Synergistic effect of chemo-photothermal therapy using PEGylated graphene oxide

Graphene has shown great potential both in photothermal therapy and drug delivery. Herein, we developed doxorubicin-loaded PEGylated nanographene oxide (NGO-PEG-DOX) to facilitate combined chemotherapy and photothermal therapy in one system. In this work, we studied the ablation of tumor both in vivo and in vitro by the combination of photothermal therapy and chemotherapy using this functional graphene oxide. The ability of the NGO-PEG-DOX nanoparticle to combine the local specific chemotherapy with external near-infrared (NIR) photothermal therapy significantly improved the therapeutic efficacy of cancer treatment. Compared with chemotherapy or photothermal therapy alone, the combined treatment demonstrated a synergistic effect, resulting in higher therapeutic efficacy. Furthermore, lower systematic toxicity of NGO-PEG-DOX than DOX was proved by the pathologic examination of main organs in our toxicity study.     

Theranostic vitamin E TPGS micelles of transferrin conjugation for targeted co-delivery of docetaxel and ultra bright gold nanoclusters

The aim of this work was to develop an advanced theranostic micelles of D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS), which are conjugated with transferrin for targeted co-delivery of docetaxel (DTX) as a model drug and ultra bright gold clusters (AuNC) as a model imaging agent for simultaneous cancer imaging and therapy. The theranostic micelles with and without transferrin conjugation were prepared by the solvent casting method and characterized for their particle size, polydispersity, surface chemistry, drug encapsulation efficiency, drug loading and cellular uptake efficiency. Transferrin receptors expressing MDA-MB-231-luc breast cancer cells and NIH-3T3 fibroblast cells (control cells without transferrin receptor expression) were employed as an in vitro model to access cytotoxicity of the formulations. The overexpression of transferrin receptor on the surface of MDA-MB-231-luc cells was confirmed by flow cytometry. The biodistribution study and theranostic efficacy of the micelles were investigated by using the Xenogen IVIS^® Spectrum imaging system, which includes AuNC based fluorescence imaging and luciferase induced bioluminescence imaging on MDA-MB-231-luc tumor bearing SCID mice. The IC₅₀ values demonstrated that the non-targeted and targeted micelles could be 15.31 and 71.73 folds more effective than Taxotere^® after 24 h treatment with the MDA-MB-231-luc cells. Transferrin receptor targeted delivery of such micelles was imaged in xenograft model and showed their great advantages for real-time tumor imaging and inhibition of tumor growth.     

Dipyridamole prevents triple-negative breast-cancer progression

Dipyridamole is a widely prescribed drug in ischemic disorders, and it is here investigated for potential clinical use as a new treatment for breast cancer. Xenograft mice bearing triple-negative breast cancer 4T1-Luc or MDA-MB-231T cells were generated. In these in vivo models, dipyridamole effects were investigated for primary tumor growth, metastasis formation, cell cycle, apoptosis, signaling pathways, immune cell infiltration, and serum inflammatory cytokines levels. Dipyridamole significantly reduced primary tumor growth and metastasis formation by intraperitoneal administration. Treatment with 15 mg/kg/day dipyridamole reduced mean primary tumor size by 67.5 % (p = 0.0433), while treatment with 30 mg/kg/day dipyridamole resulted in an almost a total reduction in primary tumors (p = 0.0182). Experimental metastasis assays show dipyridamole reduces metastasis formation by 47.5 % in the MDA-MB-231T xenograft model (p = 0.0122), and by 50.26 % in the 4T1-Luc xenograft model (p = 0.0292). In vivo dipyridamole decreased activated β-catenin by 38.64 % (p < 0.0001), phospho-ERK1/2 by 25.05 % (p = 0.0129), phospho-p65 by 67.82 % (p < 0.0001) and doubled the expression of IkBα (p = 0.0019), thus revealing significant effects on Wnt, ERK1/2-MAPK and NF-kB pathways in both animal models. Moreover dipyridamole significantly decreased the infiltration of tumor-associated macrophages and myeloid-derived suppressor cells in primary tumors (p < 0.005), and the inflammatory cytokines levels in the sera of the treated mice. We suggest that when used at appropriate doses and with the correct mode of administration, dipyridamole is a promising agent for breast-cancer treatment, thus also implying its potential use in other cancers that show those highly activated pathways.     

