Histone demethylase KDM6B inhibitor GSK-J4 sensitizes glioma cells to tyrosine kinase inhibitor anlotinib in vitro by reducing PDGFRA expression

Synergistic antiproliferative effects of KIT tyrosine kinase inhibitors on neoplastic canine mast cells

Medullary thyroid carcinoma (MTC) is a neuroendocrine malignancy, caused by activating mutations of the RET proto-oncogene, with frequent lymph node and distant metastasis at diagnosis. Tyrosine kinase inhibitors (TKIs) that target the RET have proven effective for treatment of MTC, but resistance to TKIs evolves in half of the treated patients. We have previously shown that the expression levels of Activating Transcription Factor 4 (ATF4) which is a stress-induced transcription factor, significantly decreased or lost in half of the MTC tumors. We also demonstrated that forced expression of ATF4 or TKIs-induced level of ATF4 decreases survival of MTC cells by promoting degradation of RET, blocking the activation of RET downstream signaling pathways and subsequently induces apoptosis. More importantly, ATF4 knockdown by shRNA decreased the sensitivity to tyrosine kinase inhibitor-induced apoptosis. Further thyroid gland of Atf4-knockout mice showed C-cell hyperplasia, a precancerous lesion for MTC suggesting a potential tumor suppressor role of ATF4 in MTC. Stress-induced by the accumulation of unfolded proteins in the endoplasmic reticulum (ER) is a feature of specialized secretory cells, including MTC cells that secrete calcitonin. ATF4 promotes the induction of apoptosis under persistent stress conditions, although the mechanism is not clearly understood. We hypothesize that the combination of ATF4 inducer and TKIs causes an excessive cellular oxidative stress resulting in an activation of apoptosis, all of which may prevent resistance to TKIs. Here, we show that the ER-associated protein degradation (ERAD) inhibitor, eeyarestatin sensitizes MTC cells to the TKIs including sunitinib and vandetanib. The combination of eeyarestatin and TKIs causes a synergistic induction of ATF4 expression and its target genes, an accumulation of reactive oxygen species and subsequent cell death. Chromatin immunoprecipitation followed by sequencing assay (ChIP-seq) in MTC cells treated with eeyarestatin and immunoprecipitated with ATF4 and acetylated lysine 9 of histone 3, identified transcription Kruppel-like factor 9 (KLF9) gene as a transcriptional target of ATF4 activation. KLF9 plays a functional role in oxidative stress-induced cell death. Treatment with eeyarestatin and vandetanib alone or in combination increases the occupancy of ATF4 at the promoter of KLF9 gene and stimulates the expression of KLF9. Depletion of ATF4 by shRNA leads to downregulation of KLF9 expression and prevents oxidative stress-induced cell death. These findings suggest that induction of the ATF4/KLF9 axis causes oxidative stress leading to excessive ER stress, and subsequent cell death. Thus, combining TKIs and ERAD inhibitors that promote ATF4 levels could be effective therapeutic strategies for treating MTC and preventing resistance to TKIs. Citation Format: Rozita Bagheri-Yarmand, Krishna M. Sinha, Ling Li, Yue Lu, Robert F. Gagel. Tyrosine kinase and ERAD inhibitors promote oxidative stress-induced apoptosis through activation of ATF4 / KLF9 axis in medullary thyroid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2426.

Effect of Imatinib on Proliferation, Apoptosis and Expression of Platelet Derived Growth Factor Receptor By Mesenchymal Stem Cells

