Regulation of PKD2 channel function by TACAN.

Autosomal dominant polycystic kidney disease is caused by mutations in the membrane receptor PKD1 or the cation channel PKD2. TACAN (also termed TMEM120A), recently reported as an ion channel in neurons for mechanosensing and pain sensing, is also distributed in diverse non-neuronal tissues, such as kidney, heart and intestine, suggesting its involvement in other functions. In this study, we found that TACAN is in a complex with PKD2 in native renal cell lines. Using the two-electrode voltage clamp in Xenopus oocytes, we found that TACAN inhibits the channel activity of PKD2 gain-of-function mutant F604P. TACAN fragments containing the first and last transmembrane domains interacted with the PKD2 C- and N-terminal fragments, respectively. The TACAN N-terminus acted as a blocking peptide, and TACAN inhibited the function of PKD2 by the binding of PKD2 with TACAN. By patch clamping in mammalian cells, we found that TACAN inhibits both the single-channel conductance and the open probability of PKD2 and mutant F604P. PKD2 co-expressed with TACAN, but not PKD2 alone, exhibited pressure sensitivity. Furthermore, we found that TACAN aggravates PKD2-dependent tail curvature and pronephric cysts in larval zebrafish. In summary, this study revealed that TACAN acts as a PKD2 inhibitor and mediates mechanosensitivity of the PKD2-TACAN channel complex. KEY POINTS: TACAN inhibits the function of PKD2 in vitro and in vivo. TACAN N-terminal S1-containing fragment T160X interacts with the PKD2 C-terminal fragment N580-L700, and its C-terminal S6-containing fragment L296-D343 interacts with the PKD2 N-terminal A594X. TACAN inhibits the function of the PKD2 channel by physical interaction. The complex of PKD2 with TACAN, but not PKD2 alone, confers mechanosensitivity.

MCU inhibition protects against intestinal ischemia‒reperfusion by inhibiting Drp1-dependent mitochondrial fission.

Intestinal ischemia‒reperfusion (IIR) injury is a common complication of surgery, but clear molecular insights and valuable therapeutic targets are lacking. Mitochondrial calcium overload is an early sign of various diseases and is considered a vital factor in ischemia‒reperfusion injury. The mitochondrial calcium uniporter (MCU), which is located on the inner mitochondrial membrane, is the primary mediator of calcium ion entry into the mitochondria. However, the specific mechanism of MCU in IIR injury remains to be clarified. In this study, we generated an IIR model using C57BL/6 mice and Caco-2 cells and found increases in the calcium levels and MCU expression following IIR injury. The specific inhibition of MCU markedly attenuated IIR injury. Moreover, MCU knockdown alleviates mitochondrial dysfunction by reducing oxidative stress and apoptosis. Mechanistically, MCU knockdown substantially reduced the translocation of Drp1 and thus its binding to Fis1 receptors, resulting in decreased mitochondrial fission. Taken together, our findings demonstrated that MCU is a novel upstream regulator of Drp1 in ischemia‒reperfusion and represents a predictive and therapeutic target for IIR.

[The correlation of synuclein-γ and matrix metalloproteinase 9 in breast cancer].

OBJECTIVES: To evaluate the expression of synuclein-γ (SNCG) and metalloproteinase 9 (MMP-9) both in the invasive ductal breast cancer samples and T47D and T47D(SNCG)- cell lines, to investigate the correlation between SNCG and MMP-9. METHODS: Totally 96 invasive ductal breast cancer samples (female, mean age of (56 ± 8) years) were collected between June 2009 and June 2012. The expressions of SNCG and MMP-9 were investigated by immunohistochemistry. T47D and SNCG knock down T47D(SNCG)- cell lines were established and SNCG and MMP-9 protein expression were investigated by Western blot and gene expression by real-time PCR. RESULTS: Among 96 samples, 26 (27.1%) of them co-expressed SNCG and MMP-9, 30(31.2%) of them expressed neither SNCG nor MMP-9. The expression of SNCG was correlated with the expression of MMP-9 (r = 0.655, P = 0.000).SNCG mRNA level of T47D cell line was 13.5 fold of T47D(SNCG)- cell line and SNCG protein expression was 2.1 fold. While MMP-9 mRNA level of T47D cell line was 7.3 fold of T47D(SNCG)- cell line and MMP-9 protien expression was 1.6 fold.When SNCG was knocked down, the expression of MMP-9 decreased. CONCLUSIONS: SNCG and MMP-9 are significantly correlated with each other in breast cancer. SNCG may promote the invasion and metastasis of breast cancer mediated by up-regulating the expression of MMP-9.

