MFG-E8 expression for progression of oral squamous cell carcinoma and for self-clearance of apoptotic cells

Potent CTLs can be induced against tumor cells in an environment of lower levels of systemic MFG-E8

The direction and magnitude of immune responses are critically affected when dead cells are disposed of. Milk fat globule-epidermal growth factor-factor 8 (MFG-E8) promotes the engulfment of apoptotic normal and cancerous cells without inducing inflammation. We have previously reported that a certain proportion of the cancer cells express abundant MFG-E8, and that such expression is associated with the shorter survival of patients with esophageal cancer who had received chemotherapy before surgery. However, the influence of tumor-derived and systemically existing MFG-E8 on antitumor immune responses has not yet been fully investigated. Herein, we showed that CTL-dependent antitumor immune responses were observed in mice with no or decreased levels of systemic MFG-E8, and that such responses were enhanced further with the administration of anti-PD-1 antibody. In mice with decreased levels of systemic MFG-E8, the dominance of regulatory T cells in tumor-infiltrating lymphocytes was inverted to CD8+ T cell dominance. MFG-E8 expression by tumor cells appears to affect antitumor immune responses only when the level of systemic MFG-E8 is lower than the physiological status. We have also demonstrated in the clinical setting that lower levels of plasma MFG-E8, but not MFG-E8 expression in tumor cells, before the treatment was associated with objective responses to anti-PD-1 therapy in patients with non-small cell lung cancer. These results suggest that systemic MFG-E8 plays a critical role during the immunological initiation process of antigen-presenting cells to increase tumor-specific CTLs. Regulation of the systemic level of MFG-E8 might induce efficient antitumor immune responses and enhance the potency of anti-PD-1 therapy.

Effects of MFG-E8 expression on the biological characteristics of ovarian cancer cells via the AKT/mTOR/S6K signalling pathway

In this study, we assessed the effects of MFG-E8 on the biological characteristics of ovarian cancer cells and explored the underlying mechanisms. Human ovarian cancer SKOV3 cells were transfected with MFG-E8 siRNA or NC siRNA. CCK-8, cell adhesion, scratch-wound, and Transwell assays were used to detect changes in cell metastatic processes. Effects of MFG-E8 silencing on the proteins involved in AKT/mTOR/S6K signalling pathway were assessed using qRT-PCR and Western blotting. Transient silencing of MFG-E8 in SKOV3 cells decreased cell proliferation and downregulated the expression of CDK4, cyclin D1, and caspase-3 proteins. Cell adhesion, migration, and invasion were also suppressed. p-AKT, p-mTORC1, and p-p70S6K levels decreased following MFG-E8 knockdown. Hence, MFG-E8 enhances carcinogenesis and affects the AKT/mTOR/S6K signalling pathway in ovarian cancer cells. In conclusion, our results suggested that MFG-E8 could promote ovarian cancer via AKT/mTOR/S6K signalling pathway which improved our understanding of the molecular mechanisms involved in ovarian cancer.IMPACT STATEMENTWhat is already known on this subject? Milk fat globule-epidermal growth factor 8 (MFG-E8) is expressed in several types of cancers such as oesophageal, breast, and liver. However, the mechanism of MFG-E8 involving in EOC remains unknown. We previously found that MFG-E8 expression was related to pathological staging, tissue differentiation, platinum sensitivity, ascites state, and other clinicopathological characteristics.What the results of this study add? Due to a series of in vitro studies, we confirmed that MFG-E8 is involved in the process of proliferation, invasion and metastasis. Our results show that silencing MFG-E8 can significantly inhibit the expression of cyclin D1 and CDK4 in EOC SKOV3 cells. MFG-E8 enhances carcinogenesis and affects the AKT/mTOR/S6K signaling pathway in ovarian cancer.What the implications are of these findings for clinical practice and/or further research? Taken together, our findings suggest that MFG-E8 may be an oncogene in EOC and provide new insights into the mechanism of MFG-E8 in the progression of EOC.

