Inhibition of MCF-7 breast cancer cell proliferation and in vivo steroid sulphatase activity by 2-methoxyoestradiol-bis-sulphamate

The endogenous oestrogen metabolite, 2-methoxyoestradiol (2-MeOE2) inhibits the growth of breast cancer cells and is also a potent anti-angiogenic agent. We have previously shown that the 3-sulphamoylated derivatives of 2-methoxyoestrogens are more potent than the non-sulphamoylated compounds. In this study, we have compared the abilities of 2-methoxyoestradiol-bis-sulphamate (2-MeOE2bisMATE) and 2-MeOE2 to inhibit the growth of MCF-7 breast cancer cells. Both compounds inhibited cell growth with the IC(50) for 2-MeOE2bisMATE (0.4 microM) being six-fold lower than that for 2-MeOE2 (2.5 microM). Oestrogen sulphamates are potent inhibitors of steroid sulphatase (STS) activity. 2-MeOE2bisMATE was found to retain its STS inhibitory activity and in a placental microsome assay system it was equipotent with oestrone-3-O-sulphamate (EMATE). An in vivo study was also carried out to compare the potency of 2-MeOE2bisMATE with that of EMATE and the non-steroidal STS inhibitor, 667 coumarin sulphamate (667 COUMATE). After a single oral dose (10mg/kg) some recovery of STS activity was detected by day 3 (10%) with activity partially restored (55%) by day 7 after administration of 667 COUMATE. For the other two steroidal compounds, STS activity remained almost completely inactivated for up to 5 days with complete restoration of activity occurring by day 15. The anti-proliferative and STS inhibitory properties of 2-MeOE2bisMATE suggest that it has considerable potential for development as a novel anti-cancer drug.     

The effects of 2-methoxyoestrogen sulphamates on the in vitro and in vivo proliferation of breast cancer cells

2-Methoxyoestrogen sulphamates are a new class of compounds, which inhibit breast cancer cell proliferation and are also potent inhibitors of steroid sulphatase (STS) activity. In the present study, we have used two cell proliferation assays (MTS and AB) to identify potent new compounds in this class. Similar IC(50) values were obtained using these assays with two of the most potent compounds identified being 2-methoxyoestradiol-bis-sulphamate (2-MeOE2bisMATE) and 2-methoxyoestradiol-17beta-cyanomethyl-3-O-sulphamate (2-MeOE2CyMATE). Both compounds inhibited the proliferation of MCF-7 (ER+) and MDA-MB-231 (ER-) breast cancer cells. Using the AB assay, which allows repeat measurements of cell proliferation without killing cells, both compounds were shown to inhibit cell proliferation in an irreversible manner. As STS may be involved in the removal of the sulphamoyl moiety of these compounds, which could reduce their potency, their ability to inhibit the proliferation of MCF-7 cells transfected with the cDNA for STS was also examined. Although the STS activity was 20-fold higher in these cells than in non-transfected MCF-7 cells, no decrease in the ability of these compounds to inhibit cell proliferation was detected. To test the efficacy of these compounds in vivo, nude mice were inoculated with MCF-7 cells in Matrigel and stimulated to grow with oestradiol. Three weeks after the oral administration of 2-MeOE2bisMATE or 2-MeOE2CyMATE (20mg/kg/day, 5 days/week) tumour volumes had regressed by 52% and 22%, respectively. Both compounds also inhibited liver and tumour STS activity by >90%. The potent anti-proliferative effects of these compounds, and their ability to inhibit tumour growth and STS activity in vivo, indicates that they are suitable for development as novel therapeutic agents, which should be active against a wide range of cancers.     