Inhibition of TRPP3 by calmodulin through Ca2+/calmodulin-dependent protein kinase II.

Transient receptor potential (TRP) polycystin-3 (TRPP3) is a non-selective cation channel activated by Ca2+ and protons and is involved in regulating ciliary Ca2+ concentration, hedgehog signaling and sour tasting. The TRPP3 channel function and regulation are still not well understood. Here we investigated regulation of TRPP3 by calmodulin (CaM) by means of electrophysiology and Xenopus oocytes as an expression model. We found that TRPP3 channel function is enhanced by calmidazolium, a CaM antagonist, and inhibited by CaM through binding of the CaM N-lobe to a TRPP3 C-terminal domain not overlapped with the EF-hand. We further revealed that the TRPP3/CaM interaction promotes phosphorylation of TRPP3 at threonine 591 by Ca2+/CaM-dependent protein kinase II, which mediates the inhibition of TRPP3 by CaM.

Bioinformatic profiling of prognosis-related genes in the breast cancer immune microenvironment.

In the microenvironment of breast cancer, immune cell infiltration is associated with an improved prognosis. To identify immune-related prognostic markers and therapeutic targets, we determined the lymphocyte-specific kinase (LCK) metagene scores of samples from breast cancer patients in The Cancer Genome Atlas. The LCK metagene score correlated highly with other immune-related scores, as well as with the clinical stage, prognosis and tumor suppressor gene mutation status (BRCA2, TP53, PTEN) of patients in the four breast cancer subtypes. A weighted gene co-expression network analysis was performed to detect representative genes from LCK metagene-related gene modules. In two of these modules, the levels of the co-expressed genes correlated highly with LCK metagene levels, so we conducted an enrichment analysis to discover their functions. We also identified differentially expressed genes in samples with high and low LCK metagene scores. By examining the overlapping results from these analyses, we obtained 115 genes, and found that 22 of them were independent predictors of overall survival in breast cancer patients. These genes were validated for their prognostic and diagnostic value with external data sets and paired tumor and non-tumor tissues. The genes identified herein could serve as diagnostic/prognostic markers and immune-related therapeutic targets in breast cancer.

Protecting Effects of Gonadotropin-Releasing Hormone Agonist on Chemotherapy-Induced Ovarian Damage in Premenopausal Breast Cancer Patients: A Systematic Review and Meta-Analysis.

OBJECTIVE: There is no universal consensus on whether gonadotropin-releasing hormone (GnRH) agonist could protect chemotherapy-induced ovarian damage in premenopausal breast cancer patients. This meta-analysis was conducted to estimate the protective effects of GnRH agonist on premenopausal breast cancer patients in details. METHODS: PubMed, Cochrane Library, Embase, CNKI and the Chinese Wangfang Database, conference proceedings and clinical trials were searched to find studies reported since 2000. Heterogeneity for the eligible data was assessed and a pooled odds ratio (OR) with 95% confidence interval (CI) was calculated. RESULTS: Resumption of menses rate was improved in the GnRH agonist and chemotherapy-combination groups versus chemotherapy-alone groups (OR = 1.36, 95% CI: 1.19-1.56). Furthermore, the results indicated that spontaneous pregnancy rate was improved in the experimental groups versus the controls (OR = 1.90, 95% CI: 1.06-3.41). In addition, no publication bias was found using a Begg's funnel plot. CONCLUSION: The results of the current meta-analysis indicate that a GnRH agonist could improve resumption of menses rate and pregnancy rate for premenopausal breast cancer patients. However, more evaluation may be considered to prove this theory.

An Experimental Analysis of the Molecular Effects of Trastuzumab (Herceptin) and Fulvestrant (Falsodex), as Single Agents or in Combination, on Human HR+/HER2+ Breast Cancer Cell Lines and Mouse Tumor Xenografts.

