a serious injury that can lead to irreversible motor dysfunction. Due to its complicated pathogenic mechanism, there are no effective drug treatments. Piperine, a natural active alkaloid extracted from black pepper, has been reported to influence neurogenesis and exert a neuroprotective effect in traumatic brain injury. The aim of this study was to investigate the therapeutic effect of piperine in an SCI model. SCI was induced in mice by clamping the spinal cord with a vascular clip for 1 min. Before SCI and every 2 days post-SCI, evaluations using the Basso mouse scale and inclined plane tests were performed. On day 28 after SCI, footprint analyses, and HE/Masson staining of tissues were performed. On a postoperative Day 3, the spinal cord was harvested to assess the levels of pyroptosis, reactive oxygen species (ROS), inflammation, and autophagy. Piperine enhanced functional recovery after SCI. Additionally, piperine reduced inflammation, oxidative stress, pyroptosis, and activated autophagy. However, the effects of piperine on functional recovery after SCI were reversed by autophagy inhibition. The study demonstrated that piperine facilitated functional recovery after SCI by inhibiting inflammatory, oxidative stress, and pyroptosis, mediated by the activation of autophagy.

Ciclopirox Olamine Induces Proliferation Inhibition and Protective Autophagy in Hepatocellular Carcinoma

Hepatocellular carcinoma is one of the most common fatal malignancies worldwide. Thus far, the hepatocellular carcinoma prognosis has been bleak due to deficiencies in the identification and diagnosis of early hepatocellular carcinoma. Ciclopirox olamine (CPX) is a synthetic antifungal agent and has been considered as an anti-cancer candidate drug recently, though the detailed mechanisms related to its anti-cancer effect in hepatocellular carcinoma have not yet been revealed. Here, we found that CPX could inhibit proliferation in HCC cells but not in intrahepatic cholangiocarcinoma cells by arresting the cell cycle. Moreover, the anti-cancer effects of CPX in HCC cells were also attributed to CPX-triggered ROS accumulation and DJ-1 downregulation. Additionally, CPX could promote complete autophagic flux, which alleviated the anti-cancer effect of CPX in HCC cells, whereas the ROS scavenger (NAC) would attenuate CPX-induced protective autophagy. Interestingly, CPX could also induce glycogen clustering in HCC cells. Altogether, this study provides a new insight into the detailed molecular mechanisms of CPX as an anti-cancer therapy and a strategy for treating hepatocellular carcinoma.

Hypoxia-Induced Autophagy Is Involved in Radioresistance via HIF1A-Associated Beclin-1 in Glioblastoma Multiforme

Radioresistance is the major factor of glioblastoma multiforme (GBM) treatment failure and relapse. Hypoxia and autophagy are linked to radioresistance and poor prognosis in solid tumors, but mechanisms remain unknown. Thus, we hypothesize that hypoxia may activate autophagy through two critical factors, HIF1A and Beclin-1, resulting in radioresistance of GBM in vitro and in vivo. In this study, we first demonstrated that HIF1A was overexpressed in GBM tissues and predicted a poor prognosis via bioinformatics. Secondly, we determined that hypoxia induced high expression of HIF1A and upregulated levels of Beclin-1 and autophagy, while HIF1A knockdown by shRNA reduced the expression of Beclin-1. Then we revealed the crosstalk and mechanisms of HIF1A-associated-Beclin-1 in three aspects: (a) transcriptional regulation, (b) protein interaction, and (c) HIF1A/BNIP3/Beclin-1 signaling pathway. Furthermore, we confirmed that silencing HIF1A enhanced the radiosensitivity of GBM in vitro and in vivo. Additionally, Beclin-1 suppression by 3-MA could reverse radioresistance induced by HIF1A under hypoxia. In conclusion, we demonstrated that hypoxia triggered autophagy via HIF1A-associated Beclin-1, resulting in radioresistance in GBM. HIF1A knockdown improved GBM radiosensitivity, and silencing Beclin-1 could reverse HIF1A-induced radioresistance under hypoxic conditions. These findings may help us comprehend the molecular underpinnings of hypoxia-induced autophagy and provide a novel perspective and prospective treatment for GBM radiosensitization.

Genetic markers associated with resistance to radioiodine therapy in thyroid cancer patients: Prospective cohort study

Background. The indication for radiotherapy in oncological practice are metastases of differentiated thyroid cancer after thyroidectomy, the presence of distant metastases, or stage N1b, or negative dynamics of blood thyroglobulin levels after thyroidectomy for thyroid cancer. The mechanism of action of radiotherapy is based on provoking double-stranded DNA breaks. It is important to study the role of polymorphisms of NFKB1, ATM, ATG16L2 and ATG10 genes, products of which are involved in the processes of DNA damage response pathway and autophagy, in the formation of resistance to radioiodine therapy of thyroid cancer patients. Aim. To examine the association between NFKB1, ATM, ATG16L2 and ATG10 polymorphisms and resistance to radioiodine therapy in thyroid cancer patients. Materials and methods. The study included 181 patients (37 men, 144 women; mean age 53.515.7 years) with histologically confirmed thyroid cancer and a history of thyroidectomy who received radioiodine therapy. Carriage of single-nucleotide polymorphisms (rs230493) NFKB1, (rs11212570) ATM, (rs10898880) ATG16L2 and (rs10514231, rs1864183, rs4703533) ATG10 was determined by real-time PCR using TaqMan kits. Results. Among 181 patients, resistance to radioiodine therapy was observed in 11 (6.1%) cases. No significant associations between the individual polymorphisms and resistance to radioiodine therapy were obtained, p0.05. Haplotype analysis showed that carriage of the C-C ATG10 rs10514231-rs1864183 haplotype was associated with an increased risk of developing resistance to radioiodine therapy, p=0.04. Conclusion. Further studies on large samples of radioiodine therapy-resistant patients using whole-genome sequencing methods are required to specify the role of genetic factors in the response to 131I therapy.

