d-Pinitol protects against endoplasmic reticulum stress and apoptosis in hepatic ischemia-reperfusion injury via modulation of AFT4-CHOP/GRP78 and caspase-3 signaling pathways.

Hepatic ischemia-reperfusion injury (IRI) is a major unavoidable clinical problem often accompanying various liver surgery and transplantation. d-Pinitol, a cyclic polyol, exhibits hepatoprotective efficacy. The objective of this study is to determine the possible mechanism of action of pinitol against endoplasmic reticulum (ER) stress regulation-mediated hepatic IRI and compare its effects with thymoquinone (TQ) in experimental rats. Male Sprague Dawley rats were pre-treated orally with either vehicle (DMSO) or d-Pinitol (5, 10, and 20 mg/kg) or TQ (30 mg/kg) for 21 days and subjected to 60 min of partial hepatic ischemia followed by 24 h of reperfusion. Pre-treatment with pinitol (10 and 20 mg/kg) effectively (P < 0.05) protected against IRI-induced hepatic damage reflected by attenuation of elevated oxidative stress and pro-inflammatory cytokines. Additionally, western blot and ELISA analyses suggested that pinitol significantly (P < 0.05) down-regulated expression of endoplasmic reticulum stress apoptotic markers, namely glucose-regulated protein (GRP)-78, CCAAT/enhancer-binding protein homologous protein (CHOP), activating transcription factor (AFT)-4 and -6α, X-box binding protein-1, and caspase-3, 9, and 12. Additionally, pinitol pre-treatment effectively (P < 0.05) improved mitochondrial function and phosphorylation of Extracellular signal-regulated kinase (ERK)-1/2 and p38. Pinitol markedly (P < 0.05) protected hepatic apoptosis determined by flow cytometry. Further, pinitol provided effective (P < 0.05) protection against hepatic histological and ultrastructural aberrations induced by IRI. TQ showed more pronounced protective effect against attenuation of IRI-induced hepatic injury as compared to d-Pinitol. Pinitol offered protection against endoplasmic reticulum stress-mediated phosphorylation of ERK1/2 and p38, thereby inhibiting AFT4-CHOP/GRP78 signaling response and caspase-3 induced hepatocellular apoptosis during hepatic ischemia-reperfusion insults. Thus, Pinitol can be considered as a viable option for the management of hepatic IRI.

αB-crystallin/HSPB2 is critical for hyperactive mTOR-induced cardiomyopathy.

Even though aberrant mechanistic target of rapamycin (mTOR) signaling is known to cause cardiomyopathy, its underlying mechanism remains poorly understood. Because augmentation of αB-crystallin and hspB2 was presented in the cortical tubers and lymphangioleiomyomatosis of tuberous sclerosis complex patients, we deciphered the role of αB-crystallin and its adjacent duplicate gene, hspB2, in hyperactive mTOR-induced cardiomyopathy. Cardiac Tsc1 deletion (T1-hKO) caused mouse mTOR activation and cardiomyopathy. Overexpression of αB-crystallin and hspB2 was presented in the hearts of these mice. Knockout of αB-crystallin/hspB2 reversed deficient Tsc1-mediated fetal gene expression, mTOR activation, mitochondrial damage, cardiomyocyte vacuolar degeneration, cardiomyocyte size, and fibrosis of T1-hKO mice. These cardiac-Tsc1; αB-crystallin; hspB2 triple knockout (tKO) mice had improved cardiac function, smaller heart weight to body weight ratio, and reduced lethality compared with T1-hKO mice. Even though activated mTOR suppressed autophagy in T1-hKO mice, ablation of αB-crystallin and hspB2 failed to restore autophagy in tKO mice. mTOR inhibitors suppressed αB-crystallin expression in T1-hKO mice and rat cardiomyocyte line H9C2. Starvation of H9C2 cells activated autophagy and suppressed αB-crystallin expression. Since inhibition of autophagy restored αB-crystallin expression in starved H9C2 cells, autophagy is a negative regulator of αB-crystallin expression. mTOR thus stimulates αB-crystallin expression through suppression of autophagy. In conclusion, αB-crystallin and hspB2 play a pivotal role in Tsc1 knockout-related cardiomyopathy and are therapeutic targets of hyperactive mTOR-associated cardiomyopathy.

Synergy of hypoxia relief and heat shock protein inhibition for phototherapy enhancement.

