T-type voltage-gated channels, Na+/Ca2+-exchanger, and calpain-2 promote photoreceptor cell death in inherited retinal degeneration.

Inherited retinal degenerations (IRDs) are a group of untreatable and commonly blinding diseases characterized by progressive photoreceptor loss. IRD pathology has been linked to an excessive activation of cyclic nucleotide-gated channels (CNGC) leading to Na+- and Ca2+-influx, subsequent activation of voltage-gated Ca2+-channels (VGCC), and further Ca2+ influx. However, a connection between excessive Ca2+ influx and photoreceptor loss has yet to be proven.Here, we used whole-retina and single-cell RNA-sequencing to compare gene expression between the rd1 mouse model for IRD and wild-type (wt) mice. Differentially expressed genes indicated links to several Ca2+-signalling related pathways. To explore these, rd1 and wt organotypic retinal explant cultures were treated with the intracellular Ca2+-chelator BAPTA-AM or inhibitors of different Ca2+-permeable channels, including CNGC, L-type VGCC, T-type VGCC, Ca2+-release-activated channel (CRAC), and Na+/Ca2+ exchanger (NCX). Moreover, we employed the novel compound NA-184 to selectively inhibit the Ca2+-dependent protease calpain-2. Effects on the retinal activity of poly(ADP-ribose) polymerase (PARP), sirtuin-type histone-deacetylase, calpains, as well as on activation of calpain-1, and - 2 were monitored, cell death was assessed via the TUNEL assay.While rd1 photoreceptor cell death was reduced by BAPTA-AM, Ca2+-channel blockers had divergent effects: While inhibition of T-type VGCC and NCX promoted survival, blocking CNGCs and CRACs did not. The treatment-related activity patterns of calpains and PARPs corresponded to the extent of cell death. Remarkably, sirtuin activity and calpain-1 activation were linked to photoreceptor protection, while calpain-2 activity was related to degeneration. In support of this finding, the calpain-2 inhibitor NA-184 protected rd1 photoreceptors.These results suggest that Ca2+ overload in rd1 photoreceptors may be triggered by T-type VGCCs and NCX. High Ca2+-levels likely suppress protective activity of calpain-1 and promote retinal degeneration via activation of calpain-2. Overall, our study details the complexity of Ca2+-signalling in photoreceptors and emphasizes the importance of targeting degenerative processes specifically to achieve a therapeutic benefit for IRDs. Video Abstract.

Correlation between androgen receptor expression and pathological response rate in pre-operative HER2-positive breast cancer patients.

PURPOSE: In this study, we aimed to explore the potential significance of AR expression in HER2-positive breast cancer patients who underwent neoadjuvant targeted therapy. Specifically, we investigated the correlation between AR expression levels and pathological complete response (pCR) rates. Our objective was to determine whether there were significant differences in pCR rates among HER2-positive breast cancer patients with different levels of AR expression. METHODS: We conducted a retrospective analysis of 258 HER-2 positive breast cancer patients who underwent neoadjuvant dual-blocked standard therapy (following the NCCN Guideline 2021) at three breast cancer centers in southwest China. We analyzed the clinicopathological features and pCR rates of these patients. The cut-off value for AR expression level was calculated as the median value of 70%. We used the chi-square test to investigate the correlation between AR expression level and pCR rate, as well as other clinicopathological features. RESULTS: Out of the 258 patients analyzed, 154 (59.69%) achieved pCR. Based on the cut-off value of 70%, AR expression level was classified as low (AR ≤ 70%) or high (AR > 70%) expression. Our analysis revealed a significant correlation between AR expression level and pCR rate in HER2-positive breast cancer patients (P = 0.031). We also found a significant association between pCR rate and clinical stage (P = 0.033) and chemotherapy regimen (P = 0.034). Furthermore, subgroup analyses showed that the pCR rate was higher in patients with high AR expression levels compared to those with low AR expression levels. Additionally, we observed that patients with an ER/AR ratio of less than 1 had a higher pCR rate than those with an ER/AR ratio greater than 1 (P = 0.038). CONCLUSION: Our study findings suggest that HER2-positive breast cancer patients with high AR expression levels may achieve higher pCR rates when treated with neoadjuvant dual-blocked therapy. Overall, our results support the idea that AR expression levels have a significant correlation with pCR rates in HER2-positive breast cancer patients receiving this particular form of treatment.