The effect of HIF-1α inhibition in breast cancer cells prior to doxorubicin treatment under conditions of normoxia and hypoxia

BACKGROUND

Oxygen deprivation is a key hallmark within solid tumours that contributes to breast-tumour pathophysiology. Under these conditions, neoplastic cells activate several genes, regulated by the HIF-1 transcription factor, which alters the tumour microenvironment to promote survival - including resistance to cell death in therapeutic attempts such as doxorubicin (Dox) treatment.

METHODS

We investigated HIF-1ɑ as a therapeutic target to sensitize breast cancer cells to Dox treatment. Under both normoxic (21% O₂) and hypoxic (∼0.1% O₂) conditions, the HIF-1 inhibitor, 2-methoxyestradiol (2-ME), was investigated as an adjuvant for its ability to alter MCF-7 cell viability, apoptosis, autophagy and molecular pathways which are often associated with increased cell survival.

RESULTS

Here we observed that an inverse relationship between HIF-1ɑ and apoptosis exists and that Dox promotes autophagy under hypoxic conditions. Although adjuvant therapy with 2-ME induced an antagonistic effect in breast cancer cells, upregulated HIF-1ɑ expression in a hypoxic environment promotes treatment resistance and this was attenuated once HIF-1ɑ gene expression was silenced.

CONCLUSION

Therefore, highlighting the identification of possible hypoxia-targeting therapies for breast cancer patients can be beneficial by promoting more favourable treatment responses.

Apoptosis and autophagy markers predict survival in neoadjuvant treated oesophageal adenocarcinoma patients

Background

Less than 20 % of patients with resectable oesophageal adenocarcinoma obtain a pathological response following neoadjuvant chemotherapy. Studies using oesophageal cancer cell lines have shown that drug sensitive tumour cells undergo apoptosis in response to drug treatment, whereas resistant cells induce autophagy and can recover following withdrawal of drug. In this study, we evaluated markers of apoptosis (active/cleaved caspase-3) and autophagy (LC3B) to establish whether these markers are useful prognostic indicators following neoadjuvant therapy.

Methods

Oesophageal adenocarcinoma tumour tissue from the Northern Ireland Biobank at Queens University Belfast was examined retrospectively. Tumours from 144 patients treated with platinum-based neoadjuvant chemotherapy followed by surgical resection were assembled into tissue microarrays prior to immunohistochemical analysis. Kaplan-Meier survival curves and log-rank tests were used to assess the impact of cleaved caspase-3 and LC3B expression on survival. Cox regression was used to examine association with clinical risk factors.

Results

High levels of cleaved caspase-3 were found in 14.6 % of patients and this correlated with a significantly better overall survival (p = 0.03). 38.9 % of patients had high cytoplasmic LC3B expression, which correlated with poor overall survival (p = 0.041). In addition, a distinct globular pattern of LC3B expression was identified in 40.3 % of patients and was also predictive of overall survival (p < 0.001). LC3B globular structures are also associated with tumour recurrence (p = 0.014).

When these markers were assessed in combination, it was found that patients who showed low/negative cleaved caspase-3 staining and high/positive staining for both patterns of LC3B had the worst overall survival (p < 0.001). Multi-variate analysis also indicated that this marker combination was an independent predictor of poor prognosis (p = 0.008; HR = 0.046, 95% CI = (0.005-0.443).

Conclusions

The expression of cleaved caspase-3 and specific LC3B staining patterns are associated with overall survival following neoadjuvant treatment. The combination of these markers is an independent indicator of outcome in neoadjuvant chemotherapy treated oesophageal adenocarcinoma.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09981-8.

Matrine induces autophagy in human neuroblastoma cells via blocking the AKT-mTOR pathway

Neuroblastoma (NB) is one of the most common malignant solid tumors in children. Despite significant advances in the treatment strategy, the long-term survival rate of NB patients is only 50%. Developing new agents for NB patients deserves attention. Recent research indicates that matrine, a natural quinolizidine alkaloid component extracted from the traditional Chinese medicine Sophora root, is widely used for various diseases, including antitumor effects against a variety of cancers. However, the effect of matrine on NB is unknown. Herein, we found that matrine exerted antiproliferative activity in human NB cells in dose- and time-dependent manner. Matrine triggered autophagy in NB cells by blocking the AKT-mTOR signaling pathway and suppressing the phosphorylation of AKT and mTOR. 3-Methyladenine (3-MA), a PI3K inhibitor, protected against matrine-induced inhibition of cell proliferation, further supporting that the antitumor activity of matrine was at least partly autophagy-dependent. In vivo, matrine reduced tumor growth of SK-N-DZ cells in a dose-dependent manner. Matrine treatment significantly declined the phosphorylation of AKT and mTOR and enhanced the LC3 II/GAPDH ratio in NB xenografts. Altogether, our work uncovered the molecular mechanism underlying matrine-induced autophagy in NB and provided implications for matrine as a potential therapeutic agent against NB.

