In vitro Assays for the Detection of Calreticulin Exposure, ATP and HMGB1 Release upon Cell Death

Abstract

Accumulating evidence is revealing the essential role of immune system in cancer treatment. Certain chemotherapeutic drugs can potently induce the release of ‘cell death associated molecular patterns’ (CDAMPs), which accompanies cancer cell demise. CDAMPs can engage corresponding receptors on immune cells and stimulate immune responses to achieve long-term tumor control (Ma et al., 2013; Ma et al., 2014; Yang et al., 2015). Among reported CDAMPs, calreticulin (CALR), ATP and HMGB1 are well known for their immune-stimulatory effect. Here we describe the assays that we applied to measure cell death and these CDAMPs. Briefly, cell death can be analyzed by co-staining of 4’,6-diamidino-2-phenylindole (DAPI) with 3,3’-Dihexyloxacarbocyanine Iodide [DiOC6(3)] or Annexin V. CALR exposure on the cell membrane can be detected by flow cytometry. ATP and HMGB1 release can be quantified by luminescence assay and ELISA assay respectively.