BACKGROUND: Phototherapy is a promising strategy for cancer therapy by reactive oxygen species (ROS) of photodynamic therapy (PDT) and hyperthermia of photothermal therapy (PTT). However, the therapeutic efficacy was restricted by tumor hypoxia and thermal resistance of increased expression of heat shock protein (Hsp). In this study, we developed albumin nanoparticles to combine hypoxia relief and heat shock protein inhibition to overcome these limitations for phototherapy enhancement. RESULTS: Near-infrared photosensitizer (IR780) and gambogic acid (GA, Hsp90 inhibitor) were encapsulated into albumin nanoparticles via hydrophobic interaction, which was further deposited MnO2 on the surface to form IGM nanoparticles. Both in vitro and in vivo studies demonstrated that IGM could catalyze overexpress of hydrogen peroxide to relive hypoxic tumor microenvironment. With near infrared irradiation, the ROS generation was significantly increase for PDT enhancement. In addition, the release of GA was promoted by irradiation to bind with Hsp90, which could reduce cell tolerance to heat for PTT enhancement. As a result, IGM could achieve better antitumor efficacy with enhanced PDT and PTT. CONCLUSION: This study develops a facile approach to co-deliver IR780 and GA with self-assembled albumin nanoparticles, which could relive hypoxia and suppress Hsp for clinical application of cancer phototherapy.

Characterization of the dual functional effects of heat shock proteins (HSPs) in cancer hallmarks to aid development of HSP inhibitors.

BACKGROUND: Heat shock proteins (HSPs), a representative family of chaperone genes, play crucial roles in malignant progression and are pursued as attractive anti-cancer therapeutic targets. Despite tremendous efforts to develop anti-cancer drugs based on HSPs, no HSP inhibitors have thus far reached the milestone of FDA approval. There remains an unmet need to further understand the functional roles of HSPs in cancer. METHODS: We constructed the network for HSPs across ~ 10,000 tumor samples from The Cancer Genome Atlas (TCGA) and ~ 10,000 normal samples from Genotype-Tissue Expression (GTEx), and compared the network disruption between tumor and normal samples. We then examined the associations between HSPs and cancer hallmarks and validated these associations from multiple independent high-throughput functional screens, including Project Achilles and DRIVE. Finally, we experimentally characterized the dual function effects of HSPs in tumor proliferation and metastasis. RESULTS: We comprehensively analyzed the HSP expression landscape across multiple human cancers and revealed a global disruption of the co-expression network for HSPs. Through analyzing HSP expression alteration and its association with tumor proliferation and metastasis, we revealed dual functional effects of HSPs, in that they can simultaneously influence proliferation and metastasis in opposite directions. We experimentally characterized the dual function of two genes, DNAJC9 and HSPA14, in lung cancer cells. We further demonstrated the generalization of this dual direction of associations between HSPs and cancer hallmarks, suggesting the necessity to more carefully evaluate HSPs as therapeutic targets and develop highly specific HSP inhibitors for cancer intervention. CONCLUSIONS: Our study furnishes a holistic view of functional associations of HSPs with cancer hallmarks to aid the development of HSP inhibitors as well as other drugs in cancer therapy.

Over-activation of a nonessential bacterial protease DegP as an antibiotic strategy.

Rising antibiotic resistance urgently begs for novel targets and strategies for antibiotic discovery. Here, we report that over-activation of the periplasmic DegP protease, a member of the highly conserved HtrA family, can be a viable strategy for antibiotic development. We demonstrate that tripodal peptidyl compounds that mimic DegP-activating lipoprotein variants allosterically activate DegP and inhibit the growth of an Escherichia coli strain with a permeable outer membrane in a DegP-dependent fashion. Interestingly, these compounds inhibit bacterial growth at a temperature at which DegP is not essential for cell viability, mainly by over-proteolysis of newly synthesized proteins. Co-crystal structures show that the peptidyl arms of the compounds bind to the substrate-binding sites of DegP. Overall, our results represent an intriguing example of killing bacteria by activating a non-essential enzyme, and thus expand the scope of antibiotic targets beyond the traditional essential proteins or pathways.