Multifunctional PEG-GO/CuS nanocomposites for near-infrared chemo-photothermal therapy

The synergistic therapy, the combination of photothermal therapy and chemotherapy, has become a potential treatment in the battles with cancer. Here, we developed a synergistic therapy tool that based on CuS nanoparticles-decorated graphene oxide functionalized with polyethylene glycol (PEG-GO/CuS) for cervical cancer treatment. The as-synthesized PEG-GO/CuS nanocomposites with excellent biocompatibility was revealed to have high storage capacity for anticancer drug of doxorubicin (Dox) and high photothermal conversion efficiency, and were effectively employed for the ablation of tumor. In addition, the therapeutic efficacy of Dox-loaded PEG-GO/CuS (PEG-GO/CuS/Dox) nanocomposites was evaluated in vitro and in vivo for cervical cancer therapy. In vitro cell cytotoxicity tests of PEG-GO/CuS/Dox demonstrate about 1.3 and 2.7-fold toxicity than PEG-GO/CuS and free Dox under 5 min irradiation with NIR laser at 1.0 W/cm², owing to both PEG-GO/CuS-mediated photothermal ablation and cytotoxicity of light-triggered Dox release. In mouse models, mouse cervical tumor growth was found to be significantly inhibited by the chemo-photothermal effect of PEG-GO/CuS/Dox nanocomposites, resulting in effective tumor reduction. Overall, compared with chemotherapy or photothermal therapy alone, the combined treatment demonstrates better therapeutic efficacy of cancer in vitro and in vivo. These findings highlight the promise of the highly versatile multifunctional nanoparticles in biomedical application.     

A fullerene-based multi-functional nanoplatform for cancer theranostic applications

Recently, nanomaterials with multiple functions, such as drug carrier, MRI and optical imaging, photothermal therapy etc, have become more and more popular in the domain of cancer research. In this study, a C60–IONP nanocomposite is synthesized via decorating iron oxide nanoparticles (IONP) onto fullerene (C60) and then functionalized by polyethylene glycol (PEG2000), giving C60–IONP–PEG with excellent stability in physiological solutions, finally folic acid (FA), a widely used tumor targeting molecule, was linked to C60–IONP–PEG in order to obtain an active tumor targeting effect to MCF-7 cells and malignant tumor in mice models. Herein, a hybrid nanoplatform with multi-functional characteristics for cancer diagnosis, photodynamic therapy (PDT), radiofrequency (RF) thermal therapy (RTT) and magnetic targeting applications was developed and explored its biofunctions in vitro and in vivo. C60–IONP–PEG–FA showed neglectable toxicity, not only served as a powerful tumor diagnostic magnetic resonance imaging (MRI) contrast agent, but also as a strong photosensitizer and powerful agent for photothermal ablation of tumor, furthermore a remarkable synergistic enhancement of PDT combination with RTT was also observed during the treatment both in vitro and in vivo. Moreover, the multi-functional nanoplatform also could selectively kill cancer cells in highly localized regions via the excellent active tumor targeting and magnetic targeted abilities. This work showed the multi-functional C60–IONP–PEG–FA nanoplatform had a great potential for cancer theranostic applications.     

Effect of anthracycline and taxane on the expression of programmed cell death ligand-1 and galectin-9 in triple-negative breast cancer

This study identified chemotherapeutic agents that up-regulate programmed cell death ligand-1 (PD-L1) and galectin-9 (Gal-9) in breast cancer cells. Immunohistochemical (IHC) staining was used to evaluate changes in PD-L1 and Gal-9 expression in the tumor tissue of triple-negative breast cancer (TNBC) patients who received anthracycline- and taxane-based neoadjuvant chemotherapy. To determine whether PD-L1 and Gal-9 expression changes were attributable directly to chemotherapeutics, MDA-MB-231 cells and HS578T cells were treated with different concentrations of anthracycline and taxane. Expression levels of PD-L1 and Gal-9 were evaluated and the activation status of NFκB in MDA-MB-231 and HS578T cells was determined to identify the PD-L1 and Gal-9 up-regulation mechanism. Three cases of increased PD-L1 expression and two of increased Gal-9 expression were observed among the TNBC patients. PD-L1 and Gal-9 expression were up-regulated by anthracycline and taxane in MDA-MB-231 cells, but not in HS578T cells. Increased nuclear levels of NFκB were observed in MDA-MB-231 cells treated with 0.5?μM epirubicin. Anthracycline and taxane up-regulated PD-L1 and Gal-9 expression in some subtypes of TNBC. This study provides useful reference data for clinical trials investigating combination treatments with immune checkpoint inhibitors and chemotherapy.     

