Cellular retinol-binding protein-1 expression in endometrial stromal cells: physiopathological and diagnostic implications

Cellular retinol-binding protein 1: a therapeutic and diagnostic tumor marker

Cellular Retinol Binding Protein 1 (CRBP1) gene is a protein coding gene located on human chromosome 3q21, which codifies a protein named CRBP1. CRBP1 is widely expressed in many tissues as a chaperone protein to regulate the uptake, subsequent esterification and bioavailability of retinol. CRBP1 combines retinol and retinaldehyde with high affinity to protect retinoids from non-specific oxidation, and transports retinoids to specific enzymes to promote the biosynthesis of retinoic acid. The vital role of CRBP1 in retinoids metabolism has been gradually discovered, which has been implicated in tumorigenesis. However, the precise functions of CRBP1 in different diseases are still poorly understood. The purpose of this review is to provide an overview of the role of CRBP1 in various diseases, especially in both the promotion and inhibition of cancers, which may also offer a novel biomarker and potential therapeutic target for human diseases.

Cellular Retinoic-Acid Binding Protein 2 in Solid Tumor

The retinoic acid (RA) signaling pathway is crucial for many biological processes. The RA transporter, Cellular Retinoic-Acid Binding Protein 2 (CRABP2), is abnormally expressed in various tumor types. CRABP2 presents significant effects on tumorous behaviors and functions, including cell proliferation, apoptosis, invasion, migration, metastasis, and angiogenesis. The tumorigenesis mechanism of CRABP2, as both suppressor and promotor, is complicated, therefore, there remains the need for further investigation. Elucidating the regulating mechanisms in a specific stage of the tumor could facilitate CRABP2 to be a biomarker in cancer diagnosis and prognosis. Besides, clarifying the pathways of CRABP2 in cancer development will contribute to the gene-targeted therapy. In this review, we summarized the expression, distribution, and mechanism of CRABP2 in solid tumors. Illuminating the CRABP2 signaling pathway may benefit understanding the retinoid signaling pathway, providing a useful biomarker for future clinical trials.

The Usefulness of Immunohistochemistry in the Differential Diagnosis of Lesions Originating from the Myometrium

Uterine leiomyomas (LMs), currently the most common gynecological complaint around the world, are a serious medical, social and economic problem. Accurate diagnosis is the necessary prerequisite of the diagnostic-therapeutic process. Statistically, mistakes may occur more often in case of disease entities with high prevalence rates. Histopathology, based on increasingly advanced immunohistochemistry methods, is routinely used in the diagnosis of neoplastic diseases. Markers of the highest sensitivity and specificity profiles are used in the process. As far as LMs are concerned, the crux of the matter is to identify patients with seemingly benign lesions which turn out to be suspicious (e.g., atypical LM) or malignant (e.g., leiomyosarcoma (LMS)), which is not uncommon. In this study, we present the current state of knowledge about the use of immunohistochemical markers in the differential diagnosis of LM, atypical LM, smooth muscle tumors of uncertain malignant potential (STUMP), and LMS, as well as their clinical predictive value.

Composition of the Stroma in the Human Endometrium and Endometriosis

To analyze whether the endometrial and endometriotic microenvironment is involved in the pathogenesis of endometriosis, we characterized the stromal composition. We used CD90 for fibroblasts, α-smooth muscle actin for myofibroblasts as well as CD10 and CD140b for mesenchymal stromal cells. Quantification of eutopic endometrial stroma of cases without endometriosis showed a high percentage of stromal cells positive for CD140b (80.7%) and CD10 (67.4%), a moderate number of CD90-positive cells (57.9%), and very few α-smooth muscle actin-positive cells (8.5%). These values are highly similar to cases with endometriosis showing only minor changes: CD140b (76.7%), CD10 (63%), CD90 (53.9%), and α-smooth muscle actin (6.9%). There are no significant differences in the composition of CD140b- and CD10-positive stromal cells between the eutopic endometrial stroma and the 3 different endometriotic entities (ovarian, peritoneal, and deep infiltrating endometriosis), except for a significant difference between CD10-positive stromal cells in peritoneal lesions compared to ovarian lesions. However, the percentage of CD90-positive stromal cells was reduced in the 3 different endometriotic entities compared to the endometrium, especially significant in the ovarian lesions. In contrast, the percentage of α-smooth muscle actin-positive cells in the ovary was moderately increased. Taken together, the marker signature of eutopic endometrial and endometriotic stromal cells resembles mostly mesenchymal stromal cells. Our results show clearly that the proportion of the different stromal cell types in the endometrium with or without endometriosis does not differ significantly, thus suggesting that the stromal eutopic endometrial microenvironment does not contribute to the pathogenesis of endometriosis.