Effects of melatonin against thioacetamide-induced testicular toxicity in rats / Efectos de la melatonina contra la toxicidad testicular inducida por tioacetamida en ratas

SUMMARY: This study aimed to investigate the changes in testis tissue of thioacetamide-induced rats and the effect of melatonin on these changes. Thirty-five male Wistar Albino rats were divided into five groups. Group I; Control (n=7), Group II; Melatonin (Mel) (10 mg/kg) a single dose (i.p)(n=7), Group III; Thioacetamide (TAA) (300 mg/kg) (i.p) 2 times with 24 hour intervals (n=7), Group IV; TAA (300 mg/kg) was administered at 24-hour intervals, afterwards of 10 mg/kg single dose of Mel (n=7), Group V; Mel was administered 10 mg/kg a single dose 24 hours before the administration of TAA (n=7). Testis was evaluated histologically, immunohistochemically (Heat Shock Proteins (HSP) 70 and 90), blood serum testosterone, total antioxidant status(TAS) and total oxidant status(TOS) in tissue. The tissue sections of Group III decreased seminiferous tubule diameters, and germinal epithelium spills were observed. HSP70 and HSP90 expressions were increased. There wasn't a statistically significant change in testosterone levels among the groups. While TAS levels decreased in Group III compared to control, TOS levels didn't change. HSP70 and HSP90 decreased in groups with Mel-treated. Mel was found to have both protective and therapeutic effects. According to our results, the therapeutic effect of Mel in thioacetamide-induced acute testicular injury is greater than its protective effect.

RESUMEN: Este estudio tuvo como objetivo investigar los cambios en el tejido testicular de ratas inducidas por tioacetamida y el efecto de la melatonina en estos cambios. Treinta y cinco ratas macho Wistar Albino se dividieron en cinco grupos. Grupo I; Control (n = 7), Grupo II; Melatonina (Mel) (10 mg / kg) una dosis única (i.p) (n = 7), Grupo III; Tioacetamida (TAA) (300 mg / kg) (i.p) 2 veces con intervalos de 24 horas (n = 7), Grupo IV; TAA (300 mg / kg) se administró a intervalos de 24 horas, luego de una dosis única de 10 mg / kg de Mel (n = 7), Grupo V; Mel recibió 10 mg / kg de una dosis única 24 horas antes de la administración de TAA (n = 7). Los testículos se evaluaron histológicamente, inmunohistoquímicamente (proteínas de choque térmico (PCT) 70 y 90), testosterona en suero sanguíneo, estado antioxidante total (EAT) y estado oxidante total (EOT) en el tejido. En secciones de tejido del Grupo III se observó disminución de los diámetros de los túbulos seminíferos y derrames en el epitelio germinal. Se aumentaron las expresiones HSP70 y HSP90. No hubo un cambio estadísticamente significativo en los niveles de testosterona entre los grupos. Mientras que los niveles de EAT disminuyeron en el Grupo III en comparación con el control, los niveles de EOT no cambiaron. HSP70 y HSP90 disminuyeron en los grupos tratados con Mel. Se descubrió que Mel tenía efectos protectores y terapéuticos. Según nuestros resultados, el efecto terapéutico de Mel en la lesión testicular aguda inducida por tioacetamida es mayor que su efecto protector.

Anticancer effect of caudatin in diethylnitrosamine­induced hepatocarcinogenesis in rats.

An overwhelming endoplasmic reticulum stress (ERS) and the following unfolded protein response (UPR) can induce hepatic inflammation, fibrosis and hepatocellular carcinoma (HCC). Caudatin, one of the species of C­21 steroidal glycosides mainly isolated from the roots of Cynanchum bungei Decne, exhibits potent anticancer activities in vivo. However, the effect of caudatin on HCC remains unclear. In the present study, a diethylnitrosamine (DEN)­induced HCC model was established. Nodules and tumors in rat livers were monitored by T2­/T1­weighted­magnetic resonance imaging (MRI) using a 1.5 T scanner. Caudatin reduced the number and size of nodules and alleviated the inflammatory foci in the liver. In addition, the hepatic pro­inflammatory levels of interleukin (IL) 6, monocyte chemoattractant protein 1 and IL­1ß were decreased in caudatin­treated rats. The DEN­induced surge in malondialdehyde, aspartate aminotransferase, alanine transaminase and TBIL were alleviated following caudatin treatment. The expression of ERS chaperones glucose­regulated protein, 94 kDa, glucose­regulated protein, 78 kDa and protein disulfide­isomerase A4 and the proliferation marker Ki­67 in liver nodules were all downregulated by caudatin as demonstrated by immunohistochemistry, reverse transcription­quantitative PCR and western blot analysis. Caudatin reduced the cytoprotective ERS sensor activating transcription factor 6­mediated signal transduction and inhibited the PKR­like endoplasmic reticulum kinase/eukaryotic initiation factor 2α/activating transcription factor 4 pathway. However, the effect of caudatin on inositol requiring enzyme 1 signaling was negligible. In conclusion, restoration of the dysregulated UPR program was involved in the antitumor efficacy of caudatin without inducing cumulative hepatotoxicity.

