Paulus, Aneel

AbstractIn a continuing search for curcuminoid (CUR) compounds with antitumor activity, a novel series of heterocyclic CUR–BF2 adducts and CUR compounds based on indole, benzothiophene, and benzofuran along with their aryl pyrazoles were synthesized. Computational docking studies were performed to compare binding efficiency to target proteins involved in specific cancers, namely HER2, proteasome, VEGFR, BRAF, and Bcl‐2, versus known inhibitor drugs. The majority presented very good binding affinities, similar to, and even more favorable than those of known inhibitors. The indole‐based CUR–BF2 and CUR compounds and their bis‐thiocyanato derivatives exhibited high anti‐proliferative and apoptotic activity by in vitro bioassays against a panel of 60 cancer cell lines, more specifically against multiple myeloma (MM) cell lines (KMS11, MM1.S, and RPMI‐8226) with significantly lower IC50 values versus healthy PBMC cells; they also exhibited higher anti‐proliferative activity in human colorectal cancer cells (HCT116, HT29, DLD‐1, RKO, SW837, and Caco2) than the parent curcumin, while showing notably lower cytotoxicity in normal colon cells (CCD112CoN and CCD841CoN).

BACKGROUNDOutcomes have improved significantly in multiple myeloma (MM), but racial disparities in health care access and survival exist. A comprehensive analysis exploring MM care and racial disparities is warranted.METHODSPatients with MM from 1991 to 2010 in the Surveillance, Epidemiology, and End Results‐Medicare database were evaluated for racial trends in clinical myeloma‐defining events (MDEs), the receipt of treatment (drugs and stem cell transplantation; [SCT]), the cost of care, and overall survival (OS).RESULTSAmong 35,842 patients, the frequency of all MDEs at diagnosis increased over time; whereas, in recent years (2006‐2010), all MDEs with the exception of renal dialysis decreased. Blacks had highest rates for all MDEs except bone fractures, which were highest in whites. Over time, the proportion of patients who received any treatment, multiple agents, and SCT increased significantly, and the largest increase was observed in the receipt of immunomodulatory drugs and steroids. There was greater receipt of bortezomib and SCT among whites and blacks and higher receipt of immunomodulatory drugs among Hispanics and Asians (P < .001). Medicare claims were highest during first 6 months after MM diagnosis for blacks and at any time after MM diagnosis for Hispanics. Over time, Medicare claims increased most steadily for Hispanics (P < .001). Hypercalcemia, renal dysfunction, and bone fractures were associated with inferior OS. Blacks and Asians had superior OS compared with whites, but racial differences in OS became less pronounced during 2006 through 2010 (P = .182) compared with prior years (P < .01). Better OS was noted among patients who had higher median incomes.CONCLUSIONSThe current results indicate that there have been significant changes in the management of patients with MM over time and provide an in‐depth understanding of the factors that may help explain racial disparities. Cancer 2018;124:1710‐21. © 2018 American Cancer Society

AbstractOutcomes have improved considerably in multiple myeloma (MM), but disparities among racial‐ethnic groups exist. Differences in utilization of novel therapeutics are likely contributing factors. We explored such differences from the SEER‐Medicare database. A utilization analysis of lenalidomide, thalidomide, bortezomib, and stem cell transplant (SCT) was performed for patients diagnosed with MM between 2007 and 2009, including use over time, use by race, time‐dependent trends for each racial subgroup, and survival analysis. A total of 5338 MM patients were included with median 2.4‐year follow‐up. Within the first year of MM diagnosis, utilization of lenalidomide, bortezomib, SCT, and more than one novel agent increased over time while utilization of thalidomide decreased. There was significantly lower utilization of lenalidomide among African‐Americans (P < 0.01), higher thalidomide use among Hispanics and Asians (P < 0.01), and lower bortezomib use among Asians (P < 0.01). Hispanics had the highest median number of days to first dose of bortezomib (P = 0.02) and the lowest utilization of SCT (P < 0.01). Hispanics and Asians were the only groups without notable increases in lenalidomide and bortezomib use, respectively. SCT utilization increased over time for all except African‐Americans. SCT use within the first year after diagnosis was associated with better overall survival (HR 0.52; 95% CI: 0.4–0.68), while bortezomib use was associated with inferior survival (HR 1.14; 95% CI 1.02–1.28). We noted considerable variability in MM therapeutics utilization with seeming inequity for racial‐ethnic minorities. These trends should be considered to eliminate drug access and utilization disparities and achieve equitable benefit of therapeutic advances across all races.

