BCAR4 facilitates trastuzumab resistance and EMT in breast cancer via sponging miR-665 and interacting with YAP1

Breast cancer antiestrogen resistance 4 (BCAR4) has been suggested that can modulate cell behavior, resulting in tumorigenesis and chemoresistance. However, the underlying mechanisms of BCAR4 in trastuzumab resistance (TR) is still elusive. Here, we explored the function and the underlying mechanism of BCAR4 involving in TR. We found that BCAR4 is significantly upregulated in trastuzumab-resistant BC cells. Knockdown of BCAR4 could sensitize the BC cells to trastuzumab and suppress epithelial-mesenchymal transition (EMT). Mechanically, BCAR4 promotes yes-associated protein 1 (YAP1) expression by competitively sponging miR-665, to activated TGF-β signaling. Reciprocally, YAP1 could occupy the BCAR4 promoter to enhance its transcription, suggesting that there exists a positive feedback regulation between YAP1 and BCAR4. Targeting the BCAR4/miR-665/YAP1 axis may provide a novel insight of therapeutic approaches for TR in BC.

First demonstration of a fiber optic bolometer on a tokamak plasma (invited)

A fiber optic bolometer (FOB) was demonstrated observing a fusion plasma for the first time at the DIII-D tokamak. A FOB uses a fiber optics-based interferometric technique that is designed to have a high sensitivity to temperature changes [75 mK/(W/m²) responsivity in high vacuum with 0.38 mK noise level] with a negligible susceptibility to electromagnetic interference (EMI) that can be problematic for resistive bolometers in a tokamak environment. A single-channel test apparatus was installed on DIII-D consisting of a measurement FOB and shielded reference FOB. The single-channel FOB showed a negligible increase in the noise level during typical plasma operations (0.39 mK) compared to the benchtop results (0.38 mK), confirming an insignificant EMI impact to the FOB. Comparisons to DIII-D resistive bolometers showed good agreement with the single-channel FOB, indicating that the FOB is comparable to a resistive bolometer when the impulse calibration is applied. The noise-equivalent power density of the calibrated FOB during a plasma operation was 0.55 W/m² with an average sampling time of 20 ms. The major potential effect of ionizing radiation on the FOB would be the radiation-induced attenuation, which can be efficiently compensated for by adjusting the probing light power.

Genetic Analysis of a Family with Multiple Incidences of Prostate Cancer

A family with multiple members diagnosed with prostate cancer was identified, and genetic variants were analyzed. Three brothers were diagnosed with prostate cancer. Germline variants in BRCA1, BRCA2, TINF2, and CD19 were found through next-generation DNA sequencing using a hereditary cancer panel. The BRCA1 G275D variant was present in patients, but absent in the healthy member. An ELAC2 variant was found in 1 patient. Several mutations were predicted to be deleterious by a set of computation programs. Multiple gene mutations might contribute to the overall predisposition to prostate cancer in the family. Even in cases with potentially deleterious variants in BRCA1 or BRCA2, there could be diverse clinical manifestations.

Glomerular endothelial derived vesicles mediate podocyte dysfunction: A potential role for miRNA

MicroRNAs (miRNA) are shown to be involved in the progression of several types of kidney diseases. Podocytes maintain the integrity of the glomerular basement membrane. Extracellular vesicles (EV) are important in cell-to-cell communication as they can transfer cellular content between cells, including miRNA. However, little is known about how extracellular signals from the glomerular microenvironment regulate podocyte activity. Using a non-contact transwell system, communication between glomerular endothelial cells (GEnC) and podocytes was characterised in-vitro. Identification of transferred EV-miRNAs from GEnC to podocytes was performed using fluorescence cell tracking and miRNA mimetics. To represent kidney disease, podocyte molecular profiling and functions were analysed after EV treatments derived from steady state or activated GEnC. Our data shows activation of GEnC alters EV-miRNA loading, but activation was not found to alter EV secretion. EV delivery of miRNA to recipient podocytes altered cellular miRNA abundance and effector functions in podocytes, including decreased secretion of VEGF and increased mitochondrial stress which lead to altered cellular metabolism and cytoskeletal rearrangement. Finally, results support our hypothesis that miRNA-200c-3p is transfered by EVs from GEnC to podocytes in response to activation, ultimately leading to podocyte dysfunction.