CXL146, a Novel 4H-Chromene Derivative, Targets GRP78 to Selectively Eliminate Multidrug-Resistant Cancer Cells.

The 78-kDa glucose-regulated protein (GRP78), an endoplasmic reticulum (ER) chaperone, is a master regulator of the ER stress. A number of studies revealed that high levels of GRP78 protein in cancer cells confer multidrug resistance (MDR) to therapeutic treatment. Therefore, drug candidate that reduces GRP78 may represent a novel approach to eliminate MDR cancer cells. Our earlier studies showed that a set of 4H-chromene derivatives induced selective cytotoxicity in MDR cancer cells. In the present study, we elucidated its selective mechanism in four MDR cancer cell lines with one lead candidate (CXL146). Cytotoxicity results confirmed the selective cytotoxicity of CXL146 toward the MDR cancer cell lines. We noted significant overexpression of GRP78 in all four MDR cell lines compared with the parental cell lines. Unexpectedly, CXL146 treatment rapidly and dose-dependently reduced GRP78 protein in MDR cancer cell lines. Using human leukemia (HL) 60/mitoxantrone (MX) 2 cell line as the model, we demonstrated that CXL146 treatment activated the unfolded protein response (UPR); as evidenced by the activation of inositol-requiring enzyme 1α, protein kinase R-like ER kinase, and activating transcription factor 6. CXL146-induced UPR activation led to a series of downstream events, including extracellular signal-regulated kinase 1/2 and c-Jun N-terminal kinase activation, which contributed to CXL146-induced apoptosis. Targeted reduction in GRP78 resulted in reduced sensitivity of HL60/MX2 toward CXL146. Long-term sublethal CXL146 exposure also led to reduction in GRP78 in HL60/MX2. These data collectively support GRP78 as the target of CXL146 in MDR treatment. Interestingly, HL60/MX2 upon long-term sublethal CXL146 exposure regained sensitivity to mitoxantrone treatment. Therefore, further exploration of CXL146 as a novel therapy in treating MDR cancer cells is warranted. SIGNIFICANCE STATEMENT: Multidrug resistance is one major challenge to cancer treatment. This study provides evidence that cancer cells overexpress 78-kDa glucose-regulated protein (GRP78) as a mechanism to acquire resistance to standard cancer therapies. A chromene-based small molecule, CXL146, selectively eliminates cancer cells with GRP78 overexpression via activating unfolded protein response-mediated apoptosis. Further characterization indicates that CXL146 and standard therapies complementarily target different populations of cancer cells, supporting the potential of CXL146 to overcome multidrug resistance in cancer treatment.

Aberrant MUC1 accumulation in salivary glands of Sjögren's syndrome patients is reversed by TUDCA in vitro.

OBJECTIVES: Xerostomia in SS patients has been associated with low quality and quantity of salivary mucins, which are fundamental for the hydration and protection of the oral mucosa. The aim of this study was to evaluate if cytokines induce aberrant mucin expression and whether tauroursodeoxycholic acid (TUDCA) is able to counteract such an anomaly. METHODS: Labial salivary glands from 16 SS patients and 15 control subjects, as well as 3D acini or human submandibular gland cells stimulated with TNF-α or IFN-γ and co-incubated with TUDCA, were analysed. mRNA and protein levels of Mucin 1 (MUC1) and MUC7 were determined by RT-qPCR and western blot, respectively. Co-immunoprecipitation and immunofluorescence assays for mucins and GRP78 [an endoplasmic reticulum (ER)-resident protein] were also performed. mRNA levels of RelA/p65 (nuclear factor-κB subunit), TNF-α, IL-1ß, IL-6, SEL1L and EDEM1 were determined by RT-qPCR, and RelA/p65 localization was evaluated by immunofluorescence. RESULTS: MUC1 is overexpressed and accumulated in the ER of labial salivary gland from SS patients, while MUC7 accumulates throughout the cytoplasm of acinar cells; however, MUC1, but not MUC7, co-precipitated with GRP78. TUDCA diminished the overexpression and aberrant accumulation of MUC1 induced by TNF-α and IFN-γ, as well as the nuclear translocation of RelA/p65, together with the expression of inflammatory and ER stress markers in 3D acini. CONCLUSION: Chronic inflammation alters the secretory process of MUC1, inducing ER stress and affecting the quality of saliva in SS patients. TUDCA showed anti-inflammatory properties decreasing aberrant MUC1 accumulation. Further studies are necessary to evaluate the potential therapeutic effect of TUDCA in restoring glandular homeostasis in SS patients.

