Overexpression of POU3F2 promotes radioresistance in triple-negative breast cancer via Akt pathway activation.

PURPOSE: POU3F2 is associated with malignant behaviors and poor prognosis in cancer. However, the function and mechanism of POU3F2 in breast cancer remain to be elucidated. Our study aimed to explore the role of POU3F2 in triple-negative breast cancer and radiotherapy. METHODS: POU3F2 expression was examined by RT-PCR and Western blot. The proliferation of cancer cells was measured by MTT assay. Migration of cancer cells was determined by Transwell assay and wound healing assay. To determine which protein interacts with POU3F2, Co-IP was performed. Survival analysis was performed based on the online database GEPIA. DNA damage after radiation was examined by Comet Assay. Radiosensitivity was evaluated with clonogenic survival assays. A tumor xenograft model was established with MDA-MB-231 breast cancer cells in BALB/c nude mice to explore the effect of POU3F2 in vivo. RESULTS: We found that the expression of POU3F2 was significantly elevated in breast cancer cells, especially in TNBC, and higher POU3F2 expression was related to poor prognosis of patients with breast cancer. Functional assays revealed that POU3F2 promoted proliferation, migration, and invasion of triple-negative breast cancer (TNBC) cells in vitro and in vivo. In addition, the knockdown of POU3F2 decreased the radioresistance of TNBC cells in vitro. Furthermore, POU3F2 could enhance the activation of the Akt pathway by interacting with ARNT2, thereby promoting proliferation and radioresistance in TNBC cells. CONCLUSIONS: Our results provide evidence that high expression of POU3F2 promotes radioresistance in triple-negative breast cancer via Akt pathway activation by interacting with ARNT2.

Tumor-targeting hydroxyapatite nanoparticles for remodeling tumor immune microenvironment (TIME) by activating mitoDNA-pyroptosis pathway in cancer.

In recent years, immunotherapy has emerged as a promising strategy for treating solid tumors, although its efficacy remains limited to a subset of patients. Transforming non-responsive "cold" tumor types into immuno-responsive "hot" ones is critical to enhance the efficacy of immune-based cancer treatments. Pyroptosis, a programmed cell death mechanism, not only effectively eliminates tumor cells but also triggers a potent inflammatory response to initiate anti-tumor immune activities. This sheds light on the potential of pyroptosis to sensitize tumors to immune therapy. Hence, it is urgent to explore and develop novel treatments (e.g., nanomedicines) which are capable of inducing pyroptosis. In this study, we constructed tumor-targeting nanoparticles (CS-HAP@ATO NPs) by loading atorvastatin (ATO) onto chondroitin sulfate (CS) modified hydroxyapatite (HAP) nanoparticles (CS-HAP). CS was strategically employed to target tumor cells, while HAP exhibited the capacity to release calcium ions (Ca2+) in response to the tumor microenvironment. Moreover, ATO disrupted the mitochondrial function, leading to intracellular energy depletion and consequential changes in mitochondrial membrane permeability, followed by the influx of Ca2+ into the cytoplasm and mitochondria. CS and HAP synergetically augmented mitochondrial calcium overload, inciting the production of substantial amount of reactive oxygen species (ROS) and the subsequent liberation of oxidized mitochondrial DNA (OX-mitoDNA). This intricate activation process promoted the assembly of inflammasomes, most notably the NLRP3 inflammasome, followed by triggering caspase-1 activation. The activated caspase-1 was able to induce gasderminD (GSDMD) protein cleavage and present the GSDM-N domain, which interacted with phospholipids in the cell membrane. Then, the cell membrane permeability was raised, cellular swelling was observed, and abundant cell contents and inflammatory mediators were released. Ultimately, this orchestrated sequence of events served to enhance the anti-tumor immunoresponse within the organism.

Cardiovascular risk factors and breast cancer incidence in a large middle-aged cohort study.

