Association of tissue inhibitor of metalloproteinases-1 and Ki67 in estrogen receptor positive breast cancer

Endosomal protein expression of γ1-adaptin is associated with tumor growth activity and relapse-free survival in breast cancer

BACKGROUND

γ1-Adaptin is a subunit of adaptor protein complex-1 (AP-1), which regulates intracellular transport between the trans-Golgi network (TGN) and endosomes. Since expression levels of AP-1 subunits have been reported to be associated with cell proliferation and cancer malignancy, we investigated the relationships between the immunohistochemical expression of γ1-adaptin and both clinicopathological factors and relapse-free survival (RFS) in breast cancer tissue.

MATERIALS AND METHODS

SK-BR-3 cell line depleted of γ1-adaptin was used for cell proliferation, migration, and invasion assay. Intracellular localization of γ1-adaptin was examined with immunohistochemistry (IHC) using an antibody against γ1-adaptin, and with double immunohistofluorescence (IHF) microscopy using markers for the TGN and endosome. γ1-Adaptin intensities in IHC samples from 199 primary breast cancer patients were quantified and assessed in relation to clinicopathological factors and RFS.

RESULTS

Cell growth, migration, and invasion of SK-BR-3 cells were significantly suppressed by the depletion of γ1-adaptin. Although the staining patterns in the cancer tissues varied among cases by IHC, double IHF demonstrated that γ1-adaptin was mainly localized in EEA1-positive endosomes, but not in the TGN. γ1-Adaptin intensity was significantly higher in the tumor regions than in non-tumor regions. It was also higher in patients with Ki-67 (high), ER (-), PgR (-), and HER2 (+). Among subtypes of breast cancer, γ1-adaptin intensity was higher in HER2 than in luminal A or luminal B. The results of the survival analysis indicated that high γ1-adaptin intensity was significantly associated with worse RFS, and this association was also observed in group with ER (+), PgR (+), HER2 (-), Ki-67 (high), or luminal B. In addition, the Cox proportional hazards model showed that high γ1-adaptin intensity was an independent prognostic factor.

CONCLUSION

These results suggest that the endosomal expression of γ1-adaptin is positively correlated with breast cancer malignancy and could be a novel prognostic marker.

Evaluating human epidermal growth factor receptor 2 roles in the efficacy of Tamoxifen treatment in breast cancer, a systematic review

PURPOSE

Hormone therapy with Tamoxifen is an effective treatment that can decrease recurrence rate and mortality. Numerous molecular mechanisms can modify the response to Tamoxifen. The objective of this study was to determine Tamoxifen efficacy on patients' recurrence and mortality rates, according to the human epidermal growth factor receptor 2 (HER2) status.

METHODS

In this meta-analysis of published studies, relapse and death rates were measured in both HER2 negative and positive patients treated with Tamoxifen. Besides, the relative risk of treatment with Tamoxifen compared to no Tamoxifen treatment was evaluated in both HER2 positive and negative patients.

RESULTS

There was an increased risk of recurrence in HER2 positive patients who received Tamoxifen compared with HER2 negative ones (RR = 1.63, p value < 0.001). Tamoxifen treatment is associated with decreased relapse rate (RR = 0.70, p value < 0.001); however, it did not effect on HER2 positive ones (RR = 1, p value = 0.99).

CONCLUSION

According to the analysis result, the relapse rate in breast cancer patients who were treated with Tamoxifen depends on the HER2 situation. Despite the limited sample size, it is revealed that Tamoxifen can decrease the relapse rate only in HER2 negative patients.