Matching Mechanism of Charge Excitation Circuit for Boosting Performance of a Rotary Triboelectric Nanogenerator.

The triboelectric nanogenerator (TENG) as an ideal low-frequency mechanical energy harvester has received extensive attention, while low output charge density limits its application. A charge excitation strategy is one of the techniques to effectively improve the surface charge density of the TENG. However, there is little in-depth research on the matching factors between the TENG and excitation circuit. Herein, a soft-contact charge excitation rotary TENG (SCER-TENG) is developed to explore the matching mechanism of different charge excitation strategies. The total output power transferred by the voltage-multiplying circuit (VMC) is 2.13 times that of the full-wave bridge rectifier, which effectively improves the output performance of the SCER-TENG. Moreover, through the established capacitor model and the theoretically calculated maximum output charge of the SCER-TENG with VMC and Zener diodes (VMC-Z), it is found that the output of the Main TENG is mainly affected by capacitors and Zener diodes. The theories have been verified by experiments. After optimization, the output charge of the Main TENG with VMC-Z (1.54 µC) is 3850% higher than that without excitation (0.04 µC). The SCER-TENG successfully harvests low-speed (2.5 m s-1) wind energy to form a self-powered system. This work has crucial instructive implications for using charge excitation strategies to improve the performance of the rotary TENG.

Socioeconomic and clinical factors affecting the proportion of breast conserving surgery in Chinese women with breast cancer.

Background: This study investigated the socioeconomic and clinical factors affecting the proportion of breast conserving surgery (BCS) in China, to improve the proportion and success rate of BCS in Chinese breast cancer patients. Methods: Six hundred and forty breast cancer patients treated with BCS were compared with 700 selected breast cancer patients (controls) treated with modified radical mastectomy (MRM) in Tianjin Medical University Cancer Institute and Hospital from January 2005 to January 2018. Patients' socioeconomic and clinical factors were collected through telephone interviews or face-to-face interviews. A total of 5,660 BCS patients were enrolled to analyze independent factors affecting initial positive margins. Chi-squared test and multiple logistic regressions were used to examine factors associated with BCS. The locoregional recurrence-free survival (LRRFS), distant metastasis-free survival (DMFS), and overall survival (OS) were calculated using the Kaplan-Meier method and the survival distribution between BCS and MRM groups was compared by log-rank test. Results: Breast cancer patients who were younger, lived in urban areas, had medical insurance, and higher levels of education and Personal income were more likely to choose BCS. We also observed that patients of Han nationality were more likely to choose BCS. Univariate analysis showed that the frozen section analysis (FSA) positive margin was significantly correlated with tumor distance from the nipple, preoperative magnetic resonance imaging (MRI) examination, T stage, pathological subtype, and lymphovascular invasion (LVI). Multivariate analysis showed the distance from the nipple, T stage, pathological subtype, and LVI, and no preoperative MRI examination were independent predictors of positive resection margins. Multivariate analysis of the correlation between MRI findings and positive resection margins revealed that tumor size, non-mass enhancement (NME), and malignant enhancement surrounding the tumor were independent predictors of positive resection margins. Conclusions: In China, socioeconomic factors largely influence the choice of surgical procedures for breast cancer patients. A gradual reduction in the influence of socioeconomic factors on the proportion of BCS is recommended. Furthermore, preoperative MRI should be encouraged in patients preparing for BCS. Clinicopathological characteristics and MRI findings are significantly associated with a positive resection margin in breast cancer patients.

Asymptomatic COVID-19 infection: diagnosis, transmission, population characteristics.

A novel coronavirus first discovered in late December 2019 has spread to many countries around the world. An increasing number of asymptomatic patients have been reported and their ability to spread the virus has been proven. This brings major challenges to the control of the transmission. The discovery and control of asymptomatic patients with COVID-19 are the key issues in future epidemic prevention and recovery. In this narrative review, we summarise the existing knowledge about asymptomatic patients and put forward detection methods that are suitable for finding such patients. Besides, we compared the characteristics and transmissibility of asymptomatic patients in different populations in order to find the best screening, diagnosis and control measures for different populations. Comprehensive preventive advice is also provided to prevent the spread of infection from asymptomatic patients.

