Growth differentiation factor 15 induces cisplatin resistance through upregulation of xCT expression and glutathione synthesis in gastric cancer.

Gastric cancer is a common cancer worldwide, particularly in East Asia. Chemotherapy is used in adjuvant or palliative therapies for gastric cancer. However, subsequent chemoresistance often develops. Growth differentiation factor 15 (GDF15) links to several cancers, but its effect on chemoresistance in gastric cancer remains unclear. Here, we analyzed clinical samples from genetic databases and included patients with gastric cancer. We dissected the regulatory mechanism underlying GDF15-mediated resistance of cisplatin in human gastric cancer cells. We showed that GDF15 serum levels might be a valuable biomarker for predicting prognosis in gastric cancer. The expressions of GDF15 and its receptor glial cell-derived neurotrophic factor family receptor a-like (GFRAL) in gastric tumors are important for malignant progression. Moreover, GDF15 expression is increased in gastric cancer cells with cisplatin resistance, resulting from elevated intracellular glutathione (GSH) and antioxidant activities. Upregulated GDF15 could increase intracellular GSH content by activating the GFRAL-GCN2-eIF2α-ATF4 signaling, enhancing cystine-uptake transporter xCT expression, and contributing biosynthesis of GSH in human gastric cancer cells. In conclusion, our results indicate that GDF15 could induce chemoresistance by upregulating xCT expression and GSH biosynthesis in human gastric cancer cells. Targeting GDF15 could be a promising treatment method for gastric cancer progression.

Role of mitochondrial alterations in human cancer progression and cancer immunity.

Dysregulating cellular metabolism is one of the emerging cancer hallmarks. Mitochondria are essential organelles responsible for numerous physiologic processes, such as energy production, cellular metabolism, apoptosis, and calcium and redox homeostasis. Although the "Warburg effect," in which cancer cells prefer aerobic glycolysis even under normal oxygen circumstances, was proposed a century ago, how mitochondrial dysfunction contributes to cancer progression is still unclear. This review discusses recent progress in the alterations of mitochondrial DNA (mtDNA) and mitochondrial dynamics in cancer malignant progression. Moreover, we integrate the possible regulatory mechanism of mitochondrial dysfunction-mediated mitochondrial retrograde signaling pathways, including mitochondrion-derived molecules (reactive oxygen species, calcium, oncometabolites, and mtDNA) and mitochondrial stress response pathways (mitochondrial unfolded protein response and integrated stress response) in cancer progression and provide the possible therapeutic targets. Furthermore, we discuss recent findings on the role of mitochondria in the immune regulatory function of immune cells and reveal the impact of the tumor microenvironment and metabolism remodeling on cancer immunity. Targeting the mitochondria and metabolism might improve cancer immunotherapy. These findings suggest that targeting mitochondrial retrograde signaling in cancer malignancy and modulating metabolism and mitochondria in cancer immunity might be promising treatment strategies for cancer patients and provide precise and personalized medicine against cancer.

Circulating microRNAs Associated With Reversible Cerebral Vasoconstriction Syndrome.

OBJECTIVE: The purpose of this study was to investigate the significance of circulating micro RNAs (miRNAs) in the pathogenesis of reversible cerebral vasoconstriction syndrome (RCVS). METHODS: We prospectively recruited 3 independent cohorts of patients with RCVS and age-matched and sex-matched controls in a single medical center. Next-generation small RNA sequencing followed by quantitative polymerase chain reaction (PCR) was used to identify and validate differentially expressed miRNAs, which was cross-validated in migraine patients in ictal stage or interictal stage. Computational analysis was used to predict the target genes of miRNAs, followed by in vitro functional analysis. RESULTS: We identified a panel of miRNAs including miR-130a-3p, miR-130b-3p, let-7a-5p, let-7b-5p, and let-7f-5p that well differentiated patients with RCVS from controls (area under the receiver operating characteristics curve [AUC] was 0.906, 0.890, and 0.867 in the 3 cohorts, respectively). The abundance of let-7a-5p, let-7b-5p, and let-7f-5p, but not miR-130a-3p nor miR-130b-3p, was significantly higher in patients with ictal migraine compared with that of controls and patients with interictal migraine. Target prediction and pathway enrichment analysis suggested that the transforming growth factor-ß signaling pathway and endothelin-1 responsible for vasomotor control might link these miRNAs to RCVS pathogenesis, which was confirmed in vitro by transfecting miRNAs mimics or incubating the patients' cerebrospinal fluid (CSF) in 3 different vascular endothelial cells. Moreover, miR-130a-3p was associated with imaging-proven disruption of the blood-brain barrier (BBB) in patients with RCVS and its overexpression led to reduced transendothelial electrical resistance (ie, increased permeability) in in vitro human BBB model. INTERPRETATION: We identified the circulating miRNA signatures associated with RCVS, which may be functionally linked to its headache, BBB integrity, and vasomotor function. ANN NEUROL 2021;89:459-473.

