Raj Nayan Sewduth

Hypertension-driven vascular remodelling and endothelial dysfunction are key pathological processes underlying cerebral small vessel disease (cSVD), a leading cause of vascular cognitive impairment. Although extracellular matrix (ECM) remodelling is a critical regulator of endothelial behaviour, its mechanistic contribution to hypertension-associated cSVD remains poorly understood. Here, we identify a conserved, disease-associated shift in vascular ECM composition across human vascular dementia datasets and the DOCA-salt model of hypertension, marked by pronounced perivascular accumulation of type I collagen (COL1). Given that hypertension-induced cSVD is characterised by cerebral hypoperfusion, we investigated how ECM remodelling modulates endothelial mechanotransduction under low-flow conditions. Human brain microvascular endothelial cells cultured on COL1 under low shear stress (5 dyn/cm²) exhibited a striking loss of Transforming Growth Factor-β–Activated Kinase 1 (TAK1), accompanied by suppression of NF-κB signaling. In contrast, fibronectin (FN1) preserved TAK1 stability and activation. Consistently, TAK1 expression was markedly reduced in cerebral microvessels from hypertensive mice and post-mortem brains of individuals with cSVD. Mechanistically, we demonstrate that COL1 promotes SMYD3-dependent, proteasome-mediated degradation of TAK1. Genetic or pharmacological inhibition of SMYD3 prevented TAK1 loss, restored NF-κB signalling, improved endothelial junction integrity, and enhanced nitric oxide bioavailability under low shear conditions. Notably, SMYD3 expression was elevated in both experimental and human cSVD. Importantly, SMYD3 inhibition in vivo ameliorated cognitive deficits in hypertensive mice. Together, these findings identify ECM remodelling as a critical determinant of endothelial signaling dysfunction in cSVD and uncover a previously unrecognised SMYD3–TAK1 axis linking mechanical and inflammatory pathways. Targeting SMYD3 to preserve TAK1 signalling represents a promising therapeutic strategy to restore vascular integrity and prevent hypertension-associated cognitive decline.

Characterization Of The Ubiquitin Ligase PDZRN3 As A Novel Actor Of Wnt Pathways In Vascular Morphogenesis And Integrity: Parmi les récepteurs Frizzled, Frizzled 4 est le seul à avoir un phénotype vasculaire fort. Parcriblage, nous avons identifié l’ubiquitine ligase PDZRN3 en tant que nouveau partenaire de la protéineadaptatrice Dvl3 qui agit en aval de Fzd4. En utilisant des modèles murins inductibles, nous montronsque la délétion de PDZRN3 induit une létalité embryonnaire suite à des défauts de vascularisation dusac amniotique ; et que PDZRN3 est requis pour une vascularisation normale de la rétine. De par sonactivité d’ubiquitine ligase, PDZRN3 induit la prise en charge du complexe Fzd4/ Dvl3 par les vésiculesd’endocytose ce qui permet la transduction du signal après fixation du ligand Wnt5a sur le récepteurFzd4. PDZRN3 régule également le maintien des jonctions des cellules endothéliales et l’intégrité de labarrière hémato-encéphalique. La délétion de PDZRN3 stabilise les microvaisseaux après ischémiecérébrale. PDZRN3 induit la disruption des jonctions serrées et la rupture de la barrièrehématoencéphalique en ubiquitinant la protéine d’échafaudage MUPP1.

Activating mutations in KRAS occur in approximately 30% of lung adenocarcinomas. Despite advances in RAS-targeted therapies, intrinsic resistance limits their long-term efficacy. Here, we identify elevated levels of wild-type KRAS (WT-KRAS) protein as a key driver of intrinsic resistance in KRAS-mutant lung tumors. KRAS accumulation results from impaired LZTR1-mediated degradation, triggered either by LZTR1 loss or pharmacological RAS inhibition. Stabilized WT-KRAS activates the mTOR/HIF1α pathway by promoting lysosomal recruitment of the SLC3A2/SLC7A5 amino acid transporter complex, reprogramming lysosomal amino acid sensing. Shallow deletions of LZTR1, present in up to 40% of KRAS-mutant lung adenocarcinomas, are associated with increased mTOR activity and may contribute to therapeutic resistance to RAS inhibitors. Co-inhibition of mTOR or the SLC3A2/SLC7A5 complex using dactolisib or JPH203 restores sensitivity to KRAS inhibitors in vitro and in vivo. These findings support combinatorial targeting of mTOR signaling or amino acid transport to overcome intrinsic resistance in KRAS-mutant lung cancer.