Deciphering the performance of polo-like kinase 1 in triple-negative breast cancer progression according to the centromere protein U-phosphorylation pathway.

In general, the lack of effective therapeutic targets has led to the poor prognosis of triple-negative breast cancer (TNBC). Polo-like kinase 1 (PLK1) has been studied extensively as an effective therapeutic objective for the progression of tumor. Although the fundamental strategy and function of PLK1 in TNBC are still unclear. Here, we demonstrated that PLK1 upregulation was significantly correlated with poor prognosis in breast cancer cases utilizing the TCGA database. Additionally, ectopic PLK1 expression promoted TNBC cell proliferation, VEGFA production, and endothelial cell tube formation, whereas PLK1 knockdown induced the opposite effects. Moreover, expression of PLK1 K82R, the kinase-dead mutant of PLK1, completely inhibited PLK1-mediated cell proliferation, VEGFA production, and tube formation. Gene Set Enrichment Analysis (GSEA) showed that PLK1 expression significantly correlated with mitosis and the VEGF signaling pathway. We further observed that PLK1 phosphorylated centromere protein U (CENPU) at residue T78, thereby regulating the signaling pathway of COX-2/HIF-1α/VEGFA and the metaphase-anaphase transition of mitosis. The mechanism underlying the activity of PLK1 was also determined using a TNBC xenograft mouse model. Moreover, a PLK1 inhibitor effectively inhibited TNBC progression. Taken together, our results revealed that PLK1 plays an important role in TNBC progression via its kinase activity and phosphorylation of CENPU. Thus, PLK1 is an effective therapeutic objective for TNBC.

Chemotherapy-elicited exosomal miR-378a-3p and miR-378d promote breast cancer stemness and chemoresistance via the activation of EZH2/STAT3 signaling.

BACKGROUND: Not all breast cancer (BC) patients who receive neoadjuvant chemotherapy achieve a pathologic complete response (pCR), but the reasons for this are unknown. Previous studies have shown that exosomes produced in the tumor microenvironment in response to chemotherapy promote a chemotherapy-resistant phenotype in tumors. However, the role of BC chemotherapy-elicited exosomes in regulating chemoresistance is poorly understood. METHODS: Using commercial kits, serum exosomes were extracted from patients before neoadjuvant chemotherapy, after one cycle of chemotherapy and after four cycles of chemotherapy consisting of doxorubicin (DOX) and paclitaxel (PTX). Their miRNAs were sequenced, and the correlation between the sequencing results and chemotherapy effects was further verified by RT-qPCR using patient serum exosomes. Cell Counting Kit-8 (CCK-8) was used to detect chemosensitivity. Stemness was assessed by CD44+/CD24- population analysis and mammosphere formation assays. Chromatin immunoprecipitation (ChIP) experiments were performed to verify the binding of signal transducer and activator of transcription 3 (STAT3) to the promoter of miRNAs. RESULTS: Here, we provide clinical evidence that chemotherapy-elicited exosomal miR-378a-3p and miR-378d are closely related to the chemotherapy response and that exosomes produced by BC cells after stimulation with DOX or PTX deliver miR-378a-3p and miR-378d to neighboring cells to activate WNT and NOTCH stemness pathways and induce drug resistance by targeting Dickkopf 3 (DKK3) and NUMB. In addition, STAT3, which is enhanced by zeste homolog 2 (EZH2), bound to the promoter regions of miR-378a-3p and miR-378d, thereby increasing their expression in exosomes. More importantly, chemotherapeutic agents combined with the EZH2 inhibitor tazemetostat reversed chemotherapy-elicited exosome-induced drug resistance in a nude mouse tumor xenograft model. CONCLUSION: This study revealed a novel mechanism of acquired chemoresistance whereby chemotherapy activates the EZH2/STAT3 axis in BC cells, which then secrete chemotherapy-elicited exosomes enriched in miR-378a-3p and miR-378d. These exosomes are absorbed by chemotherapy-surviving BC cells, leading to activation of the WNT and NOTCH stem cell pathways via the targeting of DKK3 and NUMB and subsequently resulting in drug resistance. Therefore, blocking this adaptive mechanism during chemotherapy may reduce the development of chemotherapy resistance and maximize the therapeutic effect.

