Tumour-associated macrophages are recruited and differentiated in the neoplastic stroma of oral squamous cell carcinoma.

To confirm our hypothesis that macrophages recruited to fight against oral squamous cell carcinoma (SCC) invasion are functionally differentiated within neoplastic stromata, we analysed arrangements of macrophage subtypes and cancer-associated fibroblasts (CAFs) in their association with blood vasculatures in the neoplastic stroma. Surgical specimens of oral SCC were immunohistochemically examined for macrophage phenotypes (CD68, CD163, and CD204) and stromal environments (perlecan, connexin 43, and CD31). Human monocytes were co-cultured with ZK-1 cells of oral SCC origin in different culture conditions. SCC stromata were divided into two types: fascicular (fibroblast-rich) and reticular (perlecan-rich). Regardless of stromal types, CD68 positive (+)/CD163+/CD204+ macrophages were recruited when blood vessels were abundant. Connexin 43+ fibroblasts were enriched in the fascicular stroma, where blood vessels were depleted. In co-culture experiments, monocytes, in the presence of ZK-1 cells, showed TNF-α(low)/IL-12(low) and IL-10(high)/VEGF(high)/MMP-9(high) with increased expression levels for fibronectin and perlecan. With direct contact with monocytes, SCC cells also expressed CD68 and CD163. SCC stromata were characterised by CD163+/CD204+ tumour-associated macrophages (TAMs) and connexin 43+ CAFs. TAMs are differentiated from monocytes by the physical contact with oral SCC cells in the perlecan-rich neoplastic stroma, which is also induced by the cross-talk between SCC cells and stromal cells including TAMs.

Essa AA ，Yamazaki M ，Maruyama S ，Abé T ，Babkair H ，Raghib AM ，Megahed EM ，Cheng J ，Saku T ... -  《-》

CD163(+)CD204(+) tumor-associated macrophages contribute to T cell regulation via interleukin-10 and PD-L1 production in oral squamous cell carcinoma.

Kubota K ，Moriyama M ，Furukawa S ，Rafiul HASM ，Maruse Y ，Jinno T ，Tanaka A ，Ohta M ，Ishiguro N ，Yamauchi M ，Sakamoto M ，Maehara T ，Hayashida JN ，Kawano S ，Kiyoshima T ，Nakamura S ... -  《Scientific Reports》

Cancer-associated fibroblasts and CD163-positive macrophages in oral squamous cell carcinoma: their clinicopathological and prognostic significance.

Stromal cells are believed to affect cancer invasion and metastasis. The purpose of this study was to evaluate the distribution of cancer-associated fibroblasts (CAFs) and the incidence of tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC), focusing on clinicopathological factors and patient prognosis, as well as cancer invasion. The study included 108 patients with OSCC. Anti-α-smooth muscle actin, CD68, and CD163 antibodies were used to identify CAFs and TAMs. CAFs were divided into 4 grades on the basis of staining intensity: negative (0), scanty (1), focal (2), and abundant (3). The most intensive areas of macrophage concentration in each tumor invasive stroma were also evaluated. The cancer specimens were divided into Grade 0/1, Grade 2, and Grade 3 on the basis of CAF grade. In addition, they were divided into low- and high-grade groups on the basis of the number of CD68-positive and CD163-positive macrophages. The latter were significantly increased in the Grade 2 CAF group compared to the Grade 0/1 group (P = 0.009). Kaplan-Meier and multivariate survival analyses revealed that Grade 2 CAFs (P = 0.003) and high CD163-positive macrophage levels (P = 0.007) significantly correlated with a poor outcome in patients with OSCC, and that a high CD163-positive macrophage level was a significant and an independent prognostic factor (P = 0.045). Cancer-associated fibroblasts and CD163-positive macrophages may be potential prognostic predictors of OSCC.