High Levels of MFG-E8 Confer a Good Prognosis in Prostate and Renal Cancer Patients

Simple Summary

In the present study, we analyzed the distribution and prognostic impact of milk fat globule-epidermal growth factor-8 (MFG-E8) protein expression in patients with prostate and renal cancers. Our data highlighted MFG-E8 expression by tumor cells in the epithelium. Our results also showed that low levels of MFG-E8 in prostate and renal cancers were associated with worse clinical outcomes. Furthermore, higher numbers of CD206⁺ cells were found in the peripheral regions of renal clear cell carcinoma that expressed lower MFG-E8 levels. Globally, our results suggest that MFG-E8 expression could potentially be used as a prognostic marker in prostate and renal cancers.

Abstract

Milk fat globule-epidermal growth factor-8 (MFG-E8) is a glycoprotein secreted by different cell types, including apoptotic cells and activated macrophages. MFG-E8 is highly expressed in a variety of cancers and is classically associated with tumor growth and poor patient prognosis through reprogramming of macrophages into the pro-tumoral/pro-angiogenic M2 phenotype. To date, correlations between levels of MFG-E8 and patient survival in prostate and renal cancers remain unclear. Here, we quantified MFG-E8 and CD68/CD206 expression by immunofluorescence staining in tissue microarrays constructed from renal (n = 190) and prostate (n = 274) cancer patient specimens. Percentages of MFG-E8-positive surface area were assessed in each patient core and Kaplan–Meier analyses were performed accordingly. We found that MFG-E8 was expressed more abundantly in malignant regions of prostate tissue and papillary renal cell carcinoma but was also increased in the normal adjacent regions in clear cell renal carcinoma. In addition, M2 tumor-associated macrophage staining was increased in the normal adjacent tissues compared to the malignant areas in renal cancer patients. Overall, high tissue expression of MFG-E8 was associated with less disease progression and better survival in prostate and renal cancer patients. Our observations provide new insights into tumoral MFG-E8 content and macrophage reprogramming in cancer.

Spindle cell squamous cell carcinoma exhibiting prominent neutrophil phagocytosis: a case report

Background

Spindle cell squamous cell carcinoma is an uncommon variant of squamous cell carcinoma; its diagnosis is sometimes challenging because it histopathologically resembles neoplastic or reactive spindle cell lesions of mesenchymal origins. Here, we report a rare case of spindle cell squamous cell carcinoma exhibiting prominent neutrophil phagocytosis.

Case presentation

A 69-year-old Japanese man presented with pain and a polypoid mass on the lower left gingiva. He had received chemoradiotherapy for squamous cell carcinoma of the buccal mucosa 15 years prior to this consultation. In addition, he was treated for mandibular osteonecrosis 6 years after chemoradiotherapy without evidence of cancer recurrence. A biopsy revealed atypical spindle or pleomorphic cells scattered in the edematous and fibrin-rich stroma; however, no malignant squamous components were apparent. These atypical cells frequently contained neutrophils within their cytoplasm that formed cell-in-cell figures. Immunohistochemically, the atypical cells were negative for cytokeratins, epithelial membrane antigen, and E-cadherin, but positive for p63, vimentin, and p53. Although these findings suggested spindle cell squamous cell carcinoma, it was difficult to reach a definitive diagnosis. Based on a clinical diagnosis of a malignant tumor, the patient underwent a hemimandibulectomy. The surgically resected specimen had a typical spindle cell squamous cell carcinoma histology consisting of biphasic spindle cells and conventional squamous cell carcinoma components. Moreover, the surgical specimen also exhibited spindle tumor cells that frequently included neutrophils, around which intense staining for lysosomal-associated membrane protein 1 and cathepsin B was observed. This suggested that the cell-in-cell figures represent active neutrophil phagocytosis by tumor cells, and not emperipolesis.

Conclusion

The presence of neutrophil phagocytosis may be a potent indicator of malignancy.

