Metallothioneins and Megalin Expression Profiling in Premalignant and Malignant Oral Squamous Epithelial Lesions

Abstract

This study aimed to assess the relationship and possible interactions between metallothioneins (MTs) and megalin (LRP-2) in different grades of oral squamous cell carcinoma (OSCC) and premalignant lesions of the oral mucosa (oral leukoplakia and oral lichen planus). The study included archived samples of 114 patients and control subjects. Protein expression was examined by immunohistochemistry and immunofluorescence, and staining quantification was performed by ImageJ software. Protein interaction in cancer tissue was tested and visualized by proximity ligation assay. Mann-Whitney and Kruskal-Wallis tests were used to determine the significance of differences between each group, whereas Pearson correlation coefficient was performed to test correlation. Expression of both proteins differed significantly between each group showing the same pattern of gradual increasing from oral lichen planus to poorly differentiated OSCC. Moreover, MTs and megalin were found to co-express and interact in cancer tissue, and their expression positively correlated within the overall study group. Findings of prominent nuclear and chromosomal megalin expression suggest that it undergoes regulated intramembrane proteolysis upon MTs binding, indicating its ability to directly affect gene expression and cellular division in cancer tissue. The data obtained point to the onco-driving potential of MTs-megalin interaction.

Megalin Expression in Primary Oral Squamous Cell Carcinoma Is Associated With the Presence of Lymph Node Metastases, Vascular Invasion and Lower Overall Survival

“…We are obliged to mention here that we used an anti-megalin antibody recognizing epitopes situated at the megalin intracellular domain (H-245, Santa Cruz Biotechnology, USA). Recently, we also demonstrated chromosomal expression of megalin in cancer cells with mitotic figures, which points to the immediate involvement of megalin in the cellular division process [16]. That finding, together with the currently presented co-expression of PCNA and megalin in cancer cells (Figure 2), underlines the proproliferative role of the molecule concerned.…”

“…Despite megalin may, owing to its receptor versatility and ability to trigger gene-modulating signaling pathways [9], promote oncogenesis and tumor progression, research on its role in cancer pathobiology has been somewhat neglected so far. Only several studies have linked megalin with malignant transformation, and literature data offering possible mechanistic insights almost completely lacking [15,16,[19][20][21]. Pedersen et al showed acquisition of megalin expression in brain non-Hodgkinlymphoma [20], while Schuetz and colleagues found that clear cell renal cell carcinoma overexpressed megalin [21].…”

“…Though the presence of megalin expression may promote tumor growth and invasiveness by two principal ways, by supplying cells with increasingly needed metabolites and by modulating gene expression [9,10,11], megalin has been understudied in the field of molecular oncology so far, and only a few studies emphasized its oncodriving potential [12,13,14,15]. Recently, we showed that cancer tissue obtained from OSCC patients gradually overexpresses megalin depending on the tumor cell differentiation [16]. In an effort to expand insights on that topic, in the present study we aimed to assess if clinicopathological features and survival of patients with OSCC are related to megalin expression, assuming it as a possible predictive marker.…”

Multiplex Tissue Imaging: Spatial Revelations in the Tumor Microenvironment

“…In recent years, the development of multiplex imaging technologies has increased the need for methods to analyze imaging data, particularly spatial single-cell analysis. Im-ageJ [86] is the major open-source software package used for many different image analysis tasks, including single-cell segmentation, tumor grading of clinical images originating from magnetic resonance imaging (MRI), or staining quantification [87][88][89]. A more recent open-source software package specifically developed for tissue analysis, QuPath [90], is now being applied to multiple spatial tissue analysis tasks, including region annotation, cell segmentation, marker expression, and distance calculation.…”

H3K36M provokes cellular plasticity to drive aberrant glandular formation and squamous carcinogenesis

“…Likewise, S100a8 and S100a9 have also been shown to be upregulated in SCC 37 . Interestingly, metallothionein 3 ( Mt3 ) was the most significantly upregulated gene in our dataset and it has been noted to be highly expressed in both SCC 38 , as well as in the salivary gland 39 . Together, these data show that the in vivo presence of H3K36M in the oral epithelium causes widespread transcriptional alterations that are marked by a significant loss of differentiation genes along with a striking concomitant upregulation of genes typically expressed in salivary and glandular tissues, as well as genes frequently overexpressed in HNSCC.…”