2-MeOE2bisMATE induces caspase-dependent apoptosis in CAL51 breast cancer cells and overcomes resistance to TRAIL via cooperative activation of caspases

2-Methoxyoestradiol (2-MeOE2) is an endogenous oestrogen metabolite which inhibits tubulin polymerisation and has anti-tumour and anti-angiogenic activity. 2-MeOE2 induces apoptosis in a wide range of cancer cell types and has recently been demonstrated to cooperate with TRAIL to induce apoptosis in breast cancer cells. 2-Methoxyoestradiol-3,17-bis-O,O-sulphamate (2-MeOE2bisMATE) is a sulfamoylated derivative of 2-MeOE2 with enhanced activity and improved pharmacokinetic properties, and 2-MeOE2bisMATE is a promising candidate for early clinical trials. It is important, therefore, to understand the mechanisms by which 2-MeOE2bisMATE acts, and whether it retains the ability to cooperate with TRAIL. We demonstrate that 2-MeOE2bisMATE-induced apoptosis of CAL51 breast cancer cells was associated with rapid activation of caspase 3 and 9, but not caspase 8 (as measured by BID cleavage) and was completely prevented by the caspase inhibitor zVADfmk. Interfering with Fas- or TRAIL-receptor function did not prevent 2-MeOE2bisMATE-induced apoptosis. Whereas CAL51 cells were resistant to TRAIL-induced apoptosis, 2-MeOE2bisMATE and TRAIL cooperated to induce cell death. This apoptosis was associated with enhanced activation of caspases, but not increased expression of the DR5 TRAIL receptor, previously demonstrated to be induced by 2-MeOE2. Therefore, 2-MeOE2bisMATE-induced apoptosis is dependent on caspases and like 2-MeOE2, 2-MeOE2bisMATE can overcome resistance to TRAIL by stimulating activation of downstream caspases. Our results suggest that 2-MeOE2bisMATE and TRAIL might be a particularly effective combination of anti-cancer agents.     

2-Methoxyestradiol-bis-sulfamate induces apoptosis and autophagy in a tumorigenic breast epithelial cell line

In anticancer research where the focus is on finding agents that induces cell death while leaving non-tumorigenic cells less affected, a novel 2-methoxyestradiol derivative has come forth. 2-Methoxyestradiol-bis-sulfamate (2-MeOE2bisMATE) is a 2-methoxyestradiol derivative produced by bis-sulphamoylation, which possesses increased antiproliferative activity and biological availability. Several questions remain regarding the type of cell death mechanisms and possible induction of autophagy by 2-MeOE2bisMATE. The aim of this in vitro study was to investigate the cell death mechanisms exerted by 2-MeOE2bisMATE in an adenocarcinoma cell line (MCF-7) by analyzing its influence on cell growth, morphology, and possible induction of cell death. Spectrophotometry (crystal violet staining), transmission electron microscopy (TEM), light microscopy (hematoxylin and eosin staining), and fluorescent microscopy (Hoechst 33342, propidium iodide and acridine orange) were employed. Spectrophotometrical studies indicated that 2-MeOE2bisMATE decreased cell numbers to 75% in MCF-7 cells after 24 h and to 47% after 48 h of exposure. TEM demonstrated membrane blebbing, nuclear fragmentation, and chromatin condensation indicating the hallmarks of apoptosis. Light microscopy revealed the presence of several cells blocked in metaphase, and apoptotic cells were also observed. Fluorescent microscopy demonstrated increased lysosomal staining; suggesting the induction of autophagy. 2-MeOE2bisMATE shows therapeutic potential, as an, anticancer agent, and the investigation of the cell death mechanisms used by 2-MeOE2bisMATE, thus, warrants further investigation.     