MCM3 upregulation confers endocrine resistance in breast cancer and is a predictive marker of diminished tamoxifen benefit

Resistance to endocrine therapy in estrogen receptor-positive (ER+) breast cancer is a major clinical problem with poorly understood mechanisms. There is an unmet need for prognostic and predictive biomarkers to allow appropriate therapeutic targeting. We evaluated the mechanism by which minichromosome maintenance protein 3 (MCM3) influences endocrine resistance and its predictive/prognostic potential in ER+ breast cancer. We discovered that ER+ breast cancer cells survive tamoxifen and letrozole treatments through upregulation of minichromosome maintenance proteins (MCMs), including MCM3, which are key molecules in the cell cycle and DNA replication. Lowering MCM3 expression in endocrine-resistant cells restored drug sensitivity and altered phosphorylation of cell cycle regulators, including p53(Ser315,33), CHK1(Ser317), and cdc25b(Ser323), suggesting that the interaction of MCM3 with cell cycle proteins is an important mechanism of overcoming replicative stress and anti-proliferative effects of endocrine treatments. Interestingly, the MCM3 levels did not affect the efficacy of growth inhibitory by CDK4/6 inhibitors. Evaluation of MCM3 levels in primary tumors from four independent cohorts of breast cancer patients receiving adjuvant tamoxifen mono-therapy or no adjuvant treatment, including the Stockholm tamoxifen (STO-3) trial, showed MCM3 to be an independent prognostic marker adding information beyond Ki67. In addition, MCM3 was shown to be a predictive marker of response to endocrine treatment. Our study reveals a coordinated signaling network centered around MCM3 that limits response to endocrine therapy in ER+ breast cancer and identifies MCM3 as a clinically useful prognostic and predictive biomarker that allows personalized treatment of ER+ breast cancer patients.

Utility of synthetic MRI in predicting the Ki-67 status of oestrogen receptor-positive breast cancer: a feasibility study

AIM

To evaluate the utility of synthetic magnetic resonance imaging (MRI) of the breast in predicting the Ki-67 status in patients with oestrogen receptor (ER)-positive breast cancer.

MATERIALS AND METHODS

Forty-nine patients with 50 histopathologically proven breast cancers who underwent additional synthetic MRI were enrolled in the present study. Using synthetic MRI images, T1 and T2 relaxation times and their standard deviations (SD) in the breast lesions before (T1-Pre, T2-Pre, PD-Pre, SD of T1-Pre, SD of T2-Pre, SD of PD-Pre) and after (T1-Gd, T2-Gd, PD-Gd, SD of T1-Gd, SD of T2-Gd, SD of PD-Gd) contrast agent injection were obtained. These quantitative values were compared between the low Ki-67 expression (<14%) lesions (low-proliferation group: n=23) and high Ki-67 expression (≥14%) lesions (high-proliferation group: n=27).

RESULTS

The univariate analysis showed that the SD of T1-Gd (p<0.001) and T2-Gd (p=0.042) were significantly higher in the high-proliferation group than in the low-proliferation group. Multivariate analysis further showed that the SD of T1-Gd was a significant and independent predictor of Ki-67 expression, with an area under the receiver operating characteristic (AUROC) curve of 0.885. The sensitivity, specificity, and accuracy of the SD of T1-Gd with an optimal cut-off value of 98.5 were 77.8%, 87%, and 82%, respectively.

CONCLUSION

The SD of T1-Gd obtained from synthetic MRI was useful to predict Ki-67 status.

Changes in the Ki-67 labeling index between primary breast cancer and metachronous metastatic axillary lymph node: A retrospective observational study

BACKGROUND

The Ki-67 labeling index (LI) is a well-known prognostic factor for primary breast cancer, but its clinical significance for metachronous axillary lymph node (ALN) recurrence has not been well documented.

METHODS

Ki-67 expression in primary tumors (PTs) and ALN metastases (ALNMs) was evaluated in 21 patients and quantified to investigate the relationship between Ki-67 LIs in PTs and metachronous ALNMs.

