Laminin C1 expression by uterine carcinoma cells is associated with tumor progression

Abstract

Objectives: Molecular markers associated with tumor progression in uterine carcinoma are poorly defined. In this study, we determine whether upregulation of LAMC1, a gene encoding extracellular matrix protein, laminin γ1, is associated with various uterine carcinoma subtypes and stages of tumor progression.

Methods: An analysis of the immunostaining patterns of laminin γ1 in normal endometrium, atypical hyperplasia, and a total of 150 uterine carcinomas, including low-grade and high-grade endometrioid carcinomas, uterine serous and clear cell carcinoma, was performed. Clinicopathological correlation was performed to determine biological significance. The Cancer Genome Atlas (TCGA) data set was used to validate our results.

Results: As compared to normal proliferative and secretory endometrium, for which laminin γ1 immunoreactivity was almost undetectable, increasing laminin C1 staining intensity was observed in epithelial cells from atypical hyperplasia to low-grade endometrioid to high-grade endometrioid carcinoma, respectively. Laminin γ1 expression was significantly associated with FIGO stage, myometrial invasion, cervical/adnexal involvement, angiolymphatic invasion and lymph node metastasis. Similarly, analysis of the endometrial carcinoma data set from TCGA revealed that LAMC1 transcript levels were higher in high-grade than those in low-grade endometrioid carcinoma. Silencing LAMC1 expression by siRNAs in a high-grade endometrioid carcinoma cell line did not affect its proliferative activity but significantly suppressed cell motility and invasion in vitro.

Conclusions: These data suggest that laminin γ1 may contribute to the development and progression of uterine carcinoma, likely through enhancing tumor cell motility and invasion. Laminin γ1 warrants further investigation regarding its role as a biomarker and therapeutic target in uterine carcinoma.

Keywords: Endometrial carcinoma; Laminin; Pathogenesis; Pathology; Uterine carcinoma.

Fig 1

LAMC1 mRNA expression in the data set from TCGA uterine corpus carcinoma. A Comparison of LAMC1 mRNA expression in different grades of endometrioid carcinomas. Grade 3 (Gr 3) carcinomas have significantly higher expression levels than grade 1 (Gr 1). B. LAMC1 mRNA levels are higher in uterine serous carcinomas than those in endometrioid carcinomas (all grades combined).

Fig 2

Laminin γ1 protein expression as assessed by immunohistochemistry and using the H-score system in normal endometrium and different grades and types of uterine carcinomas. The H-scores are higher in carcinoma tissues than normal proliferative endometrium [PEM), secretory endometrium (SEM) and atypical hyperplasia (AH) tissues. Endometrioid grade 3 carcinomas (EMG3) have higher H-scores than grade 1 tumors [EMG1). The results of statistical analyses of group comparison are listed.

Fig. 3

Laminin γ1 immunoreactivity in representative samples of normal and neoplastic tissues. All images were captured at the same magnification. EMC: endometrioid carcinoma; Gn grade.

Fig. 4

Result of laminin γ1 protein levels (as reflected by H-scores) in relation to clinicopathological parameters in endometrioid carcinoma. LVSI: lymph-vascular space invasion; LN meta: regional lymph node metastasis. +: present; –: absent.

Fig. 5

The effects of LAMC1 knockdown by siRNAs on cellular proliferation, motility and invasion in HEC1B cells. A: LAMC1 mRNA is significantly decreased by either siRNAs targeting LAMC1. B: LAMC1 protein (laminin γ1) is significantly reduced after gene knockdown by both siRNAs as compared to mock transfection control and transfection with control siRNA. C Cellular proliferation is not affected by LAMC1 targeting siRNAs (blue and black lines) as compared to mock (red line) and control siRNA (green line) groups. D. Motility assay shows reduced LAMC1 expression by siRNAs reduces cellular motility. E. Both LAMC1 targeting siRNAs suppress cellular invasion as compared to control siRNA treated cells.