Autophagic and apoptotic cell death induced by the quinoline derivative 2-(6-methoxynaphthalen-2-yl)quinolin-4-amine in pancreatic cancer cells is via ER stress and inhibition of Akt/mTOR signaling pathway

Pancreatic cancer (PC) is among the most lethal cancers and is resistant to existing therapies, which highlights the need for new and alternative therapeutic treatments. Autophagy is emerging as one of the alternative cell death mechanisms and is well known to cross-talk with apoptosis. Autophagy can act as a viable option to treat highly resistant PC. The current study investigates and provides insight into the autophagic and apoptotic cell death induced by quinoline derivative 2-(6-methoxynaphthalen-2-yl)quinolin-4-amine (6MN-4-AQ) in PC cell lines PANC-1 and MIA PaCa-2. Treatment with 6MN-4-AQ reduced cell viability in concentration dependent manner (2-16 μM) and inhibited the clonogenic potential of PC cells at a concentration of 4 μM for 24 h. Further, we found that 6MN-4-AQ induced both apoptosis and autophagic cell death simultaneously. We identified that 6MN-4-AQ induced autophagic cell death by forming cytoplasmic vacuoles, the elevation of autophagy flux, increase in LC3-II, Beclin-1 protein expression, and degradation of p62. Moreover, 6MN-4-AQ induced apoptosis via Caspase-3 activation and cleavage of PARP in PC cells. Upon investigating the underlying mechanism associated with 6MN-4-AQ induced cell death, it was observed that 6MN-4-AQ treatment is able to suppress the Akt/mTOR pathway and induced ER stress leading to the induction of autophagy. Also, 6MN-4-AQ treatment suppressed epithelial to mesenchymal transition by reducing the protein expression of SLUG, snail, and vimentin. Subsequently, 6MN-4-AQ inhibited cell migration and invasion by down regulating MMP-7 and MMP-9 protein expression, suggesting that 6MN-4-AQ may serve as a plausible therapeutic agent for PC.

Passiflora mollissima Seed Extract Induced Antiproliferative and Cytotoxic Effects on CAL 27 Spheroids

Multicellular tumor spheroids are used as models in drug development due to their characteristics simulating in vivo tumors. Likewise, antiproliferative properties of extracts derived from fruits have been widely described. Peels and seeds can be used as a matrix to obtain different compounds. Recently, a study demonstrated the antiproliferative activity from a P. mollissima extract (PME) on human colon cancer cells; however, its effect on oral spheroids is unknown. Objective. To evaluate the antiproliferative potential of an extract obtained from P. mollissima seeds on the spheroid-type-3D culture model of CAL 27. Methods. CAL 27-spheroids were treated with three concentrations of PME (10, 50, and 100 μg/ml). After 72 hr incubation, morphology and cellular changes, cytotoxic and proapoptotic effect, gene expression, and metastasis were determined. Additionally, changes in the cell cycle phases responded to the PME concentrations. Comparisons between groups were made through a U Mann-Whitney test. Results. It was shown that 100 μg/ml PE affects CAL 27 cells proliferation grown in spheroids through cell cycle arrest and gene regulation of p53, HIF 1α, and CDH1. However, none of the treatments employed induced MMP9 gene expression. Conclusion. Our study shows that PME inhibits the growth and proliferation of oral tumor cells cultured in spheroids through the positive regulation of cell death and metastasis genes.

JCI-20679 suppresses autophagy and enhances temozolomide-mediated growth inhibition of glioblastoma cells

Glioblastoma, a type of brain cancer, is one of the most aggressive and lethal types of malignancy. The present study shows that JCI-20679, an originally synthesized mitochondrial complex I inhibitor, enhances the anti-proliferative effects of suboptimal concentrations of the clinically used chemotherapeutic drug temozolomide in glioblastoma cells. Analysis of the effects of temozolomide combined with JCI-20679 using isobologram and combination index methods demonstrated that the combination had synergistic effects in murine and human glioblastoma cells. We found that JCI-20679 inhibited the temozolomide-mediated induction of autophagy that facilitates cellular survival. The autophagy induced by temozolomide increased ATP production, which confers temozolomide resistance in glioblastoma cells. JCI-20679 blocked temozolomide-mediated increases in ATP levels and increased the AMP/ATP ratio. Furthermore, JCI-20679 enhanced the therapeutic effects of temozolomide in an orthotopic transplantation model of glioblastoma. These results indicate that JCI-20679 may be promising as a novel agent for enhancing the efficacy of temozolomide against glioblastoma.

