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Janus Kinase-Signal Transducer and Activator of Transcription Inhibitors for the Treatment and Management of Cancer

Rizwi FA, Abubakar M, Puppala ER, Goyal A, Bhadrawamy CV, Naidu VGM, et al.

J Environ Pathol Toxicol Oncol, 2023;42(4):15-29.
PMID: 37522565 DOI: 10.1615/JEnvironPatholToxicolOncol.2023045403

According to the World Health Organization (WHO), cancer is the second-highest cause of mortality worldwide, killing nearly 9.6 million people annually. Despite the advances in diagnosis and treatment during the last couple of decades, it remains a serious concern due to the limitations of currently available cancer management strategies. Therefore, alternative strategies are highly required to overcome these glitches. In addition, many etiological factors such as environmental and genetic factors initiate the activation of the Janus kinase (JAK)-signal transducer and activator of the transcription (STAT) pathway. This aberrant activation of the JAK-STAT pathway has been reported in various disease states, including inflammatory conditions, hematologic malignancies, and cancer. For instance, many patients with myeloproliferative neoplasms carry the acquired gain-of-function JAK2 V617F somatic mutation. This knowledge has dramatically improved our understanding of pathogenesis and has facilitated the development of therapeutics capable of suppressing the constitutive activation of the JAK-STAT pathway. Our aim is not to be expansive but to highlight emerging ideas towards preventive therapy in a modern view of JAK-STAT inhibitors. A series of agents with different specificities against different members of the JAK family of proteins is currently undergoing evaluation in clinical trials. Here we give a summary of how JAK-STAT inhibitors function and a detailed review of current clinical drugs for managing cancer as a new therapeutic approach.

Matched MeSH terms: STAT Transcription Factors/metabolism
Discovery of plant-based phytochemical as effective antivirals that target the non-structural protein C of the Nipah virus through computational methods

Sureshan M, Prabhu D, Joshua SN, Sasikumar SV, Rajamanikandan S, Govindhapriya M, et al.

J Biomol Struct Dyn, 2024 Apr;42(7):3568-3578.
PMID: 37222609 DOI: 10.1080/07391102.2023.2214236

Nipah Virus (NiV) belongs to the Paramyxoviridae family and was first identified during an outbreak in Malaysia. Some initial symptoms include mild fever, headache and sore throat, which could escalate to respiratory illness and brain inflammation. The mortality rate of NiV infection can range from 40% to 75%, which is quite high. This is mainly due to the lack of efficient drugs and vaccines. In most instances, NiV is transmitted from animals to humans. Non-Structural Proteins (C, V and W) of the Nipah virus impede the host immune response by obstructive the JAK/STAT pathway. However, Non-Structural Proteins - C (NSP-C) plays a vital role in NiV pathogenesis, which includes IFN antagonist activity and viral RNA production. In the present study, the full-length structure of NiV-NSP-C was predicted using computational modelling, and the stability of the structure was analysed using 200 ns molecular dynamic (MD) simulation. Further, the structure-based virtual screening identified five potent phytochemicals (PubChem CID: 9896047, 5885, 117678, 14887603 and 5461026) with better binding affinity against NiV-NSP-C. DFT studies clearly showed that the phytochemicals had higher chemical reactivity, and the complex MD simulation depicted that the identified inhibitors exhibited stable binding with NiV-NSP-C. Furthermore, experimental validation of these identified phytochemicals would likely control the infection of NiV.Communicated by Ramaswamy H. Sarma.

Matched MeSH terms: STAT Transcription Factors/metabolism
Fulltext Phosphorylation of interferon regulatory factor 9 (IRF9)

Paul A, Ismail MN, Tang TH, Ng SK

Mol Biol Rep, 2023 Apr;50(4):3909-3917.
PMID: 36662450 DOI: 10.1007/s11033-023-08253-3

