Differences between males and females are normally attributed to developmental and hormonal differences between the sexes. Here, we demonstrate differences between males and females in gene silencing using a heterochromatin-sensitive reporter gene. Using "sex-reversal" mouse models with varying sex chromosome complements, we found that this differential gene silencing was determined by X chromosome complement, rather than sex. Genome-wide transcription profiling showed that the expression of hundreds of autosomal genes was also sensitive to sex chromosome complement. These genome-wide analyses also uncovered a role for Sry in modulating autosomal gene expression in a sex chromosome complement-specific manner. The identification of this additional layer in the establishment of sexual dimorphisms has implications for understanding sexual dimorphisms in physiology and disease.

The synucleins are a small, soluble, highly conserved group of neuronal proteins that have been implicated in both neurodegenerative diseases and cancer. The synuclein family consists of alpha-, beta-, and gamma-synucleins (gamma-syn). They are a natively unfolded group of proteins that share sequence homologies and structural properties. So far, the biological functions of the synucleins are still unclear, but their involvement in neurodegenerative diseases and cancer may provide insights into the pathological processes that result from these two groups of debilitating diseases, and present the possibility to use them as potential targets for early diagnosis and treatment. Recently, elevated levels of gamma-syn proteins have been detected in various types of cancer, especially in advanced stages of the disease. Furthermore, studies to date indicate that overexpression of gamma-syn compromises normal mitotic checkpoint controls, resulting in multinucleation as well as faster cell growth. Gamma-syn has also been shown to promote invasion and metastasis in in vitro assays as well as in animal models. Overexpression of gamma-syn also interferes with drug-induced apoptotic responses. These observations raise questions about the involvement of gamma-syn in the process of tumorigenesis and metastasis, and efforts have already been made to use gamma-syn as a marker for assessing breast cancer progression. This review will discuss the involvement of gamma-syn in cancer progression, metastasis and its potential as a marker.

Endometriosis is a debilitating disease in which apoptotic, genetic, immunological, angiogenic and environmental factors have been implicated. Endocrine-disrupting agents (e.g. dioxins) might be involved. Dioxins, via the arylhydrocarbon receptor (AhR), induce estrogen-metabolizing enzymes CYP1A1 and CYP1B1. Elevated expression of gamma-SYNUCLEIN (gamma-SYN) has been associated with hormone-related conditions. Tissue sets consisting of eutopic and ectopic (ovarian) endometrium from patients with stage 3 or 4 endometriosis were obtained. Following RNA extraction and reverse transcription, quantitative real-time reverse transcriptase-polymerase chain reaction was performed for anti-apoptotic B-cell leukaemia/lymphoma 2 (BCL-2), CYP1A1, CYP1B1, estrogen receptor (ER)alpha, ER beta and gamma-SYN. Immunohistochemical analyses for gamma-syn, ER alpha, ER beta and CYP1A1 were also conducted. A 3-9-fold increase in intra-individual expression of CYP1A1 in ectopic (ovarian) endometrium compared with eutopic tissue was observed; immunohistochemical analyses pointed to CYP1A1 being localized to the glandular epithelium. This intra-individual expression profile was not observed for CYP1B1 or BCL-2. However, a 5-53-fold intra-individual increase in gamma-SYN expression was also demonstrated in six of nine tissue sets (a further two showed an increase that was not considered significant) when comparing ectopic to eutopic endometrium; gamma-syn positivity was associated with endothelial cells. An elevation in ER beta was also noted when comparing ectopic to eutopic endometrium; with regard to ER alpha, this was inconsistent. These results suggest an up-regulation of dioxin-inducible CYP1A1 and gamma-SYN occurs in endometriosis. Whether gamma-syn may be a novel diagnostic marker for endometriosis remains to be ascertained.

Cancer stem cells may mediate therapy resistance and recurrence in various types of cancer, including glioblastoma. Cancer stemlike cells can be isolated from long-term cancer cell lines, including glioma lines. Using sphere formation as a model for cancer cell stemness in vitro, we derived sphere cultures from SMA-497, SMA-540, SMA-560, and GL-261 glioma cells. Gene expression and proteomics profiling demonstrated that sphere cultures uniformly showed an elevated expression of stemness-associated genes, notably including CD44. Differences in neural lineage marker expression between nonsphere and sphere cultures were heterogeneous except for a uniform reduction of β-III-tubulin in sphere cultures. All sphere cultures showed slower growth. Self-renewal capacity was influenced by medium conditions but not nonsphere versus sphere culture phenotype. Sphere cultures were more resistant to irradiation, whereas both nonsphere and sphere cultures were highly resistant to temozolomide. Nonsphere cells formed more aggressive tumors in syngeneic mice than sphere cells in all models except SMA-560. There were no major differences in vascularization or infiltration by T cells or microglia/macrophages between nonsphere and sphere cell-derived tumors implanted in syngeneic hosts. Together, these data indicate that mouse glioma cell lines may be induced in vitro to form spheres that acquire features of stemness, but they do not exhibit a uniform biologic phenotype, thereby challenging the view that they represent a superior model system.