Cell division cyclin 25C knockdown inhibits hepatocellular carcinoma development by inducing endoplasmic reticulum stress.

BACKGROUND: Cell division cyclin 25C (CDC25C) is a protein that plays a critical role in the cell cycle, specifically in the transition from the G2 phase to the M phase. Recent research has shown that CDC25C could be a potential therapeutic target for cancers, particularly for hepatocellular carcinoma (HCC). However, the specific regulatory mechanisms underlying the role of CDC25C in HCC tumorigenesis and development remain incompletely understood. AIM: To explore the impact of CDC25C on cell proliferation and apoptosis, as well as its regulatory mechanisms in HCC development. METHODS: Hepa1-6 and B16 cells were transduced with a lentiviral vector containing shRNA interference sequences (LV-CDC25C shRNA) to knock down CDC25C. Subsequently, a xenograft mouse model was established by subcutaneously injecting transduced Hepa1-6 cells into C57BL/6 mice to assess the effects of CDC25C knockdown on HCC development in vivo. Cell proliferation and migration were evaluated using a Cell Counting Kit-8 cell proliferation assays and wound healing assays, respectively. The expression of endoplasmic reticulum (ER) stress-related molecules (glucose-regulated protein 78, X-box binding protein-1, and C/EBP homologous protein) was measured in both cells and subcutaneous xenografts using quantitative real-time PCR (qRT-PCR) and western blotting. Additionally, apoptosis was investigated using flow cytometry, qRT-PCR, and western blotting. RESULTS: CDC25C was stably suppressed in Hepa1-6 and B16 cells through LV-CDC25C shRNA transduction. A xenograft model with CDC25C knockdown was successfully established and that downregulation of CDC25C expression significantly inhibited HCC growth in mice. CDC25C knockdown not only inhibited cell proliferation and migration but also significantly increased the ER stress response, ultimately promoting ER stress-induced apoptosis in HCC cells. CONCLUSION: The regulatory mechanism of CDC25C in HCC development may involve the activation of ER stress and the ER stress-induced apoptosis signaling pathway.

Parathyroid carcinoma: Report of 10 patients and literature review.

OBJECTIVE: Parathyroid carcinoma (PC) is a rare disease with high rates of misdiagnosis and recurrence. This report summarized the clinical and pathological characteristics of 10 patients with PC at our hospital, to improve the early recognition and prognosis of PC. METHODS: The clinical manifestations, imaging findings, pathological features, treatments, and prognostic data of 10 patients diagnosed with PC at the First Medical Center, Chinese PLA General Hospital from 2003 to 2021 were analyzed. RESULTS: There were 7 male and 3 female patients with PC whose average age was 41.4 ± 9.4 years. All patients had bone involvement (bone pain and/or osteoporosis), meanwhile 6 patients had kidney stones and 7 patients had palpable neck masses. Five patients presented with tumor metastasis, invading lymph nodes, lung, liver, or bone. Laboratory examinations revealed elevated serum total calcium (4.15 ± 0.81 mmol/L), parathyroid hormone (PTH, 1236.1 ± 519.9 pg/mL) and alkaline phosphatase (405.8 ± 219.0 IU/L) levels. Especially, hypercalcemic crisis occurred in 9 patients. The diagnosis of PC depended on histopathological features of the parathyroid tumor, including capsular and/or vascular invasion. All patients underwent at least en bloc resection. In the follow-up, six patients with relatively high preoperative PTH levels (1519.5 ± 436.8 pg/mL) relapsed postoperatively. Two patients with the Ki-67 index ≥ 10% in parathyroid tumor tissue and distant metastasis died within 2 years after the operation. CONCLUSION: Severe bone pain, kidney stones, hypercalcemic crisis, and markedly elevated PTH usually indicate PC. A markedly elevated PTH level, tumor metastasis, and the Ki-67 index ≥ 10% may be indicators of poor prognosis.

Paget's disease of bone: Report of 11 cases.

