Cloning of the human RHOB gene promoter: characterization of a VNTR sequence that affects transcriptional activity

Tovar, Daniel; Faye, Jean-Charles; Favre, Gilles

doi:10.1016/s0888-7543(03)00044-2

Cited by 21 publications

(25 citation statements)

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“…However, we here show that a VNTR sequence carrying 13 repeats increases the transcriptional activity of RHOB compared to a VNTR with only 9 repeats. Our findings may seem contradictory to what has been published before (Tovar et al 2003): Tovar et al analyzed the effect of the VNTR sequence in combination with the SV40 promoter and did not find an impact of the number of repeats on the transcriptional activity. We here investigated the VNTR in combination with its native RHOB promoter and we used the chondrocyte-like RHOB encodes a small GTPase which is involved in a broad range of cellular processes like vesicular transport, actin organization and apoptosis (Prendergast 2001;Ridley 2001) and indeed, we recently described a significant increase of apoptosis in RHOB overexpressing chondrocyte-like SW1353 cells (Mahr et al, submitted manuscript).…”

Section: Discussioncontrasting

confidence: 99%

“…1a) (Tovar et al 2003). To test if OA patients and healthy controls differ in their VNTRs, we analyzed larger cohorts via PCR amplification.…”

Section: Cell Type-restricted Regulation Of the Vntr Polymorphismmentioning

confidence: 99%

“…actin organization, vesicular transport, stress response, and apoptosis (Prendergast 2001;Ridley 2001). Sequence analysis of the RHOB promoter region revealed the presence of additional polymorphisms including several SNPs (unpublished data) and a VNTR sequence (Tovar et al 2003). We here used Luciferase reporter assays to investigate RHOB promoter polymorphisms for their functional impact on transcriptional regulation.…”

Section: Introductionmentioning

confidence: 99%

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Transcriptional activity of the RHOB gene is influenced by regulatory polymorphisms in its promoter region

Mahr

Müller‐Hilke

2007

HUGO J

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Osteoarthritis (OA) is a chronic joint disease with genetic as well as environmental factors contributing to its etiology. We recently identified RHOB as a gene overexpressed in osteoarthritis. Interestingly, RHOB harbors numerous polymorphisms in its promoter region and genotyping of OA patients and healthy controls revealed an association of the single nucleotide polymorphism (SNP) rs585017 with the disease. We here set out to investigate the influence of RHOB promoter polymorphisms on the transcriptional activity of the gene and we found evidence that the SNPs rs2602160 and rs585017 cooperate in regulating RHOB expression. In addition, a variable number of tandem repeats (VNTR) impacts on the RHOB transcriptional activity in a cell type restricted manner. These results mechanistically link our previous finding of an elevated RHOB expression to the disease associated SNP rs585017 and confirm a role for regulatory polymorphisms in osteoarthritis.

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Section: Discussioncontrasting

confidence: 99%

“…1a) (Tovar et al 2003). To test if OA patients and healthy controls differ in their VNTRs, we analyzed larger cohorts via PCR amplification.…”

Section: Cell Type-restricted Regulation Of the Vntr Polymorphismmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Transcriptional activity of the RHOB gene is influenced by regulatory polymorphisms in its promoter region

Mahr

Müller‐Hilke

2007

HUGO J

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“…Fritz et al (12) confirmed that Rho proteins (RhoA, RhoB, and RhoC) are not altered by mutation in breast tumors. We reported recently the presence of a VNTR sequence in the human RhoB promoter that is known to be linked with the penetrance and the development of several cancers (37). An epigenetic regulation has also been proposed by Wang et al (38) by finding that RhoB induction is mediated by histone deacetylase inhibition.…”

Section: Discussionmentioning

confidence: 57%

Loss of RhoB Expression in Human Lung Cancer Progression

Mazières

Antonia

D'aste

et al. 2004

Clinical Cancer Research

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158

143

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Purpose: RhoB is a low molecular weight GTPase belonging to the Ras protein superfamily. Whereas most Rho proteins have been shown to have a positive role in proliferation and malignant transformation, the specific role of RhoB appears more divergent. We reported previously that RhoB inhibits cell proliferation in various human cancer cells. Here, we studied the specific role played by RhoB in human lung cancer.Experimental Design: We analyzed the expression of RhoB protein by immunostaining in human lung tissues ranging from normal to invasive carcinoma from different histological types in two large independent studies of, respectively, 94 and 45 samples. We then studied the cellular effect of RhoB overexpression in a model of lung cancer (A549, adenocarcinoma) and tumorigenicity in nude mice.Results: We showed in both studies that RhoB protein was expressed in normal lung and decreased dramatically through lung cancer progression (P < 0.01). Interestingly, RhoB expression was lost in 96% of invasive tumors and reduced by 86% in poorly differentiated tumors compared with the nonneoplastic epithelium. Moreover, the loss of expression of RhoB correlated significantly with tumor stage and proliferative index, whereas no correlation was found between RhoB and p53 or Bcl-2 expression. We then showed that ectopic expression of RhoB in lung cancer cell line A549 suppressed cell proliferation, anchorage-independent growth, and xenograft tumor growth in nude mice.Conclusions: RhoB loss of expression occurs very frequently in lung carcinogenesis, reinforcing its putative tumor suppressive activity, and raising the value of its potential use in cancer therapy.