The effect of acetylation on the protein stability of BmApoLp-III in the silkworm, Bombyx mori

Acetylation is an important, reversible posttranslational modification to a protein. In a previous study, we found that there were a large number of acetylated sites in various nutrient storage proteins of the silkworm haemolymph. In this study, we confirmed that acetylation can affect the stability of nutrient storage protein Bombyx mori apolipophorin-III (BmApoLp-III). First, the expression of BmApoLp-III could be upregulated when BmN cells were treated with the deacetylase inhibitor panobinostat (LBH589); similarly, the expression was downregulated when the cells were treated with the acetylase inhibitor C646. Furthermore, the increase in acetylation by LBH589 could inhibit the degradation and improve the accumulation of BmApoLp-III in BmN cells treated with cycloheximide and MG132 respectively. Moreover, we found that an increase in acetylation could decrease the ubiquitination of BmApoLp-III and vice versa; therefore, we predicted that acetylation could improve the stability of BmApoLp-III by competing for ubiquitination and inhibiting the protein degradation pathway mediated by ubiquitin. Additionally, BmApoLp-III had an antiapoptosis function that increased after LBH589 treatment, which might have been due to the improved protein stability after acetylation. These results have laid the foundation for further study on the mechanism of acetylation in regulating the storage and utilization of silkworm nutrition.

Cisplatin-mediated down-regulation of miR-145 contributes to up-regulation of PD-L1 via the c-Myc transcription factor in cisplatin-resistant ovarian carcinoma cells

Immune tolerance is one of the leading causes of chemotherapy resistance in carcinoma cases. Studies have shown that programmed cell death ligand-1 (PD-L1), an inhibitory molecule expressed by cancer cells, plays a significant role in immune tolerance through the induction of T cell dysfunction. The results of our RNA sequencing in previous studies revealed that microRNA-145 (miR-145), which is known to be down-regulated by cisplatin in cisplatin-resistant ovarian cancer cells, also represses gene PD-L1 expression. However, the mechanism by which miR-145 contributes to regulate PD-L1 expression in cisplatin resistance of ovarian cancer is yet to be fully understood. Here, we show that cisplatin-mediated miR-145 down-regulation increased PD-L1 expression via targeting the c-Myc transcription factor, thereby inducing T cell apoptosis in vitro. We also report that expression of miR-145 is negatively correlated with PD-L1 expression in human ovarian cancer tissues, malignant grades and the recurrent risks of ovarian cancer after chemotherapy. In summary, our findings suggest that the miR-145/c-Myc/PD-L1 axis contributes to cisplatin resistance in ovarian cancer and support that miR-145 might act as an adjuvant therapeutic target in chemotherapy of ovarian cancer.

Significance of preoperative calculation of uterine weight as an indicator for preserving the uterus in pelvic reconstructive surgery

Recently, increasing evidence has shown that uterus preservation is beneficial for pelvic organ prolapse (POP) patients, both physiologically and psychologically. However, the preoperative indicators for uterus preservation have rarely been examined. The current study was designed to determine the relationship between the preoperative evaluated uterus weight and the operation selection (preserving the uterus or not) in pelvic reconstructive surgery (PRS) using vaginal meshes. First, in a series of 96 patients undergoing hysterectomy, the uterine weight was calculated by preoperative ultrasound measurements, and was then compared with the postoperative actual weight of the uterus. Subsequently, in a series of 65 patients undergone PRS using vaginal meshes and preserving the uterus, the uterine weight was calculated by preoperative ultrasound measurements. Lastly, in a series of 43 patients with a uterine weight > 56.12 g who had undergone PRS using vaginal meshes, the operation success rate in patients with a preserved uterus was compared to patients for whom the uterus was not preserved. The results showed that uterus weight can be evaluated by ultrasound and used as a preoperative indicator for whether the uterus should be preserved or not in PRS when using vaginal meshes. It was indicated that preoperative evaluation of uterine weight is beneficial for surgical planning and guidance.

Characterization of a new HLA-B allele, B*15:179:02

A novel HLA-B allele, B*15:179:02, has been identified during typing of donors in Anhui province, China.