PURPOSE: To investigate the effects of trastuzumab (herceptin) and fulvestrant (falsodex) either in combination or alone, on downstream cell signaling pathways in lab-cultured human HR+/HER2+ breast cancer cell lines ZR-75-1 and BT-474, as well as on protein expression levels in mouse xenograft tissue. METHODS: Cells were cultivated in the presence of trastuzumab or fulvestrant or both. Molecular events that resulted in an inhibition of cell proliferation and cell cycle progression or in an increased rate of apoptosis were studied. The distribution and abundance of the proteins p-Akt and p-Erk expressed in these cells in response to single agents or combinatorial treatment were also investigated. In addition, the effects of trastuzumab and fulvestrant, either as single agents or in combination on tumor growth as well as on expression of the protein p-MED1 expressed in in vivo mouse xenograft models was also examined. RESULTS: Cell proliferation was increasingly inhibited by trastuzumab or fulvestrant or both, with a CI<1 and DRI>1 in both human cell lines. The rate of apoptosis increased only in the BT-474 cell line and not in the ZR-75-1 cell line upon treatment with fulvestrant and not trastuzumab as a single agent (P<0.05). Interestingly, fulvestrant, in combination with trastuzumab, did not significantly alter the rate of apoptosis (in comparison with fulvestrant alone), in the BT-474 cell line (P>0.05). Cell accumulation in the G1 phase of cell cycle was investigated in all treatment groups (P<0.05), and the combination of trastuzumab and fulvestrant reversed the effects of fulvestrant alone on p-Akt and p-Erk protein expression levels. Using ZR-75-1 or BT-474 to generate in vivo tumor xenografts in BALB/c athymic mouse models, we showed that a combination of both drugs resulted in a stronger inhibition of tumor growth (P<0.05) and a greater decrease in the levels of activated MED1 (p-MED1) expressed in tumor issues compared with the use of either drug as a single agent. CONCLUSIONS: We demonstrate that the administration of trastuzumab and fulvestrant in combination results in positive synergistic effects on both, ZR-75-1 and BT-474 cell lines. This combinatorial approach is likely to reduce physiological side effects of both drugs, thus providing a theoretical basis for the use of such combination treatment in order to resolve HR+/HER2+ triple positive breast cancer that has previously been shown to be resistant to endocrine treatment alone.

Increased chemosensitivity and radiosensitivity of human breast cancer cell lines treated with novel functionalized single-walled carbon nanotubes.

Hypoxia is a major cause of treatment resistance in breast cancer. Single-walled carbon nanotubes (SWCNTs) exhibit unique properties that make them promising candidates for breast cancer treatment. In the present study, a new functionalized single-walled carbon nanotube carrying oxygen was synthesized; it was determined whether this material could increase chemosensitivity and radiosensitivity of human breast cancer cell lines, and the underlying mechanisms were investigated. MDA-MB-231 cells growing in folic acid (FA) free medium, MDA-MB-231 cells growing in medium containing FA and ZR-75-1 cells were treated with chemotherapy drugs or radiotherapy with or without tombarthite-modified-FA-chitosan (R-O2-FA-CHI)-SWCNTs under hypoxic conditions, and the cell viability was determined by water-soluble tetrazolium salts-1 assay. The cell surviving fractions were determined by colony forming assay. Cell apoptosis induction was monitored by flow cytometry. Expression of B-cell lymphoma 2 (Bcl-2), survivin, hypoxia-inducible factor 1-α (HIF-1α), multidrug resistance-associated protein 1 (MRP-1), P-glycoprotein (P-gp), RAD51 and Ku80 was monitored by western blotting. The novel synthesized R-O2-FA-CHI-SWCNTs were able to significantly enhance the chemosensitivity and radiosensitivity of human breast cancer cell lines and the material exhibited its expected function by downregulating the expression of Bcl-2, survivin, HIF-1α, P-gp, MRP-1, RAD51 and Ku80.

[The effect of breast cancer specific gene 1 in the prognosis of breast cancer].

OBJECTIVE: To detect breast cancer specific gene 1 (BCSG1) expression in different breast tissue, analysis its correlation with clinical parameters and evaluate the prognosis of breast cancer. METHODS: The expression of BCSG1 was detected by reverse transcription-polymerase chain reaction (RT-PCR) in surgical specimens from 84 cases of breast disease patients selected randomly at XinHua Hospital affiliated with Shanghai Second Medical University from September 1999 to December 2002. Of 84 cases, 72 case were breast cancer. Statistic analysis BCSG1 gene expression correlation with clinical parameters of breast cancer. 72 breast cancers were followed up (4 - 43 months) to set up independent prognosis factor by survival analysis. RESULTS: BCSG1 was undetectable in all benign breast lesions, while was detectable in 36.1% of all breast cancer samples (26/72), in which 79.2% of stage III/IV cases were positive (19/24). The expression of BCSG1 was tightly correlated with the stage (P = 0.000) and the size of tumor (P = 0.007). Both ER (P = 0.027) and BCSG1 (P = 0.001) were the independent prognosis factor of breast cancer. CONCLUSION: BCSG1 is one of independent tumor marker of breast cancer, the expression of BCSG1 is closely correlated to the stage of breast cancer and the tumor size. Maybe, BCSG1 is a new prognosis factor of breast cancer.

