Objectives: Glutamic pyruvate transaminase (GPT2) catalyzes the reversible transamination between alanine and α-ketoglutarate (α-KG) to generate pyruvate and glutamate during cellular glutamine catabolism. The glutamate could be further converted to γ-aminobutyric acid (GABA). However, the role of GPT2 in tumor metastasis remains unclear. Methods: The wound healing and transwell assays were carried out to analyze breast cancer cell migration and invasion in vitro. Gene ontology analysis was utilized following RNA-sequencing to discover the associated molecule function. The mass spectrometry analysis following phosphoprotein enrichment was performed to discover the associated transcription factors. Most importantly, both the tail vein model and Mammary gland conditional Gpt2-/- spontaneous tumor mouse models were used to evaluate the effect of GPT2 on breast cancer metastasis in vivo. Results: GPT2 overexpression increases the content of GABA and promotes breast cancer metastasis by activating GABAA receptors. The delta subunit GABRD is necessary for the GPT2/GABA-induced breast cancer metastasis in xenograft and transgenic mouse models. Gpt2 knockout reduces the lung metastasis of the genetic Gpt2-/- breast cancer in mice and prolongs the overall survival of tumor burden mice. Mechanistically, GPT2-induced GABAA receptor activation increases Ca2+ influx by turning on its associated calcium channel, and the surged intracellular calcium triggers the PKC-CREB pathway activation. The activated transcription factor CREB accelerates breast cancer metastasis by upregulating metastasis-related gene expressions, such as PODXL, MMP3, and MMP9. Conclusion: In summary, this study demonstrates that GPT2 promotes breast cancer metastasis through up-regulated GABA activation of GABAAR-PKC-CREB signaling, suggesting it is a potential target for breast cancer therapy.
Background We studied the magnetic resonance spectroscopy (MRS) associations with clinicopathologic features of estrogen-dependent endometrial cancer (type I EC). Methods Totally 45 patients with type I EC who underwent preoperative multi-voxel MRS at 3.0 T were enrolled. The mean ratio of the Cho peak integral to the unsuppressed water peak integral (Cho/water) of the tumor was calculated. The Cho/water and apparent diffusion coefficient (ADC) of type I EC with and without local invasion, as well as with different levels of Ki-67 staining index (SI) (≤ 40% and > 40%), were compared. Correlation test was used to examine the relationship of Cho/water, as well as mean ADC, with Ki-67 SI, tumor stage, and tumor grade. Results The mean Cho/water of EC with Ki-67 SI ≤ 40% (2.28 ± 0.93) × 10 −3 was lower than that with Ki-67 SI > 40% (4.08 ± 1.00) × 10 −3 ( P < 0.001). The mean Cho/water of EC with deep and superficial myometrial invasion was (3.41 ± 1.26) × 10 −3 and (2.43 ± 1.11) × 10 −3 , respectively ( P = 0.011). There was no significant difference in Cho/water between type I EC with and without cervical invasioin ([2.68 ± 1.00] × 10 −3 and [2.77 ± 1.28] × 10 −3 , P = 0.866). The mean Cho/water of type I EC with and without lymph node metastasis was (4.02 ± 1.90) × 10 −3 and (2.60 ± 1.06) × 10 −3 , respectively ( P = 0.014). The Cho/water was positively correlated with the Ki-67 SI (r = 0.701, P < 0.001). There were no significant differences in ADC among groups (all P > 0.05). Conclusion MRS is helpful for preoperative assessment of clinicopathological features of type I EC.
Cholangiocarcinoma (CCA) is one of the most lethal types of solid tumors worldwide. Lymph node metastasis is common in the early stage, which is associated with recurrence and reduced survival time after CCA resection. The molecular pathogenesis of CCA is complex and requires extensive investigation. It involves multiple genomic alterations and the dysregulation of signaling pathways. Biliverdin reductase B (BLVRB) is a non-redundant NAD(P)H-dependent biliverdin reductase that regulates cellular redox status by reducing biliverdin to bilirubin. This study aimed at describing the biological functions and molecular mechanisms of BLVRB in human CCA. Prognostic clinical data showed that low expression BLVRB was associated with poor prognosis and lymph node metastasis. BLVRB depletion accelerated epithelial-mesenchymal transition (EMT), cell migration and invasion. In contrast, BLVRB overexpression was associated with reduced EMT and cell migration and invasion in CCA. BLVRB suppression activated Notch signaling, and activated c-Notch enhanced EMT by upregulating Snail expression levels, thereby increasing cell migration and invasion in CCA. Our results identified an unexpected function of BLVRB in CCA migration and invasion through the regulation of Notch/Snail signaling.
Calcium channel TRPV6 upregulation is associated with poor prognosis of breast cancer by promoting invasion and metastasis, and TRPV6 is a potential target for breast cancer therapy. However, the mechanism by which TRPV6 promotes breast metastasis remains unclear. Here, we report that TRPV6 expression is upregulated in metastatic breast cancers and that TRPV6 overexpression or upregulation accelerates primary breast cancer cell migration. In contrast, TRPV6 suppression decreases cell migration. Mechanistically, TRPV6 activates NFATC2 by increasing NFATC2IP phosphorylation at Ser204, and CDK5 is a candidate kinase that may perform this phosphorylation. Consequently, activated NFATC2 increases breast cancer metastasis by upregulating ADAMTS6 expression. These observations suggest that TRPV6 increases NFATC2 transcriptional activity by increasing NFATC2IP phosphorylation, which consequently upregulates ADAMTS6 expression to promote breast cancer metastasis.