Enabling high throughput drug discovery in 3D cell cultures through a novel bioprinting workflow

Advanced three dimensional cell culture techniques have been adopted in many laboratories to better model in vivo tissue by recapitulating multi-cellular architecture and the presence of extracellular matrix features. We describe here a 3D cell culture platform in a small molecule screening workflow that uses traditional biomarker and intracellular kinase end point assay readouts. By combining the high throughput bioprinter RASTRUM with the high throughput screening assay AlphaLISA, we demonstrate the utility of the protocol in 3D synthetic hydrogel cultures with breast cancer (MDA-MB-231 and MCF-7) and fibroblast cells. To establish and validate the workflow, we treated the breast cancer cultures with doxorubicin, while fibroblast cultures were stimulated with the pro-inflammatory lipopolysaccharide. 3D and 2D MDA-MB-231 cultures were equally susceptible to doxorubicin treatment, while showing opposite ERK phosphorylation changes. Doxorubicin readily entered embedded MCF-7 spheroids and markedly reduced intracellular GSK3β phosphorylation. Furthermore, quantifying extracellular interleukin 6 levels showed a very similar activation profile for fibroblasts in 2D and 3D cultures, with 3D fibroblast networks being more resistant against the immune challenge. Through these validation experiments we demonstrate the full compatibility of the bioprinted 3D cell cultures with several widely-used 2D culture assays. The efficiency of the workflow, minimal culture handling, and applicability of traditional screening assays, demonstrates that advanced encapsulated 3D cell cultures can be used in 2D cell culture screening workflows, while providing a more holistic view on cell biology to increase the predictability to in vivo drug response.

The complex interplay between autophagy and cell death pathways

Autophagy is a universal cellular homeostatic process, required for the clearance of dysfunctional macromolecules or organelles. This self-digestion mechanism modulates cell survival, either directly by targeting cell death players, or indirectly by maintaining cellular balance and bioenergetics. Nevertheless, under acute or accumulated stress, autophagy can also contribute to promote different modes of cell death, either through highly regulated signalling events, or in a more uncontrolled inflammatory manner. Conversely, apoptotic or necroptotic factors have also been implicated in the regulation of autophagy, while specific factors regulate both processes. Here, we survey both earlier and recent findings, highlighting the intricate interaction of autophagic and cell death pathways. We, Furthermore, discuss paradigms, where this cross-talk is disrupted, in the context of disease.

Dysregulated Autophagy and Mitophagy in a Mouse Model of Duchenne Muscular Dystrophy Remain Unchanged Following Heme Oxygenase-1 Knockout

Dysregulation of autophagy may contribute to the progression of various muscle diseases, including Duchenne muscular dystrophy (DMD). Heme oxygenase-1 (HO-1, encoded by Hmox1), a heme-degrading enzyme, may alleviate symptoms of DMD, inter alia, through anti-inflammatory properties. In the present study, we determined the role of HO-1 in the regulation of autophagy and mitophagy in mdx animals, a commonly used mouse model of the disease. In the gastrocnemius of 6-week-old DMD mice, the mRNA level of mitophagy markers: Bnip3 and Pink1, as well as autophagy regulators, e.g., Becn1, Map1lc3b, Sqstm1, and Atg7, was decreased. In the dystrophic diaphragm, changes in the latter were less prominent. In older, 12-week-old dystrophic mice, diminished expressions of Pink1 and Sqstm1 with upregulation of Atg5, Atg7, and Lamp1 was depicted. Interestingly, we demonstrated higher protein levels of autophagy regulator, LC3, in dystrophic muscles. Although the lack of Hmox1 in mdx mice influenced blood cell count and the abundance of profibrotic proteins, no striking differences in mRNA and protein levels of autophagy and mitophagy markers were found. In conclusion, we demonstrated complex, tissue, and age-dependent dysregulation of mitophagic and autophagic markers in DMD mice, which are not affected by the additional lack of Hmox1.

Regulation of autophagy as a therapeutic option in glioblastoma

Around three out of one hundred thousand people are diagnosed with glioblastoma multiforme, simply called glioblastoma, which is the most common primary brain tumor in adults. With a dismal prognosis of a little over a year, receiving a glioblastoma diagnosis is oftentimes fatal. A major advancement in its treatment was made almost two decades ago when the alkylating chemotherapeutic agent temozolomide (TMZ) was combined with radiotherapy (RT). Little progress has been made since then. Therapies that focus on the modulation of autophagy, a key process that regulates cellular homeostasis, have been developed to curb the progression of glioblastoma. The dual role of autophagy (cell survival or cell death) in glioblastoma has led to the development of autophagy inhibitors and promoters that either work as monotherapies or as part of a combination therapy to induce cell death, cellular senescence, and counteract the ability of glioblastoma stem cells (GSCs) for initiating tumor recurrence. The myriad of cellular pathways that act upon the modulation of autophagy have created contention between two groups: those who use autophagy inhibition versus those who use promotion of autophagy to control glioblastoma growth. We discuss rationale for using current major therapeutics, their molecular mechanisms for modulation of autophagy in glioblastoma and GSCs, their potentials for making strides in combating glioblastoma progression, and their possible shortcomings. These shortcomings may fuel the innovation of novel delivery systems and therapies involving TMZ in conjunction with another agent to pave the way towards a new gold standard of glioblastoma treatment.