The ubiquitin–proteasome system (UPS) is increasingly recognized as a therapeutic target for the development of anticancer therapies. The success of the 20S proteasome core particle (20S CP) inhibitor bortezomib in the clinical management of multiple myeloma has raised the possibility of identifying other UPS components for therapeutic intervention. We previously identified the small molecule b‐AP15 as an inhibitor of 19S proteasome deubiquitinase (DUB) activity. Building upon our previous data, we performed a structure–activity relationship (SAR) study on b‐AP15 and identified VLX1570 as an analog with promising properties, including enhanced potency and improved solubility in aqueous solution. In silico modeling was consistent with interaction of VLX1570 with key cysteine residues located at the active sites of the proteasome DUBs USP14 and UCHL5. VLX1570 was found to inhibit proteasome deubiquitinase activity in vitro in a manner consistent with competitive inhibition. Furthermore, using active‐site‐directed probes, VLX1570 also inhibited proteasome DUB activity in exposed cells. Importantly, VLX1570 did not show inhibitory activity on a panel of recombinant non‐proteasome DUBs, on recombinant kinases, or on caspase‐3 activity, suggesting that VLX1570 is not an overtly reactive general enzyme inhibitor. Taken together, our data shows the chemical and biological properties of VLX1570 as an optimized proteasome DUB inhibitor.

SummaryDeubiquitinase enzymes (DUBs) of the proteasomal 19S regulatory particle are emerging as important therapeutic targets in several malignancies. Here we demonstrate that inhibition of two proteasome‐associated DUBs (USP14 and UCHL5) with the small molecule DUB inhibitor b‐AP15, results in apoptosis of human Waldenström macroglobulinaemia (WM) cell lines and primary patient‐derived WM tumour cells. Importantly, b‐AP15 produced proteotoxic stress and apoptosis in WM cells that have acquired resistance to the proteasome inhibitor bortezomib. In silico modelling identified protein residues that were critical for the binding of b‐AP15 with USP14 or UCHL5 and proteasome enzyme activity assays confirmed that b‐AP15 does not affect the proteolytic capabilities of the 20S proteasome β‐subunits. In vitro toxicity from b‐AP15 appeared to result from a build‐up of ubiquitinated proteins and activation of the endoplasmic reticulum stress response in WM cells, an effect that also disrupted the mitochondria. Focused transcriptome profiling of b‐AP15‐treated WM cells revealed modulation of several genes regulating cell stress and NF‐κB signalling, the latter whose protein translocation and downstream target activation was reduced by b‐AP15 in vitro. This is the first report to define the effects and underlying mechanisms associated with inhibition of USP14 and UCHL5 DUB activity in WM tumour cells.

SummaryMultiple myeloma, the second most common haematological malignancy in the U.S., is currently incurable. Disruption of the intrinsic apoptotic pathway by BCL2 and MCL1 upregulation is observed in >80% of myeloma cases and is associated with an aggressive clinical course. Remarkably, there is no approved drug with the ability to target BCL2 or MCL1. Thus, we investigated the anti‐tumour effects of a pan‐BCL2 inhibitor, AT‐101, which has high binding specificity for BCL2 and MCL1 in preclinical models of plasma cell cancers (Multiple myeloma and Waldenström macroglobulinaemia). Gene expression and immunoblot analysis of six plasma cell cancer models showed upregulation of BCL2 family members. AT‐101 was able to downregulate BCL2 and MCL1 in all plasma cell cancer models and induced apoptotic cell death in a caspase‐dependent manner by altering mitochondrial membrane permeability. This cytotoxic effect and BCL2 downregulation were further potentiated when AT‐101 was combined with lenalidomide/dexamethasone (LDA). NanoString nCounter mRNA quantification and Ingenuity Pathways Analysis revealed differential changes in the CCNA2, FRZB, FYN, IRF1, PTPN11 genes in LDA‐treated cells. In summary, we describe for the first time the cellular and molecular events associated with the use of AT‐101 in combination with lenalidomide/dexamethasone in preclinical models of plasma cell malignancy.