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“…Study of RhoB Promoter Activity-The 1,876-bp MluI/XhoI fragment corresponding to RhoB promoter sequence was inserted into pGL3-Basic (Promega) upstream of the Firefly luciferase gene and co-transfected with a pRL-CMV vector (Promega) as an internal control (Renilla luciferase under the control of a cytomegalovirus (CMV) promoter) as described previously (31).…”

Section: Methodsmentioning

confidence: 99%

RhoB Protects Human Keratinocytes from UVB-induced Apoptosis through Epidermal Growth Factor Receptor Signaling

Canguilhem

Pradines

Baudouin

et al. 2005

Journal of Biological Chemistry

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Exposure of the skin to UVB light results in the formation of DNA photolesions that can give rise to cell death, mutations, and the onset of carcinogenic events. Specific proteins are activated by UVB and then trigger signal transduction pathways that lead to cellular responses. An alteration of these signaling molecules is thought to be a fundamental event in tumor promotion by UVB irradiation. RhoB, encoding a small GTPase has been identified as a DNA damage-inducible gene. RhoB is involved in epidermal growth factor (EGF) receptor trafficking, cytoskeletal organization, cell transformation, and survival. We have analyzed the regulation of RhoB and elucidated its role in the cellular response of HaCaT keratinocytes to relevant environmental UVB irradiation. We report here that the activated GTP-bound form of RhoB is increased rapidly within 5 min of exposure to UVB, and then RhoB protein levels increased concomitantly with EGF receptor (EGFR) activation. Inhibition of UVB-induced EGFR activation prevents RhoB protein expression and AKT phosphorylation but not the early activation of RhoB. Blocking UVB-induced RhoB expression with specific small interfering RNAs inhibits AKT and glycogen synthase kinase-3␤ phosphorylation through inhibition of EGFR expression. Moreover, down-regulation of RhoB potentiates UVB-induced cell apoptosis. In contrast, RhoB overexpression protects keratinocytes against UVB-induced apoptosis. These results indicated that RhoB is regulated upon UVB exposure by a two-step process consisting of an early EGFR-independent RhoB activation followed by an EGFR-dependent induction of RhoB expression. Moreover, we have demonstrated that RhoB is essential in regulating keratinocyte cell survival after UVB exposure, suggesting its potential role in photocarcinogenesis.Among solar UV radiation that reaches the surface of the earth, UVB wavelengths are the most energetic. Directly absorbed by DNA and proteins, they account for much of the damaging biological effects of UV irradiation including premature skin aging and cancer (1). UVB acts as a carcinogen through both DNA damage and epigenetic effects. The initiation process in UVB-induced skin carcinogenesis involves UV light-induced DNA damage such as p53 or HA-ras mutations and represents an irreversible process (reviewed in Ref. 2). By contrast, UVBmediated skin tumor promotion involves the clonal expansion of initiated cells through activation of numerous signal transduction pathways, such as the MAPK 2 signaling cascades that coordinate cell cycle arrest, regulation of DNA repair, and apoptosis (3).It appears evident that after UVB exposure, the cell needs to integrate two opposing responses, with the final fate of keratinocytes depending on the balance between pro-and anti-apoptotic pathways. On the one hand, eliminating cells with excessive DNA damage is essential to preserve the health of the skin. UV-induced apoptosis plays this role through a complex mechanism triggered in three independent ways, via DNA damage-induced activation of caspas...

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Cloning of the human RHOB gene promoter: characterization of a VNTR sequence that affects transcriptional activity

Cited by 21 publications

References 20 publications

Transcriptional activity of the RHOB gene is influenced by regulatory polymorphisms in its promoter region

Transcriptional activity of the RHOB gene is influenced by regulatory polymorphisms in its promoter region

Loss of RhoB Expression in Human Lung Cancer Progression

RhoB Protects Human Keratinocytes from UVB-induced Apoptosis through Epidermal Growth Factor Receptor Signaling

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