Early-onset emphysema attributed to α-1 antitrypsin deficiency (AATD) is frequently overlooked and undertreated. RAPID-RCT/RAPID-OLE, the largest clinical trials of purified human α-1 proteinase inhibitor (A1 -PI; 60 mg kg-1  week-1 ) therapy completed to date, demonstrated for the first time that A1 -PI is clinically effective in slowing lung tissue loss in AATD. A posthoc pharmacometric analysis was undertaken to further explore dose, exposure and response.

Chronic lymphocytic leukemia (CLL) cells possess regulatory functions comparable to those of normal B10 cells, a regulatory B cell subset that suppresses effector T-cell function through STAT3-mediated IL-10 production. However, the mechanisms governing IL-10 production by CLL cells are not fully understood. Here, we show that the CXC chemokine ligand 12 (CXCL12)-CXCR4-STAT3 axis regulates IL-10 production by CLL cells and their ability to suppress T-cell effector function through an IL-10 mediated mechanism. Knockdown of STAT3 significantly impaired the ability of CLL cells to produce IL-10. Furthermore, experiments to assess the role of lenalidomide, an immunomodulatory agent with direct antitumor effect as well as pleiotropic activity on the immune system, showed that this agent prevents a CXCL12-induced increase in p-S727-STAT3 and the IL-10 response by CLL cells. Lenalidomide also suppressed IL-10-induced Y705-STAT3 phosphorylation in healthy T cells, thus reversing CLL-induced T-cell dysfunction. We conclude that the capacity of CLL cells to produce IL-10 is mediated by the CXCL12-CXCR4-STAT3 pathway and likely contributes to immunodeficiency in patients. Lenalidomide appears to be able to reverse CLL-induced immunosuppression through including abrogation of the CXCL12-CXCR4-S727-STAT3-mediated IL-10 response by CLL cells and prevention of IL-10-induced phosphorylation of Y705-STAT3 in T cells.

Protein expression for 384 total and post-translationally modified proteins was assessed in 871 CLL and MSBL patients and was integrated with clinical data to identify strategies for improving diagnostics and therapy, making this the largest CLL proteomics study to date. Proteomics identified six recurrent signatures that were highly prognostic of survival and time to first or second treatment at three levels: individual proteins, when grouped into 40 functionally related groups (PFGs), and systemically in signatures (SGs). A novel SG characterized by hairy cell leukemia like proteomics but poor therapy response was discovered. SG membership superseded other prognostic factors (Rai Staging, IGHV Status) and were prognostic for response to modern (BTK inhibition) and older CLL therapies. SGs and PFGs membership provided novel drug targets and defined optimal candidates for Watch and Wait vs. early intervention. Collectively proteomics demonstrates promise for improving classification, therapeutic strategy selection, and identifying novel therapeutic targets.

Although several studies established that unlike normal B cells chronic lymphocytic leukemia (CLL) cells metabolize fatty acids (FA), how CLL cells internalize FA is poorly understood. Because in various cell types CD36 facilitates FA uptake, we wondered whether a similar mechanism is operative CLL. We found that CD36 levels are higher in CLL cells than in normal B cells, and that small interfering RNA, CD36 neutralizing antibodies or sulfosuccinimidyl oleate (SSO) that inhibits CD36 significantly reduced the oxygen consumption of CLL cells incubated with FA. Because CD36 is oeverexpressed and STAT3 is constitutively activated in CLL cells, we wondered whether STAT3 induces CD36 expression. Sequence analysis identified putative STAT3 binding sites in the CD36 gene promoter. Chromatin immunoprecipitation and an electrophoretic mobility shift assay revealed that STAT3 binds to the CD36 gene promoter. A luciferase assay and STAT3-small hairpin RNA, that significantly decreased the levels of CD36 in CLL cells, established that STAT3 activates the transcription of the CD36 gene. Furthermore, SSO induced a dose-dependent apoptosis of CLL cells. Taken together, our data suggest that STAT3 activates CD36 and that CD36 facilitates FA uptake in CLL cells. Whether CD36 inhibition would provide clinical benefits in CLL remains to be determined.

