Human antigen R knockdown attenuates the invasive activity of oral cancer cells through inactivation of matrix metalloproteinase-1 gene expression

Background/purpose

The RNA-binding protein human antigen R (HuR) recognizes AU-rich elements in the 3'-untranslated regions of mRNA. The expression of cytoplasmic HuR is related to the malignancy of many carcinomas. The aim of this study is investigation of effect of HuR knockdown for invasive activity of oral carcinoma.

Materials and methods

Proliferation, invasion, real-time PCR, and reporter gene assays were performed to confirm that the knockdown of HuR downregulates the invasive activity of cancer cells. Immunohistochemical staining was performed for high invasive carcinoma, squamous cell carcinoma (SCC) and low invasive carcinoma, verrucous carcinoma (VC), to determine if the localization of cytoplasmic HuR is related to matrix metalloproteinase-1 (MMP-1) expression.

Results

Invasive activity was significantly lower in HuR knockdown cancer cells than in control cells. A luciferase assay revealed that HuR knockdown inactivated the promoter activity of the MMP-1 gene. The mRNA levels of the transcription factors required for MMP-1 expression, including c-fos and c-jun, were decreased in HuR knockdown cancer cells. Immunohistochemical analysis revealed the level of cytoplasmic HuR and MMP-1 in invasive carcinoma to be higher than in low invasive cancer. HuR induced MMP-1 expression in the invasive front of most SCC cases.

Conclusion

HuR knockdown attenuated the invasive activity of cancer cells by decreasing the expression of the MMP-1, at least partially. HuR localization may help determine the invasive phenotype of cancer cells and inhibit cancer cell invasion. Furthermore, in oral SCC, HuR may be related to invasive activity through the expression of MMP-1.

Hydroelectric actuator for 3-dimensional analysis of electrophoretic and dielectrophoretic behavior of cancer cells; suitable in diagnosis and invasion studies

Cancer is a cellular-based disease, so cytological diagnosis is one of the main challenges for its early detection. An extensive number of diagnostic methods have been developed to separate cancerous cells from normal ones, in electrical methods attract progressive attention. Identifying and specifying different cells requires understanding their dielectric and electric properties. This study evaluated MDA-MB-231, HUVEC, and MCF-10A cell lines, WBCs isolated from blood, and patient-derived cell samples with a cylindrical body with two transparent FTO (fluorine-doped tin oxide) plate electrodes. Cell mobility rates were recorded in response to these stimuli. It was observed that cancer cells demonstrate drastic changes in their motility in the presence and absence of an electric field (DC/AC). Also, solution viscosity's effect on cancer cells' capturing efficacy was evaluated. This research's main distinguished specification uses a non-microfluidic platform to detect and pathologically evaluate cytological samples with a simple, cheap, and repeatable platform. The capturing procedure was carried out on a cytological slide without any complicated electrode patterning with the ability of cytological staining. Moreover, this platform successfully designed and experimented with the invasion assay (the ability of captured cancer cells to invade normal cells).

Analysis of Invasive Activity of CAF Spheroids into Three Dimensional (3D) Collagen Matrices

Tumor growth and progression is the result of a complex process controlled not only by malignant cancer cells but also by the surrounding tumor microenvironment (TME). Cancer associated fibroblasts (CAFs), the most abundant cellular component of TME, play an active role in tumor invasion and metastasis by promoting cancer cell invasion through cell-cell interactions and secretion of pro-invasive factors such as extracellular matrix (ECM)-degrading proteases. Due to their tumor-promoting activities, there is an emerging interest in investigating CAFs biology and its potential as drug targets for cancer therapies. Here we describe an easy and highly reproducible quantitative method to analyze CAF invasive activity by forming multicellular spheroids embedded into a three-dimensional (3D) matrix that mimics in vivo ECM. Subsequently, invasion is monitored over time using a time-lapse microscope. We also provide an automated image analysis system that enables the rapid quantification of the spheroid area increase (invasive area) over time. The use of a 96-well plate format with one CAF spheroid per well and the automated analysis provides a method suitable for drug screening test, such as protease inhibitors.

High expression of EPB41L5, an integral component of the Arf6-driven mesenchymal program, correlates with poor prognosis of squamous cell carcinoma of the tongue

Background

Squamous cell carcinoma of the tongue (tongue SCC) is a major subtype of head and neck squamous cell carcinoma (HNSCC), which is an intractable cancer under current therapeutics. ARF6 and its effector AMAP1 are often overexpressed in different types of cancers, such as breast cancer and renal cancer, and in these cancers, AMAP1 binds to EPB41L5 to promote invasion, metastasis, and drug resistance. EPB41L5 is a mesenchymal-specific protein, normally induced during epithelial-mesenchymal transition (EMT) to promote focal adhesion dynamics. Similarly to breast cancer and renal cancer, the acquisition of mesenchymal phenotypes is the key process that drives the malignancy of HNSCC. We previously showed that the overexpression of AMAP1 in tongue SCC is statistically correlated with the poor outcome of patients. In this study, we examined whether tongue SCC also expresses EPB41L5 at high levels.

Results

Immunohistochemical staining of clinical specimens of tongue SCC demonstrated that high expression levels of EPB41L5 statistically correlate with poor disease-free survival and poor overall survival rates of patients. The tongue SCC cell line SCC-9, which overexpress Arf6 and AMAP1, also expressed EPB41L5 at high levels to promote invasiveness, whereas the weakly invasive SCC-25 cells did not express EPB41L5 at notable levels. Among the different EMT-associated transcriptional factors, ZEB1 was previously found to be most crucial in inducing EPB41L5 in breast cancer and renal cancer. In contrast, expression levels of ZEB1 did not correlate with the expression levels of EPB41L5 in tongue SCC, whereas KLF8 and FOXO3 levels showed positive correlations with EPB41L5 levels. Moreover, silencing of EPB41L5 only marginally improved the drug resistance of SCC-9 cells, even when coupled with ionizing radiation.

Conclusion

Our results indicate that activation of the cancer mesenchymal program in tongue SCC, which leads to EPB41L5 expression, closely correlates with the poor prognosis of patients. However, ZEB1 was not the major inducer of EPB41L5 in tongue SCC, unlike in breast cancer and renal cancer. Thus, processes that trigger the mesenchymal program of tongue SCC, which drives their malignancies, seem to be substantially different from those of other cancers.