A. Rustighi | Università degli Studi di Trieste (original) (raw)
Papers by A. Rustighi
Cancer Cell, 2011
TP53 missense mutations dramatically influence tumor progression, however, their mechanism of act... more TP53 missense mutations dramatically influence tumor progression, however, their mechanism of action is still poorly understood. Here we demonstrate the fundamental role of the prolyl isomerase Pin1 in mutant p53 oncogenic functions. Pin1 enhances tumorigenesis in a Li-Fraumeni mouse model and cooperates with mutant p53 in Ras-dependent transformation. In breast cancer cells, Pin1 promotes mutant p53 dependent inhibition of the antimetastatic factor p63 and induction of a mutant p53 transcriptional program to increase aggressiveness. Furthermore, we identified a transcriptional signature associated with poor prognosis in breast cancer and, in a cohort of patients, Pin1 overexpression influenced the prognostic value of p53 mutation. These results define a Pin1/mutant p53 axis that conveys oncogenic signals to promote aggressiveness in human cancers.
Cancer research, 1998
The expression of nuclear proteins high mobility group (HMG) I and HMGY was investigated in intra... more The expression of nuclear proteins high mobility group (HMG) I and HMGY was investigated in intraepithelial and invasive lesions of the uterine cervix. Human carcinoma cell lines C-41, ME-180, and CaSki were used for testing protein expression in neoplastic cells from the cervix. Morphological grading of the dysplasias (CIN 1, CIN 2, and CIN 3) and invasive carcinomas from formalin-fixed paraffin-embedded samples parallels the degree of nuclear immunostaining obtained using a polyclonal antibody raised against the amino-terminal region of HMGI(Y) proteins. The immunostaining obtained with HMGI(Y) antibody was compared with that observed using the antibody Ki-67, and the results were similar. We suggest the use of HMGI(Y) antibody in clinical oncology as a useful marker of intraepithelial lesions and invasive carcinomas.
Nucleic Acids Research, 1998
High mobility group I proteins (HMGI, HMGY and HMGI-C) are a family of low molecular mass non-his... more High mobility group I proteins (HMGI, HMGY and HMGI-C) are a family of low molecular mass non-histone nuclear proteins which constitute an important component of the active chromatin structure. Two members of this family, HMGI and HMGY, have been demonstrated to contribute to the transcriptional regulation of several promoters by interacting with the DNA and with different transcription factors. On the contrary, very little is known about the third member, HMGI-C, which plays an important role during embryonic growth and in the process of cell transformation, its gene being rearranged in a large number of mesenchimal tumors. In this paper we show for the first time that HMGI-C is also able to function as architectural factor, enhancing the activity of a transcription factor, NF-κB, through the PRDII element of the β-interferon enhancer. Moreover we show that this enhancement is absolutely dependent on the binding of HMGI-C to its target sequence. The demonstration that HMGI-C is able to modulate transcription is thus an important initial step in the identification of genes regulated by this factor.
Journal of Biological Chemistry, 2010
Reversible proline-directed phosphorylation at Ser/Thr-Pro motifs has an essential role in myogen... more Reversible proline-directed phosphorylation at Ser/Thr-Pro motifs has an essential role in myogenesis, a multistep process strictly regulated by several signaling pathways that impinge on two families of myogenic effectors, the basic helix-loop-helix myogenic transcription factors and the MEF2 (myocyte enhancer factor 2) proteins. The question of how these signals are deciphered by the myogenic effectors remains largely unaddressed. In this study, we show that the peptidyl-prolyl isomerase Pin1, which catalyzes the isomerization of phosphorylated Ser/Thr-Pro peptide bonds to induce conformational changes of its target proteins, acts as an inhibitor of muscle differentiation because its knockdown in myoblasts promotes myotube formation. With the aim of clarifying the mechanism of Pin1 function in skeletal myogenesis, we investigated whether MEF2C, a critical regulator of the myogenic program that is the end point of several signaling pathways, might serve as a/the target for the inhibitory effects of Pin1 on muscle differentiation. We show that Pin1 interacts selectively with phosphorylated MEF2C in skeletal muscle cells, both in vitro and in vivo. The interaction with Pin1 requires two novel critical phospho-Ser/Thr-Pro motifs in MEF2C, Ser(98) and Ser(110), which are phosphorylated in vivo. Overexpression of Pin1 decreases MEF2C stability and activity and its ability to cooperate with MyoD to activate myogenic conversion. Collectively, these findings reveal a novel role for Pin1 as a regulator of muscle terminal differentiation and suggest that Pin1-mediated repression of MEF2C function could contribute to this function.
