An efficient method for the C-N cross-coupling of (hetero)aryl (pseudo)halides with optically pure alpha-amino acid esters employing a commercially available nickel catalyst and weak inorganic base ...was developed. This is the first example of Nicatalyzed N-arylation of amino acid esters without the use of electrochemistry, which was shown to effectively couple a variety of amino acid tert-butyl esters with (hetero)aryl chlorides, bromides, and tosylates in high yields and excellent enantioretention. Base-mediated racemization was revealed during control experiments, but increasing the steric bulk of the amino acid ester group limited the amount of racemization of the product.
Arginine methyltransferases critically regulate cellular homeostasis by modulating the functional outcome of their substrates. The protein arginine methyltransferase 5 (PRMT5) is an enzyme involved ...in growth and survival pathways promoting tumorigenesis. However, little is known about the biologic function of PRMT5 and its therapeutic potential in multiple myeloma (MM). In the present study, we identified and validated PRMT5 as a new therapeutic target in MM. PRMT5 is overexpressed in patient MM cells and associated with decreased progression-free survival and overall survival. Either genetic knockdown or pharmacological inhibition of PRMT5 with the inhibitor EPZ015666 significantly inhibited growth of both cell lines and patient MM cells. Furthermore, PRMT5 inhibition abrogated NF-κB signaling. Interestingly, mass spectrometry identified a tripartite motif-containing protein 21 TRIM21 as a new PRMT5-partner, and we delineated a TRIM21-dependent mechanism of NF-κB inhibition. Importantly, oral administration of EPZ015666 significantly decreased MM growth in a humanized murine model of MM. These data both demonstrate the oncogenic role and prognostic relevance of PRMT5 in MM pathogenesis, and provide the rationale for novel therapies targeting PRMT5 to improve patient outcome.
Interferon regulatory factor 4 (IRF4) is an attractive therapeutic target in multiple myeloma (MM). We here report that expression of IRF4 mRNA inversely correlates with microRNA (miR)-125b in MM ...patients. Moreover, we provide evidence that miR-125b is downregulated in TC2/3 molecular MM subgroups and in established cell lines. Importantly, constitutive expression of miR-125b-5p by lentiviral vectors or transfection with synthetic mimics impaired growth and survival of MM cells and overcame the protective role of bone marrow stromal cells in vitro. Apoptotic and autophagy-associated cell death were triggered in MM cells on miR-125b-5p ectopic expression. Importantly, we found that the anti-MM activity of miR-125b-5p was mediated via direct downregulation of IRF4 and its downstream effector BLIMP-1. Moreover, inhibition of IRF4 translated into downregulation of c-Myc, caspase-10 and cFlip, relevant IRF4-downstream effectors. Finally, in vivo intra-tumor or systemic delivery of formulated miR-125b-5p mimics against human MM xenografts in severe combined immunodeficient/non-obese diabetic mice induced significant anti-tumor activity and prolonged survival. Taken together, our findings provide evidence that miR-125b, differently from other hematologic malignancies, has tumor-suppressor activity in MM. Furthermore, our data provide proof-of-concept that synthetic miR-125b-5p mimics are promising anti-MM agents to be validated in early clinical trials.
Despite therapeutic advances, multiple myeloma (MM) remains an incurable disease, predominantly because of the development of drug resistance. The activator protein-1 (AP-1) transcription factor ...family has been implicated in a multitude of physiologic processes and tumorigenesis; however, its role in MM is largely unknown. Here we demonstrate specific and rapid induction of the AP-1 family member JunB in MM cells when co-cultured with bone marrow stromal cells. Supporting a functional key role of JunB in MM pathogenesis, knockdown of JUNB significantly inhibited in vitro MM cell proliferation and survival. Consistently, induced silencing of JUNB markedly decreased tumor growth in a murine MM model of the microenvironment. Subsequent gene expression profiling revealed a role for genes associated with apoptosis, DNA replication and metabolism in driving the JunB-mediated phenotype in MM cells. Importantly, knockdown of JUNB restored the response to dexamethasone in dexamethasone-resistant MM cells. Moreover, 4-hydroxytamoxifen-induced activation of a JunB-ER fusion protein protected dexamethasone-sensitive MM cells against dexamethasone- and bortezomib-induced cytotoxicity. In summary, our results demonstrate for the first time a specific role for AP-1/JunB in MM cell proliferation, survival and drug resistance, thereby strongly supporting that this transcription factor is a promising new therapeutic target in MM.
Pertuzumab plus trastuzumab provides a more comprehensive blockade of HER2 signalling than trastuzumab alone. Therefore, we conducted a phase IIa study of the pharmacokinetics and safety of ...pertuzumab plus trastuzumab and chemotherapy in advanced gastric cancer (aGC).
Patients received pertuzumab 840 mg for cycle 1 and 420 mg q3w for cycles 2-6 (Arm A) or pertuzumab 840 mg q3w for six cycles (Arm B). Trastuzumab, cisplatin and capecitabine were also given for six cycles, then trastuzumab q3w until disease progression or unmanageable toxicity. The co-primary endpoints were day 43 pertuzumab serum trough concentration (Cmin) and safety.
