The goal of our study was to develop a panel of tumor cell lines along with paired non‐malignant cell lines or strains collected from breast cancers, predominantly primary tumors. From a total of 189 breast tumor samples consisting of 177 primary tumors and 12 metastatic tissues, we established 21 human breast tumor cell lines that included 18 cell lines derived from primary tumors and 3 derived from metastatic lesions. Cell lines included those from patients with germline BRCA1 and FHIT gene mutations and others with possible genetic predisposition. For 19 tumor cell lines, we also established one or more corresponding non‐malignant cell strains or B lymphoblastoid (BL) lines, which included 16 BL lines and 7 breast epithelial (2) or stromal (5) cell strains. The present report describes clinical, pathological and molecular information regarding the normal and tumor tissue sources along with relevant personal information and familial medical history. Analysis of the breast tumor cell lines indicated that most of the cell lines had the following features: they were derived from large tumors with or without axillary node metastases; were aneuploid and exhibited a moderate to poorly differentiated phenotype; were estrogen receptor (ER)‐ and progesterone receptor (PR)‐negative; and overexpressed p53 and HER2/neu proteins. Of 13 patients with primary breast cancers receiving curative intent mastectomies, 7 were dead after a mean period of 10 months. Our panel of paired tumor and non‐malignant cell lines should provide important new reagents for breast cancer research. Int. J. Cancer 78:766–774, 1998. © 1998 Wiley‐Liss, Inc.

No abstract

Individuals with germ line mutations in the p53 gene, such as Li-Fraumeni syndrome (LFS), have an increased occurrence of many types of cancer, including an unusually high incidence of breast cancer. This report documents that normal breast epithelial cells obtained from a patient with LFS (with a mutation at codon 133 of the p53 gene) spontaneously immortalized in cell culture while the breast stromal fibroblasts from this same patient did not. Spontaneous immortalization of human cells in vitro is an extremely rare event. This is the first documented case of the spontaneous immortalization of breast epithelial cells from a patient with LFS in culture. LFS patient breast stromal fibroblasts infected with a retroviral vector containing human papillomavirus type 16 E7 alone were able to immortalize, whereas stromal cells obtained from patients with wild-type p53, similarly infected with human papillomavirus type 16 E7, did not. The present results indicate a protective role of normal pRb-like functions in breast stromal fibroblasts but not in breast epithelial cells and reinforces an important role of wild-type p53 in the regulation of the normal growth and development of breast epithelial tissue.Familial cancer syndromes with germ line mutations, such as the dominantly inherited p53 mutations present in Li-Fraumeni syndrome (LFS), have helped to illustrate the important role of tumor suppressor genes in the development of human cancers (3,30,31,35,36,37,52). The p53 gene is presently considered to be one of the most frequently mutated genes in human cancer (19,22,28,29,47,56,58), and the functional effects of mutations in evolutionarily conserved regions of the p53 phosphoprotein are currently a subject of intense study (24,25,28,43,46,(59)(60)(61)(62)(63). While a complete understanding of wild-type p53 function is not yet known, it is generally believed that perturbations of wild-type p53 function may lead to genomic instability and permit the expansion of the pool of proliferating cells, which leads to a cascade of additional mutations, increasing the probability of neoplastic transformation. The discovery of the importance of the tumor suppressor gene p53, and the identification of germ line mutations in p53 in LFS-affected families, has led to a growing awareness of the cancer risk to such families. Even though rare bone and soft tissue sarcomas are relatively common in families affected by LFS, other, more frequently occurring forms of cancer other than breast cancer (such as colorectal carcinoma) are not overrepresented. Among women in families affected by LFS, breast tumors are the most prevalent cancer (afflicting at least 50%), with 28% of the breast cancers diagnosed before age 30 and 89% diagnosed before age 50 (21, 31, 37). A molecular explanation for the specifically increased incidence of breast cancer, particularly early-onset breast cancer, in families affected by LFS relative to other forms of cancer has not yet been elucidated (20, 41).We and others have shown that spontaneous immortalization ...

Although the anticancer drugs paclitaxel and doxorubicin are commonly used to treat many solid tumors, their effectiveness is highly variable due to tumor cell resistance. Therefore, it is important to find mechanisms that can be targeted to increase the sensitivity of cancer cells to current chemotherapeutic agents. NIMA-related kinase 2 (Nek2), a serine/threonine kinase is emerging as an important oncogene because of its regulatory role in mitosis. Thus, regulation of the Nek2 expression levels may prove important as a target for cancer treatment. The purpose of our study was to determine whether drug sensitivity was increased in the triple negative breast cancer cell lines MDA-MB-231 and MDA-MB-468 by using small interfering RNA (siRNA) and antisense oligo-nucleotides (ASOs) against Nek2. To this end, MDA-MB-231 and MDA-MB-468 breast cancer cells transfected with Nek2 siRNA or ASO were exposed to various concentrations of paclitaxel and doxorubicin. Cell viability, cell cycle distribution and apoptosis were evaluated. We observed that drug susceptibility in these transfected cells was dramatically increased compared with either agent alone. FACS results showed that apoptosis was induced in siRNA- and ASO-transfected cells as expected due to the regulatory function of Nek2 in centrosome duplication. Interestingly, the cell cyle was not arrested in transfected cells. We found that siRNA and ASO against Nek2 worked synergistically with paclitaxel and doxorubicin by promoting cell apoptosis. Our results suggest that these drugs in combination with Nek2 siRNA or ASO treatment may improve the sensitivity of cancer cells during chemotherapy treatments.

Li-Fraumeni Syndrome (LFS) is characterized by heterozygous germline mutations in the p53 gene. Accompanied by genomic instability and loss or mutation of the remaining wild type p53 allele, a low frequency of spontaneous immortalization in LFS ®broblasts occurs. It is believed that the loss of p53 wild type function contributes to immortalization of these LFS ®broblasts, but it is not clear if this is su cient. Because stabilization of telomere length is also thought to be a necessary step in immortalization, telomerase activity, expression of the telomerase RNA component (hTR) and telomere length were analysed at various passages during the spontaneous immortalization of LFS skin ®broblasts. One LFS strain which immortalized, MDAH087 (087), had no detectable telomerase activity whereas another LFS strain which immortalized, MDAH041 (041), had detectable telomerase activity. In preimmortal cells from both strains, hTR was not detected by in situ hybridization. Immortal 087 cells remained negative for hTR, while immortal 041 cells demonstrated strong hTR in situ hybridization signals. 087 cells had long and heterogenous telomeres whereas telomeres of 041 cells had short, stable telomere lengths. Tumorigenicity studies in nude mice with ras-transformed 087 and 041 cells resulted in both cell lines giving rise to tumors and retaining telomerase status. Overall these results suggest that strain speci®city may be important in telomerase re-activation and that both abrogation of p53 function and a mechanism to maintain telomeres are necessary for immortalization.