Glutamine protects intestine against ischemia-reperfusion injury by alleviating endoplasmic reticulum stress induced apoptosis in rats

Abstract Purpose Glutamine, as an essential part of enteral nutrition and parenteral nutrition agent, has been widely recognized to be a kind of important intestinal mucosa protectant in clinical practice and experimental research. However, the mechanisms of its protective effects are still not fully understand. Consequently, this study aimed to explore the potential mechanism of glutamine on ischemia-reperfusion (I/R) injury induced endoplasmic reticulum (ER) stress in intestine. Methods An experimental model of intestinal I/R in rats was established by 1 hour occlusion of the superior mesenteric artery followed by 3 hours of reperfusion. Morphologic changes of intestinal mucosa, apoptosis of epithelial cells, and expression of intestinal Grp78, Gadd153, Caspase-12, ATF4, PERK phosphorylation (P-PERK) and elF2αphosphorylation(P-elF2α) were determined. Results After I/R, the apoptotic index of intestinal mucosa epithelial cells observably increased with notable necrosis of intestinal mucosa, and the expressions of Grp78, Gadd153, Caspase-12, ATF4, P-PERK and P-elF2αall were increased. However, treatment with glutamine could significantly relieve intestinal I/R injury and apoptosis index. Moreover, glutamine could clearly up-regulate the expression of Grp78, restrain P-PERK and P-elF2α, and reduce ATF4, Gadd153 and Caspase-12 expressions. Conclusion Glutamine may be involved in alleviating ER stress induced intestinal mucosa cells apoptosis.

Heat Shock Proteins in Glioblastoma Biology: Where Do We Stand?

Heat shock proteins (HSPs) are evolutionary conserved proteins that work as molecular chaperones and perform broad and crucial roles in proteostasis, an important process to preserve the integrity of proteins in different cell types, in health and disease. Their function in cancer is an important aspect to be considered for a better understanding of disease development and progression. Glioblastoma (GBM) is the most frequent and lethal brain cancer, with no effective therapies. In recent years, HSPs have been considered as possible targets for GBM therapy due their importance in different mechanisms that govern GBM malignance. In this review, we address current evidence on the role of several HSPs in the biology of GBMs, and how these molecules have been considered in different treatments in the context of this disease, including their activities in glioblastoma stem-like cells (GSCs), a small subpopulation able to drive GBM growth. Additionally, we highlight recent works that approach other classes of chaperones, such as histone and mitochondrial chaperones, as important molecules for GBM aggressiveness. Herein, we provide new insights into how HSPs and their partners play pivotal roles in GBM biology and may open new therapeutic avenues for GBM based on proteostasis machinery.

Sunscreen-induced expression and identification of photosensitive marker proteins in human keratinocytes under UV radiation.

Solar ultraviolet (UV) radiation is the main factor of photocarcinogenesis, photoaging, and photosensitivity; thus protection from biological damaging UV radiation is a concern. Sunscreens containing UV filters are the most preferred means of photoprotection but the safety and efficacy of UV filters are in question. Benzophenone (BP) and its derivatives, namely, benzophenone 1 (BP1), is commonly used in sunscreens as a UV blocker. The aim of this study was to assess the effects of BP and BP1 on the differential expression of proteins in human keratinocytes (HaCaT cells) under exposure to ultraviolet A radiation. Photosensitive proteins were screened from HaCaT cells by two-dimensional (2-D) gel electrophoresis, and identification of these differentially expressed proteins was performed by matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF)/TOF mass spectrometry. Protein identification was performed using the search program MASCOT and a database made of SUMO and GhJMJ12 amino acid sequences. Our results showed that the proteins involved directly or indirectly in apoptosis are 70 kDa heat shock protein, long-chain specific acyl-CoA dehydrogenase, serine/threonine-protein kinase, and FAM78A protein, which were upregulated in comparison to control HaCaT cells. The expressions of binding immunoglobulin protein, podocalyxin-like protein, actin, cytoplasmic, and calreticulin precursors were downregulated. The altered protein expression indicated that cell growth arrest and apoptosis were potential mechanisms of cytotoxicity and genotoxicity of BPs. The results of 2-D gel electrophoresis followed by mass spectrometry showed expression of novel proteins involved in promoting or initiating apoptotic pathways. Hence, we conclude that BPs should be avoided as a UV blocker from sunscreens because of its potential to promote apoptotic proteins in human skin keratinocytes.