The effects of 2-substituted oestrogen sulphamates on the growth of prostate and ovarian cancer cells

The human endogenous metabolite 2-methoxyoestradiol (2-MeOE2) has been shown to inhibit the proliferation of breast cancer cells. We have previously shown that sulphamoylation of a series of 2-substituted oestrogens greatly enhances their ability to inhibit breast cancer cell proliferation and induce apoptosis. In this study, we have investigated the ability of a number of 2-substituted oestrogens and their sulphamoylated derivatives to inhibit the proliferation of two prostate cancer cell lines, an ovarian cancer cell line and its drug-resistant derivatives. 2-Methoxyoestrone, 2-ethyloestrone and 2-ethyloestradiol had little effect on the growth of the cell lines tested (IC(50)>10 microM). 2-MeOE2 did inhibit the growth of the cells (IC(50)<10 microM), but to a lesser extent than any of the sulphamoylated derivatives tested (IC(50)<1.0 microM). Cells treated with the sulphamoylated derivatives became detached and rounded, displaying a characteristic apoptotic appearance. FACS analysis revealed induced G(2)/M cell cycle arrest. Treatment of cells and subsequent drug removal indicated that the effects of the drugs on the cells were irreversible. Immunoblot analysis indicated that apoptosis may be induced by phosphorylation of BCL-2. From these studies, 2-substituted oestrogen sulphamates are emerging as a potent new class of drug that may be effective against AR+/AR- prostate and ovarian tumours, and against tumours that are resistant to conventional chemotherapeutic regimens.     

The <Emphasis Type="Italic">in vitro</Emphasis> effects of 2-methoxyestradiol-bis-sulphamate on cell numbers,membrane integrity and cell morphology,and the possible induction of apoptosis and autophagy in a non-tumorigenic breast epithelial cell line

2-methoxyestradiol (2ME2) exerts estrogen receptor-independent anti-proliferative, anti-angiogenic and anti-tumor activity in vitro and in vivo. Due to its low bioavailability and rapid metabolic degradation, several analogues have been developed in recent years. 2-methoxyestradiol-bis-sulphamate (2-MeOE2bisMATE) is a bis-sulphamoylated derivative of 2ME2 with anti-proliferative activity. The aim of this study was to investigate cell signaling events induced by 2-MeOE2bisMATE in a non-tumorigenic cell line (MCF-12A) by analysing its influence on cell number, morphology and membrane integrity, and the possible induction of apoptosis and autophagy. Dose- and time-dependent studies revealed that 48 h exposure to 2-MeOE2bisMATE (0.4 μM) resulted in a decrease in cell numbers to 79%. A slight increase in the level of lactate dehydrogenase production was observed in the 2-MeOE2bisMATE-treated cells. Morphological studies revealed an increase in the number of cells in metaphase. Hallmarks of apoptosis were also found, namely nuclear fragmentation and apoptotic bodies. In addition, increased lysosomal staining was observed via fluorescent microscopy, suggesting the induction of another type of cell death, namely autophagy. Since 2-MeOE2bisMATE is regarded as a potential anti-cancer agent, it is also imperative to investigate the susceptibility of non-tumorigenic cells to its influence. The data generated from this study contributes to the understanding of the action that 2-MeOE2bisMATE exerts on the non-tumorigenic MCF-12A breast epithelial cell line.     

The effects of 2-methoxy oestrogens and their sulphamoylated derivatives in conjunction with TNF-alpha on endothelial and fibroblast cell growth, morphology and apoptosis

2-methoxyoestradiol (2-MeOE2) is a potent anti-angiogenic agent. Its 3- and 17-sulphamoylated derivatives have been demonstrated to induce G2-M cell cycle arrest and apoptosis in breast cancer cells in vitro as well as tumour regression in rats in vivo with greater potency than the parent oestrogen. To determine whether the anti-cancer properties of these derivatives can be synergistically enhanced with low-dose TNF-alpha co-treatment, we investigated the effects of these treatments in adult human fibroblasts and human umbilical vein endothelial cells (HUVECs). Treatment of fibroblasts with 0.1 microM 2-methoxyoestradiol-3,17-bis sulphamate (2-MeOE2bisMATE) but not 2-MeOE2 caused a reversible morphology change and induced G2-M arrest (from 12 to 33%) but not subsequent apoptosis. In contrast, treatment of HUVECs did not induce morphology change or G2-M arrest. Using a nucleosomal ELISA assay, we showed that TNF-alpha (20 ng/ml) combination treatment synergistically increases 0.1 microM 2-MeOE2bisMATE-induced but not 0.1 microM 2-MeOE2-induced apoptosis in HUVECs. These results suggest that TNF-alpha co-treatment may be a beneficial method of increasing the potency of 2-substituted oestrogens as anti-angiogenic agents through synergistic induction of apoptosis in endothelial cells while maintaining low cytotoxicity to fibroblasts.     

