Nuclear SOX2 Research Articles

Expression of The Embryonic Stem Cell Transcription Factor SOX2 in Human Skin: Relevance to Melanocyte and Merkel Cell Biology

SOX2 is a gene located on chromosome 3q26.33 that encodes a transcription factor important to maintenance of embryonic neural crest stem cell pluripotency. We have identified rare SOX2-immunoreactive cells in normal human skin at or near the established stem cell niches. Three subsets of SOX2-positive cells were defined in these regions: those expressing only SOX2 and those that co-expressed SOX2 and either CK20 or microphthalmia-associated transcription factor, which are consistent with dichotomous differentiation of SOX2-expressing precursors along neuroendocrine (Merkel cell) or melanocytic lines, respectively. Examination of Merkel cell carcinomas confirmed nuclear SOX2 expression in this tumor type. In human patient melanoma, strong nuclear expression of SOX2 was noted in a subset of tumors, and the ability to detect SOX2 in lesional cells significantly correlated with primary tumor thickness in a survey cohort. To assess the potential role of SOX2 in melanoma growth, an in vivo tumorigenesis assay was used. Whereas SOX2 knockdown failed to influence proliferation of cultured melanoma cells in vitro, tumor xenografts generated with the SOX2-knockdown cell line showed significant decrease in mean tumor volume as compared with controls. In aggregate, these findings suggest that SOX2 is a novel biomarker for subpopulations of normal skin cells that reside in established stem cell niches and that might relate to Merkel cell and melanocyte ontogeny and tumorigenesis.

Nuclear expression of sox11 is highly associated with mantle cell lymphoma but is independent of t(11;14)(q13;q32) in non-mantle cell B-cell neoplasms

Sox11 is a transcription factor involved in embryonic neurogenesis and tissue remodeling. Its role in lymphopoiesis is presently unknown. Recent studies have shown the nuclear expression of sox11 in mantle cell lymphoma, which raises the question about its possible association with t(11;14)(q13;q32), the genetic hallmark of mantle cell lymphoma leading to the overexpression of cyclin D1. In this study, we examined sox11 expression in 211 cases of B-cell neoplasms by immunohistochemistry, and evaluated its association with t(11;14) and overexpression of cyclin D1. Nuclear staining of sox11 was observed in 54 of 57 (95%) mantle cell lymphomas, including 52 of 53 (98%) classical and 2 of 4 variant types. Two of the three mantle cell lymphomas negative for nuclear sox11 staining were analyzed and were positive for t(11;14). All other B-cell lymphomas (114 cases) showed variable positive staining in the cytoplasm, but no nuclear positivity. Sox11 was then examined in plasma cell myeloma and hairy cell leukemia as a subset of plasma cell myeloma carry t(11;14) and overexpress cyclin D1, and cyclin D1 is overexpressed in a subset of hairy cell leukemia independent of t(11;14). We found no nuclear staining of sox11 in 30 plasma cell myelomas examined, including 12 cases with t(11;14)(q13;q32). It is interesting that intense nuclear staining of sox11 was present in a subset of hairy cell leukemias (5 of 10), and was associated with the overexpression of cyclin D1. Our results indicate that the nuclear expression of sox11 is highly associated with mantle cell lymphoma, but is independent of t(11;14)(q13;q32) in non-mantle cell B-cell neoplasms. Its association with the overexpression of cyclin D1 in hairy cell leukemia suggests that sox11 may be involved in the upregulation of cyclin D1 in this leukemia.

Analysis of SOX2 expression in developing human testis and germ cell neoplasia.

The transcriptional regulators of pluripotency, POU5F1 (OCT4), NANOG and SOX2, are highly expressed in embryonal carcinoma (EC). In contrast to OCT4 and NANOG, SOX2 has not been demonstrated in the early human germ cell lineage or carcinoma in situ (CIS), the precursor for testicular germ cell tumours (TGCTs). Here, we have analysed SOX2 expression in CIS and overt TGCTs, as well as normal second and third trimester fetal, prepubertal and adult testes by in situ hybridisation and immunohistochemistry using three different antibodies. In contrast to earlier studies, we detected SOX2 mRNA in most CIS cells. We also detected speckled nuclear SOX2 immunoreactivity in CIS cells with one primary antibody, which was not apparent with other primary antibodies. The results demonstrate SOX2 gene expression in CIS for the first time and raise the possibility of post-transcriptional regulation, most likely sumoylation as a mechanism for limiting SOX2 action in these cells.

Nuclear Expression of the Sox 11 Transcription Factor in Mantle Cell Lymphoma, and Cytoplasmic Expression in Follicular Lymphoma and Multiple Myeloma: Pathogenetic Implications.

