Nuclear Receptors Are Differentially Expressed and Activated in KAIMRC1 Compared to MCF7 and MDA-MB231 Breast Cancer Cells.

We recently established a KAIMRC1 cell line that has unique features compared to the known breast cancer cell lines, MCF7 and MDA-MB231. To characterize it further, we investigated the expression profile of nuclear receptors and their respective co-factors in these cell lines. We confirm that in contrast to the triple negative cell line MDA-MB231, the MCF7 and KAIMRC1 are estrogen receptor alpha (ERa) and progesterone receptor alpha (PRa) positive, with significant lower expression of these receptors in KAIMRC1. KAIMRC1 cell is a vitamin D receptor (VDR) negative and V-ErbA-Related Protein 2 (EAR2) positive in contrast to MCF7 and MDA-MB231. Remarkably, the histone deacetylases (HDACs) are highly expressed in KAIRMC1 with HDAC6 and HDAC 7 are exclusively expressed in KAIMRC1 while thyroid hormone receptor-associated protein 80 (TRAP80), telomeric DNA binding protein 1 (TBP1) and TGF-beta receptor interacting protein (TRIP1) are absent in KAIMRC1 but present in MCF7 and MDA-MB231. In a luciferase reporter assay, the ERa coexpression is needed for estrogen receptor element (ERE)-luciferase activation by estradiol in KAIMRC1 but not in MCF7. The co-expression of exogenous Liver X receptor alpha (LXRa)/retinoid X receptor alpha (RXRa) are necessary for LXR responsive element (LXRE) activation by the GW3696 in the three cell lines. However, the activity of peroxisome proliferator-activated receptor response element (PPARE)-tk-luciferase reporter increased when peroxisome proliferator-activated receptors alpha (PPARa)/RXRa were coexpressed but the addition of PPARa agonist (GW7647) did not stimulate further the reporter. The signal of the PPARE reporter increased in a dose-dependent manner with rosiglitazone (PPARg agonist) in KAIMRC1, MCF7, and MDA-MB231 when the proliferator-activated receptors gamma (PPARg)/RXRa receptors were cotransfected. Retinoic acid-induced activation of retinoic acid receptor response element (RARE)-tk-luciferase is dependent on exogenous expression of retinoic acid receptor alpha (RARa)/RXRa heterodimer in MDA-MB 231 but not in MCF7 and KAIMRC1 cell lines. In the three cell lines, Bexarotene-induced retinoid X receptor response element (RXRE)-luciferase reporter activation was induced only if the RXRa/LXRa heterodimer were co-expressed. The vitamin D receptor response element (VDRE)-luciferase reporter activity showed another distinct feature of KAIMRC1, where only co-expression of exogenous vitamin D receptor (VDR)/RXRa heterodimer was sufficient to reach the maximum rate of activation of VDRE reporter. In the proliferation assay, nuclear receptors ligands showed a distinct effect on KAIMRC1 compared to MCF7 and MDA-MB231. Growth inhibition effects of used ligands suggest that KAIMRC1 correlate more closely to MDA-MB231 than MCF7. Vitamin D3, rosiglitazone, novel RXR compound (RXRc) and PPARa compound (GW6471) have the most profound effects. In conclusion, we showed that nuclear receptors are differentially expressed, activated and also their ligand produced distinct effects in KAIMRC1 compared to MCF7 and MDA-MB231. This finding gives us confidence that KAIMRC1 has a unique biological phenotype.

Isolation and characterization of a new naturally immortalized human breast carcinoma cell line, KAIMRC1.

BACKGROUND: Breast cancer is one of the most common cancer and a leading cause of death in women. Up to date the most commonly used breast cancer cell lines are originating from Caucasians or Afro-Americans but rarely cells are being derived from other ethnic groups. Here we describe for the first time the establishment of a naturally transformed breast cancer cell line, KAIMRC1 from an Arab woman of age 62 suffering from stage IIB breast cancer (T2N1M0). Moreover, we have characterized these cells for the biological and molecular markers, induction of MAPK pathways as well as its response to different commercially available drugs and compounds. METHODS: Breast cancer tissue sections were minced and cultured in media for several weeks. KAIMRC1 cells were successfully isolated from one of the primary breast tumor tissue cultures without any enzymatic digestion. To study the growth characteristics of the cells, wound healing assay, clonogenic assay, cell proliferation assays and live cell time-lapse microscopy was performed. Karyotyping, Immunophenotyping and molecular pathway specific compound treatment was also performed. A selective breast cancer gene expression panel was used to identify genes involved in the signal transduction dysregulation and malfunction of normal biological processes during breast carcinogenesis. RESULTS: These cells are ER/PR-positive and HER2-negative. The epithelial nature of these cells was confirmed by flow cytometry analysis using epithelial cell markers. They are cuboidal in shape and relatively smaller in size as compared to established cell lines, MCF-7, MDA MB-231 and the normal breast cell line, MCF-10A. In normal cell culture conditions these cells showed the capability of growing both in monolayer as well as in 3-D conformation. They showed a doubling time in vitro of approximately 24 h. They exhibit a modal karyotype of 58-63,X with abnormalities in a couple of chromosomes. KAIMRC1 cells were found to be more responsive to drug treatment in vitro in comparison to the established MDA MB-231 and MCF-7 cell lines. CONCLUSIONS: In conclusion we have isolated and characterized a new naturally immortalized breast cell line, KAIMRC1 with a potential to play a key role in opening up novel avenues towards the understanding of breast carcinoma.

Descriptive Study and Surgical Management Among Infiltrating Lobular Carcinoma Patients Admitted to King Abdulaziz Medical City From 2000 to 2017: A Retrospective Cross-Sectional Study.

INTRODUCTION: Invasive lobular carcinoma (ILC) is the second most common histologic type of breast carcinoma. The etiology of ILC is unknown; however, many contributing risk factors have been suggested. Treatment of ILC can be divided into local and systemic. Our objectives were to assess the clinical presentations, risk factors, radiological findings, pathological types, and surgical options for patients with ILC treated at the national guard hospital. Identify the factors associated with metastasis and recurrence. METHODS: Retrospective cross-sectional descriptive study at a tertiary care center in Riyadh. All adult patients aged 16 years and above, from different nationalities, and both genders, were diagnosed with ILC from 2000 to 2017 and followed up at KAMC. The sampling technique was a non-probability consecutive technique. Among 1066 patients identified, 91 patients were diagnosed with ILC over seventeen years study period. RESULTS: The median age at the primary diagnosis was 50. On the clinical examination, 63 (71%) cases were found to have palpable masses which was the most suspicious finding. On radiology, the most encountered finding was speculated masses which were seen in 76 (84%). Regarding the pathology, unilateral breast cancer was seen in 82 while bilateral breast cancer was found only in eight. For the biopsy, a core needle biopsy was the most commonly used in 83 (91%) patients. The most documented surgery for ILC patients was a modified radical mastectomy. Metastasis in different organs was identified with the musculoskeletal system being the commonest site. Different significant variables were compared between patients with or without metastasis. Skin changes, post-operative invasion, estrogen, progesterone, and HER2 receptors were significantly associated with metastasis. Patients with metastasis were less likely to have conservative surgery. Regarding the Recurrence and five years survival, out of 62 cases, 10 had recurrence within five years, which was more prevalent in patients who had fine needle aspiration, excisional biopsy, and nulliparous patients. CONCLUSION: To our knowledge, this is the first study to exclusively describe ILC in Saudi Arabia. The results of this current study are highly important, as these results provide baseline data of ILC in the capital city of Saudi Arabia.