Identification of breast cancer-restricted antigens by antibody screening of SKBR3 cDNA library using a preselected patient's serum

Screening of a breast cancer cDNA library from SKBR3 human breast cancer cells by SEREX (serological analysis of cDNA expression library) using a preselected serum from a breast cancer patient revealed 13 genes, two of which, INT-MI-1 and INT-MI-2, encode novel gene products, while the remaining 11 genes and their products are identical with or highly homologous to known GenBank entries. Immunoscreening of the 13 clones using 20 allogeneic sera from breast cancer patients and 20 samples from age- and gender-matched healthy donors showed that lactate dehydrogenase-A (LDH-A), lactate dehydrogenase-B (LDH-B), fibulin-1, and thyroid hormone-binding protein (THBP) were recognized principally by the breast cancer patient sera, indicating the immunogenicity of these molecules in vivo. The other antigens were similarly recognized by normal and patients sera, and thus not tumor-restricted immunologically. RT-PCR analysis revealed strong expression of fibulin-1 in tumor cell lines and surgical specimen whereas in the same experimental conditions, normal tissues scored negative. Also THBP expression was found in various tumors whereas in normal tissues, its expression is restricted to the testis and, at lower levels, in ovary, liver, and spleen. In contrast, LDH-A and LDH-B were ubiquitously expressed in normal and tumor tissues, with LDH-B levels considerably lower and heterogeneous in normal samples compared to those expressed in tumor cell lines. The differential expression of fibulin-1 between the normal tissues and breast carcinoma cell lines (5/6) and surgical specimens (5/6) suggests the possible involvement of the overexpression of this extracellular matrix-associated glycoprotein in the pathogenesis of this neoplasm.     

LDH-A silencing suppresses breast cancer tumorigenicity through induction of oxidative stress mediated mitochondrial pathway apoptosis

LDH-A, as the critical enzyme accounting for the transformation from pyruvate into lactate, has been demonstrated to be highly expressed in various cancer cells and its silencing has also been approved relating to increased apoptosis in lymphoma cells. In this study, we intend to investigate the correlation between LDH-A and other clinicopathological factors of breast cancer and whether LDH-A silencing could suppress breast cancer growth, and if so the potential mechanisms. 46 breast cancer specimens were collected to study the relation between LDH-A expression and clinicopathological characteristics including menopause, tumor size, node involvement, differentiation, and pathological subtypes classified by ER, PR, and Her-2. shRNAs were designed and applied to silence LDH-A expression in breast cancer cell lines MCF-7 and MDA-MB-231. The effects of LDH-A reduction on cancer cells were studied by a series of in vitro and in vivo experiments, including cell growth assay, apoptosis evaluation, oxidative stress detection, transmission electron microscopy observation, and tumor formation assay on nude mice. LDH-A expression was found to correlate significantly with tumor size and to be independent for other clinicopathological factors. LDH-A reduction resulted in an inhibited cancer cell proliferation, elevated intracellular oxidative stress, and induction of mitochondrial pathway apoptosis. Meanwhile, the tumorigenic ability of LDH-A deficient cancer cells was significantly limited in both breast cancer xenografts. The Ki67 positive cancer cells were significantly reduced in LDH-A deficiency tumor samples, while the apoptosis ratio was enhanced. Our results suggested that LDH-A inhibition might offer a promising therapeutic strategy for breast cancer.     

Downregulation of TMPRSS4 Enhances Triple-Negative Breast Cancer Cell Radiosensitivity Through Cell Cycle and Cell Apoptosis Process Impairment

