miR-135b mediates NPM-ALK-driven oncogenicity and renders IL-17-producing immunophenotype to anaplastic large cell lymphoma.

Many transformed lymphoma cells show immune-phenotypes resembling the corresponding normal lymphocytes; thus, they provide a guide for proper diagnosis and present promising routes to improve their pathophysiologic understanding and to identify novel therapeutic targets. However, the underlying molecular mechanism(s) of these aberrant immune-phenotypes is largely unknown. Here, we report that microRNA-135b (miR-135b) mediates nucleophosmin-anaplastic lymphoma kinase (NPM-ALK)-driven oncogenicity and empowers IL-17-producing immunophenotype in anaplastic large cell lymphoma (ALCL). NPM-ALK oncogene strongly promoted the expression of miR-135b and its host gene LEMD1 through activation of signal transducer and activator of transcription (STAT) 3. In turn, elevated miR-135b targeted FOXO1 in ALCL cells. miR-135b introduction also decreased chemosensitivity in Jurkat cells, suggesting its contribution to oncogenic activities of NPM-ALK. Interestingly, miR-135b suppressed T-helper (Th) 2 master regulators STAT6 and GATA3, and miR-135b blockade attenuated IL-17 production and paracrine inflammatory response by ALCL cells, indicating that miR-135b-mediated Th2 suppression may lead to the skewing to ALCL immunophenotype overlapping with Th17 cells. Furthermore, antisense-based miR-135b inhibition reduced tumor angiogenesis and growth in vivo, demonstrating significance of this "Th17 mimic" pathway as a therapeutic target. These results collectively illuminated unique contribution of oncogenic kinase-linked microRNA to tumorigenesis through modulation of tumor immune-phenotype and microenvironment.