Faculty appointment and promotion in Taiwan's medical schools, a systematic analysis.

BACKGROUND: A rigorous faculty appointment and promotion (FAP) system is vital for the success of any academic institution. However, studies examining the FAP system in Asian universities are lacking. We surveyed the FAP policies of Taiwan's medical schools and identified an overreliance on the CJA score (manuscript Category, Journal quality, and Author order). The potential shortcomings of this metric and recommendations for refinement were discussed. METHODS: We obtained the FAP documents from all 12 medical schools in Taiwan, and analyzed their use of traditional versus non-traditional criteria for FAP according to a published methodology. The influence of the journal impact factor (JIF) on the FAP process was quantified by comparing its relative weight between papers with two extreme JIFs. To better understand the research impact and international standing of each school, we utilized the public bibliographic database to rank universities by the number of papers, and the proportions of papers within the top 10% or 50% citation. RESULTS: Compared with other countries, Taiwan's medical schools focus more on the quantifiable quality of the research, mostly using a "CJA" score that integrates the category, JIF or ranking, and authorship of a paper, with the JIF being the most influential factor. The CJA score for an article with a JIF of 20 can be up to three times the threshold for promotion to Assistant Professor. The emphasis on JIF is based on a presumed correlation between JIF and citation counts. However, our analysis shows that Taiwan's medical schools have lower-than-average citation counts despite a competitive rank in the number of publications. CONCLUSIONS: The JIF plays an unrivaled role in determining the outcome of FAP in Taiwan's medical schools, mostly via the CJA system. The questionable effectiveness of the current system in elevating the international standing of Taiwan's higher-education institutions calls for a re-examination of the FAP system. We recommend a reduction in the relative importance of CJA score in the FAP system, adopting more rigorous metrics such as the h-index for evaluating research quality, and supporting more research aimed at improving the FAP system.

Ash2l interacts with Oct4-stemness circuitry to promote super-enhancer-driven pluripotency network.

Pluripotency and cell fates can be modulated through the regulation of super-enhancers; however, the underlying mechanisms are unclear. Here, we showed a novel mechanism in which Ash2l directly binds to super-enhancers of several stemness genes to regulate pluripotency and self-renewal in pluripotent stem cells. Ash2l recruits Oct4/Sox2/Nanog (OSN) to form Ash2l/OSN complex at the super-enhancers of Jarid2, Nanog, Sox2 and Oct4, and further drives enhancer activation, upregulation of stemness genes, and maintains the pluripotent circuitry. Ash2l knockdown abrogates the OSN recruitment to all super-enhancers and further hinders the enhancer activation. In addition, CRISPRi/dCas9-mediated blocking of Ash2l-binding motifs at these super-enhancers also prevents OSN recruitment and enhancer activation, validating that Ash2l directly binds to super-enhancers and initiates the pluripotency network. Transfection of Ash2l with W118A mutation to disrupt Ash2l-Oct4 interaction fails to rescue Ash2l-driven enhancer activation and pluripotent gene upregulation in Ash2l-depleted pluripotent stem cells. Together, our data demonstrated Ash2l formed an enhancer-bound Ash2l/OSN complex that can drive enhancer activation, govern pluripotency network and stemness circuitry.

Printing a Three-Dimensional Patient-Specific Safety Device for Reducing the Potential Risk of Mental Nerve Injury During Transoral Thyroidectomy.