MDM2反义寡核苷酸联合紫杉醇对乳腺癌MCF-7细胞株的作用

目的:探讨靶向MDM2反义寡核苷酸(ASON)联合紫杉醇对乳腺癌MCF-7细胞株的影响。方法:合成一段与MDM2 mRNA特异性结合的反义寡核苷酸和与反义寡核苷酸有4个碱基不同的的错义寡核苷酸(MON),脂质体2000介导不同浓度的MDM2ASON转染MCF-7乳腺癌细胞系,转染的乳腺癌细胞通过1μmol/L紫杉醇药物处理后,采用RT-PCR和Western Blot方法检测MDM2 ASON联合紫杉醇的协同作用及对乳腺癌MCF-7细胞株的抑制效率,MTT观察给药后MCF-7细胞的增殖能力和药物敏感性。结果:MDM2反义寡核苷酸联合紫杉醇明显下调MDM2 mRNA及MDM2蛋白表达水平,抑制MCF-7细胞的生长,随着MDM2 ASON浓度的增加,MDM2表达越来越低,协同作用越来越强,呈剂量依赖关系,A500联合紫杉醇的协同作用最明显,MTT显示紫杉醇处理的转染MCF-7细胞增殖抑制率明显增高,A500抑制增殖作用最明显,抑制率达(13.0±0.84)%。结论:不同浓度MDM2 ASON转染后的乳腺癌MCF-7细胞,等浓度紫杉醇处理后,乳腺癌MCF-7细胞MDM2表达明显降低,细胞凋亡增加,,MDM2 ASON联合紫杉醇对MCF-7细胞有协同作用,提高了乳腺癌MCF-7细胞对紫杉醇的药物敏感性。     

Inhibition of human breast cancer cell proliferation with estradiol metabolites is as effective as with tamoxifen.

The anti-estrogenic substance tamoxifen is effective in the adjuvant therapy applied in human breast cancer. Since it partly exhibits estrogenic activity and has serious side-effects, however, pure anti-estrogenic compounds are being sought. In our experimental study, we compared the anti-proliferative effect of estradiol and 13 endogenous estradiol metabolites on human breast cancer cells with the effect of tamoxifen. We used MCF-7 and MDA-MB 231, the well-established estrogen receptor-positive and -negative cell lines. 4-hydroxytamoxifen, the active metabolite of tamoxifen, estradiol and 13 estradiol metabolites were tested in concentrations ranging from 3.1 to 100 microM. Incubation time was 4 days and cell proliferation was measured by means of the ATP chemosensitivity test. 4-hydroxytamoxifen showed an IC50 value of 27 microM and 18 microM in MCF-7 and MDA-MB 231 cells, respectively. Estradiol and its metabolites were anti-proliferative in both cell lines. A few A-ring metabolites were more effective in inhibiting cell proliferation than D-ring metabolites and the parent substance 17beta-estradiol. 4-OHE1, 2-MeOE1 and 2-MeOE2 were as effective in both cell lines as tamoxifen. For the first time it has been demonstrated that endogenous estradiol metabolites are equally anti-proliferative as tamoxifen in the context of human breast cancer cells. Since some of these metabolites exhibit no estrogenic activity, they are likely to be valuable in clinical studies of chemoprevention and adjuvant therapy of breast cancer.     