BACKGROUND: Paget's disease of bone (PDB) is a rare metabolic bone disease in China and is characterized by increased bone resorption and disorganized bone formation. The main clinical symptoms of PDB are focal or multiple bone pain and deformity with high disability. The disease has high missed diagnosis and misdiagnosis rates. This report summarizes the clinical manifestations, imaging and pathological features, and treatments of 11 patients with PDB at our hospital from 1993 to 2020 in order to improve the recognition and prognosis of PDB. CASE SUMMARY: There were eight male and three female patients whose average age was 48.7 ± 11.0 years with a PDB course of 1-16 years. Nine patients had bone pain and bone deformities in different parts of the body, the majority of which involved the long bones. Laboratory examinations revealed elevated serum alkaline phosphatase (ALP) in all patients with an average of 618 ± 460 IU/L (normal range 0-130 IU/L), and serum calcium and phosphorus levels were in the normal range. Imageology showed that osteolysis was usually combined with osteosclerosis and/or bone deformities in single or multiple bones. 99mTc-methylene diphosphonate bone scintigraphy revealed increased radionuclide uptake in the bone lesions. Six patients underwent bone tissue biopsy, and the typical pathological changes were a mosaic structure of the bone trabeculae with irregularly arranged cement lines and multinuclear osteoclasts. Ten of the 11 patients were effectively treated with bisphosphonates. CONCLUSION: Early diagnosis of the rare disease PDB can be made through elevated ALP levels and typical presentations on bone X-ray and from bone tissue biopsy.

Gas chromatography-mass spectrometry based metabolomics profile of hippocampus and cerebellum in mice after chronic arsenic exposure.

Intake of arsenic (As) via drinking water has been a serious threat to global public health. Though there are numerous reports of As neurotoxicity, its pathogenesis mechanisms remain vague especially its chronic effects on metabolic network. Hippocampus is a renowned area in relation to learning and memory, whilst recently, cerebellum is argued to be involved with process of cognition. Therefore, the study aimed to explore metabolomics alternations in these two areas after chronic As exposure, with the purpose of further illustrating details of As neurotoxicity. Twelve 3-week-old male C57BL/6J mice were divided into two groups, receiving deionized drinking water (control group) or 50 mg/L of sodium arsenite (via drinking water) for 24 weeks. Learning and memory abilities were tested by Morris water maze (MWM) test. Pathological and morphological changes of hippocampus and cerebellum were captured via transmission electron microscopy (TEM). Metabolic alterations were analyzed by gas chromatography-mass spectrometry (GC-MS). MWM test confirmed impairments of learning and memory abilities of mice after chronic As exposure. Metabolomics identifications indicated that tyrosine increased and aspartic acid (Asp) decreased simultaneously in both hippocampus and cerebellum. Intermediates (succinic acid) and indirect involved components of tricarboxylic acid cycle (proline, cysteine, and alanine) were found declined in cerebellum, indicating disordered energy metabolism. Our findings suggest that these metabolite alterations are related to As-induced disorders of amino acids and energy metabolism, which might therefore, play an important part in mechanisms of As neurotoxicity.

The mechanism of iron-compensation for manganese deficiency of Streptococcus pneumoniae.

Given their involvement in catalysis, infection, and biofilm formation, Fe and Mn are essential for bacterial survival and virulence. In this study, we found that Streptococcus pneumoniae (S. pneumoniae) could grow in the Mn-deficient medium (MDCM). Furthermore, findings showed that the Fe concentration in the bacterium increased when the Mn concentration decreased. In addition, it was noted that supplementing MDCM with Fe resulted in the recovery of bacterial growth. Quantitative proteomics using stable-isotope dimethyl labeling was performed to investigate the adaptive growth mechanism of S. pneumoniae under Mn-deficient conditions. It was found that the expression levels of 25 proteins were downregulated, whereas those of 54 proteins were upregulated in S. pneumoniae grown in MDCM. It was also noted that several of the downregulated proteins were involved in cell energy metabolism, amino acid synthesis, and reduction of oxidation products. More importantly, several ATP-binding cassette transporters related to Fe uptake, such as PiuA, PiaA, PitA, and SPD_1609, were overexpressed for increased Fe uptake from the MDCM. The results suggest that Mn deficiency disturbs multiple metabolic processes in S. pneumoniae. Furthermore, it causes a compensatory effect of Fe for Mn, which is beneficial for the survival of the bacterium in extreme environments. SIGNIFICANCE: The relationship between manganese and iron metabolism in S. pneumoniae has not been clearly revealed. In this paper, we suggest that Mn limitation disturbs multiple metabolic processes and evidently decreases the ATP level in the bacterium. In order to survive in this extreme environment, bacteria upregulated three type of Fe ion transporters PiuABC (heme), PiaABC (ferrichrome) and PitABC (Fe3+) to uptake enough Fe ions to response to Mn deficiency. Therefore, this study reveals a bacterial mechanism of Fe compensation for Mn, and provides new insight for investigating the relativeness of Fe and Mn metabolism of bacteria.