BACKGROUND: Several studies have demonstrated that cardiovascular risk factors play a role in the etiology of breast cancer. However, the combined effect of cardiovascular risk factors on the risk of breast cancer is still uncertain. METHODS: Data from the Atherosclerosis Risk in Communities (ARIC) study, a prospective cohort of middle-aged women, were used to investigate the association of individual and combined cardiovascular risk factors with breast cancer. Cox proportional hazards models were applied to calculate the hazard ratio (HR) and 95% confidence intervals (CI). RESULTS: A total of 7501 women were included. During a mean follow-up of 19.7 years, 576 women were diagnosed with breast cancer. White women and premenopausal status were independently associated with increased risk of breast cancer. Of the individual cardiovascular risk factors, only obesity was independently associated with an increased risk of breast cancer (HR 1.29, 95% CI 1.04-1.61). Compared with women without cardiovascular risk factors, women having three or greater, but not those with fewer than three cardiovascular risk factors, had a significantly higher risk of developing breast cancer (HR 1.27, 95% CI 1.06-1.53). Subgroup analyses indicated that women with three or greater cardiovascular risk factors had higher risk of breast cancer among postmenopausal Black women, but not among premenopausal Black and White women. CONCLUSIONS: Combinations of cardiovascular risk factors are associated with increased risk of breast cancer in middle-aged women, especially in postmenopausal Black women. Joint interventions to modify cardiovascular risk factors could be used to prevent breast cancer in these higher-risk individuals.

Experimental Study of Magnetic Multi-Walled Carbon Nanotube-Doxorubicin Conjugate in a Lymph Node Metastatic Model of Breast Cancer.

BACKGROUND The lymphatic system plays a significant role in the defense of a subject against breast cancer and is one of the major pathways for the metastasis of breast cancer. To improve the prognosis, many means, including surgery, radiotherapy, and chemotherapy, have been used. However, the combination of all these modalities has limited efficacy. Lymph nodes, therefore, have become an exceptionally potential target organ in cancer chemotherapy. MATERIAL AND METHODS A lymph node metastatic model of breast cancer was established in BALB/c mice. Magnetic multi-walled carbon nanotube carrier with good adsorption and lymph node-targeting capacity was prepared and conjugated with doxorubicin to make the magnetic multi-walled carbon nanotube-doxorubicin suspension. Dispersions of doxorubicin, magnetic multi-walled carbon nanotube-doxorubicin, and magnetic multi-walled carbon nanotube were injected into lymph node metastatic mice to compare their inhibitory effects on tumor cells in vivo. Inhibition of these dispersions on EMT-6 breast cancer cells was detected via MTT assay in vitro. RESULTS Although no significant difference was found between the effects of doxorubicin and magnetic multi-walled carbon nanotube-doxorubicin with the same concentration of doxorubicin on EMT-6 breast cancer cells in vitro, in terms of sizes of metastatic lymph nodes and xenograft tumors, apoptosis in metastatic lymph nodes, and adverse reactions, the magnetic multi-walled carbon nanotube-doxorubicin group differed significantly from the other groups. CONCLUSIONS The magnetic multi-walled carbon nanotube-doxorubicin clearly played an inhibitory role in lymph node metastases to EMT-6 breast cancer cells.

Use of Acellular Dermal Matrices in One-stage Implant-based Breast Reconstruction.

Implant-based breast reconstruction is the most common choice in breast cancer patients. Recently,the acellular dermal matrix (ADM) technique has been widely used in implant-based breast reconstruction in the western countries. This article briefly reviews the biological characteristics,history,types,surgical techniques,and postoperative complications of ADM.

Cancer-Associated Fibroblasts Promote Radioresistance of Breast Cancer Cells via the HGF/c-Met Signaling Pathway.