Inhibition of metastatic tumor formation in vivo by a bacteriophage display-derived galectin-3 targeting peptide

Galectin-3 (gal-3) is involved in the metastatic cascade and interacts with the cancer-associated carbohydrate, Thomsen-Freidenreich (TF) antigen during early stages of metastatic adhesion and tumor formation. Our laboratory previously utilized bacteriophage display to select a peptide, G3-C12, with high specificity and affinity for gal-3 that was able to inhibit cancer cell adhesion. We hypothesized that G3-C12 would inhibit TF/gal-3 and gal-3/gal-3 interactions in vitro and in vivo and would moderate early steps of the metastatic cascade leading to reduced carcinogensis in vivo. To test this, adhesion of multiple breast carcinoma cell lines to purified gal-3 and a TF-mimic was measured in the presence/absence of G3-C12 resulting in an average reduction of cellular adhesion by 50 and 59 %, respectively. Sensitive optical imaging experiments were utilized to monitor the fate of intravenously injected MDA-MB-231 human breast carcinoma cells expressing luciferase into athymic nude mice in the presence/absence of G3-C12 in vivo. Intravenous administration of G3-C12 reduced lung colonization of MDA-MB-231-luciferase cells within mice by 72 % when compared to saline, whereas, control peptide treatments resulted in no significant reduction of colonization. Histologic examination of excised lung tissue, at day 70, revealed that mice treated with G3-C12 possessed 4.63 ± 3.07 tumors compared to 14.13 ± 3.56 tumors within mice treated with saline. Also, within both saline and control peptide treatment groups, 37 % of mouse lungs contained tumor thrombi, compared to 0 % within the G3-C12 treatment group. This study demonstrated that G3-C12 significantly reduced metastatic cell deposition and consequent outgrowth within vasculature of mice.     

Gamma secretase inhibitor enhances sensitivity to doxorubicin in MDA-MB-231 cells

Deregulated expression of molecular of the Notch signaling pathway is observed in malignant tumor. Notch signaling pathway is activated by a series of catalytic cleavage of the Notch receptor by gamma secretase. Gamma secretase inhibitor (GSI) have demonstrated clinical activity in patients with solid tumor. Triple negative breast cancer (TNBC) is related to poor prognosis and a high probability of lung and brain metastases. As first line therapy for TNBC, doxorubicin is partially effective in TNBC control. An understanding of the mechanisms for enhancing sensitivity to doxorubicin would be significant for future drug development. We hypothesized that a combination of cytotoxic chemotherapy doxorubicin to inhibit cell proliferation, together with GSI, would result in more effective outcome than either monotherapy alone. We treated MDA-MB-231 cell lines with doxorubicin and evaluated the monotherapy efficacy and in combination with GSI in both vitro and vivo. GSI-induced proliferation inhibition and apoptosis was achieved with an induction of PTEN and pro-apoptotic protein Bax expression and suppression of Notch-1, HES-1, CyclinD1 and anti-apoptotic protein Bcl-2. These results indicate that MDA-MB-231 cells are susceptible to a GSI, whether alone or in combination with doxorubicin, are correlated with changing of some surrogate marker. This study demonstrates practicability of combined use of GSI and doxorubicin, and together these results encourage new therapeutic method in triple negative breast cancer.     