Chidamide Combined With Doxorubicin Induced p53-Driven Cell Cycle Arrest and Cell Apoptosis Reverse Multidrug Resistance of Breast Cancer.

The multidrug-resistant (MDR) phenotype is usually accompanied by an abnormal expression of histone deacetylase (HDAC). Given that HDAC is vital in chromatin remodeling and epigenetics, inhibiting the role of HDAC has become an important approach for tumor treatment. However, the effect of HDAC inhibitors on MDR breast cancer has not been elucidated. This study aim to demonstrate the potential of chidamide (CHI) combined with the chemotherapy drug doxorubicin (DOX) to overcome chemotherapeutic resistance of breast cancer in vitro and in vivo, laying the experimental foundation for the next clinical application. The results showed that, CHI combined with DOX showed significant cytotoxicity to MDR breast cancer cells in vitro and in vivo compared with the CHI monotherapy. The cell cycle distribution results showed that CHI caused G0/G1 cell cycle arrest and inhibited cell growth regardless of the addition of DOX. At the same time, annexin V staining and TUNEL staining results showed that CHI enhanced the number of cell apoptosis in drug-resistant cells. The western blot analysis found that p53 was activated in the CHI-treated group and combined treatment group, and then the activated p53 up-regulated p21, apoptosis regulator recombinant protein (Puma), and pro-apoptotic protein Bax, down-regulated the apoptotic proteins Bcl-xL and Bcl-2, and activated the caspase cascade to induce apoptosis.

Centromere protein U (CENPU) enhances angiogenesis in triple-negative breast cancer by inhibiting ubiquitin-proteasomal degradation of COX-2.

Triple-negative breast cancer (TNBC) is characterized by high vascularity, but anti-angiogenic therapies show poor efficacy. Centromere protein U (CENPU), a centromere component essential for mitosis, is associated with tumorigenesis in multiple cancers; however, little is known of its role in breast cancer. Here, we investigate its expression and function of promoting angiogenesis in TNBC. Immunohistochemical staining revealed high CENPU expression in TNBC tissue and high CENPU levels correlated significantly with poor distant metastasis-free and overall survival. Knockdown of CENPU in TNBC cells inhibited vascular endothelial growth factor A (VEGFA) production and significantly reduced tube formation and migration of human umbilical vein endothelial cells in vitro. In a mouse xenograft model, CENPU knockdown reduced TNBC tumor growth concomitant with a reduction in CD31 + microvessel density. Mechanistic studies revealed that CENPU promoted angiogenesis by inhibiting the ubiquitination and proteasomal degradation of cyclooxygenase-2 (COX-2), leading to increased activation of the COX-2-p-ERK-HIF-1α-VEGFA signaling pathway. Taken together, our results demonstrate a critical role for CENPU in COX-2-mediated signaling for angiogenesis, and identify a role of CENPU in regulating angiogenesis in TNBC.

GGNBP2 suppresses triple-negative breast cancer aggressiveness through inhibition of IL-6/STAT3 signaling activation.