Rac1-dependent phagocytosis of apoptotic cells by oral squamous cell carcinoma cells: A possible driving force for tumor progression

Apoptotic cell death frequently occurs in human cancer tissues including oral squamous cell carcinoma (SCC), wherein apoptotic tumor cells are phagocytosed not only by macrophages but also by neighboring tumor cells. We previously reported that the engulfment of apoptotic SCC cells by neighboring SCC cells frequently occurs at the invading front. Therefore, we hypothesized that the phagocytosis of these apoptotic cells by tumor cells contributes to disease progression. Herein, using cultured oral SCC cells, we aimed to confirm whether tumor cells actually phagocytose apoptotic cells and to examine whether cellular activities are regulated by the phagocytosis of apoptotic cells. Co-culture experiments showed that living cells could ingest apoptotic cells into phagolysosomes. NSC23766, an inhibitor of Rac1, which is a key regulator of phagocytic cup formation in professional phagocytes, dramatically suppressed the phagocytosis of apoptotic cells by living cells. Additionally, cell migration and the secretion of DKK1, a tumor-promoting protein, were enhanced by co-culture with apoptotic cells, whereas NSC23766 inhibited these effects. These results show that tumor cells can actively phagocytose apoptotic neighbors in a Rac1-dependent manner and that such activity increases their migration. The regulation of apoptotic cell phagocytosis thus represents new directions for therapeutic intervention for oral cancer.

Milk Fat Globule-EGF Factor 8 Contributes to Progression of Hepatocellular Carcinoma

Milk fat globule-EGF factor 8 (MFG-E8) is an anti-inflammatory glycoprotein that mediates a wide spectrum of pathophysiological processes. MFG-E8 has been studied as a key regulator of cancer cell invasion, migration, and proliferation in different tissues and organs. However, potential roles of MFG-E8 in the growth and progression of liver cancer have not been investigated to date. Here, we analyzed 33 human hepatocellular carcinoma (HCC) samples and found that levels of MFG-E8 expression were significantly higher in HCC cells than in normal liver tissues. In addition, our in vitro gain-of-function study in three different HCC cell lines revealed that overexpression of MFG-E8 promoted the proliferation and migration of HCC cells, as determined by RT-qPCR, MTT assays, and wound healing analyses. Conversely, an MFG-E8 loss-of function study showed that proliferation capacity was significantly reduced by MFG-E8 knockdown in HCC cells. Additionally, MFG-E8 activity-neutralizing antibodies profoundly inhibited both migration and proliferation of HCC cells, attenuating their tumorigenic properties. These reductions in migration and proliferation were rescued by treatment of HCC cells with recombinant MFG-E8 protein. Furthermore, an in vivo HCC xenograft study showed that the number of proliferating HCC cells and tumor volume/weight were all significantly increased by MFG-E8 overexpression, compared to control mice. These results clearly show that MFG-E8 plays an important role in HCC progression and may provide a basis for future mechanistic studies and new strategies for the treatment of liver cancer.

The significance of tumor cells-derived MFG-E8 in tumor growth of angiosarcoma

BACKGROUND

Previous studies have indicated that MFG-E8 enhances tumor cell survival, invasion and angiogenesis. However, the role of MFG-E8 in angiosarcoma (AS) has not been clarified.

OBJECTIVE

Objective was to elucidate the mechanism of the regulation by MFG-E8 in AS and the association between MFG-E8 and clinicopathological features of AS.

METHODS

The effects of the depletion of MFG-E8 by siRNA on tube formation, migration and proliferation in murine AS cells were examined. The effect of administration of anti-MFG-E8 antibody (Ab) on tumor growth of AS in mice was examined. The associations of MFG-E8 expression and clinicopathological features of human AS were assessed.

RESULTS

The expressions of MFG-E8 in murine and human AS cells were significantly higher than those in melanoma cells, macrophages and endothelial cells. Depletion of MFG-E8 in murine AS cells by siRNA significantly inhibited the formation of capillary-like structures and migration, but not proliferation. Administration of anti-MFG-E8 Ab significantly inhibited tumor growth and decreased the number of tumor-associated macrophages (TAMs) in AS tumors. Tumor size and the number of TAMs in human AS with high expression of MFG-E8 were significantly increased compared to those of AS with low expression of MFG-E8. Progression-free survival and overall survival time of the patients of AS with high expression of MFG-E8 were significantly shorter than those of AS with low expression of MFG-E8.

CONCLUSIONS

AS-derived MFG-E8 might enhance tumor growth via angiogenesis and the induction of TAMs in autocrine/paracrine manner, and administration of anti-MFG-E8 Ab could be a therapeutic potential for AS.

