Establishment of a 3D co-culture model to investigate the role of primary fibroblasts in ductal carcinoma in situ of the breast.

BACKGROUND: Ductal carcinoma in situ (DCIS) is a precursor form of breast cancer. 13%-50% of these lesions will progress to invasive breast cancer, but the individual progression risk cannot be estimated. Therefore, all patients receive the same therapy, resulting in potential overtreatment of a large proportion of patients. AIMS: The role of the tumor microenvironment (TME) and especially of fibroblasts appears to be critical in DCIS development and a better understanding of their role may aid individualized treatment. METHODS AND RESULTS: Primary fibroblasts isolated from benign or malignant punch biopsies of the breast and MCF10DCIS.com cells were seeded in a 3D cell culture system. The fibroblasts were cultured in a type I collagen layer beneath a Matrigel layer with MCF10DCIS.com cells. Dye-quenched (DQ) fluorescent collagen I and IV were used in collagen and Matrigel layer respectively to demonstrate proteolysis. Confocal microscopy was performed on day 2, 7, and 14 to reveal morphological changes, which could indicate the transition to an invasive phenotype. MCF10DCIS.com cells form smooth, round spheroids in co-culture with non-cancer associated fibroblasts (NAFs). Spheroids in co-culture with tumor-associated fibroblasts (TAFs) appear irregularly shaped and with an uneven surface; similar to spheroids formed from invasive cells. Therefore, these morphological changes represent the progression of an in situ to an invasive phenotype. In addition, TAFs show a higher proteolytic activity compared to NAFs. The distance between DCIS cells and fibroblasts decreases over time. CONCLUSION: The TAFs seem to play an important role in the progression of DCIS to invasive breast cancer. The better characterization of the TME could lead to the identification of DCIS lesions with high or low risk of progression. This could enable personalized oncological therapy, prevention of overtreatment and individualized hormone replacement therapy after DCIS.

The heparan sulphate proteoglycan Syndecan-1 (CD138) regulates tumour progression in a 3D model of ductal carcinoma in situ of the breast.

Ductal carcinoma in situ (DCIS) is a form of breast cancer that is restricted to the lactiferous ducts and has not yet invaded the surrounding breast tissue. Dysregulation of the transmembrane heparan sulphate proteoglycan Syndecan-1 (Sdc-1) plays a role in tumour progression of invasive breast cancer (IBC). In DCIS, Sdc-1, c-Met and E-cadherin are part of a proangiogenic expression signature. In this study, we employed a siRNA knockdown approach in the DCIS model cell line MCF10A DCIS.com to investigate a potential connection between Sdc-1 and epithelial mesenchymal transition (EMT), proteolysis and the Rho kinase pathway. Analysis of gene expression data of the TNMplot.com database revealed that Sdc-1 expression was higher in primary breast tumours compared to metastases. The impact of Sdc-1-depletion on the cellular phenotype was investigated in a Matrigel-based three-dimensional cell culture model. Sdc-1 depletion resulted in the formation of larger spheroids and the formation of invasive protrusions. Application of matrix metalloproteinase (MMP) and Rho kinase inhibitors could block the Sdc-1-induced phenotype. qPCR analysis of Sdc-1-depleted cells in two-dimensional culture revealed upregulated expression of the EMT-markers CDH1, FN-1, CLDN1, the proteolysis markers MMP3, and MMP9, and HPSE, while MMP2, VIM and ROCK-2 were downregulated. Immunocytochemistry confirmed upregulation of MMP9 and fibronectin, the latter being particular prominent after ROCK inhibition. STRING analysis confirmed an interaction of the investigated gene products at the protein level. Our results suggest that diminished Sdc-1 expression plays a role in DCIS progression to IBC through deregulation of proteolytic factors and a partial EMT.

Outbreak of MRSA in a Gynecology/Obstetrics Department during the COVID-19 Pandemic: A Cautionary Tale.