BACKGROUND: IRF9 is a transcription factor that mediates the expression of interferon-stimulated genes (ISGs) through the Janus kinase-Signal transducer and activator of transcription (JAK-STAT) pathway. The JAK-STAT pathway is regulated through phosphorylation reactions, in which all components of the pathway are known to be phosphorylated except IRF9. The enigma surrounding IRF9 regulation by a phosphorylation event is intriguing. As IRF9 plays a major role in establishing an antiviral state in host cells, the topic of IRF9 regulation warrants deeper investigation.
METHODS: Initially, total lysates of 2fTGH and U2A cells (transfected with recombinant IRF9) were filter-selected and concentrated using phosphoprotein enrichment assay. The phosphoprotein state of IRF9 was further confirmed using Phos-tag™ assay. All protein expression was determined using Western blotting. Tandem mass spectrometry was conducted on immunoprecipitated IRF9 to identify the phosphorylated amino acids. Finally, site-directed mutagenesis was performed and the effects of mutated IRF9 on relevant ISGs (i.e., USP18 and Mx1) was evaluated using qPCR.
RESULTS: IRF9 is phosphorylated at S252 and S253 under IFNβ-induced condition and R242 under non-induced condition. Site-directed mutagenesis of S252 and S253 to either alanine or aspartic acid has a modest effect on the upregulation of USP18 gene-a negative regulator of type I interferon (IFN) response-but not Mx1 gene.
CONCLUSION: Our preliminary study shows that IRF9 is phosphorylated and possibly regulates USP18 gene expression. However, further in vivo studies are needed to determine the significance of IRF9 phosphorylation.

Matched MeSH terms: STAT Transcription Factors/metabolism
Gene and protein expression profiles of JAK-STAT signalling pathway in the developing brain of the Ts1Cje down syndrome mouse model

Lee HC, Md Yusof HH, Leong MP, Zainal Abidin S, Seth EA, Hewitt CA, et al.

Int J Neurosci, 2019 Sep;129(9):871-881.
PMID: 30775947 DOI: 10.1080/00207454.2019.1580280

Aims: The JAK-STAT signalling pathway is one of the key regulators of pro-gliogenesis process during brain development. Down syndrome (DS) individuals, as well as DS mouse models, exhibit an increased number of astrocytes, suggesting an imbalance of neurogenic-to-gliogenic shift attributed to dysregulated JAK-STAT signalling pathway. The gene and protein expression profiles of JAK-STAT pathway members have not been characterised in the DS models. Therefore, we aimed to profile the expression of Jak1, Jak2, Stat1, Stat3 and Stat6 at different stages of brain development in the Ts1Cje mouse model of DS. Methods: Whole brain samples from Ts1Cje and wild-type mice at embryonic day (E)10.5, E15, postnatal day (P)1.5; and embryonic cortex-derived neurospheres were collected for gene and protein expression analysis. Gene expression profiles of three brain regions (cerebral cortex, cerebellum and hippocampus) from Ts1Cje and wild-type mice across four time-points (P1.5, P15, P30 and P84) were also analysed. Results: In the developing mouse brain, none of the Jak/Stat genes were differentially expressed in the Ts1Cje model compared to wild-type mice. However, Western blot analyses indicated that phosphorylated (p)-Jak2, p-Stat3 and p-Stat6 were downregulated in the Ts1Cje model. During the postnatal brain development, Jak/Stat genes showed complex expression patterns, as most of the members were downregulated at different selected time-points. Notably, embryonic cortex-derived neurospheres from Ts1Cje mouse brain expressed lower Stat3 and Stat6 protein compared to the wild-type group. Conclusion: The comprehensive expression profiling of Jak/Stat candidates provides insights on the potential role of the JAK-STAT signalling pathway during abnormal development of the Ts1Cje mouse brains.

Matched MeSH terms: STAT Transcription Factors/metabolism
A century old renin-angiotensin system still grows with endless possibilities: AT1 receptor signaling cascades in cardiovascular physiopathology

Balakumar P, Jagadeesh G

Cell Signal, 2014 Oct;26(10):2147-60.
PMID: 25007996 DOI: 10.1016/j.cellsig.2014.06.011