The role and proposed mechanism by which oestradiol 17β-hydroxysteroid dehydrogenase regulates breast tumour oestrogen concentrations

Synthesis of the biologically active oestrogen, oestradiol, within breast tumours makes an important contribution to the high concentrations of oestrogens which are present in malignant breast tissues. In breast tumours, oestrone is preferentially converted to oestradiol by the Type I oestradiol 17β-hydroxysteroid dehydrogenase (E2DH). Several growth factors, such as insulin-like growth factor Type I, and cytokines, such as Tumour Necrosis Factor (TNF), have been shown to stimulate E2DH activity in MCF-7 breast cancer cells. As little is known about the regulation of Type I E2DH expression and activity in other breast cancer cell lines, the expression and activity of this enzyme was examined in other oestrogen receptor positive and also oestrogen receptor negative breast cancer cell lines. As it is possible that E2DH activity may be limited by co-factor availability, the effects of exogenous co-factors on enzyme activity in these cell lines was also investigated. For T47D and BT20 breast cancer cells, the addition of exogenous co-factors was found to enhance enzyme activity. TNF, in addition to stimulating E2DH activity in MCF-7 cells, also increased activity in T47D and MDA-MB-231 cells, although to a lesser extent than in MCF-7 cells. An investigation of signalling pathways involved in the regulation of E2DH activity revealed that stimulation of both the protein kinase C (PKC) and PKA pathways may be involved in regulation of E2DH activity. As several growth factors and cytokines have now been found to be involved in regulating E2DH activity, the role that macrophages and lymphocytes have in supplying these factors and the mechanism by which these factors may stimulate tumour growth, is also reviewed.     

Functional ablation of pRb activates Cdk2 and causes antiestrogen resistance in human breast cancer cells

Estrogens are required for the proliferation of hormone dependent breast cancer cells, making estrogen receptor (ER) positive tumors amenable to endocrine therapies such as antiestrogens. However, resistance to these agents remains a significant cause of treatment failure. We previously demonstrated that inactivation of the retinoblastoma protein (pRb) family tumor suppressors causes antiestrogen resistance in MCF-7 cells, a widely studied model of estrogen responsive human breast cancers. In this study, we investigate the mechanism by which pRb inactivation leads to antiestrogen resistance. Cdk4 and cdk2 are two key cell cycle regulators that can phosphorylate and inactivate pRb, therefore we tested whether these kinases are required in cells lacking pRb function. pRb family members were inactivated in MCF-7 cells by expressing polyomavirus large tumor antigen (PyLT), and cdk activity was inhibited using the cdk inhibitors p16(INK4A) and p21(Waf1/Cip1). Cdk4 activity was no longer required in cells lacking functional pRb, while cdk2 activity was required for proliferation in both the presence and absence of pRb function. Using inducible PyLT cell lines, we further demonstrated that pRb inactivation leads to increased cyclin A expression, cdk2 activation and proliferation in antiestrogen arrested cells. These results demonstrate that antiestrogens do not inhibit cdk2 activity or proliferation of MCF-7 cells in the absence of pRb family function, and suggest that antiestrogen resistant breast cancer cells resulting from pRb pathway inactivation would be susceptible to therapies that target cdk2.     

TLK1B mediated phosphorylation of Rad9 regulates its nuclear/cytoplasmic localization and cell cycle checkpoint

Breast cancer is the most frequent malignancy in women and drug resistance is the major obstacle for its successful chemotherapy. In the present study, we analyzed the involvement of an oncofetal gene, sal-like 4 (SALL4), in the tumor proliferation and drug resistance of human breast cancer. Our study showed that SALL4 was up-regulated in the drug resistant breast cancer cell line, MCF-7/ADR, compared to the other five cell lines. We established the lentiviral system expressing short hairpin RNA to knockdown SALL4 in MCF-7/ADR cells. Down-regulation of SALL4 inhibited the proliferation of MCF-7/ADR cells and induced the G1 phase arrest in cell cycle, accompanied by an obvious reduction of the expression of cyclinD1 and CDK4. Besides, down-regulating SALL4 can re-sensitize MCF-7/ADR to doxorubicin hydrochloride (ADMh) and had potent synergy with ADMh in MCF-7/ADR cells. Depletion of SALL4 led to a decrease in IC50 for ADMh and an inhibitory effect on the ability to form colonies in MCF-7/ADR cells. With SALL4 knockdown, ADMh accumulation rate of MCF-7/ADR cells was increased, while the expression of BCRP and c-myc was significantly decreased. Furthermore, silencing SALL4 also suppressed the growth of the xenograft tumors and reversed their resistance to ADMh in vivo. SALL4 knockdown inhibits the growth of the drug resistant breast cancer due to cell cycle arrest and reverses tumor chemo-resistance through down-regulating the membrane transporter, BCPR. Thus, SALL4 has potential as a novel target for the treatment of breast cancer.     