Comparison of tissue transglutaminase 2 and bone biological markers osteocalcin, osteopontin and sclerostin expression in human osteoporosis and osteoarthritis

Osteoporosis (OP) and osteoarthritis (OA) are the most common joint diseases, with a high incidence in the elderly population. OP is characterized by trabecular bone remodeling and reabsorption, whereas articular cartilage and subchondral bone remodeling are major features of OA. Although classically considered as independent or even conflicting processes, clinical coexistence of OP and OA was recently described. Transglutaminase 2 (TG2) expression is considered a biomarker of OA, but its role in osteoporotic bone remodeling is still uncertain. We investigated TG2 and bone biological markers (Osteocalcin, Osteopontin, and Sclerostin) in osteoporotic and osteoarthritic osteocartilagineous tissue (n = 54) and human chondrocyte cultures in vitro by immunohistochemistry, immunofluorescence and RT-PCR. Histomorphometric evaluation of bone trabecular remodeling was also performed. In cartilage, TG2 expression was faint in control and OP and significantly less than in OA and OP + OA chondrocytes; the opposite was found for Osteocalcin, whereas Osteopontin and Sclerostin expression was similar. In the subchondral trabecular bone, osteocytes/osteoblasts TG2 expression was slight and similar comparing control, OP, OA, and OP + OA group, whereas Osteocalcin and Osteopontin expression was lower in OP compared to control, OA and OP + OA. Increased TG2 and reduced Osteocalcin expression were maintained in human osteoarthritic chondrocytes in vitro. Histomorphometric analysis confirmed reduced trabecular bone mass in OP and OP + OA compared with OA patients. TG2 represented a suitable biomarker of osteoarthritic chondrocyte activation, whereas osteocalcin and osteopontin characterized osteoporotic osteocyte/osteoblast changes; differences were lost in OP + OA patients, suggesting careful consideration when coexistence of the two diseases occurs.

High expression of cellular retinol binding protein-1 in lung adenocarcinoma is associated with poor prognosis

Purpose

Adenocarcinoma, the most common non-small cell lung cancer is a leading cause of death worldwide, with a low overall survival (OS) despite increasing attempts to achieve an early diagnosis and accomplish surgical and multimodality treatment strategies. Cellular retinol binding protein-1 (CRBP-1) regulates retinol bioavailability and cell differentiation, but its role in lung cancerogenesis remains uncertain.

Experimental design

CRBP-1 expression, clinical outcome and other prognostic factors were investigated in 167 lung adenocarcinoma patients. CRBP-1 expression was evaluated by immunohistochemistry of tissue microarray sections, gene copy number analysis and tumor methylation specific PCR. Effects of CRBP-1 expression on proliferation/apoptosis gene array, protein and transcripts were investigated in transfected A549 lung adenocarcinoma cells.

Results

CRBP-1^High expression was observed in 62.3% of adenocarcinomas and correlated with increased tumor grade and reduced OS as an independent prognostic factor. CRBP-1 gene copy gain also associated with tumor CRBP-1^High status and dedifferentiation. CRBP-1-transfected (CRBP-1⁺) A549 grew more than CRBP-1⁻ A549 cells. At >1μM concentrations, all trans-retinoic acid and retinol reduced viability more in CRBP-1⁺ than in CRBP-1⁻ A549 cells. CRBP-1⁺ A549 cells showed up-regulated RARα/ RXRα and proliferative and transcriptional genes including pAkt, pEGFR, pErk1/2, creb1 and c-jun, whereas RARβ and p53 were strongly down-regulated; pAkt/pErk/ pEGFR inhibitors counteracted proliferative advantage and increased RARα/RXRα, c-jun and CD44 expression in CRBP-1⁺ A549 cells.

Conclusion

CRBP-1^High expression in lung adenocarcinoma correlated with increased tumor grade and reduced OS, likely through increased Akt/Erk/EGFR-mediated cell proliferation and differentiation. CRBP-1^High expression can be considered an additional marker of poor prognosis in lung adenocarcinoma patients.

