Transforming growth factor-alpha, epidermal growth factor receptor, and PCNA immunoexpression in uterine leiomyosarcomas and leiomyomas in B6C3F1 mice

Orthosiphon stamineus Extracts Inhibits Proliferation and Induces Apoptosis in Uterine Fibroid Cells

Objectives: The effects of water and 50% ethanolic-water extracts of Orthosiphon stamineus Benth (OS) on cell proliferation and apoptotic activity against uterine leiomyosarcoma (SK-UT-1) cells were investigated. Methods: Anti-proliferation effect was evaluated through cell cycle analysis whereas apoptotic activity was determined via screening and quantifying using fluorescence microscopy and flow cytometric analysis, respectively. The effect of extracts on molecular mechanism was studied using real-time reverse transcription polymerase chain reaction and Western blotting. Results: Cell cycle flow cytometric analysis showed the induction of cell cycle arrests were behaves in a p53-independent manner. The examination using fluorescence microscopy and Annexin V flow cytometry revealed the presence of morphological features of apoptotic bodies. Downregulation of anti-apoptotic gene (Bcl-2) supports the apoptotic activity of OS extracts although poorly induce PARP-1 cleavage in Western blot analysis. The extracts also inhibit the SK-UT-1 growth by suppressing VEGF-A, TGF-β1 and PCNA genes, which involved in angiogenesis and cell proliferation. Conclusion: This study demonstrates that O. stamineus extracts are able to inhibit proliferation and induced apoptosis of uterine fibroid cells and is worth further investigation.

Growth factors and pathogenesis

Growth factors are relatively small and stable, secreted or membrane-bound polypeptide ligands, which play an important role in proliferation, differentiation, angiogenesis, survival, inflammation, and tissue repair, or fibrosis. They exert multiple effects through the activation of signal transduction pathways by binding to their receptors on the surface of target cells. A number of studies have demonstrated the central role of growth factors and their signaling pathways in the pathogenesis of uterine leiomyomas. Numerous differentially expressed growth factors have been identified in leiomyoma and myometrial cells. These growth factors can activate multiple signaling pathways (Smad 2/3, ERK 1/2, PI3K, and β-catenin) and regulate major cellular processes, including inflammation, proliferation, angiogenesis, and fibrosis which are linked to uterine leiomyoma development and growth. In this chapter, we discuss the role of growth factors and their signaling pathways in the pathogenesis of uterine leiomyomas.

Immunohistochemical detection of promyelocytic leukemia zinc finger and histone 1.5 in uterine leiomyosarcoma and leiomyoma

OBJECTIVES

The accurate distinction of leiomyoma from leiomyosarcoma is essential for patient management. However, the distinction can be difficult to make, particularly in tissue biopsy samples. Immunohistochemistry has been established as a useful technique to aid in the diagnosis of malignancies. The advantages of immunohistochemical studies are their ease of use and interpretation. This study is the first to evaluate the utility of the promyelocytic leukemia zinc finger (PLZF) protein and the histone 1.5 (H1.5) protein as potential diagnostic immunohistochemical markers for distinguishing leiomyosarcoma from leiomyoma.

METHODS

Tissue samples from 21 leiomyosarcomas and 26 leiomyomas were studied. The student t-test and the Fisher exact test were used to calculate the differences in staining between the 2 groups.

RESULTS

Statistically significant differences were found in the staining indices of anti-PLZF and anti-H1.5 when comparing benign and malignant tumors (P < .0001 and P < .0001, respectively). The mean H1.5 staining score in leiomyosarcomas was 158.3, compared to 28.3 in leiomyomas. The mean PLZF score in leiomyosarcomas was 1.5 in contrast to 71.5 in leiomyomas. For H1.5 at a score ≥60, the sensitivity and specificity were 90.5% and 84.6%, respectively. For PLZF, a score ≤15 had a test sensitivity and specificity of 100% and 80.8%, respectively. This suggests that staining for H1.5 or PLZF can serve as a good screening test. Additionally, combining the 2 immunostains results in a sensitivity and specificity of 90.5% and 97.5%, respectively, in differentiating between leiomyoma and leiomyosarcoma.

CONCLUSIONS

We describe immunostaining for PLZF and H1.5 in benign and malignant uterine smooth muscle tumors. Statistically significant differences in staining patterns were found, suggesting utility in distinguishing leiomyosarcomas from leiomyomas.

