FOXP3+ Tregs and B7-H1+/PD-1+ T lymphocytes co-infiltrate the tumor tissues of high-risk breast cancer patients: Implication for immunotherapy

<p>Abstract</p> <p>Background</p> <p>Recent studies have demonstrated a direct involvement of B7-H1, PD-1 and FOXP3 molecules in the immune escape of cancer. B7-H1 is an inhibitory molecule that binds to PD-1 on T lymphocytes, while FOXP3 is a marker for regulatory T cells (T_regs). We have previously demonstrated the association of B7-H1-expressing T infiltrating lymphocytes (TIL) with high-risk breast cancer patients while other studies reported the involvement of FOXP3+ T_regsas a bad prognostic factor in breast tumors. Although the co-existence between the two types of cells has been demonstrated <it>in vitro </it>and animal models, their relative infiltration and correlation with the clinicopathological parameters of cancer patients have not been well studied. Therefore, we investigated TIL-expressing the B7-H1, PD-1, and FOXP3 molecules, in the microenvironment of human breast tumors and their possible association with the progression of the disease.</p> <p>Methods</p> <p>Using immunohistochemistry, tumor sections from 62 breast cancer patients were co-stained for B7-H1, PD-1 and FOXP3 molecules and their expression was statistically correlated with factors known to be involved in the progression of the disease.</p> <p>Results</p> <p>A co-existence of B7-H1⁺T lymphocytes and FOXP3⁺T_regswas evidenced by the highly significant correlation of these molecules (<it>P </it>< .0001) and their expression by different T lymphocyte subsets was clearly demonstrated. Interestingly, concomitant presence of FOXP3⁺T_regs, B7-H1⁺and PD-1⁺TIL synergistically correlated with high histological grade (III) (<it>P </it>< .001), estrogen receptor negative status (<it>P </it>= .017), and the presence of severe lymphocytic infiltration (<it>P </it>= .022).</p> <p>Conclusion</p> <p>Accumulation of TIL-expressing such inhibitory molecules may deteriorate the immunity of high-risk breast cancer patients and this should encourage vigorous combinatorial immunotherapeutic approaches targeting T_regsand B7-H1/PD-1 molecules.</p

Abstract P4-05-02: Role of the Atr Protein Kinase and Curcumin in Tumor-Stromal Interactions in Breast Cancer

Abstract Carcinoma-associated fibroblasts (CAFs) play important roles in the genesis and thrive of various types of epithelial cancers, including breast carcinomas. Indeed, various genetic and epigenetic variations have been identified in stromal fibroblasts, and we have recently shown that CAFs as well as their corresponding counterparts (TCFs) display neoplastic-specific changes (Hawsawi et al., 2008). We have also shown that the levels of the tumor suppressor proteins p53 and p21 are down-regulated in CAFs as compared to TCFs. During the cellular response to DNA damage these genes are under the control of important proteins such as Atr, a protein kinase essential for the maintenance of genomic integrity. To further elucidate the molecular changes that occur in breast cancer-associated fibroblasts we assessed the expression of Atr and have shown that the level of the Atr protein kinase is lower in 7 out of 10 (70%) CAFs as compared to their corresponding TCFs. Using specific ATR-siRNA we have shown that ATR negatively controls the expression of various proteins involved in the stromal-epithelial interactions. These include the stromal cell-derived factor 1 (SDF1), the vascular endothelial growth factor (VEGF) and the matrix metalloproteinase-2 (MMP2). In addition, the ELISA assay was used to show that the level of these proteins was higher in the conditioned media from stromal fibroblasts expressing specific ATR-siRNA as compared to control cells. Importantly, serum-free conditioned media from ATR-defective cells stimulated the proliferation and invasion/migration of cultured human breast cancer cells in an SDF1-dependent manner. These results clearly show the role of the breast stromal fibroblast Atr protein in suppressing tumoregenesis in the breast. Moreover, we have shown that curcumin can normalize the expression/secretion of these factors and therefore reduces the invasion/migration of breast cancer cells in vitro. This indicates that curcumin has potential use as stromal fibroblastnormalizing factor that can be utilized for the inhibition of both cancer initiation and recurrence. Hawsawi, N. M., Ghebeh, H., Hendrayani, S. F., Tulbah, A., Al-Eid, M., Al-Tweigeri, T., Ajarim, D., Alaiya, A., Dermime, S., and Aboussekhra, A. (2008). Cancer Res 68, 2717-2725. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P4-05-02.</jats:p

TP53 genetic alterations in Arab breast cancer patients: Novel mutations, pattern and distribution

Breast cancer remains a worldwide public health concern. The incidence and mortality of breast cancer varies significantly in ethnically and geographically distinct popula-tions. In the Kingdom of Saudi Arabia (KSA) breast cancer has shown an increase in incidence and is characterized by early onset and aggressiveness. The tumor suppressor TP53 gene is a crucial genetic factor that plays a significant role in breast carcinogenesis. Furthermore, studies have shown a correla¬tion between certain p53 mutations and response to therapy in breast cancer. In the present study, TP53 mutations were identified by direct sequencing of the gene (exons 4-9) from 119 breast cancer tissues. The prevalence of TP53 mutations in Arab breast cancer patients living in the KSA is among the highest in the world (40%). Notably, 73% of the patients whose tumors harbored p53 mutations were less than 50 years of age. Furthermore, for the first time, we identified 7 novel mutations and 16 mutations in breast cancer tissues. Notably, all the novel point mutations were found in exon 4, wherein 29% of the mutations were localized. Furthermore, an excess of G:C→A:T transitions (49%) at non-CpG sites was noted, suggesting exposure to particular environmental carcinogens such as N-nitroso compounds. The results indicate that the TP53 gene plays a significant role in breast carcinogenesis and the early onset of the disease among Arab female individuals.King Saud Universit

Fascin is involved in the chemotherapeutic resistance of breast cancer cells predominantly via the PI3K/Akt pathway

BACKGROUND: A major therapeutic challenge for breast cancer is the ability of cancer cells to evade killing of conventional chemotherapeutic agents. We have recently reported the actin-bundling protein (fascin) as a major regulator of breast cancer metastasis and survival. METHODS: Survival of breast cancer patients that received chemotherapy and xenograft tumour model was used to assess the effect of chemotherapy on fascin-positive and -negative breast cancer cells. Molecular and cellular assays were used to gain in-depth understanding of the relationship between fascin and chemoresistance. RESULTS: We showed a significant correlation between fascin expression and shorter survival in breast cancer patients who received chemotherapy. In xenograft experiments, fascin-positive cancer cells displayed significantly more resistance to chemotherapy-mediated apoptotic cell death than fascin-negative counterparts. This increased chemoresistance was at least partially mediated through PI3K/Akt signalling, and was paralleled by increased FAK phosphorylation, enhanced expression of the inhibitor of apoptosis proteins (XIAP and Livin) and suppression of the proapoptotic markers (caspase 9, caspase 3 and PARP). CONCLUSIONS: This is the first report to demonstrate fascin involvement in breast cancer chemotherapeutic resistance, supporting the development of fascin-targeting drugs for better treatment of chemoresistance breast cancer