Background: Radioresistance remains a challenge for cancer radiotherapy. The present study aims to investigate the role of TMPRSS4 in triple negative breast cancer (TNBC) cell radiosensitivity. Materials and Methods: After transfection of MDA-MD-468 triple negative breast cancer cells line by using the lentivirus vector, the effect of TMPRSS4 down-regulation on TNBC radiosensitivity was evaluated by using cloning assay and CCK-8 assay. The CCK-8 assay was also used for performing cell proliferation analysis. Western blot was carried out to detect the expression of certain proteins related to cell cycle pathways (cyclin D1), cell apoptosis pathways (Bax, Bcl2, and Caspase3), DNA damage and DNA damage repair (TRF2, Ku80 , ˠH2AX) . The cell cycle and cell apoptosis were also investigated using flow cytometer analysis. Results: TMPRSS4 expression was down-regulated in MDA-MB-468 cells which enhanced MDA-MB-468 cells radiosensitivity. TMPRSS4 silencing also improved IR induced cell proliferation ability reduction and promoted cell arrested at G2/M phase mediated by 6 Gy IR associated with cyclin D1 expression inhibition. Moreover, TMPRSS4 inhibition enhanced TNBC apoptosis induced by 6 Gy IR following by over-expression of (Bax, Caspase3) and down-regulation of Bcl2 as the pro-apoptotic and anti-apoptotic proteins, respectively. Otherwise, TMPRSS4 down-regulation increases  DNA damage induced by 6 Gy IR and delays DNA damage repair respectively illustrated by downregulation of TRF2 and permanent increase of Ku80 and ˠH2AX expression at 1 h and 10 h post-IR. Conclusion: Down-regulation of TMPRSS4 increases triple negative breast cancer cell radiosensitivity and the use of TMPRSS4 inhibitor can be encouraged for improving radiotherapy effectiveness in TNBC radioresistant patients.     

癌基因c-Src抑制剂对三阴性乳腺癌的疗效评价

目的：探讨癌基因C-Src抑制剂对三阴性乳腺癌的辅助治疗作用。方法体外培养三阴性乳腺癌细胞 MDA-MB-231,并与雌激素受体（ER）、孕激素受体（PR）阳性的乳腺癌细胞 T47D 以及HER2阳性的SK-Br-3细胞做比较。用癌基因 c-Src 抑制剂来治疗三株细胞。采用 MTT 和免疫电泳的方法检测细胞的生长以及细胞信号传导通路的改变。结果c-Src抑制剂可以部分抑制 T47D 细胞生长,对三阴性乳腺癌细胞 MDA-MB-231有很明显的抑制作用。但是,对 SK-Br-3细胞的生长没有阻滞作用。进一步研究发现,是否抑制细胞生长信号传导通路决定 c-Src 抑制剂的治疗效果。HER2抑制剂可以明显抑制 SK-Br-3细胞周期与生长,而对 MDA-MB-231没有效果。结论抑制癌基因c-Src酪氨酸激酶活性对三阴性乳腺癌细胞有很好的治疗效果。     

防己诺林碱诱导人乳腺癌细胞MDA-MB-231凋亡的作用机制

目的 探讨防己诺林碱(FAN)对三阴性乳腺癌(TNBC)的抗肿瘤机制.方法 体外细胞培养人乳腺癌细胞MDA-MB-231,Alamar-Blue法检测FAN对人乳腺癌细胞MDA-MB-231的半抑制浓度(IC50);6孔板检测细胞迁移情况;细胞流式技术检测细胞凋亡情况;Western Blot检测磷脂酰肌醇-3羟基激酶(PI3K)、蛋白激酶B(AKT)、哺乳类动物雷帕霉素靶蛋白(mTOR)及磷酸化PI3K、AKT、mTOR蛋白表达.结果 FAN可抑制人乳腺癌细胞MDA-MB-231的活力(IC50为6.25μmol/L),抑制人乳腺癌细胞MDA-MB-231的迁移能力,且随着FAN浓度升高,抑制作用明显.FAN可以诱导人乳腺癌细胞MDA-MB-231凋亡,且随着FAN浓度升高,细胞凋亡率增高,同时FAN还可以下调PI3K、AKT、mTOR及磷酸化PI3K、AKT、mTOR蛋白的表达,随药物浓度的升高,其蛋白表达降低.结论 FAN可通过下调TNBC MDA-MB-231细胞凋亡PI3K/AKT/mTOR信号通路,抑制TNBC细胞的增殖、迁移,诱导细胞凋亡,可能具有抗肿瘤作用.     

