Misexpression of wild-type and truncated isoforms of the high-mobility group I proteins HMGI-C and HMGI(Y) in uterine leiomyomas

Novel Approaches to Possible Targeted Therapies and Prophylaxis of Uterine Fibroids

Uterine leiomyomas are the most common benign tumors in women of childbearing age. They may lead to problems of conception or complications during the gestational period. The methods of treatment include surgical (myomectomy and hysterectomy, embolization of arteries) and therapeutic treatment (ulipristal acetate, leuprolide acetate, cetrorelix, goserelin, mifepristone). Both approaches are efficient but incompatible with pregnancy planning. Therefore, there is a call for medical practice to develop therapeutical means of preventing leiomyoma onset in patients planning on becoming pregnant. Based on the analysis of GWAS data on the search for mononucleotide polymorphisms associated with the risk of leiomyoma, in meta-transcriptomic and meta-methylomic studies, target proteins have been proposed. Prospective therapeutic treatments of leiomyoma may be based on chemical compounds, humanized recombinant antibodies, vaccines based on markers of the uterine leiomyoma cells that are absent in the adult organism, or DNA and RNA preparations. Three different nosological forms of the disease associated with driver mutations in the MED12, HMGA2, and FH genes should be considered when developing or prescribing drugs. For example, synthetic inhibitors and vaccines based on matrix metalloproteinases MMP11 and MMP16 are expected to be effective only for the prevention of the occurrence of MED12-dependent nodules.

Proteomic Profiling Identifies Co-Regulated Expression of Splicing Factors as a Characteristic Feature of Intravenous Leiomyomatosis

Intravenous leiomyomatosis (IVLM) is a rare benign smooth muscle tumour that is characterised by intravenous growth in the uterine and pelvic veins. Previous DNA copy number and transcriptomic studies have shown that IVLM harbors unique genomic and transcriptomic alterations when compared to uterine leiomyoma (uLM), which may account for their distinct clinical behaviour. Here we undertake the first comparative proteomic analysis of IVLM and other smooth muscle tumours (comprising uLM, soft tissue leiomyoma and benign metastasizing leiomyoma) utilising data-independent acquisition mass spectrometry. We show that, at the protein level, IVLM is defined by the unique co-regulated expression of splicing factors. In particular, IVLM is enriched in two clusters composed of co-regulated proteins from the hnRNP, LSm, SR and Sm classes of the spliceosome complex. One of these clusters (Cluster 3) is associated with key biological processes including nascent protein translocation and cell signalling by small GTPases. Taken together, our study provides evidence of co-regulated expression of splicing factors in IVLM compared to other smooth muscle tumours, which suggests a possible role for alternative splicing in the pathogenesis of IVLM.

Ginsenoside Rb1 inhibits proliferation and promotes apoptosis by regulating HMGB1 in uterine fibroid cells

To study the effects of ginsenoside Rb1 and the molecular mechanisms on proliferation and apoptosis of uterine fibroid cells, Rb1 + pc DNA3.1, Rb1 + pc DNA3.1-HMGB1, si-NC or si-HMGB1 was transfected into uterine fibroid cells by liposome method; the inhibitory rate and proliferation of human uterine fibroid cells were detected by MTT assay; apoptosis of uterine fibroid cells was detected by flow cytometry assay; HMGB1 protein expression in uterine fibroid cells was detected by Western blot assay. Compared with untreated uterine fibroid cells, the inhibitory and apoptosis rate of uterine fibroid cells treated with Rb1 were significantly up-regulated, while the expression level of HMGB1 was significantly down-regulated (p < .05). HMGB1 knockdown inhibited proliferation and promoted apoptosis of uterine fibroid cells. HMGB1 overexpression reversed the inhibitory effect on proliferation and the promotion effect on apoptosis of Rb1 in uterine fibroid cells. Ginsenoside Rb1 could inhibit uterine fibroid cells proliferation and promote apoptosis. This mechanism might be directly related to the downregulation of HMGB1, providing a basis for the treatment of uterine fibroids with ginsenoside Rb1.

Screening of potential biomarkers in uterine leiomyomas disease via gene expression profiling analysis

The present study aimed to screen potential biomarkers for uterine leiomyomas disease, particularly target genes associated with the mediator of RNA polymerase II transcription subunit 12 (MED12) mutation. The microarray data of GSE30673, including 10 MED12 wild-type myometrium, 8 MED12 mutation leiomyoma and 2 MED12 wild-type leiomyoma samples, were downloaded from the Gene Expression Omnibus database. Compared with myometrium samples, differently-expressed genes (DEGs) in the MED12 mutation and wild-type leiomyoma samples were identified using the Limma package. The two sets of DEGs obtained were intersected to screen common DEGs. The DEGs in the MED12 mutation and wild-type leiomyoma samples, and common DEGs were defined as group A, B and C. Gene Ontology (GO) and pathway enrichment analyses were performed using the Database for Annotation, Visualization and Integrated Discovery online tool. Based on the Kyoto Encyclopedia of Genes and Genomes database, pathway relation networks were constructed. DEGs in GO terms and pathways were intersected to screen important DEGs. Subsequently, a gene co-expression network was constructed and visualized using Cytoscape software. Reverse transcription-quantitative polymerase chain reaction was used to detect the expression levels of important DEGs. A total of 1,258 DEGs in group A were screened, and enriched for extracellular matrix (ECM) organization and ECM-receptor interaction. In addition, a total of 1,571 DEGs in group B were enriched for cell adhesion. Furthermore, 391 DEGs were involved in extracellular matrix organization. Pathway relation networks of group A, B and C were constructed with nodes of 48, 39, and 28, respectively. Finally, 135 important DEGs were obtained, including Acyl-CoA synthetase medium-chain family member 3, protein S (α) (PROS1) and F11 receptor. A gene co-expression network with 68 nodes was constructed. The expression of caspase 1 (CASP1) and aldehyde dehydrogenase 1 family member A1 (ALDH1A1) was significant higher in SK-UT-1 compared with that in PHM1-31 cells, while the expression of PROS1 was significant lower in SK-UT-1 cells. These results that CASP1, ALDH1A1 and PROS1 may be potential biomarkers for uterine leiomyomas. Furthermore, hematopoietic prostaglandin D synthase and carbonyl reductase 3 (CBR3) may be particular genes associated with the MED12 mutation in this disease.