Breaking Bad: Autophagy Tweaks the Interplay Between Glioma and the Tumor Immune Microenvironment

Though significant strides in tumorigenic comprehension and therapy modality have been witnessed over the past decades, glioma remains one of the most common and malignant brain tumors characterized by recurrence, dismal prognosis, and therapy resistance. Immunotherapy advance holds promise in glioma recently. However, the efficacy of immunotherapy varies among individuals with glioma, which drives researchers to consider the modest levels of immunity in the central nervous system, as well as the immunosuppressive tumor immune microenvironment (TIME). Considering the highly conserved property for sustaining energy homeostasis in mammalian cells and repeatedly reported links in malignancy and drug resistance, autophagy is determined as a cutting angle to elucidate the relations between glioma and the TIME. In this review, heterogeneity of TIME in glioma is outlined along with the reciprocal impacts between them. In addition, controversies on whether autophagy behaves cytoprotectively or cytotoxically in cancers are covered. How autophagy collapses from its homeostasis and aids glioma malignancy, which may depend on the cell type and the cellular context such as reactive oxygen species (ROS) and adenosine triphosphate (ATP) level, are briefly discussed. The consecutive application of autophagy inducers and inhibitors may improve the drug resistance in glioma after overtreatments. It also highlights that autophagy plays a pivotal part in modulating glioma and the TIME, respectively, and the intricate interactions among them. Specifically, autophagy is manipulated by either glioma or tumor-associated macrophages to conform one side to the other through exosomal microRNAs and thereby adjust the interactions. Given that some of the crosstalk between glioma and the TIME highly depend on the autophagy process or autophagic components, there are interconnections influenced by the status and well-being of cells presumably associated with autophagic flux. By updating the most recent knowledge concerning glioma and the TIME from an autophagic perspective enhances comprehension and inspires more applicable and effective strategies targeting TIME while harnessing autophagy collaboratively against cancer.

Casein Kinase-1-Alpha Inhibitor (D4476) Sensitizes Microsatellite Instable Colorectal Cancer Cells to 5-Fluorouracil via Authophagy Flux Inhibition

Adjuvant chemotherapy with 5-fluorouracil (5-FU) does not improve survival of patients suffering from a form of colorectal cancer (CRC) characterized by high level of microsatellite instability (MSI-H). Given the importance of autophagy and multi-drug-resistant (MDR) proteins in chemotherapy resistance, as well as the role of casein kinase 1-alpha (CK1α) in the regulation of autophagy, we tested the combined effect of 5-FU and CK1α inhibitor (D4476) on HCT116 cells as a model of MSI-H colorectal cancer. To achieve this goal, the gene expression of Beclin1 and MDR genes, ABCG2 and ABCC3 were analyzed using quantitative real-time polymerase chain reaction. We used immunoblotting to measure autophagy flux (LC3, p62) and flow cytometry to detect apoptosis. Our findings showed that combination treatment with 5-FU and D4476 inhibited autophagy flux. Moreover, 5-FU and D4476 combination therapy induced G2, S and G1 phase arrests and it depleted mRNA of both cell proliferation-related genes and MDR-related genes (ABCG2, cyclin D1 and c-myc). Hence, our data indicates that targeting of CK1α may increase the sensitivity of HCT116 cells to 5-FU. To our knowledge, this is the first description of sensitization of CRC cells to 5-FU chemotherapy by CK1α inhibitor.

Suppressed PLIN3 frequently occurs in prostate cancer, promoting docetaxel resistance via intensified autophagy, an event reversed by chloroquine

Lipid metabolism reprogramming is one of the adaptive events that drive tumor development and survival, and may account for resistance to chemotherapeutic drugs. Perilipins are structural proteins associated with lipophagy and lipid droplet integrity, and their overexpression is associated with tumor aggressiveness. Here, we sought to explore the role of lipid droplet-related protein perilipin-3 (PLIN3) in prostate cancer (PCa) chemotherapy. We investigated the role of PLIN3 suppression in docetaxel cytotoxic activity in PCa cell lines. Additional effects of PLIN3 depletion on autophagy-related proteins and gene expression patterns, apoptotic potential, proliferation rate, and ATP levels were examined. Depletion of PLIN3 resulted in docetaxel resistance, accompanied by enhanced autophagic flux. We further assessed the synergistic effect of autophagy suppression with chloroquine on docetaxel cytotoxicity. Inhibition of autophagy with chloroquine reversed chemoresistance of stably transfected shPLIN3 PCa cell lines, with no effect on the parental ones. The shPLIN3 cell lines also exhibited reduced Caspase-9 related apoptosis initiation. Moreover, we assessed PLIN3 expression in a series of PCa tissue specimens, were complete or partial loss of PLIN3 expression was frequently noted in 70% of the evaluated specimens. Following PLIN3 silencing, PCa cells were characterized by impaired lipophagy and acquired an enhanced autophagic response upon docetaxel-induced cytotoxic stress. Such an adaptation leads to resistance to docetaxel, which could be reversed by the autophagy blocker chloroquine. Given the frequent loss of PLIN3 expression in PCa specimens, we suggest that combination of docetaxel with chloroquine may improve the efficacy of docetaxel treatment in PLIN3-deficient cancer patients.

The Role of the Ubiquitin Proteasome System in Glioma: Analysis Emphasizing the Main Molecular Players and Therapeutic Strategies Identified in Glioblastoma Multiforme

Gliomas constitute the most frequent tumors of the brain. High-grade gliomas are characterized by a poor prognosis caused by a set of attributes making treatment difficult, such as heterogeneity and cell infiltration. Additionally, there is a subgroup of glioma cells with properties similar to those of stem cells responsible for tumor recurrence after treatment. Since proteasomal degradation regulates multiple cellular processes, any mutation causing disturbances in the function or expression of its elements can lead to various disorders such as cancer. Several studies have focused on protein degradation modulation as a mechanism of glioma control. The ubiquitin proteasome system is the main mechanism of cellular proteolysis that regulates different events, intervening in pathological processes with exacerbating or suppressive effects on diseases. This review analyzes the role of proteasomal degradation in gliomas, emphasizing the elements of this system that modulate different cellular mechanisms in tumors and discussing the potential of distinct compounds controlling brain tumorigenesis through the proteasomal pathway.