Nonproliferative and proliferative lesions of the rat and mouse female reproductive system

The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) Project (www.toxpath.org/inhand.asp) is a joint initiative of the Societies of Toxicological Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in the female reproductive tract of laboratory rats and mice, with color photomicrographs illustrating examples of some lesions. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous and aging lesions as well as lesions induced by exposure to test materials. There is also a section on normal cyclical changes observed in the ovary, uterus, cervix and vagina to compare normal physiological changes with pathological lesions. A widely accepted and utilized international harmonization of nomenclature for female reproductive tract lesions in laboratory animals will decrease confusion among regulatory and scientific research organizations in different countries and provide a common language to increase and enrich international exchanges of information among toxicologists and pathologists.

Analysis of Epithelial Growth Factor-Receptor (EGFR) Phosphorylation in Uterine Smooth Muscle Tumors: Correlation to Mucin-1 and Galectin-3 Expression

Uterine fibroids are the commonest uterine benign tumors. A potential mechanism of malignant transformation from leiomyomas to leiomyosarcomas has been described. Tyrosine phosphorylation is a key mechanism that controls biological functions, such as proliferation and cell differentiation. The aim of the current study was to evaluate the phosphorylation of epithelial growth factor-receptor (EGFR) in normal myometrium, uterine myomas and uterine leiomyosarcomas. Formalin-fixed paraffin-embedded tissue samples from normal myometrium, leiomyomas and leiomyosarcomas were studied. Samples were immunohistochemically (IHC) assessed using the anti-EGFR phosphorylation of Y845 (pEGFR-Y845) and anti-pEGFR-Y1173 phosphorylation-specific antibodies. IHC staining was evaluated using a semiquantitative score. The expression of pEGFR-Y845 was significantly upregulated in leiomyosarcomas (p < 0.001) compared to leiomyomas and normal myometrium. In contrast, pEGFR-Y1173 did not differ significantly between the three groups of the study. Correlation analysis revealed an overall positive correlation between pEGFR Y845 and mucin 1 (MUC1). Further subgroup analysis within the tumoral group (myomas and leiomyosarcomas) revealed an additional negative correlation between pEGFR Y845 and galectin-3 (gal-3) staining. On the contrary no significant correlation was noted within the non-tumoral group. An upregulated EGFR phosphorylation of Y845 in leiomyosarcomas compared to leiomyomas implicates EGFR activation at this special receptor site. Due to these pEGFR-Y845 variations, it can be postulated that MUC1 interacts with it, whereas gal-3 seems to be cleaved from Y845 phosphorylated EGFR. Further research on this field could focus on differences in EGFR pathways as a potentially advantageous diagnostic tool for investigation of benign and malignant signal transduction processes.

Growth factors and myometrium: biological effects in uterine fibroid and possible clinical implications

BACKGROUND

Growth factors are proteins secreted by a number of cell types that are capable of modulating cellular growth, proliferation and cellular differentiation. It is well accepted that uterine cellular events such as proliferation and differentiation are regulated by sex steroids and their actions in target tissues are mediated by local production of growth factors acting through paracrine and/or autocrine mechanisms. Myometrial mass is ultimately modified in pregnancy as well as in tumour conditions such as leiomyoma and leiomyosarcoma. Leiomyomas, also known as fibroids, are benign tumours of the uterus, considered to be one of the most frequent causes of infertility in reproductive years in women.

METHODS

For this review, we searched the database MEDLINE and Google Scholar for articles with content related to growth factors acting on myometrium; the findings are hereby reviewed and discussed.

RESULTS

Different growth factors such as epidermal growth factor (EGF), transforming growth factor-α (TGF-α), heparin-binding EGF (HB-EGF), acidic fibroblast growth factor (aFGF), basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), insulin-like growth factor (IGF), platelet-derived growth factor (PDGF) and TGF-β perform actions in myometrium and in leiomyomas. In addition to these growth factors, activin and myostatin have been recently identified in myometrium and leiomyoma.

CONCLUSIONS

Growth factors play an important role in the mechanisms involved in myometrial patho-physiology.

