Suppression of triple-negative breast cancer metastasis by pan-DAC inhibitor panobinostat via inhibition of ZEB family of EMT master regulators

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype that lacks effective targeted therapies. The epithelial-to-mesenchymal transition (EMT) is a key contributor in the metastatic process. We previously showed the pan-deacetylase inhibitor LBH589 induces CDH1 expression in TNBC cells, suggesting regulation of EMT. The purpose of this study was to examine the effects of LBH589 on the metastatic qualities of TNBC cells and the role of EMT in this process. A panel of breast cancer cell lines (MCF-7, MDA-MB-231, and BT-549), drugged with LBH589, was examined for changes in cell morphology, migration, and invasion in vitro. The effect on in vivo metastasis was examined using immunofluorescent staining of lung sections. EMT gene expression profiling was used to determine LBH589-induced changes in TNBC cells. ZEB overexpression studies were conducted to validate requirement of ZEB in LBH589-mediated proliferation and tumorigenesis. Our results indicate a reversal of EMT by LBH589 as demonstrated by altered morphology and altered gene expression in TNBC. LBH589 was shown to be a more potent inhibitor of EMT than other HDAC inhibitors, SAHA and TMP269. Additionally, we found that LBH589 inhibits metastasis of MDA-MB-231 cells in vivo. These effects of LBH589 were mediated in part by inhibition of ZEB, as overexpression of ZEB1 or ZEB2 mitigated the effects of LBH589 on MDA-MB-231 EMT-associated gene expression, migration, invasion, CDH1 expression, and tumorigenesis. These data indicate therapeutic potential of LBH589 in targeting EMT and metastasis of TNBC.     

The pan-DAC inhibitor LBH589 is a multi-functional agent in breast cancer cells: cytotoxic drug and inducer of sodium-iodide symporter (NIS)

New drugs with anti-tumor activity, also able to modify the expression of selected molecules, are under evaluation in breast cancer which is becoming resistant to conventional treatment, or in metastatic disease. The sodium-iodide symporter (NIS), which mediates iodide uptake into thyroid cells, and is the molecular basis of radioiodine imaging and therapy in thyroid cancer, is also expressed in a large portion of breast tumors. Since NIS expression in breast cancer is not sufficient for a significant iodide uptake, drugs able to induce its expression and correct function are under evaluation. In the present study, we report for the first time that the pan-deacetylase (DAC) inhibitor LBH589 (panobinostat) significantly induced NIS, both as mRNA and as protein, through the increase of NIS promoter activity, with the final consequence of obtaining a significant up-take of iodide in MCF7, T47D, and MDA-MB231 breast cancer cells. Moreover, we observed that LBH589 causes a significant reduction in cell viability of estrogen-sensitive and -insensitive breast cancer cells within nanomolar range. The anti-tumor effect of LBH589 is sustained by apoptosis induction and cell cycle arrest in G₂/M. In conclusion, our data suggest that LBH589 might be a powerful tool in the management of breast cancer due to its multiple effects and support a potential application of LBH589 in the diagnosis and treatment of this disease.     

Clinical significance of CYLD downregulation in breast cancer

Cylindromatosis (CYLD) is a tumor suppressor gene that is mutated in familial cylindromatosis, a rare autosomal dominant disorder associated with numerous benign skin adnexal tumors. CYLD is now known to regulate various signaling pathways, including transforming growth factor-β signaling, Wnt/β-catenin signaling, and NF-κB signaling by deubiquitinating upstream regulatory factors. Downregulation of CYLD has been reported in several malignancies; however, the clinical significance of CYLD expression in many malignancies, including breast cancer, remains to be elucidated. This study investigated the clinical significance of CYLD in breast cancer and its roles in tumor progression. We evaluated CYLD expression in matched normal breast tissue samples and tumor breast tissue samples from 26 patients with breast cancer and in a series of breast cancer cell lines. In addition, by means of immunohistochemistry, we investigated CYLD protein expression and its clinical significance in 244 breast cancer cases. We also analyzed the effects of CYLD repression or overexpression on breast cancer cell viability, cell migration, and NF-κB activity with or without receptor activator of NF-κB ligand (RANKL) stimulation. Breast cancer tissues demonstrated significantly reduced CYLD mRNA expression compared with normal breast tissues. Downregulation of CYLD promoted cell survival and migratory activities through NF-κB activation, whereas CYLD overexpression inhibited those activities in MDA-MB-231 cells. As an important finding, CYLD overexpression also inhibited RANKL-induced NF-κB activation. Our immunohistochemical analysis revealed that reduced CYLD protein expression was significantly correlated with estrogen receptor negativity, high Ki-67 index, high nuclear grade, decreased disease-free survival, and reduced breast cancer-specific survival in primary breast cancer. Moreover, reduced CYLD expression was an independent factor for poor prognosis in breast cancer. CYLD downregulation may promote breast cancer metastasis via NF-κB activation, including RANKL signaling.     

