Proteomic analysis of dunning prostate cancer cell lines with variable metastatic potential using SELDI-TOF.

BACKGROUND: Surface enhanced laser desorption and ionization-time-of-flight (SELDI-TOF) is an evolving proteomic technology for improving biomarker discovery that allows for rapid and sensitive analysis of complex protein mixtures generated from body fluids, cells, and/or tissues. SELDI--based profiling identifies unique, differentially expressed proteins relating to specific cancer-related disease states. We utilized SELDI-TOF following pre-processing with molecular separation and chemical fractionation of cell membrane extracts from three Dunning rat prostate cancer cell lines of varying metastatic potential to search novel proteins that are differentially expressed. METHODS: Dunning rat cell sublines of variable (%) metastatic potential; G (0%), AT-1 (20%), and Mat-Ly-Lu (100%) were cultured in two different laboratories. Cell lysis was performed in a homogenation buffer (320 mM sucrose/50 mM Tris/0.5 mM PSMF) using Dounce homogenation. After centrifugation, the membrane pellet was washed 2x and then solublized in 2% CHAPS/8 M urea. This sample was further processed using positive pressure molecular ultrafiltration at 30 kDa or precipitation with 50% ammonium sulfate. Next, each sample was applied to an IMAC3-Ni ProteinChip (Ciphergen Biosystems, Freemont, CA) and analyzed using Ciphergen's Protein Biology System with protein peak analysis software. RESULTS: SELDI-TOF analysis differentiated the three Dunning rat cell sublines based upon protein concentration normalized profiles between 5,000 and 20,000 Da. The preparations from the three cells lines showed clear differences when the extracts from the metastatic sublines (AT-1 and MLL) were compared to the benign subline (G) for proteins with molecular weights of 9 kDa (decrease), 12 kDa (significant decrease), 14 kDa (decrease), and 17 kDa (significant gain). After pre-processing extracts with ammonium sulfate and molecular ultrafiltration, the molecular profile changes from one subline to the next became more apparent. Our results were reproducible using multiple runs including from Dunning cells cultured in a separate laboratory, and using different lots of SELDI ProteinChips. CONCLUSIONS: The application of SELDI-TOF to a series of Dunning rat prostate cancer cell lines illustrated apparent changes in protein profiles among the three cell lines with known differences in metastatic biologic activity. SELDI-TOF identified four reproducible changes in protein expression in the AT1 and MLL metastatic cell sublines. Three of the expression changes were manifested as decreases, but one protein (17 kDa) was over-expressed in the AT1 and MLL cell lines. Emphasis will be placed on the isolation, purification, and characterization of the 17 kDa over-expressed protein and its potential role in PCa metastasis.

Femme on the streets, butch in the sheets? Lesbian sex-roles, dyadic adjustment, and sexual satisfaction.

Recent research suggests that butch-femme role playing in lesbian couples has diminished and been replaced with androgynous attitudes and behaviors. Are lesbians, however, able to maintain an androgynous approach when it comes to lovemaking? Or does the bedroom give way to the powerful influence of traditional gender-based norms for sexual behavior? What implications does the choice of sex-roles have for relationship and sexual satisfaction in lesbian couples? The present study of 111 lesbians explores the relationship between sex-role self-perceptions, sexual satisfaction, and sexual fulfillment. Findings indicate that lesbians perceive themselves as significantly more feminine when they are interacting sexually than their overall or global sex-role perception. Furthermore, lesbians who view themselves as either androgynous or feminine in a sexual context had the highest level of sexual satisfaction and dyadic adjustment among all four sex-role groups.

Dyadic adjustment/sexual satisfaction in women and men as a function of psychological sex role self-perception.

Men and women who were found to be androgynous in the sexual situation were more sexually satisfied and had better adjustment in their dyadic relationship than their sex role stereotypic counterparts. This finding was not surprising, since androgyny implies more flexibility. On the other hand, the finding was surprising in light of the fact that large numbers of both men and women in the study sample perceived themselves as feminine in the sexual situation, compared to their global sex role self-perception. Several explanations are offered with respect to these outcomes, and the importance of qualitative differences between men and women is highlighted.