Caveolin-1 knockdown increases the therapeutic sensitivity of lung cancer to cisplatin-induced apoptosis by repressing Parkin-related mitophagy and activating the ROCK1 pathway

Mitophagy at the crossroads of cancer development: Exploring the role of mitophagy in tumor progression and therapy resistance

Preserving a functional mitochondrial network is crucial for cellular well-being, considering the pivotal role of mitochondria in ensuring cellular survival, especially under stressful conditions. Mitophagy, the selective removal of damaged mitochondria through autophagy, plays a pivotal role in preserving cellular homeostasis by preventing the production of harmful reactive oxygen species from dysfunctional mitochondria. While the involvement of mitophagy in neurodegenerative diseases has been thoroughly investigated, it is becoming increasingly evident that mitophagy plays a significant role in cancer biology. Perturbations in mitophagy pathways lead to suboptimal mitochondrial quality control, catalyzing various aspects of carcinogenesis, including establishing metabolic plasticity, stemness, metabolic reconfiguration of cancer-associated fibroblasts, and immunomodulation. While mitophagy performs a delicate balancing act at the intersection of cell survival and cell death, mounting evidence indicates that, particularly in the context of stress responses induced by cancer therapy, it predominantly promotes cell survival. Here, we showcase an overview of the current understanding of the role of mitophagy in cancer biology and its potential as a target for cancer therapy. Gaining a more comprehensive insight into the interaction between cancer therapy and mitophagy has the potential to reveal novel targets and pathways, paving the way for enhanced treatment strategies for therapy-resistant tumors in the near future.

Dual drug-loaded metal-phenolic networks for targeted magnetic resonance imaging and synergistic chemo-chemodynamic therapy of breast cancer

The development of nanomedicines with simplified compositions and synergistic theranostic functionalities remains a great challenge. Herein, we develop a simple method to integrate both atovaquone (ATO, a mitochondrial inhibitor) and cisplatin within tannic acid (TA)-iron (Fe) networks coated with hyaluronic acid (HA) for targeted magnetic resonance (MR) imaging-guided chemo-chemodynamic synergistic therapy. The formed TFP@ATO-HA displayed good colloidal stability with a mean size of 95.5 nm, which could accumulate at tumor sites after circulation and be specifically taken up by metastatic 4T1 cells overexpressing CD44 receptors. In the tumor microenvironment, TFP@ATO-HA could release ATO/cisplatin and Fe3+ in a pH-responsive manner, deplete glutathione, and generate reactive oxygen species with endogenous H2O2 for chemodynamic therapy (CDT). Additionally, ATO could enhance chemotherapeutic efficacy by inhibiting mitochondrial respiration, relieving hypoxia, and amplifying the CDT effect by decreasing intracellular pH and elevating Fenton reaction efficiency. In vivo experiments demonstrated that TFP@ATO-HA could effectively inhibit tumor growth and suppress lung metastases without obvious systemic toxicity. Furthermore, TFP@ATO-HA exhibited a r1 relaxivity of 2.6 mM-1 s-1 and targeted MR imaging of 4T1 tumors. Dual drug-loaded metal-phenolic networks can be easily prepared and act as effective theranostic nanoplatforms for targeted MR imaging and synergistic chemo-chemodynamic therapy.

Effectively α-Terpineol Suppresses Glioblastoma Aggressive Behavior and Downregulates KDELC2 Expression

BACKGROUND

Glioblastoma (GBM) is notorious for the aggressive behaviors and easily results in chemo-resistance. Studies have shown that the use of herbal medicines as treatments for GBM as limited by the blood-brain barrier (BBB) and glioma stem cells.

PURPOSE

The aim of this study was to investigate the relationship between GBM suppression and α-terpineol, the monoterpenoid alcohol derived from Eucalyptus glubulus and Pinus merkusii.

STUDY DESIGN

Using serial in-vitro and in-vivo studies to confirm the mechanism of α-terpineol on down-regulating GBM development.

METHODS

The 3-[4,5-dimethylthiazol-2-yl)]-2,5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate IC50 of α-terpineol to inhibit GBM cell survival. In order to evaluate the impact of GBM aggressive behaviors by α-terpineol, the analysis of cell migration, invasion and colony formation were implemented. In addition, the ability of tumor spheres and WB of CD44 and OCT3/4 were evaluated under the impression of α-terpineol decreased GBM stemness. The regulation of neoangiogenesis by α-terpineol via the WB of angiogenic factors and human umbilical vein endothelial cells (HUVEC) tube assay. To survey the decided factors of α-terpineol downregulating GBM chemoresistance depended on the impact of O6-methylguanine-DNA methyltransferase (MGMT) expression and autophagy-related factors activation. Additionally, WB and quantitative real-time polymerase chain reaction (qRT/PCR) of KDEL (Lys-Asp-Glu-Leu) containing 2 (KDELC2), endoplasmic reticulum (ER) stress, phosphoinositide 3-kinase (PI3k), mammalian target of rapamycin (mTOR) and mitogen-activated protein kinase (MAPK) cascade signaling factors were examined to explore the mechanism of α-terpineol inhibiting GBM viability. Finally, the orthotopic GBM mouse model was applied to prove the efficacy and toxicity of α-terpineol on regulating GBM survival.

