Epigenetic regulation enables tumors to respond to changing environments during tumor progression and metastases and facilitates treatment resistance. Targeting chromatin modifiers or catalytic ...effectors of transcription is an emerging anti-cancer strategy. The cyclin-dependent kinases (CDKs) 12 and 13 phosphorylate the C-terminal domain of RNA polymerase II, regulating transcription and co-transcriptional processes. Here we report the development of SR-4835, a highly selective dual inhibitor of CDK12 and CDK13, which disables triple-negative breast cancer (TNBC) cells. Mechanistically, inhibition or loss of CDK12/CDK13 triggers intronic polyadenylation site cleavage that suppresses the expression of core DNA damage response proteins. This provokes a “BRCAness” phenotype that results in deficiencies in DNA damage repair, promoting synergy with DNA-damaging chemotherapy and PARP inhibitors.
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•SR-4835, a potent dual inhibitor of CDK12/CDK13, provokes TNBC cell death•CDK12/CDK13 inhibition/loss promotes cleavage at intronic polyadenylation sites•CDK12 inhibition causes a BRCAness phenotype by blocking homologous recombination•SR-4835 acts in synergy with DNA-damaging chemotherapy and PARP inhibitors
Quereda et al. develop a selective dual CDK12/CDK13 inhibitor that reduces the expression of core DNA damage response genes by increasing intronic polyadenylation site cleavage, resulting in DNA damage repair deficiency and conferring sensitivity to DNA-damaging agents and PARP inhibitors.
A reverse pH gradient is a hallmark of cancer metabolism, manifested by extracellular acidosis and intracellular alkalization. While consequences of extracellular acidosis are known, the roles of ...intracellular alkalization are incompletely understood. By reconstructing and integrating enzymatic pH-dependent activity profiles into cell-specific genome-scale metabolic models, we develop a computational methodology that explores how intracellular pH (pHi) can modulate metabolism. We show that in silico, alkaline pHi maximizes cancer cell proliferation coupled to increased glycolysis and adaptation to hypoxia (i.e., the Warburg effect), whereas acidic pHi disables these adaptations and compromises tumor cell growth. We then systematically identify metabolic targets (GAPDH and GPI) with predicted amplified anti-cancer effects at acidic pHi, forming a novel therapeutic strategy. Experimental testing of this strategy in breast cancer cells reveals that it is particularly effective against aggressive phenotypes. Hence, this study suggests essential roles of pHi in cancer metabolism and provides a conceptual and computational framework for exploring pHi roles in other biomedical domains.
Nucleophilic Phosphine Organocatalysis Methot, Joey L.; Roush, William R.
Advanced synthesis & catalysis,
08/2004, Letnik:
346, Številka:
9-10
Journal Article
Recenzirano
Odprti dostop
Phosphines have recently become popular choices as nucleophilic catalysts in organic synthesis. The unique reactivity of phosphines compared to amines has allowed the discovery of new nucleophilic ...addition reactions at the α‐ and γ‐positions of unsaturated carbonyl compounds, as well as novel 3+2 and 4+2 cycloaddition reactions of activated alkynes and alkenes. The accessibility of chiral phosphines has rendered several of these transformations enantioselective and has made possible the kinetic resolution of racemic secondary alcohols by phosphine‐catalyzed acylation. This mini‐review presents recent advances in nucleophilic phosphine organocatalysis for carbon‐carbon bond formation.
Chiral Brønsted acid catalyzed asymmetric allenylboration reactions are described. Under optimized conditions, anti-homopropargyl alcohols 2 are obtained in high yields with excellent diastereo- and ...enantioselectivities from stereochemically matched aldehyde allenylboration reactions with (M)-1 catalyzed by the chiral phosphoric acid (S)-4. The syn-isomers 3 can also be obtained in good diastereoselectivities and excellent enantioselectivities from the mismatched allenylboration reactions of aromatic aldehydes using (M)-1 in the presence of the enantiomeric phosphoric acid (R)-4. The stereochemistry of the methyl group introduced into 2 and 3 is controlled by the chirality of the allenylboronate (M)-1, whereas the configuration of the new hydroxyl stereocenter is controlled by the enantioselectivity of the chiral phosphoric acid catalyst used in these reactions. The synthetic utility of this methodology was further demonstrated in highly diastereoselective syntheses of a variety of anti, anti-stereotriads, the direct synthesis of which has constituted a significant challenge using previous generations of aldol and crotylmetal reagents.
