In vitro antiglioma action of indomethacin is mediated via AMP-activated protein kinase/mTOR complex 1 signalling pathway

Whole milk protein powder separated by low-temperature nanofiltration membrane administration alleviates sepsis-induced myopathy

Sepsis-induced myopathy (SIM) has been recognized as a critical risk factor for the development of acquired muscle weakness among patients in the intensive care unit. These individuals frequently encounter inadequate dietary intake and malnutrition. With the aggravation of the severity of the person's condition, leading to increased skeletal muscle protein breakdown and reduced synthesis, which is an urgent problem to be solved in clinical nutritional treatment. Whole milk protein powder (WMPP) has promising bioactive nutrients and holds promising potential for enhancing skeletal muscle mass. The study was designed to delve into the potential effects and mechanisms of WMPP intervention for increaseing skeletal muscle mass on SIM mice. Our results clearly show that the intervention with WMPP can significantly improve the exercise capacity and skeletal muscle mass in SIM mice. It significantly increases the diameter and cross-sectional area (CSA) of skeletal muscle fibers, while effectively reducing the excessive aggregation of collagen fibers and the abnormal accumulation of adipose tissue in the skeletal muscle of SIM mice. Moreover, WMPP intervention also significantly alleviated the oxidative stress status of mitochondria, which subsequently enhanced the expression of mitochondrial metabolic enzymes. The mechanism may be associated with decreased AMPK phosphorylation in skeletal muscle tissue and simultaneously increased phosphorylation of mTOR, p70S6K1, and 4EBP-1 in SIM mice. In summary, the WMPP intervention significantly enhances exercise capacity and skeletal muscle mass while mitigating the oxidative stress status of mitochondria. Furthermore, it regulates skeletal muscle anabolism via the AMPK/mTOR signaling pathway in SIM mice.

No energy, no autophagy-Mechanisms and therapeutic implications of autophagic response energy requirements

Autophagy is a lysosome-mediated self-degradation process of central importance for cellular quality control. It also provides macromolecule building blocks and substrates for energy metabolism during nutrient or energy deficiency, which are the main stimuli for autophagy induction. However, like most biological processes, autophagy itself requires ATP, and there is an energy threshold for its initiation and execution. We here present the first comprehensive review of this often-overlooked aspect of autophagy research. The studies in which ATP deficiency suppressed autophagy in vitro and in vivo were classified according to the energy pathway involved (oxidative phosphorylation or glycolysis). A mechanistic insight was provided by pinpointing the critical ATP-consuming autophagic events, including transcription/translation/interaction of autophagy-related molecules, autophagosome formation/elongation, autophagosome fusion with the lysosome, and lysosome acidification. The significance of energy-dependent fine-tuning of autophagic response for preserving the cell homeostasis, and potential implications for the therapy of cancer, autoimmunity, metabolic disorders, and neurodegeneration are discussed.

Regulation of cancer stem cells and immunotherapy of glioblastoma (Review)

Glioblastoma (GB) is one of the most adverse diagnoses in oncology. Complex current treatment results in a median survival of 15 months. Resistance to treatment is associated with the presence of cancer stem cells (CSCs). The present review aimed to analyze the mechanisms of CSC plasticity, showing the particular role of β-catenin in regulating vital functions of CSCs, and to describe the molecular mechanisms of Wnt-independent increase of β-catenin levels, which is influenced by the local microenvironment of CSCs. The present review also analyzed the reasons for the low effectiveness of using medication in the regulation of CSCs, and proposed the development of immunotherapy scenarios with tumor cell vaccines, containing heterogenous cancer cells able of producing a multidirectional antineoplastic immune response. Additionally, the possibility of managing lymphopenia by transplanting hematopoietic stem cells from a healthy sibling and using clofazimine or other repurposed drugs that reduce β-catenin concentration in CSCs was discussed in the present study.

Proapoptotic and proautophagy effect of H1-receptor antagonist desloratadine in human glioblastoma cell lines

Glioblastomas are aggressive and usually incurable high-grade gliomas without adequate treatment. In this study, we aimed to investigate the potential of desloratadine to induce apoptosis/autophagy as genetically regulated processes that can seal cancer cell fates. All experiments were performed on U251 human glioblastoma cell line and primary human glioblastoma cell culture. Cytotoxic effect of desloratadine was investigated using MTT and CV assays, while oxidative stress, apoptosis, and autophagy were detected by flow cytometry and immunoblot. Desloratadine treatment decreased cell viability of U251 human glioblastoma cell line and primary human glioblastoma cell culture (IC50 value 50 µM) by an increase of intracellular reactive oxygen species and caspase activity. Also, desloratadine decreased the expression of main autophagy repressor mTOR and its upstream activator Akt and increased the expression of AMPK. Desloratadine exerted dual cytotoxic effect inducing both apoptosis- and mTOR/AMPK-dependent cytotoxic autophagy in glioblastoma cells and primary glioblastoma cell culture.

