LAMP2A-mediated neuronal hyperexcitability by enhancing NKAβ1 degradation underlies depression-induced allodynia

Painful physical symptoms in major depressive disorder (MDD) patients lead to poor outcomes during MDD treatment. Here, we report that decreased Na+/K+-ATPase β1 subunit (NKAβ1) expression in anterior cingulate cortex glutamatergic (ACCGlu) neurons promotes ion dyshomeostasis, leading to hyperactivity of ACCGlu-insular cortex circuits in chronic stress mice. This ultimately primes allodynia. Mechanistically, we reveal that chronic stress strengthens LAMP2A-driven chaperone-mediated autophagy (CMA) and subsequently promotes the degradation of NKAβ1. We further identify NKAβ1 as a CMA substrate. Accordingly, genetically LAMP2A loss in ACCGlu neurons reverses chronic-stress-induced neuronal hyperexcitability, subsequently ameliorating allodynia. Additionally, we develop a trans-activating transcription (TAT)-LAMP2A peptide that significantly alleviates depression-induced allodynia. Taken together, our results reveal a mechanistic connection between CMA and neuronal excitability. TAT-LAMP2A peptide intervention, by disturbing CMA-dependent NKAβ1 elimination, could be a potential pharmacological treatment for depression-induced allodynia and further facilitate the efficacy of antidepressant treatment.

Research Advances in Chaperone-Mediated Autophagy (CMA) and CMA-Based Protein Degraders

Molecular mechanisms of chaperone-mediated autophagy (CMA) constitute essential regulatory elements in cellular homeostasis, encompassing protein quality control, metabolic regulation, cellular signaling cascades, and immunological functions. Perturbations in CMA functionality have been causally associated with various pathological conditions, including neurodegenerative pathologies and neoplastic diseases. Recent advances in targeted protein degradation (TPD) methodologies have demonstrated that engineered degraders incorporating KFERQ-like motifs can facilitate lysosomal translocation and subsequent proteolysis of noncanonical substrates, offering novel therapeutic interventions for both oncological and neurodegenerative disorders. This comprehensive review elucidates the molecular mechanisms, physiological significance, and pathological implications of CMA pathways. Additionally, it provides a critical analysis of contemporary developments in CMA-based degrader technologies, with particular emphasis on their structural determinants, mechanistic principles, and therapeutic applications. The discourse extends to current technical limitations in CMA investigation and identifies key obstacles that must be addressed to advance the development of CMA-targeting therapeutic agents.

Graphene-Based Photodynamic Therapy and Overcoming Cancer Resistance Mechanisms: A Comprehensive Review

Photodynamic therapy (PDT) is a non-invasive therapy that has made significant progress in treating different diseases, including cancer, by utilizing new nanotechnology products such as graphene and its derivatives. Graphene-based materials have large surface area and photothermal effects thereby making them suitable candidates for PDT or photo-active drug carriers. The remarkable photophysical properties of graphene derivates facilitate the efficient generation of reactive oxygen species (ROS) upon light irradiation, which destroys cancer cells. Surface functionalization of graphene and its materials can also enhance their biocompatibility and anticancer activity. The paper delves into the distinct roles played by graphene-based materials in PDT such as photosensitizers (PS) and drug carriers while at the same time considers how these materials could be used to circumvent cancer resistance. This will provide readers with an extensive discussion of various pathways contributing to PDT inefficiency. Consequently, this comprehensive review underscores the vital roles that graphene and its derivatives may play in emerging PDT strategies for cancer treatment and other medical purposes. With a better comprehension of the current state of research and the existing challenges, the integration of graphene-based materials in PDT holds great promise for developing targeted, effective, and personalized cancer treatments.

Recent advances of ferroptosis in tumor: From biological function to clinical application

Ferroptosis is a recently recognized form of cell death with distinct features in terms of morphology, biochemistry, and molecular mechanisms. Unlike other types of cell death, ferroptosis is characterized by iron dependence, reactive oxygen species accumulation and lipid peroxidation. Recent studies have demonstrated that selective autophagy plays a vital role in the induction of ferroptosis, including ferritinophagy, lipophagy, clockophagy, and chaperone-mediated autophagy. Emerging evidence has indicated the involvement of ferroptosis in tumorigenesis through regulating various biological processes, including tumor growth, metastasis, stemness, drug resistance, and recurrence. Clinical and preclinical studies have found that novel therapies targeting ferroptosis exert great potential in the treatment of tumors. This review provides a comprehensive overview of the molecular mechanisms in ferroptosis, especially in autophagy-driven ferroptosis, discusses the recent advances in the biological roles of ferroptosis in tumorigenesis, and highlights the application of novel ferroptosis-targeted therapies in the clinical treatment of tumors.