Richter Transformation (RT) develops in CLL as an aggressive, therapy-resistant, diffuse large B cell lymphoma (RT-DLBCL), commonly clonally-related (CLR) to the concomitant CLL. Lack of available pre-clinical human models has hampered the development of novel therapies for RT-DLBCL. Here, we report the profiles of genetic alterations, chromatin accessibility and active enhancers, gene-expressions and anti-lymphoma drug-sensitivity of three newly established, patient-derived, xenograft (PDX) models of RT-DLBCLs, including CLR and clonally-unrelated (CLUR) to concomitant CLL. The CLR and CLUR RT-DLBCL cells display active enhancers, higher single-cell RNA-Seq-determined mRNA, and protein expressions of IRF4, TCF4, and BCL2, as well as increased sensitivity to BET protein inhibitors. CRISPR knockout of IRF4 attenuated c-Myc levels and increased sensitivity to a BET protein inhibitor. Co-treatment with BET inhibitor or BET-PROTAC and ibrutinib or venetoclax exerted synergistic in vitro lethality in the RT-DLBCL cells. Finally, as compared to each agent alone, combination therapy with BET-PROTAC and venetoclax significantly reduced lymphoma burden and improved survival of immune-depleted mice engrafted with CLR-RT-DLBCL. These findings highlight a novel, potentially effective therapy for RT-DLBCL.

Malignancies can become reliant on glutamine as an alternative energy source and as a facilitator of aberrant DNA methylation, thus implicating glutaminase (GLS) as a potential therapeutic target. We demonstrate preclinical synergy of telaglenastat (CB-839), a selective GLS inhibitor, when combined with azacytidine (AZA), in vitro and in vivo , followed by a phase Ib/II study of the combination in patients with advanced MDS. Treatment with telaglenastat/AZA led to an ORR of 70% with CR/mCRs in 53% patients and a median overall survival of 11.6 months. scRNAseq and flow cytometry demonstrated a myeloid differentiation program at the stem cell level in clinical responders. Expression of non-canonical glutamine transporter, SLC38A1, was found to be overexpressed in MDS stem cells; was associated with clinical responses to telaglenastat/AZA and predictive of worse prognosis in a large MDS cohort. These data demonstrate the safety and efficacy of a combined metabolic and epigenetic approach in MDS.

Signal transducer and activator of transcription (STAT)-3 might be phosphorylated or acetylated. Unlike the phosphorylation of STAT3, little is known about the acetylation of STAT3 in chronic lymphocytic leukemia (CLL) cells. Because acetylation activates STAT3 transcription, we sought to study the acetylation status of STAT3 in CLL cells. Using Western immunoblotting, immunoprecipitation, and flow cytometry we found that, apart from its constitutive serine phosphorylation, STAT3 is constitutively acetylated on lysine 685 residues. Because the acetyltransferase p300 was found to acetylate STAT3 on lysine 685 residues, we wondered whether p300 acetylates STAT3 in CLL cells. Using Western immunoblotting we detected high levels of p300 protein in CLL but not normal B cells. Transfection of CLL cells with p300 small-interfering (si) RNA downregulated p300 transcripts as well as p300 and acetyl-STAT3 protein levels. In addition, p300 siRNA attenuated STAT3-DNA binding and downregulated mRNA levels of STAT3-regulated genes. Furthermore, transfection of CLL cells with p300-siRNA induced a 3-fold increase in the rate of spontaneous apoptosis. Taken together, our data suggest that in CLL cells STAT3 p300 induces constitutive acetylation and activation of STAT3. Whether inhibition of STAT3 acetylation might provide clinical benefit in patients with CLL remains to be determined.

DNA damage response (DNADR) recognition and repair (DDR) pathways affect carcinogenesis and therapy responsiveness in cancers, including leukemia. We measured protein expression levels of 16 DNADR and DDR proteins using the Reverse Phase Protein Array methodology in acute myeloid (AML) (n = 1310), T-cell acute lymphoblastic leukemia (T-ALL) (n = 361) and chronic lymphocytic leukemia (CLL) (n = 795) cases. Clustering analysis identified five protein expression clusters; three were unique compared to normal CD34+ cells. Individual protein expression differed by disease for 14/16 proteins, with five highest in CLL and nine in T-ALL, and by age in T-ALL and AML (six and eleven proteins, respectively), but not CLL (n = 0). Most (96%) of the CLL cases clustered in one cluster; the other 4% were characterized by higher frequencies of deletion 13q and 17p, and fared poorly (p < 0.001). T-ALL predominated in C1 and AML in C5, but both occurred in all four acute-dominated clusters. Protein clusters showed similar implications for survival and remission duration in pediatric and adult T-ALL and AML populations, with C5 doing best in all. In summary, DNADR and DDR protein expression was abnormal in leukemia and formed recurrent clusters that were shared across the leukemias with shared prognostic implications across diseases, and individual proteins showed age- and disease-related differences.