RESULTS

α-terpineol significantly suppressed GBM growth, migration, invasion, angiogenesis and temozolomide (TMZ) resistance. Furthermore, α-terpineol specifically targeted KDELC2 to downregulate Notch and PI3k/mTOR/MAPK signaling pathway. Finally, we also demonstrated that α-terpineol could penetrate the BBB to inhibit GBM proliferation, which resulted in reduced cytotoxicity to vital organs.

CONCLUSION

Compared to published literatures, we firstly proved α-terpineol possessed the capability to inhibit GBM through various mechanisms and potentially decreased the occurrence of chemoresistance, making it a promising alternative therapeutic option for GBM in the future.

Caveolin-1 promotes mitochondrial health and limits mitochondrial ROS through ROCK/AMPK regulation of basal mitophagic flux

Caveolin-1 (CAV1), the main structural component of caveolae, is phosphorylated at tyrosine-14 (pCAV1), regulates signal transduction, mechanotransduction, and mitochondrial function, and plays contrasting roles in cancer progression. We report that CRISPR/Cas9 knockout (KO) of CAV1 increases mitochondrial oxidative phosphorylation, increases mitochondrial potential, and reduces ROS in MDA-MB-231 triple-negative breast cancer cells. Supporting a role for pCAV1, these effects are reversed upon expression of CAV1 phosphomimetic CAV1 Y14D but not non-phosphorylatable CAV1 Y14F. pCAV1 is a known effector of Rho-associated kinase (ROCK) signaling and ROCK1/2 signaling mediates CAV1 promotion of increased mitochondrial potential and decreased ROS production in MDA-MB-231 cells. CAV1/ROCK control of mitochondrial potential and ROS is caveolae-independent as similar results were observed in PC3 prostate cancer cells lacking caveolae. Increased mitochondrial health and reduced ROS in CAV1 KO MDA-MB-231 cells were reversed by knockdown of the autophagy protein ATG5, mitophagy regulator PINK1 or the mitochondrial fission protein Drp1 and therefore due to mitophagy. Use of the mitoKeima mitophagy probe confirmed that CAV1 signaling through ROCK inhibited basal mitophagic flux. Activation of AMPK, a major mitochondrial homeostasis protein inhibited by ROCK, is inhibited by CAV1-ROCK signaling and mediates the increased mitochondrial potential, decreased ROS, and decreased basal mitophagy flux observed in wild-type MDA-MB-231 cells. CAV1 regulation of mitochondrial health and ROS in cancer cells therefore occurs via ROCK-dependent inhibition of AMPK. This study therefore links pCAV1 signaling activity at the plasma membrane with its regulation of mitochondrial activity and cancer cell metabolism through control of mitophagy.

Caveolin-1 in endothelial cells: A potential therapeutic target for atherosclerosis

Atherosclerosis (AS) is a chronic vascular disease characterized by lipid accumulation and the activation of the inflammatory response; it remains the leading nation-wide cause of death. Early in the progression of AS, stimulation by pro-inflammatory agonists (TNF-α, LPS, and others), oxidized lipoproteins (ox-LDL), and biomechanical stimuli (low shear stress) lead to endothelial cell activation and dysfunction. Consequently, it is crucial to investigate how endothelial cells respond to different stressors and ways to alter endothelial cell activation in AS development, as they are the earliest cells to respond. Caveolin-1 (Cav1) is a 21-24-kDa membrane protein located in caveolae and highly expressed in endothelial cells, which plays a vital role in regulating lipid transport, inflammatory responses, and various cellular signaling pathways and has atherogenic effects. This review summarizes recent studies on the structure and physiological functions of Cav1 and outlines the potential mechanisms it mediates in AS development. Included are the roles of Cav1 in the regulation of endothelial cell autophagy, response to shear stress, modulation of the eNOS/NO axis, and transduction of inflammatory signaling pathways. This review provides a rationale for proposing Cav1 as a novel target for the prevention of AS, as well as new ideas for therapeutic strategies for early AS.

Cisplatin ototoxicity mechanism and antagonistic intervention strategy: a scope review

Cisplatin is a first-line chemotherapeutic agent in the treatment of malignant tumors with remarkable clinical effects and low cost. However, the ototoxicity and neurotoxicity of cisplatin greatly limit its clinical application. This article reviews the possible pathways and molecular mechanisms of cisplatin trafficking from peripheral blood into the inner ear, the toxic response of cisplatin to inner ear cells, as well as the cascade reactions leading to cell death. Moreover, this article highlights the latest research progress in cisplatin resistance mechanism and cisplatin ototoxicity. Two effective protective mechanisms, anti-apoptosis and mitophagy activation, and their interaction in the inner ear are discussed. Additionally, the current clinical preventive measures and novel therapeutic agents for cisplatin ototoxicity are described. Finally, this article also forecasts the prospect of possible drug targets for mitigating cisplatin-induced ototoxicity. These include the use of antioxidants, inhibitors of transporter proteins, inhibitors of cellular pathways, combination drug delivery methods, and other mechanisms that have shown promise in preclinical studies. Further research is needed to evaluate the efficacy and safety of these approaches.