Current strategies to produce homogeneous antibody-drug conjugates (ADCs) rely on mutations or inefficient conjugation chemistries. Here we present a strategy to produce site-specific ADCs using a ...highly reactive natural buried lysine embedded in a dual variable domain (DVD) format. This approach is mutation free and drug conjugation proceeds rapidly at neutral pH in a single step without removing any charges. The conjugation chemistry is highly robust, enabling the use of crude DVD for ADC preparation. In addition, this strategy affords the ability to precisely monitor the efficiency of drug conjugation with a catalytic assay. ADCs targeting HER2 were prepared and demonstrated to be highly potent and specific in vitro and in vivo. Furthermore, the modular DVD platform was used to prepare potent and specific ADCs targeting CD138 and CD79B, two clinically established targets overexpressed in multiple myeloma and non-Hodgkin lymphoma, respectively.
Kinetically controlled hydroboration of allenylboronate 5 followed by double allylboration with the resulting allylborane (Z)-7 gave (Z)-2-methyl-1,5-anti-pentenediols 6 in good yield and high ...enantioselectivity in the presence of 10% BF3·OEt2 as the catalyst in the second allylboration step. Under thermodynamically controlled isomerization conditions, (Z)-7 can readily isomerize to (E)-7. Double allylboration of representative aldehydes with allylborane (E)-7 gave (E)-2-methyl-1,5-anti-pentenediols 4 in good yield and high enantioselectivity without requiring use of the BF3·OEt2 catalyst. Thus, 2-methyl-1,5-anti-pentenediols with either olefin geometry can be synthesized from the same allenylboronate precursor 5. Furthermore, 1,5-pentenediols 4 and 6 can be easily converted to 1,3,5-triols with excellent diastereoselectivity in one step.
A stereoselective synthesis of trans-1,2,3,6-tetrahydropyridines 8 is described. This synthesis proceeds via intramolecular Mistunobu reactions of 1,5-syn-(Z)-amino alcohols 7, which were prepared by ...a highly diastereo- and enantioselective double-allylboration reaction of aldehyde 5 and silylimine 6. The chiral bifunctional γ-borylallylborane 9 E was generated in situ by hydroboration of allene 3 with (diisopinocampheyl)borane 4. This strategy was applied to the total synthesis of andrachcine 1, thus establishing with certainty the absolute and relative configuration of the natural product.
Myc oncoproteins induce genes driving aerobic glycolysis, including lactate dehydrogenase-A that generates lactate. Here, we report that Myc controls transcription of the lactate transporter ...SLC16A1/MCT1 and that elevated MCT1 levels are manifest in premalignant and neoplastic Eμ-Myc transgenic B cells and in human malignancies with MYC or MYCN involvement. Notably, disrupting MCT1 function leads to an accumulation of intracellular lactate that rapidly disables tumor cell growth and glycolysis, provoking marked alterations in glycolytic intermediates, reductions in glucose transport, and in levels of ATP, NADPH, and ultimately, glutathione (GSH). Reductions in GSH then lead to increases in hydrogen peroxide, mitochondrial damage, and ultimately, cell death. Finally, forcing glycolysis by metformin treatment augments this response and the efficacy of MCT1 inhibitors, suggesting an attractive combination therapy for MYC/MCT1-expressing malignancies.
The stereocontrolled synthesis of the β-branched anti,anti-dipropionate stereotriad 4 via aldol or crotylmetal chemistry represents a historical challenge to the organic synthesis community. Here we ...describe a general solution to the long-standing problem associated with the synthesis of 4 by utilizing mismatched double asymmetric crotylboration reactions of enantioenriched α-methyl substituted aldehydes with the chiral, nonracemic crotylborane reagent (S)-(E)-22 (or its enantiomer). This method not only provides direct access to anti,anti-dipropionate stereotriads 24 a synthetic equivalent of 4 with very good (5–8:1) if not excellent (≥15:1) diastereoselectivity from β-branched chiral aldehydes with ≤50:1 intrinsic diastereofacial selectivity preferences but also provides a vinylstannane unit in the products that is properly functionalized for use in subsequent C–C bond-forming events. We anticipate that this method will be widely applicable and will lead to substantial simplification of strategies for synthesis of polyketide natural products.
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