Intravenous leiomyomatosis: an unusual intermediate between benign and malignant uterine smooth muscle tumors

Intravenous leiomyomatosis is an unusual smooth muscle neoplasm with quasi-malignant intravascular growth but a histologically banal appearance. Herein, we report expression and molecular cytogenetic analyses of a series of 12 intravenous leiomyomatosis cases to better understand the pathogenesis of intravenous leiomyomatosis. All cases were analyzed for the expression of HMGA2, MDM2, and CDK4 proteins by immunohistochemistry based on our previous finding of der(14)t(12;14)(q14.3;q24) in intravenous leiomyomatosis. Seven of 12 (58%) intravenous leiomyomatosis cases expressed HMGA2, and none expressed MDM2 or CDK4. Colocalization of hybridization signals for probes from the HMGA2 locus (12q14.3) and from 14q24 by interphase fluorescence in situ hybridization (FISH) was detected in a mean of 89.2% of nuclei in HMGA2-positive cases by immunohistochemistry, but in only 12.4% of nuclei in negative cases, indicating an association of HMGA2 expression and this chromosomal rearrangement (P=8.24 × 10(-10)). Four HMGA2-positive cases had greater than two HMGA2 hybridization signals per cell. No cases showed loss of a hybridization signal by interphase FISH for the frequently deleted region of 7q22 in uterine leiomyomata. One intravenous leiomyomatosis case analyzed by array comparative genomic hybridization revealed complex copy number variations. Finally, expression profiling was performed on three intravenous leiomyomatosis cases. Interestingly, hierarchical cluster analysis of the expression profiles revealed segregation of the intravenous leiomyomatosis cases with leiomyosarcoma rather than with myometrium, uterine leiomyoma of the usual histological type, or plexiform leiomyoma. These findings suggest that intravenous leiomyomatosis cases share some molecular cytogenetic characteristics with uterine leiomyoma, and expression profiles similar to that of leiomyosarcoma cases, further supporting their intermediate, quasi-malignant behavior.

MicroRNAs in the development and pathobiology of uterine leiomyomata: does evidence support future strategies for clinical intervention?

BACKGROUND

Human leiomyomata (fibroids) are benign tumors of the uterus, represent the most common neoplasms of reproductive-aged women and have a prevalence of ∼70% in the general population. This disorder conveys a significant degree of morbidity and remains the leading indication for hysterectomy in the USA. Prior investigations of aberrant microRNA (miRNA) expression in various malignancies have provided invaluable insight into the role of this class of small non-coding RNAs in tumor growth. Evidence of irregular miRNA expression in uterine fibroids has garnered recent interest for diagnostic and therapeutic applications. Since miRNA gene targets modulate several processes implicated in the genesis of uterine fibroids, more focused investigation has the potential to elucidate the functional significance of miRNA in the genesis and pathology of the disease.

METHODS

Comprehensive electronic searches of peer reviewed published literature in PubMed (US National Library of Medicine, National Institute of Health; http://www.ncbi.nlm.nih.gov/pubmed/) were performed for content related to the biologic functions of miRNA, the roles of miRNA in human disease and studies investigating miRNA in the context of uterine leiomyomata. Herein, this article will review the current evidence supporting the use of miRNA expression profiling as an investigative tool to assess the pathobiology of uterine fibroids and will discuss potential future applications of miRNAs as biomarkers and therapeutic targets.

RESULTS

Mounting evidence supports a functional role for miRNA as either indirect or direct regulators of gene expression which impacts the pathobiology of uterine fibroids. Specifically, miRNAs let-7, 200a, 200c, 93, 106b and 21 have been implicated in cellular proliferation, apoptosis, extracellular matrix turnover, angiogenesis and inflammation. Preliminary data provide evidence to suggest that respective in vitro miRNA expression in leiomyomata and myometrium is regulated by sex steroids.

CONCLUSIONS

Collectively, the identification of aberrantly expressed miRNAs in uterine leiomyomata and accumulating data derived from mining of gene target prediction models and recent functional studies support the concept that miRNAs might impact the genesis and progression of disease. However, the specific biologic functions of differential miRNA expression have yet to be confirmed in vivo. Further functional studies and developing miRNA technology may provide the basis for future applications of miRNAs in clinical medicine as biomarkers and therapeutic targets.

DNA bending by the mammalian high-mobility group protein AT hook 2

The mammalian high-mobility group protein AT hook 2 (HMGA2) is a DNA binding protein that specifically recognizes the minor groove of AT-rich DNA sequences. Disruption of its expression pattern is directly linked to oncogenesis and obesity. In this paper, we constructed a new plasmid pBendAT to study HMGA2-induced DNA bending. pBendAT carries a 230 bp DNA segment containing five pairs of restriction enzyme sites, which can be used to produce a set of DNA fragments of identical length to study protein-induced DNA bending. The DNA fragments of identical length can also be generated using PCR amplification. Since pBendAT does not contain more than three consecutive AT base pairs, it is suitable for the assessment of DNA bending induced by proteins recognizing AT-rich DNA sequences. Indeed, using pBendAT, we demonstrated that HMGA2 is a DNA bending protein and bends all three tested DNA binding sequences of HMGA2, SELEX1, SELEX2, and PRDII. The DNA bending angles were estimated to be 34.2 degrees , 33.5 degrees , and 35.4 degrees , respectively.