The Warburg effect as a therapeutic target for bladder cancers and intratumoral heterogeneity in associated molecular targets

Bladder cancer is the 10th most common cancer worldwide. For muscle-invasive bladder cancer (MIBC), treatment includes radical cystectomy, radiotherapy, and chemotherapy; however, the outcome is generally poor. For non–muscle-invasive bladder cancer (NMIBC), tumor recurrence is common. There is an urgent need for more effective and less harmful therapeutic approaches. Here, bladder cancer cell metabolic reprogramming to rely on aerobic glycolysis (the Warburg effect) and expression of associated molecular therapeutic targets by bladder cancer cells of different stages and grades, and in freshly resected clinical tissue, is investigated. Importantly, analyses indicate that the Warburg effect is a feature of both NMIBCs and MIBCs. In two in vitro inducible epithelial-mesenchymal transition (EMT) bladder cancer models, EMT stimulation correlated with increased lactate production, the end product of aerobic glycolysis. Protein levels of lactate dehydrogenase A (LDH-A), which promotes pyruvate enzymatic reduction to lactate, were higher in most bladder cancer cell lines (compared with LDH-B, which catalyzes the reverse reaction), but the levels did not closely correlate with aerobic glycolysis rates. Although LDH-A is expressed in normal urothelial cells, LDH-A knockdown by RNAi selectively induced urothelial cancer cell apoptotic death, whereas normal cells were unaffected—identifying LDH-A as a cancer-selective therapeutic target for bladder cancers. LDH-A and other potential therapeutic targets (MCT4 and GLUT1) were expressed in patient clinical specimens; however, positive staining varied in different areas of sections and with distance from a blood vessel. This intratumoral heterogeneity has important therapeutic implications and indicates the possibility of tumor cell metabolic coupling.     

miR-26a通过调控E2F7、Myc抑制乳腺癌MDA-MB-231细胞的增殖和迁移能力

目的:研究miR-26a对乳腺癌MDA-MB-231细胞增殖和迁移能力的影响,并分析miR-26a 调控增殖与迁移的可能机制。方法:应用实时荧光定量PCR法(QPCR)检测乳腺癌细胞系和正常乳腺上皮细胞中miR-26a的表达水平,并检测三阴型乳腺癌组织及相应正常乳腺组织中miR-26a与E2F7 mRNA的表达水平。应用脂质体介导的方法,以miR-26a mimics与E2F7 siRNA瞬时转染MDA-MB-231细胞,实时荧光定量PCR法检测miR-26a表达水平,Western blot法检测E2F7、Myc蛋白的表达水平。MTT法检测MDA-MB-231细胞的增殖能力,划痕实验检测MDA-MB-231细胞迁移能力。结果:乳腺癌细胞中miR-26a的表达水平均低于正常乳腺细胞MCF-10A,且三阴型乳腺癌细胞表达水平降低最明显。三阴型乳腺癌组织中miR-26a相对于正常乳腺组织表达减低,而E2F7 mRNA表达则显著升高。miR-26a mimics转染后miR-26a表达水平显著升高,miR-26a过表达可抑制E2F7、Myc蛋白的表达;E2F7 siRNA转染后E2F7表达水平减低,Myc蛋白表达亦减低。MTT实验结果示miR-26a过表达可抑制MDA-MB-231细胞增殖,划痕实验示miR-26a过表达可抑制乳腺癌MDA-MB-231细胞迁移能力。结论:miR-26a可能通过抑制E2F7、Myc调控乳腺癌MDA-MB-231细胞的增殖与迁移能力。     

miR-25对三阴性乳腺癌细胞增殖和凋亡的影响及潜在机制

目的:研究miR-25对人三阴性乳腺癌(triple negative breast cancer,TNBC)细胞增殖和凋亡的影响,并初步探讨其可能机制。方法:在人TNBC细胞株MDA-MB-231中转染miR-25抑制性核苷酸(AS-miR-25)或对照核苷酸(NC oligo),通过MTT法和流式细胞术分别检测细胞的增殖和凋亡;采用实时定量PCR（qRT-PCR）和Western blot测量凋亡调节因子1(modulator of apoptosis 1,MOAP1)蛋白质和mRNA表达水平变化,采用双荧光素报告系统检测miR-25对MOAP1的直接调节。采用AS-miR-25和MOAP1 siRNA共转染MDA-MB-231细胞,MTT和流式细胞术检测细胞增殖、凋亡的变化。结果:下调miR-25后,MDA-MB-231细胞的增殖能力较对照明显降低（P<0.05）,凋亡显著增加（P<0.05）,MOAP1 mRNA和蛋白质表达水平显著增高（P<0.05）。双荧光素报告实验显示MOAP1受miR-25的直接调节。共转染AS-miR-25和MOAP1 siRNA可显著缓解下调miR-25引起的增殖抑制和诱导凋亡。结论:miR-25可通过下调MOAP1表达水平调节TNBC细胞增殖和凋亡,提示miR-25在TNBC恶性生物学进程中可能发挥重要促进作用。     

