Sine oculis homeobox homolog 1 (Six1) is an evolutionarily conserved transcription factor that acts as master regulator of development and is frequently dysregulated in various types of cancer. Six1 has been demonstrated to be upregulated in human osteosarcoma cell lines compared with osteoblastic cell lines. However, the association of Six1 expression with the progression and prognosis of oste...

Glioblastoma multiforme (GBM) is the deadliest and most common form of malignant primary brain tumor in humans. However, until now, little is known about the glioma genesis and progression at the molecular level. Here we report that overexpression of sine oculis homeobox homolog 1 (Six1), a developmental transcription factor implicated in tumor onset and progression, can significantly promote g...

In Hodgkin lymphoma (HL) we recently identified deregulated expression of homeobox genes MSX1 and OTX2 which are physiologically involved in development of the embryonal neural plate border region. Here, we examined in HL homeobox gene SIX1 an additional regulator of this embryonal region mediating differentiation of placodal precursors. SIX1 was aberrantly activated in 12 % of HL patient sampl...

We previously demonstrated that the overexpression of homeoprotein Six1 in hepatocellular carcinoma (HCC) patients is associated with venous infiltration, advanced pathologic tumor metastasis (pTNM) stage and poor overall survival rate (Ng et al. Br J Cancer 2006;95:1050-5). In this study, short hairpin RNA (shRNA) interference approach was used to suppress the expression of Six1 in a metastati...

Homeobox genes constitute a large family of transcription factors that are essential during normal development and are often dysregulated in cancer. However, the molecular mechanisms by which homeobox genes influence cancer remain largely unknown. Here we show that the tissue-restricted cyclin A1 is a transcriptional target of the Six1 homeoprotein. Both genes are expressed in the embryonic but...

Malignant proliferation is the fundamental trait of tumor cells. The initiation of DNA replication represents a key process for cell proliferation, and has a marked impact on tumorigenesis and progression. Here we report that Sine oculis homeobox homolog 1 (SIX1) functions as a master regulator in DNA replication of cervical cancer cells. The expression of SIX1 was induced by the E7 oncoprotein...

Quiescent satellite cells are myogenic progenitors that enable regeneration of skeletal muscle. One of the early events of satellite cell activation following myotrauma is the induction of the myogenic regulatory factor MyoD, which eventually induces terminal differentiation and muscle function gene expression. The purpose of this study was to elucidate the mechanism by which MyoD is induced du...

A 12 kDa cysteine-rich protein is secreted by Fusarium oxysporum f. sp. lycopersici during colonization of tomato xylem vessels. Peptide sequences obtained with mass spectrometry allowed identification of the coding sequence. The gene encodes a 32 kDa protein, designated Six1 for secreted in xylem 1. The central part of Six1 corresponds to the 12 kDa protein found in xylem sap of infected plant...

Epithelial-mesenchymal transition (EMT) plays a critical role in promoting tumor invasion and metastasis. However, the key cofactors that modulate the signal transduction to induce EMT have note been fully explored to date. The present study reports that sine oculis homeobox homolog 1 (SIX1) is able to promote EMT of cervical cancer by coordinating with transforming growth factor (TGF)β-SMAD si...

Six homeoproteins are expressed in several tissues, including muscle, during vertebrate embryogenesis, suggesting that they may be involved in diverse differentiation processes. To determine the functions of the Six1 gene during myogenesis, we constructed Six1-deficient mice by replacing its first exon with the lacZ gene. Mice lacking Six1 die at birth because of severe rib malformations and sh...