PURPOSE: Cancer-associated fibroblasts (CAFs) are an integral part of the tumor microenvironment (TME), which is involved in therapy resistance. This study aimed to investigate the role of CAFs in radiosensitivity of breast cancer cells. METHODS AND MATERIALS: The CAFs were isolated from the breast cancer tissues, and the conditioned medium was collected to culture breast cancer cells. Radiation-induced DNA damage was evaluated by immunofluorescence and western blotting. Cytokine array and enzyme-linked immunosorbent assay were performed to analyze the secretion of cytokines and growth factors. An in vitro clonogenic survival assay and in vivo xenograft mouse model were performed to determine the radiosensitivity of breast cancer cells. Finally, the expression of hepatocyte growth factor (HGF) and c-Met in the breast cancer tissues were detected by immunohistochemistry. RESULTS: The CAFs were found to secrete HGF to activate the c-Met signaling pathway, which induced epithelial-to-mesenchymal transition, growth, and radioresistance of breast cancer cells. Furthermore, radiation was observed to enhance HGF secretion by CAFs and increase c-Met expression in breast cancer cells, which led to HGF/c-Met signaling pathway activation. Moreover, radiation-induced tumor necrosis factor α (TNFα) secretion by breast cancer cells promoted CAF proliferation and HGF secretion. Additionally, HGF and c-Met high expression were associated with worse recurrence-free survival in patients with breast cancer who had received radiation therapy. CONCLUSIONS: The findings revealed that HGF and TNFα are critical for the crosstalk between breast cancer cells and CAFs in the TME and that the HGF/c-Met signaling pathway is a promising therapeutic target for radiosensitizing breast cancer.

Cancer-associated fibroblasts induce growth and radioresistance of breast cancer cells through paracrine IL-6.

In breast cancer, the most numerous stromal cells are cancer-associated fibroblasts (CAFs), which are associated with disease progression and chemoresistance. However, few studies have explored the function of CAFs in breast cancer cell radiosensitivity. Here, CAF-derived conditioned media was observed to induce breast cancer cell growth and radioresistance. CAFs secrete interleukin 6 (IL-6) which activates signal transducer and activator of transcription 3 (STAT3) signaling pathway, thus promoting the growth and radioresistance of breast cancer cells. Treatment with an inhibitor of STAT3 or an IL-6 neutralizing antibody blocked the growth and radioresistance induced by CAFs. In in vivo mouse models, tocilizumab (an IL-6 receptor monoclonal antibody) abrogated CAF-induced growth and radioresistance. Moreover, in breast cancer, a poor response to radiotherapy was associated with IL-6 and p-STAT3 expression. These results indicated that IL-6 mediates cross-talk between breast cancer cells and CAFs in the tumor microenvironment. Our results identified the IL-6/STAT3 signaling pathway as an important therapeutic target in breast cancer radiotherapy.

Mitochondria-associated ER stress evokes immunogenic cell death through the ROS-PERK-eIF2α pathway under PTT/CDT combined therapy.