A Preclinical Systematic Review of the Effects of Chronic Exercise on Autophagy-Related Proteins in Aging Skeletal Muscle

Background: Exercise is one of the most effective interventions for preventing and treating skeletal muscle aging. Exercise-induced autophagy is widely acknowledged to regulate skeletal muscle mass and delay skeletal muscle aging. However, the mechanisms underlying of the effect of different exercises on autophagy in aging skeletal muscle remain unclear.

Methods: A systematic review was performed following an electronic search of SCOPUS, PubMed, Web of Science, ScienceDirect, and Google Scholar and two Chinese electronic databases, CNKI and Wan Fang. All articles published in English and Chinese between January 2010 and January 2022 that quantified autophagy-related proteins in aging skeletal muscle models.

Results: The primary outcome was autophagy assessment, indicated by changes in the levels of any autophagy-associated proteins. A total of fifteen studies were included in the final review. Chronic exercise modes mainly comprise aerobic exercise and resistance exercise, and the intervention types include treadmill training, voluntary wheel running, and ladder training. LC3, Atg5-Atg7/9/12, mTOR, Beclin1, Bcl-2, p62, PGC-1α, and other protein levels were quantified, and the results showed that long-term aerobic exercise and resistance exercise could increase the expression of autophagy-related proteins in aging skeletal muscle (p < 0.05). However, there was no significant difference in short term or high-intensity chronic exercise, and different types and intensities of exercise yielded different levels of significance for autophagy-related protein expression.

Conclusion: Existing evidence reveals that high-intensity exercise may induce excessive autophagy, while low-intensity exercise for a short period (Intervention duration <12 weeks, frequency <3 times/week) may not reach the threshold for exercise-induced autophagy. Precise control of the exercise dose is essential in the long term to maximize the benefits of exercise. Further investigation is warranted to explore the relationship between chronic exercise and different exercise duration and types to substantiate the delaying of skeletal muscle aging by exercise.

Impact of anesthesia and analgesia techniques on glioblastoma progression. A narrative review

Glioblastoma (GBM) is an aggressive malignant CNS tumor with a median survival of 15 months after diagnosis. Standard therapy for GBM includes surgical resection, radiation, and temozolomide. Recently, anesthetics and analgesics have received attention for their potential involvement in mediating tumor growth. This narrative review investigated whether various members of the 2 aforementioned classes of drugs have a definitive impact on GBM progression by summarizing pertinent in vitro, in vivo, and clinical studies. Recent publications regarding general anesthetics have been inconsistent, showing that they can be pro-tumoral or antitumoral depending on the experimental context. The local anesthetic lidocaine has shown consistent antitumoral effects in vitro. Clinical studies looking at anesthetics have not concluded that their use improves patient outcomes. In vitro and in vivo studies looking at opioid involvement in GBM have demonstrated inconsistent findings regarding whether these drugs are pro-tumoral or antitumoral. Nonsteroidal anti-inflammatory drugs, and specifically COX-2 inhibitors, have shown inconsistent findings across multiple studies looking at whether they are beneficial in halting GBM progression. Until multiple repeatable studies show that anesthetics and analgesics can suppress GBM growth, there is no strong evidence to recommend changes in the anesthetic care of these patients.

Transcriptional block of AMPK-induced autophagy promotes glutamate excitotoxicity in nutrient-deprived SH-SY5Y neuroblastoma cells

We investigated the role of autophagy, a controlled lysosomal degradation of cellular macromolecules and organelles, in glutamate excitotoxicity during nutrient deprivation in vitro. The incubation in low-glucose serum/amino acid-free cell culture medium synergized with glutamate in increasing AMP/ATP ratio and causing excitotoxic necrosis in SH-SY5Y human neuroblastoma cells. Glutamate suppressed starvation-triggered autophagy, as confirmed by diminished intracellular acidification, lower LC3 punctuation and LC3-I conversion to autophagosome-associated LC3-II, reduced expression of proautophagic beclin-1 and ATG5, increase of the selective autophagic target NBR1, and decreased number of autophagic vesicles. Similar results were observed in PC12 rat pheochromocytoma cells. Both glutamate-mediated excitotoxicity and autophagy inhibition in starved SH-SY5Y cells were reverted by NMDA antagonist memantine and mimicked by NMDA agonists D-aspartate and ibotenate. Glutamate reduced starvation-triggered phosphorylation of the energy sensor AMP-activated protein kinase (AMPK) without affecting the activity of mammalian target of rapamycin complex 1, a major negative regulator of autophagy. This was associated with reduced mRNA levels of autophagy transcriptional activators (FOXO3, ATF4) and molecules involved in autophagy initiation (ULK1, ATG13, FIP200), autophagosome nucleation/elongation (ATG14, beclin-1, ATG5), and autophagic cargo delivery to autophagosomes (SQSTM1). Glutamate-mediated transcriptional repression of autophagy was alleviated by overexpression of constitutively active AMPK. Genetic or pharmacological AMPK activation by AMPK overexpression or metformin, as well as genetic or pharmacological autophagy induction by TFEB overexpression or lithium chloride, reduced the sensitivity of nutrient-deprived SH-SY5Y cells to glutamate excitotoxicity. These data indicate that transcriptional inhibition of AMPK-dependent cytoprotective autophagy is involved in glutamate-mediated excitotoxicity during nutrient deprivation in vitro.