Vitamin A, cancer treatment and prevention: the new role of cellular retinol binding proteins

Retinol and vitamin A derivatives influence cell differentiation, proliferation, and apoptosis and play an important physiologic role in a wide range of biological processes. Retinol is obtained from foods of animal origin. Retinol derivatives are fundamental for vision, while retinoic acid is essential for skin and bone growth. Intracellular retinoid bioavailability is regulated by the presence of specific cytoplasmic retinol and retinoic acid binding proteins (CRBPs and CRABPs). CRBP-1, the most diffuse CRBP isoform, is a small 15 KDa cytosolic protein widely expressed and evolutionarily conserved in many tissues. CRBP-1 acts as chaperone and regulates the uptake, subsequent esterification, and bioavailability of retinol. CRBP-1 plays a major role in wound healing and arterial tissue remodelling processes. In the last years, the role of CRBP-1-related retinoid signalling during cancer progression became object of several studies. CRBP-1 downregulation associates with a more malignant phenotype in breast, ovarian, and nasopharyngeal cancers. Reexpression of CRBP-1 increased retinol sensitivity and reduced viability of ovarian cancer cells in vitro. Further studies are needed to explore new therapeutic strategies aimed at restoring CRBP-1-mediated intracellular retinol trafficking and the meaning of CRBP-1 expression in cancer patients' screening for a more personalized and efficacy retinoid therapy.

The spectrum of cervical glandular neoplasia and issues in differential diagnosis

CONTEXT

Premalignant and malignant glandular lesions of the cervix are known to often cause diagnostic problems with a variety of benign (more common) as well as other malignant mimics, the latter setting often being represented by secondary involvement by endometrioid endometrial carcinoma especially in small samplings.

OBJECTIVE

To highlight key histologic features and immunohistochemical markers that may be helpful in the distinction of in situ endocervical carcinoma from benign glandular proliferations, and those that separate different subtypes of invasive endocervical carcinoma, as well as invasive carcinoma from other carcinomas secondarily involving the cervix and nonneoplastic proliferations of the cervix.

CONCLUSIONS

Clinical and morphologic features as well as immunohistochemistry results should be used in conjunction in the differential diagnosis of glandular proliferations of the cervix, as correct interpretation has major clinical consequences for the patient in most instances (especially benign versus malignant). Immunohistochemical markers should be used as part of a panel of antibodies, as exceptions may occur to the usual pattern of staining, and if used singly, they may mislead the pathologist to establish a wrong diagnosis.

Propionyl- l -Carnitine Improves Postischemic Blood Flow Recovery and Arteriogenetic Revascularization and Reduces Endothelial NADPH-Oxidase 4–Mediated Superoxide Production

Objective— The beneficial effect of the natural compound propionyl- l -carnitine (PLC) on intermittent claudication in patients with peripheral arterial disease is attributed to its anaplerotic function in ischemic tissues, but inadequate information is available concerning action on the vasculature.

Methods and Results— We investigated the effects of PLC in rabbit hind limb collateral vessels after femoral artery excision, mouse dorsal air pouch, chicken chorioallantoic membrane, and vascular cells by angiographic, Doppler flow, and histomorphometrical and biomolecular analyses. PLC injection accelerated hind limb blood flow recovery after 4 days ( P <0.05) and increased angiographic quadriceps collateral vascularization after 7 days ( P <0.001) Histomorphometry confirmed the increased vascular area ( P <0.05), with unchanged intramuscular capillary density. PLC-induced dilatative adaptation, and growth was found associated with increased inducible nitric oxide synthase and reduced arterial vascular endothelial growth factor and intracellular adhesion molecule-1 expression. PLC also increased vascularization in air pouch and chorioallantoic membrane ( P <0.05), particularly in large vessels. PLC increased endothelial and human umbilical vascular endothelial cell proliferation and rapidly reduced inducible nitric oxide synthase and NADPH-oxidase 4–mediated reactive oxygen species production in human umbilical vascular endothelial cells; NADPH-oxidase 4 also regulated NF-κB–independent intracellular adhesion molecule-1 expression.

Conclusion— Our results provided strong evidence that PLC improves postischemic flow recovery and revascularization and reduces endothelial NADPH-oxidase–related superoxide production. We recommend that PLC should be included among therapeutic interventions that target endothelial function.