Fujii N ，Shomori K ，Shiomi T ，Nakabayashi M ，Takeda C ，Ryoke K ，Ito H ... -  《-》

Keratin pearl degradation in oral squamous cell carcinoma: reciprocal roles of neutrophils and macrophages.

We have reported that neutrophilic infiltration was associated with round-shaped dyskeratosis foci, a kind of keratin pearl, of oral carcinoma in situ and that those inflammatory cells are recruited from intra-epithelially entrapped blood vessels. Based on these lines of evidence, we have formulated a hypothesis that keratin pearls are terminally degraded by neutrophils. To confirm this hypothesis, we investigated immunohistochemically stepwise degradation of keratin pearls in oral squamous cell carcinoma (SCC) to clarify any other type scavenger cells in addition to neutrophils are involved in this particular degradation process. Neutrophils (neutrophil elastase) and macrophage subpopulations (CD68, CD163 and CD204) were immunohistochemically localized in 30 cases of oral SCC with typical round-shaped keratin pearls. SCC cells were revealed by immunohistochemistry for keratin (K) 17, and blood vessels were demonstrated by CD31. Keratin pearl degradation process was divided into four steps: (i) intact stage: no macrophage infiltration but minimal neutrophils were found in keratin pearls; (ii) neutrophil recruit stage: no macrophage infiltration but focal neutrophilic infiltration within the pearls; (iii) neutrophil predominant stage: dense neutrophil infiltration with minimal macrophages and segregated keratinized cancer cells strongly positive for K17; and (iv) macrophage predominant stage: dense infiltration of CD68-, CD163 (mononuclear)- and CD204 (multinucleated)-positive macrophages engulfing detached keratinized SCC cells. Keratin pearl degradation in oral SCC is strictly regulated by two types of scavenger cells: neutrophils, which perform initial tasks, and macrophages, which reciprocally take over from neutrophils the role to finalize the degradation processes.

Essa AA ，Yamazaki M ，Maruyama S ，Abé T ，Babkair H ，Cheng J ，Saku T ... -  《-》

Parenchymal-stromal switching for extracellular matrix production on invasion of oral squamous cell carcinoma.

It is poorly understood which cell type, tumor cells, or stromal cells are responsible for the production of extracellular matrix molecules in the neoplastic stroma. We studied the expression of 4 extracellular matrix molecules at the protein and messenger RNA levels in monocellular and 2 kinds of coculture systems between human squamous cell carcinoma (ZK-1) and fibroblast (OF-1) cell lines, which may correspond to carcinoma in situ and squamous cell carcinoma, respectively. Squamous cell carcinoma and carcinoma in situ tissue sections were also investigated by immunohistochemistry and in situ hybridization for extracellular matrix. Immunohistochemically, perlecan and tenascin C were localized in carcinoma cells in carcinoma in situ, whereas they were in the stromal space in squamous cell carcinoma. In monocellular culture conditions, expression levels for perlecan, tenascin C, and laminin were more predominant in ZK-1 than in OF-1, although those for fibronectin were more enhanced in OF-1. However, these extracellular matrix expression levels of OF-1 were elevated, whereas those of ZK-1 dropped when they were in coculture conditions. The differences between ZK-1 and OF-1 were significantly more evident in direct contact (ZK-1/OF-1, 56%-22%) than in indirect contact (63%-39%). These results indicate that oral squamous cell carcinoma cells produce extracellular matrix in the absence of stromal fibroblasts (or in carcinoma in situ) and that they stop producing extracellular matrix in the presence of fibroblasts (or in squamous cell carcinoma). It is hence suggested that stromal fibroblasts after direct contact with invading squamous cell carcinoma cells are more responsible than squamous cell carcinoma cells for the formation of neoplastic stroma, whereas carcinoma in situ cells have to produce and deposit extracellular matrix by themselves to form intraepithelial microstromal spaces.

Metwaly H ，Maruyama S ，Yamazaki M ，Tsuneki M ，Abé T ，Jen KY ，Cheng J ，Saku T ... -  《-》