Immunological and Clinicopathological Significance of MFG-E8 Expression in Patients with Oral Squamous Cell Carcinoma

Milk fat globule-epidermal growth factor 8 (MFG-E8) is a glycoprotein secreted by the activated macrophages and acts as a bridge between apoptotic cells and phagocytes. Aside from macrophages, a variety of malignant cells also express MFG-E8. The objective of this study is to elucidate the clinical relevance and significance of MFG-E8 in the tumor microenvironment (TME) of patients with oral squamous cell carcinoma (OSCC). We investigated MFG-E8 expression in 74 patients with OSCC by immunohistochemistry and evaluated the relationship between MFG-E8 expression and various clinicopathological factors including immune cell infiltration. MFG-E8 expression was detected in 34 of 74 (45.9%) patients with OSCC and a significant correlation was observed with levels of infiltrating T cells, macrophages, and immunosuppressive M2 macrophages. Furthermore, MFG-E8 expression was also associated with clinical stage, lymphatic/vascular invasion, and Ki-67+ tumor cells but not with survival. Our results suggest that MFG-E8 may play an important role in shaping the immune suppressive network in TME as well as tumor progression.

MFG-E8 overexpression is associated with poor prognosis in breast cancer patients

BACKGROUND

MFG-E8(Milk fat globule-EGF factor 8), a secreted glycoprotein, plays an exceptional role in various diseases. MFG-E8 overexpression is found in a variety of cancers. However, it remains unclear whether MFG-E8 overexpression is associated with the clinicopathological characteristics and prognosis of human breast cancer.

MATERIALS AND METHODS

In this study, we detected the expression and localization of MFG-E8 protein in breast cancer and cancer-adjacent tissues using immunohistochemical staining, Western blot analysis and immunofluorescence. We analyzed the association between MFG-E8 expression and clinical characteristics and outcomes of breast cancer patients with different HR and HER2 statuses.

RESULTS

Our results confirmed that MFG-E8 expression increased significantly in breast cancer compared with cancer-adjacent tissues by immunohistochemical staining (P <  0.001). Similarly, the Western blot results further confirmed the increased expression of MFG-E8 in breast cancer compared with cancer-adjacent tissues (P =  0.001). Immunofluorescence staining showed that MFG-E8 was mainly localized in the cytoplasm and membrane of tumor cells, consistent with the immunohistochemical staining results. The high expression levels of MFG-E8 showed a greater association with lymph node metastasis, TNM stage and histological grade (P < 0.001). Moreover, high MFG-E8 expression was related to a shortened overall survival (OS) (P <  0.001) and disease-free survival (DFS) (P <  0.001). Bioinformatics analysis with a Kaplan-Meier plotter also demonstrated a strong association of MFG-E8 mRNA overexpression with a short OS and DFS compared with low MFG-E8 expression (P =  0.040, P =  0.005).

CONCLUSIONS

Our findings indicate that MFG-E8 may be a potential marker for poor prognosis and survival in breast cancer.

Immunoregulatory influence of abundant MFG-E8 expression by esophageal cancer treated with chemotherapy

Milk fat globule‐epidermal growth factor factor 8 (MFG‐E8) is secreted from macrophages and is known to induce immunological tolerance mediated by regulatory T cells. However, the roles of the MFG‐E8 that is expressed by cancer cells have not yet been fully examined. Expression of MFG‐E8 was examined using immunohistochemistry in surgical samples from 134 patients with esophageal squamous cell carcinoma. The relationships between MFG‐E8 expression levels and clinicopathological factors, including tumor‐infiltrating lymphocytes, were evaluated. High MFG‐E8 expression was observed in 23.9% of the patients. The patients with tumors highly expressing MFG‐E8 had a significantly higher percentage of neoadjuvant chemotherapy (NAC) history (P < .0001) and shorter relapse‐free survival (P = 0.012) and overall survival (OS; P = .0047). On subgroup analysis, according to NAC history, patients with high MFG‐E8 expression had significantly shorter relapse‐free survival (P = .027) and OS (P = .0039) only when they had been treated with NAC. Furthermore, tumors with high MFG‐E8 expression had a significantly lower ratio of CD8⁺ T cells/regulatory T cells in tumor‐infiltrating lymphocytes (P = .042) only in the patients treated with NAC, and those with a lower ratio had a shorter OS (P = .026). High MFG‐E8 expression was also found to be an independent prognostic factor in multivariate analysis. The abundant MFG‐E8 expression in esophageal squamous cell carcinoma might have a negative influence on the long‐term survival of patients after chemotherapy by affecting T‐cell regulation in the tumor microenvironment.

