Tyrosine phosphatases regulate resistance to ALK inhibitors in ALK+ anaplastic large cell lymphoma

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Anaplastic large cell lymphomas (ALCLs) often harbor anaplastic lymphoma kinase (ALK) gene fusions.
• Tyrosine kinase inhibitors (TKIs) are used for relapsed ALK-positive (ALK+) ALCL, but resistance can emerge.
• Understanding resistance mechanisms is crucial for improving ALK TKI therapy.

Purpose of the Study:

• To identify novel mechanisms of resistance to ALK TKIs in ALK+ ALCL.
• To elucidate the role of phosphatases in regulating ALK signaling and TKI sensitivity.
• To explore combination strategies for overcoming TKI resistance.

Main Methods:

• Genomic loss-of-function screens to identify resistance genes.
• In vitro and in vivo experiments to assess TKI resistance.
• Phosphorylation assays, RNA sequencing, and signaling pathway analysis.
• Combination therapy studies using ALK inhibitors and SHP2 inhibitors.

Main Results:

• PTPN1 and PTPN2 phosphatases were identified as key drivers of ALK TKI resistance.
• Loss of PTPN1 or PTPN2 conferred resistance by hyperactivating SHP2, MAPK, and JAK/STAT pathways.
• ALK and STAT3 signaling repressed PTPN1 transcription.
• Patient samples with TKI resistance showed decreased PTPN1/PTPN2 and increased SHP2 expression.
• Combined inhibition of ALK and SHP2 synergistically reduced ALCL growth and overcame resistance.

Conclusions:

• PTPN1 and PTPN2 are critical ALK phosphatases that regulate sensitivity to ALK TKIs in ALCL.
• Combined blockade of ALK and SHP2 is a promising strategy to enhance TKI efficacy in both sensitive and resistant ALK+ ALCL.
• Targeting SHP2 offers a potential therapeutic approach to overcome acquired resistance to ALK inhibitors.