Multipoint targeting of the PI3K/mTOR pathway in mesothelioma

BACKGROUND

Mesothelioma is a notoriously chemotherapy-resistant neoplasm, as is evident in the dismal overall survival for patients with those of asbestos-associated disease. We previously demonstrated co-activation of multiple receptor tyrosine kinases (RTKs), including epidermal growth factor receptor (EGFR), MET, and AXL in mesothelioma cell lines, suggesting that these kinases could serve as novel therapeutic targets. Although clinical trials have not shown activity for EGFR inhibitors in mesothelioma, concurrent inhibition of various activated RTKs has pro-apoptotic and anti-proliferative effects in mesothelioma cell lines. Thus, we hypothesised that a coordinated network of multi-RTK activation contributes to mesothelioma tumorigenesis.

METHODS

Activation of PI3K/AKT/mTOR, Raf/MAPK, and co-activation of RTKs were evaluated in mesotheliomas. Effects of RTK and downstream inhibitors/shRNAs were assessed by measuring mesothelioma cell viability/growth, apoptosis, activation of signalling intermediates, expression of cell-cycle checkpoints, and cell-cycle alterations.

RESULTS

We demonstrate activation of the PI3K/AKT/p70S6K and RAF/MEK/MAPK pathways in mesothelioma, but not in non-neoplastic mesothelial cells. The AKT activation, but not MAPK activation, was dependent on coordinated activation of RTKs EGFR, MET, and AXL. In addition, PI3K/AKT/mTOR pathway inhibition recapitulated the anti-proliferative effects of concurrent inhibition of EGFR, MET, and AXL. Dual targeting of PI3K/mTOR by BEZ235 or a combination of RAD001 and AKT knockdown had a greater effect on mesothelioma proliferation and viability than inhibition of individual activated RTKs or downstream signalling intermediates. Inhibition of PI3K/AKT was also associated with MDM2-p53 cell-cycle regulation.

CONCLUSIONS

These findings show that PI3K/AKT/mTOR is a crucial survival pathway downstream of multiple activated RTKs in mesothelioma, underscoring that PI3K/mTOR is a compelling target for therapeutic intervention.

Gab2 regulates the migratory behaviors and E-cadherin expression via activation of the PI3K pathway in ovarian cancer cells

Ovarian cancer, the most deadly gynecologic malignancy, is often diagnosed late and at the advanced stage when the cancer cells have already migrated and invaded into other tissues and organs. Better understanding of the mechanism of metastasis in ovarian cancer cells is essential to the design of effective therapy. In this study, we investigated the function of scaffolding adaptor protein Gab2 in ovarian cancer cells. Gab2 is found to be overexpressed in a subset of ovarian tumors and cancer cell lines. Gab2 expression mainly regulates the migratory behaviors of ovarian cancer cells. Overexpression of Gab2 promotes the migration and invasion, and down-regulates E-cadherin expression in ovarian cancer cells with low-Gab2 expression. Conversely, knockdown of Gab2 expression inhibits the migration and invasion, and promotes E-cadherin expression in ovarian cancer cells with high-Gab2 expression. By expressing Gab2 wild type and Gab2 mutants that are defective in activation the PI3K and Shp2-Erk pathways, we find that Gab2 inhibits E-cadherin expression and enhances the expression of Zeb1, a transcription factor involved in epithelial-to-mesenchymal transition (EMT), and cell migration and invasion through the activation of the PI3K pathway. Knockdown of Zeb1 expression blocks Gab2-induced suppression of E-cadherin expression and increase in cell invasion. LY294002 and GDC-0941, inhibitors of PI3K, or Rapamycin, an inhibitor of PI3K downstream target mTOR, can reverse the effects of Gab2 on migration and invasion. Overall, our studies reveal that Gab2 overexpression, via activation of the PI3K-Zeb1 pathway, promotes characteristics of EMT in ovarian cancer cells.

Prognostic significance of APE1 cytoplasmic localization in human epithelial ovarian cancer

Cytoplasmic localization of apurinic/apyrimidinic endonuclease 1 (APE1) correlates with different tumorigenic processes and poor prognosis in several cancer types. However, rare investigation into the prognosis value of cytoplasmic localization of APE1 was provided in ovarian cancer. The present study examined for the first time the cytoplasmic localization of APE1 in epithelial ovarian cancer (EOC) by immunohistochemistry. The relationship between cytoplasmic localization of APE1 and clinicopathological parameters, as well as the correlation between cytoplasmic localization of APE1 and prognosis, was investigated. We found that cytoplasmic positivity was significantly higher in EOCs with low tumor differentiation (P = 0.002) and was significantly higher in advanced Federation International of Gynecology and Obstetrics (FIGO) stage (III + IV) patients compared to that in early FIGO stage (I + II) patients (40.7% vs. 11.8%; P = 0.002). No significant difference was observed in APE1 pattern referring to age, tumor size, family history, histological type, ascites, and lymphatic metastasis (P > 0.05). In addition, a lower survival rate was found in patients with cytoplasmic positive localization of APE1 compared to that in patients with cytoplasmic negative localization (P < 0.05). All these findings suggest that cytoplasmic localization of APE1 is associated with tumor progression and might be a valuable prognostic marker for EOC.

