CRISPR-based screens uncover determinants of immunotherapy response in multiple myeloma

Poornima Ramkumar1, Anthony B Abarientos1, Ruilin Tian1

  • 1Institute for Neurodegenerative Diseases and.

Blood Advances
|June 27, 2020
PubMed

Insights

Researchers identified ways to increase B-cell maturation antigen (BCMA) on cancer cells, potentially restoring immunotherapy effectiveness. Inhibiting HDAC7 and Sec61 boosted BCMA levels and improved treatment outcomes in multiple myeloma models.

Area of Science:

  • Cancer immunotherapy
  • Functional genomics
  • Multiple myeloma therapeutics

Background:

  • Immunotherapy resistance in cancer frequently arises from decreased antigen expression on tumor cells.
  • Restoring target antigen levels on cancer cells can re-sensitize them to immunotherapy.
  • B-cell maturation antigen (BCMA) is a key immunotherapy target in multiple myeloma.

Purpose of the Study:

  • To systematically identify genetic pathways regulating cell surface BCMA expression using CRISPR screening.
  • To discover novel therapeutic targets for enhancing BCMA expression and immunotherapy efficacy.
  • To investigate mechanisms of response and resistance to BCMA-targeted chimeric antigen receptor T cell (CAR-T cell) therapy.

Main Methods:

  • CRISPR interference (CRISPRi) and CRISPR activation (CRISPRa) functional genomics screens.
  • Pharmacologic inhibition of identified pathways (HDAC7, Sec61 complex).
  • BCMA-targeted antibody-drug conjugate efficacy assessment.
  • CRISPRi-based CAR-T cell coculture screens in multiple myeloma models.

Main Results:

  • Pharmacologic inhibition of HDAC7 and the Sec61 complex significantly increased cell surface BCMA expression.
  • Increased BCMA levels were observed in primary patient-derived multiple myeloma cells.
  • Sec61 complex inhibition enhanced the anti-myeloma activity of a BCMA-targeted antibody-drug conjugate.
  • CRISPR screens identified both antigen-dependent and -independent factors influencing CAR-T cell therapy response.

Conclusions:

  • Targeting HDAC7 and the Sec61 complex represents a promising strategy to enhance BCMA expression for immunotherapy.
  • CRISPR-based functional screens are powerful tools for uncovering mechanisms of immunotherapy response and resistance.
  • This study provides a foundation for developing combination therapies to overcome immunotherapy resistance in multiple myeloma.