Generation of metastatic melanoma specific antibodies by affinity purification

Late stage melanoma is hallmarked by low NLGN4X expression leading to HIF1A accumulation

BACKGROUND

Despite ongoing research and recent advances in therapy, metastatic melanoma remains one of the cancers with the worst prognosis. Here we studied the postsynaptic cell adhesion molecule Neuroligin 4X (NLGN4X) and investigated its role in melanoma progression.

METHODS

We analysed histologic samples to assess the expression and predictive value of NLGN4X in human melanoma. The oncogenic role of NLGN4X was determined by loss or gain-of-function experiments in vitro as well as by analysis of tumorspheres, which were grafted to human skin organoids derived from pluripotent stem cells. Whole genome expression analysis and validation experiments were performed to clarify the molecular mechanism.

RESULTS

We identified that suppression of NLGN4X down regulated the prefoldin member Von Hippel-Lindau binding protein 1 (VBP1). Moreover, loss of VBP1 was sufficient for accumulation of HIF1A and HIF1A signalling was further shown to be essential for the acquisition of migratory properties in melanoma. We re-established NLGN4X expression in late stage melanoma lines and observed decreased tumour growth after transplantation to human skin organoids generated from pluripotent stem cells. In line, we showed that high amounts of NLGN4X and its target VBP1 in human patient samples had a beneficial prognostic effect on patient survival.

CONCLUSION

In view of these findings, we propose that decreased amounts of NLGN4X are indicative of a metastatic melanoma phenotype and that loss of NLGN4X provides a novel mechanism for HIF induction.

Antibody-Based Targeted Interventions for the Diagnosis and Treatment of Skin Cancers

BACKGROUND

Cutaneous malignancies most commonly arise from skin epidermal cells. These cancers may rapidly progress from benign to a metastatic phase. Surgical resection represents the gold standard therapeutic treatment of non-metastatic skin cancer while chemo- and/or radiotherapy are often used against metastatic tumors. However, these therapeutic treatments are limited by the development of resistance and toxic side effects, resulting from the passive accumulation of cytotoxic drugs within healthy cells.

OBJECTIVE

This review aims to elucidate how the use of monoclonal Antibodies (mAbs) targeting specific Tumor Associated Antigens (TAAs) is paving the way to improved treatment. These mAbs are used as therapeutic or diagnostic carriers that can specifically deliver cytotoxic molecules, fluorophores or radiolabels to cancer cells that overexpress specific target antigens.

RESULTS

mAbs raised against TAAs are widely in use for e.g. differential diagnosis, prognosis and therapy of skin cancers. Antibody-Drug Conjugates (ADCs) particularly show remarkable potential. The safest ADCs reported to date use non-toxic photo-activatable Photosensitizers (PSs), allowing targeted Photodynamic Therapy (PDT) resulting in targeted delivery of PS into cancer cells and selective killing after light activation without harming the normal cell population. The use of near-infrared-emitting PSs enables both diagnostic and therapeutic applications upon light activation at the specific wavelengths.

CONCLUSION

Antibody-based approaches are presenting an array of opportunities to complement and improve current methods employed for skin cancer diagnosis and treatment.