Elhousiny, Moustafa (2019) The effect of substance P (SP) on adhesion of Jurkat leukemia cells and squamous carcinoma cells (SCC) to vascular endothelial cells and role in metastasis. PhD thesis, James Cook University.

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Abstract

Metastasis is the leading cause of fatality in 90% of cancers, and approximately 60% of all cancer cases will have either regional or distant metastasis at initial diagnosis. Global data shows that survival rates drop significantly with the advance of disease stage and metastatic activity; therefore, patients with localised disease have a far better prognosis than those with disseminated tumours. In this aspect, Leukaemia and oral squamous-cell carcinoma (OSCC) are invasive neoplasms. Both cancers are considered the worst prognosis cancers with an overall survival rate of 50% or slightly higher.

The accumulating research suggests that inflammation is more likely to act in favour of tumour initiation and metastasis. The striking similarity which exists between the out flux of tumour mass in the circulation and that of inflammatory exudates in wound healing points to the possibility that the same mediators might be utilised for both purposes. Substance P (SP) is a primary regulator of neurogenic inflammation mainly acting as a trigger for vasodilatation, plasma protein extravasation and leukocyte adhesion to vascular endothelial cells. SP has been proposed as a model that can explain the inflammation-tumour relationship. Therefore, the link between the role of SP and the extravasation of tumour cells into the circulation represents an attractive opportunity for unravelling the metastatic mechanisms.

We carried a systematic review which identified nine inflammatory mediators associated with metastasis. The 16 articles reported lymph node metastasis and one article reported both lymph node and distant metastasis. The inflammatory mediators identified were CXCR4 (six studies), CXCL12 (SDF-1), CCR7, IL-6 (two studies each), IL-18, CCL20 (MIP-3), CXCL1 (GRO-1), CCL3, CXCR2 (one study each). This review systematically summarises the evidence of the prognostic role of inflammatory mediators in predicting metastasis/metastatic stages in OSCC. Additionally, it compares the available evidence from clinical and experimental animal settings.

Our experimental results showed that SP increased the adhesion of Jurkat Leukaemia cell lines in a time-course treatment with a peak adhesion increase at three-four hours. SP increased the adhesion of H157, CAL27, and DOK cells to HUVEC endothelial cells (P < 0.001), significantly, in a time-dependent treatment with peak adhesion at three hours. It has been demonstrated that SP is expressed by several tumours and several roles have been proposed for its action in tumour growth and progression. Our study describes a new role for SP in stimulating an early onset adhesion of tumour-endothelial adhesion.

We found that treating endothelial cells with either stimulating factor or inhibitor produces more potent levels of adhesion which may 1) explain the organ-specific metastasis of cancers; and 2) highlight the active interaction of tumour-endothelial cells during adhesion. Moreover, our data suggests that inhibition of adhesion levels – achieved using cycloheximide, which blocks translation of messenger RNA on the cytosolic 80S ribosomes but does not inhibit the organelle protein synthesis – did not achieve higher levels such as the one inflicted with monoclonal antibodies. This might suggest that tumour cells highly express adhesion molecules as well as inflammatory receptors.

Our data also suggests that in Jurkat cells, CAL27 and BICR22, SP 1mcg/ml treatment has increased both CD 11 (not significant) and CD 49 (P < 0.05), but not CD15s expression in 1-48 hour time-scale treatment, as indicated by the FACS analysis. Anti-human monoclonal antibodies to VCAM or ICAM significantly inhibited adhesion levels to below the untreated baseline levels. The NK-1R antagonist was only effective in inhibiting adhesion molecule expression in Jurkat and CAL27. No other effect was noted in the other OSCC cell lines.

We hypothesised that adhesion molecules were the main requirement of the adhesion process, and adhesion molecule expression followed the pattern predicted which increased from no expression in the normal oral keratinocytes to the lymph node positive cell line H157 and declined in the metastatic cells BICR22, for the three adhesion molecules. The pre-cancer cell line DOK had an elevated expression profile which agrees with previous studies, suggesting an early invasive/metastatic phenotype in the tumour cycle.

Our results did not prove any significant effect for SP on the release of MMP-2 in either Jurkat cells or OSCC cell lines. This was against the predicted pattern in which we hypothesised that SP would trigger up-regulation of MMP enzymes to facilitate the transmigration of tumour cells through the endothelium.

The resulting model represents a novel approach in cancer treatment where the main target is prevention of metastasis. This paradigm shift has a powerful potential to develop effective anti-metastatic therapies through interfering with the metastatic cycle. The data resulting from the systematic review as well as the experimental findings can be integrated for future implementation in two main categories.

In conclusion, the study identifies a new role for Substance P in mediating an early onset adhesion of cancer cells to endothelial cells. The study also highlights the role of the NK-1R antagonist as a novel therapy in inhibiting this adhesion in those cell lines. A combined therapy of the NK-1R antagonist and monoclonal anti-adhesion molecule would be powerful in preventing the onset of metastasis. These primary data warrant further research through animal models to confirm this role for Substance P.

Item ID:	60366
Item Type:	Thesis (PhD)
Copyright Information:	Copyright © 2019 Moustafa Elhousiny.
Date Deposited:	13 Sep 2019 04:52
FoR Codes:	11 MEDICAL AND HEALTH SCIENCES > 1112 Oncology and Carcinogenesis > 111201 Cancer Cell Biology @ 50% 11 MEDICAL AND HEALTH SCIENCES > 1112 Oncology and Carcinogenesis > 111299 Oncology and Carcinogenesis not elsewhere classified @ 50%
SEO Codes:	92 HEALTH > 9201 Clinical Health (Organs, Diseases and Abnormal Conditions) > 920102 Cancer and Related Disorders @ 50% 97 EXPANDING KNOWLEDGE > 970111 Expanding Knowledge in the Medical and Health Sciences @ 50%
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