Loss of let-7 binding sites resulting from truncations of the 3' untranslated region of HMGA2 mRNA in uterine leiomyomas

A subset of uterine leiomyomas (UL) shows chromosomal rearrangements of the region 12q14 approximately q15, leading to an overexpression of the high-mobility group protein A2 gene (HMGA2). Recent studies identified microRNAs of the let-7 family as post-transcriptional regulators of HMGA2. Intragenic chromosomal breakpoints might cause truncated HMGA2 transcripts lacking part of the 3' UTR. The corresponding loss of let-7 complementary sites (LCS) located in the 3' UTR would therefore stabilize HMGA2 mRNA. The aim of this study was to check UL with rearrangements of the chromosomal region 12q14 approximately 15 for truncated HMGA2 transcripts by real-time reverse-transcription polymerase chain reaction. In 8/13 leiomyomas with aberrations of chromosomal region 12q15, the results showed the presence of the complete 3' UTR with all LCS. A differential expression with highly reduced 3' untranslated region levels was found in 5/13 myomas. In two of these, full-length transcripts were almost undetectable. Truncated transcripts were apparently predominant in roughly one-third of UL with chromosomal rearrangements affecting the HMGA2 locus, where they lead to a higher stability of its transcripts and subsequently contribute to the overexpression of the protein. The assay used is also generally suited to detect submicroscopic alterations leading to truncated transcripts of HMGA2.

Binding the mammalian high mobility group protein AT-hook 2 to AT-rich deoxyoligonucleotides: enthalpy-entropy compensation

HMGA2 is a DNA minor-groove binding protein. We previously demonstrated that HMGA2 binds to AT-rich DNA with very high binding affinity where the binding of HMGA2 to poly(dA-dT)(2) is enthalpy-driven and to poly(dA)poly(dT) is entropy-driven. This is a typical example of enthalpy-entropy compensation. To further study enthalpy-entropy compensation of HMGA2, we used isothermal-titration-calorimetry to examine the interactions of HMGA2 with two AT-rich DNA hairpins: 5'-CCAAAAAAAAAAAAAAAGCCCCCGCTTTTTTTTTTTTTTTGG-3' (FL-AT-1) and 5'-CCATATATATATATATAGCCCCCGCTATATATATATATATGG-3' (FL-AT-2). Surprisingly, we observed an atypical isothermal-titration-calorimetry-binding curve at low-salt aqueous solutions whereby the apparent binding-enthalpy decreased dramatically as the titration approached the end. This unusual behavior can be attributed to the DNA-annealing coupled to the ligand DNA-binding and is eliminated by increasing the salt concentration to approximately 200 mM. At this condition, HMGA2 binding to FL-AT-1 is entropy-driven and to FL-AT-2 is enthalpy-driven. Interestingly, the DNA-binding free energies for HMGA2 binding to both hairpins are almost temperature independent; however, the enthalpy-entropy changes are dependent on temperature, which is another aspect of enthalpy-entropy compensation. The heat capacity change for HMGA2 binding to FL-AT-1 and FL-AT-2 are almost identical, indicating that the solvent displacement and charge-charge interaction in the coupled folding/binding processes for both binding reactions are similar.

Uterine artery occlusion for the treatment of symptomatic fibroids: Endoscopic, radiological and vaginal approach

Uterine fibroids are the most common solid pelvic tumors in women. Although many fibroids seem to cause no symptoms, for some women they can have serious adverse effects and impact on quality of life. Common symptoms associated with fibroids include abnormal uterine bleeding, pelvic pressure and reproductive dysfunction. The past decade has witnessed highly sophisticated diagnostic and therapeutic technology for fibroids. The tools currently at our disposal permit greater management flexibility, which must be tailored to the individual clinical situation. Nonsurgical treatments include medical therapy and treatments interfering with the blood supply to the uterus or the fibroid; among the latest introduced are uterine artery embolization performed by the interventional radiologist and laparoscopic uterine occlusion performed by the gynaecologist. Even simpler is the non-incision temporary uterine clamp directed with Doppler and placed in the side fornices in the vagina.

Expression levels of HMGA2 in adipocytic tumors correlate with morphologic and cytogenetic subgroups

Background

The HMGA2 gene encodes a protein that alters chromatin structure. Deregulation, typically through chromosomal rearrangements, of HMGA2 has an important role in the development of several mesenchymal neoplasms. These rearrangements result in the expression of a truncated protein lacking the acidic C-terminus, a fusion protein consisting of the AT-hook domains encoded by exons 1–3 and parts from another gene, or a full-length protein; loss of binding sites for regulatory microRNA molecules from the 3' untranslated region (UTR) of HMGA2 has been suggested to be a common denominator.

Methods

Seventy adipocytic tumors, representing different morphologic and cytogenetic subgroups, were analyzed by qRT-PCR to study the expression status of HMGA2; 18 of these tumors were further examined by PCR to search for mutations or deletions in the 3'UTR.

Results

Type (full-length or truncated) and level of expression varied with morphology and karyotype, with the highest levels in atypical lipomatous tumors and lipomas with rearrangements of 12q13-15 and the lowest in lipomas with 6p- or 13q-rearrangements, hibernomas, spindle cell lipomas and myxoid liposarcomas. All 18 examined tumors showed reduced or absent expression of the entire, or parts of, the 3'UTR, which was not due to mutations at the DNA level.

Conclusion

In adipocytic tumors with deregulated HMGA2 expression, the 3'UTR is consistently lost, either due to physical disruption of HMGA2 or a shift to production of shorter 3'UTR.

Uterine leiomyomata and decreased height: a common HMGA2 predisposition allele

Uterine leiomyomata (UL) are the most common female pelvic tumors and the primary indication for hysterectomy in the United States. We assessed genetic liability for UL by a known embryonic proliferation modulator, HMGA2, in 248 families ascertained through medical record-confirmed affected sister-pairs. Using a (TC)( n ) repeat in the 5' UTR and 17 SNPs spanning HMGA2, permutation-based association tests identified a significant increase in transmission of a single TC repeat allele (TC227) with UL (allele-specific P = 0.00005, multiple testing corrected min-P = 0.0049). The hypothesis that TC227 is a pathogenic variant is supported by a trend towards higher HMGA2 expression in TC227 allele-positive compared with non-TC227 UL tissue as well as by absence of culpable exonic sequence variants. HMGA2 has also been suggested recently by three genome-wide SNP studies to influence human height variation, and our examination of the affected sister-pair families revealed a significant association of TC227 with decreased height (allele-specific P = 0.00033, multiple testing corrected min-P = 0.016). Diminished stature and elevated risk of UL development have both been correlated with an earlier age of menarche, which may be the biological mechanism for TC227 effects as a tendency of women with TC227 to have an earlier onset of menarche was identified in our study population. These results indicate HMGA2 has a role in two growth-related phenotypes, UL predisposition and height, of which the former may affect future medical management decisions for many women.