Chemodynamic therapy (CDT) can effectively induce immunogenic cell death (ICD) in tumours and is thus a promising strategy for boosting the efficacy of immunotherapy. However, the mechanism by which CDT enhances ICD and lowers ICD efficiency is unknown and this restricts its clinical application. In this study, a second near-infrared (NIR-II) window irradiation-triggered hydrogen peroxide (H2O2) self-supplying nanocomposite ((Cu2Se-CaO2)@LA) was constructed. The modified lauric acid was melted by the heat energy of the NIR-II irradiation, to expose the CaO2 nanoparticles, and they then reacted with water to produce H2O2 and Ca2+. H2O2 was then converted to hydroxyl radicals by the photothermal-enhanced CDT process of the Cu2Se nanocubes. Notably, the CDT and Ca2+ overload was found to induce sequential damage to the mitochondria and endoplasmic reticulum (ER), which upregulated the PERK-mediated eIF2α phosphorylation pathway and caused subsequent ICD. NIR-II irradiation of the (Cu2Se-CaO2)@LA also increased reactive oxygen species (ROS) formation and this was sufficient to increase dendritic cell maturation, attracting cytotoxic T lymphocytes, and suppressing tumour growth in vivo. Overall, we demonstrated that an enhanced CDT strategy under NIR-II exposure and H2O2 self-supply can induce extensive ICD by inducing mitochondria-associated ER stress, which represents a highly effective and promising strategy for ICD amplification and tumour immunotherapy. STATEMENT OF SIGNIFICANCE: In this study, a second near-infrared window (NIR-II) irradiation-triggered and H2O2 self-supplying nanocomposite (named (Cu2Se-CaO2)@LA) was constructed and tested both in vitro and in vivo. These nanoparticles demonstrated promising antitumor activity as designed. Mechanistically, the nanoparticles could damage mitochondria and upregulate the PERK-mediated eIF2αphosphorylation pathway, further causing endoplasmic reticulum stress, and inducing immunogenic cell death through dendritic cell maturation and cytotoxic T lymphocyte recruitment augmented activity. This system represents a highly effective and promising strategy for enhancing tumor immunotherapy and provides new insights for future studies and design refinements.

Biodegradable hollow mesoporous organosilica nanotheranostics (HMONs) as a versatile platform for multimodal imaging and phototherapeutic-triggered endolysosomal disruption in ovarian cancer.

A major impediment in the development of nanoplatform-based ovarian cancer therapy is endo/lysosome entrapment. To solve this dilemma, a hollow mesoporous organosilica-based nanoplatform (HMON@CuS/Gd2O3) with a mild-temperature photothermal therapeutic effect and multimodal imaging abilities was successfully synthesized. HMON@CuS/Gd2O3 exhibited an appropriate size distribution, L-glutathione (GSH)-responsive degradable properties, and high singlet oxygen generation characteristics. In this study, the nanoplatform specifically entered SKOV-3 cells and was entrapped in endo/lysosomes. With a mild near infrared (NIR) power density (.5 W/cm2), the HMON@CuS/Gd2O3 nanoplatform caused lysosome vacuolation, disrupted the lysosomal membrane integrity, and exerted antitumour effects in ovarian cancer. Additionally, our in vivo experiments indicated that HMON@CuS/Gd2O3 has enhanced T1 MR imaging, fluorescence (FL) imaging (wrapping fluorescent agent), and infrared thermal (IRT) imaging capacities. Using FL/MRI/IRT imaging, HMON@CuS/Gd2O3 selectively caused mild phototherapy in the cancer region, efficiently inhibiting the growth of ovarian cancer without systemic toxicity in vivo. Taken together, the results showed that these well-synthesized nanoplatforms are likely promising anticancer agents to treat ovarian cancer and show great potential for biomedical applications.

Integrated analyses of long noncoding RNAs and mRNAs in the progression of breast cancer.

OBJECTIVE: The objective was to explore the expression and potential functions of long noncoding RNA (lncRNA) and mRNAs in human breast cancer (BC). METHODS: Differentially expressed lncRNAs and mRNAs were identified and annotated in BC tissues by using the Agilent human lncRNA assay (Agilent Technologies, Santa Clara, CA, USA) and RNA sequencing. After identification of lncRNAs and mRNAs through quantitative reverse transcription polymerase chain reaction, we conducted a series of functional experiments to confirm the effects of knockdown of one lncRNA, TCONS_00029809, on the progression of BC. RESULTS: We discovered 238 lncRNAs and 200 mRNAs that were differentially expressed in BC tissues and para-carcinoma tissue. We showed that differentially expressed mRNAs were related to biological adhesion and biological regulation and mainly enriched in cytokine-cytokine receptor interaction, metabolic pathways, and PI3K-Akt signaling pathway. We created a protein-protein interaction network to analyze the proteins enriched in these pathways. We demonstrated that silencing of TCONS_00029809 remarkably inhibited proliferation, invasion, and migration of BC cells, and accelerated their apoptosis. CONCLUSIONS: We identified a large number of differentially expressed lncRNAs and mRNAs, which provide data useful in understanding BC carcinogenesis. The lncRNA TCONS_00029809 may be involved in the development of BC.