BACKGROUND: Thyroidectomy transoral endoscopic thyroidectomy vestibular approach (TOETVA) is a safe and cosmetically appealing alternative for well-selected patients undergoing thyroidectomy. However, during TOETVA, placement of the two lateral trocars and/or manipulation of the surgical instruments through the trocars may potentially injure and/or compress the mental nerve (MN) because the actual location of the nerve foramen may vary among individuals. The MN injury rate was reported to be as high as 75% in the initial period of robotic-assisted TOETVA. To reduce the potential risk of MN injury, we implemented a three-dimensional printing technology to develop a safety device for TOETVA. METHODS: The patient-specific safety device (PSSD) was a brace with an exact fit to the lower teeth and two safety markers on each side to indicate the location of the mental foramen. For patient in whom the brace would not be applicable, a 3D mandibular model was printed as a PSSD instead. We analyzed 66 patients undergoing TOETVA at our institution from March 2017 to March 2019. The preoperative details and complication profiles were also analyzed. RESULTS: With incorporation of the PSSD into our TOETVA procedure, there have been no cases of MN injury. CONCLUSIONS: Our own TOETVA series has demonstrated that the implementation of the PSSD has been successful in preoperatively identifying and preventing the potential risk of MN injury. Although the additional requirements of preoperative CT and time for fabricating the device impose limitations, the influence of the PSSD in TOETVA is positive.

Bioactivity and gene expression profiles of hiPSC-generated retinal ganglion cells in MT-ND4 mutated Leber's hereditary optic neuropathy.

Leber's hereditary optic neuropathy (LHON) is the maternally inherited mitochondrial disease caused by homoplasmic mutations in mitochondrial electron transport chain Complex I subunit genes. The mechanism of its incomplete penetrance is still largely unclear. In this study, we created the patient-specific human induced pluripotent stem cells (hiPSCs) from MT-ND4 mutated LHON-affected patient, asymptomatic mutation carrier and healthy control, and differentiated them into retinal ganglion cells (RGCs). We found the defective neurite outgrowth in affected RGCs, but not in the carrier RGCs which had significant expression of SNCG gene. We observed enhanced mitochondrial biogenesis in affected and carrier derived RGCs. Surprisingly, we observed increased NADH dehydrogenase enzymatic activity of Complex I in hiPSC-derived RGCs of asymptomatic carrier, but not of the affected patient. LHON mutation substantially decreased basal respiration in both affected and unaffected carrier hiPSCs, and had the same effect on spare respiratory capacity, which ensures normal function of mitochondria in conditions of increased energy demand or environmental stress. The expression of antioxidant enzyme catalase was decreased in affected and carrier patient hiPSC-derived RGCs as compared to the healthy control, which might indicate to higher oxidative stress-enriched environment in the LHON-specific RGCs. Microarray profiling demonstrated enhanced expression of cell cycle machinery and downregulation of neuronal specific genes.

Activated Integrated Stress Response Induced by Salubrinal Promotes Cisplatin Resistance in Human Gastric Cancer Cells via Enhanced xCT Expression and Glutathione Biosynthesis.

The integrated stress response (ISR) pathway is essential for adaption of various stresses and is related to mitochondrion-to-nucleus communication. Mitochondrial dysfunction-induced reactive oxygen species (ROS) was demonstrated to activate general control nonderepressible 2 (GCN2)⁻eukaryotic translation initiation factor 2α (eIF2α)⁻activating transcription factor-4 (ATF4) pathway-mediated cisplatin resistance of human gastric cancer cells. However, whether or how ISR activation per se could enhance chemoresistance remains unclear. In this study, we used eIF2α phosphatase inhibitor salubrinal to activate the ISR pathway and found that salubrinal reduced susceptibility to cisplatin. Moreover, salubrinal up-regulated ATF4-modulated gene expression, and knockdown of ATF4 attenuated salubrinal-induced drug resistance, suggesting that ATF4-modulated genes contribute to the process. The ATF4-modulated genes, xCT (a cystine/glutamate anti-transporter), tribbles-related protein 3 (TRB3), heme oxygenase 1 (HO-1), and phosphoenolpyruvate carboxykinase 2 (PCK2), were associated with a poorer prognosis for gastric cancer patients. By silencing individual genes, we found that xCT, but not TRB3, HO-1, or PCK2, is responsible for salubrinal-induced cisplatin resistance. In addition, salubrinal increased intracellular glutathione (GSH) and decreased cisplatin-induced lipid peroxidation. Salubrinal-induced cisplatin resistance was attenuated by inhibition of xCT and GSH biosynthesis. In conclusion, our results suggest that ISR activation by salubrinal up-regulates ATF4-modulated gene expression, increases GSH synthesis, and decreases cisplatin-induced oxidative damage, which contribute to cisplatin resistance in gastric cancer cells.

