Cell Death in the Tumor Microenvironment: Implications for Cancer Immunotherapy

Cells. 2020 Sep 29;9(10):2207. doi: 10.3390/cells9102207.

Abstract

The physiological fate of cells that die by apoptosis is their prompt and efficient removal by efferocytosis. During these processes, apoptotic cells release intracellular constituents that include purine nucleotides, lysophosphatidylcholine (LPC), and Sphingosine-1-phosphate (S1P) that induce migration and chemo-attraction of phagocytes as well as mitogens and extracellular membrane-bound vesicles that contribute to apoptosis-induced compensatory proliferation and alteration of the extracellular matrix and the vascular network. Additionally, during efferocytosis, phagocytic cells produce a number of anti-inflammatory and resolving factors, and, together with apoptotic cells, efferocytic events have a homeostatic function that regulates tissue repair. These homeostatic functions are dysregulated in cancers, where, aforementioned events, if not properly controlled, can lead to cancer progression and immune escape. Here, we summarize evidence that apoptosis and efferocytosis are exploited in cancer, as well as discuss current translation and clinical efforts to harness signals from dying cells into therapeutic strategies.

Keywords: apoptosis; cancer; compensatory proliferation; efferocytosis; immune evasion; phosphatidylserine (PS).

Publication types

  • Review

MeSH terms

  • Apoptosis / drug effects
  • Apoptosis / immunology*
  • Apoptosis / physiology
  • Caspases / metabolism
  • Cell Death / drug effects
  • Cell Death / immunology*
  • Humans
  • Lysophosphatidylcholines / metabolism
  • Lysophospholipids / metabolism
  • Molecular Targeted Therapy / methods*
  • Neoplasms / drug therapy
  • Neoplasms / immunology*
  • Neoplasms / pathology
  • Phagocytosis / genetics
  • Phagocytosis / immunology*
  • Phosphatidylserines / metabolism*
  • Purine Nucleotides / metabolism
  • Sphingosine / analogs & derivatives
  • Sphingosine / metabolism
  • Tumor Escape*
  • Tumor Microenvironment / immunology*

Substances

  • Lysophosphatidylcholines
  • Lysophospholipids
  • Phosphatidylserines
  • Purine Nucleotides
  • sphingosine 1-phosphate
  • Caspases
  • Sphingosine