Cytoplasmic expression of SOX9 as a poor prognostic factor for oral squamous cell carcinoma

Transcription factor SRY-box 9 (SOX9) is a key regulator of chondrocyte differentiation and sex determination, and it is also involved in the progression of various types of human cancer. However, its putative association with oral squamous cell carcinoma (OSCC) remains elusive. The aim of the present study was to investigate the expression profiles of SOX9 in various oral epithelial lesions, including OSCC. We performed immunohistochemical analysis of SOX9 expression in surgical specimens of OSCC, which simultaneously exhibited different grades of epithelial lesions, and analyzed the correlation between SOX9 expression and several clinicopathological factors. Moreover, we performed immunofluorescent staining, western blot analysis and real-time reverse transcription-polymerase chain reaction to assess SOX9 expression in OSCC HSC-3 (a metastatic cell line) and HSC-4 (a non-metastatic cell line) cell lines. In surgical specimens, SOX9 expression was detected in the nuclei of proliferating cells in areas with epithelial dysplasia and carcinoma in situ, but not in areas with normal epithelia. Nuclear SOX9 expression was observed in most SCC cells. Notably, cytoplasmic SOX9 expression was confirmed only in some SCC cells; however, cytoplasmic SOX9 expression was significantly and positively correlated with poor clinical outcomes. Both protein and mRNA expression of SOX9 were significantly higher in the HSC-3 cell line than that in the HSC-4 line. Notably, however, only HSC-3 cells exhibited cytoplasmic localization of SOX9 expression. Our findings indicate that SOX9 may be involved in the tumorigenesis and progression of OSCC. Furthermore, its cytoplasmic expression represents a potential predictive biomarker for tumor aggressiveness and OSCC prognosis.

Identification of Prognostic and Susceptibility Markers in Chronic Myeloid Leukemia Using Next Generation Sequencing

BACKGROUND

Incidence of Chronic Myeloid Leukemia (CML) is continuously increasing and expected to reach 100,000 patients every year by 2030. Though the discovery of Imatinib Mesylate (IM) has brought a paradigm shift in CML treatment, 20% patients show resistance to this tyrosine kinase inhibiter (TKI). Therefore, it is important to identify markers, which can predict the occurrence and prognosis of CML. Clinical Exome Sequencing, panel of more than 4800 genes, was performed in CML patients to identify prognostic and susceptibility markers in CML.

METHODS

Enrolled CML patients (n=18) were segregated as IM responders (n=10) and IM failures (n=8) as per European Leukemia Net (ELN), 2013 guidelines. Healthy controls (n=5) were also enrolled. DNA from blood of subjects was subjected to Next Generation Sequencing. Rare mutations present in one patient group and absent in another group were considered as prognostic markers, whereas mutations present in more than 50% patients were considered as susceptibility markers.

RESULT

Mutations in genes associated with cancer related functions were found in different patient groups. Four variants: rs116201358, rs4014596, rs52897880 and rs2274329 in C8A, UNC93B1, APOH and CA6 genes, respectively, were present in IM responders; whereas rs4945 in MFGE8 was present in IM failures. Mutations in HLA-DRB1 (rs17878951), HLA-DRB5 (rs137863146), RPHN2 (rs193179333), CYP2F1 (rs116958555), KCNJ12 (rs76684759) and FUT3 (rs151218854) were present as susceptibility markers.

CONCLUSION

The potential genetic markers discovered in this study can help in predicting response to IM as frontline therapy. Susceptibility markers may also be used as panel for individuals prone to have CML.