Peroxisome Proliferator-Activated Receptor γ Expression Is Inversely Associated with Macroscopic Vascular Invasion in Human Hepatocellular Carcinoma.

Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated nuclear receptor that regulates cellular lipid and glucose metabolism and also plays an inhibitory role in various cancers. However, the role of PPARγ in hepatocellular carcinoma (HCC) remains controversial. This study aimed to investigate the prognostic value of PPARγ in HCC and its role in inhibiting tumor progression, namely, HCC cell growth, migration, and angiogenesis. Immunohistochemical PPARγ staining was examined in 83 HCC specimens to investigate the clinicopathological correlations between PPARγ expression and various parameters. The functional role of PPARγ was determined via PPARγ overexpression and knockdown in HCC cells. Patients with low HCC tissue PPARγ expression were significantly younger (p = 0.006), and exhibited more tumor numbers (p = 0.038), more macroscopic vascular invasion (MVI) (p = 0.008), and more advanced TNM (size of primary tumor, number of regional lymph nodes, and distant metastasis) stages at diagnosis (p = 0.013) than patients with high HCC tissue PPARγ expression. PPARγ knockdown increased HCC cell growth, migration, and angiogenesis, while PPARγ overexpression reduced HCC cell growth, migration, and angiogenesis. These results suggest that low PPARγ expression is an independent predictor of more MVI in HCC patients. PPARγ contributes to the suppression of HCC cell growth, migration, and angiogenesis. Therefore, PPARγ may be a therapeutic target in HCC patients.

Functional dysconnection in the prefrontal-amygdala circuitry in unaffected siblings of patients with bipolar I disorder.

OBJECTIVES: Bipolar I disorder (BD) is a highly heritable disorder characterized by mood swings between high-energy and low-energy states. Amygdala hyperactivity and cortical inhibitory hypoactivity [e.g., of the dorsolateral prefrontal cortex (dlPFC)] have been found in patients with BD, as evidenced by their abnormal resting-state functional connectivity (FC) and glucose utilization (GU). However, it has not been determined whether functional abnormalities of the dlPFC-amygdala circuit exist in unaffected, healthy siblings of the patients with BD (BDsib). METHODS: Twenty euthymic patients with BD, 20 unaffected matching BDsib of the patient group, and 20 well-matched healthy control subjects were recruited. We investigated seed-based FC (seeds: dlPFC) with resting-state functional magnetic resonance imaging and GU in the regions of interest (e.g., dlPFC and amygdala) using (18) F-fluorodeoxyglucose positron emission tomography. RESULTS: The FC in the dlPFC (right)-amygdala circuit was statistically abnormal in patients with BD and BDsib, but only the patients with BD demonstrated hypoactive GU bilaterally in the dlPFC and hyperactive GU bilaterally in the amygdala. Facilitating differentiation between the BD groups, the altered FC between dlPFC (right) and amygdala (left) was even more prominent in the patients with BD (p < 0.05). CONCLUSIONS: There was a dysfunctional connection with intact GU in the dlPFC-amygdala circuit of the BDsib, which highlights the vulnerability in families with BD. Diminished top-down control from the bilateral dlPFC, which prevents adequate inhibition of limbic hyperactivity, might mediate the development of BD.

Downregulation of tumor suppressor MBP-1 by microRNA-363 in gastric carcinogenesis.

