Immunolabeling of the Inhibin-βA and -βB Subunit in Normal and Malignant Human Cervical Tissue and Cervical Cancer Cell Lines

Inhibin subunit beta B (INHBB): an emerging role in tumor progression

The gene inhibin subunit beta B (INHBB) encodes the inhibin βB subunit, which is involved in forming protein members of the transforming growth factor-β (TGF-β) superfamily. The TGF-β superfamily is extensively involved in cell proliferation, differentiation, adhesion, movement, metabolism, communication, and death. Activins and inhibins, which belong to the TGF-β superfamily, were first discovered in ovarian follicular fluid. They were initially described as regulators of pituitary follicle-stimulating hormone (FSH) secretion both in vivo and in vitro. Later studies found that INHBB is expressed not only in reproductive organs such as the ovary, uterus, and testis but also in numerous other organs, including the brain, spinal cord, liver, kidneys, and adrenal glands. This wide distribution implies its involvement in the normal physiological functions of various organs; however, the mechanisms underlying these functions have not yet been fully elucidated. Recent studies suggest that INHBB plays a significant, yet complex role in tumorigenesis. It appears to have dual effects, promoting tumor progression in some contexts while inhibiting it in others, although these roles are not yet fully understood. In this paper, we review the different expression patterns, functions, and mechanisms of INHBB in normal and tumor tissues to illustrate the research prospects of INHBB in tumor progression.

Immunostaining of βA-Activin and Follistatin Is Decreased in HPV(+) Cervical Pre-Neoplastic and Neoplastic Lesions

The activin-follistatin system regulates several cellular processes, including differentiation and tumorigenesis. We hypothesized that the immunostaining of βA-activin and follistatin varies in neoplastic cervical lesions. Cervical paraffin-embedded tissues from 162 patients sorted in control (n = 15), cervical intraepithelial neoplasia (CIN) grade 1 (n = 38), CIN2 (n = 37), CIN3 (n = 39), and squamous cell carcinoma (SCC; n = 33) groups were examined for βA-activin and follistatin immunostaining. Human papillomavirus (HPV) detection and genotyping were performed by PCR and immunohistochemistry. Sixteen samples were inconclusive for HPV detection. In total, 93% of the specimens exhibited HPV positivity, which increased with patient age. The most detected high-risk (HR)-HPV type was HPV16 (41.2%) followed by HPV18 (16%). The immunostaining of cytoplasmatic βA-activin and follistatin was higher than nuclear immunostaining in all cervical epithelium layers of the CIN1, CIN2, CIN3, and SCC groups. A significant decrease (p < 0.05) in the cytoplasmic and nuclear immunostaining of βA-activin was detected in all cervical epithelial layers from the control to the CIN1, CIN2, CIN3, and SCC groups. Only nuclear follistatin immunostaining exhibited a significant reduction (p < 0.05) in specific epithelial layers of cervical tissues from CIN1, CIN2, CIN3, and SCC compared to the control. Decreased immunostaining of cervical βA-activin and follistatin at specific stages of CIN progression suggests that the activin-follistatin system participates in the loss of the differentiation control of pre-neoplastic and neoplastic cervical specimens predominantly positive for HPV.

Obesity-related alterations in protein expression in human follicular fluid from women undergoing in vitro fertilization

OBJECTIVE

To compare the proteomic composition of follicular fluid from women with normal weight vs. women with obesity but without a history of polycystic ovary syndrome or known ovarian dysfunction undergoing in vitro fertilization.

DESIGN

Cross-sectional.

SETTING

Academic medical center.

PATIENT(S)

Eight women with normal weight and 8 women with obesity undergoing in vitro fertilization and without a history of polycystic ovary syndrome, ovulatory dysfunction, diminished ovarian reserve, or known endometriosis were included in the analysis.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Proteomic assessment using liquid chromatography-mass spectrometry analysis.

RESULT(S)

The mean age of women with normal weight was similar to that of women with obesity (32.9 vs. 32.6 years, not significant). The mean body mass index of women with normal weight was 21.2 kg/m² compared with a body mass index of 37.1 kg/m² in women with obesity. A total of 1,174 proteins were identified with ≥2 peptides present. Twenty-five proteins were found to be significantly altered in the follicular fluid from women with obesity. Of these 25 proteins, 19 were up-regulated and 6 were down-regulated. Notably, C-reactive protein was 11-fold higher in the follicular fluid from women with obesity than in the follicular fluid from women with normal weight.

CONCLUSION(S)

Obesity is associated with dysregulation at the level of the follicle, including alterations in proteins related to inflammation and metabolism. These include proteins with emerging roles in energy homeostasis and follicular regulation.