In Vitro and In Vivo Renoprotective Effects of Telbivudine in Chronic Hepatitis B Patients Receiving Nucleotide Analogue.

AIM: Renal toxicity of adefovir disoproxil (ADV) and tenofovir disoproxil fumarate (TDF) is a significant concern in chronic hepatitis B (CHB) patients. Early observational clinical data suggested that telbivudine (LdT) might have renoprotective effects. METHODS: In this prospective study, consecutive CHB patients on combined lamivudine (LAM) + ADV/TDF were switched to LdT + ADV/TDF at recruitment and were followed up for 24 months. Estimated glomerular filtration rate (eGFR) was calculated with the modification of diet in renal disease equation. The effects of LdT on cell viability and expression of kidney injury or apoptotic biomarkers were investigated in cultured renal tubular epithelial cell line HK-2. RESULTS: Thirty-one patients (median age 55 years, 90.3% male) were recruited (54.8% TDF: 45.2% ADV). Serum HBV DNA was undetectable at all time points. Median eGFR was 70.2 (IQR 62.6-77.9) and 81.5 (IQR 63.6-99.1) mL/min/1.73 m2 at baseline and 24 months, respectively (p < 0.001). Downstaging of chronic kidney disease was observed in eight (25.8%) patients and was more common in ADV-treated compared to TDF-treated patients (7/8 vs. 1/17, p = 0.011; OR 16, 95% CI 1.643-155.766, p = 0.017). In vitro data showed that adding LdT to ADV or TDF was associated with improved cell viability and lower expression of injury and apoptotic biomarkers compared with ADV or TDF alone. Treatment was prematurely discontinued in four(12.9%) patients due to myalgia. CONCLUSIONS: Clinical and in vitro data suggest that LdT has renoprotective effects in patients on long-term ADV/TDF treatment. LdT may be considered as an adjuvant therapy in this special group of patients with renal impairment (NCT03778567).

Inhibition of SIRT1/2 upregulates HSPA5 acetylation and induces pro-survival autophagy via ATF4-DDIT4-mTORC1 axis in human lung cancer cells.

Sirtuins have emerged as a promising novel class of anti-cancer drug targets. Inhibition of SIRT1 and SIRT2 induces apoptosis in cancer cells and they play multifaceted roles in regulating autophagy. In the present study, we found that salermide, a SIRT1/2-specific inhibitor or small interfering RNAs (siRNAs) to block SIRT1/2 expression could induce autophagy in human NSCLC cells. Moreover, SIRT1/2 inhibition increased the expression levels of ATF4 and DDIT4 and downregulated p-RPS6KB1 and p-EIF4EBP1, two downstream molecules of mTORC1. Moreover, ATF4 or DDIT4 knockdown attenuated salermide-induced autophagy, suggesting that SIRT1/2 inhibition induced autophagy through the ATF4-DDIT4-mTORC1 axis. Mechanistically, SIRT1/2 inhibition led to HSPA5 acetylation and dissociation from EIF2AK3, leading to ER stress response and followed by upregulation of ATF4 and DDIT4, triggering autophagy. Silencing of the autophagic gene ATG5 in lung cancer cells resulted in increased apoptotic cell death induced by SIRT1/2 inhibition. Our data show that inhibition of SIRT1/2 induces pro-survival autophagy via acetylation of HSPA5 and subsequent activation of ATF4 and DDIT4 to inhibit the mTOR signaling pathway in NSCLC cells. These findings suggest that combinatorial treatment with SIRT1/2 inhibitors and pharmacological autophagy inhibitors is an effective therapeutic strategy for cancer therapy.

(-)-Epigallocatechin Gallate (EGCG) Enhances the Sensitivity of Colorectal Cancer Cells to 5-FU by Inhibiting GRP78/NF-κB/miR-155-5p/MDR1 Pathway.