RESULTS

The median Ki-67 LIs in the PTs and ALNMs were 25.2% (range: 2.3-80.2%) and 70% (range: 10.4-97.4%), respectively. A majority of patients had higher Ki-67 LIs in ALNMs than in PTs (76.2%, 16/21). Disease-specific survival was significantly better in patients with a lower-than-median ALNM Ki-67 LI (P = 0.019, log-rank test). Receiver operating characteristic curves showed a PT Ki-67 LI of 62.8% as the optimal cutoff value and an ALNM Ki-67 LI of 65.1%. Accordingly, we divided the patients into four groups: PT Ki-67 LI lower than 62.8%/ALNM Ki-67 LI lower than 65.1%, PT Ki-67 LI lower/ALNM Ki-67 LI higher, PT Ki-67 LI higher/ALNM Ki-67 LI higher, and PT Ki-67 LI higher/ALNM Ki-67 LI lower. Disease-specific survival was significantly better in patients with Ki-67 LI lower/ALNM Ki-67 LI lower than in the other groups.

CONCLUSION

This is the first study to show that the Ki-67 LI in metachronous ALNM is a prognostic factor for patients with metachronous ALN recurrence of breast cancer.

Persistent homology index as a robust quantitative measure of immunohistochemical scoring

Immunohistochemical data (IHC) plays an important role in clinical practice, and is typically gathered in a semi-quantitative fashion that relies on some degree of visual scoring. However, visual scoring by a pathologist is inherently subjective and manifests both intra-observer and inter-observer variability. In this study, we introduce a novel computer-aided quantification methodology for immunohistochemical scoring that uses the algebraic concept of persistent homology. Using 8 bit grayscale image data derived from 90 specimens of invasive ductal carcinoma of the breast, stained for the replicative marker Ki-67, we computed homology classes. These were then compared to nuclear grades and the Ki-67 labeling indices obtained by visual scoring. Three metrics for IHC staining were newly defined: Persistent Homology Index (PHI), center coordinates of positive and negative groups, and the sum of squares within groups (WSS). This study demonstrates that PHI, a novel index for immunohistochemical labeling using persistent homology, can produce highly similar data to that generated by a pathologist using visual evaluation. The potential benefits associated with our novel technology include both improved quantification and reproducibility. Since our method reflects cellularity and nuclear atypia, it carries a greater quantity of biologic data compared to conventional evaluation using Ki-67.

ATP citrate lyase is increased in human breast cancer, depletion of which promotes apoptosis

Breast cancer is a malignant tumor that is harmful to women’s health around the world. Investigating the biological mechanism is, therefore, of pivotal importance to improve patients’ prognoses. Compared to non-neoplastic tissues, enhanced glucose and lipid metabolism is one of the most common properties of malignant breast cancer. Adenosine triphosphate (ATP) citrate lyase is a key enzyme linking aerobic glycolysis and fatty acid synthesis and is of high biological and prognostic significance in breast cancer. In our clinical study, fresh clinical tissues were used to analyze ATP citrate lyase expression by western blotting, and paraffin archived samples from 62 breast cancer patients were used to analyze ATP citrate lyase expression by immunohistochemistry. In the cellular study, following small interfering RNA–mediated inhibition of ATP citrate lyase in MCF-7 cells, cell viability and apoptosis were measured using the Cell Counting Kit-8 and flow cytometry, respectively. Breast cancer tissues showed strong expression of ATP citrate lyase, whereas adjacent normal tissues showed weak expression. Silencing of endogenous ATP citrate lyase expression by small interfering RNA in MCF-7 cells suppressed cell viability and increased cell apoptosis. Collectively, our study revealed that expression of ATP citrate lyase was significantly increased in breast cancer tissue compared with normal tissue. In addition, we found that depletion of ATP citrate lyase suppressed tumor growth, which suggests that ATP citrate lyase–related inhibitors might be potential therapeutic approaches for breast cancer.

