Over-expression of proteasome 26S subunit, non-ATPase 14 in human endometrial cancer.

Gynecologic cancers including cancers of the endometrium are a clinical problem (1-4). We mined published microarray data (5, 6) to discover genes associated with endometrial cancers by comparing transcriptomes of the normal and hyperplastic endometrium to endometrial tumors from humans. We identified proteasome 26S subunit, non-ATPase 14, encoded by PSMD14, as among the most differentially expressed genes, transcriptome-wide, in cancers of the endometrium. PSMD14 was expressed at significantly higher levels in endometrial tumor tissues as compared to the endometrium. Importantly, in human endometrial cancer, primary tumor expression of PSMD14 was correlated with overall survival in white patients with low mutational burden. PSMD14 may be a molecule of interest in understanding the etiology or progression of human endometrial cancer.

Effects of Telmisartan on Myocardial Protein Profiles in Hypertensive Rats

Background To investigate the effects of telmisartan on the protein profiles of the left ventricular myocardium in spontaneously hypertensive rats (SHR). Methods Sixteen SHR were randomly divided into control and telmisartan treatment groups. Rats were treated with sterile water (10 ml/kg) or telmisartan (4.33 mg/kg) by gavage for 12 weeks. Wistar-Kyoto (WKY) rats treated with sterile water (10 ml/kg) as controls. At the end of 12 weeks of control or telmisartan treatment, rats were sacrificed, and hearts were collected for protein preparations, isotope labeling, and mass spectrometric analysis. Results In total, there were 23 differentially expressed proteins in the left ventricular myocardium between control and telmisartan treatment groups in SHR. Compared with the telmisartan group, the upregulated proteins in the SHR were dual-specificity mitogen-activated protein kinase kinase 3-like, transgelin, and haptoglobin subtype 2. The downregulated proteins in the SHR were as follows: von Willebrand factor (fragment), kininogen 1, small ribonucleoprotein-related protein, fibrinogen beta chain, protein mass 3 (fragment), proteasome 26s, heat shock protein 27-related protein 1, tenascin X, fibronectin subtype 2, transferrin receptor protein, platelets 1, cathepsin L1, complement factor B, isoform CRA_b, fibrinogen isomer, immunoglobulin heavy chain (γ polypeptide), and α 1 antiprotease. Conclusions Telmisartan differentially regulates myocardial protein expression in hypertensive rats including heat shock protein 27, fibrinogen, fibronectin, proteasome 26s, and transgelin, as well as proteins in biochemical, metabolic, and signal transduction pathways. These changes in protein expression may contribute to the antihypertrophic effects of telmisartan in hypertension.

Proteasome 26S subunit, non-ATPases 1 (PSMD1) and 3 (PSMD3), play an oncogenic role in chronic myeloid leukemia by stabilizing nuclear factor-kappa B

Tyrosine kinase inhibitors (TKIs) targeting BCR-ABL1 have revolutionized therapy for chronic myeloid leukemia (CML), paving the way for clinical development in other diseases. Despite success, targeting leukemic stem cells and overcoming drug resistance remain challenges for curative cancer therapy. To identify drivers of kinase-independent TKI resistance in CML, we performed genome-wide expression analyses on TKI-resistant versus sensitive CML cell lines, revealing a nuclear factor-kappa B (NF-κB) expression signature. Nucleocytoplasmic fractionation and luciferase reporter assays confirmed increased NF-κB activity in the nucleus of TKI-resistant versus sensitive CML cell lines and CD34+ patient samples. Two genes that were upregulated in TKI-resistant CML cells were proteasome 26S subunit, non-ATPases 1 (PSMD1) and 3 (PSMD3), both members of the 19S regulatory complex in the 26S proteasome. PSMD1 and PSMD3 were also identified as survival-critical genes in a published small hairpin RNA library screen of TKI resistance. We observed markedly higher levels of PSMD1 and PSMD3 mRNA in CML patients who had progressed to the blast phase compared with the chronic phase of the disease. Knockdown of PSMD1 or PSMD3 protein correlated with reduced survival and increased apoptosis in CML cells, but not in normal cord blood CD34+ progenitors. Luciferase reporter assays and immunoblot analyses demonstrated that PSMD1 and PSMD3 promote NF-κB protein expression in CML, and that signal transducer and activator of transcription 3 (STAT3) further activates NF-κB in scenarios of TKI resistance. Our data identify NF-κB as a transcriptional driver in TKI resistance, and implicate PSMD1 and PSMD3 as plausible therapeutic targets worthy of future investigation in CML and possibly other malignancies.