The landscape of clinical trials aimed at targeting specific proteins has experienced significant advancements, presenting promising opportunities for the development of effective therapeutics across a range of diseases. These trials focus on the investigation of modulation of protein functions, utilizing innovative technologies such as PROTACs (Proteolysis-Targeting Chimeras) and other protein degraders. These innovative approaches aim to address previously undruggable targets, enhancing the specificity and efficacy of treatments. The current landscape of clinical trials encompasses a diverse array of therapeutic areas, including oncology, autoimmune diseases, and neurological disorders. For instance, drugs like ARV-471 and ARV-110 are in advanced phases for treating metastatic breast cancer and prostate cancer, respectively, by targeting estrogen and androgen receptors. Early-phase trials explored the potential of targeting proteins like IKZF1/3 in multiple myeloma and IRAK4 in autoimmune diseases. The conducted trials not only emphasize the therapeutic potential of protein degradation but also highlight the challenges associated with bioavailability, stability, and delivery mechanisms. As these clinical trials advance, they possess the potential to transform treatment paradigms, providing renewed hope for patients facing complex and refractory conditions.

Chemotherapy-induced cardiotoxicity is a critical issue in cardio-oncology, as cancer treatments often lead to severe cardiovascular complications. Approximately 10% of cancer patients succumb to cardiovascular problems, with lung cancer patients frequently experiencing arrhythmias, cardiac failure, tamponade, and cardiac metastasis. The cardiotoxic effects of anti-cancer treatments manifest at both cellular and tissue levels, causing deformation of cardiomyocytes, leading to contractility issues and fibrosis. Repeated irradiation and chemotherapy increase the risk of valvular, pericardial, or myocardial diseases. Multi-OMICs analyses reveal that targeting specific pathways as well as specific protein modifications, such as ubiquitination and phosphorylation, could offer potential therapeutic alternatives to current treatments, including Angiotensin converting enzymes (ACE) inhibitors and beta-blockers that mitigate symptoms but do not prevent cardiomyocyte death, highlighting the need for more effective therapies to manage cardiovascular defects in cancer survivors. This review explores the xenobiotic nature of chemotherapy agents and their impact on cardiovascular health, aiming to identify novel biomarkers and therapeutic targets to mitigate cardiotoxicity.

Recent technological advancements, including computer-assisted drug discovery, gene-editing techniques, and high-throughput screening approaches, have greatly expanded the palette of methods for the discovery of peptides available to researchers. These emerging strategies, driven by recent advances in bioinformatics and multi-omics, have significantly improved the efficiency of peptide drug discovery when compared with traditional in vitro and in vivo methods, cutting costs and improving their reliability. An added benefit of peptide-based drugs is the ability to precisely target protein–protein interactions, which are normally a particularly challenging aspect of drug discovery. Another recent breakthrough in this field is targeted protein degradation through proteolysis-targeting chimeras. These revolutionary compounds represent a noteworthy advancement over traditional small-molecule inhibitors due to their unique mechanism of action, which allows for the degradation of specific proteins with unprecedented specificity. The inclusion of a peptide as a protein-of-interest-targeting moiety allows for improved versatility and the possibility of targeting otherwise undruggable proteins. In this review, we discuss various novel wet-lab and computational multi-omic methods for peptide drug discovery, provide an overview of therapeutic agents discovered through these cutting-edge techniques, and discuss the potential for the therapeutic delivery of peptide-based drugs.

Despite the advances in modern cancer therapy, malignant diseases are still a leading cause of morbidity and mortality worldwide. Conventional treatment methods frequently lead to side effects and drug resistance in patients, highlighting the need for novel therapeutic approaches. Recent findings have identified the existence of non-canonical micropeptides, an additional layer of the proteome complexity, also called the microproteome. These small peptides are a promising class of therapeutic agents with the potential to address the limitations of current cancer treatments. The microproteome is encoded by regions of the genome historically annotated as non-coding, and its existence has been revealed thanks to recent advances in proteomic and bioinformatic technology, which dramatically improved the understanding of proteome complexity. Micropeptides have been shown to be biologically active in several cancer types, indicating their therapeutic role. Furthermore, they are characterized by low toxicity and high target specificity, demonstrating their potential for the development of better tolerated drugs. In this review, we survey the current landscape of known micropeptides with a role in cancer progression or treatment, discuss their potential as anticancer agents, and describe the methodological challenges facing the proteome field of research.