Since March 2020, the COVID-19 pandemic forced hospitals worldwide to intensify their infection control measures to prevent health care-associated transmission of SARS-CoV-2. The correct use of personal protective equipment, especially the application of masks, was quickly identified as priority to reduce transmission with this pathogen. Here, we report a nosocomial cluster of methicillin-resistant Staphylococcus aureus (MRSA) that occurred during the COVID-19 pandemic in a gynecology/obstetrics department, despite these intensified contact precautions. Five MRSA originating from clinical samples after surgical intervention led to an outbreak investigation. Firstly, this included environmental sampling of the operation theatre (OT) and, secondly, a point prevalence screening of patients and health care workers (HCW). All detected MRSA were subjected to whole genome sequencing (WGS) and isolate relatedness was determined using core genome multilocus sequence typing (cgMLST). WGS revealed one MRSA cluster with genetically closely related five patient and two HCW isolates differing in a single cgMLST allele at maximum. The outbreak was terminated after implementation of infection control bundle strategies. Although contact precaution measures, which are also part of MRSA prevention bundle strategies, were intensified during the COVID-19 pandemic, this MRSA outbreak could take place. This illustrates the importance of adherence to classical infection prevention strategies.

Collagen I triggers directional migration, invasion and matrix remodeling of stroma cells in a 3D spheroid model of endometriosis.

Endometriosis is a painful gynecological condition characterized by ectopic growth of endometrial cells. Little is known about its pathogenesis, which is partially due to a lack of suitable experimental models. Here, we use endometrial stromal (St-T1b), primary endometriotic stromal, epithelial endometriotic (12Z) and co-culture (1:1 St-T1b:12Z) spheroids to mimic the architecture of endometrium, and either collagen I or Matrigel to model ectopic locations. Stromal spheroids, but not single cells, assumed coordinated directional migration followed by matrix remodeling of collagen I on day 5 or 7, resembling ectopic lesions. While generally a higher area fold increase of spheroids occurred on collagen I compared to Matrigel, directional migration was not observed in co-culture or in 12Z cells. The fold increase in area on collagen I was significantly reduced by MMP inhibition in stromal but not 12Z cells. Inhibiting ROCK signalling responsible for actomyosin contraction increased the fold increase of area and metabolic activity compared to untreated controls on Matrigel. The number of protrusions emanating from 12Z spheroids on Matrigel was decreased by microRNA miR-200b and increased by miR-145. This study demonstrates that spheroid assay is a promising pre-clinical tool that can be used to evaluate small molecule drugs and microRNA-based therapeutics for endometriosis.

Ribociclib in Breast Cancer Brain Metastases: A Case Report.

INTRODUCTION: Breast cancer is the most common cancer in women. It frequently metastasizes to the lung, liver, and bones. Due to the improvement of therapeutic strategies and therefore longer patient survival, brain metastases have become more frequent. However, evidence-based therapeutic options of systemic treatment are limited because patients with breast cancer brain metastases are often excluded from clinical trials. CASE PRESENTATION: Here, we show a patient with brain and orbital metastases from a hormone receptor-positive, Her2neu-negative breast cancer that led to one-sided blindness. She was treated with a combination therapy of the CDK4/6 inhibitor ribociclib and the aromatase inhibitor anastrozole and showed a fast and durable response for 9 months with good tolerability of the treatment. CONCLUSION: Systemic treatment with a CDK4/6 inhibitor and endocrine therapy can be considered in breast cancer brain metastases.

Correlation between SFRP1 expression and clinicopathological parameters in patients with triple-negative breast cancer.

Aim: Breast cancer is a heterogeneous disease with distinct molecular and clinical behavior demanding reliable biomarkers, especially in triple-negative breast cancer (TNBC). This study seeks to improve the understanding of SFRP1 as a potential biomarker in breast cancer focusing on TNBC. Materials & methods: SFRP1 expression was investigated via immunohistochemistry with two anti-SFRP1-antibodies on tissue-microarrays of 376 invasive breast cancers. Results: Statistical analysis revealed a highly significant association between TNBC (n = 36) and SFRP1 expression (p < 0.001). SFRP1 expression was significantly associated with younger age, higher tumor stage, size and grade. Conclusion: SFRP1 expression is strongly correlated with TNBC on protein level. Associations with age and tumor grade support the role of SFRP1 as a biomarker for chemotherapy response in TNBC.

Increased epigenetic age in normal breast tissue from luminal breast cancer patients.