Ang II, the primary effector pleiotropic hormone of the renin-angiotensin system (RAS) cascade, mediates physiological control of blood pressure and electrolyte balance through its action on vascular tone, aldosterone secretion, renal sodium absorption, water intake, sympathetic activity and vasopressin release. It affects the function of most of the organs far beyond blood pressure control including heart, blood vessels, kidney and brain, thus, causing both beneficial and deleterious effects. However, the protective axis of the RAS composed of ACE2, Ang (1-7), alamandine, and Mas and MargD receptors might oppose some harmful effects of Ang II and might promote beneficial cardiovascular effects. Newly identified RAS family peptides, Ang A and angioprotectin, further extend the complexities in understanding the cardiovascular physiopathology of RAS. Most of the diverse actions of Ang II are mediated by AT1 receptors, which couple to classical Gq/11 protein and activate multiple downstream signals, including PKC, ERK1/2, Raf, tyrosine kinases, receptor tyrosine kinases (EGFR, PDGF, insulin receptor), nuclear factor κB and reactive oxygen species (ROS). Receptor activation via G12/13 stimulates Rho-kinase, which causes vascular contraction and hypertrophy. The AT1 receptor activation also stimulates G protein-independent signaling pathways such as β-arrestin-mediated MAPK activation and Src-JAK/STAT. AT1 receptor-mediated activation of NADPH oxidase releases ROS, resulting in the activation of pro-inflammatory transcription factors and stimulation of small G proteins such as Ras, Rac and RhoA. The components of the RAS and the major Ang II-induced signaling cascades of AT1 receptors are reviewed.

Matched MeSH terms: STAT Transcription Factors/metabolism
Fulltext JAK-STAT and G-protein-coupled receptor signaling pathways are frequently altered in epitheliotropic intestinal T-cell lymphoma

Nairismägi ML, Tan J, Lim JQ, Nagarajan S, Ng CC, Rajasegaran V, et al.

Leukemia, 2016 06;30(6):1311-9.
PMID: 26854024 DOI: 10.1038/leu.2016.13

Epitheliotropic intestinal T-cell lymphoma (EITL, also known as type II enteropathy-associated T-cell lymphoma) is an aggressive intestinal disease with poor prognosis and its molecular alterations have not been comprehensively characterized. We aimed to identify actionable easy-to-screen alterations that would allow better diagnostics and/or treatment of this deadly disease. By performing whole-exome sequencing of four EITL tumor-normal pairs, followed by amplicon deep sequencing of 42 tumor samples, frequent alterations of the JAK-STAT and G-protein-coupled receptor (GPCR) signaling pathways were discovered in a large portion of samples. Specifically, STAT5B was mutated in a remarkable 63% of cases, JAK3 in 35% and GNAI2 in 24%, with the majority occurring at known activating hotspots in key functional domains. Moreover, STAT5B locus carried copy-neutral loss of heterozygosity resulting in the duplication of the mutant copy, suggesting the importance of mutant STAT5B dosage for the development of EITL. Dysregulation of the JAK-STAT and GPCR pathways was also supported by gene expression profiling and further verified in patient tumor samples. In vitro overexpression of GNAI2 mutants led to the upregulation of pERK1/2, a member of MEK-ERK pathway. Notably, inhibitors of both JAK-STAT and MEK-ERK pathways effectively reduced viability of patient-derived primary EITL cells, indicating potential therapeutic strategies for this neoplasm with no effective treatment currently available.

Matched MeSH terms: STAT Transcription Factors/metabolism*
Fulltext Clinical Aspects of Janus Kinase (JAK) Inhibitors in the Cardiovascular System in Patients with Rheumatoid Arthritis

Kotyla PJ, Islam MA, Engelmann M

Int J Mol Sci, 2020 Oct 07;21(19).
PMID: 33036382 DOI: 10.3390/ijms21197390

Janus kinase (JAK) inhibitors, a novel class of targeted synthetic disease-modifying antirheumatic drugs (DMARDs), have shown their safety and efficacy in rheumatoid arthritis (RA) and are being intensively tested in other autoimmune and inflammatory disorders. Targeting several cytokines with a single small compound leads to blocking the physiological response of hundreds of genes, thereby providing the background to stabilize the immune response. Unfortunately, blocking many cytokines with a single drug may also bring some negative consequences. In this review, we focused on the activity of JAK inhibitors in the cardiovascular system of patients with RA. Special emphasis was put on the modification of heart performance, progression of atherosclerosis, lipid profile disturbance, and risk of thromboembolic complications. We also discussed potential pathophysiological mechanisms that may be responsible for such JAK inhibitor-associated side effects.

Matched MeSH terms: STAT Transcription Factors/metabolism