The gut microbiota attenuates muscle wasting by regulating energy metabolism in chemotherapy-induced malnutrition rats

BACKGROUND

Malnutrition is a common clinical symptom in cancer patients after chemotherapy, which is characterized by muscle wasting and metabolic dysregulation. The regulation of muscle metabolism by gut microbiota has been studied recently. However, there is no direct convincing evidence proving that manipulating gut microbiota homeostasis could regulate muscle metabolic disorder caused by chemotherapy. Here, we investigate the potential role of gut microbiota in the regulation of the muscle metabolism in 5-fluorouracil (5-Fu)-induced malnutrition rat model.

METHODS

Male Sprague-Dawley rats were randomly divided into two groups (n = 8/group): control group and 5-Fu group. In the 5-Fu group, rats received 5-Fu (40 mg/kg/day) by intraperitoneal injection for 4 days, and all rats were raised for 8 days. Nutritional status, muscle function, muscle metabolites, and gut microbiota were assessed. Fecal microbiota transplantation (FMT) was applied to explore the potential regulation of gut microbiota on muscle metabolism.

RESULTS

5-Fu-treated rats exhibited loss of body weight and food intake compared to control group. 5-Fu decreased the levels of total protein and albumin in serum, and significantly increased the levels of IL-6 and TNF-α in muscle tissue. Rats that received 5-Fu displayed concurrent reduction of muscle function and fiber size. Moreover, 5-Fu group showed a distinct profile of gut microbiota compared to control group, including the relative lower abundance of Firmicutes and a higher abundance of Proteobacteria and Verrucomicrobia. Fourteen differential muscle metabolites were identified between two groups, which were mainly related to glycolysis, amino acid metabolism, and TCA cycle pathway. Furthermore, fecal transplantation from healthy rats improved nutritional status and muscle function in 5-Fu-treated rats. Notably, FMT inhibited the inflammatory response in muscle, and reversed the changes of several differential muscle metabolites and energy metabolism in 5-Fu-treated rats.

CONCLUSIONS

Our study demonstrated that gut microbiota played an important role in the regulation of muscle metabolism and promoting muscle energy production in 5-Fu-induced malnutrition rats, suggesting the potential attenuation of chemotherapy-induced muscle wasting by manipulating gut microbiota homeostasis.

Endoplasmic Reticulum Stress Contributes to Indomethacin-Induced Glioma Apoptosis

The dormancy of cellular apoptotic machinery has been highlighted as a crucial factor in therapeutic resistance, recurrence, and poor prognosis in patients with malignancy, such as malignant glioma. Increasing evidence indicates that nonsteroidal anti-inflammatory drugs (NSAIDs) confer chemopreventive effects, and indomethacin has been shown to have a novel chemotherapeutic application targeting glioma cells. To extend these findings, herein, we studied the underlying mechanisms of apoptosis activation caused by indomethacin in human H4 and U87 glioma cells. We found that the glioma cell-killing effects of indomethacin involved both death receptor- and mitochondria-mediated apoptotic cascades. Indomethacin-induced glioma cell apoptosis was accompanied by a series of biochemical changes, including reactive oxygen species generation, endoplasmic reticulum (ER) stress, apoptosis signal-regulating kinase-1 (Ask1) activation, p38 hyperphosphorylation, protein phosphatase 2A (PP2A) activation, Akt dephosphorylation, Mcl-1 and FLICE-inhibiting protein (FLIP) downregulation, Bax mitochondrial distribution, and caspases 3/caspase 8/caspase 9 activation. Data on pharmacological inhibition related to oxidative stress, ER stress, free Ca²⁺, and p38 revealed that the axis of oxidative stress/ER stress/Ask1/p38/PP2A/Akt comprised an apoptotic cascade leading to Mcl-1/FLIP downregulation and glioma apoptosis. Since indomethacin is an emerging choice in chemotherapy and its antineoplastic effects have been demonstrated in glioma tumor-bearing models, the findings further strengthen the argument for turning on the aforementioned axis in order to activate the apoptotic machinery of glioma cells.