The Sex-Related Interplay between TME and Cancer: On the Critical Role of Estrogen, MicroRNAs and Autophagy

The interplay between cancer cells and the tumor microenvironment (TME) has a fundamental role in tumor progression and response to therapy. The plethora of components constituting the TME, such as stroma, fibroblasts, endothelial and immune cells, as well as macromolecules, e.g., hormones and cytokines, and epigenetic factors, such as microRNAs, can modulate the survival or death of cancer cells. Actually, the TME can stimulate the genetically regulated programs that the cell puts in place under stress: apoptosis or, of interest here, autophagy. However, the implication of autophagy in tumor growth appears still undefined. Autophagy mainly represents a cyto-protective mechanism that allows cell survival but, in certain circumstances, also leads to the blocking of cell cycle progression, possibly leading to cell death. Since significant sex/gender differences in the incidence, progression and response to cancer therapy have been widely described in the literature, in this review, we analyzed the roles played by key components of the TME, e.g., estrogen and microRNAs, on autophagy regulation from a sex/gender-based perspective. We focused our attention on four paradigmatic and different forms of cancers-colon cancer, melanoma, lymphoma, and lung cancer-concluding that sex-specific differences may exert a significant impact on TME/cancer interaction and, thus, tumor growth.

EGCG synergizes the therapeutic effect of irinotecan through enhanced DNA damage in human colorectal cancer cells

Irinotecan is a kind of alkaloid with antitumour activity, but its low solubility and high toxicity limit its application. Epigallocatechin‐3‐gallate (EGCG) is one of the main bioactive components in tea. The epidemiological investigation and animal and cell experiments show that EGCG has a preventive and therapeutic effect on many kinds of tumours. Here, colorectal cancer cells RKO and HCT116 were employed, and the CCK8 proliferation test was used to screen the appropriate concentration of EGCG and irinotecan, and the effects of single and/or combined drugs on migration, invasion, DNA damage, cell cycle and autophagy of tumour cells were investigated. The results showed that EGCG combined with irinotecan (0.5 μmol L⁻) not only had a stronger inhibitory effect on tumour cells than EGCG or irinotecan alone but also prevented tumour cell migration and invasion. EGCG alone did not cause DNA damage in colorectal cancer cells, but its combination with irinotecan could induce S or G2 phase arrest by inhibiting topoisomerase I to cause more extensive DNA damage. EGCG also induced apoptosis by promoting autophagy with irinotecan synergistically. These results indicated that EGCG in combination with irinotecan could be a promising strategy for colorectal cancer.

Dual Characters of GH-IGF1 Signaling Pathways in Radiotherapy and Post-radiotherapy Repair of Cancers

Radiotherapy remains one of the most important cancer treatment modalities. In the course of radiotherapy for tumor treatment, the incidental irradiation of adjacent tissues could not be completely avoided. DNA damage is one of the main factors of cell death caused by ionizing radiation, including single-strand (SSBs) and double-strand breaks (DSBs). The growth hormone-Insulin-like growth factor 1 (GH-IGF1) axis plays numerous roles in various systems by promoting cell proliferation and inhibiting apoptosis, supporting its effects in inducing the development of multiple cancers. Meanwhile, the GH-IGF1 signaling involved in DNA damage response (DDR) and DNA damage repair determines the radio-resistance of cancer cells subjected to radiotherapy and repair of adjacent tissues damaged by radiotherapy. In the present review, we firstly summarized the studies on GH-IGF1 signaling in the development of cancers. Then we discussed the adverse effect of GH-IGF1 signaling in radiotherapy to cancer cells and the favorable impact of GH-IGF1 signaling on radiation damage repair to adjacent tissues after irradiation. This review further summarized recent advances on research into the molecular mechanism of GH-IGF1 signaling pathway in these effects, expecting to specify the dual characters of GH-IGF1 signaling pathways in radiotherapy and post-radiotherapy repair of cancers, subsequently providing theoretical basis of their roles in increasing radiation sensitivity during cancer radiotherapy and repairing damage after radiotherapy.

Radiation-Induced Autophagy in Human Pancreatic Cancer Cells is Critically Dependent on G2 Checkpoint Activation: A Mechanism of Radioresistance in Pancreatic Cancer

PURPOSE

Autophagy and cell-cycle checkpoints act in concert to confer cellular radioresistance. We investigated the functional interaction between radiation-induced autophagy and G2 checkpoint activation in highly radioresistant human pancreatic ductal adenocarcinoma (PDAC) cells.