Involvement of NF-κB-mediated expression of galectin-3-binding protein in TNF-α-induced breast cancer cell adhesion

Galectin-3-binding protein (G3BP) is highly expressed in various types of cancer and is thought to be involved in cancer malignancy; however, the role of G3BP in breast cancer cells is not fully understood. In this study, we investigated the role of NF-κB in the adhesion of breast cancer cells to a substrate by using (-)-DHMEQ, a specific inhibitor of NF-κB. (-)-DHMEQ inhibited both TNF-α-induced G3BP expression and cell adhesion in human breast cancer cell lines. We also found that knockdown of G3BP suppressed the adhesion, while its overexpression increased the adhesion. These data reveal that (-)-DHMEQ suppresses breast cancer cell adhesion by inhibiting NF-κB-regulated G3BP expression.     

MicroRNA-125b upregulation confers aromatase inhibitor resistance and is a novel marker of poor prognosis in breast cancer

Introduction

Increasing evidence indicates that microRNAs (miRNAs) are important players in oncogenesis. Considering the widespread use of aromatase inhibitors (AIs) in endocrine therapy as a first-line treatment for postmenopausal estrogen receptor α–positive breast cancer patients, identifying deregulated expression levels of miRNAs in association with AI resistance is of utmost importance.

Methods

To gain further insight into the molecular mechanisms underlying the AI resistance, we performed miRNA microarray experiments using a new model of acquired resistance to letrozole (Res-Let cells), obtained by long-term exposure of aromatase-overexpressing MCF-7 cells (MCF-7aro cells) to letrozole, and a model of acquired anastrozole resistance (Res-Ana cells). Three miRNAs (miR-125b, miR-205 and miR-424) similarly deregulated in both AI-resistant cell lines were then investigated in terms of their functional role in AI resistance development and breast cancer cell aggressiveness and their clinical relevance using a cohort of 65 primary breast tumor samples.

Results

We identified the deregulated expression of 33 miRNAs in Res-Let cells and of 18 miRNAs in Res-Ana cells compared with the sensitive MCF-7aro cell line. The top-ranked Kyoto Encyclopedia of Genes and Genomes pathways delineated by both miRNA signatures converged on the AKT/mTOR pathway, which was found to be constitutively activated in both AI-resistant cell lines. We report for the first time, to our knowledge, that ectopic overexpression of either miR-125b or miR-205, or the silencing of miR-424 expression, in the sensitive MCF-7aro cell line was sufficient to confer resistance to letrozole and anastrozole, to target and activate the AKT/mTOR pathway and to increase the formation capacity of stem-like and tumor-initiating cells possessing self-renewing properties. Increasing miR-125b expression levels was also sufficient to confer estrogen-independent growth properties to the sensitive MCF-7aro cell line. We also found that elevated miR-125b expression levels were a novel marker for poor prognosis in breast cancer and that targeting miR-125b in Res-Let cells overcame letrozole resistance.