CIP2A is a target of bortezomib in human triple negative breast cancer cells

Introduction

Triple negative breast cancer (TNBC) is very aggressive and currently has no specific therapeutic targets, such as hormone receptors or human epidermal growth factor receptor type 2 (HER2); therefore, prognosis is poor. Bortezomib, a proteasome inhibitor, may exert efficacy in TNBC through its multiple cellular effects. Here, we tested the efficacy of bortezomib and examined the drug mechanism in breast cancer cells.

Methods

Five breast cancer cell lines: TNBC HCC-1937, MDA-MB-231, and MDA-MB-468; HER2-overexpressing MDA-MB-453; and estrogen receptor positive MCF-7 were used for in vitro studies. Apoptosis was examined by both flow cytometry and Western Blot. Signal transduction pathways in cells were assessed by Western Blot. Gene silencing was done by small interfering RNA (siRNA). In vivo efficacy of bortezomib was tested in nude mice with breast cancer xenografts. Immunohistochemical study was performed on tumor tissues from patients with TNBC.

Results

Bortezomib induced significant apoptosis, which was independent of its proteasome inhibition, in the three TNBC cell lines, but not in MDA-MB-453 or MCF-7 cells. Furthermore, cancerous inhibitor of protein phosphatase 2A (CIP2A), a cellular inhibitor of protein phosphatase 2A (PP2A), mediated the apoptotic effect of bortezomib. We showed that bortezomib inhibited CIP2A in association with p-Akt downregulation in a dose- and time-dependent manner in all sensitive TNBC cells, whereas no alterations in CIP2A expression and p-Akt were noted in bortezomib-resistant cells. Overexpression of CIP2A upregulated p-Akt and protected MDA-MB-231 and MDA-MB-468 cells from bortezomib-induced apoptosis, whereas silencing CIP2A by siRNA overcame the resistance to bortezomib-induced apoptosis in MCF-7 cells. In addition, bortezomib downregulated CIP2A mRNA but did not affect the degradation of CIP2A protein. Furthermore, bortezomib exerted in vivo antitumor activity in HCC-1937 xenografted tumors, but not in MCF-7 tumors. Bortezomib downregulated CIP2A expression in the HCC-1937 tumors but not in the MCF-7 tumors. Importantly, CIP2A expression is readily detectable in tumor samples from TNBC patients.

Conclusions

CIP2A is a major determinant mediating bortezomib-induced apoptosis in TNBC cells. CIP2A may thus be a potential therapeutic target in TNBC.     

Chalcone-3 Inhibits the Proliferation of Human Breast Cancer MDA-MB-231 Cell Line

Objective: Chalcone-3 has been shown to be cytotoxic and selective against luminal subtype breast cancer cell lines, which are suspected to occur through the mechanism of epidermal growth factor receptors (EGFR) inhibition. However, the cytotoxic effect has never been tested on cell strains from patients with triple negative breast cancer (TNBC), where EGFR expression is known to increase. This study aimed to identify the role of chalcone-3 in one of the downstream targets of EGFR as an antiproliferative agent. Methods: Chalcone-3 was examined for its effect on proliferation in human breast cancer MDA-MB-231 cell lines. The percentage of proliferation inhibition was analyzed using methyl-thiazol tetrazolium assay. Flow cytometry was used to analyze the population of cell cycle distribution and the expression of cyclin-D1 and pEGFR. Results: Chalcone-3 inhibited the proliferation of MDA-MB-231 cells in a dose and time-dependent manner with an IC50 value of 17.98±6.36 µg/mL by inducing cell cycle arrest at the G2/M phase. Flow cytometry assays showed that chalcone-3 significantly reduced the expression of pEGFR and cyclin-D1, contributing to cell cycle arrest. Conclusion: Chalcone-3 might have potential as an anti-proliferative drug to treat TNBC.     

