Cell by cell immuno- and cancer marker profiling for non-small cell lung cancer (NSCLC) tissue sample using non-enzymatic tissue dissociation and high-parameter flow cytometry
Non-small cell lung cancer (NSCLC) is the most common type of lung cancer, accounting for 80-85% cases of lung cancer. It has poor prognosis as most NSCLC patients are at advanced stage when diagnosed. The development of immunotherapy blocking the PD-1/PD-L1 ligand pathway, in recent years, has shed light on new treatment for lung cancer. An in-depth understanding of the interaction between immune system and tumor will help to identify novel markers for lung cancer treatment.
In this study, we performed a comprehensive study on 10 NSCLC patient tissue samples with paired blood samples for circulating tumor cells (CTCs). The solid tissue biopsy samples were dissociated into single cells by non-enzymatic tissue homogenization (IncellDx IncellPREPTM). The single cell suspensions were stained simultaneously with multiple (>20) immune check point markers (including PD-1*, PD-L1*, TIM-3*, LAG-3*, and CTLA-4*), cancer markers (such as EGFR* and ALK* fusion protein), and a cell cycle dye. The samples were interrogated on a novel, innovative, high parameter, spectral flow cytometer Cytek AuroraTM. Markers on subsets of immune cell and cancer cell populations were investigated.
Our results showed the association of high levels of immune check point marker and cancer marker expressions with the high level of aneuploidy (indicated by DNA index >1.05), and the aggressiveness of the cancer (indicated by the number of CTCs). High numbers of CTCs were associated with aneuploidy, increased Post G0-G1%, and high expression of LAG-3, TIM-3, and PD-1.
Multi-parametric flow cytometry allows simultaneous profiling of multiple immune and cancer markers on cancer samples at the single cell level. The knowledge acquired from these studies will enhance our understanding of cancer immune system, cancer cells, and the interaction between immune system and the cancer. It will potentially transform patient diagnosis, disease monitoring, and drug discovery. Our study demonstrated a powerful method to study solid tumors that may provide important information for successful precision cancer immunotherapy.
*PD-1: programmed death-1; *PD-L1: programmed death-ligand 1; *TIM-3: mucin domain-3-containing molecule-3; *LAG-3: lymphocyte-activation gene-3; *CTLA-4: cytotoxic T-lymphocyte antigen-4; *EGFR: epidermal growth factor receptor; *ALK: anaplastic lymphoma kinase.