Nano-assemblies of J-aggregates based on a NIR dye as a multifunctional drug carrier for combination cancer therapy

The combination of chemotherapy with photothermal therapy, which may lead to improved therapeutic efficacies and reduced side effects of conventional chemotherapy, would require safe drug delivery systems (DDSs) with strong near-infrared (NIR) absorbance, efficient drug loading, and effective tumor homing ability. Herein, we fabricate nano-assemblies containing J-aggregates of a NIR dye, IR825, for drug delivery and combined photothermal & chemotherapy of cancer. It is found that IR825 could be complexed with a low-molecular-weight cationic polymer polyethylenimine (PEI), forming IR825@PEI J-aggregates with greatly enhanced NIR absorbance red-shifted to 915 nm. Those nano-assemblies of J-aggregates are further modified with polyethylene glycol (PEG), obtaining IR825@PEI-PEG nano-complex which exhibits great dispersity in physiological solutions, excellent photostability, and is able to efficiently load chemotherapeutic drug doxorubicin (DOX) via a unique strategy different from drug loading in conventional amphiphilic polymer-based DDSs. In vivo animal experiments uncover that IR825@PEI-PEG/DOX upon intravenous injection into tumor-bearing mice shows rather high tumor uptake as illustrated by photoacoustic imaging. In vivo combined photothermal & chemotherapy is then carried out, demonstrating great synergistic anti-tumor therapeutic effect remarkably superior to those achieved by the respective mono-therapies. Hence, we present a novel type of nanoscale DDSs based on nano-assemblies of small molecules without involving amphiphilic polymers, promising for imaging-guided combination cancer therapy.     

吲哚胺2,3-双加氧酶1抑制剂Epacadostat联合γ干扰素诱导三阴乳腺癌细胞系凋亡

目的探讨γ干扰素(IFN-γ)与吲哚胺2,3-双加氧酶1(IDO1)抑制剂Epacadostat(Epa)联用对三阴乳腺癌细胞系4T1和MDA-MB-231凋亡作用的影响。方法IFN-γ与Epa单独或联合处理4T1和MDA-MB-231细胞48 h,流式细胞仪检测细胞凋亡;蛋白免疫印迹检测IFN-γ处理后细胞IDO1分子的表达;ELISA检测培养上清中犬尿氨酸的含量;CRISPR-Cas9法敲除IDO1分子,蛋白免疫印迹检测敲除效率。结果IFN-γ诱导三阴乳腺癌细胞系凋亡的作用较弱;IFN-γ可显著上调三阴乳腺癌细胞系IDO1的表达(P<0.001),而且细胞内Kyn的水平也显著上调(P<0.01);敲除IDO1后IFN-γ对4T1和MDA-MB-231细胞的凋亡作用大大增强;IFN-γ联用Epa促进了4T1和MDA-MB-231细胞的凋亡,大大延长了荷瘤小鼠的生存时间。结论IDO1抑制剂Epa可大大增强IFN-γ对三阴乳腺癌的治疗作用。     

内皮抑素基因转移对乳腺癌细胞生长影响的体内和离体研究

目的：探讨内皮抑素(ES)基因转移在乳腺癌抗血管新生中的作用。 方法: 通过建立逆转录病毒介导的ES基因转移系统，用ES病毒转染人乳腺癌细胞系MDA-MB-231。以聚合酶链反应（PCR）、MTT法和裸鼠成瘤实验分析ES的生物学特性及其功能。 结果： 脂质体转染与交互感染策略获得ES病毒生产细胞；以ES病毒转染MDA-MB-231细胞后，经PCR分析显示其内有ES基因整合并持续表达，其分泌的ES能明显抑制内皮细胞EA.hy926的增殖(P<0.05)，但对肿瘤细胞的离体生长无明显影响（P>0.05）；裸鼠皮下移植瘤模型表明，ES基因表达可明显抑制MDA-MB-231细胞的生长(P<0.01)；实验组的肿瘤微血管密度（MVD）和血管内皮生长因子(VEGF)表达低于对照组(P<0.05)。 结论: 逆转录病毒载体介导的ES基因在乳腺癌细胞中可有效表达，能明显抑制血管内皮细胞生长，并通过旁分泌方式抑制血管新生，具有显著的抗肿瘤生长的作用。     

Specific expression of matrix metalloproteinases 1, 3, 9 and 13 associated with invasiveness of breast cancer cells in vitro