Molecular and cytogenetic characterization of plexiform leiomyomata provide further evidence for genetic heterogeneity underlying uterine fibroids

The plexiform variant of uterine leiomyomata (UL) is named for its ribbons or nests of smooth muscle cells that have a rounded, epithelioid shape caused by their entrapment in abundant extracellular matrix. Plexiform UL are currently classified as epithelioid smooth muscle tumors alongside the less predictable, "true" epithelioid tumors (ie, leiomyoblastomas). Karyotypes of six plexiform UL cases were studied, and their abnormalities were found to differ from those of leiomyoblastomas. Analyses using real-time polymerase chain reaction, immunohistochemistry, and fluorescence in situ hybridization demonstrated elevated mRNA and protein levels of the architectural factor HMGA2 and, in some cases, increased DNA copy number. Four of these plexiform UL were profiled with Affymetrix human U133 plus 2.0 expression arrays. Cluster analysis using genes previously shown to discriminate benign and malignant uterine smooth muscle tissues revealed that the plexiform tumors form an isolated group in the benign branch. This is in contrast to an earlier finding in which another variant, cellular UL characterized by loss of a portion of the short arm of chromosome 1, clustered with malignant leiomyosarcomas. These results provide additional evidence of genetic heterogeneity underlying UL of various histological types. We further suggest that plexiform UL should be classified among tumors with extensive hyalinization rather than with "true" epithelioid smooth muscle neoplasms.

Specific recognition of AT-rich DNA sequences by the mammalian high mobility group protein AT-hook 2: a SELEX study

The mammalian high mobility group protein AT-hook 2 (HMGA2) is a transcriptional factor involved in cell differentiation and transformation. Disruption of its normal expression pattern is directly linked to oncogenesis and obesity. HMGA2 contains three "AT-hook" DNA binding domains, which specifically bind to the minor groove of AT-rich sequences. Using a PCR-based systematic evolution of ligands by exponential enrichment (SELEX) procedure, we have identified two consensus sequences for HMGA2, 5'-ATATTCGCGAWWATT-3' and 5'-ATATTGCGCAWWATT-3', where W represents A or T. These two consensus sequences have a unique and interesting feature: the first five base pairs are AT-rich, the middle four base pairs are GC-rich, and the last six base pairs are AT-rich. Our results showed that all three of these segments are critical for high-affinity binding of HMGA2 to DNA. For example, if one of the AT-rich sequences is mutated to a non-AT-rich sequence, the DNA binding affinity of HMGA2 is reduced at least 100-fold. Intriguingly, if the GC-segment is replaced by an AT-rich segment, the binding affinity of HMGA2 is reduced approximately 5-fold. Identification of the consensus sequences for HMGA2 represents an important step toward finding its binding sites within the genome.

A micro-RNA signature associated with race, tumor size, and target gene activity in human uterine leiomyomas

Human uterine leiomyomas (ULMs) are the most common neoplasms of women. Many genes are dysregulated in ULMs and some of this dysregulation may be due to abnormal expression of micro-RNAs (miRNAs). In this study, 55 ULMs and matched myometrium were collected from 41 patients for microarray-based global miRNA expression analysis. Of 206 miRNAs examined, 45 miRNAs were significantly up- or down-regulated in ULMs in comparison to the matched myometrium (P < 0.001). The top five dysregulated miRNAs in ULMs are the let-7 family, miR-21, miR-23b, miR-29b, and miR-197. Four polycistronic clusters of miRNAs were either up- or down-regulated, but not in a mixed pattern, indicative of coordinated regulation of these miRNAs. Significance analysis revealed that subsets of miRNAs were strongly associated with tumor sizes and race. By prediction analysis we identified some important tumorigenic genes previously identified in ULMs that may be targeted by the dysregulated miRNAs. HMGA2 was identified as one of target genes of the let-7 family of miRNAs and has been found to be suppressed by let-7 in vitro. This article contains Supplementary material available at http://www.interscience.wiley.com/jpages/1045-2257/suppmat.

Identification and characterization of novel human transcripts embedded within HMGA2 in t(12;14)(q15;q24.1) uterine leiomyoma

The high mobility group A2 protein (HMGA2) has been implicated in the pathogenesis of mesenchymal tumors such as leiomyoma, lipoma and hamartoma. HMGA2 was pinpointed by mapping the breakpoints in the chromosomal translocations in 12q15, especially the t(12;14) that is commonly seen in uterine leiomyoma. It is generally assumed that altered expression of HMGA2 is an early event in the pathway to tumor formation. Here, we show evidence that three novel transcripts, A15, B6 and D12 are located within the HMGA2 gene itself and are transcribed from the opposite strand. These embedded transcripts are expressed at 6-20-fold higher levels in tumors compared to matched myometrium from the same patients. We estimate that the domain of increased expression extends 500kb on chromosome 12q15, and encompasses the majority of t(12;14) translocation breakpoints. However, a corresponding domain of consistently altered expression is not seen on chromosome 14 or outside of the chromosome 12 multiple aberration region. These data suggest that t(12;14) breakpoints contribute to the pathogenesis of uterine leiomyoma by interrupting a complex regulation of HMGA2 and other genes embedded within and around it. We also discovered a novel laminin receptor gene, transcribed from the opposite strand, within the promoter region of HMGA2. Although the roles for these embedded transcripts are still unknown, preliminary data suggest that they are members of the family of non-coding RNA and that they may play an important role in the pathology of uterine leiomyoma.

Surgical treatment of fibroids for subfertility

BACKGROUND

Fibroids are benign tumours of the uterus occurring in up to 77% of women. Fibroids have been noted to occur more frequently in women with infertility. Retrospective studies have suggested the benefit of surgically removing fibroids to increase the fertility efficacy of both natural conception and assisted conception. There are a variety of methods to surgically remove fibroids including laparotomy, laparoscopy and hysteroscopy. The relative advantages and disadvantages of these modalities in terms of fertility efficacy and side effects are unknown.