Stage-specific expression of breast cancer-specific gene gamma-synuclein.

Gamma-synuclein (SNCG), also referred as breast cancer-specific gene 1, is the third member of a neuronal protein family synuclein. SNCG is highly expressed in human-infiltrating breast carcinomas but not expressed in normal or benign breast tissues. To evaluate the clinical relevance of SNCG expression in breast cancer progression and its correlation with clinical parameters, we analyzed SNCG expression in 79 clinical breast specimens from primary breast cancer, hyperplasia, and fibroadenoma patients by reverse transcription-PCR. The status of estrogen receptor, progesterone receptor, proliferating cell nuclear antigen, and C-erBb2 was also analyzed by immunohistochemistry. Overall SNCG mRNA expression was detectable in 38.8% of breast cancers. However, 79% of stage III/IV breast cancers were positive for SNCG expression, whereas only 15% of stage I/II breast cancers were positive for SNCG expression. In contrast, the expression of SNCG was undetectable in all benign breast lesions. The expression of SNCG was strongly correlated to the stage of breast cancer (P=0.000). This study suggests that the expression of SNCG is stage specific for breast cancer. SNCG is expected to be a useful marker for breast cancer progression and a potential target for breast cancer treatment.

Synuclein γ compromises spindle assembly checkpoint and renders resistance to antimicrotubule drugs.

Defects in the spindle assembly checkpoint (SAC) have been proposed to contribute to the chromosomal instability in human cancers. One of the major mechanisms underlying antimicrotubule drug (AMD) resistance involves acquired inactivation of SAC. Synuclein γ (SNCG), previously identified as a breast cancer-specific gene, is highly expressed in malignant cancer cells but not in normal epithelium. Here, we show that SNCG is sufficient to induce resistance to AMD-caused apoptosis in breast cancer cells and cancer xenografts. SNCG binds to spindle checkpoint kinase BubR1 and inhibits its kinase activity. Specifically, the C-terminal (Gln106-Asp127) of SNCG binds to the N-terminal TPR (tetratricopeptidelike folds) motif of BubR1. SNCG-BubR1 interaction induces a structure change of BubR1, attenuates its interaction with other key checkpoint proteins of Cdc20, and thus compromises SAC function. SNCG expression in breast cancers from patients with a neoadjuvant clinical trial showed that SNCG-positive tumors are resistant to chemotherapy-induced apoptosis. These data show that SNCG renders AMD resistance by inhibiting BubR1 activity and attenuating SAC function.

Oxygen-carbon nanotubes as a chemotherapy sensitizer for paclitaxel in breast cancer treatment.

OBJECTIVE: To study the in vivo and in vitro effects of adding oxygen carbon nanotubes (CNTs) to chemotherapy for breast cancer. METHODS: MCF-7 and SK-BR-3 breast cancer cells were co-cultured with paclitaxel and then exposed to oxygen-CNTs under hypoxic conditions. Cell proliferation, viability, and apoptosis rate were analyzed. Hypoxia-inducible factor-1 alpha (HIF-1α) expression was measured using reverse transcription-polymerase chain reaction (RT-PCR) and western blot. Nude mice were used as a human breast cancer model to explore the impact of oxygen-CNTs on the in vivo chemotherapeutic effect of paclitaxel. RESULTS: Oxygen-CNTs had no significant effects on the growth of breast cancer cells under normoxia and hypoxia. However, in the hypoxic environment, oxygen-CNTs significantly enhanced the inhibitory effect of paclitaxel on cell proliferation, as well as the apoptosis rate. Under hypoxia, downregulation of HIF-1α and upregulation of caspase-3, caspase-8, caspase-9, LC3 and Beclin-1 were observed when paclitaxel was combined with oxygen-CNT. Furthermore, addition of oxygen-CNTs to chemotherapy was found to significantly reduce tumor weight in the tumor-bearing mice model. CONCLUSIONS: Oxygen-CNTs can significantly increase the chemotherapeutic effect of paclitaxel on breast cancer cells. Oxygen-CNTs may be a potential chemosensitizer in breast cancer therapy.

Expression of synuclein gamma indicates poor prognosis of triple-negative breast cancer.