METHODS AND MATERIALS

Four human PDAC cell lines (MIA PaCa-2, KP-4, Panc-1, and SUIT-2) were analyzed. These cells were first irradiated using x-rays, and their cell cycle status, autophagy, and cell cycle checkpoint marker expression and ATP production levels were evaluated. Autophagic flux assays and siRNA knockdown were used to evaluate autophagy activity. Double thymidine block experiments were performed to synchronize the cells. Two inhibitors (MK-1775 and SCH 900776) were used to attenuate G2 checkpoint activation. Cell survival assays and animal experiments were performed to evaluate the radiosensitizing effects of the G2 checkpoint inhibitors.

RESULTS

Autophagy and G2/M accumulation were synchronously induced in human PDAC cells with an activated G2 checkpoint at 12 hours after x-ray irradiation of 6 Gy. Radiation-induced autophagy produced the ATP levels required for cell survival. Double thymidine block experiments revealed that no autophagy occurred in cells that were solely in G2 phase. MK-1775 or SCH 900776 exposure attenuated not only G2 checkpoint activation but also postirradiation autophagy, indicating the dependence of radiation-induced autophagy on an activated G2 checkpoint. The inhibitors demonstrated a higher radiosensitizing effect in the PDAC cells than the autophagy inhibitor chloroquine. MK-1775 in combination with x-rays significantly suppressed the tumor growth of MIA PaCa-2 xenografts compared with other treatment groups, including radiation or drug exposure alone, to enhance the radiosensitivity of PDAC cells in vivo.

CONCLUSIONS

Biological crosstalk exists between the G2 checkpoint activation and radiation-induced autophagy processes that are believed to independently contribute to the radioresistance of human PDAC cells. These findings have important implications for the development of future radiation therapy strategies for PDAC.

Autophagy inhibitor potentiates the antitumor efficacy of apatinib in uterine sarcoma by stimulating PI3K/Akt/mTOR pathway

AIM

The present study aims to examine the effects of apatinib combined with autophagy inhibitor 3-Methyladenine (3-MA) on the proliferation and apoptosis of human uterine sarcoma in FU-MMT-1 and MES-SA cells and its tumor inhibition effect in xenograft model of uterine sarcoma.

METHODS

Different concentrations of 3-MA and apatinib were used to treat the uterine sarcoma cell lines (MES-SA and FU-MMT-1 cells). The cell viability was detected by CCK8 method. Flow cytometry was used to detect the apoptosis and cell cycle. Wound closure assay and Transwell assay were performed to measure the migration ability of cells. Western blot was used to determine the apoptosis proteins and autophagy proteins. A nude mice sarcoma xenograft model was established and treated with apatinib alone, 3-MA alone, or combined incubation of them. Tumor size of xenograft and the mice survival rate were measured.

RESULTS

Combination of 3-MA and apatinib significantly inhibited the proliferation and migration ability, but increased the apoptosis rate of uterine sarcoma cells compared to apatinib. The combination of 3-MA and apatinib significantly limited the tumor size of xenograft and increased the survival rate of mice compared to apatinib alone. Apatinib inhibited the PI3K/Akt/mTOR pathway, while 3-MA and the combination of 3-MA and apatinib significantly activated the PI3K/Akt/mTOR pathway and inhibited autophagy. Combination of 3-MA and apatinib increased apoptosis compared to apatinib alone. The expression of VEGFR-2 was not impacted by 3-MA.

CONCLUSION

Combination of apatinib and autophagy inhibitor 3-MA significantly inhibited the growth and migration of uterine sarcoma cells and xenograft. Autophagy inhibition may increase the antitumor effect of apatinib via the PI3K/Akt/mTOR pathway.

Chemotherapeutic drugs: Cell death- and resistance-related signaling pathways. Are they really as smart as the tumor cells?

Chemotherapeutic drugs kill cancer cells or control their progression all over the patient's body, while radiation- and surgery-based treatments perform in a particular site. Based on their mechanisms of action, they are classified into different groups, including alkylating substrates, antimetabolite agents, anti-tumor antibiotics, inhibitors of topoisomerase I and II, mitotic inhibitors, and finally, corticosteroids. Although chemotherapeutic drugs have brought about more life expectancy, two major and severe complications during chemotherapy are chemoresistance and tumor relapse. Therefore, we aimed to review the underlying intracellular signaling pathways involved in cell death and resistance in different chemotherapeutic drug families to clarify the shortcomings in the conventional single chemotherapy applications. Moreover, we have summarized the current combination chemotherapy applications, including numerous combined-, and encapsulated-combined-chemotherapeutic drugs. We further discussed the possibilities and applications of precision medicine, machine learning, next-generation sequencing (NGS), and whole-exome sequencing (WES) in promoting cancer immunotherapies. Finally, some of the recent clinical trials concerning the application of immunotherapies and combination chemotherapies were included as well, in order to provide a practical perspective toward the future of therapies in cancer cases.