HDAC3 deficiency protects against acute lung injury by maintaining epithelial barrier integrity through preserving mitochondrial quality control

Sepsis is one common cause of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), which is closely associated with high mortality in intensive care units (ICU). Histone deacetylase 3 (HDAC3) serves as an important epigenetic modifying enzyme which could affect chromatin structure and transcriptional regulation. Here, we explored the effects of HDAC3 in type II alveolar epithelial cells (AT2) on lipopolysaccharide (LPS)-induced ALI and shed light on potential molecular mechanisms. We generated ALI mouse model with HDAC3 conditional knockout mice (Sftpc-cre; Hdac3^f/f) in AT2 and the roles of HDAC3 in ALI and epithelial barrier integrity were investigated in LPS-treated AT2. The levels of HDAC3 were significantly upregulated in lung tissues from mice with sepsis and in LPS-treated AT2. HDAC3 deficiency in AT2 not only decreased inflammation, apoptosis, and oxidative stress, but also maintained epithelial barrier integrity. Meanwhile, HDAC3 deficiency in LPS-treated AT2 preserved mitochondrial quality control (MQC), evidenced by the shift of mitochondria from fission into fusion, decreased mitophagy, and improved fatty acid oxidation (FAO). Mechanically, HDAC3 promoted the transcription of Rho-associated protein kinase 1 (ROCK1) in AT2. In the context of LPS stimulation, the upregulated ROCK1 elicited by HDAC3 could be phosphorylated by Rho-associated (RhoA), thus disturbing MQC and triggering ALI. Furthermore, we found that forkhead box O1 (FOXO1) was one of transcription factors of ROCK1. HDAC3 directly decreased the acetylation of FOXO1 and promoted its nuclear translocation in LPS-treated AT2. Finally, HDAC3 inhibitor RGFP966 alleviated epithelial damage and improved MQC in LPS-treated AT2. Altogether, HDAC3 deficiency in AT2 alleviated sepsis-induced ALI by preserving mitochondrial quality control via FOXO1-ROCK1 axis, which provided a potential strategy for the treatment of sepsis and ALI.

METTL3 promotes chemoresistance in small cell lung cancer by inducing mitophagy

BACKGROUND

Small cell lung cancer (SCLC) is the most aggressive subtype of lung cancer. Although most patients are initially sensitive to first-line combination chemotherapy with cisplatin and etoposide, chemotherapy drug resistance easily develops and quickly leads to tumour progression. Therefore, understanding the mechanisms of chemotherapy drug resistance and how to reverse it is key to improving the prognosis of patients with SCLC. Moreover, N6-methyladenosine (m6A) is the most abundant mRNA modification and is catalysed by the methyltransferase complex, in which methyltransferase-like 3 (METTL3) is the sole catalytic subunit.

METHODS

The effects of METTL3 on chemoresistance in SCLC cells were determined using qRT-PCR, Western blotting, immunohistochemistry, cell counting kit (CCK-8) assays, flow cytometry, and tumorigenicity experiments. Methylated RNA immunoprecipitation sequencing (MeRIP-seq), MeRIP qPCR, immunofluorescence, and drug inhibitor experiments were performed to confirm the molecular mechanism of Decapping Protein 2 (DCP2), which is involved in the chemoresistance of SCLC.

RESULTS

In the present study, we found that METTL3 is a marker for poor SCLC prognosis, and it is highly expressed in chemoresistant SCLC cells. METTL3 promotes SCLC chemoresistance by positively regulating mitophagy. METTL3 induces m6A methylation of DCP2 and causes the degradation of DCP2, which promotes mitochondrial autophagy through the Pink1-Parkin pathway, leading to chemotherapy resistance. We also found that STM2457, a novel METTL3 inhibitor, can reverse SCLC chemoresistance.

CONCLUSIONS

The m6A methyltransferase METTL3 regulates Pink1-Parkin pathway-mediated mitophagy and mitochondrial damage in SCLC cells by targeting DCP2, thereby promoting chemotherapy resistance in patients with SCLC.

Vitamin B12 Ameliorates the Pathological Phenotypes of Multiple Parkinson's Disease Models by Alleviating Oxidative Stress

Parkinson's disease (PD) is the second most common neurodegenerative disease characterized by progressive loss of dopaminergic neurons in the substantia nigra of the midbrain. The etiology of PD has yet to be elucidated, and the disease remains incurable. Increasing evidence suggests that oxidative stress is the key causative factor of PD. Due to their capacity to alleviate oxidative stress, antioxidants hold great potential for the treatment of PD. Vitamins are essential organic substances for maintaining the life of organisms. Vitamin deficiency is implicated in the pathogenesis of various diseases, such as PD. In the present study, we investigated whether administration of vitamin B12 (VB12) could ameliorate PD phenotypes in vitro and in vivo. Our results showed that VB12 significantly reduced the generation of reactive oxygen species (ROS) in the rotenone-induced SH-SY5Y cellular PD model. In a Parkin gene knockout C. elegans PD model, VB12 mitigated motor dysfunction. Moreover, in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse PD model, VB12 also displayed protective effects, including the rescue of mitochondrial function, dopaminergic neuron loss, and movement disorder. In summary, our results suggest that vitamin supplementation may be a novel method for the intervention of PD, which is safer and more feasible than chemical drug treatment.