Purpose Atypical adenomatous hyperplasia (AAH) and adenocarcinoma in situ (AIS) have been defined as preinvasive pulmonary adenocarcinoma lesions according to the 2015 World Health Organization lung adenocarcinoma classification. We aimed to search for the most common gene mutations in patients with AAH and AIS and investigate the distinctions between the two groups at the molecular level. Methods We performed targeted next-generation sequencing on 18 cases with AAH and 28 cases with AIS to screen for mutations with the Ion Torrent Oncomine Solid Tumor DNA panel. ALK and ROS1 fusions were detected by real-time PCR. Results Forty-six mutations were identified in 29 cases (76.1%), including 9 (50%) of 18 cases with AAH and 20 (71.4%) of 28 cases with AIS, in the following genes: EGFR , BRAF , KRAS , ERBB2 , TP53 , and FGFR3 . The mutations in EGFR , BRAF , KRAS , ERBB2, and TP53 genes were more common in AIS lesions than in AAH lesions, whereas the FGFR3 gene was more frequently mutated in AAH compared to AIS. ALK and ROS1 fusions were not detected in any of the lesions. Conclusions Based on the molecular evidence, the proposal that AAH and AIS are preinvasive lesions of pulmonary adenocarcinomas is of great significance, and it is necessary to distinguish AAH from AIS. Our study provided insights into the genetic alterations in the early stage of lung adenocarcinoma, which could be beneficial for the pathologic diagnosis and early detection of these lesions.
Although legumain has been found to be a prognostic factor in both breast cancer and colorectal cancer, its effects on gastric cancer are unknown. In this study, we investigated effects of legumain on gastric cancer and the correlation between legumain expression and prognosis of gastric cancer patients. SGC7901 cells were transduced with legumain cDNA (SGC7901-hLeg) for overexpression of legumain or with legumain shRNA to knock down legumain. In vitro tumor migration was examined by wound healing assay. Furthermore, a tumorigenicity and metastasis mouse model was used to examine legumain function in vivo; asparaginyl endopeptidase inhibitor (AEPI, an inhibitor of legumain) was injected to the mice (i.p.) to evaluate its therapeutic effect. Tissue microarray analysis from 112 gastric cancer patients was performed to evaluate the association between legumain expression and the cumulative survival time. Legumain was highly expressed in gastric cancer patients and some gastric cancer cell lines. Legumain promoted gastric cell migration in vitro and promoted gastric tumor growth and metastasis in vivo, and these effects were reversed by knockdown of legumain with shRNA or treated with AEPI. In gastric cancer clinical samples, legumain expression in tumor was significantly higher than in nontumor and was negatively associated with the cumulative survival rate. In conclusion, legumain was highly expressed in gastric adenocarcinoma; legumain promoted gastric cancer tumorigenesis and metastasis in vitro and in vivo. Legumain expression in tumor was a poor prognostic factor for gastric cancer patients, and legumain could be a potential target molecule for gastric cancer therapy in clinic.
OBJECTIVES:To analyze the clinical manifestations of primary adrenal insufficiency in Chinese boys, to investigate the prevalence of DAX1 and SF1 gene mutations, and to explore the association between gene mutations and clinical manifestations.SUBJECTS AND METHODS:A total of 25 boys with primary adrenal insufficiency were enrolled. Mutational analysis of the DAX1 and SF1 genes was done by direct sequencing.RESULTS:DAX1 gene mutations were found in 40% (10 of 25) of 46,XY phenotypic boys referred with adrenal insufficiency, and six of these were novel. One SF1 gene mutation was identified. These patients demonstrated diverse clinical presentations. There was no definite association between clinical manifestations and genetic mutations.CONCLUSIONS:DAX1 gene mutations are a relatively frequent cause of primary adrenal insufficiency. In contrast, mutation in the SF1 gene is seldom found. There is no definite relationship between gene mutations and clinical manifestations.
CONTEXT:DAX1 (for dosage-sensitive sex reversal, adrenal hypoplasia congenital critical region on the X chromosome, gene 1; also called NROB1) mutations are responsible for adrenal failure and hypogonadotropic hypogonadism in patients with adrenal hypoplasia congenita (AHC), through a loss of trans-repression of SF-1 (for steroidogenic factor-1)-mediated StAR (for steroidogenic acute regulatory protein) and LHbeta transcriptional activities and a reduction of GnRH expression. The correlation of clinical features with genetic and functional alterations of the gene was investigated in detail in AHC patients. OBJECTIVE:The present study aimed at identifying DAX1 mutations in Chinese AHC patients and investigating the functional defects of detected novel mutations. PATIENTS AND METHODS:Nine patients with AHC were recruited from eight families. DAX1 mutations were screened, and the transcriptional activities of the identified mutations were assessed in vitro. RESULTS:DAX1 mutations were detected in all nine patients enrolled in the study, with eight different mutations. Among the latter, seven are novel mutations, including two missense (L262P and C368F), one nonsense (Q222X), and four frame-shift (637delC, 652_653delAC, 973delC, and 774_775insCC) mutations. The functional studies showed that the mutant DAX1 was impaired by nuclear localization, loss of trans-repression of StAR and LHbeta transcriptional activities, and reduction of GnRH expression. CONCLUSION:These findings provide insight into the molecular events by which DAX1 mutations influence the hypothalamus-pituitary-gonadal and hypothalamus-pituitary-adrenal axis and lead to AHC and hypogonadotropic hypogonadism.