Gastric carcinoma is one of the most common malignancies and the second most lethal cancer worldwide. The mechanisms underlying aggressiveness of gastric cancer still remain obscure. c-Myc promoter binding protein 1 (MBP-1) is a negative regulator of c-myc expression and ubiquitously expressed in normal human tissues. It is produced by alternative translation initiation of α-enolase gene. Both MBP-1 and α-enolase are involved in the control of tumorigenesis including gastric cancer. MicroRNAs (miRNAs) are involved in tumorigenesis and could have diagnostic, prognostic and therapeutic potential. In this study, whether miRNAs modulate tumorigenesis of gastric cancer cells through targeting MBP-1 was evaluated. We found that miR-363 targets 3'-untranslated region of human MBP-1/α-enolase messenger RNA. The exogenous miR-363 promotes growth, viability, progression, epithelial-mesenchymal transition and tumorsphere formation of SC-M1 gastric cancer cells through downregulation of MBP-1, whereas the knockdown of endogenous miR-363 suppresses tumorigenesis and progression of SC-M1 cells via upregulation of MBP-1. The miR-363/MBP-1 axis is also involved in the control of carcinogenesis in KATO III and SNU-16 gastric cancer cells. Furthermore, miR-363 induces the xenografted tumor growth and lung metastasis of SC-M1 cells through MBP-1 in vivo. Taken together, these results suggest that miR-363 plays an important role in the increment of gastric carcinogenesis via targeting MBP-1.

Regulation of mitochondrial F(o)F(1)ATPase activity by Sirt3-catalyzed deacetylation and its deficiency in human cells harboring 4977bp deletion of mitochondrial DNA.

Sirt3, a mitochondrial NAD(+)-dependent deacetylase, is regarded as a potential regulator in cellular metabolism. However, the role of Sirt3 in the regulation of mitochondrial F(o)F(1)ATPase and the linkage to mitochondrial diseases is unclear. In this study, we demonstrated a role of Sirt3 in the regulation of F(o)F(1)ATPase activity in human cells. Knockdown of Sirt3 in 143B cells by shRNA transfection caused increased acetylation levels of the α and OSCP subunits of F(o)F(1)ATPase. We showed that Sirt3 physically interacted with the OSCP and led to its subsequent deacetylation. By incubation of mitochondria with the purified Sirt3 protein, Sirt3 could regulate F(o)F(1)ATPase activity through its deacetylase activity. Moreover, suppression of Sirt3 reduced the F(o)F(1)ATPase activity, consequently decreased the intracellular ATP level, diminished the capacity of mitochondrial respiration, and compromised metabolic adaptability of 143B cells to the use of galactose as the energy source. In human cells harboring ≅85% of mtDNA with 4977bp deletion, we showed that oxidative stress induced a reduction of Sirt3 expression, and an increased acetylation of the OSCP subunit of F(o)F(1)ATPase. Importantly, the expression of Sirt3 was also decreased in the skin fibroblasts from patients with CPEO syndrome. We further demonstrated that oxidative stress induced by 5-10µM of menadione impaired the Sirt3-mediated deacetylation and activation on F(o)F(1)ATPase activity through decreasing the protein level of Sirt3. Our findings suggest that increased intracellular ROS levels might modulate the expression of Sirt3 which deacetylates and activates F(o)F(1)ATPase in human cells with mitochondrial dysfunction caused by a pathogenic mtDNA mutation.

Mitochondrial dysfunction represses HIF-1α protein synthesis through AMPK activation in human hepatoma HepG2 cells.

BACKGROUND: Hypoxia-inducible factor-1α (HIF-1α) is an important transcription factor that modulates cellular responses to hypoxia and also plays critical roles in cancer progression. Recently, somatic mutations and decreased copy number of mitochondrial DNA (mtDNA) were detected in hepatocellular carcinoma (HCC). These mutations were shown to have the potential to cause mitochondrial dysfunction. However, the effects and mechanisms of mitochondrial dysfunction on HIF-1α function are not fully understood. This study aims to explore the underlying mechanism by which mitochondrial dysfunction regulates HIF-1α expression. METHODS: Human hepatoma HepG2 cells were treated with various mitochondrial respiration inhibitors and an uncoupler, respectively, and the mRNA and protein expressions as well as transactivation activity of HIF-1α were determined. The role of AMP-activated protein kinase (AMPK) was further analyzed by compound C and AMPK knock-down. RESULTS: Treatments of mitochondrial inhibitors and an uncoupler respectively reduced both the protein level and transactivation activity of HIF-1α in HepG2 cells under normoxia or hypoxia. The mitochondrial dysfunction-repressed HIF-1α protein synthesis was associated with decreased phosphorylations of p70(S6K) and 4E-BP-1. Moreover, mitochondrial dysfunction decreased intracellular ATP content and elevated the phosphorylation of AMPK. Treatments with compound C, an AMPK inhibitor, and knock-down of AMPK partially rescued the mitochondrial dysfunction-repressed HIF-1α expression. CONCLUSIONS: Mitochondrial dysfunctions resulted in reduced HIF-1α protein synthesis through AMPK-dependent manner in HepG2 cells. GENERAL SIGNIFICANCE: Our results provided a mechanism for communication from mitochondria to the nucleus through AMPK-HIF-1α. Mitochondrial function is important for HIF-1α expression in cancer progression.