OBJECTIVES

To determine the efficacy and safety of the removal of uterine fibroids in subfertile women by laparotomy, laparoscopy or hysteroscopy when compared with expectant management or each other. The review will include also new surgical approaches as and when they are trialed.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Review Group Specialised register of controlled trials, MEDLINE (PUBMED) 1985 to 2004, EMBASE (1985 to 2004), CINAHL (1985 to 2004) and National Research Register.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in which fibroids were removed via surgery for the treatment of infertility

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trial quality and extracted data.

MAIN RESULTS

Only one randomized controlled study was included (131 women) and this was probably underpowered. There was no evidence of a difference in outcome in terms of clinical pregnancy rate and live birth rate when fibroids were removed via laparotomy or laparoscopy for infertility. There were some non fertility benefits of removal via laparoscopy including shorter hospital stay, less febrile illness and a smaller drop in pre-operative haemoglobin concentration when compared to laparotomy. There were no randomised controlled studies comparing hysteroscopic removal or no intervention with other surgical modalities.

AUTHORS' CONCLUSIONS

There is limited evidence to suggest that there is no difference in fertility efficacy outcome if fibroids are removed via laparotomy when compared to laparoscopy. There is no good randomised controlled evidence to support hysteroscopic removal of fibroids compared to other surgical modalities for fertility efficacy.

Expression of HMGA2 variants during oogenesis and early embryogenesis of Xenopus laevis

The high mobility group proteins A2 (HMGA2) have been implicated in the control of cell proliferation and differentiation, in particular during embryogenesis. Here, we used Xenopus laevis to analyze HMGA2 gene expression patterns during oogenesis and early embryogenesis. We found two functional XlHMGA2 isoforms, which we named XlHMGA2alpha and XlHMGA2beta. As revealed by RT-PCR, real-time PCR and whole-mount in situ hybridization both mRNAs are maternally produced and stored in eggs. Whole-mount in situ hybridizations revealed a conspicuous redistribution of the XlHMGA2 transcripts during early embryogenesis. Initially, during oogenesis and in eggs, the transcripts are uniformly distributed in the cytoplasm. With activation of the eggs the transcripts accumulate near the animal pole and remain in the juxtanuclear regions of animal pole blastomeres until midblastula transition. According to real-time PCR data, XlHMGA2alpha appears to be preferentially expressed during oogenesis and after midblastula transition, whereas XlHMGA2beta expression predominates after neurulation, suggesting an individual transcriptional regulation.

Energetics of binding the mammalian high mobility group protein HMGA2 to poly(dA-dT)2 and poly(dA)-poly(dT)

The mammalian high mobility group protein A2 (HMGA2) is a chromosomal architectural transcription factor involved in oncogenesis and cell transformation. It has three "AT-hook" DNA binding domains, which specifically bind to the minor groove of AT DNAs. The interaction of HMGA2 with poly(dA-dT)2 and poly(dA)poly(dT) has been investigated using the ethidium displacement assay, isothermal titration calorimetry, and UV melting studies. Each AT hook DNA binding domain was found to bind to 5 bp and each HMGA2 molecule binds to 15 bp. Although an individual AT hook DNA binding domain binds to AT DNAs with moderate affinity, HMGA2 binds with very high affinity to both DNAs in solutions containing 20 mM Na+ at 25 degrees C. The K(a) and binding enthalpy for poly(dA-dT)2 were determined to be, respectively, 1.9x10(14)M(-1) and -29.1(+/-0.5)kcal/mol. The binding reaction is enthalpy-driven with a favorable free energy of -19.5 kcal/mol and unfavorable entropy of -32.5 cal/mol K (-TDeltaS= +9. 7kcal/mol) at a 1M reference state. Interestingly, although HMGA2 binds to poly(dA)poly(dT) with a binding constant of 9.6x10(12) M(-1), the binding reaction is entropy-driven with an unfavorable enthalpy of +0.6 kcal/mol, a free energy of -17.7 kcal/mol and an entropy of +61.4 cal/mol K (-TDeltaS=-18.3 kcal/mol) at the 1 M state. The enthalpy-entropy compensation is similar to that of several minor groove-binding drugs such as netropesin, distamycin A and Hoechst33258 and may be a reflection of dehydration difference of different ligand-DNA complexes. The salt-dependence of the binding constant of HMGA2 with both DNAs showed that electrostatic interaction is a dominant force for the binding reactions. The temperature dependence of binding enthalpy for poly(dA-dT)2 indicates a large heat capacity of binding of -705(+/-113) cal/molK, consistent with an important role of solvent displacement in the linked folding/binding processes in this system.

HMGA1 proteins in human atherosclerotic plaques

One of the major characteristics of atherosclerosis is the migration of smooth muscle cells (SMC) from the tunica media to the intima, caused by alterations in the environment, e.g. mechanical, chemical, or immunologic injuries of the arterial walls. A group of molecules that may act as a main regulator of SMC phenotype switching is formed by the so-called HMGA1 high-mobility group proteins. One target gene of the HMGA1 protein, playing a major role in the development of atherosclerotic lesions, is CD44. The expression of CD44 is regulated by IL-1beta, but binding of HMGA1 potentiates the transactivation of the CD44 promoter. In this study, the HMGA1 expression of human atherosclerotic plaque samples was examined. Compared to the non-active components, all major components of the well-developed atherosclerotic plaques showed strong positivity of the high-mobility group protein HMGA1 in their activated areas, e.g. neointimal SMCs, macrophages, newly built blood vessels. This report is the first to describe HMGA1 as one of the first mediators in the development of human atherosclerotic plaques.