Metformin as Potential Therapy for High-Grade Glioma

Metformin (MET), 1,1-dimethylbiguanide hydrochloride, is a biguanide drug used as the first-line medication in the treatment of type 2 diabetes. The recent years have brought many observations showing metformin in its new role. The drug, commonly used in the therapy of diabetes, may also find application in the therapy of a vast variety of tumors. Its effectiveness has been demonstrated in colon, breast, prostate, pancreatic cancer, leukemia, melanoma, lung and endometrial carcinoma, as well as in gliomas. This is especially important in light of the poor options offered to patients in the case of high-grade gliomas, which include glioblastoma (GBM). A thorough understanding of the mechanism of action of metformin can make it possible to discover new drugs that could be used in neoplasm therapy.

Effect of metformin on cell proliferation, apoptosis, migration and invasion in A172 glioma cells and its mechanisms

The purpose of the present study was to determine the effects of metformin on the inhibition of proliferation, apoptosis, invasion and migration of A172 human glioma cells in vitro and determine the underlying mechanism. The effects of metformin at different concentrations (0, 0.1, 1 and 10 mmol/l) on the inhibition of A172 cell proliferation were detected using a 3‑(4,5‑dimethylthiazol‑2‑yl)‑2,5‑diphenyltetrazolium bromide assay. Cell apoptosis was detected by flow cytometry. Caspase‑3 activity was analyzed by spectrophotometry. The invasion and migration of cells were detected by Transwell assays. The levels of Bcl‑2‑associated X protein (Bax), B‑cell lymphoma 2 (Bcl‑2), AMP‑activated protein kinase (AMPK), phosphorylated‑(p)AMPK and mechanistic target of rapamycin (mTOR) protein expression were detected by western blot analysis, and changes in the malondialdehyde (MDA) content and activity of superoxide dismutase (SOD) were determined. Compared with the control group, metformin significantly increased the inhibition of proliferation and apoptosis, and significantly reduced the invasion and migration of A172 cells in dose‑ and time‑dependent manners (P<0.05). In addition, compared with the control group, metformin significantly enhanced the activity of caspase‑3, increased the expression of AMPK/pAMPK/Bax proteins and reduced the expression of mTOR/Bcl‑2 proteins (P<0.05). Metformin increased the MDA content and reduced the activity of SOD in a dose‑dependent manner (P<0.05). Metformin may inhibit glioma cell proliferation, migration and invasion, and promote its apoptosis; the effects may be associated with the AMPK/mTOR signaling pathway and oxidative stress.

Carboranyl Analogues of Ketoprofen with Cytostatic Activity against Human Melanoma and Colon Cancer Cell Lines

Ketoprofen is a widely used nonsteroidal anti-inflammatory drug (NSAID) that also exhibits cytotoxic activity against various cancers. This makes ketoprofen an attractive structural lead for the development of new NSAIDs and cytotoxic agents. Recently, the incorporation of carboranes as phenyl mimetics in structures of established drugs has emerged as an attractive strategy in drug design. Herein, we report the synthesis and evaluation of four novel carborane-containing derivatives of ketoprofen, two of which are prodrug esters with an nitric oxide-releasing moiety. One of these prodrug esters exhibited high cytostatic activity against melanoma and colon cancer cell lines. The most pronounced activity was found in cell lines that are sensitive to oxidative stress, which was apparently induced by the ketoprofen analogue.

Data supporting the inability of indomethacin to induce autophagy in U251 glioma cells

Autophagy, a catabolic process involving intracellular degradation of unnecessary or dysfunctional cellular components through the lysosomal machinery, could act as a prosurvival, as well as a cytotoxic mechanism (Parzych and Klionsky, 2014) [1]. Cyclooxygenase inhibitor indomethacin inhibits proliferation of glioma cells, and has been reported to reduce the activity of the main autophagy repressor mammalian target of rapamycin (mTOR) (Pantovic et al., 2016) [2]. Here we investigated the ability of indomethacin to induce autophagy in U251 human glioma cells. We assessed the influence of indomethacin on intracellular acidification, expression of proautophagic protein beclin-1, and conversion of microtubule-associated protein light chain 3-I (LC3-I) to autophagosome-associated LC3-II, in the presence or absence of lysosomal inhibitors. The effect of genetic and pharmacological downregulation of autophagy on the cytotoxicity of indomethacin was also evaluated. The interpretation of these data can be found in “In vitro antiglioma action of indomethacin is mediated via AMP-activated protein kinase/mTOR complex 1 signaling pathway” (Pantovic et al., 2016; doi:10.1016/j.biocel.2016.12.007) [2].