Preparing PAMAM-NK4 nano complexes and examining their in vitro growth suppression effects in breast cancer.

BACKGROUND: This study sought to examine the suppression of the NK4 (which is a fragment that originates from the trypsin digestion of the hepatocyte growth factor) gene as mediated by new nano material polyamidoamine (PAMAM) dendrimers in the growth of breast cancer cells MDA-MB-231 and MCF-7, and the therapeutic effects in a nude mice model of transplanted tumor cell MDA-MB-231. METHODS: We built PAMAM-NK4 nano particles and detected the in vitro transfection rate. Nano complexes and blank plasmid PAMAM dendrimers were transfected to MDA-MB-231 and MCF-7 cells, respectively. The western-blotting method, MTT experiment method, and bead method were used to detect the effects of the nano complexes on NK4 protein expression, cell proliferation, and cell apoptosis. The nude mice model of transplanted tumor cell MDA-MB-231 comprised 40 nude female mice who were subject to injections. The mice were randomly divided into four groups, comprising 10 mice per group. The control, blank plasmid and treatment groups were subcutaneously injected with 0.2 mL of 0.9% NaCl (Sodium chloride) solution, 0.2 mL of plasmid solution (including 100 µg PAMAM pcDNA3.1(-) blank plasmid nano complexes) and 0.2 mL of plasmid solution (including PAMAM-NK4 100 µg) beside the tumor inoculation spot, respectively. The positive control group was intraperitoneally injected with 0.2 mL of doxorubicin solution, including 100 µg doxorubicin. Western blotting was used to detect the NK4 protein expression of the transplanted tumor tissues of the various groups. RESULTS: NK4 protein was successfully expressed in MDA-MB-231 and MCF-7 cells transfected with PAMAM-NK4 nano particles, and cell proliferation was suppressed and cell apoptosis was induced. The tumor volumes and masses of the treatment and positive control groups were obviously smaller than those of the control group. The differences were statistically significant (P<0.05). The treatment group had an obviously higher mean value of NK4 protein expression than the control group. The differences were statistically significant (P<0.05). CONCLUSIONS: PAMAM-NK4 nano complexes suppress the growth of the breast cancer cells MDA-MB-231 and MCF-7, and had a treatment effect on this tumor nude mice model of breast cancer cells.

Methylated biomarkers for breast cancer identified through public database analysis and plasma target capture sequencing.

BACKGROUND: Aberrant methylation is common during the early stage of cancer development. This study was designed to investigate DNA methylation as biomarker for breast cancer. METHODS: Public database analysis and methylation-specific whole-gene sequencing were conducted to identify methylated biomarkers that would enable early non-invasive diagnosis of breast cancer. Firstly, the data was obtained from the TCGA Database and the Blueprint Epigenome Database. Secondly, methylation-specific whole-gene sequencing was conducted in 10 female patients with early-stage breast cancer and 10 healthy female volunteers from Nanfang Hospital of Southern Medical University between March 2018 and July 2018. Thirdly, the R language was used for data analysis, and KEGG and DAVID online tool was used for annotations. RESULTS: We found that methylation levels at 13 cytosine-phosphate-guanine (CpG) sites (cg04066177, cg04281344, cg05995576, cg06221609, cg08642731, cg11388802, cg12665414, cg14557216, cg19404723, cg19457909, cg24570211, cg25818763, and cg26215982) in the malignant tissue DNA were highly comparable to those of circulating cell-free DNA (cfDNA) of breast cancer patients, but were significantly different from those of normal tissue DNA, cfDNA of healthy women, and leukocyte DNA. In addition, three CpG sites (cg04281344, cg24570211, and cg26215982) were confirmed in clinical research, which showed that the sensitivity and specificity of these CpGs as biomarkers for breast cancer were 69.4-83.7% and 85.7-88.6%, respectively. CONCLUSIONS: New biomarkers were identified and confirmed for breast cancer by comparing the methylation of tumour tissues, leukocytes, and non-plasma DNA.