BACKGROUND: Age is one of the most important risk factors for developing breast cancer. However, age-related changes in normal breast tissue that potentially lead to breast cancer are incompletely understood. Quantifying tissue-level DNA methylation can contribute to understanding these processes. We hypothesized that occurrence of breast cancer should be associated with an acceleration of epigenetic aging in normal breast tissue. RESULTS: Ninety-six normal breast tissue samples were obtained from 88 subjects (breast cancer = 35 subjects/40 samples, unaffected = 53 subjects/53 samples). Normal tissue samples from breast cancer patients were obtained from distant non-tumor sites of primary mastectomy specimens, while samples from unaffected women were obtained from the Komen Tissue Bank (n = 25) and from non-cancer-related breast surgery specimens (n = 28). Patients were further stratified into four cohorts: age < 50 years with and without breast cancer and age ≥ 50 with and without breast cancer. The Illumina HumanMethylation450k BeadChip microarray was used to generate methylation profiles from extracted DNA samples. Data was analyzed using the "Epigenetic Clock," a published biomarker of aging based on a defined set of 353 CpGs in the human genome. The resulting age estimate, DNA methylation age, was related to chronological age and to breast cancer status. The DNAmAge of normal breast tissue was strongly correlated with chronological age (r = 0.712, p < 0.001). Compared to unaffected peers, breast cancer patients exhibited significant age acceleration in their normal breast tissue (p = 0.002). Multivariate analysis revealed that epigenetic age acceleration in the normal breast tissue of subjects with cancer remained significant after adjusting for clinical and demographic variables. Additionally, smoking was found to be positively correlated with epigenetic aging in normal breast tissue (p = 0.012). CONCLUSIONS: Women with luminal breast cancer exhibit significant epigenetic age acceleration in normal adjacent breast tissue, which is consistent with an analogous finding in malignant breast tissue. Smoking is also associated with epigenetic age acceleration in normal breast tissue. Further studies are needed to determine whether epigenetic age acceleration in normal breast tissue is predictive of incident breast cancer and whether this mediates the risk of chronological age on breast cancer risk.

Tumor-Infiltrating Lymphocytes and PD-L1 Expression in Pre- and Posttreatment Breast Cancers in the SWOG S0800 Phase II Neoadjuvant Chemotherapy Trial.

Our aim was to examine the association of pretreatment tumor-infiltrating lymphocyte (TIL) count and PD-L1 levels with pathologic complete response (pCR) and assess immune marker changes following treatment in tumor specimens from the S0800 clinical trial, which randomized patients to bevacizumab + nab-paclitaxel, followed by doxorubicin/cyclophosphamide (AC) versus two control arms without bevacizumab (varying sequence of AC and nab-paclitaxel). TILs were assessed in 124 pre- and 62 posttreatment tissues (including 59 pairs). PD-L1 was assessed in 120 pre- and 43 posttreatment tissues (including 39 pairs) using the 22C3 antibody. Baseline and treatment-induced immune changes were correlated with pCR and survival using estrogen receptor (ER) and treatment-adjusted logistic and Cox regressions, respectively. At baseline, the mean TIL count was 17.4% (17% had zero TILs, 9% had ≥50% TILs). Posttreatment, mean TIL count decreased to 11% (5% had no TILs, 2% had >50% TILs). In paired samples, the mean TIL change was 15% decrease. Baseline PD-L1 was detected in 43% of cases (n = 5 in tumor cells, n = 29 stroma, n = 18 tumor + stroma). Posttreatment, PD-L1 expression was not significantly lower (33%). Higher baseline TIL count and PD-L1 positivity rate were associated with higher pCR rate even after adjustment for treatment and ER status (P = 0.018). There was no association between TIL counts, PD-L1 expression, and survival due to few events. In conclusion, TIL counts, but not PD-L1 expression, decreased significantly after treatment. Continued PD-L1 expression in some residual cancers raises the possibility that adjuvant immune checkpoint inhibitor therapy could improve survival in this patient population. Mol Cancer Ther; 17(6); 1324-31. ©2018 AACR.

Reverse engineering of triple-negative breast cancer cells for targeted treatment.