Role of betulinic acid derivative SH-479 in triple negative breast cancer and bone microenvironment

Breast cancer has a high prevalence in the general population and is often associated with bone metastasis. Specific therapeutic targets are missing for triple negative breast cancer (TNBC), which presents some immunogenic characteristics. Betulinic acid (BA) has been reported to have some anti-tumor properties, and its modified derivative SH-479 was demonstrated to inhibit TNBC bone metastasis. The present study aimed to investigate the effect of the BA derivative SH-479 on breast cancer and bone microenvironment. The effect of BA and its derivative SH-479 on MDA-MB-231 cell proliferation was determined with the MTS method. The cytotoxicity effect of SH-479 was evaluated using the Live and Dead assay. Cell microfilament changes were observed by F-actin staining. The effects of SH-479 on PARP protein expression and cell cycle were detected by western blotting and flow cytometry, respectively. The migratory ability of breast cancer cells treated with SH-479 was determined by migration assay. The effect of SH-479 on osteoclast differentiation induced by breast cancer cells was observed using the osteoclast differentiation assay and tartrate-resistant acid phosphatase staining. The effects of SH-479 on T lymphocytes and bone marrow-derived suppressor cells (MDSCs) in bone marrow from mice were observed by flow cytometry. The results demonstrated that SH-479 significantly inhibited the proliferation of the TNBC cell line MDA-MB-231 at lower concentrations but had no significant effect on normal cells and other types of breast cancer cells for the same concentration. Furthermore, SH-479 significantly interfered with actin microfilaments in breast cancer cells but had no effect on cell apoptosis and cell cycle. In addition, SH-479 inhibited the migratory ability of breast cancer cells and the differentiation of osteoclasts induced by breast cancer cells. In bone marrow immune microenvironment, addition of SH-479 could promote the proliferation of CD4+T lymphocytes and inhibit the proliferation of MDSCs. Taken together, the findings from this study demonstrated that SH-479 inhibited the activity and migratory ability of TNBC cells and the differentiation of osteoclasts induced by TNBC and affected the bone marrow immune microenvironment. SH-479 may therefore inhibit breast cancer metastasis to bones, indicating that SH-479 may be considered as a promising drug to inhibit bone metastasis in patients with breast cancer.     

Conjugation of Cetuximab – Puromycin and Its Target-Specific Effect on Triple Negative Breast Cancer Cell Lines

Cancer is life-threatening disease and being global health problems. Chemotherapy is one of the most used therapy for cancer since many years ago. Chemotherapy is also toxic for normal cell, not specific to the target cells. Consequently, chemotherapy has various side effects. Monoclonal antibody (MAb) has been developed for specific therapy which only has killing effect in cancer cells, but the survival rate of most MAbs around 20%. Therefore, in clinical practice, MAbs administration should combine with chemotherapeutic agents. For effectiveness of therapy and to minimalize adverse effects, anticancer agent with selective cytotoxic effect on target cells is needed, the immunotoxin. Objective: This study introduces a novel approach to conjugate monoclonal antibody (Cetuximab) and toxin (Puromycin), in order to selectively inhibit proliferation of triple negative breast cancer (TNBC) and to enhance the efficacy of MAb in target cells killing. Methods: Cetuximab was conjugated with Puromycin using a linker, i.e SATP (Succinimidyl-acetylthiopropionate) and tested on triple negative breast cancer cell lines (MDA-MB-231) which expressed EGFR (epidermal growth factor receptor). Cetuximab is MAb which targets EGFR. MCF-7 was used as control cells since it has low or no EGFR expression. Cell counting were conducted as viability assay at 24 hours, 48 hours, and 72 hours after treatment. Results: The results showed significant reduction of live cells number in Conjugate 20 µg/mL cultured in MDA-MB-231 compared to MCF-7 after 24 hours, 48 hours, and 72 hours incubation. In all time period of incubation, significant reduction of MDA-MB-231 live cells number was also observed in Conjugate 20 µg/mL compared to Cetuximab 20 µg/mL. Conclusion: Synthesized conjugate showed its target-specific effect in TNBC and improved the efficacy of Cetuximab on TNBC. In the future, this conjugate can be a potential anticancer therapy in treating triple-negative breast cancer.     