Several matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs (TIMPs) were studied in highly invasive (MDA-MB-231) and slightly invasive (MCF-7, T47D, BT-20) breast cancer cell lines. Investigations were carried out at the protein level and/or at the mRNA level, either in cells cultured as monolayers on plastic, or in cells seeded on a thin layer of Matrigel basement membrane matrix. Analysis of MMP expression by RT-PCR showed expression of MMP-1, MMP-3, and MMP-13 in highly invasive MDA-MB-231 cells, but not in slightly invasive cell lines. The extracellular secretion of MMP-1 and MMP-3 by MDA-MB 231 cells could be also shown by ELISA. TIMP-1 and TIMP-2 mRNAs were found in all cell lines, however, the extracellular secretion of both TIMPs was much higher in MDA-MB-231 cells than in the other cell lines. When the cells were cultured on Matrigel matrix, MMP-9 expression was induced in MDA-MB-231 cells only, as assessed by RT-PCR and zymography experiments. The invasive potential of MDA-MB-231 cells evaluated in vitro through Matrigel was significantly inhibited by the MMP inhibitor BB-2516, by 25% and 50% at the concentrations of 2 × 10⁻⁶M and 10⁻⁵M, respectively. In conclusion, our data show that highly invasive MDA-MB-231 cells but not slightly invasive T47D, MCF-7 and BT-20 cells express MMP-1, MMP-3, MMP-9 and MMP-13. MMP-9 which is specifically up-regulated by cell contact to Matrigel, may play a key role in the invasiveness of MDA-MB-231 cells through basement membranes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Apatinib enhanced anti-tumor activity of cisplatin on triple-negative breast cancer through inhibition of VEGFR-2

BackgroundTriple-negative breast cancer (TNBC) was known as a fast-growing and an aggressive tumor. Cisplatin is the effective cytotoxic drug used for the treatment of TNBC. In addition, apatinib, a VEGFR2 inhibitor, exhibits antitumor activity in patients with TNBC. However, the effects of combination of apatinib with cisplatin on TNBC remain unclear. Thus, this study aimed to investigate the effects of apatinib in combination with cisplatin on MDA-MB-231 cells.MethodsImmunohistochemistry was used to detect the expression of VEGFR2. In addition, CCK-8, flow cytometric, transwell assays were used to measure the cell proliferation, apoptosis, migration and invasion, respectively. Moreover, western blotting was used to detect the expressions of Bax, active caspase 3, p-VEGFR2, p-Akt and p-mTOR.ResultsVEGFR2 was significantly upreguated in patients with TNBC. In addition, the inhibitory effects of cisplatin on the proliferation, migration and invasion of MDA-MB-231 cells were enhanced by apatinib. Moreover, apatinib increased cisplatin-induced apoptosis on MDA-MB-231 cells via increasing the level of Bax and active caspase 3 and decreasing the expression of Bcl-2. Importantly, apatinib enhanced anti-tumor effect of cisplatin on MDA-MB-231 cells via inhibiting the levels of p-VEGFR2, p-Akt and p-mTOR.ConclusionOur findings indicated that apatinib enhanced the anti-tumor effects of cisplatin on MDA-MB-231 cells via inhibition of VEGFR2. Thus, the combination of apatinib with cisplatin may serve as a potential approach in the treatment of patients with TNBC.     

MDA-MB-231细胞在乏氧条件下通过外泌体传递miR-221、miR-222增强乳腺癌细胞侵袭和迁移能力

目的探讨乳腺癌细胞MDA-MB-231在乏氧条件下分泌的外泌体对肿瘤细胞侵袭和迁移的影响。方法利用差速离心法分离外泌体,并通过动态光散射和透射电镜对外泌体的粒径、形态进行表征。通过对外泌体进行PKH26染色,进而观察肿瘤细胞对外泌体的摄取情况。应用qRT-PCR法检测肿瘤细胞及外泌体中miR-221、miR-222的含量。Transwell侵袭实验和细胞划痕实验检测MDA-MB-231细胞的侵袭和迁移能力。Western blot法检测MDA-MB-231细胞中上皮细胞-间质转化(epithelial-mesenchymal transition,EMT)相关蛋白(E-cadherin、N-cadherin和vimentin)的表达。结果MDA-MB-231细胞经乏氧处理后,其侵袭和迁移能力增强,并且N-cadherin和vimentin的表达上调;乏氧处理的肿瘤细胞分泌的外泌体通过传递miR-221、miR-222,促进MDA-MB-231细胞的EMT进展。结论MDA-MB-231细胞在乏氧条件下,可以通过外泌体传递miR-221、miR-222增加癌细胞侵袭和迁移能力。     