SIRT3 expression as a biomarker for better prognosis in gastric cancer.

BACKGROUND: SIRT3-mitochondrial nicotinamide adenine dinucleotide-dependent deacetylase sirtuin-3-plays an important role in regulating cell metabolism and carcinogenesis. The role of SIRT3 in gastric cancer has not yet been investigated. METHODS: A total of 221 gastric cancer patients who underwent curative surgery were enrolled at the Department of Surgery, Taipei Veterans General Hospital. SIRT3 expression in gastric tissues and tumors were examined in these patients using immunohistochemical staining. Clinicopathologic characteristics and survival were analyzed and compared in gastric cancer patients with or without SIRT3 expression. RESULTS: The 5-year survival rates of patients with or without SIRT3 expression were 51.2 and 39.1 %, respectively (p = 0.005). The 5-year disease-free survival rates of patients with or without SIRT3 expression were 49.6 and 38.0 %, respectively (p = 0.010). Microscopic features showed that there are more poor cell differentiation (p = 0.001), more diffuse-type Lauren's histology (p = 0.018), and more scirrhous-type stromal reactions (p = 0.027) in gastric cancer without SIRT expression. Multivariate analysis with overall survival as an endpoint showed that age (p < 0.001), Lauren's histology (p = 0.007), stromal reaction (p = 0.035), TNM pathologic N category (p < 0.001), and SIRT3 expression (p < 0.001) were significantly correlated with gastric cancer. CONCLUSIONS: Gastric cancer patients with SIRT3 expression have a better prognosis than those without. SIRT3 expression is an independent prognostic marker for overall survival and may act as a tumor suppressor in gastric cancer.

Mitochondrial dysfunction decreases cisplatin sensitivity in gastric cancer cells through upregulation of integrated stress response and mitokine GDF15.

Gastric neoplasm is a high-mortality cancer worldwide. Chemoresistance is the obstacle against gastric cancer treatment. Mitochondrial dysfunction has been observed to promote malignant progression. However, the underlying mechanism is still unclear. The mitokine growth differentiation factor 15 (GDF15) is a significant biomarker for mitochondrial disorder and is activated by the integrated stress response (ISR) pathway. The serum level of GDF15 was found to be correlated with the poor prognosis of gastric cancer patients. In this study, we found that high GDF15 protein expression might increase disease recurrence in adjuvant chemotherapy-treated gastric cancer patients. Moreover, treatment with mitochondrial inhibitors, especially oligomycin (a complex V inhibitor) and salubrinal (an ISR activator), respectively, was found to upregulate GDF15 and enhance cisplatin insensitivity of human gastric cancer cells. Mechanistically, it was found that the activating transcription factor 4-C/EBP homologous protein pathway has a crucial function in the heightened manifestation of GDF15. In addition, reactive oxygen species-activated general control nonderepressible 2 mediates the oligomycin-induced ISR, and upregulates GDF15. The GDF15-glial cell-derived neurotrophic factor family receptor a-like-ISR-cystine/glutamate transporter-enhanced glutathione production was found to be involved in cisplatin resistance. These results suggest that mitochondrial dysfunction might enhance cisplatin insensitivity through GDF15 upregulation, and targeting mitokine GDF15-ISR regulation might be a strategy against cisplatin resistance of gastric cancer.

Mitochondrial dysfunction promotes cell migration via reactive oxygen species-enhanced ß5-integrin expression in human gastric cancer SC-M1 cells.