Immunohistochemical Markers of Value in the Diagnosis of Mesenchymal Lesions of the Female Genital Tract

Pure mesenchymal tumors may occur anywhere in the female genital tract, but they are most common in the uterine corpus, leiomyoma being by far the most prevalent. These tumors, and other uncommon mesenchymal lesions within the uterine corpus and elsewhere in the female genital tract, may result in several diagnostic problems. Morphology remains paramount and, in most cases, an unequivocal diagnosis can be made based on examination of the hematoxylin and eosin stained sections, combined with an appreciation of the clinical and gross pathologic features. In difficult cases, immunohistochemistry can significantly contribute to the final diagnosis. In this article, the immunohistochemistry of neoplastic and nonneoplastic mesenchymal lesions of the female genital tract is discussed site by site, concentrating on markers that are of value in diagnosis and in differential diagnosis. The immunophenotype of mixed epithelial and mesenchymal neoplasms and pure epithelial neoplasms with a component of spindle cells is discussed, where appropriate, because these can enter into the differential diagnosis of a pure mesenchymal lesion.

The Ki67+ proliferation index correlates with increased cellular retinol-binding protein-1 and the coordinated loss of plakophilin-1 and desmoplakin during progression of cervical squamous lesions

AIMS

To investigate the modulation of cellular retinol-binding protein (CRBP)-1 and the desmosomal plaque proteins plakophilin (PKP)-1 and desmoplakin (DP) in correlation with the Ki67+ proliferation index (PI) during the progression of cervical squamous intraepithelial lesions (SIL) to squamous cell carcinoma (SCC).

METHODS

Using in situ imaging by brightfield and confocal laser scanning microscopy, the expression of CRBP-1 protein and transcripts, PKP-1, DP and the Ki67 PI were analysed in 38 low-grade (L) SIL, 56 high-grade (H) SIL, 49 SCC, 30 control cervices and 10 human papillomavirus-positive condylomatous lesions.

RESULTS

CRBP-1+ cells increased from 11.4% in the normal cervix to 80.3% in LSILs, 92.3% in HSILs and slightly decreased to 78.3% in invasive SCCs (P = 0.0001) in close association with the Ki67 PI (r =0.41; P < 0.0001). PKP-1+ and DP+ cells were correlated (0.32; P < 0.0001) and decreased from normal (81% versus 92.3%) to LSIL (53.1% versus 85.3%), to HSIL (46.4% versus 67.5%) and SCC (35.1% versus 35.9%). The Ki67+ PI was inversely correlated with DP (-0.20, P = 0.0014) and PKP-1 (-0.19, P = 0.015). Condylomata retained low CRBP-1 and high expression of PKP-1 and DP.

CONCLUSIONS

The gain of CRBP-1 and the loss of desmosomal proteins occur early in cervical carcinogenesis.

The pathology of endometriosis: a survey of the many faces of a common disease emphasizing diagnostic pitfalls and unusual and newly appreciated aspects

Although the histologic diagnosis of endometriosis is usually straightforward, many diagnostic problems can arise as a result of alterations or absence of its glandular or stromal components. The diagnostic difficulty in such cases can be compounded by tissue that is limited to a small biopsy specimen. The appearance of the glandular component can be altered by hormonal and metaplastic changes, as well as cytologic atypia and hyperplasia. Although the last 2 findings are often referred to collectively as "atypical endometriosis," they should be separately recognized as their premalignant potential likely differs. In some cases, the endometriotic glands are sparse or even absent (stromal endometriosis). The stromal component can be obscured or effaced by infiltrates of foamy and pigmented histiocytes, fibrosis, elastosis, smooth muscle metaplasia, myxoid change, and decidual change. Occasional findings in endometriosis that may raise concern for a neoplasm include necrotic pseudoxanthomatous nodules, polypoid growth (polypoid endometriosis), bulky disease, and venous, lymphatic, or perineural invasion. Inflammatory and reactive changes within, adjacent to, or at a distance from foci of endometriosis can complicate the histologic findings and include infection within endometriotic cysts, pseudoxanthomatous salpingitis, florid mesothelial hyperplasia, peritoneal inclusion cysts, and Liesegang rings. The histologic diagnosis of endometriosis can also be challenging when it involves an unusual or unexpected site. Five such site-specific problematic areas considered are endometriosis on or near the ovarian surface, superficial cervical endometriosis, vaginal endometriosis, tubal endometriosis, and intestinal endometriosis, including the important distinction of an endometrioid carcinoma arising from colonic endometriosis from a primary colonic adenocarcinoma. Finally, endometriotic foci can occasionally be intimately admixed with another process, such as peritoneal leiomyomatosis or gliomatosis, resulting in a potentially confusing histologic appearance.