Prognostic Correlation Between MFG-E8 Expression Level and Colorectal Cancer

BACKGROUND AND AIMS

Colorectal cancer (CRC) is one of the leading causes of cancer-related death all over the world. Milk fat globule-epidermal growth factor (EGF)-factor VIII (MFG-E8) was found to be highly expressed in a variety of cancers. However its role in CRC is unclear. This study investigates the expression of MFG-E8 in CRC tissues and the correlation with clinicopathological features and prognosis in CRC patients.

METHODS

The expression of MFG-E8 proteins was detected by immunohistochemical staining in 90 samples of CRC. The localization of MFG-E8 in colorectal tumor was examined by immunofluorescence staining. The correlation between MFG-E8 protein expression and the clinical pathological features of CRC were evaluated by χ² test and Fisher's exact test. The survival rates were analyzed by the Kaplan-Meier method, and the relationship between prognostic factors and patient survival was analyzed by the Cox proportional hazard models.

RESULTS

Our results showed that MFG-E8 expression increased significantly in colorectal cancer compared with normal mucosa tissues (p <0.001). We further validated MFG-E8 overexpression in 6 pairs of fresh tumor and adjacent normal mucosa tissues from colorectal cancer patients by Western blot (p <0.05). Immunofluorescence staining showed that MFG-E8 accumulated in close proximity to endothelial cells in human colorectal tumor tissue. In addition, high MFG-E8 protein expression was correlated with lymph node metastasis and some pathological classifications (p <0.05). Furthermore, patients with high protein level of MFG-E8 showed shortened overall survivals (p <0.05).

CONCLUSION

Our results showed that MFG-E8 could be a potential novel prognostic marker for CRC and overexpression of MFG-E8 might be involved in lymph node metastasis and angiogenesis of CRC.

The relative contribution of DNA methylation and genetic variants on protein biomarkers for human diseases

Associations between epigenetic alterations and disease status have been identified for many diseases. However, there is no strong evidence that epigenetic alterations are directly causal for disease pathogenesis. In this study, we combined SNP and DNA methylation data with measurements of protein biomarkers for cancer, inflammation or cardiovascular disease, to investigate the relative contribution of genetic and epigenetic variation on biomarker levels. A total of 121 protein biomarkers were measured and analyzed in relation to DNA methylation at 470,000 genomic positions and to over 10 million SNPs. We performed epigenome-wide association study (EWAS) and genome-wide association study (GWAS) analyses, and integrated biomarker, DNA methylation and SNP data using between 698 and 1033 samples depending on data availability for the different analyses. We identified 124 and 45 loci (Bonferroni adjusted P < 0.05) with effect sizes up to 0.22 standard units' change per 1% change in DNA methylation levels and up to four standard units' change per copy of the effective allele in the EWAS and GWAS respectively. Most GWAS loci were cis-regulatory whereas most EWAS loci were located in trans. Eleven EWAS loci were associated with multiple biomarkers, including one in NLRC5 associated with CXCL11, CXCL9, IL-12, and IL-18 levels. All EWAS signals that overlapped with a GWAS locus were driven by underlying genetic variants and three EWAS signals were confounded by smoking. While some cis-regulatory SNPs for biomarkers appeared to have an effect also on DNA methylation levels, cis-regulatory SNPs for DNA methylation were not observed to affect biomarker levels. We present associations between protein biomarker and DNA methylation levels at numerous loci in the genome. The associations are likely to reflect the underlying pattern of genetic variants, specific environmental exposures, or represent secondary effects to the pathogenesis of disease.

miRNA in Macrophage Development and Function

SIGNIFICANCE

MicroRNAs (miRNAs) control cellular gene expression via primarily binding to 3' or 5' untranslated region of the target transcript leading to translational repression or mRNA degradation. In most cases, miRNAs have been observed to fine-tune the cellular responses and, therefore, act as a rheostat rather than an on/off switch. Transcription factor PU.1 is a master switch that controls monocyte/macrophage development from hematopoietic stem cells. Recent Advances: PU.1 induces a specific set of miRNAs while suppressing the miR17-92 cluster to regulate monocyte/macrophage development. In addition to development, miRNAs tightly control the macrophage polarization continuum from proinflammatory M1 or proreparative M2 by regulating expression of key transcription factors involved in the process of polarization.