Extensive expression studies revealed a complex alternative splicing pattern of the HMGA2 gene

Chromosomal rearrangements of the HMGA2 locus belong to the most common aberrations in human benign tumors. HMGA2 rearrangements often result in chimeric genes expressing transcripts consisting of the first three exons of HMGA2 followed by ectopic sequences derived from intron 3 of that gene. RT-PCR-based expression studies of 4 of these HMGA2 transcripts revealed a co-expression with the "wild-type" HMGA2a in tumor samples as well as in normal tissues. Northern blot hybridizations of the lipoma cell line Li-14 revealed the expression of five additional HMGA2 transcripts consisting of exons 1 to 3 but not exons 4 to 5 besides the full-length HMGA2a transcript. In silico analyses have been performed showing a high homology to well-established consensus sequences for the 3' splice acceptor site, the branch site, and poly(A) signal. Thus, it is quite obvious that the HMGA2 transcripts described herein are alternative, not aberrant, splice-products of the HMGA2 gene. It is hypothesized that HMGA2-dependent tumorigenesis is caused by a disturbed equilibrium in the co-expression of the HMGA2 splice variants leading to aberrant cell proliferation and/or malignant transformation of cells.

Expression profile of tuberin and some potential tumorigenic factors in 60 patients with uterine leiomyomata

Human uterine leiomyomata are the most common tumors in women of reproductive age. The pathogenesis of leiomyomata remains unknown. An animal model of Eker rats with deleted tuberous sclerosis complex gene 2 (tuberin) shows increased incidence of leiomyomata. The role of tuberin in human leiomyomata is unknown. In this study, we designed a tissue microarray with tissue cores of leiomyomata and the matched myometrium from 60 hysterectomy specimens. We examined the expression of tuberin and tuberous sclerosis complex gene 1 product hamartin, proteins of the insulin-signaling pathway, steroid receptors and some of their cofactors, and human mobility group gene A2 by immunohistochemistry. We found that nearly half of the cases displayed either reduction or loss of tuberin in leiomyomata compared with matched normal myometrium. No change of hamartin was noted. Furthermore, a significant reduction of glucocorticoid receptor was found in leiomyomata with reduced tuberin. The proteins insulin like growth factor 1, insulin-like growth factor receptor beta, AKT kinase, and phosphatidylinositol 3-kinase were upregulated. Nearly half of leiomyomata show upregulation of human mobility group gene A2, along with the steroid receptor cofactors. Our findings suggest that there are two broad groups of uterine leiomyomata. One group is associated with an alteration of tuberin and glucocorticoid receptor. The other group is associated with upregulation of human mobility group gene A2 and steroid receptor cofactors.

Expression of the high mobility group proteins HMGI(Y) correlates with malignant progression in Barrett's metaplasia

Expression of the high mobility group proteins HMGI(Y) has been shown to be a marker of malignancy in thyroid and pancreatic lesions and to correlate significantly with malignant progression in the colon. The aim of this study was to determine whether HMGI(Y) expression is associated with malignant progression in Barrett's metaplasia (BM). Immunoperoxidase staining for HMGI(Y) was performed on sections of formalin-fixed paraffin-embedded endoscopic esophageal biopsies from 42 patients with BM. These consisted of 19 biopsies negative for dysplasia (ND), 16 with low-grade dysplasia (LGD)/indeterminate for dysplasia (IND), and 7 with high-grade dysplasia (HGD)/adenocarcinoma (CA). The percentage of positive cells was recorded, and nuclear HMGI(Y) immunoreactivity in >10% of the cells was considered positive. Statistical analysis was performed using Fisher's exact test. Positive HMGI(Y) staining was detected in 2 of 19 (11%) cases ND, 5 of 16 (30%) LGD/IND cases, and 7 of 7 (100%) HGD/CA cases. Biopsies with HGD/CA were significantly more likely to be positive for HMGI(Y) than biopsies ND (P < 0.0001) or with LGD/IND (P = 0.0046). We conclude that HMGI(Y) expression is significantly associated with malignant progression in BM. Additional studies are needed to determine whether BM biopsies that are ND or LGD/IND and positive for HMGI(Y) are more likely to progress to adenocarcinoma.

High-mobility group protein 1(Y): Metastasis-associated or metastasis-inducing?

Metastasis is the major cause of mortality and morbidity for patients with cancer. The high-mobility group protein 1(Y) [HMG-1(Y)] has a role in the transcription of many genes involved at different steps in the metastatic cascade and has been linked with cancer in human and animal models. This may represent a potential therapeutic target for patients. The following review summarizes and critically appraises the evidence for the role of HMG-1(Y) in metastasis.

High mobility group A2 protein and its derivatives bind a specific region of the promoter of DNA repair gene ERCC1 and modulate its activity

High mobility group A2 (HMGA2) chromosomal non-histone protein and its derivatives play an important role in development and progression of benign and malignant tumors, obesity and arteriosclerosis, although the underlying mechanisms of these conditions are poorly understood. Therefore, we tried to identify target genes for this transcriptional regulator and to provide insights in the mechanism of interaction to its target. Multiple genes have been identified by microarray experiments as being transcriptionally regulated by HMGA2. Among these we chose the ERCC1 gene, encoding a DNA repair protein, for this study. DNA-binding studies were performed using HMGA2 and C-terminally truncated DeltaHMGA2, a derivative that is frequently observed in a variety of tumors. A unique high affinity HMGA2 binding site was mapped to a specific AT-rich region located -323 to -298 upstream of the ERCC1 transcription start site, distinguishing it from other potential AT-rich binding sites. The observed 1:1 stoichiometry for the binding of wild-type HMGA2 to this region was altered to 1:2 upon binding of truncated DeltaHMGA2, causing DNA bending. Furthermore, the regulatory effect of HMGA2 was confirmed by luciferase promoter assays showing that ERCC1 promoter activity is down-regulated by all investigated HMGA2 forms, with the most striking effect exerted by DeltaHMGA2. Our results provide the first insights into how HMGA2 and its aberrant forms bind and regulate the ERCC1 promoter.

Uterine leiomyoma in the Eker rat: A unique model for important diseases of women

Eker rats carry a defect in the Tsc-2 tumor suppressor gene and female Eker rats develop uterine leiomyoma with a high frequency. The presentation, response to hormones and molecular alterations in these mesenchymal smooth muscle tumors, closely resembles their cognate human disease. Female rats and tumor-derived cell lines from Eker rat leiomyomas (ELT lines) have been developed as an in vivo/in vitro model system for preclinical studies to identify novel therapeutic agents for this disease and for studying disease pathogenesis. In addition to serving as a model for uterine leiomyoma, Eker rats have proven valuable for studying lymphangioleiomyomatosis, a related proliferative smooth muscle disease of women.