Green tea accounts for approximately 20% of the world's total tea yield. (-)-Epigallocatechin gallate (EGCG) is an active catechin in green tea, which suppresses tumor growth and enhances drug sensitivity in various cancers, but the molecular mechanism is still unclear. Chemotherapy drugs, such as 5-fluorouracil (5-FU), are a common strategy for clinical treatment of cancer patients; however, the lower response rate caused by prolonged use becomes the main reason for tumor recurrence. Therefore, discovering a safe and effective chemo-sensitizer is an urgent task required to be solved. Here, we report that EGCG reinforces the sensitivity of colon cancer cells to 5-FU, and the IC50 values of 5-FU is decreased from 40 ± 4.2 µM to 5 ± 0.36 µM in one human colon carcinoma cell line-HCT-116, and from 150 ± 6.4 µM to 11 ± 0.96 µM in the other human colon carcinoma cell line-DLD1 when these cells are cotreated with 50 µM EGCG. Consistently, compared to 5-FU or EGCG treatment alone, the combination of both significantly promotes cancer cell apoptosis and DNA damage. Further mechanism research reveals that treatment of colorectal cancer (CRC) with 50 µM EGCG inhibits GRP78 expression, activates the NF-κB (2.55 ± 0.05-fold for HCT-116 and 2.27 ± 0.08-fold for DLD1) pathway, and enhances miR-155-5p (2.12 ± 0.02-fold for HCT-116 and 2.01 ± 0.01-fold for DLD1) level. The elevated miR-155-5p strongly suppresses target gene MDR1 expression, which blocks the efflux of 5-FU. The accumulation of 5-FU resulted in caspase-3 and PARP activation, Bcl-2 reduction, and Bad increase, which ultimately lead to cancer cell apoptosis. Overall, our data show that EGCG may be act as a novel chemo-sensitizer, and the GRP78/NF-κB/miR-155-5p/MDR1 pathway plays a vital role in EGCG enhancing the sensitivity of colorectal cancer to 5-FU.

Glucose-regulated protein 78 in the aqueous humor in diabetic macular edema patients.

In this study, we explored the presence and elevation of glucose-regulated protein 78 (GRP78) in aqueous humor of patients with diabetic macular edema (DME).After comparing DME patients with the controls, we analyzed GRP78 and vascular endothelial growth factor (VEGF) levels in DME patients. We examined factors associated with GRP78 levels in DME patients.GRP78 was detected in aqueous humor with elevated levels in DME patients. Stepwise backward regression analysis showed that GRP78 levels were associated with the VEGF levels and the duration of diabetes (P < .001 and P = .002, respectively). However, no statistical significance was observed between GRP78 levels and the decrease in CST following 3 monthly anti-VEGF treatments in univariate regression analysis (P = .695).We showed that GRP78 is elevated in DME patients. In addition, there is a correlation between GRP78 and VEGF levels in aqueous humor. However, GRP78 levels were not associated with the responsiveness of anti-VEGF in DME patients.

Chinese Herbal Medicine Effects on Muscle Atrophy Induced by Simulated Microgravity.

BACKGROUND: Skeletal muscle atrophy is a striking example of the multiple changes in the physiological state of humans and animals induced by microgravity. Previous studies have shown that a blood circulation disorder may be a cause of this atrophy, and traditional Chinese medicine has been regarded as a potential countermeasure to reverse the atrophy in China. This study was carried out to test the effects of Xuefuzhuyu capsules (XFZY) on the skeletal muscle atrophy induced by simulated microgravity. METHODS: The mass and cross-sectional area of the soleus muscle were compared in rats treated with XFZY that were hindlimb unloaded for 30 d (XFZY-TS group), untreated rats that were hindlimb unloaded for 30 d (TS group), and control rats (CON group). The expression and phosphorylation levels of key proteins of the sarcoplasmic reticulum stress system were also measured. RESULTS: Treatment with XFZY attenuated the loss of muscle mass and cross-sectional area induced by hindlimb unloading. Western blot analysis showed that the phosphatidyl-inositol-3-kinase/phospho-Akt (PI3K/p-Akt) pathways were down-regulated after 30 d in the TS group compared with the CON group. This effect was partly reversed by XFZY. Hindlimb unloading increased the expression of glucose-regulated protein 78 (GRP78), cytosine-cytosine-adenosine-adenosine-thymidine/enhancer-binding protein homologous protein (CHOP), C-Jun N-terminal kinase (JNK), and Caspase 12. Treatment with XFZY alleviated this increased protein expression. DISCUSSION: Our results suggest that XFZY could partially reverse the effects of hindlimb unloading on muscle atrophy and perhaps target the sarcoplasmic reticulum stress system, possibly through the GRP78-CHOP-JNK-Caspase 12 pathway.Zhang S, Yuan M, Cheng C, Xia D, Wu S. Chinese herbal medicine effects on muscle atrophy induced by simulated microgravity. Aerosp Med Hum Perform. 2018; 89(10):883-888.

