Label-Free Infrared Spectral Histology of Skin Tissue Part II: Impact of a Lumican-Derived Peptide on Melanoma Growth.

Stéphane Brézillon,Hossam Taha Mohamed,Estelle Ahallal,Camille Boulagnon-Rombi,Ganesh D Sockalingum,Valérie Untereiner,Pierre Nizet,Isabelle Proult

doi:10.3389/fcell.2020.00377

Abstract

Melanoma is the most aggressive type of cutaneous malignancies. In addition to its role as a regulator of extracellular matrix (ECM) integrity, lumican, a small leucine-rich proteoglycan, also exhibits anti-tumor properties in melanoma. This work focuses on the use of infrared spectral imaging (IRSI) and histopathology (IRSH) to study the effect of lumican-derived peptide (L9Mc) on B16F1 melanoma primary tumor growth. Female C57BL/6 mice were injected with B16F1 cells treated with L9Mc (n = 10) or its scrambled peptide (n = 8), and without peptide (control, n = 9). The melanoma primary tumors were subjected to histological and IR imaging analysis. In addition, immunohistochemical staining was performed using anti-Ki-67 and anti-cleaved caspase-3 antibodies. The IR images were analyzed by common K-means clustering to obtain high-contrast IRSH that allowed identifying different ECM tissue regions from the epidermis to the tumor area, which correlated well with H&E staining. Furthermore, IRSH showed good correlation with immunostaining data obtained with anti-Ki-67 and anti-cleaved caspase-3 antibodies, whereby the L9Mc peptide inhibited cell proliferation and increased strongly apoptosis of B16F1 cells in this mouse model of melanoma primary tumors.

Highlights

Melanoma is the most aggressive and deadliest form of skin cancers representing 80% of deaths in cutaneous malignancies (Miller and Mihm, 2006; Hodi et al, 2010)
The biological changes occurring in the primary tumor that lead to metastatic tumors including loss of adherent junctions, extracellular matrix (ECM) degradation, increased carcinoma cells motility and resistance to apoptosis, are better understood
Hematoxylin and Eosin solution (H&E) staining of representative sections of each group are shown in Figures 2A, 3A,F, respectively, and at a higher magnification (2.5x, 10x, and 15x) in Supplementary Figure 1 with the corresponding Crosscope links

Summary

Introduction

Melanoma is the most aggressive and deadliest form of skin cancers representing 80% of deaths in cutaneous malignancies (Miller and Mihm, 2006; Hodi et al, 2010). Treatment of metastatic melanoma is a health issue due to resistance to most available therapies and low survival rates (Soengas and Lowe, 2003; GraySchopfer et al, 2007; Greene and Sobin, 2008). Anticancer strategies developed over the last years, focused on understanding the cross-talk between malignant cells (Valkenburg et al, 2018; Liu et al, 2019) and the tumor microenvironment including both stromal cells and ECM (Belotti et al, 2011; Venning et al, 2015) such as targeting matricellular proteins, that regulate the communication between ECM and cancer cells (Wong and Rustgi, 2013)

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