Relation between Ki-67, ER, PR, Her2/neu, p21, EGFR, and TOP II-α expression in invasive ductal breast cancer patients and correlations with prognosis

The aim of the present study was to investigate the expression of the transcription factor Ki-67, ER, PR, Her2/neu, p21, EGFR, and TOP II-α in the tumor tissue of patients with invasive ductal carcinoma(IDC); in addition, we examined correlations between these markers. Two hundred and sixteen IDC patients, who were not previously been treated with chemo- or radiotherapy, were included in the study. All tumors were grade I-III. Expression of molecular markers was determined by immunohistochemical analysis on paraffin-embedded tissue sections. Follow-up data were collected for 3 months to 10 years and analyzed for tumor recurrence, survival time, and prognostic risk factors. We determined Ki-67 expression correlates with the expression of ER, PR, HER-2, EGFR, and TOP-α, as well as lymph node involvement, high tumor grade, lymphovascular invasion, high tumor stage, and high TNM stage in IDC. Positive Ki-67 expression was a risk factor for rapid tumor recurrence and may help tumor progression, leading to poor prognosis in IDC. Ki-67 was directly correlated with EGFR, TOP II-α, lymph node involvement, high tumor grade, lymphovascular invasion, high tumor stage, and high TNM stage in the hormone receptor subtypes of breast cancer. In triple negative breast cancer, Ki-67 correlated with TOP II-α. Expression of Ki-67 correlated with that of ER, PR, HER-2, EGFR, TOP II-α, and p21. In addition, the biomarker Ki-67 has a role as a prognostic factor and indicates a poor prognosis in IDC.

TIMP-1 and CEA as biomarkers in third-line treatment with irinotecan and cetuximab for metastatic colorectal cancer

KRAS wild-type (wt) status determines indication for treatment with combination therapy, including epidermal growth factor receptor (EGFR) inhibitors, but still, the overall response rate in KRAS wt patients is less than 40 %. Consequently, the majority of patients will suffer from substantial side effects and no apparent benefit. Tissue inhibitor of metalloproteinases-1 is a glycoprotein, which regulates metalloproteinases and may consequently imply a central role in tumour progression. Furthermore, it is closely related to the EGFR regulation and has shown promising potential as a biomarker in colorectal cancer (CRC). The aim of the present study was to investigate the clinical value of TIMP-1 in patients with metastatic colorectal cancer (mCRC) treated with cetuximab and irinotecan. Patients with chemotherapy-resistant mCRC referred to third-line treatment with cetuximab (initial 400 mg/m(2) followed by weekly 250 mg/m(2))/irinotecan (350 mg/m(2) q3w) were prospectively included in the biomarker study, as previously published. Pre-treatment blood samples were collected, and plasma TIMP-1 was measured by a validated in-house ELISA assay. In addition, carcinoembryonic antigen (CEA) measurement was performed with a standardised method. A total of 107 patients were included in the biomarker study. The median baseline plasma TIMP-1 level was 271.1 ng/ml (range 65.9-1432 ng/ml) with no significant associations with baseline clinical characteristics. Median baseline plasma TIMP-1 levels were significantly higher in patients with early progression compared to patients who achieved disease control, 349 ng/ml (233-398 95 % confidence interval (CI)) and 215 ng/ml (155-289 95 % CI), respectively, p = 0.03, suggesting some association with treatment efficacy. When dividing patients according to TIMP-1 tertiles, the median progression-free survival (PFS) in patients with a high level of TIMP-1 was 2.4 months (95 % CI 2.1-4.1) compared to 3.3 months (95 % CI 2.1-6.2) and 4.7 months (95 % 3.2-7.6) in patients with intermediate or low levels, respectively. Analysis of TIMP-1 as a continuous variable revealed a shorter PFS associated with increasing levels of TIMP-1 (hazard ratio (HR) 1.36). These results translated into a significantly lower overall survival (OS) in patients with a high baseline TIMP-1 level (4.5 months (95 % CI 3.4-5.4)), compared to those with intermediate or low TIMP-1 levels (7.8 months (95 % CI 4.4-13.7) and 12.0 months (95 % CI 10.1-14.3), respectively, p < 0.0001). An 83 % higher hazard for death was revealed (HR = 1.83) with each twofold increase in the TIMP-1 level. Pre-treatment levels of CEA were not associated with any of the baseline characteristics (except primary tumour localisation) or to differences in PFS or OS. The rank correlation between CEA and TIMP-1 was r = 0.50, and a test for interaction between TIMP-1 and CEA (dichotomised at 5 ng/ml) in survival analysis was not significant (p = 0.18). A multivariate analysis for PFS and OS resulted in a model with significant contributions from TIMP-1, KRAS, and the number of metastatic sites. We have confirmed the potential prognostic value of TIMP-1 measurement prior to palliative chemotherapy for mCRC. However, validation in randomised trials will be essential with the perspective of establishing a potential predictive role of plasma TIMP-1 in this setting.