Expression and characterization of the human YWK-II gene, encoding a sperm membrane protein related to the alzheimer betaA4-amyloid precursorprotein

The YWK-II cDNA, RSD-2, encoding a sperm membrane protein was isolated from a rat testis cDNA expression library. Using the RSD-2 insert in combination with rapid amplification of cDNA ends (RACE), the corresponding human gene was isolated from a human testis cDNA expression library. The human testis cDNA, HSD-2, is 3654 bp in length and contains an open reading frame of 763 codons. Hydropathicity analysis showed that the deduced polypeptide is a single strand transmembrane protein. The deduced polypeptide has partial homology with the amyloid precursor protein (APP) and high homology with the amyloid precursor homologue, APLP2/APPH. The YWK-II gene was mapped and assigned to human chromosome locus: 11q24-25. Northern blotting of various human tissue RNAs using the HSD-2 cDNA as a probe showed that the gene is transcribed ubiquitously. The cytoplasmic domain of HSD-2 was expressed in Escherichia coli. In-vitro studies showed that the recombinant polypeptide bound to a GTP-binding protein (G(o)) and was phosphorylated by protein kinase C and cdc2 kinase. In mammalian F11 cells, the recombinant polypeptide was found to be coupled to G(o). Thus, the YWK-II component has the characteristics of a G(o)-coupled receptor and may be involved in G(o)-mediated signal transduction pathway. Protein kinase C and cdc2 kinase may regulate this pathway in spermatozoa by phosphorylating the cytoplasmic domain of the YWK-II component.

J domain-independent regulation of the Rb family by polyomavirus large T antigen

The ability of polyomavirus large T antigen (LT) to promote cell cycling, to immortalize primary cells, and to block differentiation has been linked to its effects on tumor suppressors of the retinoblastoma susceptibility (Rb) gene family. Our previous studies have shown that LT requires an intact N-terminal DnaJ domain, in addition to an Rb binding site, for activation of simple E2F-containing promoters and stimulation of cell cycle progression. Here we show that some LT effects dependent on interaction with the Rb family are largely DnaJ independent. In differentiating C2C12 myoblasts, overexpression of LT caused apoptosis. Although this activity of LT completely depended on Rb binding, LTs with mutations in the J domain remained able to kill. Comparisons of Rb(-) and J(-) LTs revealed additional differences. Wild-type but not Rb(-) LT activated the cyclin A promoter under serum starvation conditions. Genetic analysis of the promoter linked the Rb requirement to an E2F site in the promoter. LTs with mutations in the J domain were still able to activate the promoter. Finally, J mutant LTs caused changes in phosphorylation of both pRb and p130. In the case of p130, Thr-986 was shown to be a site that is regulated by J mutant LT. Taken together, these observations reveal that LT regulation of Rb function can be separated into both DnaJ-dependent and DnaJ-independent pathways.

[DNA damage and c-myc gene expression of NIH3T3 cell induced by superoxide anion]

OBJECTIVE

To study the DNA damage, membrane lipid peroxidation, and c-myc gene expression of NIH3T3 cell induced by superoxide anion(O2.-).

METHODS

The superoxide anion(O2.-) was produced by reactive system of xanthine-xanthine oxidase (X-XO) and the DNA-EB complex, malondialdehyde (MDA) content and expression of c-myc gene were measured by means of fluorescence, thiobarbituric acid (TBA) assay and DNA-RNA situ hybridization with digoxigenin labeled probes respectively.