Chaperone-mediated autophagy degrade Dicer to promote breast cancer metastasis

Metastasis in breast cancer usually lead to the majority of deaths on clinical patients. Accordingly, diagnosis of metastasis at the early stage in breast cancer is important to improve the prognosis. We observed that Dicer protein levels are significant decrease in highly invasive breast cancer cells and usually correlated with poor clinical outcomes. Following, we aim to clarify the molecular regulatory mechanism of this phenomenon in breast cancer to provide a new therapeutic target. In this study, we obtained that Dicer expression correlated with metastasis and invasion without affect cell stability in breast cancer cells. Importantly, we identified the regulatory mechanism of Dicer protein degradation, the chaperone-mediated autophagy (CMA)-mediated degradation that is major mechanism to decrease Dicer protein expression and lead to cancer metastasis. We discovered that heat shock cognate 71-kDa protein (Hsc70) which as a CMA-related factor interacts with the CMA-targeting motif I333A/K334A on Dicer to promote degradation through CMA. Taken together, our findings hint that Dicer highly correlated with cancer metastasis, we reveal the tumor-promoting effect of CMA-mediated Dicer degradation in breast cancer.

Apoptosis, Proliferation, and Autophagy Are Involved in Local Anesthetic-Induced Cytotoxicity of Human Breast Cancer Cells

Breast cancer accounts for almost one quarter of all female cancers worldwide, and more than 90% of those who are diagnosed with breast cancer undergo mastectomy or breast conservation surgery. Local anesthetics effectively inhibit the invasion of cancer cells at concentrations that are used in surgical procedures. The limited treatment options for triple-negative breast cancer (TNBC) demonstrate unmet clinical needs. In this study, four local anesthetics, lidocaine, levobupivacaine, bupivacaine, and ropivacaine, were applied to two breast tumor cell types, TNBC MDA-MB-231 cells and triple-positive breast cancer BT-474 cells. In addition to the induction of apoptosis and the suppression of the cellular proliferation rate, the four local anesthetics decreased the levels of reactive oxygen species and increased the autophagy elongation indicator in both cell types. Our combination index analysis with doxorubicin showed that ropivacaine had a synergistic effect on the two cell types, and lidocaine had a synergistic effect only in MDA-MB-231 cells; the others had no synergistic effects on doxorubicin. Lidocaine contributed significantly to the formation of autophagolysosomes in a dose-dependent manner in MDA-MB-231 cells but not in BT-474 cells. Our study demonstrated that the four local anesthetics can reduce tumor growth and proliferation and promote apoptosis and autophagy.

Discovery of LAMP-2A as potential biomarkers for glioblastoma development by modulating apoptosis through N-CoR degradation

BACKGROUND

Lysosome-associated membrane protein type 2A (LAMP-2A) is the key component of chaperone-mediated autophagy (CMA), a cargo-selective lysosomal degradation pathway. Aberrant LAMP-2A expression and CMA activation have been demonstrated in various human malignancies. The study focusing on the intrinsic role of LAMP-2A and CMA in glioblastoma (GBM), and downstream mechanism could provide valuable insight into the pathogenesis and novel therapeutic modality of GBM.

METHODS

The levels of LAMP-2A, nuclear receptor co-repressor (N-CoR), unfolded protein response (UPR) and apoptosis were examined in clinical samples. LAMP-2A siRNA and shRNA were constructed to manipulate CMA activation. The role of CMA and downstream mechanism through degradation of N-CoR and arresting UPR mediated apoptosis were explored in GBM cells and nude mouse xenograft model.