MiR-5047在乳腺癌细胞增殖迁移中的作用及表达调控*

探讨miR-5047在乳腺癌细胞中的表达及其在乳腺癌细胞增殖和迁移中的作用,并明确地西他滨在miR-5047表达调控中的作用。通过实时荧光定量PCR(qRT-PCR)检测人乳腺癌细胞系和正常乳腺上皮细胞MCF10A中miR-5047的表达水平;将miR-5047模拟物(mimic),阴性对照(NC)分别转染至MDA-MB-231和MCF7细胞,经平板克隆实验、MTT实验、划痕愈合实验检测乳腺癌细胞的增殖和迁移能力,通过qRT-PCR和Western blot检测相关基因表达及蛋白水平。使用浓度5 μmol/L和10 μmol/L的地西他滨分别处理MDA-MB-231和MCF-7细胞,经qRT-PCR检测不同浓度和处理时间条件下地西他滨对miR-5047表达的影响。同时,通过形态观察和Western blot检测地西他滨对乳腺癌细胞上皮间质转化的影响。与正常乳腺上皮细胞MCF-10A相比,miR-5047在乳腺癌细胞中表达均显著下调。miR-5047过表达可显著抑制乳腺癌细胞的增殖和迁移,促进上皮细胞标志物E-cadherin的表达,抑制间质细胞标志物Vimentin的表达。不同浓度地西他滨处理MDA-MB-231和MCF7细胞后,miR-5047表达均增强,且10 μmol/L作用48 h效果最显著。地西他滨可诱导MDA-MB-231细胞向上皮样转变。miR-5047在乳腺癌细胞系中表达显著下调,过表达miR-5047可抑制乳腺癌细胞的增殖和迁移,地西他滨可促进乳腺癌细胞中miR-5047的表达,并诱导细胞向上皮样转变。     

Steroid sulphatase inhibitors for breast cancer therapy

In contrast to aromatase inhibitors, which are now in clinical use, the development of steroid sulphatase (STS) inhibitors for breast cancer therapy is still at an early stage. STS regulates the formation of oestrone from oestrone sulphate (E1S) but also controls the hydrolysis of dehydroepiandrosterone sulphate (DHEA-S). DHEA can be reduced to 5-androstenediol (Adiol), a steroid with potent oestrogenic properties. The active pharmacophore for potent STS inhibitors has now been identified, i.e. a sulphamate ester group linked to an aryl ring. This has led to the development of a number of STS inhibitors, some of which are due to enter Phase I trials in the near future. Such first generation inhibitors include the tricyclic coumarin-based 667 COUMATE. Aryl sulphamates, such as 667 COUMATE, are taken up by red blood cells (rbc), binding to carbonic anhydrase II (CA II), and transit the liver without undergoing first-pass inactivation. 667 COUMATE is also a potent inhibitor of CA II activity with an IC₅₀ of 17 nM. Second generation STS inhibitors, such as 2-methoxyoestradiol bis-sulphamate (2-MeOE2bisMATE), in addition to inhibiting STS activity, also inhibit the growth of oestrogen receptor negative (ER⁻) tumours in mice and are anti-angiogenic. As the active pharmacaphores for the inhibition of aromatase and STS are now known it may be possible to develop third generation inhibitors that are capable of inhibiting the activities of both enzymes. Whilst exploring the potential of such a strategy it was discovered that 667 COUMATE possessed weak aromatase inhibitory properties with an IC₅₀ of 300 nM in JEG-3 cells. The identification of potent STS inhibitors will allow the therapeutic potential of this new class of drug to be explored in post-menopausal women with hormone-dependent breast cancer. Second generation inhibitors, such as 2-MeOE2bisMATE, which also inhibit the growth of ER⁻ tumours should be active against a wide range of cancers.     