BACKGROUND: Mitochondrial dysfunction has been shown to promote cancer cell migration. However, molecular mechanism by which mitochondrial dysfunction enhances gastric cancer (GC) cell migration remains unclear. METHODS: Mitochondria specific inhibitors, oligomycin and antimycin A, were used to induce mitochondrial dysfunction and to enhance cell migration of human gastric cancer SC-M1 cells. Antioxidant N-acetylcysteine (NAC) was used for evaluating the effect of reactive oxygen species (ROS). Protein expressions of epithelial-to-mesenchymal transition (EMT) markers and the cell-extracellular matrix (ECM) adhesion molecules, the integrin family, were analyzed. A migratory subpopulation of SC-M1 cells (SC-M1-3rd) was selected using a transwell assay for examining the association of mitochondrial bioenergetic function, intracellular ROS content and ß5-integrin expression. Clinicopathologic characteristics of ß5-integrin expression were analyzed in GC specimens by immunohistochemical staining. RESULTS: Treatments with mitochondrial inhibitors elevated mitochondria-generated ROS and cell migration of SC-M1 cells. The protein expression of ß5-integrin and cell surface expression of αvß5-integrin were upregulated, and which were suppressed by NAC. Pretreatments with NAC and anti-αvß5-integrin neutralizing antibody respectively prevented the mitochondrial dysfunction-induced cell migration. The selected migratory SC-M1-3rd cells showed impaired mitochondrial function, higher mitochondria-generated ROS, and increased ß5-integrin expression. The migration ability was also repressed by anti-αvß5-integrin neutralizing antibody. In clinical specimens, GCs with higher ß5-integrin protein expression had more aggressive behavior. In conclusion, mitochondrial dysfunction may lead to GC progression by enhancing migration through mitochondria-generated ROS mediated ß5-integrin expression. GENERAL SIGNIFICANCE: These results support the role of mitochondrial dysfunction in GC progression.

Effect of co-medications and potential risk factors of high-dose methotrexate-mediated acute hepatotoxicity in patients with osteosarcoma.

BACKGROUND: Taiwanese patients frequently experience severe hepatotoxicity associated with high-dose methotrexate (HD-MTX) treatment, which interferes with subsequent treatment. Drug-drug interactions occur when MTX is used in combination with proton pump inhibitors (PPIs), trimethoprim-sulfamethoxazole (TMP-SMX), or non-steroidal anti-inflammatory drugs (NSAIDs). In East Asia, real-world analyses on the effects of co-medication and other potential risk factors on the clinical course of HD-MTX-mediated acute hepatotoxicity in patients with osteogenic sarcoma (OGS) are limited. METHODS: This cohort study included patients with newly diagnosed OGS who were treated with HD-MTX between 2009 and 2017 at Taipei Veterans General Hospital. We collected data on the clinical course of HD-MTX-mediated acute hepatotoxicity, co-medications, and other potential risk factors, and analyzed the effects of these factors on the clinical course of HD-MTX-mediated acute hepatotoxicity. RESULTS: Almost all patients with OGS treated with HD-MTX developed acute hepatotoxicity with elevated alanine aminotransferase (ALT) levels. Most patients with Grade 3-4 ALT elevation failed to recover to Grade 2 within 7 days. Women and children are high-risk subgroups for HD-MTX-mediated elevation of ALT levels. Age is a factor that contributes to the pharmacokinetic differences of HD-MTX. However, the concurrent use of PPIs, TMP-SMX, or NSAIDs did not affect the elimination of MTX when administered with adequate supportive therapy. CONCLUSIONS: Co-administration of PPIs, TMP-SMX, or NSAIDs may have limited effects on acute hepatotoxicity in well-monitored and adequately pre-medicated patients with OGS undergoing chemotherapy with HD-MTX. Clinicians should pay particular attention to ALT levels when prescribing HD-MTX to children and women.

The Clinical Benefits of Antiresorptive Agents in Patients with Primary Breast Cancer Receiving Adjuvant Endocrine Therapy: A Systematic Review with Pairwise and Network Meta-analysis.

