Functional Investigation of IGF1R Mutations in Multiple Myeloma.

High expression of the receptor tyrosine kinase (RTK) insulin-like growth factor-1 receptor (IGF1R) and RTK mutations are associated with high-risk/worse prognosis in multiple myeloma (MM). Combining the pIGF1R/pINSR inhibitor linsitinib with the proteasome inhibitor (PI) bortezomib seemed promising in a clinical trial, but IGF1R expression was not associated with therapy response. Because the oncogenic impact of IGF1R mutations is so far unknown, we investigated the functional impact of IGF1R mutations on survival signaling, viability/proliferation and survival response to therapy. We transfected four human myeloma cell lines (HMCLs) with IGF1RWT, IGF1RD1146N and IGF1RN1129S (Sleeping Beauty), generated CRISPR-Cas9 IGF1R knockouts in the HMCLs U-266 (IGF1RWT) and L-363 (IGF1RD1146N) and tested the anti-MM activity of linsitinib alone and in combination with the second-generation PI carfilzomib in seven HMCLs. IGF1R knockout entailed reduced proliferation. Upon IGF1R overexpression, survival signaling was moderately increased in all HCMLs and slightly affected by IGF1RN1129S in one HMCL, whereby the viability remained unaffected. Expression of IGF1RD1146N reduced pIGF1R-Y1135, especially under serum reduction, but did not impact downstream signaling. Linsitinib and carfilzomib showed enhanced anti-myeloma activity in six out of seven HMCL irrespective of the IGF1R mutation status. In conclusion, IGF1R mutations can impact IGF1R activation and/or downstream signaling, and a combination of linsitinib with carfilzomib might be a suitable therapeutic approach for MM patients potentially responsive to IGF1R blockade.

Disturbed expression of the T-cell receptor/CD3 complex and associated signaling molecules in CD30+ T-cell lymphoproliferations.

BACKGROUND: CD30(+) T-cell lymphoproliferations comprise a spectrum of clinically heterogeneous entities, including systemic anaplastic large cell lymphomas (ALK(-) and ALK(+)) and primary cutaneous CD30(+) T-cell lymphoproliferative disorders. While all these entities are characterized by proliferation of highly atypical, anaplastic CD30(+) T cells, the expression of T-cell specific antigens in the tumor cells is not consistently detectable. DESIGN AND METHODS: We evaluated biopsies from 19 patients with primary cutaneous CD30(+) lymphoproliferative disorders, 38 with ALK(-) and 33 with ALK(+) systemic anaplastic large cell lymphoma. The biopsies were examined for the expression of T-cell receptorαß/CD3 complex (CD3γ, δ, ε, ζ), transcription factors regulating T-cell receptor expression (ATF1, ATF2, TCF-1, TCF-1α/LEF-1, Ets1), and molecules of T-cell receptor-associated signaling cascades (Lck, ZAP-70, LAT, bcl-10, Carma1, NFATc1, c-Jun, c-Fos, Syk) using immunohistochemistry. RESULTS: In comparison to the pattern in 20 peripheral T-cell lymphomas, not otherwise specified, we detected a highly disturbed expression of the T-cell receptor/CD3 complex, TCF-1, TCF-1α/LEF-1, Lck, ZAP-70, LAT, NFATc1, c-Jun, c-Fos and Syk in most of the systemic anaplastic large cell lymphomas. In addition, primary cutaneous CD30(+) lymphoproliferative disorders showed such a similar expression pattern to that of systemic anaplastic large cell lymphomas, that none of the markers we investigated can reliably distinguish between these CD30(+) T-cell lymphoproliferations. CONCLUSIONS: Severely altered expression of the T-cell receptor/CD3 complex, T-cell receptor-associated transcription factors and signal transduction molecules is a common characteristic of systemic and cutaneous CD30(+) lymphoproliferations, although the clinical behavior of these entities is very different. Since peripheral T-cell lymphomas, not otherwise specified retain the full expression program required for functioning T-cell receptor signaling, the differential expression of a subset of these markers might be of diagnostic utility in distinguishing peripheral T-cell lymphomas, not otherwise specified from the entire group of CD30(+) lymphoproliferations.

Evaluation of FoxP3 expression in peripheral T-cell lymphoma.

Peripheral T-cell lymphomas (PTCLs) are biologically heterogeneous and have not been successfully correlated with specific T-cell subsets. We investigated PTCL, not otherwise specified (NOS), angioimmunoblastic T-cell lymphoma (AILT), and anaplastic large cell lymphoma (ALCL) cases for FoxP3 expression to determine a potential derivation from regulatory T (Treg) cells. One PTCL-NOS case strongly expressed FoxP3 in the neoplastic T cells and showed unusual histomorphologic features with a dense infiltration of the lymph node by immunoblastic T cells and almost no reactive background infiltrate. The patient died shortly after diagnosis, suggesting that biologic properties of Treg cells may have contributed to the rapidly fatal clinical course. All remaining PTCL-NOS and AILT cases showed FoxP3 positivity only in the reactive infiltrate. Among ALCL cases, 4 of 6 ALK+ cases displayed weak and inhomogeneous FoxP3 expression in the tumor cells. FoxP3+ PTCL-NOS presumably derived from bona fide Treg cells occurs but seems rare in the Western population.