Conclusion

This study highlights that acquisition of specific deregulated miRNAs is a newly discovered alternative mechanism developed by AI-resistant breast cancer cells to achieve constitutive activation of the AKT/mTOR pathway and to develop AI resistance. It also highlights that miR-125b is a new biomarker of poor prognosis and a candidate therapeutic target in AI-resistant breast cancers.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-015-0515-1) contains supplementary material, which is available to authorized users.     

姜黄素对乳腺癌MDA-MB-231细胞NOTCH1 和NF-κB表达的影响

 目的 检测姜黄素作用于乳腺癌细胞后NOTCH1和核转录因子-κB（NF-κB）的变化,了解姜黄素抑制乳腺癌细胞增殖的可能机制。 方法 不同剂量（1.25,5.0,20.0μmol/L）姜黄素分别处理乳腺癌MDA-MB-231细胞24,48,72h,MTT法检测细胞增殖 改变。RT-PCR和Western blot检测NOTCH1、NF-κB mRNA和蛋白质表达。 结果 MTT显示,20μmol/L姜黄素处理72h,乳腺癌细胞抑制率为（52.0±0.42）%,与余组比较差异具有统计学意义;PCR结果显示随着剂量和时间的增加,NOTCH1和NF-κB的OD值逐渐下降, Western blot的结果与PCR一致。 结论 姜黄素可下调乳腺癌细胞NOTCH1及NF-κB表达,并呈现剂量和时间依赖性,提示姜黄素具有抑制乳腺癌细胞增殖的作用。     

Overcoming aromatase inhibitor resistance in breast cancer: possible mechanisms and clinical applications

Estrogen plays crucial roles in the progression of hormone-dependent breast cancers through activation of nuclear estrogen receptor α (ER). Estrogen is produced locally from circulating inactive steroids and adrenal androgens in postmenopausal women. However, conversion by aromatase is a rate-limiting step in intratumoral estrogen production in breast cancer. Aromatase inhibitors (AIs) inhibit the growth of hormone-dependent breast cancers by blocking the conversion of adrenal androgens to estrogen and by unmasking the inhibitory effect of androgens, acting via the androgen receptor (AR). AIs are thus a standard treatment option for postmenopausal hormone-dependent breast cancer. However, although initial use of AIs provides substantial clinical benefit, some breast cancer patients relapse because of the acquisition of AI resistance. A better understanding of the mechanisms of AI resistance may contribute to the development of new therapeutic strategies and aid in the search for new therapeutic targets and agents. We have investigated AI-resistance mechanisms and established six AI-resistant cell lines. Some of them exhibit estrogen depletion-resistance properties via constitutive ER-activation or ER-independent growth signaling. We examined how breast cancer cells can adapt to estrogen depletion and androgen superabundance. Estrogen and estrogenic androgen produced independently from aromatase contributed to cell proliferation in some of these cell lines, while another showed AR-dependent cell proliferation. Based on these findings, currently proposed AI-resistance mechanisms include an aromatase-independent estrogen-producing pathway, estrogen-independent ER function, and ER-independent growth signaling. This review summarizes several hypotheses of AI-resistance mechanisms and discusses how existing or novel therapeutic agents may be applied to treat AI-resistant breast cancers.     

Annexin-1 interacts with NEMO and RIP1 to constitutively activate IKK complex and NF-κB: implication in breast cancer metastasis