Modulation of Heat Shock Response Proteins by ASS234, Targeted for Neurodegenerative Diseases Therapy.

ASS234 is a new multitarget molecule with multiple neuroprotective actions that significantly elevate mRNA levels of NRF2 and HSF1 transcriptional factors and of HSP105, HSP90AB1, HSPA1A, HSPA1B, HSPA5, HSPA8, HSPA9, HSP60, DNAJA1, DNAJB1, DNAJB6, DNAJC3, DNAJC5, DNAJC6, HSPB1, HSPB2, HSPB5, HSPB6, HSPB8, and HSP10 heat shock proteins (HSPs) family members in SH-SY5Y cells. This NRF2 and HSF1 overexpression may explain the upregulation of both the antioxidant enzymes previously described and the members of the HSPs family observed. These findings suggest that ASS234 is a potent HSPs inductor, which might be beneficial for preventing protein misfolding aggregation and cell death in Alzheimer's disease and other neurodegenerative diseases.

The small heat shock proteins, especially HspB4 and HspB5 are promising protectants in neurodegenerative diseases.

Small heat shock proteins (sHsps) are a group of proteins with molecular mass between 12 and 43 kDa. Currently, 11 members of this family have been classified, namely HspB1 to HspB11. HspB1, HspB2, HspB5, HspB6, HspB7, and HspB8, which are expressed in brain have been observed to be related to the pathology of neurodegenerative diseases, including Parkinson's, Alzheimer's, Alexander's disease, multiple sclerosis, and human immunodeficiency virus-associated dementia. Specifically, sHsps interact with misfolding and damaging protein aggregates, like Glial fibrillary acidic protein in AxD, ß-amyloid peptides aggregates in Alzheimer's disease, Superoxide dismutase 1 in Amyotrophic lateral sclerosis and cytosine-adenine-guanine/polyglutamine (CAG/PolyQ) in Huntington's disease, Spinocerebellar ataxia type 3, Spinal-bulbar muscular atrophy, to reduce the toxicity or increase the clearance of these protein aggregates. The degree of HspB4 expression in brain is still debated. For neuroprotective mechanisms, sHsps attenuate mitochondrial dysfunctions, reduce accumulation of misfolded proteins, block oxidative/nitrosative stress, and minimize neuronal apoptosis and neuroinflammation, which are molecular mechanisms commonly accepted to mirror the progression and development of neurodegenerative diseases. The increasing incidence of the neurodegenerative diseases enhanced search for effective approaches to rescue neural tissue from degeneration with minimal side effects. sHsps have been found to exert neuroprotective functions. HspB5 has been emphasized to reduce the paralysis in a mouse model of experimental autoimmune encephalomyelitis, providing a therapeutic basis for the disease. In this review, we discuss the current understanding of the properties and the mechanisms of protection orchestrated by sHsps in the nervous system, highlighting the promising therapeutic role of sHsps in neurodegenerative diseases.

MAPK pathway regulated the cardiomyocyte apoptosis in mice with post-infarction heart failure.

BACKGROUND: To explore the role of the MAPK signaling pathway in the cardiomyocyte apoptosis of mice with post-infarction heart failure (HF). METHODS: Mice were divided into sham and myocardial infarction (MI) groups. Before surgery, the MI group was divided into SB203580 and PBS subgroups. A post-infarction HF model was established by ligating the left anterior descending coronary artery. Ventricular dilatation and cardiac function were observed by small animal echocardiography. The growth of primary cardiomyocytes was observed under an inverted phase contrast microscope. The mRNA and protein expressions of endoplasmic reticulum stress (ERS) markers, GRP78 and CHOP, were detected by qRT-PCR and immunofluorescence assay, respectively. RESULTS: The MI group had enlarged left ventricle and decreased cardiac function. GRP78 and CHOP protein expressions in myocardial tissues, especially those of SB203580 subgroup, significantly increased (p < 0.05). The expressions of p-JNK and cleaved caspase 12 proteins, especially those of SB203580 subgroup, were significantly up-regulated. Cardiomyocytes of MI group were significantly more prone to apoptosis (p < 0.05), with SB203580 subgroup being more obvious. CONCLUSION: MI was accompanied by ERS, probably involving the MAPK signaling pathway. SB203580, a specific inhibitor of this pathway, can relieve cardiomyocyte apoptosis and protect the myocardium by suppressing such stress (Tab. 3, Fig. 7, Ref. 20).