Role of Caveolin-1 in Sepsis – A Mini-Review

Sepsis is a generalized disease characterized by an extreme response to a severe infection. Moreover, challenges remain in the diagnosis, treatment and management of septic patients. In this mini-review we demonstrate developments on cellular pathogenesis and the role of Caveolin-1 (Cav-1) in sepsis. Studies have shown that Cav-1 has a significant role in sepsis through the regulation of membrane traffic and intracellular signaling pathways. In addition, activation of apoptosis/autophagy is considered relevant for the progression and development of sepsis. However, how Cav-1 is involved in sepsis remains unclear, and the precise mechanisms need to be further investigated. Finally, the role of Cav-1 in altering cell permeability during inflammation, in sepsis caused by microorganisms, apoptosis/autophagy activation and new therapies under study are discussed in this mini-review.

Deciphering the relationship between caveolae-mediated intracellular transport and signalling events

The caveolae-mediated transport across polarized epithelial cell barriers has been largely deciphered in the last decades and is considered the second essential intracellular transfer mechanism, after the clathrin-dependent endocytosis. The basic cell biology knowledge was supplemented recently, with the molecular mechanisms beyond caveolae generation implying the key contribution of the lipid-binding proteins (the structural protein Caveolin and the adapter protein Cavin), along with the bulb coat stabilizing molecules PACSIN-2 and Eps15 homology domain protein-2. The current attention is focused also on caveolae architecture (such as the bulb coat, the neck, the membrane funnel inside the bulb, and the associated receptors), and their specific tasks during the intracellular transport of various cargoes. Here, we resume the present understanding of the assembly, detachment, and internalization of caveolae from the plasma membrane lipid raft domains, and give an updated view on transcytosis and endocytosis, the two itineraries of cargoes transport via caveolae. The review adds novel data on the signalling molecules regulating caveolae intracellular routes and on the transport dysregulation in diseases. The therapeutic possibilities offered by exploitation of Caveolin-1 expression and caveolae trafficking, and the urgent issues to be uncovered conclude the review.

New dawn for cancer cell death: Emerging role of lipid metabolism

BACKGROUND

Resistance to cell death, a protective mechanism for removing damaged cells, is a "Hallmark of Cancer" that is essential for cancer progression. Increasing attention to cancer lipid metabolism has revealed a number of pathways that induce cancer cell death.

SCOPE OF REVIEW

We summarize emerging concepts regarding lipid metabolic reprogramming in cancer that is mainly involved in lipid uptake and trafficking, de novo synthesis and esterification, fatty acid synthesis and oxidation, lipogenesis, and lipolysis. During carcinogenesis and progression, continuous metabolic adaptations are co-opted by cancer cells, to maximize their fitness to the ever-changing environmental. Lipid metabolism and the epigenetic modifying enzymes interact in a bidirectional manner which involves regulating cancer cell death. Moreover, lipids in the tumor microenvironment play unique roles beyond metabolic requirements that promote cancer progression. Finally, we posit potential therapeutic strategies targeting lipid metabolism to improve treatment efficacy and survival of cancer patient.

MAJOR CONCLUSIONS

The profound comprehension of past findings, current trends, and future research directions on resistance to cancer cell death will facilitate the development of novel therapeutic strategies targeting the lipid metabolism.

The Core Mechanism of Yiqi Yangjing Decoction Inhibiting Nonsmall-Cell Lung Cancer

Background

Yiqi Yangjing prescription (YQYJ) is a traditional Chinese medicine prescription used for treating lung cancer. It has a significant effect on enhancing efficacy, reducing toxic symptoms, and improving patients' physical well-being. The effective inhibitory effect on nonsmall-cell lung cancer (NSCLC) has been demonstrated in vitro and in vivo. However, the mechanism of action and the material basis still remain unclear.

Methods

In this study, we explored this mechanism using network pharmacology, after which we explored the pharmacodynamics and the action mechanism of YQYJ using cell viability evaluation, plate clone formation assay, flow cytometry, real-time quantitative PCR, and Western blot.

Results

The enrichment results showed that there were 50 active components and 68 core targets related to YQYJ inhibiting NSCLC, including quercetin, luteolin, gamatin, kaempferol, heat shock protein HSP 90-alpha (HSP90AA1), cyclin-dependent kinase 2 (CDK2), epidermal growth factor receptor (EGFR), signal transducer and activator of transcription 3 (STAT3), and others. Among them, quercetin and kaempferol revealed the best binding effect with core targets. Most importantly, YQYJ promoted A549 cells from the quiescent phase into the proliferative phase to enhance the sensitivity of A549 cells to YQYJ and inhibited the proliferation of A549 cells significantly (P < 0.05). The A549 cells were blocked in both S and G2/M phases while the apoptosis ratio was increased. The proliferation score of A549 cells treated with YQYJ was significantly reduced compared to A549 cells in the proliferative phase (P < 0.05). This regulatory effect was related to the expression regulation of HSP90AA1, CDK2, STAT3, and phosphor-STAT3 (p-STAT3) by YQYJ, kaempferol, and quercetin.

Conclusion

Our results suggested that the inhibition of NSCLC via YQYJ had multicomponent and multitarget characteristics. Its core mechanism is related to the regulation of the cell cycle, proliferation, and apoptosis of NSCLC. This study provides a direction and scientific basis for exploring the future mechanism of YQYJ for the treatment of NSCLC.