RESULTS

Elevated LAMP-2A and associated decreased N-CoR expression were observed in GBM as compared with peritumoral region and low-grade glioma. Inhibited UPR and apoptosis were observed in GBM with high LAMP-2A expression. In vitro study demonstrated co-localization and interaction between LAMP-2A and N-CoR. LAMP-2A silencing up-regulated N-CoR and aroused UPR pathway, leading to apoptosis, while N-CoR silencing led to an opposite result. In vivo study further confirmed that LAMP-2A inhibition arrested tumor growth by promoting apoptosis.

CONCLUSIONS

Our results demonstrated the central role of CMA in mediating N-CoR degradation and protecting GBM cells against UPR and apoptosis, and provided evidence of LAMP-2A as potential biomarker. Further research focusing on CMA with other tumorigenic process is needed and selective modulators of LAMP-2A remain to be investigated to provide a novel therapeutic strategy for GBM. Video Abstract.

Dysfunction of chaperone-mediated autophagy in human diseases

Chaperone-mediated autophagy (CMA), one of the degradation pathways of proteins, is highly selective to substrates that have KFERQ-like motif. In this process, the substrate proteins are first recognized by the chaperone protein, heat shock cognate protein 70 (Hsc70), then delivered to lysosomal membrane surface where the single-span lysosomal receptor, lysosome-associated membrane protein type 2A (LAMP2A) can bind to the substrate proteins to form a 700 kDa protein complex that allows them to translocate into the lysosome lumen to be degraded by the hydrolytic enzymes. This degradation pathway mediated by CMA plays an important role in regulating glucose and lipid metabolism, transcription, DNA reparation, cell cycle, cellular response to stress and consequently, regulating many aging-associated human diseases, such as neurodegeneration, cancer and metabolic disorders. In this review, we provide an overview of current research on the functional roles of CMA primarily from a perspective of understanding and treating human diseases and also discuss its potential applications for diseases.

A dual-channel fluorescent probe for monitoring pH changes in lysosomes during autophagy

A new fluorescent probe RD for visualizing starvation-induced autophagy in living cells and for distinguishing between neutral and acidic lysosomes in the process of autophagy.

Chaperone-mediated autophagy in cancer: Advances from bench to bedside

Chaperone-mediated autophagy (CMA), a selective form of autophagy, where cellular proteins with KFERQ-like motif are targeted to the lysosome for degradation, is necessary to maintain cellular homeostasis. The role of CMA in neurodegenerative diseases has been extensively studied in the past decades, with defects in the pathway being strongly associated with disease. Recently, accumulating evidence has demonstrated a consistent increase in basal CMA activity in a wide array of cancer cell lines and human tumor biopsies, suggesting a potential link between CMA and cancer. On the other hand, an anti-oncogenic role for CMA under physiological conditions in non-transformed cells is also proposed despite the pro-tumorigenic function of CMA in cancer cells. The growing number of connections between CMA and cancers has generated interest in modulating CMA activity for therapeutic purposes. Here, we describe recent advances in the understanding of the molecular regulation of CMA, and discuss the evidence in support of the contribution of CMA dysfunction to cancers.

Chaperone-mediated autophagy regulates apoptosis and the proliferation of colon carcinoma cells

Chaperone-mediated autophagy (CMA) is one of the three types of autophagy. In recent years, CMA has been shown to be associated with the pathogenesis of several types of cancer. However, whether CMA is involved in the pathogenesis of colorectal cancer (CRC) remains unclear. In this study, we investigated CMA activity in tissue specimens from CRC patients and mouse models of colitis-associated CRC (induced by administration of AOM plus DSS). In addition, we down-regulated CMA in CT26 colon carcinoma cells stably transfected with a vector expressing a siRNA targeting LAMP-2A, the limiting component in the CMA pathway, to explore the role of CMA in these cells. Apoptosis was detected using TUNEL assay, and the apoptosis-related proteins were detected using western blotting. Cell proliferation was assessed using MTT assay, Ki-67 labelling and western blotting for PCNA. We found that LAMP-2A expression was significantly increased in CRC patients and mouse models and varied according to the stage of the disease. Inhibition of CMA in CT26 cells facilitated apoptosis, as evidenced by increased TUNEL immunolabeling, increased expression of Bax and Bnip3, and decreased expression of Bcl-2. Cell proliferation assays showed that inhibition of CMA impeded the proliferation of CT26 cells. These data support the hypothesis that CMA is up-regulated in CRC, and inhibition of CMA may be a new therapeutic strategy for CRC patients.