α-Tomatine, a novel early-stage autophagy inhibitor, inhibits autophagy to enhance apoptosis via Beclin-1 in Skov3 cells

Targeting the autophagy process is considered to be a promising new strategy for drug treatment of ovarian cancer. α-Tomatine, a steroidal alkaloid extracted, is mainly isolated from leaves, roots and immature green tomatoes. α-Tomatine has biological activities such as anticancer, antioxidative and anti-inflammatory. The study aimed to explore the effects of α-tomatine on proliferation, apoptosis and autophagy and the underlying mechanisms in ovarian cancer Skov3 cells. After treatment with different concentrations of α-tomatine (0, 0.75, 1 and 1.5 μM) in Skov3 cells for 24 h, proliferation was determined by the CCK-8 assay, and apoptosis was detected by flow cytometric analysis. Autophagy in cells was determined by the number of fluorescent spots using confocal fluorescence microscopy after mRFP-GFP-LC3 transfection. The relationship between autophagy and apoptosis was proved by Beclin-1 overexpression. The protein expression levels were tested by western blotting. The results demonstrated that α-tomatine effectively repressed proliferation, exerted a proapoptotic effect and inhibited early-stage autophagy in Skov3 cells in a dose- and time-dependent manner. Additionally, Beclin-1 overexpression significantly suppressed α-tomatine-treated apoptosis in Skov3 cells, indicating that α-tomatine inhibits autophagy to induce apoptosis. We also found α-tomatine inhibited the protein expression levels of PI3K/Akt/mTOR signaling pathway. However, the autophagy inhibition of α-tomatine could be reversed obviously by Beclin-1 overexpression. Taken together, α-tomatine inhibited autophagy through Beclin-1. Our study suggests that α-tomatine, as a novel early-stage autophagy inhibitor, might be a potential drug for further treatment of ovarian cancer by inhibiting proliferation and promoting apoptosis.

Endonuclease G promotes autophagy by suppressing mTOR signaling and activating the DNA damage response

Endonuclease G (ENDOG), a mitochondrial nuclease, is known to participate in many cellular processes, including apoptosis and paternal mitochondrial elimination, while its role in autophagy remains unclear. Here, we report that ENDOG released from mitochondria promotes autophagy during starvation, which we find to be evolutionally conserved across species by performing experiments in human cell lines, mice, Drosophila and C. elegans. Under starvation, Glycogen synthase kinase 3 beta-mediated phosphorylation of ENDOG at Thr-128 and Ser-288 enhances its interaction with 14-3-3γ, which leads to the release of Tuberin (TSC2) and Phosphatidylinositol 3-kinase catalytic subunit type 3 (Vps34) from 14-3-3γ, followed by mTOR pathway suppression and autophagy initiation. Alternatively, ENDOG activates DNA damage response and triggers autophagy through its endonuclease activity. Our results demonstrate that ENDOG is a crucial regulator of autophagy, manifested by phosphorylation-mediated interaction with 14-3-3γ, and its endonuclease activity-mediated DNA damage response.

Autophagy and renal cell carcinoma: What do we know so far?

Renal cell carcinoma (RCC) is the most common type of kidney tumor in adults, accounting for approximately 90% of kidney malignances, occurring usually between the ages of 60 and 70. The 5-year overall survival rate for all RCC types is 49%. Since RCCs are resistant to numeorus different radio and chemotherapeutics that act via apoptosis induction, the development of new approaches to RCC treatment is still in the focus of modern urology. In particular, in recent years, autophagy in RCC has been widely studied as a mechanism of cell extinction through which tumor cells can overcome resistance to apoptosis activation therapy. Autophagy is often referred to as a double-edged sword because it can be a process that allows cells of cancer to survive and, on the other hand and under other conditions, it can be a cell dying mechanism, independent or closely related to other cell death modalities, like apoptosis and necrosis. The central role in the tempering of the process of autophagy, in general, belongs to the mTOR complex (mammalian target of rapamycin), which integrates numerous signals that affect autophagy, such as growth factors, nutrients, various stressors and the energy status of the cell. In RCC, the most important is PI3K/AKT/mTOR signaling pathway, since activation of this signaling leads to survival of tumor cells through mTOR activation and thus, autophagy inhibition. Up to now, it was found that autophagy markers such as Beclin-1 and LC3-II can be considered as prognostic markers for RCC since the high level of Beclin-1 was detected in tissues and cells of RCC (A498 and ACHN cell lines) and that tumor cell mobility is promoted by the up-regulated expression of LC3. Therefore, a progress in RCC therapy can be expected from the development and synthesis of specific compounds targeting autophagy, as well as the therapy based on their combination.

The Relationships Between Trait Creativity and Resting-State EEG Microstates Were Modulated by Self-Esteem

Numerous studies find that creativity is not only associated with low effort and flexible processes but also associated with high effort and persistent processes especially when defensive behavior is induced by negative emotions. The important role of self-esteem is to buffer negative emotions, and individuals with low self-esteem are prone to instigating various forms of defensive behaviors. Thus, we thought that the relationships between trait creativity and executive control brain networks might be modulated by self-esteem. The resting-state electroencephalogram (RS-EEG) microstates can be divided into four classical types (MS1, MS2, MS3, and MS4), which can reflect the brain networks as well as their dynamic characteristic. Thus, the Williams Creative Tendency Scale (WCTS) and Rosenberg Self-esteem Scale (RSES) were used to investigate the modulating role of self-esteem on the relationships between trait creativity and the RS-EEG microstates. As our results showed, self-esteem consistently modulated the relationships between creativity and the duration and contribution of MS2 related to visual or imagery processing, the occurrence of MS3 related to cingulo-opercular networks, and transitions between MS2 and MS4, which were related to frontoparietal control networks. Based on these results, we thought that trait creativity was related to the executive control of bottom-up processing for individuals with low self-esteem, while the bottom-up information from vision or visual imagery might be related to trait creativity for individuals with high self-esteem.