Impact of tumor microenvironment on adoptive T cell transfer activity

Abstract

Recent advances in immunotherapy have revolutionized the treatment of cancer. The use of adoptive cell therapies (ACT), such as those based on tumor-infiltrating lymphocytes (TILs) or genetically modified cells (transgenic TCR lymphocytes or CAR-T cells), has shown impressive results in the treatment of several types of cancers. However, cancer cells can exploit mechanisms to escape from immunosurveillance, resulting in many patients not responding to these therapies or responding only transiently.

The failure of immunotherapy to achieve long-term tumor control is multifactorial. On the one hand, only a limited percentage of the transferred lymphocytes can circulate through the bloodstream, interacting and crossing the tumor endothelium to infiltrate the tumor.

Metabolic competition, excessive glucose consumption, the high level of lactic acid secretion and the extracellular pH acidification, the shortage of essential amino acids, the hypoxic conditions or the accumulation of fatty acids in the tumor microenvironment (TME) greatly hinder the anti-tumor activity of the immune cells in ACT therapy strategies.

Therefore, a new trend in immunotherapy research seeks to unravel the fundamental biology underpinning the response to therapy and identify new approaches to amplify the efficacy of immunotherapies.

In this review, we address important aspects that may significantly affect the efficacy of ACT, indicating also the therapeutic alternatives currently being implemented to overcome these drawbacks.

Keywords: Acidic pH; Adoptive cell therapy; Extracellular matrix; Immunosuppressor cells; T cell homing; Tumor metabolism; Tumor microenvironment.

CITA DEL ARTÍCULO  Int Rev Cell Mol Biol. 2022;370:1-31. doi: 10.1016/bs.ircmb.2022.03.002. Epub 2022 Jun 21.