Is Autophagy Always a Barrier to Cisplatin Therapy?

Cisplatin has long been a first-line chemotherapeutic agent in the treatment of cancer, largely for solid tumors. During the course of the past two decades, autophagy has been identified in response to cancer treatments and almost uniformly detected in studies involving cisplatin. There has been increasing recognition of autophagy as a critical factor affecting tumor cell death and tumor chemoresistance. In this review and commentary, we introduce four mechanisms of resistance to cisplatin followed by a discussion of the factors that affect the role of autophagy in cisplatin-sensitive and resistant cells and explore the two-sided outcomes that occur when autophagy inhibitors are combined with cisplatin. Our goal is to analyze the potential for the combinatorial use of cisplatin and autophagy inhibitors in the clinic.

Insight Into Rho Kinase Isoforms in Obesity and Energy Homeostasis

Obesity and associated complications increasingly jeopardize global health and contribute to the rapidly rising prevalence of type 2 diabetes mellitus and obesity-related diseases. Developing novel methods for the prevention and treatment of excess body adipose tissue expansion can make a significant contribution to public health. Rho kinase is a Rho-associated coiled-coil-containing protein kinase (Rho kinase or ROCK). The ROCK family including ROCK1 and ROCK2 has recently emerged as a potential therapeutic target for the treatment of metabolic disorders. Up-regulated ROCK activity has been involved in the pathogenesis of all aspects of metabolic syndrome including obesity, insulin resistance, dyslipidemia and hypertension. The RhoA/ROCK-mediated actin cytoskeleton dynamics have been implicated in both white and beige adipogenesis. Studies using ROCK pan-inhibitors in animal models of obesity, diabetes, and associated complications have demonstrated beneficial outcomes. Studies via genetically modified animal models further established isoform-specific roles of ROCK in the pathogenesis of metabolic disorders including obesity. However, most reported studies have been focused on ROCK1 activity during the past decade. Due to the progress in developing ROCK2-selective inhibitors in recent years, a growing body of evidence indicates more attention should be devoted towards understanding ROCK2 isoform function in metabolism. Hence, studying individual ROCK isoforms to reveal their specific roles and principal mechanisms in white and beige adipogenesis, insulin sensitivity, energy balancing regulation, and obesity development will facilitate significant breakthroughs for systemic treatment with isoform-selective inhibitors. In this review, we give an overview of ROCK functions in the pathogenesis of obesity and insulin resistance with a particular focus on the current understanding of ROCK isoform signaling in white and beige adipogenesis, obesity and thermogenesis in adipose tissue and other major metabolic organs involved in energy homeostasis regulation.

Caveolin-1 Regulates Cellular Metabolism: A Potential Therapeutic Target in Kidney Disease

The kidney is an energy-consuming organ, and cellular metabolism plays an indispensable role in kidney-related diseases. Caveolin-1 (Cav-1), a multifunctional membrane protein, is the main component of caveolae on the plasma membrane. Caveolae are represented by tiny invaginations that are abundant on the plasma membrane and that serve as a platform to regulate cellular endocytosis, stress responses, and signal transduction. However, caveolae have received increasing attention as a metabolic platform that mediates the endocytosis of albumin, cholesterol, and glucose, participates in cellular metabolic reprogramming and is involved in the progression of kidney disease. It is worth noting that caveolae mainly depend on Cav-1 to perform the abovementioned cellular functions. Furthermore, the mechanism by which Cav-1 regulates cellular metabolism and participates in the pathophysiology of kidney diseases has not been completely elucidated. In this review, we introduce the structure and function of Cav-1 and its functions in regulating cellular metabolism, autophagy, and oxidative stress, focusing on the relationship between Cav-1 in cellular metabolism and kidney disease; in addition, Cav-1 that serves as a potential therapeutic target for treatment of kidney disease is also described.

Circ_PIP5K1A regulates cisplatin resistance and malignant progression in non-small cell lung cancer cells and xenograft murine model via depending on miR-493-5p/ROCK1 axis

Background

Chemoresistance limits the therapeutic effect of cisplatin (DDP) on non-small cell lung cancer (NSCLC). Circular RNAs (circRNAs) function as important regulators in chemoresistance. This study aimed to explore the regulation of circRNA Phosphatidylinositol-4-Phosphate 5-Kinase Type 1 Alpha (circ_PIP5K1A) in DDP resistance.

Methods

The expression analysis of circ_PIP5K1A, micoRNA-493-5p (miR-493-5p) and Rho Associated Coiled-Coil Containing Protein Kinase 1 (ROCK1) was conducted through reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Cell sensitivity was determined using 3-(4,5-dimethylthiazol-2-y1)-2,5-diphenyl tetrazolium bromide (MTT) assay. Cell proliferation and cell viability were evaluated by colony formation assay and MTT assay, respectively. Cell cycle and apoptosis detection was performed via flow cytometry. Cell motility was examined by transwell migration or invasion assay. Dual-luciferase reporter assay was applied to confirm the target binding. ROCK1 protein level was assayed via Western blot. In vivo assay was carried out using xenograft model in mice.