Activin and inhibin signaling: From regulation of physiology to involvement in the pathology of the female reproductive system

Activins and inhibins - comprising activin A, B, AB, C and E, and inhibin A and B isoforms - belong to the transforming growth factor beta (TGFβ) superfamily. They regulate several biological processes, including cellular proliferation, differentiation and invasiveness, to enhance the formation and functioning of many human tissues and organs. In this review, we have discussed the role of activin and inhibin signaling in the physiological and female-specific pathological events that occur in the female reproductive system. The up-to-date evidence indicates that these cytokines regulate germ cell development, follicular development, ovulation, uterine receptivity, decidualization and placentation through the activation of several signaling pathways; and that their dysregulated expression is involved in the pathogenesis and pathophysiology of the numerous diseases, including pregnancy complications, that disturb reproduction. Hence, some of the isoforms have been suggested as potential biomarkers and therapeutic targets for the management of some of these diseases. Tackling the research directions highlighted in this review will enhance a detailed comprehension and the clinical utility of these cytokines.

Evaluation of two commercialised in situ hybridisation assays for detecting HPV-DNA in formalin-fixed, paraffin-embedded tissue

INTRODUCTION

The role of human papilloma virus (HPV) in the pathogenesis of anogenital dysplasia is now conclusive. However, HPV detection in formalin-fixed and paraffin-embedded tissues remains controversial. Therefore, the aim of this study was to evaluate morphological changes directly in tissue specimens using a HPV-DNA detection system involving HPV in situ hybridisation.

MATERIALS AND METHODS

Samples from patients with cervical carcinoma were analysed using the GenPoint HPV DNA Probe Cocktail (Dako, Glostrup, Denmark) and the ZytoFast HPV Screening CISH-Kit (Zytomed, Berlin, Germany). Three cervical carcinoma cell lines with a well-defined HPV copy number per cell (SiHa, HeLa, and CaSki) served as positive controls for sensitivity testing, while two HPV-negative cell lines (AC-1M32, MCF-7) and brain tissue samples served as negative controls. Moreover, to assess the validity of the in situ hybridisation, the expression of HPV-16 DNA in cell lines was demonstrated by HPV-16 E6-specific PCR.

RESULTS

Both HPV-screening assays revealed strong signals of episomal and integrated HPV-DNA at a HPV copy number of more than 50 copies/cell. All cervical carcinoma samples were positive in the Dako assay, which identifies 13 high-risk HPV genotypes, whereas HPV-DNA could be detected in 9/10 cervical carcinoma samples using the Zytofast assay, identifying HPV 16, 18, 31, 33, and 35.

CONCLUSION

HPV in situ hybridisation is a convenient and powerful tool for detecting HPV-DNA in formalin-fixed and paraffin-embedded tissue samples. Therefore, this technique is suitable for analysis of a potential HPV infection using archival pathological slides.

Inhibin-betaA and -betaB subunits in normal and malignant glandular epithelium of uterine cervix and HeLa cervical cancer cell line

INTRODUCTION

Inhibins, dimeric peptide hormones composed of an alpha-subunit and one of two possible beta-subunits (betaA or betaB), exhibit substantial roles in human reproduction and in endocrine-responsive tumors. However, it is still unclear if normal and cancerous cervical glandular epithelial cells as well as cervical cancer cell lines of glandular origin express the inhibin-betaA and -betaB subunits.

MATERIALS AND METHODS

Normal cervical tissue samples and a total of 10 specimens of well-differentiated adenocarcinomas of the human cervix were analyzed for inhibin-betaA and -betaB subunit expression by immunohistochemical analysis. Additionally, the cervical carcinoma cell line HeLa was analyzed by immunofluorescence and RT-PCR analysis for the expression of inhibin subunits.

RESULTS

Immunolabeling of normal and malignant glandular epithelium of human cervical tissue revealed a positive staining reaction for the inhibin-betaA and -betaB subunits. Additionally, the cancer cell line HeLa synthesized both inhibin subunits. When compared to the normal cervical glandular epithelium, the expression of the inhibin beta subunits became significantly reduced in cervical adenocarcinoma tissues.

DISCUSSION

In conclusion, we demonstrated a strong, though differential expression pattern of inhibin-betaA and -betaB subunits in normal and malignant glandular epithelial cells of the human uterine cervix. Although the physiological role of inhibins is still quite unclear in cervical tissue, the expression of inhibin-beta-subunits might play an important role in cervical cancer carcinogenesis, since they are significantly down-regulated during pathogenesis in cervical adenocarcinomas.