BACKGROUND: Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, lacking effective targeted therapies, and whose underlying mechanisms are still unclear. The gene coding for Gametogenetin-binding protein (GGNBP2), also known as Zinc Finger Protein 403 (ZNF403), is located on chromosome 17q12-q23, a region known as a breast cancer susceptibility locus. We have previously reported that GGNBP2 functions as a tumor suppressor in estrogen receptor-positive breast cancer. The aim of this study was to evaluate the role and mechanisms of GGNBP2 in TNBC. METHODS: The effect of GGNBP2 on TNBC aggressiveness was investigated both in vitro and in vivo. The protein and mRNA expression levels were analyzed by western blotting and reverse transcription quantitative polymerase chain reaction, respectively. Fluorescence-activated cell sorting analysis was used to evaluate the cell cycle distribution and cell apoptosis. Immunohistochemistry was used to determine the expression of GGNBP2 in breast cancer tissues. RESULTS: We find that GGNBP2 expression decreases in TNBC tissues and is associated with the outcome of breast cancer patients. Furthermore, experimental overexpression of GGNBP2 in MDA-MB-231 and Cal51 cells suppresses cell proliferation, migration and invasion, reduces the cancer stem cell subpopulation, and promotes cell apoptosis in vitro as well as inhibits tumor growth in vivo. In these cell models, overexpression of GGNBP2 decreases the activation of IL-6/STAT3 signaling. CONCLUSION: Our data demonstrate that GGNBP2 suppresses cancer aggressiveness by inhibition of IL-6/STAT3 activation in TNBC.

Antitumor effects and mechanisms of olaparib in combination with carboplatin and BKM120 on human triple­negative breast cancer cells.

Triple­negative breast cancer (TNBC) refers to a heterogeneous group of tumors, for which there is currently a lack of targeted therapies. Poly(ADP­ribose) polymerase (PARP) inhibitors, phosphatidylinositol 3­kinase (PI3K) inhibitors and carboplatin (CBP) have demonstrated sufficient efficacy and safety for their use as individual drugs for the treatment of TNBC; however, their effects on TNBC when used as a combination have not been investigated. The primary objectives of the present study were to determine the effects of a combination of CBP, olaparib and NVP­BKM120 (BKM120), and to investigate the mechanism underlying their effects on TNBC cells. The drug combination was cytotoxic to TNBC cells, both with regards to short­term and long­term sensitivity, as determined using colony forming assays, and they exerted strong synergistic effects on MDA­MB­231 and CAL51 cell lines. All drugs affected cell cycle progression, and western blotting and immunofluorescence indicated that the the drug combination exerted its cytotoxicity via DNA damage, enhancing non­homologous end joining repair and inhibiting homologous recombination repair. These data provide a strong rationale to explore the therapeutic use of olaparib in combination with CBP and BKM120 in animal models, and later in clinical trials on patients with TNBC.

Sabutoclax, pan-active BCL-2 protein family antagonist, overcomes drug resistance and eliminates cancer stem cells in breast cancer.

Misregulation of BCL-2 family of proteins renders a survival signal to withstand cytotoxic anticancer drugs and is often found in drug resistant cells. The drug resistance phenotype is also associated with an enhancement of cancer stem cell-like (CSC) characteristics. Thus, inhibition of anti-apoptotic BCL-2 family proteins has been proposed as a possible antineoplastic strategy, and BCL-2 inhibitors are currently being clinically trailed in patients with leukemia, lymphoma or non-small cell lung cancer. However, the effects of BCL-2 inhibitors on drug resistant breast cancer have not yet been elucidated. In the present study, the effect of sabutoclax, a pan-active BCL-2 protein family antagonist, on two chemoresistant breast cancer cell lines was assessed. We found that sabutoclax showed a significant cytotoxic activity on chemoresistant breast cancer cells both in vitro and in vivo. When chemotherapeutic agents were combined with sabutoclax, strong synergistic antiproliferative effects were observed. Sabutoclax induced the blockage of BCL-2, MCL-1, BCL-xL and BFL-1, which in turn led to caspase-3/7 and caspase-9 activation and modulation of Bax, Bim, PUMA and survivin expression. Furthermore, sabutoclax effectively eliminated the CSC subpopulation and reduced sphere formation of drug-resistant cells through down-regulation of the IL-6/STAT3 signaling pathway. A similar effect was observed in a small panel of nine breast tumors ex vivo. Our findings indicate that sabutoclax partially overcomes the drug resistance phenotype of breast cancer cells by reactivation of apoptosis, mediated by the inhibition of several anti-apoptotic BCL-2 family proteins, and eliminates CSCs by abolition of the IL-6/STAT3 pathway. This offers a strong rationale to explore the therapeutic strategy of using sabutoclax alone or in combination for chemotherapy-nonresponsive breast cancer patients.