MAPK4 silencing together with a PARP1 inhibitor as a combination therapy in triple­negative breast cancer cells.

Triple­negative breast cancer (TNBC) is the most common type of cancer among females worldwide and is associated with poor prognosis. Poly ADP­ribose polymerase­1 (PARP1) inhibitors are effective against TNBC with mutations in the breast cancer type 1 susceptibility protein (BRCA1) and/or BRCA2 genes; however, the development of resistance to PARP1 inhibitors limits their use. Thus, identifying strategies to overcome this resistance is urgently required. The aim of the present study was to investigate the potential function and mechanism of small interfering (si)RNA­MAPK4 (siMAPK4) in enhancing the efficacy of a PARP1 inhibitor and reducing the resistance. In the present study, data on the mRNA expression level of MAPK4 in normal breast tissues and TNBC tissues were obtained from The Cancer Genome Atlas database. The mRNA and protein expression levels of MAPK4 in normal breast cells and TNBC cells were analyzed using reverse transcription­quantitative PCR and western blotting, respectively. The phosphorylated (p) histone H2AX (γH2AX) protein expression was assessed via immunofluorescence. Cell Counting Kit­8, wound healing and TUNEL assays were used to determine the proliferative, migratory and apoptotic abilities of HCC1937 cells. MAPK4 was highly expressed in TNBC patient tissues and cell lines. Moreover, overexpression of MAPK4 could promote HCC1937 cell proliferation. Treatment of HCC1937 cells with the combination of siMAPK4 and a PARP1 inhibitor olaparib decreased their proliferation and migration and increased their apoptosis. The protein expression levels of the DNA repair­related proteins p­DNA­dependent protein kinase catalytic subunit (DNA­PK) and RAD51 recombinase (RAD51) were inhibited in the siMAPK4 and siMAPK4 + olaparib groups. However, the marker of a double­stranded break γH2AX showed increased protein expression in the siMAPK4 + olaparib group. As MAPK4 could phosphorylate AKT at threonine 308 (AKTT308), the current study restored p­AKTT308 using a constitutively active AKT plasmid (AKT­CA). p­DNA­PK and RAD51 showed high expression and γH2AX exhibited lower protein expression in the AKT­CA group. The present findings suggested that siMAPK4 can enhance the sensitivity of TNBC cells to PARP1 inhibitors.

MiR-491-5p, as a Tumor Suppressor, Prevents Migration and Invasion of Breast Cancer by Targeting ZNF-703 to Regulate AKT/mTOR Pathway.

BACKGROUND: Large amounts of microRNAs (miRNAs) have been reported to be aberrantly expressed in malignant cancers. MiR-491-5p makes a significant contribution to the inhibition of multiple cancer processes. However, the specific mechanism and function of miR-491-5p and in breast cancer (BC) is still not fully elucidated. METHODS: MiR-491-5p and ZNF-703 expressions or gene transfection effects were identified by RT-qPCR or Western blot in BC tissues or cells. And ZNF-703 expression was monitored through immunohistochemistry method. Cellular function was also confirmed using Transwell assay. Besides, AKT/mTOR pathway-related proteins were analyzed using Western blotting analysis. Moreover, the interplay between miR-491-5p and ZNF-703 was verified through dual-luciferase reporter assay. RESULTS: miR-491-5p was lowly expressed, ZNF-703 was highly expressed in BC, and miR-491-5p with low expression and ZNF-703 with high expression were associated with poor prognosis of BC patients. Results of cellular function revealed that overexpression of miR-491-5p markedly suppressed BC cell migration and invasion, and knockdown of miR-491-5p had the opposite effect. Besides, mechanism research disclosed that miR-491-5p directly could bind to ZNF-703 and downregulate ZNF-703. Moreover, we proved that ZNF-703 could prominently reverse the influences of miR-491-5p on the migration and invasion of BC cells. More importantly, the data revealed that miR-491-5p repressed AKT/mTOR pathway by ZNF-703 in BC cells. CONCLUSION: MiR-491-5p prominently suppresses the metastasis of BC cells through ZNF-703 to regulate AKT/mTOR pathway, indicating that miR-491-5p and ZNF-703 might be served as the potential therapeutic targets for BC.

