Tag: lymphoma cancer

Transcription Regulation Targeting Presents Potential New Paradigm in Treating Patients with Peripheral T-cell Lymphoma

lecBy Leandro Cerchietti, MD

Peripheral T-cell lymphomas (PTCL) are a clinically aggressive disease with poor responses to current modes of therapy and a dismal survival rate. In an abstract presented before the 56th annual American Society of Hematology conference we sought to identify an active new drug for PTCL patients.

We began by performing a cell-based progressive screen from a library of 105 anti-neoplastic drugs in clinical use. Initially within the clinical-range limit we identified 3 active drugs groups HDAC inhibitors (HDI, romidepsin), proteasome inhibitors (bortezomib, carfilozimib), and transcription inhibitors (dactinomycin). Secondary screenings were conducted for the active drug groups with six drug concentrations, in an extended panel of 9 TCL cell lines. To expand the scope of our drug groups we added vorinostat, panobinostat and valproic acid for HDI and SNS032 (CDK9>2>>7 inhibitor) and THZ1 (CDK7>12 inhibitor) for transcription inhibitors.

We found that the most active drugs were bortezomib, carfilzomib, romidepsin, dactinomycin, and THZ1, focusing on the transcriptional inhibitors, using THZ1 to investigate the functional relevance of CDK7/12 targeting in PTCL. THZ1 was found to decrease mRNA and protein levels of MCL1, JAK1, and MYC as early as 3 hours into treatment. The levels of anti-apoptotic proteins BCL2, BCL-XL, JUND, and NFkB also decreased, while proteins like the pro-apoptotic BAX increased.

In conclusion we found a mechanism by which CDK7/12 inhibition with the compound THZ1 simultaneously inhibits prominent PTCL survival pathways, causing apoptosis and re-sensitization to BCL2-family inhibitors. These findings led us to identify a mechanism by which CDK7/12 inhibition and presents a potential new paradigm in treating patients with PTCL.

Possible New Target for Novel Targeting Therapies in the Treatment of Patients with ALK-ALCL

ggi9001By Giorgio Inghirami, MD

Although the role of ALK chimeras is well known in the pathogenesis of ALK + Anaplastic Large Cell Lymphoma (ALCL), the mechanisms underlying the transformation of ALK-ALCL is unknown. In an abstract presented before the 56th Annual Meeting of the American Society of Hematology we provided a comprehensive characterization of the various driving genetic alterations that led to the constitutive activation of STAT3 in ALK-ALCL.

This characterization was reached by combining Whole Exome Sequencing (WES), Copy Number Variation analysis and RNAseq in a discovery panel (5 ALK+ and 18 ALK- ALCL). The frequency of JAK/STAT3 mutations was further tested by Sanger and deep sequencing analyses, in an independent panel of 158 ALCL (88 ALK-, 26 ALK+ ALCL and 44cALCL) AND 67 PTCL. Functional tests were completed by transfection/transduction of different cells lines (STAT3 -/- MEF, HEK-293T, SUPM2 TTA and SUPM2 S3S), in association with Western Blot, and using cells viability analyses, Luciferase Assay, 2D and soft agar colony assays.

From the gathered data we were able to demonstrate that a subset of ALK-ALCL displays the constitutive activation of JAK/STAT3 pathway via multiple mechanisms. These mechanisms could be significantly abrogated by specific inhibitors like JAK1/2 and ROS1. With the central role of STAT3 there is the possibility of using novel targeting strategies to provide new avenues for the treatment of ALK- ALCL patients as suggested in our preclinical ALC PDT model.

Integrin αvβ3 Presents a Possible Therapeutic Target for Patients with T-cell Lymphomas

lecBy Leandro Cerchietti, MD

Malignant T-cell proliferation, survival, and drug resistance are dependent on a combination of external stimuli delivered by the micro-environment. Previous research has shown that the transmembrane receptor integrin αvβ3 plays a crucial role in mediating the interaction of T-cell lymphoma (TCL) cells with external signals. Integrin αvβ3 ligands include extracellular matrix-associated signaling proteins and soluble factors such as thyroid hormones (TH). Having previously shown that TH stimulate the proliferation of TCL through complimentary intracellular pathways involving the αvβ3 integrin, we hypothesized that targeting integrin αvβ3 could represent a novel strategy in treating TCL patients in an abstract presented during ASH.

In determining whether αVβ3 integrin is of therapeutic benefit for TCL, xenografts were developed in SCID mice using CUTLL1 cells transfected with si-control, si-αV and si-β3, and monitored tumor growth and angiogenesis. CUTLL1 was found to transfect with si-αV and si-β3 developed significant smaller tumors than si-control. The translational impact of this strategy was determined through the effect of cilengitide, a selective αVβ3 integrin inhibitor in phase 3 for glioma, in pre-clinical models of PTCL-NOS,  ALCL-ALK+ and  ALCL-ALK-. Similarly to si-αV and si-β3 treated mice, the anti-lymphoma effect of cilengitide correlated with lower levels of angiogenesis and NFkB activation.

This allowed us to elucidate the mechanisms by which integrin αvβ3 activation increases TCL proliferation through the activation of pro-survival pathways in malignant T-cells, while promoting angiogenesis. In the course of our research we also found that the genetic and pharmacological targeting of integrin αvβ3 induces an anti-lymphoma effect in TCL, including ALCL-ALK + and ALCL-ALK- PDT models obtained from treatment refractory patients. Both of these findings present potentially new therapeutic targets for the treatment of patients with T-cell lymphoma.