Dr Maccalli talks to ecancertv at the 1st Immunotherapy of Cancer Conference ( ITOC ) in Munich about immuno-biological properties of human cancer stem cells.

Understanding these cells could lead to understanding chemotherapy resistance, and it appears that the cells have the potential to play an immunoregulatory role in T-cell response

Cells with 'stem cell properties', denominated cancer stem cells (CSCs), have been recently isolated from a variety of human solid tumours. These cells have been considered as responsible of resistance to standard therapy such as chemotherapy and radiotherapy.

Immunotherapy, due to its specificity and lack of toxicity can represent a promising approach to target cancer stem cells. Thus, it is relevant to assess whether CSCs isolated from solid tumours, can be exploited as source of antigens to elicit T cell-mediated immune responses and to design novel immunotherapeutic protocols for tumours.

CSCs from glioblastoma multiforme (GBM) and colorectal cancer (CRC) have been isolated from tumour biopsies and have been biologically characterized. Moreover, a detailed immunological characterization of these CSCs has been performed leading to the identification of a low immunogenic profile with negative immunoregulatory properties.

Dr Maccalli's team found that both CSCs and the differentiated counterpart of tumours (FBS tumour cells) expressed immune modulatory molecules, such as CTLA-4, PD- 1, PDL-1 and B7H3, with, in some cases, higher levels in CSCS vs. FBS tumour cells. 

Multiple mechanisms of immunoregulation that are exploited by CSCs to escape from T cell-mediated surveillance have been identified. These results may allow designing more effective immunotherapy protocols to target CSCs from GBM and/or CRC patients.