Kathy McDaniel

Investigation into the Mechanism of the Loss of Laminin 5 (α3β3γ2) Expression in Prostate Cancer

Laminin 5 is a pivotal hemidesmosomal protein involved in cell stability, migration, and anchoring filament formation. Protein and gene expression of the α3, β3, and γ2 chains of laminin 5 were investigated in normal and invasive prostate carcinoma using immunohistochemistry, Northern analysis, and in situ hybridization. Laser capture microdissection of normal and carcinomatous glands, in conjunction with RNA amplification and reverse Northern analysis, were used to confirm the gene expression data. Protein and mRNA expression of all three laminin 5 chains were detected in the basal cells of normal glands. In contrast, invasive prostate carcinoma showed a loss of β3 and γ2 protein expression with variable expression of α3 chains. Despite the loss of protein expression, there was retention of β3 and γ2 mRNA expression as detected by in situ hybridization, Northern and reverse Northern analysis. Our findings imply that an altered mechanism of translation of β3 or γ2 mRNAs into functional proteins contributes to failure of anchoring filaments and hemidesmosomal formation. The resultant hemidesmosome instability or loss would suggest a less stable epithelial-stromal junction, increased invasion and migration of malignant cells, and disruption of normal integrin signaling pathways.

The Laminin Binding Integrin α6β1 in Prostate Cancer Perineural Invasion

Metastasizing prostate tumor cells invade along nerves innervating the encapsulated human prostate gland in a process known as perineural invasion. The extacellular matrix laminin class of proteins line the neural route and tumor cells escaping from the gland express the laminin binding integrin α6β1 as a prominent cell surface receptor. Integrin α6β1 promotes aggressive disease and supports prostate tumor cell metastasis to bone. Laminins and their integrin receptors are necessary for the development and maintenance of the peripheral nervous system, indicating the potential role for integrin receptors in directing prostate tumor cell invasion on nerves during perineural invasion. J. Cell. Physiol. 224: 283–288, 2010.

Differential localization of MT1-MMP in human prostate cancer tissue: role of IGF-1R in MT1-MMP expression.

MT1‐MMP is a metalloproteinase involved in prostate cancer metastasis. The IGF‐1R is a tyrosine kinase receptor involved with tumor progression and metastasis. The purpose of this investigation was to examine MT1‐MMP and IGF‐1R expression and localization in prostate cancer tissues and explore the role of IGF‐1R in regulating MT1‐MMP in prostate cancer cell lines.

Experimental induction of rhabdomyosarcoma in mice with fractionated doses of β-irradiation

Abstract Repeated doses of β-radiation in the mouse skin model have been reported to produce carcinomas and sarcomas with equal frequency. Among sarcomas, fibrosarcomas and osteosarcomas have been the predominant reported histologies. In this report we describe the β-radiation induction of rhabdomyosarcoma (RMS), a histology previously undescribed with tumor induction protocols using ionizing radiation in an animal model. Radiation-induced RMS is often seen as a secondary tumor following therapeutic irradiation for retinoblastoma in children. In our experiment the backs of 50 CD-1 mice were irradiated 3 times weekly for 35 weeks using a 90Sr source. The initial dose was 5.5 Gy/application, which was later reduced to 3 Gy after 15 weeks due to severe skin reactions. In all, 27 skin and subcutaneous tumors were seen and collected. Of 12 sarcomas seen, 9 had a rhabdoid histology; cell lines from 3 such tumors as well as a squamous-cell carcinoma (SCC) and a malignant fibrous histiocytoma (MFH) were established. Immunohistochemical analysis of their parent tumors showed that the rhabdoid tumors expressed desmin, which established the diagnosis of RMS. Two-dimensional gel electrophoresis and Western analysis of insoluble protein extracts confirmed that the cell lines from RMS tumors expressed desmin. A screen for molecular alterations identified a mutant p53 phenotype for RMS and MFH cell lines. These radiation-induced RMS cell lines provide a unique opportunity to study the molecular biology of this tumor in an animal model and will help provide insight into the mechanisms of radiation-induced RMS in humans.

Abstract 1543: Potential role of Schwann cells and laminin adhesion in prostate cancer perineural invasion

Prostate tumor cell migration and invasion of prostatic nerves, a process known as perineural invasion (PNI), is a major route for extracapsular extension during prostate cancer metastasis. The clinical significance of perineural invasion as a predictor for poor patient outcome has been extensively documented. The laminin family of extracellular matrix glycoproteins lines the neural route and plays a prominent role in the development and maintenance of the peripheral nervous system. Evidence has shown that the laminin receptor integrin α6β1 promotes prostate tumor cell migration and invasion in aggressive disease. We hypothesize that α6β1 regulates prostate cancer perineural invasion by regulating laminin dependent adhesion and migration on nerves. In this study we demonstrate remarkable integrin α6 expression in prostate tumors undergoing active perineural invasion using immunohistochemical analysis of human prostate tumors. The expression of integrin α6 correlates with expression of the laminin subunits α5 and γ1 which comprise laminin-511, the major ligand for integrin α6β1. The laminin extracellular matrix on the peripheral nerves of the prostate is derived from Schwann cells during the myelination process. We demonstrate here that Schwann cells are highly expressed in prostatic nerves using immunohistochemical analysis of the Schwann cell specific marker S-100, suggesting that tumor cells invade myelinated nerves. We also demonstrate two specific patterns of prostate tumor nerve invasion along prostatic nerves. Invasion along the external surface of the nerve sheath or in the perineural space maintains nerve structure while invasion of the endoneural space disrupts nerve structure and displaces Schwann cells. This suggests that tumor interactions with nerves and Schwann cells may illicit nerve damage during the PNI process. Using a DU-145 prostate tumor and neuron/glial cell in vitro co-culture model we demonstrate that DU-145 cells (cytokeratin positive) migrate towards glial cells (GFAP positive) and neurons (Beta-III tubulin positive) isolated from dorsal root ganglia of male SCID mice. Mature cultures of the prostate tumor cells and neuron/glial cells demonstrate distinct islands of growth. The patterns of colony formation were non-random and interspersed colonies of tumor and nerve cells were not observed. Taken together, our immunohistochemical results suggest that perineural invasion of laminin coated nerves is regulated by the laminin adhesion receptor α6β1. Our in vitro model system demonstrates that tumor cells migrate to neuron/glial cells and dominate the co-culture, correlating with our immunohistochemical data. We expect that blocking α6β1 function in this system will impede prostate tumor cell migration and invasion in the nerve environment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1543. doi:10.1158/1538-7445.AM2011-1543

Erratum: PEAZ-1: A new human prostate neoplastic epithelial cell line (Prostate (2001) 48 (79-92))

The original article to which this Erratum refers was published in The Prostate (2001) 48(79–92