The RAS pathway is among the most frequently activated signaling nodes in cancer. However, the mechanisms that alter RAS activity in human pathologies are not entirely understood. The most prevalent post-translational modification within the GTPase core domain of NRAS and KRAS is ubiquitination at lysine 128 (K128), which is significantly decreased in cancer samples compared to normal tissue. Here, we found that K128 ubiquitination creates an additional binding interface for RAS GTPase-activating proteins (GAPs), NF1 and RASA1, thus increasing RAS binding to GAP proteins and promoting GAP-mediated GTP hydrolysis. Stimulation of cultured cancer cells with growth factors or cytokines transiently induces K128 ubiquitination and restricts the extent of wild-type RAS activation in a GAP-dependent manner. In KRAS mutant cells, K128 ubiquitination limits tumor growth by restricting RAL/ TBK1 signaling and negatively regulating the autocrine circuit induced by mutant KRAS. Reduction of K128 ubiquitination activates both wild-type and mutant RAS signaling and elicits a senescence-associated secretory phenotype, promoting RAS-driven pancreatic tumorigenesis.

Almost 30% of lung adenocarcinomas are driven by activating KRAS mutations. The heterogeneous clinical behavior observed in these cancers could be due to the imbalance of wild-type and oncogenic KRAS alleles. However, the role of RAS dysregulation at the protein level needs to be further explored. A genome-wide global protein stability screen identified the CUL3 ubiquitin ligase adaptor LZTR1, as a major proteostatic regulator of wild-type but not mutant KRAS. In KRAS -mutant lung adenocarcinoma, shallow deletion of LZTR1 is observed in up to 50% of patients and is associated with hypoxic signatures and poorer progression-free disease survival. In a Kras -mutant lung cancer mouse model, heterozygous loss of Lztr1 promoted tumor growth, led to peritumoral vascular remodeling, and limited the response to the KRAS-G12D inhibitor MRTX1133. The vascular alteration in LZTR1 -depleted lung cancer was mediated by increased wild-type KRAS protein dosage, which promoted mTOR pathway activation and a subsequent increase in VEGFA secretion. The inhibition of the PI3K/mTOR pathway using dactolisib normalized tumor vasculature, improved drug delivery, and overcame resistance to KRAS-G12D inhibitors. In summary, the dysregulation of RAS proteostasis contributes to lung tumorigenesis, and targeting wild-type KRAS signaling is crucial to overcome intrinsic resistance to inhibitors of mutant KRAS. Significance: Our study highlights the impact of RAS proteostasis on lung cancer development and progression. Vascular normalization achieved by suppressing wild-type KRAS signaling improved the delivery and response to MRTX1133 in KRAS -mutant lung cancer with shallow LZTR1 deletion.

Chemical agents can cause cancer in animals by damaging their DNA, mutating their genes, and modifying their epigenetic signatures. Carcinogen-induced preclinical cancer models are useful for understanding carcinogen-induced human cancers, as they can reproduce the diversity and complexity of tumor types, as well as the interactions with the host environment. However, these models also have some drawbacks that limit their applicability and validity. For instance, some chemicals may be more effective or toxic in animals than in humans, and the tumors may differ in their genetics and phenotypes. Some chemicals may also affect normal cells and tissues, such as by causing oxidative stress, inflammation, and cell death, which may alter the tumor behavior and response to therapy. Furthermore, some chemicals may have variable effects depending on the exposure conditions, such as dose, route, and duration, as well as the animal characteristics, such as genetics and hormones. Therefore, these models should be carefully chosen, validated, and standardized, and the results should be cautiously interpreted and compared with other models. This review covers the main features of chemically induced cancer models, such as genetic and epigenetic changes, tumor environment, angiogenesis, invasion and metastasis, and immune response. We also address the pros and cons of these models and the current and future challenges for their improvement. This review offers a comprehensive overview of the state of the art of carcinogen-induced cancer models and provides new perspectives for cancer research.