Results

Circ_PIP5K1A level was abnormally increased in DDP-resistant NSCLC tissues and cells. Silencing circ_PIP5K1A reduced DDP resistance, proliferation, cell cycle progression and cell motility in DDP-resistant NSCLC cells. Circ_PIP5K1A directly interacted with miR-493-5p in NSCLC cells. The function of circ_PIP5K1A was dependent on the negative regulation of miR-493-5p. MiR-493-5p directly targeted ROCK1 and circ_PIP5K1A regulated the ROCK1 level via acting as a sponge of miR-493-5p. Overexpression of miR-493-5p inhibited chemoresistance and cancer progression by downregulating ROCK1 expression in DDP-resistant NSCLC cells. Circ_PIP5K1A regulated DDP sensitivity in vivo via the miR-493-5p/ROCK1 axis.

Conclusion

These findings suggested that circ_PIP5K1A upregulated the ROCK1 expression to promote DDP resistance and cancer progression in NSCLC by sponging miR-493-5p.

Caveolin1: its roles in normal and cancer stem cells

PURPOSE

Stem cells are characterized by the capability of self-renewal and multi-differentiation. Normal stem cells, which are important for tissue repair and tissue regeneration, can be divided into embryonic stem cells (ESCs) and somatic stem cells (SSCs) depending on their origin. As a subpopulation of cells within cancer, cancer stem cells (CSCs) are at the root of therapeutic resistance. Tumor-initiating cells (TICs) are necessary for tumor initiation. Caveolin1 (Cav1), a membrane protein located at the caveolae, participates in cell lipid transport, cell migration, cell proliferation, and cell signal transduction. The purpose of this review was to explore the relationship between Cav1 and stem cells.

RESULTS

In ESCs, Cav1 is beneficial for self-renewal, proliferation, and migration. In SSCs, Cav1 exhibits positive or/and negative effects on stem cell self-renewal, differentiation, proliferation, migration, and angiogenic capacity. Cav1 deficiency impairs normal stem cell-based tissue repair. In CSCs, Cav1 inhibits or/and promotes CSC self-renewal, differentiation, invasion, migration, tumorigenicity ability, and CSC formation. And suppressing Cav1 promotes chemo-sensitivity in CSCs and TICs.

CONCLUSION

Cav1 shows dual roles in stem cell biology. Targeting the Cav1-stem cell axis would be a new way for tissue repair and cancer drug resistance.

Folic acid deficiency damages male reproduction via endoplasmic reticulum stress-associated PERK pathway induced by Caveolin-1 in mice

Folic acid is critical to maintaining normal male reproductive function. Endoplasmic reticulum (ER) stress plays a crucial role in folic acid deficiency. Studies have shown that Caveolin-1 (Cav-1) is involved in ER stress, but the specific mechanism in male reproduction is still unclear. This study aimed to investigate the effects of folic acid deficiency on spermatogenesis and elucidate the underlying mechanisms. C57BL/6 mice fed with folic acid deficiency induced diet(0.3 mg/kg) were used. A significant decrease in the sperm concentration in the folic acid deficiency group was observed. Meanwhile, folic acid deficiency decreased Cav-1 expression in the testis tissue and increased endoplasmic reticulum stress-related PERK, eIF2α, ATF4, CHOP gene expression. Our results suggest that folic acid deficiency can affect male reproduction through the Cav-1-PERK-eIFα-ATF4-CHOP pathway.Abbreviations: ATF4: activating transcription factor 4; Ca2+: calcium ion; Cav-1: Caveolin-1; CCK-8: cell counting kit-8; CHOP: CCAAT-enhancer-binding protein homologous protein; DNA: Deoxyribonucleic acid; DSB: double strand breakage; eIF2α: eukaryotic Initiation Factor 2 alpha; ER: endoplasmic reticulum; FD: folic acid deficiency; FITC: fluorescein isothiocyanate; HE: hematoxylin and eosin; H3K4me3: histone H3 lysine 4 trimethylation; PERK: protein kinase RNA-like endoplasmic reticulum kinase; PI: propidium iodide; RT-qPCR: quantitative reverse transcription PCR; TUNEL: TdT mediated dUTP Nick End Labeling.

Role of caveolin-1 in human organ function and disease: friend or foe?

Caveolin-1 (Cav-1) is a structural protein component of caveolae, which are invaginations of the plasma membrane involved in various cellular processes, including endocytosis, extracellular matrix organization, cholesterol distribution, cell migration, and signaling. Mounting evidence over the last 10-15 years has demonstrated a central role of Cav-1 in many diseases, such as cancer, diabetes, and fibrosis. Cav-1 plays positive and negative roles in various diseases through its different regulation pathways. Here, we review the current knowledge on Cav-1 in different diseases and discuss the role of this protein in human organs and diseases.

Mitophagy in carcinogenesis, drug resistance and anticancer therapeutics

The mitochondrion is an organelle that plays a vital role in energy production, cytoplasmic protein degradation and cell death. Mitophagy is an autophagic procedure that specifically clears damaged mitochondria and maintains its homeostasis. Emerging evidence indicates that mitophagy is involved in many physiological processes, including cellular homeostasis, cellular differentiation and nerve protection. In this review, we describe the regulatory mechanisms of mitophagy in mammals and yeasts and highlight the recent advances relevant to its function in carcinogenesis and drug resistance. Finally, a section has been dedicated to describing the role of mitophagy in anticancer therapeutics, which is a new frontier that offers a precise and promising strategy.

