<i>Lab-on-a-chip and integrated strategies in tumor immunotheraphy</i>

Abstract

Background While conventional chemotherapy and radiation therapy have improved the survival of many cancer patients, there are still major disadvantages associated with these treatments such as high toxicity and drug-resistance. The possibility to manipulate the immune system to recognize and kill tumor cells is very attractive despite numerous obstacles remaining to be overcome. In particular, the ability of the immune system to destroy disseminated metastases in a specific way makes immunotherapy an attractive alternative to conventional therapies. Nevertheless, other unconventional technologies emerged in recent years seem to be very promising; in particular the analysis and monitoring of single cell-to-cell interactions and the capability to individually control single cells by Lab-on-a-chip devices have become of great interest in different areas of life sciences. These new technologies, in combination with progresses reached in anti-tumor vaccines, could be useful to improve immune T cell responses against tumor antigen for a more efficient immunotherapy. Aims This thesis focuses on two tumor immunotherapy issues: 1) design, realization and validation of innovative Lab-on-a-chip devices for immune system study, that allows single tumor cell and effector cell interaction, detection and isolation; 2) identification of molecular mechanisms that prevent EBV-associated tumors (e.g. Burkitt’s lymphoma) recognition by T cells and study of their potential correction by specific treatments. The main goal of this study remains indeed the evaluation of an integrated strategy for immunotherapy development enhancing for malignancies treatment. Methods Biocompatibility test, generation of memory CTL cultures, 51Cr release assay, IFN-Elispot, proteasomes purification, western blot assay, enzymatic assay, immunofluorescence, RT-PCR. Main Results As concerns the first part of the thesis, a main achievement was the design of Lab-on-a-chip platform that combined microfluidics and electronics together, consisting in a matrix of up to thousand microwells where living cells can be deposited. Subsequently, different materials have been evaluated to identify the most biocompatible ones for biosensor manufacturing. Once developed Lab-on-a-chip prototype, it has been tested from a functional point of view. In particular, it has been demonstrated that the biosensor is able to isolate and trap single cells inside microwells by dielectrophoresis, that recovered cells are still alive and that their biological functions and gene expression remain unaltered. Furthermore, tumor cell lysis by immune effector cells could be successfully monitored inside device microwells, showing that biosensor could be used for cell to cell interaction studies. Regarding the second aim of this thesis, it has been identified a new epitope-specific T cell response against EBV nuclear antigen 1 (EBNA1). It has also been demonstrated that CTLs specific for another EBNA1-derived epitope (referred as HPV) are detectable in the majority of HLA-B35 individuals, and recognize EBV-transformed B lymphocytes (LCL) but not Burkitt’s lymphoma (BL). Afterwards LCL and BL have been compared for their antigen processing machinery, demonstrating that one of the major differences was at the proteasome level; indeed, proteasomes from BL cells have displayed a far lower chymotryptic and tryptic-like activities. Interestingly, it has also been shown that treatment with proteasome inhibitors partially restored the capacity of BL cells to present the HPV epitope. Conclusions The results achieved in single cell manipulation and cell to cell analysis interaction by Lab-on-a-chip technology, and the findings reached to improve BL immune recognition, represent an implementation of innovative tools that could allow important progresses in cancer diagnosis and immunotherapy.