Differentiation and roles of bone marrow-derived cells on the tumor microenvironment of oral squamous cell carcinoma

Cancer-Associated Stromal Cells Promote the Contribution of MMP2-Positive Bone Marrow-Derived Cells to Oral Squamous Cell Carcinoma Invasion

Simple Summary

Based on its invasiveness, oral squamous cell carcinoma (OSCC) shows two different subtypes: less-invasive verrucous squamous carcinoma (VSCC) or highly invasive squamous cell carcinoma (SCC). The stromal component influences OSCC progression and invasion. On the other hand, bone marrow-derived cells (BMDCs) are recruited into tumors and involved in tumor development. We hypothesized that stromal factors might also affect the relation of BMDCs and tumor invasion. We established the OSCC models transplanted with stromal cells from VSCC and SCC, and we compared the potential stromal factors of VSCC and SCC for the involvement of BMDCs in tumor invasion. Our study showed that stromal factors IL6 and IL1B might promote the contribution of MMP-2 positive BMDCs to OSCC invasion.

Abstract

Tumor stromal components contribute to tumor development and invasion. However, the role of stromal cells in the contribution of bone marrow-derived cells (BMDCs) in oral squamous cell carcinoma (OSCC) invasion is unclear. In the present study, we created two different invasive OSCC patient-derived stroma xenografts (PDSXs) and analyzed and compared the effects of stromal cells on the relation of BMDCs and tumor invasion. We isolated stromal cells from two OSCC patients: less invasive verrucous OSCC (VSCC) and highly invasive conventional OSCC (SCC) and co-xenografted with the OSCC cell line (HSC-2) on green fluorescent protein (GFP)-positive bone marrow (BM) cells transplanted mice. We traced the GFP-positive BM cells by immunohistochemistry (IHC) and detected matrix metalloproteinase 2 (MMP2) expression on BM cells by double fluorescent IHC. The results indicated that the SCC-PDSX promotes MMP2-positive BMDCs recruitment to the invasive front line of the tumor. Furthermore, microarray analysis revealed that the expressions of interleukin 6; IL-6 mRNA and interleukin 1 beta; IL1B mRNA were higher in SCC stromal cells than in VSCC stromal cells. Thus, our study first reports that IL-6 and IL1B might be the potential stromal factors promoting the contribution of MMP2-positive BMDCs to OSCC invasion.

Dual Role of p73 in Cancer Microenvironment and DNA Damage Response

Understanding the mechanisms that regulate cancer progression is pivotal for the development of new therapies. Although p53 is mutated in half of human cancers, its family member p73 is not. At the same time, isoforms of p73 are often overexpressed in cancers and p73 can overtake many p53 functions to kill abnormal cells. According to the latest studies, while p73 represses epithelial–mesenchymal transition and metastasis, it can also promote tumour growth by modulating crosstalk between cancer and immune cells in the tumor microenvironment, M2 macrophage polarisation, Th2 T-cell differentiation, and angiogenesis. Thus, p73 likely plays a dual role as a tumor suppressor by regulating apoptosis in response to genotoxic stress or as an oncoprotein by promoting the immunosuppressive environment and immune cell differentiation.

Hepatoma Cell-Derived Extracellular Vesicles Promote Liver Cancer Metastasis by Inducing the Differentiation of Bone Marrow Stem Cells Through microRNA-181d-5p and the FAK/Src Pathway

Bone marrow mesenchymal stem cells (BMSCs) are beneficial to repair the damaged liver. Tumor-derived extracellular vesicles (EV) are notorious in tumor metastasis. But the mechanism underlying hepatoma cell-derived EVs in BMSCs and liver cancer remains unclear. We hypothesize that hepatoma cell-derived EVs compromise the effects of BMSCs on the metastasis of liver cancer. The differentially expressed microRNAs (miRNAs) were screened. HepG2 cells were transfected with miR-181d-5p mimic or inhibitor, and the EVs were isolated and incubated with BMSCs to evaluate the differentiation of BMSCs into fibroblasts. Hepatoma cells were cultured with BMSCs conditioned medium (CM) treated with HepG2-EVs to assess the malignant behaviors of hepatoma cells. The downstream genes and pathways of miR-181d-5p were analyzed and their involvement in the effect of EVs on BMSC differentiation was verified through functional rescue experiments. The nude mice were transplanted with BMSCs-CM or BMSCs-CM treated with HepG2-EVs, and then tumor growth and metastasis in vivo were assessed. HepG2-EVs promoted fibroblastic differentiation of BMSCs, and elevated levels of α-SMA, vimentin, and collagen in BMSCs. BMSCs-CM treated with HepG2-EVs stimulated the proliferation, migration, invasion and epithelial-mesenchymal-transition (EMT) of hepatoma cells. miR-181d-5p was the most upregulated in HepG2-EVs-treated BMSCs. miR-181d-5p targeted SOCS3 to activate the FAK/Src pathway and SOCS3 overexpression inactivated the FAK/Src pathway. Reduction of miR-181d-5p in HepG2-EVs or SOCS3 overexpression reduced the differentiation of BMSCs into fibroblasts, and compromised the promoting effect of HepG2-EVs-treated BMSCs-CM on hepatoma cells. In vivo, HepG2-EVs-treated BMSCs facilitated liver cancer growth and metastasis. In conclusion, HepG2-EVs promote the differentiation of BMSCs, and promote liver cancer metastasis through the delivery of miR-181d-5p and the SOCS3/FAK/Src pathway.