Abstract 2925Poster Board II-901Mantle cell lymphoma (MCL) is characterized by nuclear cyclin D1 expression resulting from the t(11;14)(q13;q32). As cyclin D1 overexpression alone is insufficient for B-cell transformation, we have investigated other potentially contributing mutations. Sox11 is a member of a large family of transcription factors containing a DNA-binding high-mobility group (HMG) domain and shares homology with Sox4, which is involved in lymphopoiesis. Recent reports have identified Sox11 expression in the majority of MCL, suggesting it may contribute to pathogenesis (Ek et al, Blood 2008;111:800; Wang et al, Br J Haematol 2008;143:248). Methods:Patients with MCL diagnosed at the Univ. of Virginia from 1997-2008 and for whom nodal, marrow or spleen tissue blocks were available were identified from the Pathology database. Follicular lymphoma (FL), marginal zone lymphoma (MZL), small lymphocytic lymphoma (SLL), hairy cell leukemia (HCL) and multiple myeloma (MM) were also analyzed. Formalin-fixed, paraffin-embedded samples were stained by immunohistochemistry for cyclinD1, Sox11 (rabbit a/Sox11, 1:100, Sigma) and Ki-67. Nuclear and/or cytoplasmic expression was determined by two of us (YT, JC). Results:All MCL samples revealed nuclear cyclin D1 expression. Nuclear but not cytoplasmic Sox11 expression was identified in all 24 non-blastoid and in 5/6 blastoid samples; 1 blastoid sample showed only cytoplasmic Sox11 staining (Table). Four of 5 HCL expressed cyclin D1 but were negative for Sox11; 4/5 MM also were cyclin D1-positive, with 3 positive for cytoplasmic Sox11 including 2 of the cyclin D1-positive cases. All 5 FL showed cytoplasmic Sox11 positivity, whereas all MZL and SLL were negative for cytoplasmic or nuclear staining.TypePatientsSamplesNuclear Cyclin D1+Nuclear Sox11+Cytoplasmic Sox11+MCL, non –blastoid222424240MCL, blastoid56651FL55N.D.105MZL66000SLL66000HCL255400MM3554031N.D. = Not Done23 spleen, 2 bone marrow samples3Bone marrow samples Conclusions:Nuclear Sox11 expression was uniformly identified in MCL, with the exception of cytoplasmic expression in a single blastoid case. No nuclear Sox11 was present in HCL or MM despite the expression of cyclin D1, although 3 MM showed cytoplasmic Sox11 staining. These findings suggest that nuclear Sox11 overexpression is not a direct result of dysregulated cyclin D1 signaling but instead occurs by alternative mechanisms. The significance of cytoplasmic staining remains uncertain. A potential pathogenetic role for Sox11 and possibly other Sox family transcription factors warrants further investigation in MCL and other lymphoproliferative neoplasms for diagnostic use and therapeutic targeting. Disclosures:No relevant conflicts of interest to declare.

Strong lymphoid nuclear expression of SOX11 transcription factor defines lymphoblastic neoplasms, mantle cell lymphoma and Burkitt's lymphoma

We surveyed lymphomas to determine the range of expression of the mantle cell lymphoma-associated SOX11 transcription factor and its relation to cyclin D1. On hundred and seventy-two specimens were immunostained for the SOX11 N and C termini. Cyclin D1 was detected by immunohistochemistry and quantitative reverse transcriptase polymerase chain reaction; in situ hybridization for t(11;14) was applied when needed. Nuclear SOX11 was strongly expressed in most B and T-lymphoblastic leukemia/lymphomas and half of childhood Burkitt's lymphomas, but only weakly expressed in some hairy cell leukemias. Chronic lymphocytic leukemia/lymphoma, marginal zone, follicular and diffuse large B-cell lymphomas were negative for SOX11, as were all cases of intermediate Burkitt's lymphomas/diffuse large B-cell lymphoma, myeloma, Hodgkin's lymphomas and mature T-cell and NK/T-cell lymphomas. In addition to mantle cell lymphoma, SOX11 is strongly expressed only in lymphoblastic malignancies and Burkitt's lymphomas. Its expression is independent of cyclin D1 (except for weak expression in hairy cell leukemias) and unlikely to be due to translocations in lymphoid neoplasia.

The subcellular Sox11 distribution pattern identifies subsets of mantle cell lymphoma: correlation to overall survival

Gene expression analysis demonstrated high expression of the neuronal transcription factor SOX11 in mantle cell lymphoma (MCL). In contrast to follicular lymphoma, small lymphocytic lymphoma and reactive lymphoid tissue, most MCLs tested (48/53 patients) expressed sox11 protein in the nucleus. Therefore nuclear sox11 expression represents a new tumour marker for a subset of MCL. However, 5/53 MCL cases expressed sox11 only in the cytoplasm; these MCL patients had a shorter survival compared to MCL with nuclear sox11 expression. These results suggest sox11 expression as a new diagnostic marker in MCL that could be related to the clinical and biological behaviour of MCL.