Recent evidence suggests that secretory vesicle formation from the TGN is regulated by cytosolic signaling pathways involving small GTP- binding proteins, heterotrimeric G proteins, inositol phospholipid metabolism, and protein serine/threonine phosphorylation. At the cell surface, protein phosphorylation and dephosphorylation on tyrosine residues can rapidly modulate cytosolic signaling pathways in response to extracellular stimuli and have been implicated in the internalization and sorting of signaling receptors. to determine if phosphotyrosine metabolism might also regulate secretory vesicle budding from the TGN, we treated permeabilized rat pituitary GH3 cells with inhibitors of either tyrosine phosphatases or tyrosine kinases. We demonstrate that the tyrosine phosphatase inhibitors pervanadate and zinc potently inhibited budding of nascent secretory vesicles. Tyrphostin A25 (TA25) and other tyrosine kinase inhibitors also prevented secretory vesicle release, suggesting that vesicle formation requires both phosphatase and kinase activities. A stimulatory peptide derived from the NH2 terminus of the small GTP-binding protein ADP ribosylation factor 1 (ARF1) antagonized the inhibitory effect of TA25, indicating that both agents influence the same pathway leading to secretory vesicle formation. Antiphosphotyrosine immunoblotting revealed that protein tyrosine phosphorylation was enhanced after treatment with tyrosine phosphatase or kinase inhibitors. Subcellular fractionation identified several tyrosine phosphorylated polypeptides of approximately 175, approximately 130, and 90-110 kD that were enriched in TGN-containing Golgi fractions and tightly membrane associated. The phosphorylation of these polypeptides correlated with inhibition of vesicle budding. Our results suggest that in endocrine cells, protein tyrosine phosphrylation and dephosphorylation are required for secretory vesicle release from the TGN.

The histone H3 Lys 27 demethylase KDM6B promotes migration and invasion of glioma cells partly by regulating the expression of SNAI1

Targeted synthetic disease-modifying antirheumatic drugs in spondyloarthritis.

Introduction: In the last few years, several tyrosine kinase inhibitors (TKIs) have been synthesized and become available for preclinical studies and clinical trials. This article summarizes recent achievements in the mechanism of action, pharmacological properties, and clinical activity and toxicity, as well as the emerging role of TKIs in lymphoid malignancies, allergic diseases, and autoimmune disorders.Areas covered: A literature review was conducted of the MEDLINE database PubMed for articles in English. Publications from 2000 through January 2012 were scrutinized. The search terms used were Bruton's tyrosine kinase (Btk) inhibitors, PCI-32765, GDC-0834, LFM-A13, AVL-101, AVL-292, spleen tyrosine kinase (Syk) inhibitors, R343, R406, R112, R788, fostamatinib, BAY-61-3606, C-61, piceatannol, Lyn, imatinib, nilotinib, bafetinib, dasatinib, GDC-0834, PP2, SU6656 in conjunction with lymphoid malignancy, NHL, CLL, autoimmune disease, allergic disease, asthma, and rheumatoid arthritis. Conference proceedings from the previous 5 years of the American Society of Hematology, European Hematology Association, American Society of Clinical Oncology, and ACR/ARHP Annual Scientific Meetings were searched manually. Additional relevant publications were obtained by reviewing the references from the chosen articles.Expert opinion: The use of TKIs, especially inhibitors of Btk, Syk, and Lyn, is a promising new strategy for targeted treatment of B-cell lymphoid malignancies, autoimmune disorders and allergic diseases. However, definitive data from ongoing and future clinical trials will aid in better defining the status of TKIs in the treatment of these disorders.