TIMP-1 increases expression and phosphorylation of proteins associated with drug resistance in breast cancer cells

Tissue inhibitor of metalloproteinase 1 (TIMP-1) is a protein with a potential biological role in drug resistance. To elucidate the unknown molecular mechanisms underlying the association between high TIMP-1 levels and increased chemotherapy resistance, we employed SILAC-based quantitative mass spectrometry to analyze global proteome and phosphoproteome differences of MCF-7 breast cancer cells expressing high or low levels of TIMP-1. In TIMP-1 high expressing cells, 312 proteins and 452 phosphorylation sites were up-regulated. Among these were the cancer drug targets topoisomerase 1, 2A, and 2B, which may explain the resistance phenotype to topoisomerase inhibitors that was observed in cells with high TIMP-1 levels. Pathway analysis showed an enrichment of proteins from functional categories such as apoptosis, cell cycle, DNA repair, transcription factors, drug targets and proteins associated with drug resistance or sensitivity, and drug transportation. The NetworKIN algorithm predicted the protein kinases CK2a, CDK1, PLK1, and ATM as likely candidates involved in the hyperphosphorylation of the topoisomerases. Up-regulation of protein and/or phosphorylation levels of topoisomerases in TIMP-1 high expressing cells may be part of the mechanisms by which TIMP-1 confers resistance to treatment with the widely used topoisomerase inhibitors in breast and colorectal cancer.

TIMP1 overexpression mediates resistance of MCF-7 human breast cancer cells to fulvestrant and down-regulates progesterone receptor expression

High levels of Tissue Inhibitor of Metalloproteinases-1 (TIMP1) are associated with poor prognosis, reduced response to chemotherapy, and, potentially, also poor response to endocrine therapy in breast cancer patients. Our objective was to further investigate the hypothesis that TIMP1 is associated with endocrine sensitivity. We established a panel of 11 MCF-7 subclones with a wide range of TIMP1 mRNA and protein expression levels. Cells with high expression of TIMP1 versus low TIMP1 displayed significantly reduced sensitivity to the antiestrogen fulvestrant (ICI 182,780, Faslodex®), while TIMP1 levels did not influence the sensitivity to 4-hydroxytamoxifen. An inverse correlation between expression of the progesterone receptor and TIMP1 was found, but TIMP1 levels did not correlate with estrogen receptor levels or growth-promoting effects of estrogen (estradiol, E2). Additionally, the effects of fulvestrant, 4-hydroxytamoxifen, or estrogen on estrogen receptor expression were not associated with TIMP1 levels. Gene expression analyses revealed associations between expression of TIMP1 and genes involved in metabolic pathways, epidermal growth factor receptor 1/cancer signaling pathways, and cell cycle. Gene and protein expression analyses showed no general defects in estrogen receptor signaling except from lack of progesterone receptor expression and estrogen inducibility in clones with high TIMP1. The present study suggests a relation between high expression level of TIMP1 and loss of progesterone receptor expression combined with fulvestrant resistance. Our findings in vitro may have clinical implications as the data suggest that high tumor levels of TIMP1 may be a predictive biomarker for reduced response to fulvestrant.