OBJECTIVE: Targeting the human epidermal growth factor receptor HER2 has increased survival in HER2-positive breast cancer patients. In the contrast, for triple-negative breast cancer (TNBC) patients, no targeted agents are available. We hypothesized that artificial overexpression of HER2 in TNBC cells might induce sensitivity to anti-HER2 agents in these cells. METHODS: TNBC cell lines were transduced using lentiviral HER2 overexpression particles. Functionality of HER2 was determined by protein analysis and localization studies. The tumorigenic potential of HER2 overexpressing cells was assessed by analysis of proliferation, migration and invasion capacity. Response to chemotherapeutic agents and anti-HER2 agents was determined by cell viability assays. RESULTS: We demonstrated functional overexpression of HER2 in TNBC cell lines of different subtypes. Whereas in cell types with more pronounced epithelial features (e.g. MDA-MB-468) HER2 overexpression increases proliferation and migration, in mesenchymal cell lines (MDA-MB-231 and BT-549) HER2 was able to further increase invasive potential. No changes were found in cancer stem cell characteristics or in response to chemotherapy, a trait of TNBC. When treated with anti-HER2 agents, however, HER2 overexpressing TNBC cells showed increased sensitivity to these agents. CONCLUSION: This proof-of-principle study demonstrates that reverse engineering of TNBC cells might offer a novel targeted treatment strategy for this most aggressive subtype of breast cancer.

Intratumor Heterogeneity of Homologous Recombination Deficiency in Primary Breast Cancer.

Purpose: The 3-biomarker homologous recombination deficiency (HRD) assay measures the number of telomeric allelic imbalances, loss of heterozygosity, and large-scale state transitions in tumor DNA and combines these metrics into a single score that reflects DNA repair deficiency. The goal of this study is to assess the consistency of these HRD measures in different biopsies from distinct areas of the same cancer.Experimental Design: HRD scores, BRCA mutation status, and BRCA1 promoter methylation were assessed in 99 samples from 33 surgically resected, stage I-III breast cancers; each cancer was biopsied in three distinct areas. Homologous recombination repair (HR) deficiency was defined as either high HRD score (≥42) or tumor BRCA mutation.Results: Eighty-one biopsies from 32 cancers were analyzed. Tumor BRCA status was available for all samples, HRD scores for 70, and BRCA1 methylation values for 76 samples. The BRCA1/2 mutation and promoter methylation status and HR category showed perfect concordance across all biopsies from the same cancer. All tumors with BRCA1/2 mutations or promoter methylation had high HRD scores, as did 17% (4/24) of the BRCA1/2 wild-type and nonmethylated tumors. The HRD scores were also highly consistent between different biopsies from the same tumor with an intraclass correlation coefficient of 0.977, indicating that only 2.3% of the variance is attributed to within-tumor biopsy-to-biopsy variation.Conclusions: These results indicate that within-tumor spatial heterogeneity for HRD metrics and the technical noise in the assay are small and do not influence HRD scores and HR status. Clin Cancer Res; 23(5); 1193-9. ©2016 AACR.

The anti-androgen drug dutasteride renders triple negative breast cancer cells more sensitive to chemotherapy via inhibition of HIF-1α-/VEGF-signaling.

BACKGROUND: Triple negative breast cancer (TNBC) is characterized by lack of expression of both estrogen and progesterone receptor as well as lack of amplification of HER2. Patients with TNBC carry an unfavorable prognosis compared to other breast cancer subtypes given that endocrine or HER2 targeted therapies are not effective, rendering chemotherapy the sole effective treatment option to date. Therefore, there is a high demand for additional novel treatment options. FINDINGS: We previously published a list of genes showing both higher gene expression rates in TNBC and, in addition, are known to encode targets of non-oncologic drugs. SRD5A1, which encodes the type-1 isoform of the steroid-5alpha-reductase, which is involved in androgen metabolism, was found to be one of these genes. Dutasteride is a dual blocker of both the type-1 and type-2 isoform of SRD5A1 and is indicated in the treatment of benign prostate hyperplasia. Treatment of TNBC cell lines with dutasteride was associated with a dose-dependent decrease in cell viability, altered protein expression of VEGF and HIF-1α and increased chemosensitivity. CONCLUSION: Our results demonstrate that the SRD5A1-corresponding anti-androgenic drug dutasteride might act as a combinatorial therapeutic option besides standard chemotherapy in highly aggressive TNBC.