Synuclein gamma (SNCG), previously identified as breast cancer-specific gene 1, is highly expressed in malignant cells but not in normal epithelium. Studies have demonstrated that the expression of SNCG is an independent predictive marker for recurrence and metastasis in breast cancer. Triple-negative breast cancer (TNBC) is characterized by a lack of expression of both the estrogen receptor and progesterone receptor proteins as well as HER-2 and is often associated with particularly poor outcomes, early development of chemotherapy resistance, and ineffectiveness of targeted therapy. This study aimed to reveal whether SNCG-positive TNBC is more likely than SNCG-negative TNBC to have a more aggressive phenotype. One hundred and two TNBC patients were divided into two groups according to the SNCG protein expression. Clinical and biological features of SNCG-positive tumors were compared with SNCG-negative tumors. Association between survival and SNCG expression was analyzed by the Kaplan-Meier method. Hazard ratios and 95 % confidence intervals (CIs) were calculated using Cox regression. And 34.3 % TNBCs showed moderate to strong positive SNCG expression. Patients whose tumors expressed SNCG had significantly shorter disease-free survival (P = 0.013) and a higher probability of death (P = 0.002) when compared with those whose tumors did not express SNCG. The hazard ratio of metastasis or recurrence based on SNCG expression status was 2.800 (95 % CI 1.193-6.574; P = 0. 018). There was no significant correlation between SNCG expression and age, lymph node involvement, and tumor stage histological type, except tumor size which was significantly associated with SNCG expression (P = 0.032, R = 0.212). This study suggests that SNCG expression indicates [Symbol: see text]correlates with?[Symbol: see text] a much poorer prognosis of TNBC. SNCG is expected to be a useful marker for TNBC progression and a potential target for TNBC treatment.

[Biofeedback therapy for fecal incontinence in patients with mid or low rectal cancer after restorative resection].

OBJECTIVE: To investigate the efficacy of biofeedback therapy for fecal incontinence in patients with mid or low rectal cancer. METHODS: Twenty-four patients with mid or low rectal cancer received biofeedback treatments after restorative resection and therapeutic efficacy was evaluated using anorectal manometry and Vaizey and Wexner scoring systems. Eighteen inpatients without defecating difficulties were selected as control group. RESULTS: The parameters of anorectal manometry in patients with rectal cancer were significantly lower than those in the control group (P<0.01). After biofeedback therapy, the maximum squeeze pressure, resting pressure and maximum tolerated volume were significantly increased, from (118.3+/-42.9) mm Hg to (193.2+/-38.2) mm Hg, (27.8+/-9.0) mm Hg to (47.9+/-9.3) mm Hg,(97.5+/-52.8) ml to (189.1+/-39.0) ml, respectively (all P<0.01), while no significant difference in sensory threshold was observed (P=0.101). Post-treatment Vaizey (10.5+/-2.3 vs 12.9+/-2.8) and Wexner (7.5+/-2.5 vs 10.1+/-2.6) scores were significantly decreased compared with those before biofeedback (P<0.01). CONCLUSION: Biofeedback therapy can improve the anal function in patients with rectal cancer after restorative resection.

Expression of neuronal protein synuclein gamma gene as a novel marker for breast cancer prognosis.

Synucleins are emerging as central players in the fundamental neural processes and in the formation of pathologically insoluble deposits characteristic of neurodegenerative diseases. However, synuclein gamma (SNCG), previously identified as a breast cancer specific gene (BCSG1), is also highly expressed in breast carcinomas, but not expressed in normal or benign breast tissues. We analyzed SNCG gene expression in 93 clinical breast specimens and associated it with clinical outcome. Overall SNCG mRNA expression was detectable in 36% breast cancers. However, 81% of stage III/IV breast cancers were positive for SNCG expression, while only 15% of stage I/II breast cancers were positive for SNCG expression. In contrast, SNCG was undetectable in benign breast lesions. Expression of SNCG in the primary tumor also significantly associated with lymph node involvement and metastasis. There was no significant correlation between SNCG gene expression and age, menstruation, and status of ER, PR, PCNA, and HER-2. Patients whose tumors expressed SNCG had a significantly shorter DFS and a high probability of death when compared with those whose tumors did not express SNCG. The hazard ratio of metastasis or recurrence according to the SNCG status was 4.515 (95% CI, 1,188-17.154; P = 0.027). Cox multivariate analysis showed that SNCG had independent prognostic significance above and beyond conventional variables. This study suggests that the expression of SNCG is an independent predictive marker for recurrence and metastasis in breast cancer progression. SNCG is expected to be a useful marker for breast cancer progression and a potential target for breast cancer treatment.