FEBS Letters, 2004
The structural characteristics of the three nuclear phosphoproteins of the high mobility group A ... more The structural characteristics of the three nuclear phosphoproteins of the high mobility group A family are outlined and related to their participation in chromatin structure alteration in many biological processes such as gene expression, neoplastic transformation, differentiation, and apoptosis. The elevated expression of these proteins in tumor cells and their post-translational modifications, such as phosphorylation, acetylation and methylation, are discussed and suggested as suitable targets for cancer chemotherapy.
Cancer Research, 2006
HMGA1 is an architectural transcription factor expressed at high levels in transformed cells and ... more HMGA1 is an architectural transcription factor expressed at high levels in transformed cells and tumors. Several lines of evidence indicate that HMGA1 up-regulation is involved in the malignant transformation of thyroid epithelial cells. However, the mechanisms underlying the effect of HMGA1 on thyroid cancer cell phenotype are not fully understood. We now show that in thyroid cancer cells, HMGA1 down-regulation by small interfering RNA and antisense techniques results in enhanced transcriptional activity of p53, TAp63A, TAp73A, and, consequently, increased apoptosis. Coimmunoprecipitation and pull-down experiments with deletion mutants showed that the COOH-terminal oligomerization domain of p53 family members is required for direct interaction with HMGA1. Moreover, inhibition of HMGA1 expression in thyroid cancer cells resulted in increased p53 oligomerization in response to the DNA-damaging agent doxorubicin. Finally, electrophoretic mobility shift assay experiments showed that the p53-HMGA1 interaction results in reduced DNA-binding activity. These results indicate a new function of HMGA1 in the regulation of p53 family members, thus providing new mechanistic insights in tumor progression. (Cancer Res 2006; 66(6): 2980-89) Note: A. Rustighi is currently at the Laboratorio Nazionale CIB,
Cancer Cell, 2011
TP53 missense mutations dramatically influence tumor progression, however, their mechanism of act... more TP53 missense mutations dramatically influence tumor progression, however, their mechanism of action is still poorly understood. Here we demonstrate the fundamental role of the prolyl isomerase Pin1 in mutant p53 oncogenic functions. Pin1 enhances tumorigenesis in a Li-Fraumeni mouse model and cooperates with mutant p53 in Ras-dependent transformation. In breast cancer cells, Pin1 promotes mutant p53 dependent inhibition of the antimetastatic factor p63 and induction of a mutant p53 transcriptional program to increase aggressiveness. Furthermore, we identified a transcriptional signature associated with poor prognosis in breast cancer and, in a cohort of patients, Pin1 overexpression influenced the prognostic value of p53 mutation. These results define a Pin1/mutant p53 axis that conveys oncogenic signals to promote aggressiveness in human cancers.
Biochemical and Biophysical Research Communications, 2003
HMGA2 2 belongs to the high mobility group A (HMGA) family of architectural transcription factors... more HMGA2 2 belongs to the high mobility group A (HMGA) family of architectural transcription factors which participate in a wide variety of nuclear processes ranging from transcription to recombination, playing an important role in chromatin remodelling. HMGA2 is expressed during embryogenesis but not by adult somatic tissues, yet it becomes re-expressed following neoplastic transformation. A role in development is underscored by the finding that the inactivation of the Hmga2 gene is responsible for the murine pygmy phenotype. To elucidate mechanisms that control HMGA2 expression, we have previously cloned the gene and identified functional elements involved in its regulation. In this paper, transgenic mice were generated to define genomic regions involved in Hmga2 developmental and tissue-specific transcriptional regulation. A genomic region from )8.1 to )3.7 kb upstream from the initiation site has been found to recapitulate most of the spatial and temporal endogenous Hmga2 gene expression.