The molecular mechanisms underlying constitutive nuclear factor-κB (NF-κB) activation in solid tumors has not been elucidated. We show that Annexin-1 (ANXA1) is involved in this process, and suppression of ANXA1 in highly metastatic breast cancer cells impedes migration and metastasis capabilities in vitro and in vivo. ANXA1 expression correlates with NF-κB activity, suggesting that ANXA1 may be required for the constitutive activity of IκB kinase (IKK) and NF-κB in highly metatstatic breast cancer. Gel-filtration analysis demonstrated that ANXA1 co-elutes with the members of the IKK complex and NF-κB signaling pathway, and immunoprecipitation confirmed that ANXA1 can bind to and interact with IKKγ or NEMO, but not IKKα or IKKβ. Importantly, silencing of ANXA1 prevents the interaction of NEMO and RIP1, which indicates that ANXA1 is required for the recruitment of RIP1 to the IKK complex, which may be important for the activation of NF-κB. Downstream targets of NF-κB include uPA and CXCR4, which can be modulated by ANXA1 silencing. CXCR4-mediated migration of breast cancer cell lines in response to CXCL12 was significantly modulated by ANXA1, indicating its importance in the tissue-specific migration of breast cancer cells. Chromatin immunoprecipitation experiments confirmed that in ANXA1 overexpressed cells, NF-κB was recruited to CXCR4 promoter without external stimulation, indicating that ANXA1 is critical for the constitutive activation of NF-κB in breast cancer to promote metastasis. Finally, we show that ANXA1 overexpression enhances metastasis and reduces survival in an intracardiac metastasis model, while ANXA1-deficient mice crossed with MMTV-PyMT mice display significantly less metastasis than their heterozygous littermates, indicating that ANXA1 is an important gene in breast cancer metastasis. Our data reveal that ANXA1 can constitutively activate NF-κB in breast cancer cells through the interaction with the IKK complex, and suggests that modulating ANXA1 levels has therapeutic potential to suppress breast cancer metastasis.     

Abrogation of MAPK and Akt signaling by AEE788 synergistically potentiates histone deacetylase inhibitor-induced apoptosis through reactive oxygen species generation.

PURPOSE: To evaluate the effects of combining the multiple receptor tyrosine kinase inhibitor AEE788 and histone deacetylase (HDAC) inhibitors on cytotoxicity in a broad spectrum of cancer cell lines, including cisplatin-resistant ovarian adenocarcinoma cells. EXPERIMENTAL DESIGN: Multiple cancer cell lines were treated in vitro using AEE788 and HDAC inhibitors (LBH589, LAQ824, and trichostatin A), either alone or in combination. Effects on cytotoxicity were determined by growth and morphologic assays. Effects of the combination on cell signaling pathways were determined by Western blotting, and the results were confirmed using pathway-specific inhibitors and transfection of constitutively active proteins. RESULTS: Cell treatment with AEE788 and HDAC inhibitors (LBH589, LAQ824, and trichostatin A) in combination resulted in synergistic induction of apoptosis in non-small cell lung cancer (MV522, A549), ovarian cancer (SKOV-3), and leukemia (K562, Jurkat, and ML-1) cells and in OV202hp cisplatin-resistant human ovarian cancer cells. AEE788 alone or in combination with LBH589 inactivated mitogen-activated protein kinase (MAPK) and Akt cascades. Inhibition of either MAPK and/or Akt enhanced LBH589-induced apoptosis. In contrast, constitutively active MAPK or Akt attenuated LBH589 or LBH589 + AEE788-induced apoptosis. Increased apoptosis was correlated with enhanced reactive oxygen species (ROS) generation. The free radical scavenger N-acetyl-l-cysteine not only substantially suppressed the ROS accumulation but also blocked the induction of apoptosis mediated by cotreatment with AEE788 and LBH589. CONCLUSION: Collectively, these results show that MAPK and Akt inactivation along with ROS generation contribute to the synergistic cytotoxicity of the combination of AEE788 and HDAC inhibitors in a variety of human cancer cell types. This combination regimen warrants further preclinical and possible clinical study for a broad spectrum of cancers.     

Targeting interferon response genes sensitizes aromatase inhibitor resistant breast cancer cells to estrogen-induced cell death

Introduction

Estrogen deprivation using aromatase inhibitors (AIs) is currently the standard of care for postmenopausal women with hormone receptor-positive breast cancer. Unfortunately, the majority of patients treated with AIs eventually develop resistance, inevitably resulting in patient relapse and, ultimately, death. The mechanism by which resistance occurs is still not completely known, however, recent studies suggest that impaired/defective interferon signaling might play a role. In the present study, we assessed the functional role of IFITM1 and PLSCR1; two well-known interferon response genes in AI resistance.