Ready player one? Autophagy shapes resistance to photodynamic therapy in cancers

Photodynamic therapy (PDT) is a procedure used in cancer therapy that has been shown to be useful for certain indications. Considerable evidence suggests that PDT might be superior to conventional modalities for some indications. In this report, we examine the relationship between PDT responsiveness and autophagy, which can exert a cytoprotective effect. Autophagy is an essential physiological process that maintains cellular homeostasis by degrading dysfunctional or impaired cellular components and organelles via a lysosome-based pathway. Autophagy, which includes macroautophagy and microautophagy, can be a factor that decreases or abolishes responses to various therapeutic protocols. We systematically discuss the mechanisms underlying cell-fate decisions elicited by PDT; analyse the principles of PDT-induced autophagy, macroautophagy and microautophagy; and present evidence to support the notion that autophagy is a critical mechanism in resistance to PDT. A combined strategy involving autophagy inhibitors may be able to further enhance PDT efficacy. Finally, we provide suggestions for future studies, note where our understanding of the relevant molecular regulators is deficient, and discuss the correlations among PDT-induced resistance and autophagy, especially microautophagy.

Chaperone-mediated autophagy substrate proteins in cancer

All intracellular proteins undergo continuous synthesis and degradation. Chaperone-mediated autophagy (CMA) is necessary to maintain cellular homeostasis through turnover of cytosolic proteins (substrate proteins). This degradation involves a series of substrate proteins including both cancer promoters and suppressors. Since activating or inhibiting CMA pathway to treat cancer is still debated, targeting to the CMA substrate proteins provides a novel direction. We summarize the cancer-associated substrate proteins which are degraded by CMA. Consequently, CMA substrate proteins catalyze the glycolysis which contributes to the Warburg effect in cancer cells. The fact that the degradation of substrate proteins based on the CMA can be altered by posttranslational modifications such as phosphorylation or acetylation. In conclusion, targeting to CMA substrate proteins develops into a new anticancer therapeutic approach.

Low intensity focused ultrasound (LOFU) modulates unfolded protein response and sensitizes prostate cancer to 17AAG

The hypoxic tumor microenvironment generates oxidative Endoplasmic Reticulum (ER) stress, resulting in protein misfolding and unfolded protein response (UPR). UPR induces several molecular chaperones including heat-shock protein 90 (HSP90), which corrects protein misfolding and improves survival of cancer cells and resistance to tumoricidal therapy although prolonged activation of UPR induces cell death. The HSP90 inhibitor, 17AAG, has shown promise against various solid tumors, including prostate cancer (PC). However, therapeutic doses of 17AAG elicit systemic toxicity. In this manuscript, we describe a new paradigm where the combination therapy of a non-ablative and non-invasive low energy focused ultrasound (LOFU) and a non-toxic, low dose 17AAG causes synthetic lethality and significant tumoricidal effects in mouse and human PC xenografts. LOFU induces ER stress and UPR in tumor cells without inducing cell death. Treatment with a non-toxic dose of 17AAG further increased ER stress in LOFU treated PC and switch UPR from a cytoprotective to an apoptotic response in tumors resulting significant induction of apoptosis and tumor growth retardation. These observations suggest that LOFU-induced ER stress makes the ultrasound-treated tumors more susceptible to chemotherapeutic agents, such as 17AAG. Thus, a novel therapy of LOFU-induced chemosensitization may be designed for locally advanced and recurrent tumors.

Autophagy and cancer therapy

Autophagy is the process by which cellular material is delivered to lysosomes for degradation and recycling. There are three different types of autophagy, but macroautophagy, which involves the formation of double membrane vesicles that engulf proteins and organelles that fuse with lysosomes, is by far the most studied and is thought to have important context-dependent roles in cancer development, progression, and treatment. The roles of autophagy in cancer treatment are complicated by two important discoveries over the past few years. First, most (perhaps all) anticancer drugs, as well as ionizing radiation, affect autophagy. In most, but not all cases, these treatments increase autophagy in tumor cells. Second, autophagy affects the ability of tumor cells to die after drug treatment, but the effect of autophagy may be to promote or inhibit cell death, depending on context. Here we discuss recent research related to autophagy and cancer therapy with a focus on how these processes may be manipulated to improve cancer therapy.