Thirty patients were randomised. Mean pertuzumab Cmin at day 43 was 40.0 μg ml(-1) (s.d.: 17.3) in Arm A and 62.7 μg ml(-1) (29.1) in Arm B. Mean day 43 Cmin in Arm A was ~37% lower than that seen in metastatic breast cancer. The safety profiles were similar between arms and treatment was well tolerated. Partial responses were achieved by 86% and 55% of patients in Arms A and B, respectively.
On the basis of the pharmacokinetic and safety data, the 840 mg q3w pertuzumab dose has been selected for a phase III study of pertuzumab, trastuzumab and chemotherapy in HER2-positive aGC.
•An ion-pair reversed-phase LC–MS/MS method for the determination of LNA-i-miR-221, a 13-mer oligonucleotide, in rat plasma was developed and validated.•LNA-i-miR-221 was extracted from rat plasma by ...LLE followed by SPE; the combination of these two automated procedures proved to be highly effective with quantitative extraction efficiency.•The method validated over the range 10–10000 ng/mL proved to be precise, accurate and selective.•This method was successfully applied to measure the concentrations of LNA-i-miR-221 in plasma samples following the intravenous administration during a 4-week toxicity study in rats.
LNA-i-miR-221, a 13-mer oligonucleotide, is a new miR-221 inhibitor that could be used as a novel drug for multiple myeloma. Herein, an ion-pair reversed phase liquid chromatography–tandem mass spectrometry (LC–MS/MS) method has been developed and validated for the quantification of LNA-i-miR-221 in rat plasma. Plasma samples were prepared with an initial phenol/chloroform/isoamyl alcohol liquid–liquid extraction followed by a solid phase extraction. Chromatographic separation was performed with a gradient system on a HALO C18 column using hexafluoro-2-propanol/triethylamine buffer and methanol as mobile phase at a flow rate of 0.4 mL/min. Under these conditions LNA-i-miR-221 and the analogue internal standard are co-eluted at 1.2 min. The detection was carried out in multiple reaction monitoring (MRM) mode using a negative electrospray ionization (ESI) interface. The assay showed a good linearity within the calibration range 10–10000 ng/mL. The precision, accuracy, and recovery values were found to be <15% (<20% at LLOQ), 100 ± 15%, and 97.6–103.7%, respectively. This method was successfully applied to measure the concentrations of LNA-i-miR-221 in plasma samples following the intravenous administration during a 4-week toxicity study in rats.
Dendritic cells (DCs) have a key role in regulating tumor immunity, tumor cell growth and drug resistance. We hypothesized that multiple myeloma (MM) cells might recruit and reprogram DCs to a ...tumor-permissive phenotype by changes within their microRNA (miRNA) network. By analyzing six different miRNA-profiling data sets, miR-29b was identified as the only miRNA upregulated in normal mature DCs and significantly downregulated in tumor-associated DCs. This finding was validated in primary DCs co-cultured in vitro with MM cell lines and in primary bone marrow DCs from MM patients. In DCs co-cultured with MM cells, enforced expression of miR-29b counteracted pro-inflammatory pathways, including signal transducer and activator of transcription 3 and nuclear factor-κB, and cytokine/chemokine signaling networks, which correlated with patients' adverse prognosis and development of bone disease. Moreover, miR-29b downregulated interleukin-23 in vitro and in the SCID-synth-hu in vivo model, and antagonized a Th17 inflammatory response. All together, these effects translated into strong anti-proliferative activity and reduction of genomic instability of MM cells. Our study demonstrates that MM reprograms the DCs functional phenotype by downregulating miR-29b whose reconstitution impairs DCs ability to sustain MM cell growth and survival. These results underscore miR-29b as an innovative and attractive candidate for miRNA-based immune therapy of MM.
The use of (L)Ni(o-tolyl)Cl precatalysts (L = PAd-DalPhos or CyPAd-DalPhos) enables the C(sp 2)–O cross-coupling of primary, secondary, or tertiary aliphatic alcohols with (hetero)aryl ...electrophiles, including unprecedented examples of such nickel-catalyzed transformations employing (hetero)aryl chlorides, sulfonates, and pivalates. In addition to offering a competitive alternative to palladium catalysis, this work establishes the feasibility of utilizing ancillary ligation as a complementary means of promoting challenging nickel-catalyzed C(sp 2)–O cross-couplings, without recourse to precious-metal photoredox catalytic methods.
MicroRNAs (miRNAs) recently emerged with a key role in multiple myeloma (MM) pathophysiology and are considered important regulators of MM cell growth and survival. Since miRNAs can act either as ...oncogenes or tumour suppressors, the potential of targeting the miRNA network arises as a novel therapeutic approach for human cancer. Potential strategies based on miRNA therapeutics basically rely on miRNA inhibition or miRNA replacement approaches and take benefit respectively from the use of antagomirs or synthetic miRNAs as well as from lipid-based nanoparticles which allow an efficient miRNA-delivery. The availability of experimental in vivo platforms which recapitulate the growth of MM cells within the specific human bone marrow microenvironment in immunocompromised mice (SCID-hu and SCID-synth-hu) provides powerful systems for development of miRNA-based therapeutics in MM. Preliminary findings on the anti-MM activity of synthetic miRNAs in such experimental models offer a proof-of-principle that miRNA therapeutics is a promising opportunity for this still incurable disease representing the rationale for a new venue of investigation in this specific field.
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