PLK1 Inhibition Sensitizes Breast Cancer Cells to Radiation via Suppressing Autophagy.

PURPOSE: Polo-like kinase 1 (PLK1) is a protein kinase that is overexpressed in breast cancer and may represent an attractive target for breast cancer treatment. However, few studies have investigated the relationship between PLK1 and radiosensitivity in breast cancer. Here, we attempted to explore whether PLK1 inhibition could sensitize breast cancer cells to radiation. METHODS AND MATERIALS: Breast cancer cells were treated with PLK1 small interference RNA or the PLK1-inhibitor, GSK461364. Cell proliferation was assessed using a colony formation assay. Cell cycle analyses were performed by flow cytometry. DNA damage, autophagy, and reactive oxygen species induced by ionizing radiation were detected by immunofluorescence, Western blot, and flow cytometry, respectively. Microtubule-associated protein 1 light chain 3 alpha (LC3) puncta were detected using an immunofluorescence assay. A clonogenic survival assay was used to determine the effect of PLK1 inhibition on cell radiosensitivity. A xenograft mouse model of breast cancer cells was used to investigate the potential synergistic effects of PLK1 inhibition and irradiation in vivo. Finally, the expression of PLK1 and LC3 in the breast cancer tissues was evaluated by immunohistochemistry. RESULTS: PLK1 inhibition significantly suppressed the proliferation and increased the radiosensitivity of breast cancer cells. Pharmacologic inhibition of PLK1 by the selective inhibitor, GSK461364, enhanced the radiosensitivity of breast cancer cells in vivo (n = 4, P = .002). Mechanistically, PLK1 inhibition led to the downregulation of radiation-induced reactive oxygen species and autophagy, thereby increasing the radiosensitivity of breast cancer cells. Additionally, we detected a positive correlation between the expression of PLK1 and LC3 in human breast cancer samples (n = 102, R = 0.486, P = .005). CONCLUSIONS: Our findings indicate that PLK1 inhibition enhances the radiosensitivity of breast cancer cells in a manner associated with the suppression of radiation-induced autophagy. The inhibition of PLK1 represents a promising strategy for radiosensitizing breast cancer.

CircRNA_103809 Suppresses the Proliferation and Metastasis of Breast Cancer Cells by Sponging MicroRNA-532-3p (miR-532-3p).

Breast cancer has become one of the most serious disease threatening mankind health in the world. Accumulating studies indicated that circRNAs played an important role in the occurrence and progression of breast cancer, however, the roles of circRNA_103809 in breast cancer progression remain unclear. Therefore, in this study, we aimed to clarify the potential role and regulatory mechanism of circRNA_103809 in the development of breast cancer. Firstly, the expression level of circRNA_103809 and microRNA-532-3p (miR-532-3p) in breast cancer tissues and normal tissues were detected with the quantitative real-time polymerase chain reaction (RT-qPCR). In addition, the cell proliferation ability, metastasis ability and related pathways were identified by Cell Counting Kit-8 (CCK-8), flow cytometry, and western blot, respectively. Furthermore, the connection between circRNA_103809 and miR-532-3p was detected by dual-luciferase reporter assay. Then, our data showed that circRNA_103809 was down-regulated in breast cancer tissues in contrast to adjacent non-tumor tissues, and the relative expression level of circRNA_103809 was closely associated with distant metastasis size, TNM stage, HER-2 status and overall survival time. In addition, our in vitro assays showed that the overexpression of circRNA_103809 could significantly inhibit epithelial-mesenchymal transition (EMT) pathway, then suppress breast cancer cell proliferation and metastasis ability. Moreover, we also found that the antitumor effect induced by circRNA_103809 could be reversed with the addition of miR-532-3p mimics. Taken together, this study showed that circRNA_103809 could inhibit cell proliferation and metastasis in breast cancer by sponging miR-532-3p, and circRNA_103809 might be a prospective target of breast cancer therapy.