Methods

Real-time PCR and Western blot analyses were used to assess mRNA and protein levels of IFITM1, PLSCR1, STAT1, STAT2, and IRF-7 in AI-resistant MCF-7:5C breast cancer cells and AI-sensitive MCF-7 and T47D cells. Immunohistochemistry (IHC) staining was performed on tissue microarrays consisting of normal breast tissues, primary breast tumors, and AI-resistant recurrence tumors. Enzyme-linked immunosorbent assay was used to quantitate intracellular IFNα level. Neutralizing antibody was used to block type 1 interferon receptor IFNAR1 signaling. Small interference RNA (siRNA) was used to knockdown IFITM1, PLSCR1, STAT1, STAT2, IRF-7, and IFNα expression.

Results

We found that IFITM1 and PLSCR1 were constitutively overexpressed in AI-resistant MCF-7:5C breast cancer cells and AI-resistant tumors and that siRNA knockdown of IFITM1 significantly inhibited the ability of the resistant cells to proliferate, migrate, and invade. Interestingly, suppression of IFITM1 significantly enhanced estradiol-induced cell death in AI-resistant MCF-7:5C cells and markedly increased expression of p21, Bax, and Noxa in these cells. Significantly elevated level of IFNα was detected in AI-resistant MCF-7:5C cells compared to parental MCF-7 cells and suppression of IFNα dramatically reduced IFITM1, PLSCR1, p-STAT1, and p-STAT2 expression in the resistant cells. Lastly, neutralizing antibody against IFNAR1/2 and knockdown of STAT1/STAT2 completely suppressed IFITM1, PLSCR1, p-STAT1, and p-STAT2 expression in the resistant cells, thus confirming the involvement of the canonical IFNα signaling pathway in driving the overexpression of IFITM1 and other interferon-stimulated genes (ISGs) in the resistant cells.

Conclusion

Overall, these results demonstrate that constitutive overexpression of ISGs enhances the progression of AI-resistant breast cancer and that suppression of IFITM1 and other ISGs sensitizes AI-resistant cells to estrogen-induced cell death.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-014-0506-7) contains supplementary material, which is available to authorized users.     

Stephania delavayi Diels. inhibits breast carcinoma proliferation through the p38 MAPK/NF-κB/COX-2 pathway

The nuclear factor κB (NF-κB)/inhibitor of κ kinase-β (IKKβ) signaling pathway is important in tumor promotion and progression. MDA-MB-231 human breast carcinoma cells express COX-2 and show a constitutive phosphorylation of NF-κB. Many non-specific inhibitors of IKKβ and NF-κB are used to inhibit tumor promotion and progression. The Stephania delavayi Diels. (S. delavayi Diels.) extract has been reported to safely activate B cell immunity and there is evidence suggesting that it may be a promising new anticancer therapeutic agent. S. delavayi Diels. extract suppressed proliferation of the breast cancer cell lines MDA-MB-231 and MCF-7 by inducing cell death. To aid in the development of the S. delavayi Diels. extract as a therapeutic agent, its mechanisms of action were investigated, in particular its effects on p38 MAPK, NF-κB and COX-2, which play important roles in inflammation and cancer. S. delavayi Diels. stimulated p38 MAPK phosphorylation but reduced NF-κB phosphorylation and COX-2 expression in a dose- and time-dependent manner. Thus, S. delavayi Diels., which appears to act primarily through p38 MAPK/NF-κB/COX-2 signaling in breast carcinomas, may be a potent anticancer agent with target specificity and low toxicity.     

MicroRNA-520/373 family functions as a tumor suppressor in estrogen receptor negative breast cancer by targeting NF-κB and TGF-β signaling pathways