Angiomyofibroblastoma of the vulva: report of a case with immunohistochemical and molecular analysis

A 43-year-old woman presented with a mass in the subcutaneous tissue of the right labium majus. A lipoma or Bartholin gland cyst was suspected and excision of the lesion was performed. The lesion was well circumscribed, and histological examination revealed a typical angiomyofibroblastoma. The lesion was composed of alternating hypocellular edematous and hypercellular areas with abundant vessels, and plump tumor cells were loosely dispersed or aggregated mainly around the vessels. Tumor cells were immunoreactive for vimentin and desmin but negative for muscle actins. Ultrastructurally, the tumor cells contained a moderate amount of rough endoplasmic reticulum and abundant intermediate filaments, and had primitive junctions. Pinocytotic vesicles or basal lamina were not evident. Immunohistochemical studies also revealed that the tumor cells expressed basic fibroblast-growth factor, vascular-endothelial-growth factor, and stem-cell factor, factors that may contribute to the rich vascularity and mast cells within the tumor. Reverse transcription-polymerase chain reaction detected high mobility group I-C (HMGI-C) transcripts in the tumor tissue. Because the expression of HMGI-C is regulated by developmental and differentiation processes and is not found in adult normal tissues, HMGI-C may be involved in the tumorigenesis of angiomyofibroblastoma.

HMGA2 is expressed in an allele-specific manner in human lipomas

The architectural transcription factor HMGA2 is almost exclusively expressed in undifferentiated mesenchymal cells. Interestingly, it has been mapped to the translocation site in a variety of human mesenchymal tumors that reveal a terminally differentiated phenotype. The expression of chimeric HMGA2 transcripts encoding three DNA-binding domains fused to novel transcriptional regulatory domains was previously described in lipomas. In this study with lipoma ST91-198, we report the expression of truncated HMGA2 transcripts that gained no functional domains. The highly polymorphic region in the 5' untranslated region (UTR) of HMGA2 was used to determine the allele-specific expression of HMGA2 in lipomas. Microsatellite PCR revealed a monoallelic expression pattern, and only the translocated allele was expressed when the DNA-binding domains of the rearranged allele were fused with transcription activation domains. Surprisingly, a diallelic expression pattern of HMGA2 was observed in lipoma ST91-198, and the wild-type allele was also expressed. In conjunction with studies involving rearrangements of HMGA genes in other benign mesenchymal tumors, our results support a model in which the expression of the wild-type HMGA allele is critical for the pathogenesis of mesenchymal tumors and in which rearrangements of HMGA do not lead to a gain of function in the chimeric HMGA protein.

Expression of high-mobility-group-protein HMGI-C mRNA in the peripheral blood is an independent poor prognostic indicator for survival in metastatic breast cancer

HMGI-C belongs to the high-mobility-group-protein (HMG) family of architectural transcription factors and considerable interest has recently been shown in its expression in neoplastic tissues and apparent involvement in tumorigenesis. We could previously demonstrate an expression of HMGI-C mRNA in the peripheral blood of breast cancer patients for the first time. In this prospective study, we evaluated the independent prognostic power of HMGI-C mRNA expression in the peripheral blood of an unselected cohort of 69 patients with metastatic breast cancer using a hemi-nested reverse transcriptase polymerase chain reaction (RT-PCR) followed by sequence analysis of the resulting PCR products. Multivariate analysis was performed using the Cox regression model. HMGI-C mRNA was detected in peripheral blood from 21 out of 69 (30%) patients with metastatic breast cancer. Median survival was 15.9 months in patients expressing HMGI-C, while in the group of patients without HMGI-C expression the median survival had not been reached yet after a median follow-up of 24.7 months and 85.4% were still alive in this group. Disease-specific survival was significantly worse for patients positive for HMGI-C in comparison to those not expressing HMGI-C (P=0.0001). In a multivariate regression analysis, HMGI-C remained an independent prognostic factor for overall survival (P=0.001) besides oestrogen receptor status (P=0.024) and presence of metastases in liver and lungs (P=0.029). HMGI-C expression in the peripheral blood of patients with metastatic breast cancer is a powerful independent indicator for poor overall survival and this is the first study to demonstrate its prognostic relevance in univariate and multivariate analysis.

HMGIC alterations in smooth muscle tumors of soft tissues and other sites

The HMGIC gene, which codes a protein that acts as an architectural transcription factor, is frequently rearranged in a variety of benign or locally aggressive mesenchymal tumors. In tumors of smooth muscle differentiation, only uterine leiomyoma and lipoleiomyoma are known to be associated with the altered HMGIC. We investigated molecular and genetic alterations of the HMGIC in 36 benign and malignant smooth muscle tumors arising at various anatomical sites, including 13 uterine leiomyomas, two leiomyomas of the kidney with a t(12;14), one pelvic lipoleiomyoma, one vascular leiomyoma of the foot, two uterine leiomyosarcomas, six retroperitoneal leiomyosarcomas, one leiomyosarcoma of the urinary bladder, and 10 leiomyosarcomas of external soft tissues. HMGIC gene expressions were detected in both uterine (73.3%) and extrauterine (57.1%) smooth muscle tumors by reverse transcriptase polymerase chain reaction (RT-PCR), and benign tumors (70.5%) more frequently expressed the HMGIC than leiomyo-sarcomas (57.8%). Variant transcripts of the HMGIC containing cryptic exonic sequences previously described were found in one renal and three uterine leiomyomas and four leiomyosarcomas arising in the uterus and soft tissues by RT-PCR. Southern blot analysis identified a rearranged HMGIC in one soft tissue leiomyosarcoma. Thus, the HMGIC alterations in smooth muscle tumors are not confined only to uterine leiomyoma or lipoleiomyoma. Our data expand the variety of mesenchymal tumors associated with HMGIC alterations.