Clinical Value of Capecitabine-Based Combination Adjuvant Chemotherapy in Early Breast Cancer: A Meta-Analysis of Randomized Controlled Trials.

Capecitabine has consistently demonstrated high efficacy and acceptable tolerability in salvage chemotherapy for advanced breast cancer. However, there remains no consensus on its role in adjuvant chemotherapy for early breast cancer (EBC). To estimate the value of capecitabine-based combination adjuvant treatment in EBC, eight randomized controlled trials with 14,072 participants were analyzed. The efficacy and safety outcomes included disease-free survival (DFS), overall survival (OS), relapse, breast cancer-specific survival (BCSS), and grades 3-5 adverse events. Capecitabine-based combination adjuvant chemotherapy demonstrated a 16% increase in BCSS (HR = 0.84, 95% CI = 0.71-0.98, p = 0.03) in the overall analysis and a 22% improvement in DFS (HR = 0.78, 95% CI = 0.64-0.96, p = 0.02) in the hormone receptor-negative (HR-) subgroup. However, there were no significant differences in DFS (HR = 0.96, 95% CI = 0.89-1.05, p = 0.38), OS (HR = 0.91, 95% CI = 0.82-1.00, p = 0.06), or relapse between capecitabine-based and capecitabine-free combination adjuvant chemotherapy. Analogous results were observed in the subgroup analyses of HR+, HER2-, HER2+, and triple-negative EBC. Regarding safety, reduced myelosuppression and hand-foot syndrome development were observed in capecitabine-treated patients. Capecitabine-based combination adjuvant chemotherapy might provide some BCSS benefit compared with capecitabine-free regimens in EBC, but the absolute survival gain is small, and the survival benefit appears to be restricted to patients with HR- EBC, which may indicate a target population for capecitabine-based combination adjuvant chemotherapy.

Hypoxia-induced angiotensin II by the lactate-chymase-dependent mechanism mediates radioresistance of hypoxic tumor cells.

The renin-angiotensin system (RAS) is a principal determinant of arterial blood pressure and fluid and electrolyte balance. RAS component dysregulation was recently found in some malignancies and correlated with poor patient outcomes. However, the exact mechanism of local RAS activation in tumors is still unclear. Here, we find that the local angiotensin II predominantly exists in the hypoxic regions of tumor formed by nasopharyngeal carcinoma CNE2 cells and breast cancer MDA-MB-231 cells, where these tumor cells autocrinely produce angiotensin II by a chymase-dependent rather than an angiotensin converting enzyme-dependent mechanism. We further demonstrate in nasopharyngeal carcinoma CNE2 and 5-8F cells that this chymase-dependent effect is mediated by increased levels of lactate, a by-product of glycolytic metabolism. Finally, we show that the enhanced angiotensin II plays an important role in the intracellular accumulation of HIF-1α of hypoxic nasopharyngeal carcinoma cells and mediates the radiation-resistant phenotype of these nasopharyngeal carcinoma cells. Thus, our findings reveal the critical role of hypoxia in producing local angiotensin II by a lactate-chymase-dependent mechanism and highlight the importance of local angiotensin II in regulating radioresistance of hypoxic tumor cells.