miR-101、EZH2和MYC调控乳腺癌MDA-MB-231细胞增殖能力的机制

目的:研究miR-101、EZH2和MYC对乳腺癌MDA-MB-231细胞增殖的影响,并探究三者之间的调控机制。方法:以实时荧光定量PCR法检测三阴型乳腺癌组织及相应正常乳腺组织中miR-101、EZH2与MYC的表达,以及乳腺癌细胞系和正常乳腺细胞中miR-101的表达水平。以LipofectamineTM 2000将miR-101 mimics、EZH2 siRNA和MYC siRNA以及相应的阴性对照转染至MDA-MB-231细胞,Western blot法检测EZH2、MYC蛋白的表达,MTT法检测MDA-MB-231细胞的增殖能力。结果:相对于正常乳腺组织,三阴型乳腺癌组织中miR-101 mRNA的表达降低,而EZH2、MYC mRNA表达则显著升高;三阴型乳腺癌细胞中miR-101 mRNA的表达低于正常乳腺细胞MCF-10A。miR-101 mimics转染使MDA-MB-231细胞中miR-101 mRNA含量显著升高。miR-101过表达抑制EZH2、MYC的表达;EZH2敲减也抑制了MYC蛋白的表达。EZH2或MYC敲减可使miR-101 mRNA的表达显著升高。MTT实验结果示,miR-101过表达或敲减EZH2、MYC均可抑制MDA-MB-231细胞的增殖能力。结论:miR-101通过EZH2与MYC形成反馈环路调控MDA-MB-231细胞的增殖能力。     

Proliferation,migration and invasion of triple negative breast cancer cells are suppressed by berbamine via the PI3K/Akt/MDM2/p53 and PI3K/Akt/mTOR signaling pathways

Breast cancer is the second most common cause of cancer-associated mortality among women worldwide, and triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. Berbamine (BBM) is a traditional Chinese medicine used for the treatment of leukopenia without any obvious side effects. Recent reports found that BBM has anti-cancer effects. The present study aimed to investigate the effects of BBM on TNBC cell lines and the underlying molecular mechanism. MDA-MB-231 cells and MCF-7 cells, two TNBC cell lines, were treated with various concentrations of BBM. A series of bioassays including MTT, colony formation, EdU staining, apoptosis, trypan blue dye, wound healing, transwell, ELISA and western blotting assays were performed. The results showed that BBM significantly inhibited cell proliferation of MDA-MB-231 cells (P<0.05; IC₅₀=22.72 µM) and MCF-7 cells (P<0.05; IC₅₀=20.92 µM). BBM (20 µM) decreased the apoptosis ratio (percentage of absorbance compared with the control group) by 28.4±3.3% (P<0.05) in MDA-MB-231 cells, and 62.4±24.6% (P<0.05) in MCF-7 cells. In addition, BBM inhibited cell migration and invasion of TNBC cells. Furthermore, the expression levels of PI3K, phosphorylated-Akt/Akt, COX-2, LOX, MDM2 and mTOR were downregulated by BBM, and the expression of p53 was upregulated by BBM. These results indicated that BBM may suppress the development of TNBC via regulation of the PI3K/Akt/MDM2/p53 and PI3K/Akt/mTOR signal pathways. Therefore, BBM might be used as a drug candidate for the treatment of TNBC in the future.     

Potentiated effects of lactate receptor GPR81 on immune microenvironment in breast cancer

G protein-coupled receptor (GPR81), as lactate receptor, is an upstart in immune regulation, however, its mechanisms involved in tumor escape have not been fully elucidated. In this study, we explored the effects of GPR81 activation on triple-negative breast cancer (TNBC) cells and macrophages. The expression and relationship with immune infiltration of GPR81 were analyzed with TCGA database. Checkpoints and cytokines were evaluated with flow cytometry or ELISA. The TCGA-based data showed a marked decrease of GPR81 in breast cancer (BRCA) compared with normal breast, especially in the basal-like subtype. In normal mammary tissues, GPR81 had negative correlation with various immune checkpoints, nevertheless, this trend weakened accompanied with the reduction of GPR81. GPR81 stimulation had a significantly inhibitory influence on PD-L1 exposure in BT-549 and MDA-MB-231 cell lines, but not in MDA-MB-453 cell line. The pretreatment of siGPR81 to knockdown GPR81 expression resulted in a remitting of PD-L1 reduction when MDA-MB-231 cells were treated with GPR81 agonist 1. However, little effect of GPR81 activation was observed on the expression of PD-L1 on phorbol-12-myristate-13-acetate (PMA)-induced THP-1 cells. Furthermore, GPR81 agonist 1 exerted no significant impact on the secretion of cytokines in THP-1 cells. In general, it is suggested that GPR81 may facilitate immune monitoring via the reduction of PD-L1 in TNBC with glycolytic phenotype. Our results not only provide a novel insight into the effects of GPR81 on immune evasion but a potential therapy targeting GPR81 in BRCA.     