Effects of Telmisartan on Myocardial Protein Profiles in Hypertensive Rats

Background To investigate the effects of telmisartan on the protein profiles of the left ventricular myocardium in spontaneously hypertensive rats (SHR). Methods Sixteen SHR were randomly divided into control and telmisartan treatment groups. Rats were treated with sterile water (10 ml/kg) or telmisartan (4.33 mg/kg) by gavage for 12 weeks. Wistar-Kyoto (WKY) rats treated with sterile water (10 ml/kg) as controls. At the end of 12 weeks of control or telmisartan treatment, rats were sacrificed, and hearts were collected for protein preparations, isotope labeling, and mass spectrometric analysis. Results In total, there were 23 differentially expressed proteins in the left ventricular myocardium between control and telmisartan treatment groups in SHR. Compared with the telmisartan group, the upregulated proteins in the SHR were dual-specificity mitogen-activated protein kinase kinase 3-like, transgelin, and haptoglobin subtype 2. The downregulated proteins in the SHR were as follows: von Willebrand factor (fragment), kininogen 1, small ribonucleoprotein-related protein, fibrinogen beta chain, protein mass 3 (fragment), proteasome 26s, heat shock protein 27-related protein 1, tenascin X, fibronectin subtype 2, transferrin receptor protein, platelets 1, cathepsin L1, complement factor B, isoform CRA_b, fibrinogen isomer, immunoglobulin heavy chain (γ polypeptide), and α 1 antiprotease. Conclusions Telmisartan differentially regulates myocardial protein expression in hypertensive rats including heat shock protein 27, fibrinogen, fibronectin, proteasome 26s and transgelin, as well as proteins in biochemical, metabolic, and signal transduction pathways. These changes in protein expression may contribute to the antihypertrophic effects of telmisartan in hypertension.

Dégradation induite des protéines par des molécules PROTAC et stratégies apparentées : développements à visée thérapeutique

Alors que, pour la plupart, les médicaments actuels sont de petites molécules inhibant l’action d’une protéine en bloquant un site d’interaction, la dégradation ciblée des protéines, découverte il y a une vingtaine d’années via les petites molécules PROTAC, connaît aujourd’hui un très grand développement, aussi bien au niveau universitaire qu’industriel. Cette dégradation ciblée permet de contrôler la concentration intracellulaire d’une protéine spécifique comme peuvent le faire les techniques basées sur les acides nucléiques (oligonucléotides antisens, ARNsi, CRISPR-Cas9). Les molécules PROTAC sont des chimères hétéro-bifonctionnelles capables de lier simultanément une protéine spécifique devant être dégradée et une E3 ubiquitine ligase. Les PROTAC sont donc capables de provoquer l’ubiquitinylation de la protéine ciblée et sa dégradation par le protéasome 26S. De nature peptidique, puis non peptidique, les PROTAC sont maintenant administrables par voie orale. Ce détournement du système ubiquitine protéasome permet aux molécules PROTAC d’élargir considérablement le champ des applications thérapeutiques puisque l’élimination de protéines dépourvues de poches ou de crevasses bien définies, dites difficiles à cibler, devient possible. Cette technologie versatile a conduit à la dégradation d’une grande variété de protéines comme des facteurs de transcription, des sérine/thréonine/tyrosine kinases, des protéines de structure, des protéines cytosoliques, des lecteurs épigénétiques. Certaines ligases telles que VHL, MDM2, cereblon et IAP sont couramment utilisées pour être recrutées par les PROTAC. Actuellement, le nombre de ligases pouvant être utilisées ainsi que la nature des protéines dégradées sont en constante augmentation. Deux PROTAC sont en étude clinique pour les cancers du sein (ARV471) et de la prostate (ARV110). La dégradation spécifique d’une protéine par le protéasome peut aussi être induite par d’autres types de molécules synthétiques : colles moléculaires, marqueurs hydrophobes, HaloPROTAC, homo-PROTAC. D’autres constituants cellulaires sont aussi éligibles à une dégradation induite : ARN-PROTAC pour les protéines se liant à l’ARN et RIBOTAC pour la dégradation de l’ARN lui-même comme celui du SARS-CoV-2. Des dégradations induites en dehors du protéasome sont aussi connues : LYTAC, pour des chimères détournant la dégradation de protéines extracellulaires vers les lysosomes, et MADTAC, pour des chimères détournant la dégradation par macroautophagie. Plusieurs techniques, en particulier des plates-formes de criblage, la modélisation mathématique et la conception computationnelle sont utilisées pour le développement de nouveaux PROTAC efficaces.