IL-7 splicing variant IL-7δ5 induces human breast cancer cell proliferation via activation of PI3K/Akt pathway

Various tumor cells express interleukin 7 (IL-7) and IL-7 variants. IL-7 has been confirmed to stimulate solid tumor cell proliferation. However, the effect of IL-7 variants on tumor cell proliferation remains unclear. In this study, we evaluated the role of IL-7δ5 (an IL-7 variant lacking exon 5) on proliferation and cell cycle progression of human MDA-MB-231 and MCF-7 breast cancer cells. The results showed that IL-7δ5 promoted cell proliferation and cell cycle progression from G1 phase to G2/M phase, associated with upregulation of cyclin D1 expression and the downregulation of p27(kip1) expression. Mechanistically, we found that IL-7δ5 induced the activation of Akt. Inhibition of PI3K/Akt pathway by LY294002 reversed the proliferation and cell cycle progression of MDA-MB-231 and MCF-7 cells induced by IL-7δ5. In conclusion, our findings demonstrate that IL-7δ5 variant induces human breast cancer cell proliferation and cell cycle progression via activation of PI3K/Akt pathway. Thus, IL-7δ5 may be a potential target for human breast cancer therapeutics intervention.     

RNA甲基化酶WTAP对乳腺癌MCF-7和耐阿霉素MCF-7/ADR细胞迁移的影响

为了深入探讨乳腺癌治疗耐药的发生机制并寻找乳腺癌治疗耐药的潜在治疗手段,我们以乳腺癌MCF-7和耐阿霉素MCF-7/ADR细胞为研究对象,研究RNA甲基化酶WTAP对其迁移的影响。MTT试验发现阿霉素对MCF-7细胞活力的抑制作用大于对MCF-7/ADR细胞的抑制作用。qPCR和western-blot试验发现WTAP在耐阿霉素细胞MCF-7/ADR中高表达,同时transwell试验发现在MCF-7细胞中增加WTAP的表达对MCF-7细胞的迁移没有影响,而在MCF-7/ADR细胞中敲低WTAP的表达会抑制MCF-7/ADR细胞的迁移。western-blot试验进一步证明了这一作用是通过抑制上皮间质转化(EMT)来发挥的。这一发现有助于为乳腺癌的临床治疗提供新的理论依据并为乳腺癌的治疗提供新的策略。     

Effects of thyroid hormones on human breast cancer cell proliferation

The involvement of estrogens in breast cancer development and growth has been well established. However, the effects of thyroid hormones and their combined effects with estrogens are not well studied. We investigated the response of human breast cancer cells to thyroid hormone, particularly the role of T3 in mediating cell proliferation and gene expression. We demonstrated that 17β-estradiol (E2) or triiodothyronine (T3) promoted cell proliferation in a dose-dependent manner in both MCF-7 and T47-D cell lines. The E2- or T3-dependent cell proliferation was suppressed by co-administration of the ER antagonist ICI. We also demonstrated that T3 could enhance the effect of E2 on cell proliferation in T47-D cells. Using an estrogen response element (ERE)-mediated luciferase assay, we determined that T3 was able to induce the activation of ERE-mediated gene expression in MCF-7 cells, although the effects were much weaker than that induced by E2. These results suggest that T3 can promote breast cancer cell proliferation and increase the effect of E2 on cell proliferation in some breast cancer cell lines and thus that T3 may play a role in breast cancer development and progression.