Human Molecular Genetics, 2014
Ectrodactyly, or Split-Hand/Foot Malformation (SHFM), is a congenital condition characterized by ... more Ectrodactyly, or Split-Hand/Foot Malformation (SHFM), is a congenital condition characterized by the loss of central rays of hands and feet. The p63 and the DLX5;DLX6 transcription factors, expressed in the embryonic limb buds and ectoderm, are disease genes for these conditions. Mutations of p63 also cause the ectodermal dysplasia -ectrodactyly -cleft lip/palate (EEC) syndrome, comprising SHFM. Ectrodactyly is linked to defects of the apical ectodermal ridge (AER) of the developing limb buds. FGF8 is the key signaling molecule in this process, able to direct proximo-distal growth and patterning of the skeletal primordial of the limbs. In the limb buds of both p63 and Dlx5;Dlx6 murine models of SHFM, the AER is poorly stratified and FGF8 expression is severely reduced. We show here that the FGF8 locus is a downstream target of DLX5 and that FGF8 counteracts Pin1 -DNp63a interaction. In vivo, lack of Pin1 leads to accumulation of the p63 protein in the embryonic limbs and ectoderm. We show also that DNp63a protein stability is negatively regulated by the interaction with the prolyl-isomerase Pin1, via proteasome-mediated degradation; p63 mutant proteins associated with SHFM or EEC syndromes are resistant to Pin1 action. Thus, DLX5, p63, Pin1 and FGF8 participate to the same timeand location-restricted regulatory loop essential for AER stratification, hence for normal patterning and skeletal morphogenesis of the limb buds. These results shed new light on the molecular mechanisms at the basis of the SHFM and EEC limb malformations.
Cancer Cell, 2011
TP53 missense mutations dramatically influence tumor progression, however, their mechanism of act... more TP53 missense mutations dramatically influence tumor progression, however, their mechanism of action is still poorly understood. Here we demonstrate the fundamental role of the prolyl isomerase Pin1 in mutant p53 oncogenic functions. Pin1 enhances tumorigenesis in a Li-Fraumeni mouse model and cooperates with mutant p53 in Ras-dependent transformation. In breast cancer cells, Pin1 promotes mutant p53 dependent inhibition of the antimetastatic factor p63 and induction of a mutant p53 transcriptional program to increase aggressiveness. Furthermore, we identified a transcriptional signature associated with poor prognosis in breast cancer and, in a cohort of patients, Pin1 overexpression influenced the prognostic value of p53 mutation. These results define a Pin1/mutant p53 axis that conveys oncogenic signals to promote aggressiveness in human cancers.
Cancer research, 1998
The expression of nuclear proteins high mobility group (HMG) I and HMGY was investigated in intra... more The expression of nuclear proteins high mobility group (HMG) I and HMGY was investigated in intraepithelial and invasive lesions of the uterine cervix. Human carcinoma cell lines C-41, ME-180, and CaSki were used for testing protein expression in neoplastic cells from the cervix. Morphological grading of the dysplasias (CIN 1, CIN 2, and CIN 3) and invasive carcinomas from formalin-fixed paraffin-embedded samples parallels the degree of nuclear immunostaining obtained using a polyclonal antibody raised against the amino-terminal region of HMGI(Y) proteins. The immunostaining obtained with HMGI(Y) antibody was compared with that observed using the antibody Ki-67, and the results were similar. We suggest the use of HMGI(Y) antibody in clinical oncology as a useful marker of intraepithelial lesions and invasive carcinomas.