Sequencing of intron 3 of HMGA2 uncovers the existence of a novel exon

Aberrations affecting the gene encoding the high mobility group protein HMGA2 (formerly HMGIC) have been found in a variety of human tumors, e.g., uterine leiomyomas, lipomas, and pulmonary chondroid hamartomas. These aberrations lead to fusion genes, transcriptional up-regulation, or aberrant transcripts of HMGA2. In the latter case, truncated transcripts consisting of exons 1 to 3 of HMGA2, encoding the three DNA-binding domains, and ectopic sequences derived from chromosome 12 are frequent. There are several lines of evidence indicating that the biological and tumorigenic features of truncated HMGA2 derivatives, i.e., those composed of the DNA-binding domains and a shortened acidic tail, clearly differ from those of the normal protein consisting of three DNA-binding domains and one large acidic tail. By sequencing the complete 112 kb third intron of HMGA2, we were able to detect several of the ectopic sequences, known as fused to HMGA2. Expression studies revealed co-expression of one of these transcripts with the normal transcript in tumors with 12q14-15 aberrations as well as in other tumors, and in normal tissues. Thus, this transcript (HMGA2b) is flanked by an alternative terminal exon of HMGA2. Due to the loss of the part encoding the acidic tail, the expression of the latter transcript may have more striking effects than the "wild type" HMGA2 (HMGA2a) in terms of tumorigenesis. This finding clearly indicates that functional studies also should address the role of the HMGA2b transcript.

The expression of HMGA genes is regulated by their 3'UTR

Many benign mesenchymal tumors are characterized by chromosomal abnormalities of the regions 12q15 or 6p21.3 leading to aberrant expression of either HMGA2 (formerly HMGIC) or HMGA1 (formerly HMGIY). The proteins of both genes belong to the HMGA (formerly HMGI(Y)) family of architectural transcription factors. As a rule, aberrant HMGA transcripts found in a variety of benign tumors have intact coding regions at least for the DNA binding domains with a truncation of their 3' untranslated regions. Adding this to the finding that an altered HMGA protein level is not always correlated with an increased amount of corresponding mRNA indicates a posttranscriptional expression control mediated by regulatory elements within the 3'UTR. To check if HMGA expression is under control of such elements we performed luciferase assays with several HMGA2 and HMGA1 3'UTRs of different length. Experiments showed that an up to 12-fold increase in luciferase activity is obtained by the truncation of the 3'UTRs suggesting that the expression of HMGA2 and HMGA1 is controlled by negatively acting regulatory elements within their 3'UTR. Chromosomal aberrations affecting the HMGA genes may therefore influence their expression by an altered stability of the truncated transcripts as a result of the cytogenetic aberrations.

Localization of a gene (MCUL1) for multiple cutaneous leiomyomata and uterine fibroids to chromosome 1q42.3-q43

Dominant transmission of multiple uterine and cutaneous smooth-muscle tumors is seen in the disorder multiple leiomyomatosis (ML). We undertook a genomewide screen of 11 families segregating ML and found evidence for linkage to chromosome 1q42.3-q43 (maximum multipoint LOD score 5.40). Haplotype construction and analysis of recombinations permitted the minimal interval containing the locus, which we have designated "MCUL1," to be refined to an approximately 14-cM region flanked by markers D1S517 and D1S2842. Allelic-loss studies of tumors indicated that MCUL1 may act as a tumor suppressor. Identification of MCUL1 should have wide interest, since this gene may harbor low-penetrance variants predisposing to the common form of uterine fibroids and/or may undergo somatic mutation in sporadic leiomyomata.

Detection of HMGI-C in the peripheral blood of breast cancer patients

The human high mobility group (HMG) protein (HMGI-C) belongs to the HMG family of architectural transcription factors which are expressed only during embryonic development, and not in normal adult tissues. Considerable interest has recently been shown in HMGI-C and its expression in a variety of neoplastic tissues, whereas no expression could be found in normal tissue adjacent to the tumour. So far, no data is available on the expression of HMGI-C in the peripheral blood of patients with solid tumours. In this study we analysed the expression of HMGI-C in peripheral blood samples of 61 patients with breast cancer and 35 healthy donors using a haemi-nested reverse transcriptase-polymerase chain reaction (RT-PCR) technique. No HMGI-C could be detected in any of the healthy donors' samples. In the three prognostic groups according to the Nottingham Prognostic Score, the proportion of patients expressing HMGI-C differed significantly (P=0.001). The worse the prognosis was, the more patients expressed HMGI-C. This is the first report on the expression of HMGI-C in the peripheral blood of patients with breast cancer and our data suggest that this expression is correlated with a poor prognosis.

Molecular cytogenetic analysis of uterine leiomyoma and leiomyosarcoma by comparative genomic hybridization

Uterine leiomyomata are among the most common of human neoplasms and are associated with abnormal uterine bleeding, infertility, and abdominal pain. Uterine leiomyosarcomata are presumed to be the malignant counterpart to uterine leiomyomata and are very rare. Transformation of uterine leiomyoma (ULM) into uterine leiomyosarcoma (ULMS) is yet to be conclusively confirmed, and each type of tumor may represent a distinct genetic entity. We used comparative genomic hybridization (CGH) to evaluate DNA sequence copy-number changes in 12 specimens of ULM and 8 of ULMS. CGH analysis of ULM demonstrated chromosomal imbalances in 8 of 12 (66. 7%) specimens. The most frequent ULM gains were observed at 9q34 (a novel finding) and on chromosome 19. Other ULM imbalances included gains and losses of chromosome 1p, losses on 7q, and gains on 12q. All ULMS specimens demonstrated chromosomal aberrations. Chromosome 1 imbalances were very prominent. The most frequent losses were detected on 14q and 22q. Losses on 14q are rarely seen in other types of leiomyo-sarcoma and may be a distinctive feature of ULMS. Gains on chromosomes 8, 17, and X were observed in half the cases and were accompanied by high-level amplification. Other chromosome arms overrepresented included 12q and 19p. The absence of specific anomalies common to all ULM and ULMS argues against their being benign-malignant counterparts.