Evolution and molecular mechanism of PitAs in iron transport of Streptococcus species.

Iron is an essential element for almost all bacteria. The iron ATP-binding cassette (ABC) transporters located on the cell membrane affects bacterial virulence and infection. Although a variety of Fe3+-transporters have been found in bacteria, their evolutionary processes are rarely studied. Pneumococcal iron ABC transporter (PitA), a highly conserved Fe3+-transporter in most pathogenic bacteria, influences the capsule formation and virulence of bacteria. However, multiple sequence alignment revealed that PitA is expressed in four different variants in bacteria, and the structural complexity of these variants increases progressively. To more efficiently import Fe3+ ions into bacterial cells, bacteria have evolved a fused PitA from two separately expressed PitA-1 (SPD_0227) and PitA-2 (SPD_0226) proteins. Further biochemical characterization indicated that both PitA-1 and PitA-2 have weaker Fe3+-binding ability than their protein complex. More importantly, Glutathione S-Transferase (GST) pull-down and isothermal titration calorimetry (ITC) detection showed that PitA-1 and PitA-2 interact with each other via Tyr111-Leu37, Asn112-Gln38, Asn103-Leu33, and Asn103-Thr34. Further molecular dynamics (MD) simulations demonstrated that this interaction in full-length PitA is stronger than that in the two individual proteins. Deletion of PitA family genes could lead to decrease in the ability of iron acquisition and of adhesion and invasion of S. pneumoniae. Our study revealed the evolving state and molecular mechanism of Fe3+-transporter PitAs in bacteria and provided important information for understanding the iron transportation mechanism in bacteria and designing new antibacterial drugs.

Insulin resistance correlates with the arterial stiffness before glucose intolerance.

OBJECTIVE: The elevated plasma glucose level and/or insulin resistance in diabetes or impaired glucose tolerance play important roles in the pathogenesis of arterial stiffness. The present study investigated whether insulin resistance correlated with arterial stiffness before the development of glucose intolerance. METHODS: We conducted a cross-sectional analysis in 872 young to middle-age individuals with normal glucose tolerance (aged 36.2±8.5 years, BMI 24.6±3.1 kg/m2 [mean±SD]). The homeostasis model assessment (HOMA) index was used as a quantitative assessment of the fasting insulin resistance (FIR), and the plasma insulin level after glucose loading was adopted as an index of the post-challenge insulin resistance (PIR). The Matsuda index [ISI (composite)] was used as a measurement of the insulin sensitivity. The arterial stiffness assessed by the brachial-ankle pulse wave velocity (baPWV) was adopted to quantify its independent associations with insulin resistance. RESULTS: The univariate linear regression analysis indicated that the fasting plasma glucose level (FPG, ß = 68.2; 95% CI 40.9, 95.6; p<0.001), post-challenge plasma glucose level (PPG, ß = 25.3; 95% CI 15.6, 35.0; p<0.001), FIR (ß = 24.5; 95% CI 14.1, 35.0; p<0.001), PIR (ß=1.30; 95% CI 0.87, 1.73; p<0.001) and ISI (composite) (ß = -3.55; 95% CI -5.02, -2.07; p<0.001) were all significantly correlated with the baPWV. After adjustment for sex, age, BMI, heart rate, smoking, systolic blood pressure, total cholesterol, LDL-cholesterol and family history of diabetes, the multivariate linear regression analysis demonstrated that the PIR (model 1, ß = 0.39, p=0.038; model 2, ß = 0.39, p=0.035; model 3, ß = 0.39, p=0.035) was an independent contributor to the baPWV, while the FIR, FPG, PPG and ISI (composite) failed to show any significant contribution. CONCLUSION: The insulin resistance correlated with the arterial stiffness before glucose intolerance.