Nucleic Acids Research, 1998
High mobility group I proteins (HMGI, HMGY and HMGI-C) are a family of low molecular mass non-his... more High mobility group I proteins (HMGI, HMGY and HMGI-C) are a family of low molecular mass non-histone nuclear proteins which constitute an important component of the active chromatin structure. Two members of this family, HMGI and HMGY, have been demonstrated to contribute to the transcriptional regulation of several promoters by interacting with the DNA and with different transcription factors. On the contrary, very little is known about the third member, HMGI-C, which plays an important role during embryonic growth and in the process of cell transformation, its gene being rearranged in a large number of mesenchimal tumors. In this paper we show for the first time that HMGI-C is also able to function as architectural factor, enhancing the activity of a transcription factor, NF-κB, through the PRDII element of the β-interferon enhancer. Moreover we show that this enhancement is absolutely dependent on the binding of HMGI-C to its target sequence. The demonstration that HMGI-C is able to modulate transcription is thus an important initial step in the identification of genes regulated by this factor.
Journal of Biological Chemistry, 2010
Reversible proline-directed phosphorylation at Ser/Thr-Pro motifs has an essential role in myogen... more Reversible proline-directed phosphorylation at Ser/Thr-Pro motifs has an essential role in myogenesis, a multistep process strictly regulated by several signaling pathways that impinge on two families of myogenic effectors, the basic helix-loop-helix myogenic transcription factors and the MEF2 (myocyte enhancer factor 2) proteins. The question of how these signals are deciphered by the myogenic effectors remains largely unaddressed. In this study, we show that the peptidyl-prolyl isomerase Pin1, which catalyzes the isomerization of phosphorylated Ser/Thr-Pro peptide bonds to induce conformational changes of its target proteins, acts as an inhibitor of muscle differentiation because its knockdown in myoblasts promotes myotube formation. With the aim of clarifying the mechanism of Pin1 function in skeletal myogenesis, we investigated whether MEF2C, a critical regulator of the myogenic program that is the end point of several signaling pathways, might serve as a/the target for the inhibitory effects of Pin1 on muscle differentiation. We show that Pin1 interacts selectively with phosphorylated MEF2C in skeletal muscle cells, both in vitro and in vivo. The interaction with Pin1 requires two novel critical phospho-Ser/Thr-Pro motifs in MEF2C, Ser(98) and Ser(110), which are phosphorylated in vivo. Overexpression of Pin1 decreases MEF2C stability and activity and its ability to cooperate with MyoD to activate myogenic conversion. Collectively, these findings reveal a novel role for Pin1 as a regulator of muscle terminal differentiation and suggest that Pin1-mediated repression of MEF2C function could contribute to this function.
FEBS Letters, 2004
The structural characteristics of the three nuclear phosphoproteins of the high mobility group A ... more The structural characteristics of the three nuclear phosphoproteins of the high mobility group A family are outlined and related to their participation in chromatin structure alteration in many biological processes such as gene expression, neoplastic transformation, differentiation, and apoptosis. The elevated expression of these proteins in tumor cells and their post-translational modifications, such as phosphorylation, acetylation and methylation, are discussed and suggested as suitable targets for cancer chemotherapy.