外泌体介导的Let-7a 通过下调MYC表达抑制三阴性乳腺癌细胞的恶性生物学行为

[摘要] 目的：探讨外泌体(EXO)传输Let-7a 调控MYC基因在三阴性乳腺癌（TNBC）细胞恶性生物学行为中的作用及其机制。方法：TNBC细胞MDA-MB-231 培养完成后,qPCR实验检测TNBC组织和细胞中MYC与Let-7a mRNA的表达水平,WB实验检测MYC与Let-7a 蛋白的表达水平。携Let-7a 重组慢病毒和敲除MYC的Crisper/Cas-9 系统分别转染MDA-MB-231 细胞,MTT、Transwell、划痕愈合实验检测MDA-MB-231 细胞增殖、侵袭和迁移能力。荧光素酶活性实验验证MYC和Let-7a 的作用靶点。分别在野生型和过表达Let-7a 的MDA-MB-231 细胞中分离EXO,并以透射电镜和WB实验鉴定。qPCR、WB、MTT、Transwell等实验检测两种EXO分别和MDA-MB-231 细胞共孵育后Let-7a 通过EXO影响MDA-MB-231 细胞的生物学功能。结果：Let-7a 与MYC在TNBC组织和细胞系中表达呈负相关（P<0.05）;MYC促进MDA-MB-231 细胞的增殖、迁移与侵袭,Let-7a 可以抑制MDA-MB-231 细胞的增殖、迁移与侵袭（均P<0.01）。Let-7a 通过作用于MYC基因的3''UTR 使其沉默,从而减少MYC蛋白的表达（P＜0.05）。Let-7a 由EXO包裹运输至肿瘤细胞,进而抑制MDA-MB-231 细胞的增殖、迁移与侵袭能力（P<0.05）。结论：EXO介导的Let-7a通过作用于MYC基因3’UTR区使得MYC基因沉默,从而抑制MDA-MB-231 细胞的增殖、迁移与侵袭。     

Mus81基因沉默对MDA-MB-231乳腺癌细胞增殖、凋亡及裸鼠成瘤能力的影响北大核心

目的:分析甲磺酸盐及紫外线敏感性81号基因(Mus81)在乳腺癌组织中的表达水平,观察Mus81基因敲减对三阴性乳腺癌细胞MDA-MB-231增殖、凋亡和裸鼠移植瘤形成能力的影响。方法:从TCGA数据库下载乳腺癌样本基因表达数据,应用perl及R软件整理数据筛选出每个样本Mus81基因表达量。通过慢病毒介导的小干扰RNA(short interfering RNA,siRNA)技术构建Mus81基因敲减的MDA-MB-231乳腺癌细胞系(即Mus81敲减组)和阴性对照组MDA-MB-231乳腺癌细胞系,以实时定量PCR法检测Mus81基因的敲减效率,再以MTT检测实验、克隆形成实验、细胞流式检测及实时定量PCR法检测两组MDA-MB-231细胞的生长、增殖、细胞周期分布、凋亡水平及Mus81下游基因表达水平。最后,向BALB/c裸鼠右侧腋下注射Mus81基因敲减组和阴性对照组MDA-MB-231乳腺癌细胞,观察Mus81基因沉默对MDA-MB-231细胞在裸鼠中成瘤能力的影响。结果:Mus81基因在乳腺癌组织中的平均表达量明显高于癌旁组织(P<0.05)。Mus81基因敲减组MDA-MB-231细胞中Mus81基因的表达水平明显低于阴性对照组(P<0.05),Mus81基因的敲减效率达70.7%。较之阴性对照组,Mus81基因敲减组MDA-MB-231细胞的生长速度明显减缓(P<0.05);形成的细胞克隆数也明显下降(P<0.05);细胞凋亡水平、G2/M期细胞比例则明显升高(P<0.05)。STC2等Mus81下游基因的表达水平在两组MDA-MB-231细胞间也有明显差异(P<0.05)。裸鼠成瘤实验显示,Mus81基因敲减组形成的裸鼠瘤体体积和重量均明显低于阴性对照组(P<0.05)。结论:Mus81基因在乳腺癌组织中的表达明显升高,且可能通过调控STC2等下游基因的表达促进三阴性乳腺癌细胞的生长增殖及裸鼠体内成瘤能力并抑制其凋亡,提示其可能是一个潜在的乳腺癌治疗靶点。     