MicroRNAs (miRNAs) as modulators of gene expression have been described to display both tumor-promoting and tumor-suppressive functions. Although their role has been studied in different tumor types, little is known about how they regulate nuclear factor κB (NF-κB) signaling in breast cancer. Here, we performed an unbiased whole genome miRNA (miRome) screen to identify novel modulators of NF-κB pathway in breast cancer. The screen identified 13 miRNA families whose members induced consistent effects on NF-κB activity. Among those, the miR-520/373 family inhibited NF-κB signaling through direct targeting of RELA and thus strongly reduced expression and secretion of the pro-inflammatory cytokines interleukin (IL)-6 and IL-8. With a combination of in vitro and in vivo approaches, we propose a metastasis-suppressive role of miR-520/373 family. miR-520c and miR-373 abrogated both in vitro cell invasion and in vivo intravasation of highly invasive MDA-MB-231 cells. However, knockdown of RELA did not affect their metastatic ability. mRNA profiling of MDA-MB-231 cells on overexpression of miR-520/373 members revealed a strong downregulation of transforming growth factor-β (TGF-β) signaling. Mechanistically, the metastasis-suppressive role of miR-520/373 can be attributed to direct suppression of TGFBR2, as the silencing of TGFBR2 phenocopied the effects of miR-520/373 overexpression on suppression of Smad-dependent expression of the metastasis-promoting genes parathyroid hormone-related protein, plasminogen activator inhibitor-1 and angiopoietin-like 4 as well as tumor cell invasion, in vitro and in vivo. A negative correlation between miR-520c and TGFBR2 expression was observed in estrogen receptor negative (ER(-)) breast cancer patients but not in the ER positive (ER(+)) subtype. Remarkably, decreased expression of miR-520c correlated with lymph node metastasis specifically in ER(-) tumors. Taken together, our findings reveal that miR-520/373 family has a tumor-suppressive role in ER(-) breast cancer by acting as a link between the NF-κB and TGF-β pathways and may thus contribute to the interplay of tumor progression, metastasis and inflammation.     

乳腺癌患者核基质结合区结合蛋白1和核因子相关蛋白κB的表达水平及其相关性分析

目的 研究特异性核基质结合区结合蛋白1(SATB1)和核转录因子kappaB p65(NF-κB p65)蛋白的表达,探讨其表达与乳腺癌发生、发展的相关性.方法 应用免疫组织化学染色法检测80例乳腺癌组织样本中的蛋白SATB1和NF-κB p65的表达,分析其相互关系,并探讨其与乳腺癌临床特征之间的关系.结果 80例乳腺癌组织样本中SATB1和NF-κB p65的阳性表达率分别为70.00%和56.25%.SATB1和NF-κB p65的表达与肿瘤大小、组织学分级、ER受体状态和淋巴结转移有关,与年龄和TNM分期无关.SATB1和NF-κB p65在乳腺组织中的表达呈明显正相关.结论 SATB1和NF-κB p65在乳腺癌组织中协同高表达,与乳腺癌患者的临床特征存在密切联系.     

The importance of HER2 signaling in the tumor-initiating cell population in aromatase inhibitor-resistant breast cancer

Aromatase inhibitors (AIs) are an effective therapy in treating estrogen receptor-positive breast cancer. Nonetheless, a significant percentage of patients either do not respond or become resistant to AIs. Decreased dependence on ER-signaling and increased dependence on growth factor receptor signaling pathways, particularly human epidermal growth factor receptor 2 (EGFR2/HER2), have been implicated in AI resistance. However, the role of growth factor signaling remains unclear. This current study investigates the possibility that signaling either through HER2 alone or through interplay between epidermal growth factor receptor 1 (EGFR/HER1) and HER2 mediates AI resistance by increasing the tumor initiating cell (TIC) subpopulation in AI-resistant cells via regulation of stem cell markers, such as breast cancer resistance protein (BCRP). TICs and BCRP are both known to be involved in drug resistance. Results from in vitro analyses of AI-resistant versus AI-sensitive cells and HER2-versus HER2+ cells, as well as from in vivo xenograft tumors, indicate that (1) AI-resistant cells overexpress both HER2 and BCRP and exhibit increased TIC characteristics compared to AI-sensitive cells; (2) inhibition of HER2 and/or BCRP decrease TIC characteristics in letrozole-resistant cells; and (3) HER2 and its dimerization partner EGFR/HER1 are involved in the regulation of BCRP. Overall, these results suggest that reducing or eliminating the TIC subpopulation with agents that target BCRP, HER2, EGFR/HER1, and/or their downstream kinase pathways could be effective in preventing and/or treating acquired AI resistance.     

