Squamous cell carcinoma of skin: a brief review

The role of EphA7 in different tumors

Ephrin receptor A7 (EphA7) is a member of the Eph receptor family. It is widely involved in signal transduction between cells, regulates cell proliferation and differentiation, and participates in developing neural tubes and brain. In addition, EphA7 also has a dual role of tumor promoter and tumor suppressor. It can participate in cell proliferation, migration and apoptosis through various mechanisms, and affect tumor differentiation, staging and prognosis. EphA7 may be a potential diagnostic marker and tumor treatment target. This article reviews the effects of EphA7 on a variety of tumor biological processes and pathological characteristics, as well as specific effects and regulatory mechanisms.

CD4+ CD25+ regulatory T-cells role in tumor microenvironment of the squamous cell carcinoma

Introduction: Squamous cell carcinoma (SCC) is the most common skin cancer with a high rate of death. Different lymphocyte populations play an important role in modulating the immune response in the tumor microenvironment. The increase in the proportion of cluster of differentiation (CD)4+ CD25+ regulatory T-cell (Treg) lymphocytes is associated, in different studies, with the increase of the cell multiplication rate. Aim: To analyze the Treg lymphocyte subpopulations and to correlate the results with the presence of the CD8+ cytotoxic T-cell (Tc) lymphocyte population. Materials and Methods: Sixty primary skin SCC specimens were incubated with anti-CD8 (clone SP57) rabbit monoclonal antibody and anti-CD25 (clone 4C9) mouse monoclonal antibody. Results: The ratio of the intratumoral/peritumoral CD4+ CD25+ forkhead box protein p3 (Foxp3) lymphocytes was 0.46, emphasizing that at tumor margins, where tumor aggressiveness is higher, these lymphocytes subpopulations facilitate tumor progression. The comparative analysis of the tumor microenvironment profile revealed that in the case of intratumoral immune response, the number of Tc-type lymphocytes (CD8+) was 3.34 times higher compared to Treg lymphocytes (p<0001). In the peritumoral area, the number of Tc lymphocytes was 5.05 times higher compared to Treg lymphocytes (p<0001). Conclusions: Treg lymphocytes inhibition may cause the suppression of the antitumoral cell immune response in the tumor environment. We believe that Treg lymphocytes should represent a focus of interest for a new personalized therapy. New studies are needed to better understand the immune response in the tumor microenvironment.

Effect of Doxorubicin on Squamous Cell Carcinoma of Skin: Assessment by MRI Relaxometry at 4.7T

Squamous cell carcinoma (SCC) of skin has no standard treatment regimen, resulting in recurrences/metastasis. Although, doxorubicin (Dox), an anthracycline antibiotic has demonstrated some degree of efficacy. Molecular imaging can help in assessment of treatment response and prognosis of SCCs. MRI data showed that spin-spin relaxation (T2) time was longer (138 ± 2 msec) in Dox treated Test-II and there is no significant difference in spin-lattice relaxation (T1) time with respective controls. These findings further corroborated with the histology, proliferation index, apoptotic index, and HMGA1 protein expression. Thus, MRI may be a useful tool for monitoring treatment response noninvasively for skin tumor prognosis.

Aberrant DNA Methylation in Keratoacanthoma

Background

Keratoacanthoma (KA) is a self-limiting epidermal tumor for which histopathological examination sometimes suggests malignancy. Based on inconsistent clinical views, KA can be regarded as both a benign tumor and a variant of squamous cell carcinoma (SCC). Aberrant DNA methylation frequently occurs in malignant tumors but it scarcely occurs in benign tumors. Whether aberrant methylation occurs in KA has not been previously examined.

Objective

The aim is to elucidate whether aberrant methylation of CpG islands (CGI) containing a high density of cytosine-guanine dinucleotide (CpG) sites occurs in KA.

Methods

Five SCC cell lines, two cultured samples of normal human epidermal keratinocytes (NHEKs), 18 clinical SCC samples, and 21 clinical KA samples were analyzed with Infinium HumanMethylation450 BeadChips, quantitative real-time methylation-specific PCR (RT-MSP) and/or bisulfite sequencing.

Results

Genome-wide analyses of NHEK, KA, and SCC indicated that there was a greater number of aberrantly hypermethylated CGIs in SCC than in KA and there were aberrantly hypermethylated CGIs which are common in both. Among the common hypermethylated CGIs, RT-MSP and bisulfite sequencing targeting CGIs located on CCDC17, PVR, and MAP3K11 gene bodies also showed that methylation levels were significantly higher in KA than in normal epidermis. Statistical analyses suggested that the methylation level of CGI located on PVR in SCC might be correlated to lymph node metastasis (P = 0.013, Mann-Whitney U test) and that the methylation level of CGI in MAP3K11 in KA might be correlated to age (P = 0.031, linear regression analysis).

Conclusion

Aberrant DNA methylation occurs in KA.

MiR-20a inhibits cutaneous squamous cell carcinoma metastasis and proliferation by directly targeting LIMK1

BACKGROUND

MicroRNA-20a (miR-20a) plays a key role in tumorigenesis and progression. But its function is reverse in different kinds of malignant tumor, and its role and mechanism in cutaneous squamous cell carcinoma (CSCC) remains unclear.

OBJECT

To determine the miR-20a's roles in CSCC and confirm whether LIMK1 is a direct target gene of miR-20a.

METHODS

First miR-20a and LIMK1 expression levels were detected in six pairs of CSCC tissues and corresponding normal skin by qRT-PCR. Then MTT assays and colony formation assays were performed to evaluate the impact of miR-20a on cell proliferation. In addition, scratch migration assays and transwell invasion assays were performed to check miR-20a's effect on cell metastasis. Since LIMK1 (LIM kinase-1) was predicted as a target gene of miR-20a, the changes of LIMK1 protein and mRNA were measured by western blot and qRT-RCR methods after miR-20a overexpression. Moreover the dual reporter gene assay was performed to confirm whether LIMK1 is a direct target gene of miR-20a. Finally LIMK1 mRNA and miR-20a in other 30 cases of CSCC pathological specimens were determined and a correlation analysis was evaluated.

RESULTS

The miR-20a significantly low-expressed in CSCC tissues compared with that in matched normal tissues while LIMK1 has a relative higher expression. MiR-20a inhibited A431 and SCL-1 proliferation and metastasis. Both of LIMK1 protein and mRNA levels were downregulated after miR-20a overexpression. The dual reporter gene assays revealed that LIMK1 is a direct target gene of miR-20a. Furthermore, qRT-PCR results of LIMK1 mRNA and miR-20a in 30 cases of CSCC pathological specimens showed miR-20a is inversely correlated with LIMK1 expression.

CONCLUSION

Our study demonstrated that miR-20a is involved in the tumor inhibition of CSCC by directly targeting LIMK1 gene. This finding provides potential novel strategies for therapeutic interventions of CSCC.