Modulation of L-Arginine-Arginase Metabolic Pathway Enzymes: Immunocytochemistry and mRNA Expression in Peripheral Blood and Tissue Levels in Head and Neck Squamous Cell Carcinomas in North East India

Abstract

Background: Arginine may play important roles in tumor progression by providing ornithine for polyamine biosynthesis, required for cell growth. The aim of this work was to determine the expression of arginine metabolic pathway enzymes in head and neck squamous cell carcinoma (HNSCC) in northeast India. Materials and Methods: The expressions of arginase isoforms (ARG1 and ARG2), ornithine aminotransferase (OAT) and ornithine decarboxylase (ODC) were examined in fifty paired HNSCC and adjacent non-tumor tissues by immunohistochemistry. Immunocytochemistry, semiquantitative reverse transcription sq-PCR and quantitative real-time qPCR were used to assess protein and mRNA expressions in peripheral blood of fifty HNSCC patients and hundred controls. Results: ARG1 and ODC protein and mRNA were strongly expressed in peripheral blood from HNSCC patients. No ARG2 expression was observed. In vivo, expression of ARG1, ARG2 and ODC was significantly higher in tumor than in non-tumor tissues. Most tumors expressed low levels of OAT, with no difference in tissues or blood, compared to controls. The absolute extent of maximal ARG1 upregulation with qPCR showed 6.23 fold increase in HNSCC. Conclusions: These findings strongly suggest that in HNSCCs, the ARG1 pathway is stimulated leading to the formation of polyamines as indicated by higher ODC expression, which promote tumor growth.

ARG1 mRNA Level Is a Promising Prognostic Marker in Head and Neck Squamous Cell Carcinomas

“…Similar results were observed in patients with colorectal cancer, where a higher ARG1 mRNA level was associated with worse OS and disease-free survival (DFS) [62], or classic Hodgkin lymphoma, where an elevated level of ARG1 negatively influenced PFS [37]. The overexpression of ARG1 in HNSCC tissue and peripheral blood compared to healthy donors was described by Shrivastava et al [63], but opposite results were shown by Ohashi et al [57]. Both studies did not address tumor etiology or prognosis, which may explain the discrepancy of the results.…”

The Role of Arginine Metabolism in Oral Tongue Squamous Cell Carcinoma

“…Firstly, we show that ARG1, the enzyme responsible for the catabolism of arginine, is not expressed by oral tongue cancer cells. Although this contradicts one previous study [ 12 ], it corroborates various other findings [ 13 , 14 , 15 ] and supports the hypothesis that arginine metabolism is selectively rewired in oral tongue cancer cells to create a survival advantage. Considering the lack of expression of ARG1 , we next sought to determine whether oral tongue cancer cells had adapted to function and proliferate without relying on arginine catabolism.…”

“…Aggregated results from one previous report hinted that ARG1 protein expression was higher in head and neck tumor tissues compared with nontumor [ 12 ]. However, these findings are opposite to our more recently published data [ 13 ] and two independent datasets (GEO (U133Plus2 GPL570) and TCGA) ( Figure 1 a) [ 14 , 15 ].…”

“…The total number of clean reads ranged from 19.6 M to 22.3 M across all six samples, with a fraction of Q30 bases >93.5% in each sample. We mapped the resulting quality-filtered reads to human genome using HISAT2 (v2.0.4) [ 12 ] with prebuilt indexes based on the GRCh38 reference assembly. The generated SAM files were converted to BAM files and sorted using SAMtools (v1.5) [ 13 ].…”

Large-Scale Tissue Microarray Evaluation Corroborates High Specificity of High-Level Arginase-1 Immunostaining for Hepatocellular Carcinoma

“…Because arginase-1 expression is usually retained in hepatocellular carcinoma, a cancer derived from hepatocytes, the immunohistochemical detection of arginase expression is commonly used to support the difficult distinction of hepatocellular carcinoma from cholangiocellular carcinoma and metastases to the liver [ 5 ]. This procedure is supported by more than 20 studies demonstrating arginase-1 expression in 80–100% of hepatocellular carcinomas [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ].…”