Co-evolution of breast-to-brain metastasis and neural progenitor cells

Brain colonization by metastatic tumor cells offers a unique opportunity to investigate microenvironmental influences on the neoplastic process. The bi-directional interplay of breast cancer cells (mesodermal origin) and brain cells (neuroectodermal origin) is poorly understood and rarely investigated. In our patients undergoing neurosurgical resection of breast-to-brain metastases, specimens from the tumor/brain interface exhibited increased active gliosis as previously described. In addition, our histological characterization revealed infiltration of neural progenitor cells (NPCs) both outside and inside the tumor margin, leading us to investigate the cellular and molecular interactions between NPCs and metastases. Since signaling by the TGF-β superfamily is involved in both developmental neurobiology and breast cancer pathogenesis, we examined the role of these proteins in the context of brain metastases. The brain-metastatic breast cancer cell line MDA-MB-231Br (231Br) expressed BMP-2 at significantly higher levels compared to its matched primary breast cancer cell line MDA-MB-231 (231). Co-culturing was used to examine bi-directional cellular effects and the relevance of BMP-2 overexpression. When co-cultured with NPCs, 231 (primary) tumor cells failed to proliferate over 15 days. However, 231Br (brain metastatic) tumor cells co-cultured with NPCs escaped growth inhibition after day 5 and proliferated, occurring in parallel with NPC differentiation into astrocytes. Using shRNA and gene knock-in, we then demonstrated BMP-2 secreted by 231Br cells mediated NPC differentiation into astrocytes and concomitant tumor cell proliferation in vitro. In xenografts, overexpression of BMP-2 in primary breast cancer cells significantly enhanced their ability to engraft and colonize the brain, thereby creating a metastatic phenotype. Conversely, BMP-2 knockdown in metastatic breast cancer cells significantly diminished engraftment and colonization. The results suggest metastatic tumor cells create a permissive neural niche by steering NPC differentiation toward astrocytes through paracrine BMP-2 signaling.     

Addition of vasopressin synthetic analogue [V<Superscript>4</Superscript>Q<Superscript>5</Superscript>]dDAVP to standard chemotherapy enhances tumour growth inhibition and impairs metastatic spread in aggressive breast tumour models

[V⁴Q⁵]dDAVP is a novel 2nd generation vasopressin analogue with robust antitumour activity against metastatic breast cancer. We recently reported that, by acting on vasopressin V2r membrane receptor present in tumour cells and microvascular endothelium, [V⁴Q⁵]dDAVP inhibits angiogenesis and metastatic progression of the disease without overt toxicity. Despite chemotherapy remaining as a primary therapeutic option for aggressive breast cancer, its use is limited by low selectivity and associated adverse effects. In this regard, we evaluated potential combinational benefits by adding [V⁴Q⁵]dDAVP to standard-of-care chemotherapy. In vitro, combination of [V⁴Q⁵]dDAVP with sub-IC₅₀ concentrations of paclitaxel or carmustine resulted in a cooperative inhibition of breast cancer cell growth in comparison to single-agent therapy. In vivo antitumour efficacy of [V⁴Q⁵]dDAVP addition to chemotherapy was first evaluated using the triple-negative MDA-MB-231 breast cancer xenograft model. Tumour-bearing mice were treated with i.v. injections of [V⁴Q⁵]dDAVP (0.3 μg/kg, thrice weekly) in combination with weekly cycles of paclitaxel (10 mg/kg i.p.). After 6 weeks of treatment, combination regimen resulted in greater tumour growth inhibition compared to monotherapy. [V⁴Q⁵]dDAVP addition was also associated with reduction of local aggressiveness, and impairment of tumour invasion and infiltration of the skin. Benefits of combined therapy were confirmed in the hormone-independent and metastatic F3II breast cancer model by combining [V⁴Q⁵]dDAVP with carmustine (25 mg/kg i.p.). Interestingly, [V⁴Q⁵]dDAVP plus cytotoxic agents severely impaired colony forming ability of tumour cells and inhibited breast cancer metastasis to lung. The present study shows that [V⁴Q⁵]dDAVP may complement conventional chemotherapy by modulating metastatic progression and early stages of microtumour establishment, and thus supports further preclinical testing of the compound for the management of aggressive breast cancer.     