lncRNA 178030.2通过TRPS1对三阴性乳腺癌细胞紫杉醇耐药的影响与机制研究

目的:探讨lncRNA 178030.2通过TRPS1对三阴性乳腺癌细胞紫杉醇耐药的影响与机制。方法:采用逐步增加剂量间歇作用的方法诱导三阴性乳腺癌紫杉醇耐药细胞系并命名为MDA-MB-231/R。采用定量PCR和Western blot检测耐药细胞和亲本细胞中lncRNA 178030.2和TRPS1的表达；应用Lipofectamine 2000将lncRNA 178030.2高表达质粒pcmv-178030.2和对照质粒pcmv转染至MDA-MB-231细胞，分别为高表达组和对照组，定量PCR检测lncRNA 178030.2水平的变化，分别用定量PCR和Western blot检测TRPS1 mRNA及蛋白水平的变化；RIP实验检测lncRNA 178030.2是否与TRPS1相结合；MTT法检测MDA-MB-231细胞对紫杉醇的敏感性及细胞增殖。应用Lipofectamine 2000将lncRNA 178030.2小干扰RNA si178030.2和对照siNC转染至MDA-MB-231/R细胞，分别为干扰组和对照组，定量PCR检测lncRNA 178030.2水平的变化，分别用定量PCR和Western blot检测TRPS1 mRNA及蛋白水平的变化；MTT法检测MDA-MB-231/R细胞对紫杉醇的敏感性及细胞增殖。应用Lipofectamine 2000将TRPS1过表达质粒pcmv-TRPS1和对照质粒pcmv转染至MDA-MB-231细胞，分别为高表达组和对照组，分别用定量PCR和Western blot检测两组细胞中TRPS1 mRNA及蛋白水平的表达情况，然后再分别应用Lipofectamine 2000将lncRNA 178030.2高表达质粒pcmv-178030.2转染入两组细胞，MTT法检测MDA-MB-231细胞对紫杉醇的敏感性及细胞增殖。结果:成功构建在3 μg/ml紫杉醇中稳定生长的三阴性乳腺癌耐药细胞系MDA-MB-231/R。定量PCR结果显示:lncRNA 178030.2在紫杉醇耐药细胞系MDA-MB-231/R中的表达明显高于在其亲本细胞MDA-MB-231中的表达；定量PCR和Western blot显示:TRPS1 mRNA和蛋白在紫杉醇耐药细胞系MDA-MB-231/R中的表达明显低于在其亲本细胞系MDA-MB-231中的表达；与对照组相比，高表达lncRNA 178030.2组的MDA-MB-231细胞中TRPS1表达下降，细胞对紫杉醇的敏感性降低，细胞增殖增强，且lncRNA 178030.2确实可以与TRPS1相结合；与对照组相比，低表达lncRNA 178030.2组的MDA-MB-231/R细胞中TRPS1表达升高，细胞对紫杉醇的敏感性升高，细胞增殖减弱；在MDA-MB-231细胞中过表达TRPS1后再过表达lncRNA 178030.2，其促进紫杉醇耐药、促进细胞增殖的作用也明显减弱。结论:lncRNA 178030.2促进三阴性乳腺癌细胞MDA-MB-231的紫杉醇耐药，促进细胞增殖，其发生机制可能与下调TRPS1的表达有关。