Bozena Werynska

Prognostic significance of SOX18 expression in non-small cell lung cancer

Recent studies have demonstrated the involvement of SOX18 transcription factor in blood and lymphatic vessel development, as well as in wound healing processes. SOX18 expression has been noted in cancer cells of various tumours, including lung cancer. However, the exact role of SOX18 expression in non-small cell lung cancer (NSCLC) remains to be determined. The present study, therefore, assessed its expression in 198 cases of NSCLC, consisting of 94 adenocarcinomas (AC), 89 squamous cell carcinomas (SQC) and 15 large cell carcinomas (LCC). The analysis utilized immunohistochemistry (IHC) and, in 42 cases, molecular methods. SOX18 expression was also determined in NSCLC cell lines (NCI-H1703, NCI-H522 and A549) and in normal lung fibroblasts (IMR-90). SOX18 was found to be expressed in nuclei, as well as in the cytoplasm of cancer cells, in the majority of studied cases. SOX18 mRNA expression was significantly lower in NSCLC than in non-malignant lung tissue (p<0.0001). However, SOX18 protein expression levels were higher in NSCLC tissues (p<0.005) and in the examined lung cancer cell lines. No SOX18 expression was noted in the IMR-90 cell line. In paraffin sections, a positive correlation between the Ki-67 antigen and nuclear SOX18 expression (r=0.17, p<0.05) was noted. In univariate survival analysis, cytoplasmic SOX18 expression correlated with poor patient outcome in the whole study and in AC cohorts (both p<0.05). Based on these results, SOX18 may be involved in the progression of NSCLC.

Role of lymphangiogenesis in lung cancer.

Lung cancer represents one of the most frequent causes of death due to neoplastic disease in Poland and around the world. The high mortality which accompany neoplastic diseases used to be ascribed mainly to dissemination of cancerous cells. Studies on animal models suggest that tumour lymphangiogenesis represents the principal factor in the process of metastases formation. Lymphangiogenesis involves a process of formation of new lymphatic vessels from already existing lymphatic capillaries. Lymphangiogenesis is stimulated by vascular endothelial growth factors (VEGF) and other, recently reported factors, such as, e.g., cyclooxygenase 2, fibroblast growth factor 2, angiopoetin-1 and the insulin-resembling growth factor. In lymphangiogenesis a key role is played by neutropilin 2 or podoplanin and this promoted development of studies on lymphangiogenesis. Activation of VEGF-C/VEGF-D/VEGFR-3 axis increases motility and invasiveness of neoplastic cells, promotes development of metastases in several types of tumours such as, e.g., lung cancer, mammary carcinoma, cancers of the neck, prostate and large intestine. In recent years lymphangiogenesis provided topic of many studies. A positive correlation was detected between expressions of VEGF-C/D and VEGFR-3 in non-small cell lung cancer. In patients with lung cancer with high expression of VEGF-C a markedly abbreviated survival was noted. Positive correlation was detected between expression of VEGF-C and VEGF-D on one hand and expression of LYVE-1 on the other in sentinel lymph nodes with metastases of neoplastic cells in patients with non-small cell lung cancer. Also, high density of lymphatic vessels and high density of intraneoplastic microvessels proved to be independent poor prognostic indices in patients with non-small cell lung cancer. Extensive hope is linked to studies on inhibitors of lymphangiogenesis, which may improve results of treatment also in tumour patients.

Influence of miR-7a and miR-24-3p on the SOX18 transcript in lung adenocarcinoma

The molecular pathogenesis of the development of non-small cell lung carcinomas (NSCLCs) is extremely complex. Understanding the molecular basis of the development of this malignant tumor may enable the use of targeted therapy, which may result in a better treatment outome for these patients. Adenocarcinoma (AC) is the most common NSCLC subtype, equally common among smokers and non-smokers, and its pathogenesis remains unknown. The SOX18 protein is an important protein that plays a role in the development of blood and lymphatic vessels during the process of embryogenesis. Recent studies have also shown that the SOX18 protein may play a significant role in tumors, including lung cancers. In the present study, we analyzed the expression of the SOX18 protein and the mRNA level in postoperative samples of AC and non-malignant lung tissues (NMLTs), and a disparity in both levels was observed. Based on our previous observations that miR-7a and miR-24-3p are able to modulate SOX18 expression in NSCLC, the main aim of this study was to verify the miRNA modulation of the SOX18 transcript with the use of the MirTrap System in established lung cancer cell lines NCI-H1703, NCI-H522 and A549. The SOX18 mRNA expression level was significantly lower in AC than that noted in the NMLTs (P<0.0001). However, the protein levels were higher in AC cases compared to levels noted in the NMLTs (P<0.0001). Additionally, correlations between the RQ values of SOX18 in NMLT and AC cases (r=0.8195, P=0.0001), and between miR-7a and miR24-3p in AC cases (r=0.4344, P=0.0016), were noted. In conclusion, we confirmed that miR-7a and miR-24-3p are more highly expressed in NMLTs than in the AC samples, and that they modulate the SOX18 transcript in NSCLC cells.