NDRG1基因与乳腺癌转移的关系及其转染对乳腺癌细胞株增殖及侵袭力的影响

目的探讨NDRG1基因与乳腺癌转移的关系及其转染对乳腺癌细胞株增殖及侵袭力的影响。方法免疫组织化学SP法、即时荧光定量逆转录聚合酶链反应(real time RT-PCR)检测10例新鲜乳腺浸润性导管癌和27例石蜡包埋乳腺癌组织中NDRG1蛋白和mRNA的表达。脂质体介导NDRG1基因瞬时转染高侵袭高转移性人乳腺癌细胞株MDA-MB-231;用5-溴-2-脱氧尿苷(BrdU)掺入法、流式细胞术观察NDRG1基因转染后对细胞增殖和细胞周期的影响;细胞体外侵袭实验和迁移实验观察转染后细胞侵袭和迁移能力的变化。结果NDRG1蛋白和mRNA表达分别为:无转移的乳腺癌组织阳性率为100%(14/14)和0·82±0·14,而有转移的乳腺癌组织中为69·2%(9/13)和0·17±0·11,均明显降低;对两株细胞的检测中,高侵袭高转移的MDA-MB-231细胞株中NDRG1mRNA的表达水平(0·14±0·02)明显低于低侵袭低转移的MCF7细胞株(1·51±0·11)。NDRG1基因瞬时转染MDA-MB-231细胞后,与未转染组和pEGFP-N3组相比,pEGFP-NDRG1-N3转染组中,细胞BrdU掺入率降低,细胞周期G0/G1期比例增高,S期比例明显减低;同时细胞体外侵袭能力下降,而体外迁移能力则差异无统计学意义。结论NDRG1基因的表达与乳腺癌的转移呈负相关关系,提示该基因可望成为早期预测乳腺癌转移的分子生物学标记物之一;NDRG1基因通过脂质体转染高侵袭高转移性人乳腺癌MDA-MB-231细胞株,可抑制肿瘤细胞增殖、降低其侵袭能力,提示其可作为一个候选的肿瘤转移抑制基因,并有望成为乳腺癌基因治疗的新的候选基因。     

Ticagrelor inhibits platelet–tumor cell interactions and metastasis in human and murine breast cancer

Activated platelets promote the proliferation and metastatic potential of cancer cells. Platelet activation is largely mediated through ADP engagement of purinergic P2Y12 receptors on platelets. We examined the potential of the reversible P2Y12 inhibitor ticagrelor, an agent used clinically to prevent cardiovascular and cerebrovascular events, to reduce tumor growth and metastasis. In vitro, MCF-7, MDA-MB-468, and MDA-MB-231 human mammary carcinoma cells exhibited decreased interaction with platelets treated with ticagrelor compared to untreated platelets. Prevention of tumor cell–platelet interactions through pretreatment of platelets with ticagrelor did not improve natural killer cell-mediated tumor cell killing of K562 myelogenous leukemia target cells. Additionally, ticagrelor had no effect on proliferation of 4T1 mouse mammary carcinoma cells co-cultured with platelets, or on primary 4T1 tumor growth. In an orthotopic 4T1 breast cancer model, ticagrelor (10 mg/kg), but not clopidogrel (10 mg/kg) or saline, resulted in reduced metastasis and improved survival. Ticagrelor treatment was associated with a marked reduction in tumor cell–platelet aggregates in the lungs at 10, 30 and 60 min post-intravenous inoculation. These findings suggest a role for P2Y12-mediated platelet activation in promoting metastasis, and provide support for the use of ticagrelor in the prevention of breast cancer spread.