Introduction: Cholangiocarcinomas (CCA) are aggressive tumors with poor prognosis. A large number of CCA patients are already in late stage at diagnosis so are only amenable to systematic therapies. Traditional systematic therapies are often associated with high toxicity and low efficacy. Several advanced therapies, including immune checkpoint inhibitors (ICI) and tyrosine kinase inhibitors (TKI) are under testing against CCA. These efforts are highlighted by the recent FDA approval of pemigatinib, which blocks FGFR2 activation. Combination use of anti-angiogenesis agents with ICI or TKI are also hot research areas. However, data are lacking to demonstrate the real-world value of the above advanced or testing therapies. Here we aim to use a real-world CCA patient set to explore the clinic value and best strategy of combination therapy in CCA. Methods: We retrospectively enrolled 286 CCA patients with a majority (219) of intrahepatic CCA. In total, 73 patients received anti-PD-1/L1 therapies, including mono-use of pembrolizumab (19), camelizumab (12), nivolumab (11), toripalimab (7), and sintilimab (4), and mixed-use (8) or unspecified (12) of the above anti-PD-1/L1 agents. On the other hand, 68 patients received one or more treatment of anlotinib, apatinib, regorafenib, and sorafenib/sorafenib tosylate TKIs. We performed whole-exome sequencing (WES) (all 286 patients) and RNA-seq (200 patients) to analyze the patients' somatic mutation profiles and tumor microenvironment (TME). We also analyzed their survival benefits stratified by TME, treatment, and gene mutation/fusion status. Results: We identified 59 patients with FGFR family gene copy number (CNV) gain or gene fusion (9 in FGFR2). Treatment with the above five mentioned TKIs show good prognosis (2-year survival rate 100% vs. 60% in un-treated, p=0.057). However, lenvatinib, an anti-VEGF angiogenesis inhibitor, showed no survival benefit in the 59 patients (HR 0.879, p=0.837). This conclusion was largely recapitulated in 114 patients who had higher transcription (top quartile) of FGFR family genes. Treatment with the first 5 TKIs (counted together) gave HR 0.395 (treated vs. non-treated, p=0.041), while lenvatinib gave HR 0.586 (p=0.164). For the 184 patients with survival data, the above mentioned anti-PD-1/L1 treatments gave HR 0.667 (treated vs. un-treated, p=0.073). Among these who received anti-PD-1/L1 treatment, 64 also received lenvatinib treatment and they gave HR 0.647 (treated vs. non-treated, p=0.265). Conclusion: Multi-TKIs and ICIs treatment are effective in prolonging patient lives in CCA. The combination use of lenvatinib with other TKIs has limited survival benefit. However, it has a trend of giving some additional benefit when in combination with anti-PD-1/L1 therapies. However, more testings are needed to confirm this. Citation Format: Jun Liu, Junning Cao, Guan Wang, Bingyang Hu, Chun Dai, Shengzhou Wang, Fei Xu, Qiang Xu, Shichun Lu. Analysis of efficacy of receptor tyrosine kinase and immune checkpoint inhibitors and insights to potential combinatorial treatment strategies in cholangiocarcinomas [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 944.

ABSTRACT. Recently, Zanubrutinib, as a novel, selective covalent and potent inhibitor Bruton’s tyrosine kinase (BTK), has been used to treat COVID-19 patients. In this regard, the interaction of Zanubrutinib with Bruton’s tyrosine kinase (BTK) inhibitor studied. The docking molecular and ONIOM2 (B3LYP/6-311G: UFF) methods were conducted to investigate the binding properties of Zanubrutinib with Bruton’s tyrosine kinase (BTK) inhibitor. The active sites of the Bruton’s tyrosine kinase (BTK) inhibitor is evaluated by docking molecular and is used for ONIOM2 calculations. The binding between Zanubrutinib and the BTK receptor is strong because values of the free binding energy are negative. The hydrogen bonds are formed between Zanubrutinib and three residues of the active amino acids Asn484, Arg 525, and Asn 526 at 2.69, 3.15, and 2.75 Å, respectively, which create through the O-atom, and the N-atom of Zanubrutinib. ONIOM2 calculation was displayed that the stability system in the solvent phase is higher than the gas-phase, which can occur due to the solvation of the species. Our results display the first mechanistic study of BTK inactivation by Zanubrutinib. This study can be helpful in the design of covalent drugs that target BTK and other similar targets.
 
 
 KEY WORDS: Bruton’s tyrosine kinase inhibitor, Docking molecular, Zanubrutinib, Two-layer integrated orbital molecular mechanics
 
 Bull. Chem. Soc. Ethiop. 2022, 36(2), 479-485. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i2.19

Axl Receptor Axis: A New Therapeutic Target in Lung Cancer

The Challenges of Third-Generation EGFR Tyrosine Kinase Inhibitors in the Therapy of Advanced NSCLC