The role of caveolin-1 in the biofate and efficacy of anti-tumor drugs and their nano-drug delivery systems

As one of the most important components of caveolae, caveolin-1 is involved in caveolae-mediated endocytosis and transcytosis pathways, and also plays a role in regulating the cell membrane cholesterol homeostasis and mediating signal transduction. In recent years, the relationship between the expression level of caveolin-1 in the tumor microenvironment and the prognostic effect of tumor treatment and drug treatment resistance has also been widely explored. In addition, the interplay between caveolin-1 and nano-drugs is bidirectional. Caveolin-1 could determine the intracellular biofate of specific nano-drugs, preventing from lysosomal degradation, and facilitate them penetrate into deeper site of tumors by transcytosis; while some nanocarriers could also affect caveolin-1 levels in tumor cells, thereby changing certain biophysical function of cells. This article reviews the role of caveolin-1 in tumor prognosis, chemotherapeutic drug resistance, antibody drug sensitivity, and nano-drug delivery, providing a reference for the further application of caveolin-1 in nano-drug delivery systems.

Caveolin-1 promotes radioresistance via IRGM-regulated autophagy in lung cancer

Background

Radiotherapy is the standard therapeutic approach for non-small cell lung cancers (NSCLCs). However, radiotherapy resistance accounts for major treatment failures in NSCLC patients. Recently, targeting autophagy-related signaling has shown potential to improve radiotherapy. Furthermore, some studies have reported that caveolin-1 (Cav1), a primary scaffolding protein of caveolae, is positively associated with NSCLC progression and cell autophagy. However, the function of Cav1-mediated autophagy in NSCLC radioresistance remains largely unknown.

Methods

The NSCLC irradiation (IR)-resistant cell lines H358-IRR and A549-IRR were used for in vitro analysis. Real-time quantitative PCR (qPCR), western blot, cell counting kit-8 (CCK-8), colony formation and transmission electron microscopy analyses were performed to explore the relationship between Cav1 and immunity-related GTPase family M protein (IRGM)-regulated autophagy in the radiation resistance of lung cancers.

Results

Cav1 was significantly overexpressed in H358-IRR and A549-IRR cells compared to their parental counterparts. Knockdown of Cav1 significantly decreased the proliferation of IR-resistant NSCLC cells. Combinational treatment of IR and siRNA of Cav1 showed enhanced inhibition of the cell viability and colony formation of IR-resistant NSCLC cells. In addition, Cav1 overexpression could upregulate the autophagic proteins microtubule associated protein 1 light chain 3 II (LC3 II), Beclin-1 and Sequestosome 1 (SQSTM1/p62) in parental NSCLC cells, while Cav1 downregulation by siRNA inhibited the expression of LC3 II, Beclin-1 and p62 and the formation of autophagosomes in IR-resistant NSCLC cells. Furthermore, we observed that IRGM was downregulated after knockdown of Cav1 in IR-resistant NSCLC cells. Thus, Cav1 was observed to promote autophagy and increase IR-resistant cell survival by targeting IRGM.

Conclusions

The results of our study showed that Cav1 is involved in the development of IR resistance in NSCLC through IRGM-regulated autophagy and can be considered as a potential therapeutic target for improving the radiosensitivity of NSCLC.

Highly penetrating nanobubble polymer enhances LINC00511-siRNA delivery for improving the chemosensitivity of triple-negative breast cancer

Ultrasound-mediated nanobubble destruction (UMND), which can utilize the physical energy of ultrasound irradiation to improve the transfer efficiency to target cells is becoming one of the most promising carriers for gene delivery. The purpose of this study was to establish cell-penetrating peptide (CPP)-loaded nanobubbles (CNBs) connected with long intergenic nonprotein coding RNA 00511-small interfering RNA (LINC00511-siRNA) and evaluate its feasibility for improving the chemosensitivity of triple-negative breast cancer in vitro. First, fluorescence imaging confirmed the loading of siLINC00511 on CNBs, and the CNBs-siLINC00511 were characterized by the Zetasizer Nano ZS90 analyzer and transmission electron microscopy. Next, cell counting kit 8 assay was used to detect the inhibitory activity of cisplatin on the proliferation of MDA-MB-231 cells, and the 50% inhibition concentration value before and after transfer was calculated. Finally, the silencing effect of siLINC00511 was evaluated in vitro using an apoptosis assay, transwell assay, real time-PCR and western blotting. UMND combined with CNBs could effectively transfer the siRNA to MDA-MB-231 cells, thus evidently reducing the expression of LINC00511. Furthermore, inhibitory activity of cisplatin on MDA-MB-231 cells was enhanced after downregulation of LINC00511 expression. Downregulation of LINC00511 alters expression of cell cycle-related (CDK 6) and apoptosis-related (Bcl-2 and Bax) proteins in MDA-MB-231 cells. These results suggested that siRNA-CNBs may be an ideal vector for the treatment of tumors, with high efficiency RNA interference under the combined action of UMND. It may provide a new therapeutic method for triple negative breast cancer.