Cancer Research, 2006
HMGA1 is an architectural transcription factor expressed at high levels in transformed cells and ... more HMGA1 is an architectural transcription factor expressed at high levels in transformed cells and tumors. Several lines of evidence indicate that HMGA1 up-regulation is involved in the malignant transformation of thyroid epithelial cells. However, the mechanisms underlying the effect of HMGA1 on thyroid cancer cell phenotype are not fully understood. We now show that in thyroid cancer cells, HMGA1 down-regulation by small interfering RNA and antisense techniques results in enhanced transcriptional activity of p53, TAp63A, TAp73A, and, consequently, increased apoptosis. Coimmunoprecipitation and pull-down experiments with deletion mutants showed that the COOH-terminal oligomerization domain of p53 family members is required for direct interaction with HMGA1. Moreover, inhibition of HMGA1 expression in thyroid cancer cells resulted in increased p53 oligomerization in response to the DNA-damaging agent doxorubicin. Finally, electrophoretic mobility shift assay experiments showed that the p53-HMGA1 interaction results in reduced DNA-binding activity. These results indicate a new function of HMGA1 in the regulation of p53 family members, thus providing new mechanistic insights in tumor progression. (Cancer Res 2006; 66(6): 2980-89) Note: A. Rustighi is currently at the Laboratorio Nazionale CIB,
Cancer Cell, 2011
TP53 missense mutations dramatically influence tumor progression, however, their mechanism of act... more TP53 missense mutations dramatically influence tumor progression, however, their mechanism of action is still poorly understood. Here we demonstrate the fundamental role of the prolyl isomerase Pin1 in mutant p53 oncogenic functions. Pin1 enhances tumorigenesis in a Li-Fraumeni mouse model and cooperates with mutant p53 in Ras-dependent transformation. In breast cancer cells, Pin1 promotes mutant p53 dependent inhibition of the antimetastatic factor p63 and induction of a mutant p53 transcriptional program to increase aggressiveness. Furthermore, we identified a transcriptional signature associated with poor prognosis in breast cancer and, in a cohort of patients, Pin1 overexpression influenced the prognostic value of p53 mutation. These results define a Pin1/mutant p53 axis that conveys oncogenic signals to promote aggressiveness in human cancers.
Biochemical and Biophysical Research Communications, 2003
HMGA2 2 belongs to the high mobility group A (HMGA) family of architectural transcription factors... more HMGA2 2 belongs to the high mobility group A (HMGA) family of architectural transcription factors which participate in a wide variety of nuclear processes ranging from transcription to recombination, playing an important role in chromatin remodelling. HMGA2 is expressed during embryogenesis but not by adult somatic tissues, yet it becomes re-expressed following neoplastic transformation. A role in development is underscored by the finding that the inactivation of the Hmga2 gene is responsible for the murine pygmy phenotype. To elucidate mechanisms that control HMGA2 expression, we have previously cloned the gene and identified functional elements involved in its regulation. In this paper, transgenic mice were generated to define genomic regions involved in Hmga2 developmental and tissue-specific transcriptional regulation. A genomic region from )8.1 to )3.7 kb upstream from the initiation site has been found to recapitulate most of the spatial and temporal endogenous Hmga2 gene expression.
Human Molecular Genetics, 2014
Ectrodactyly, or Split-Hand/Foot Malformation (SHFM), is a congenital condition characterized by ... more Ectrodactyly, or Split-Hand/Foot Malformation (SHFM), is a congenital condition characterized by the loss of central rays of hands and feet. The p63 and the DLX5;DLX6 transcription factors, expressed in the embryonic limb buds and ectoderm, are disease genes for these conditions. Mutations of p63 also cause the ectodermal dysplasia -ectrodactyly -cleft lip/palate (EEC) syndrome, comprising SHFM. Ectrodactyly is linked to defects of the apical ectodermal ridge (AER) of the developing limb buds. FGF8 is the key signaling molecule in this process, able to direct proximo-distal growth and patterning of the skeletal primordial of the limbs. In the limb buds of both p63 and Dlx5;Dlx6 murine models of SHFM, the AER is poorly stratified and FGF8 expression is severely reduced. We show here that the FGF8 locus is a downstream target of DLX5 and that FGF8 counteracts Pin1 -DNp63a interaction. In vivo, lack of Pin1 leads to accumulation of the p63 protein in the embryonic limbs and ectoderm. We show also that DNp63a protein stability is negatively regulated by the interaction with the prolyl-isomerase Pin1, via proteasome-mediated degradation; p63 mutant proteins associated with SHFM or EEC syndromes are resistant to Pin1 action. Thus, DLX5, p63, Pin1 and FGF8 participate to the same timeand location-restricted regulatory loop essential for AER stratification, hence for normal patterning and skeletal morphogenesis of the limb buds. These results shed new light on the molecular mechanisms at the basis of the SHFM and EEC limb malformations.