RESULTS

The O2.- of high concentration(X: 20 micrograms, XO: 2 x 10(-3) U) reacted with isolated DNA from NIH3T3 cell directly which caused DNA damage obviously. When the O2.- of high concentration reacted with whole NIH3T3 cell, the amount of MDA increased and fluorescence intensity of DNA-EB complex decreased which mean lipid peroxidation of membrane and gene damage of the cell respectively. When the producing O2.- of high concentration reactive system existing FeSO4, the phenomena mentioned above showed obviously. Enough amount of catalase showed the inhibit effects, but it could not completely inhibit the DNA damage of whole cell. The c-myc gene expression was observed in the cell treated with O2.- of middle (X: 4 micrograms, XO: 4 x 10(-4) U) and high concentration, but it was not observed in the cell treated with O2.- of low concentration(X: 0.4 micrograms, XO: 4 x 10(-5) U).

CONCLUSIONS

DNA damage of the whole cell induced by extracellular O2.- was able to act through the pathway of membrane lipid peroxidation in which hydrogen peroxide is important and the other pathways such as signal transduction of the cell might also be existed. The expression of c-myc gene of NIH3T3 cell induced by O2.- was related closely to the concentration of O2.-.

[Vascular endothelial growth factor gene therapy for peripheral artery disease: experimental study]

OBJECTIVE

To Study experimentally VEGF gene for treatment of peripheral artery disease.

METHODS

The human VEGF cDNA was cloned into the eukaryotic expression vector pcD2. Using gene suture, the recombinant plasmid was transferred into the hindlimbs' adductor of Rhesus monkey, of which the distal end of the external iliac arteries were ligated and the femoral arteries were completely excised. With angiography, the biological effect of VEGF gene in experimental animals was investigated. Safety tests were analyzed by transferring of VEGF into mouse, rat, and Rhesus monkey, evaluated by biochemistry analysis, histopathological examination, PCR, and indirect ELISA.

RESULTS

The transfer of VEGF gene stimulated the formation of focal microvessels, established collateral circulation, and augmented blood perfusion. The system had no adverse effect and remarkable pathological change in mouse, rat, and Rhesus monkey.

CONCLUSION

The experimental studies indicated that VEGF would be effective and safe for clinical trial after approval.

The DnaJ domain of polyomavirus large T antigen is required to regulate Rb family tumor suppressor function

Tumor suppressors of the retinoblastoma susceptibility gene family regulate cell growth and differentiation. Polyomavirus large T antigens (large T) bind Rb family members and block their function. Mutations of large T sequences conserved with the DnaJ family affect large T binding to a cellular DnaK, heat shock protein 70. The same mutations abolish large T activation of E2F-containing promoters and Rb binding-dependent large T activation of cell cycle progression. Cotransfection of a cellular DnaJ domain blocks wild-type large T action, showing that the connection between the chaperone system and tumor suppressors is direct. Although they are inactive in assays dependent on Rb family binding, mutants in the J region retain the ability to associate with pRb, p107, and p130. This suggests that binding of Rb family members by large T is not sufficient for their inactivation and that a functional J domain is required as well. This work connects the DnaJ and DnaK molecular chaperones to regulation of tumor suppressors by polyomavirus large T.

[A primary observation on the effect of cell fusion on metastatic potential of tumor cells]

Mouse spleen cells transfected with pSV2 neo by CaPO4 precipitation were fused with highly metastatic cell clone (PLA801-D95) from human large cell lung cancer cell line. Hybrid cell clone PMS-2 was obtained after G418(400/ml)selection. After injection of 7 x 10(6) PMS-2 cells into nude mice, there was a tumor nodule developed, but the metastatic foci could not be found while 3 x 10(6) PLA801-D95 cells would metastasize to lung and lymph nodes after they were injected into nude mice. It might indicate that sometime mouse spleen cells could not suppress tumor formation but the metastatic potential could be suppressed by the fusion of mouse spleen cells with the lung cancer cells. The results of growth curve, serum independence and incorporation rates of H-thymidine all showed that the growth rates of parental cells were higher than those of PMS-2. Our data suggest that suppression of tumorigenicity and metastatic potential could be controlled by different kinds of genes, and the cloning of metastasis suppressor gene by subtractive hybridization is ongoing in our laboratory.

Analysis of human growth hormone gene 5' sequences in isolated growth hormone deficiency patients

Human growth hormone (hGH) gene deletion (6.7 to 7.6 kb) is one of the causes of isolated growth hormone deficiency (IGHD), named IGHD IA. IGHD IA, however, only accounts for about 10% of the total IGHD patients. Most IGHD is caused by unknown mechanisms. Here, hGH gene 5' sequences in three IGHD patients without hGH gene deletion were analysed to see if there was any mutation hindering the expression of the hGH gene.