Nano delivery of natural substances as prospective autophagy modulators in glioblastoma

Glioblastoma is the most destructive type of malignant brain tumor in humans due to cancer relapse. Latest studies have indicated that cancer cells are more reliant on autophagy for survival than non-cancer cells. Autophagy is entitled as programmed cell death type II and studies imply that it is a comeback of cancer cells to innumerable anti-cancer therapies. To diminish the adverse consequences of chemotherapeutics, numerous herbs of natural origin have been retained in cancer treatments. Additionally, autophagy induction occurs via their tumor suppressive actions that could cause cell senescence and increase apoptosis-independent cell death. However, most of the drugs have poor solubility and thus nano drug delivery systems possess excessive potential to improve the aqueous solubility and bioavailability of encapsulated drugs. There is a pronounced need for more therapies for glioblastoma treatment and hereby, the fundamental mechanisms of natural autophagy modulators in glioblastoma are prudently reviewed in this article.

Triptolide-induced apoptosis in non-small cell lung cancer via a novel miR204-5p/Caveolin-1/Akt-mediated pathway

Lung cancer is one of the most prevalent malignancies world-wide with non-small cell lung cancer (NSCLC) comprising nearly 80% of all cases. Unfortunately, many lung cancer patients are diagnosed at advanced stages of the disease with an associated poor prognosis. Recently, the Chinese herb root extract Triptolide/Minnelide (TL) has shown significant promise as a therapeutic agent for NSCLC treatment both in vitro and in vivo. The aim of this study was to investigate the underlying mechanism(s) of action regarding TL-induced cytotoxicity in NSCLC. We demonstrate that triptolide treatment of A549 and H460 NSCLC cells decreases Caveolin-1 (CAV-1) mRNA/protein expression, resulting in activation of the Akt/Bcl-2-mediated mitochondrial apoptosis pathway. CAV-1 down-regulation was triggered by Micro-RNA 204-5p (miR204-5p) up-regulation and could be significantly blocked by pre-treatment with both Sirt-1/Sirt-3 specific siRNA and SIRT-1/SIRT-3 enzyme inhibitors, EX-527 and nicotinamide. Overall, our results provide evidence for a novel mechanism by which TL exerts its cytotoxic effects on NSCLC via CAV-1 down-regulation. Furthermore, these findings demonstrate a pivotal role for TL induction of the Akt/Bax pathway in apoptosis of human lung cancer.

Metformin Inhibits Propofol-Induced Apoptosis of Mouse Hippocampal Neurons HT-22 Through Downregulating Cav-1

Objective

To elucidate the neuroprotective function of metformin in suppressing propofol-induced apoptosis of HT-22 cells.

Methods

HT-22 cells were treated with 0, 10 or 100 μmol/L propofol, followed by determination of their proliferative ability. Subsequently, changes in proliferation and apoptosis of propofol-treated HT-22 cells induced with metformin were assessed. Apoptosis-associated genes in HT-22 cells were detected by Western blot. At last, regulatory effects of Cav-1 on propofol and metformin-treated HT-22 cells were examined.

Results

Propofol treatment dose-dependently decreased proliferative ability and increased apoptosis ability in HT-22 cells, which were partially blocked by metformin administration. Upregulated Bcl-2 and downregulated Bax were observed in propofol-treated HT-22 cells following metformin administration. In addition, Cav-1 level in HT-22 cells was regulated by metformin treatment. Notably, metformin reversed propofol-induced apoptosis stimulation and proliferation decline in HT-22 cells via downregulating Cav-1.

Conclusion

In our study, we found that propofol could induce apoptosis of HT-22 cells and metformin could rescue the apoptosis effect regulated by propofol. Then, we found that metformin protects propofol-induced neuronal apoptosis via downregulating Cav-1.

The caveolar-mitochondrial interface: regulation of cellular metabolism in physiology and pathophysiology

The plasma membrane is an important cellular organelle that is often overlooked in terms of a primary factor in regulating physiology and pathophysiology. There is emerging evidence to suggest that the plasma membrane serves a greater purpose than a simple barrier or transporter of ions. New paradigms suggest that the membrane serves as a critical bridge to connect extracellular to intracellular communication particularly to regulate energy and metabolism by forming physical and biochemical associations with intracellular organelles. This review will focus on the relationship of a particular membrane microdomain - caveolae - with mitochondria and the particular implication of this to physiology and pathophysiology.

Multifaceted Roles of Caveolin-1 in Lung Cancer: A New Investigation Focused on Tumor Occurrence, Development and Therapy

Lung cancer is one of the most common and malignant cancers with extremely high morbidity and mortality in both males and females. Although traditional lung cancer treatments are fast progressing, there are still limitations. Caveolin-1 (Cav-1), a main component of caveolae, participates in multiple cellular events such as immune responses, endocytosis, membrane trafficking, cellular signaling and cancer progression. It has been found tightly associated with lung cancer cell proliferation, migration, apoptosis resistance and drug resistance. In addition to this, multiple bioactive molecules have been confirmed to target Cav-1 to carry on their anti-tumor functions in lung cancers. Cav-1 can also be a predictor for lung cancer patients’ prognosis. In this review, we have summarized the valuable research on Cav-1 and lung cancer in recent years and discussed the multifaceted roles of Cav-1 on lung cancer occurrence, development and therapy, hoping to provide new insights into lung cancer treatment.