Immunolocalization of VEGF, VEGF receptors, EGF-R and Ki-67 in leiomyoma, cellular leiomyoma and leiomyosarcoma

Angiogenic factors, such as vascular endothelial growth factor (VEGF), its receptors and epidermal growth factor receptor (EGF-R), are involved in increased progression in many carcinomas. The aim of this study was to investigate the role of angiogenesis and immunolocalization of VEGF, its receptors, EGF-R and Ki 67 in leiomyomas and leiomyosarcomas using an indirect immunohistochemical method. Samples from patients with leiomyoma, cellular leiomyoma and cellular leiomyosarcoma (n=20 per group) were fixed in 10% formalin and processed using routine paraffin protocols. Following initial histological analysis, samples were immunostained with primary antibodies for VEGF, VEGFR-1, VEGFR-2, EGF-R and Ki-67 using an indirect avidin-biotin peroxidase method. Immunostaining intensities were evaluated as mild, moderate or strong and a semi-quantitative method (H-Score) was used to compare the samples. While mild/moderate EGF-R immunostaining and moderate immunostaining for VEGF and its receptors were observed in samples of leiomyomas, much less immunoreactivity was observed in cellular leiomyomas. All immunoreactivities and immune-stained cells increased in leiomyosarcomas. When scores of intensity and percentage of positive staining cells were compared, all immunoreactivities were shown to be significantly increased in leiomyosarcomas compared to leiomyomas. These results suggest that in leiomyosarcoma, angiogenic factors, such as VEGF, its receptors and EGF-R, may be involved in tumor angiogenesis. Active tumor cells can trigger angiogenesis, interaction with surrounding tissue and in the tissue itself initiating angiogenic activity. Angiogenic growth factors play an important role and induce malignant transformation through both autocrine and paracrine mechanisms. Anti-angiogenic agents may provide a novel therapeutic approach for the treatment of leiomyosarcoma.

Incidence, aetiology and epidemiology of uterine fibroids

Uterine fibroids are the most common benign tumour of the female genital tract. However, their true prevalence is probably under-estimated, as the incidence at histology is more than double the clinical incidence. Recent longitudinal studies have estimated that the lifetime risk of fibroids in a woman over the age of 45 years is more than 60%, with incidence higher in blacks than in whites. The cause of fibroids remains unclear and their biology poorly understood. No single candidate gene has been detected for commonly occurring uterine fibroids. However, the occurrence of rare uterine fibroid syndromes, such as multiple cutaneous and uterine leiomyomatosis, has been traced to the gene that codes for the mitochondrial enzyme, fumarate hydratase. Cytogenetic abnormalities, particularly deletions of chromosome 7, which are found in up to 50% of fibroid specimens, seem to be secondary rather than primary events, and investigations into the role of tumour suppressor genes have yielded conflicting results. The key regulators of fibroid growth are ovarian steroids, both oestrogen and progestogen, growth factors and angiogenesis, and the process of apoptosis. Black race, heredity, nulliparity, obesity, polycystic ovary syndrome, diabetes and hypertension are associated with increased risk of fibroids, and there is emerging evidence that familial predisposition to fibroids is associated with a distinct pattern of clinical and molecular features compared with fibroids in families without this prevalence.

Characterization of uterine leiomyomas in CD-1 mice following developmental exposure to diethylstilbestrol (DES)

Experimental animal and clinical studies have well established the association of prenatal exposure to diethylstilbestrol (DES) and the subsequent development of reproductive tract abnormalities, including poor reproductive outcome and neoplasia. Overwhelmingly, the focus has been on DES-induced epithelial lesions, particularly vaginal adenosis and adenocarcinoma; however, uterine smooth muscle cells are also recognized as cellular targets of DES. This descriptive report characterizes uterine leiomyomas that occur in outbred CD-1 mice following exposure to DES prenatally on days 9 to 16 of gestation or on neonatal days 1 to 5. These DES-induced uterine leiomyomas have typical histomorphologic, and some immunohistochemical characteristics of spontaneously occurring uterine smooth muscle tumors of B6C3F1 mice previously described in our laboratory, and they are also similar to uterine leiomyomas (fibroids) commonly observed in premenopausal women.

EGF family ligand-dependent phenotypic modulation of smooth muscle cells through EGF receptor

The phenotypic modulation of smooth muscle cells (SMCs) is closely associated with the development and progression of various SMC diseases. We investigated the molecular mechanism of phenotypic modulation triggered by EGF family ligands using a primary culture system of differentiated SMCs. Among four EGF-receptor (EGFR) family members, the EGFR was solely activated by EGF, heparin-binding EGF (HB-EGF), transforming growth factor alpha (TGF alpha), epiregulin (ER), and betacellulin (BTC), resulting in induction of phenotypic modulation of SMCs. This effect was mediated through the coordinated activation of the extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (p38MAPK) pathways. These results suggest that EGF family ligand- and EGFR-triggered signaling pathways are critically involved in the phenotypic modulation of SMCs.