Vascular endothelial growth factor regulates myeloid cell leukemia-1 expression through neuropilin-1-dependent activation of c-MET signaling in human prostate cancer cells

Background

Nuclear factor-κB (NF-κB) is constitutively activated in many cancers and plays a key role in promoting cell proliferation, survival, and invasion. Our understanding of NF-κB signaling in thyroid cancer, however, is limited. In this study, we have investigated the role of NF-κB signaling in thyroid cancer cell proliferation, invasion, and apoptosis using selective genetic inhibition of NF-κB in advanced thyroid cancer cell lines.

Results

Three pharmacologic inhibitors of NF-κB differentially inhibited growth in a panel of advanced thyroid cancer cell lines, suggesting that these NF-κB inhibitors may have off-target effects. We therefore used a selective genetic approach to inhibit NF-κB signaling by overexpression of a dominant-negative IκBα (mIκBα). These studies revealed decreased cell growth in only one of five thyroid cancer cell lines (8505C), which occurred through a block in the S-G2/M transition. Resistance to TNFα-induced apoptosis was observed in all cell lines, likely through an NF-κB-dependent mechanism. Inhibition of NF-κB by mIκBα sensitized a subset of cell lines to TNFα-induced apoptosis. Sensitive cell lines displayed sustained activation of the stress-activated protein kinase/c-Jun NH2-terminal kinase (SAPK/JNK) pathway, defining a potential mechanism of response. Finally, NF-κB inhibition by mIκBα expression differentially reduced thyroid cancer cell invasion in these thyroid cancer cell lines. Sensitive cell lines demonstrated approximately a two-fold decrease in invasion, which was associated with differential expression of MMP-13. MMP-9 was reduced by mIκBα expression in all cell lines tested.

Conclusions

These data indicate that selective inhibition of NF-κB represents an attractive therapeutic target for the treatment of advanced thyroid. However, it is apparent that global regulation of thyroid cancer cell growth and invasion is not achieved by NF-κB signaling alone. Instead, our findings suggest that other important molecular processes play a critical role in defining the extent of NF-κB function within cancer cells.     

NF-κB/SCCI/ATG5引起细胞自噬及降低顺铂敏感性的机制研究

目的:探究NF-κB/SCCI/ATG5引起细胞自噬及降低顺铂敏感性的机制。方法:选取2016年1月至2018年1月我院收治的非小细胞肺癌患者50例,检测SCCI在非小细胞肺癌组织和细胞系中的表达,入核后SCCI和NF-κB的共定位情况,NF-κB激活SCCI的机制及SCCI调控ATG5引起自噬的机制。结果:SCCI在癌组织中的表达显著高于癌旁组织（P＜0.05）。SCCI、SCCI mRNA在肺腺癌细胞系A549、H1299、SPC-A-1中的表达均高于在正常支气管上皮16HB中的表达（P＜0.05）。非小细胞肺癌细胞系A549中SCCI在细胞胞浆、胞核中的表达均较高（P＞0.05）。SCCI在肺癌细胞组织细胞浆、细胞核中均有所表达。加入顺铂后肺癌细胞系A549细胞胞浆、胞核蛋白中NF-κB、SCCI总蛋白同时增加,胞核中SCCI表达明显增加,均高于加入顺铂前（P＜0.05）。SCCI和NF-κB的具体结合部位在细胞核中。加入顺铂后核内SCCI蛋白表达增加,自噬相关markers、ATG5和LC3II/LC3I表达增加,均高于加入顺铂前（P＜0.05）。SCCI基因沉默前,顺铂耐药性较低,SCCI基因沉默后,顺铂耐药性升高。SCCI和ATG5的共同结合部位在细胞核中。结论:通过激活NF-κB/SCCI/ATG5信号通路,可激活细胞自噬,作用于自噬相关markers、ATG5和LC3II/LC3I基因,降低非小细胞肺癌细胞顺铂耐药性,为临床上非小细胞肺癌的诊治及预后提供了依据。