The human glucagon-like peptide-1 analogue liraglutide regulates pancreatic beta-cell proliferation and apoptosis via an AMPK/mTOR/P70S6K signaling pathway.

Glucagon-like peptide-1 (GLP-1), an effective therapeutic agent for the treatment of diabetes, has been proven to protect pancreatic beta cells through many pathways. Recent evidence demonstrates that AMP-activated protein kinase (AMPK), as a metabolic regulator, coordinates beta-cell protein synthesis through regulation of the mammalian target of rapamycin (mTOR) signaling pathway. The purpose of the present study was to explore whether liraglutide, a human GLP-1 analogue, protects beta cells via AMPK/mTOR signaling. We evaluated INS-1 beta-cell line proliferation using the Cell Counting Kit-8, and examined the effect of GLP-1 on cellular ATP levels using an ATP assay kit. mTOR pathway protein expression levels were tested by Western blotting and glucolipotoxicity-induced cell apoptosis was evaluated by flow cytometry. Liraglutide increased beta-cell viability at an optimum concentration of 100 nmol/L in the presence of 11.1 or 30 mmol/L glucose. Liraglutide (100 nmol/L) activated mTOR and its downstream effectors, 70-kDa ribosomal protein S6 kinase and eIF4E-binding protein-1, in INS-1 cells. This effect was abated by pathway blockers: the AMPK activator AICAR and the mTOR inhibitor rapamycin. Furthermore, the effect of liraglutide on beta-cell proliferation was inhibited by AICAR and rapamycin. Liraglutide increased cellular ATP levels. In addition, liraglutide protected beta cells from glucolipotoxicity-induced apoptosis. This response was also prevented by rapamycin treatment. These results suggest that the enhancement of beta-cell proliferation by that GLP-1 receptor agonist liraglutide is mediated, at least in part, by AMPK/mTOR signaling. Liraglutide also prevents beta-cell glucolipotoxicity by activating mTOR.

[Mechanism of apoptosis induced by trichostatin A in leukemia Molt-4 cells analyzed by microarray].

BACKGROUND & OBJECTIVE: Histone deacetylase is overexpressed in a variety of cancers and is closely correlated with oncogenic factors. A histone-deacetylase inhibitor, trichostatin A (TSA), has been shown to induce apoptosis in many cancer cells at submicromolar concentrations. However, the mechanism remains unknown. This study was to investigate the underlying mechanism of trichostatin A on apoptosis of Molt-4 cells by characterizing the global gene expression profiles before and after TSA treatment. METHODS: PI single-labeled flow cytometry, MTT and DNA ladder were used to observe the effect of TSA on apoptosis of MOLT-4 cells and normal human peripheral blood mononuclear cells (PBMC). Microarray and reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to detect the differentially expressed genes of Molt-4 cells after incubation with TSA. RESULTS: TSA could induce apoptosis in Molt-4 cells in a dose and time-dependent manner. Besides, the dose of TSA within the time duration which could induce significant apoptosis in Molt-4 cells did not demonstrate apparent cytotoxicity to PBMCs. After incubation with TSA for 9 hours, 313 genes were detected down-regulated by microarray. Proteins encoded by these genes included signal transduction molecules, transcription factors, enzymes etc., which were involved in the regulation of cell growth, differentiation and survival. STAT5A, MYC and ikaros were down-regulated by 80.4%, 77.3% and 83.1%, respectively. The changes of the three genes were confirmed by RT-PCR and the changes of STAT5A and MYC were further confirmed by Western blot. CONCLUSION: The inhibition of cell growth and induction of apoptosis by TSA in Molt-4 cells may be due to the changes of pro-proliferation genes and anti-apoptosis genes.