CONTEXT: Clinical trials have investigated the role of antiresorptive agents, including bisphosphonates and denosumab, in patients with primary breast cancer receiving adjuvant endocrine therapy, aiming for better bone protection and/or improving survival. OBJECTIVE: To summarize the clinical effects of antiresorptive agents in patients with early breast cancer receiving endocrine therapy. METHODS: We systematically reviewed and synthesized the clinical benefits and harms of antiresorptive agents in patients with early breast cancer receiving endocrine therapy by calculating the risk ratios (RRs). RESULTS: In the pooled meta-analysis, antiresorptive agents had significant clinical benefits on disease recurrence (RR 0.78, 95% CI 0.67-0.90) and locoregional recurrence (RR 0.69, 95% CI 0.49-0.95) in patients with breast cancer receiving endocrine therapy. Early use of antiresorptive agents has a beneficial effect on secondary endocrine therapy resistance instead of primary resistance. Safety analysis revealed that potential risk for osteonecrosis of the jaw (ONJ, RR 3.29, 95% CI 1.12-9.68) with antiresorptive agents; however, there is an insignificant difference in arthralgia. The subgroup analyses revealed that intervention with bisphosphonates might have profound clinical benefits, but also increased the occurrence of ONJ. A network meta-analysis further supported the clinical effects of early antiresorptive agent use compared with delayed use or placebo. CONCLUSION: Using antiresorptive agents early in patients with breast cancer receiving adjuvant endocrine therapy may provide additional benefits in risk reduction of recurrence, but there is a potential risk of ONJ.

Melatonin attenuates kainic acid-induced neurotoxicity in mouse hippocampus via inhibition of autophagy and α-synuclein aggregation.

In this study, the protective effect of melatonin on kainic acid (KA)-induced neurotoxicity involving autophagy and α-synuclein aggregation was investigated in the hippocampus of C57/BL6 mice. Our data showed that intraperitoneal injection of KA (20 mg/kg) increased LC3-II levels (a hallmark protein of autophagy) and reduced mitochondrial DNA content and cytochrome c oxidase levels (a protein marker of mitochondria). Atg7 siRNA transfection prevented KA-induced LC3-II elevations and mitochondria loss. Furthermore, Atg7 siRNA attenuated KA-induced activation of caspases 3/12 (biomarkers of apoptosis) and hippocampal neuronal loss, suggesting a pro-apoptotic role of autophagy in the KA-induced neurotoxicity. Nevertheless, KA-induced α-synuclein aggregation was not affected in the Atg7 siRNA-transfected hippocampus. The neuroprotective effect of melatonin (50 mg/kg) orally administered 1 hr prior to KA injection was studied. Melatonin was found to inhibit KA-induced autophagy-lysosomal activation by reducing KA-induced increases in LC3-II, lysosomal-associated membrane protein 2 (a biomarker of lysosomes) and cathepsin B (a lysosomal cysteine protease). Subsequently, KA-induced mitochondria loss was prevented in the melatonin-treated mice. At the same time, melatonin reduced KA-increased HO-1 levels and α-synuclein aggregation. Our immunoprecipitation study showed that melatonin enhanced ubiquitination of α-synuclein monomers and aggregates. The anti-apoptotic effect of melatonin was demonstrated by attenuating KA-induced DNA fragmentation, activation of caspases 3/12, and neuronal loss. Taken together, our study suggests that KA-induced neurotoxicity may be mediated by autophagy and α-synuclein aggregation. Moreover, melatonin may exert its neuroprotection via inhibiting KA-induced autophagy and a subsequent mitochondrial loss as well as reducing α-synuclein aggregation by enhancing α-synuclein ubiquitination in the CNS.

Mitochondria and aging.

Aging is a degenerative process that is associated with progressive accumulation of deleterious changes with time, reduction of physiological function and increase in the chance of disease and death. Studies in several species reveal a wide spectrum of alterations in mitochondria and mitochondrial DNA (mtDNA) with aging, including (1) increased disorganization of mitochondrial structure, (2) decline in mitochondrial oxidative phosphorylation (OXPHOS) function, (3) accumulation of mtDNA mutation, (4) increased mitochondrial production of reactive oxygen species (ROS) and (5) increased extent of oxidative damage to DNA, proteins, and lipids. In this chapter, we outline the common alterations in mitochondria of the aging tissues and recent advances in understanding the role of mitochondrial H(2)O(2) production and mtDNA mutation in the aging process and lifespan determination. In addition, we discuss the effect of caloric restriction on age-associated mitochondrial changes and its role in longevity. Taking these findings together, we suggest that decline in mitochondrial energy metabolism, enhanced mitochondrial oxidative stress, and accumulation of mtDNA mutations are important contributors to human aging.