Nuclear factor kappa B (NF-kappa B), consisting of p50 and p65, is bound to a cytoplasmic retention protein, I kappa B, in a resting state, and the stimulation of cells with a variety of inflammatory stimuli induces the dissociation of NF-kappa B from I kappa B and the nuclear translocation of NF-kappa B, thereby activating several genes involved in inflammatory responses, such as interleukin (IL)-6, IL-8, and tumor necrosis factor alpha. In order to elucidate the precise mechanism of NF-kappa B activation, we have established lipopolysaccharide (LPS)-dependent NF-kappa B activation in a cell-free system using plasma membrane-enriched, cytosol, and nuclear fractions extracted from a human monocytic cell line, THP-1, by disruption with sonication followed by a differential centrifugation. The combination of plasma membrane-enriched fraction and cytosol was sufficient to activate NF-kappa B in a LPS/CD14-dependent manner only in the presence of ATP as judged by the binding of NF-kappa B to the IL-8 gene kappa B site on an electrophoretic mobility shift assay. LPS-dependent NF-kappa B activation was inhibited by protein kinase inhibitors, such as staurosporine, herbimycin A, tyrphostin, and genistein, but not mitogen-activated protein kinase substrate, cGMP-dependent protein kinase, cAMP-dependent protein kinase, protein kinase C, and calmodulin-dependent protein kinase II inhibitory peptides, suggesting that staurosporine-sensitive kinase(s) as well as tyrosine kinase(s) are involved in LPS-mediated NF-kappa B activation. In addition, LPS induced the phosphorylation of I kappa B-alpha, starting at 5 min after the stimulation in a cell-free system. Moreover, the phosphorylation was inhibited by herbimycin A and tyrphostin, but not staurosporine, suggesting that these protein kinase inhibitors act at distinct steps of signal transmission. Establishment of ligand-dependent activation of NF-kappa B in a cell-free system will facilitate identification of protein kinase(s) and its substrate(s) involved in LPS-mediated NF-kappa B activation.

Inhibitors of tyrosine kinases may be effective in the treatment of certain cancers and chronic inflammatory conditions for which current therapy is either inadequate or lacking. As such, tyrosine kinase inhibitors are attractive targets for pharmaceutical research and may emerge as an important new class of therapeutic agents. Significant progress has been made during recent years towards the development of potent and highly selective tyrosine kinase inhibitors. In particular, recent discovery efforts at Zeneca have lead to the identification of very potent and selective inhibitors of EGF receptor tyrosine kinase. Likewise, a class of potent and selective inhibitors of PDGF receptor tyrosine kinase were described by Rhone-Poulenc Rorer and more recently by Ciba-Geigy. New inhibitors of p56lck and pp60src were also reported. This review focuses mainly on developments which appeared in the patent literature from 1993 to mid-1995. References to the primary literature are limited to studies which are relevan...

Persistent infection by high-risk human papillomaviruses (HPVs) is associated with the development of cervical cancer and a subset of anogenital and head and neck squamous cell carcinomas. Abnormal expression of cellular microRNAs (miRNAs) plays an important role in the development of cancer, including HPV-related tumors. In this study, we demonstrated that miR-146a-5p was down-regulated by E6 and, less efficiently, by E7 of high-risk HPV16 in keratinocytes and the presence of low levels of this miRNA in cervical carcinoma cell lines and in high-risk HPV-positive cervical specimens. Down-regulation of miR-146a-5p was mediated at least in part by the transcription repressor c-MYC, through binding sites in the miR-146a promoter. Overexpression of miR-146a-5p significantly inhibited proliferation and migration of keratinocytes and cervical cancer cells. The histone demethylase KDM2B was validated as a new direct target of miR-146a-5p and two putative binding sites for miR-146a-5p were identified in its 3'UTR sequence. Western blot analysis and immunohistochemistry showed that KDM2B was overexpressed in HPV16 E6/E7-positive keratinocytes, in cervical cancer cell lines, and in a subset of invasive cervical carcinomas and HPV-positive laryngeal squamous cell carcinomas. In these tumors, KDM2B overexpression was associated with c-MYC copy number gain. In vitro, silencing of KDM2B inhibited proliferation of cervical cancer cells. In conclusion, this study identified a novel player, the hystone demethylase KDM2B, in HPV-mediated tumorigenesis. E6 and, less efficiently, E7 of high-risk HPV16 up-regulated KDM2B expression in human keratinocytes through a pathway involving overexpression of c-MYC, which in turn downregulated miR-146a-5p.

Inhibition of basophil histamine release by tyrosine kinase and phosphatidylinositol 3-kinase inhibitors