Molecular profiling of experimental endometriosis identified gene expression patterns in common with human disease

OBJECTIVE

To validate a rat model of endometriosis using complimentary DNA (cDNA) microarrays by identifying common gene expression patterns between experimental and natural disease.

DESIGN

Autotransplantation rat model.

SETTING

Medical school department.

ANIMALS

Female Sprague-Dawley rats.

INTERVENTION(S)

Endometriosis was surgically induced by suturing uterine horn implants next to the small intestine's mesentery. Control rats received sutures with no implants. After 60 days, endometriotic implants and uterine horn were obtained.

MAIN OUTCOME MEASURE(S)

Gene expression levels determined by cDNA microarrays and real-time quantitative polymerase chain reaction (qPCR). The Cy5-labeled cDNA was synthesized from total RNA obtained from endometriotic implants. The Cy3-labeled cDNA was synthesized using uterine RNA from a control rat. Gene expression levels were analyzed after hybridizing experimental and control labeled cDNA to PIQOR (Parallel Identification and Quantification of RNAs) Toxicology Rat Microarrays (Miltenyi Biotec, Cologne, Germany) containing 1,252 known genes. The Cy5/Cy3 ratios were determined, and genes with >2-fold higher or <0.5-fold lower expression levels were selected. Microarray results were validated by QRT-PCR.

RESULT(S)

We observed differential expression of genes previously shown to be up-regulated in patients, including growth factors, inflammatory cytokines/receptors, tumor invasion/metastasis factors, adhesion molecules, and antiapoptotic factors.

CONCLUSION(S)

This study presents evidence in support of using this rat model to study the natural history of endometriosis and to test novel therapeutics for this incurable disease.

Cellular retinol binding protein-1 expression in endometrial hyperplasia and carcinoma: diagnostic and possible therapeutic implications

Cellular retinol binding protein-1 (CRBP-1) contributes to the maintenance of the differentiative state of endometrial glandular cells through the regulation of bioavailability of retinol and derivatives, but its role in endometrial oncogenetic process remains unclear. Antibodies to CRBP-1, estrogen and progesterone receptors (ER and PR) were applied to paraffin sections of proliferative (n = 10) and secretory endometrium (n = 9), and to endometrial polyps (n = 6), simple (n = 7), complex (n = 3) and atypical endometrial hyperplasias (n = 9) as well as to 47 endometrioid carcinomas of different histological grade (G) (G1, n = 18; G2, n = 19; G3, n = 10). Four serous and two clear cell carcinomas were also examined. In glandular cells, CRBP-1 positivity was mainly cytoplasmic and rarely in the nuclei. CRBP-1 immunodetection was weakly positive in proliferative and low and focal in secretory endometrium and higher in atypical as compared to simple and complex hyperplasias. CRBP-1 expression in G1 endometrioid carcinomas was similar to that in atypical hyperplasias. In the latter, the highest CRBP-1 expression was observed in areas of squamous differentiation. Semiquantitative evaluation revealed a significant decrease of cytoplasmic CRBP-1 immunoreactivity with the increase of tumor grade. Among G3 endometrioid carcinomas, 60% were CRBP-1 negative, whereas the remaining cases showed a very low and focal positivity. Serous carcinomas were also CRBP-1 negative. When areas of different grading were present within the same tumor, less differentiated areas retained a lower CRBP-1 immunoreaction. The progressive decrease of CRBP-1 paralleled that of ER and PR immunodetection. RT-PCR in eight endometrioid carcinomas suggested a decrease of CRBP-1 with the increase of tumor grade also at transcriptional level. Our results indicate that CRBP-1 immunodetection may constitute an additional tool for histological grading of endometrial carcinoma. The CRBP-1 loss during the progression of endometrial cancer suggests a new potential target for pharmacological strategies aimed to counteract its progression by increased intracellular retinol bioavailability.