CRITICAL ISSUES

miRNAs are intricately involved with fine-tuning fundamental macrophage functions such as phagocytosis, efferocytosis, inflammation, tissue repair, and tumor promotion. Macrophages are secretory cells that participate in intercellular communication by releasing regulatory molecules and microvesicles (MVs). MVs are bilayered lipid membranes packaging a hydrophilic cargo, including proteins and nucleic acids. Macrophage-derived MVs carry functionally active miRNAs that suppress gene expression in target cells via post-transcriptional gene silencing, thus regulating cell function. In summary, miRNAs fine-tune several major facets of macrophage development and function. Such fine-tuning is critical in preventing exaggerated macrophage response to endogenous or exogenous stimuli.

FUTURE DIRECTIONS

A critical role of miRNAs in the regulation of innate immune response and macrophage biology, including development, differentiation, and activation, has emerged. A clear understanding of such regulation on macrophage function remains to be elucidated. Antioxid. Redox Signal. 25, 795-804.

Aberrant expression of the tight junction molecules claudin-1 and zonula occludens-1 mediates cell growth and invasion in oral squamous cell carcinoma

We reported that altered cell contact mediated by E-cadherin is an initial event in the pathogenesis of oral epithelial malignancies. To assess other effects of cell adhesion, we examined the expression levels of tight junction (TJ) molecules in oral carcinoma in situ (CIS) and squamous cell carcinoma (SCC). To identify changes in the expression of TJ molecules, we conducted an analysis of the immunohistochemical profiles of claudin-1 (CLDN-1) and zonula occludens-1 (ZO-1) in surgical specimens acquired from patients with oral SCC containing foci of epithelial dysplasia or from patients with CIS. We used immunofluorescence, Western blotting, reverse-transcription polymerase chain reaction, and RNA interference to evaluate the functions of CLDN-1 and ZO-1 in cultured oral SCC cells. TJ molecules were not detected in normal oral epithelial tissues but were expressed in SCC/CIS cells. ZO-1 was localized within the nucleus of proliferating cells. When CLDN-1 expression was inhibited by transfecting cells with specific small interference RNAs, SCC cells dissociated, and their ability to proliferate and invade Matrigel was inhibited. In contrast, although RNA interference-mediated inhibition of ZO-1 expression did not affect cell morphology, it inhibited cell proliferation and invasiveness. Our findings indicated that the detection of TJ molecules in the oral epithelia may serve as a marker for the malignant phenotype of cells in which CLDN-1 regulates proliferation and invasion.

Correction of MFG-E8 Resolves Inflammation and Promotes Cutaneous Wound Healing in Diabetes

Milk fat globule epidermal growth factor-factor 8 (MFG-E8) is a peripheral glycoprotein that acts as a bridging molecule between the macrophage and apoptotic cells, thus executing a pivotal role in the scavenging of apoptotic cells from affected tissue. We have previously reported that apoptotic cell clearance activity or efferocytosis is compromised in diabetic wound macrophages. In this work, we test the hypothesis that MFG-E8 helps resolve inflammation, supports angiogenesis, and accelerates wound closure. MFG-E8(-/-) mice displayed impaired efferocytosis associated with exaggerated inflammatory response, poor angiogenesis, and wound closure. Wound macrophage-derived MFG-E8 was recognized as a critical driver of wound angiogenesis. Transplantation of MFG-E8(-/-) bone marrow to MFG-E8(+/+) mice resulted in impaired wound closure and compromised wound vascularization. In contrast, MFG-E8(-/-) mice that received wild-type bone marrow showed improved wound closure and improved wound vascularization. Hyperglycemia and exposure to advanced glycated end products inactivated MFG-E8, recognizing a key mechanism that complicates diabetic wound healing. Diabetic db/db mice suffered from impaired efferocytosis accompanied with persistent inflammation and slow wound closure. Topical recombinant MFG-E8 induced resolution of wound inflammation, improvements in angiogenesis, and acceleration of closure, upholding the potential of MFG-E8-directed therapeutics in diabetic wound care.

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.