JAK1/2 Inhibitors AZD1480 and CYT387 Inhibit Canine B-Cell Lymphoma Growth by Increasing Apoptosis and Disrupting Cell Proliferation

Regulation of programmed death ligand 1 expression by interferon-γ and tumour necrosis factor-α in canine tumour cell lines

Expression of programmed death ligand 1 (PD-L1) on tumour cells provides an immune evasion mechanism by inducing suppression of cytotoxic T cells. Various regulatory mechanisms of PD-L1 expression have been described in human tumours, however, little is known in canine tumours. To investigate whether inflammatory signalling is involved in PD-L1 regulation in canine tumours, the effects of interferon (IFN)-γ and tumour necrosis factor (TNF)-α treatment were examined in canine malignant melanoma cell lines (CMeC and LMeC) and an osteosarcoma cell line (HMPOS). The protein level of PD-L1 expression was upregulated by IFN-γ and TNF-α stimulation. Upon IFN-γ stimulation, all cell lines showed an increase in expression of PD-L1, signal transducer and activator of transcription (STAT)1, STAT3 and genes regulated by STAT activation. Upregulated expression of these genes was suppressed by the addition of a JAK inhibitor, oclacitinib. Contrastingly, upon TNF-α stimulation, all cell lines exhibited higher gene expression of the nuclear factor kappa B (NF-κB) gene RELA and genes regulated by NF-κB activation, whereas expression of PD-L1 was upregulated in LMeC only. Upregulated expression of these genes was suppressed by the addition of an NF-κB inhibitor, BAY 11-7082. The expression level of cell surface PD-L1 induced by IFN-γ and TNF-α treatment was reduced by oclacitinib and BAY 11-7082, respectively, indicating that upregulation of PD-L1 expression by IFN-γ and TNF-α stimulation is regulated via the JAK-STAT and NF-κB signalling pathways, respectively. These results provide insights into the role of inflammatory signalling in PD-L1 regulation in canine tumours.

STAT3 Inhibitors: A Novel Insight for Anticancer Therapy of Pancreatic Cancer

The signal transducer and activator of transcription (STAT) is a family of intracellular cytoplasmic transcription factors involved in many biological functions in mammalian signal transduction. Among them, STAT3 is involved in cell proliferation, differentiation, apoptosis, and inflammatory responses. Despite the advances in the treatment of pancreatic cancer in the past decade, the prognosis for patients with pancreatic cancer remains poor. STAT3 has been shown to play a pro-cancer role in a variety of cancers, and inhibitors of STAT3 are used in pre-clinical and clinical studies. We reviewed the relationship between STAT3 and pancreatic cancer and the latest results on the use of STAT3 inhibitors in pancreatic cancer, with the aim of providing insights and ideas around STAT3 inhibitors for a new generation of chemotherapeutic modalities for pancreatic cancer.

Ruxolitinib attenuates secondary injury after traumatic spinal cord injury

Excessive inflammation post-traumatic spinal cord injury (SCI) induces microglial activation, which leads to prolonged neurological dysfunction. However, the mechanism underlying microglial activation-induced neuroinflammation remains poorly understood. Ruxolitinib (RUX), a selective inhibitor of JAK1/2, was recently reported to inhibit inflammatory storms caused by SARS-CoV-2 in the lung. However, its role in disrupting inflammation post-SCI has not been confirmed. In this study, microglia were treated with RUX for 24 hours and then activated with interferon-γ for 6 hours. The results showed that interferon-γ-induced phosphorylation of JAK and STAT in microglia was inhibited, and the mRNA expression levels of pro-inflammatory cytokines tumor necrosis factor-α, interleukin-1β, interleukin-6, and cell proliferation marker Ki67 were reduced. In further in vivo experiments, a mouse model of spinal cord injury was treated intragastrically with RUX for 3 successive days, and the findings suggest that RUX can inhibit microglial proliferation by inhibiting the interferon-γ/JAK/STAT pathway. Moreover, microglia treated with RUX centripetally migrated toward injured foci, remaining limited and compacted within the glial scar, which resulted in axon preservation and less demyelination. Moreover, the protein expression levels of tumor necrosis factor-α, interleukin-1β, and interleukin-6 were reduced. The neuromotor function of SCI mice also recovered. These findings suggest that RUX can inhibit neuroinflammation through inhibiting the interferon-γ/JAK/STAT pathway, thereby reducing secondary injury after SCI and producing neuroprotective effects.

TYK2 is a prognostic biomarker and associated with immune infiltration in the lung adenocarcinoma microenvironment

BACKGROUND

Lung adenocarcinoma (LUAD) remains a major disease with high morbidity and mortality. The Janus kinases (JAKs) play a significant part in cellular biological process, inflammation and immunity. The role of JAK family in LUAD is still ambiguous.

METHODS

Various bioinformatics web portals were applied to explore the prognostic value of JAK family and their correlation with immune infiltration in LUAD.

RESULTS

JAK1/2 was downregulated, whereas JAK3/TYK2 was upregulated in patients with LUAD compared with the healthy controls in subgroup analyses based on gender, age, smoking habits, cancer stage, TP53 mutation status, and nodal metastasis status. Drug sensitivity indicated that low expression of JAK3 and TYK2 were resistant to most of the small molecules or drugs. High TYK2 expression was associated with favorable overall survival and relapse free survival in LUAD. Moreover, univariate and multivariate analysis revealed that clinical stage, lymphatic node metastasis and TYK2 expression were the independent factors affecting the prognosis of LUAD patients. TYK2 expression in LUAD patients was positively associated with the abundance of immune cells (B cells, CD8+ T cells, CD4+ T cells, neutrophils, and dendritic cells) and immune biomarker sets. Moreover, TYK2 was mainly involved in RNA binding, transcriptional mis-regulation in cancer and cell cycles. We also identified several TYK2-associated miRNA or transcription factor targets in LUAD.

CONCLUSION

Our results indicated that TYK2 was a biomarker and associated with prognosis and immune infiltration in LUAD, laying a foundation for further study about the role of TYK2 in the carcinogenesis and progression of LUAD.

Targeting TANK-binding kinase 1 (TBK1) in cancer

INTRODUCTION

TANK-binding kinase 1 (TBK1) is a Ser/Thr kinase with a central role in coordinating the cellular response to invading pathogens and regulating key inflammatory signaling cascades. While intact TBK1 signaling is required for successful anti-viral signaling, dysregulated TBK1 signaling has been linked to a variety of pathophysiologic conditions, including cancer. Several lines of evidence support a role for TBK1 in cancer pathogenesis, but the specific roles and regulation of TBK1 remain incompletely understood. A key challenge is the diversity of cellular processes that are regulated by TBK1, including inflammation, cell cycle, autophagy, energy homeostasis, and cell death. Nevertheless, evidence from pre-clinical cancer models suggests that targeting TBK1 may be an effective strategy for anti-cancer therapy in specific settings.

AREAS COVERED

This review provides an overview of the roles and regulation of TBK1 with a focus on cancer pathogenesis and drug targeting of TBK1 as an anti-cancer strategy. Relevant literature was derived from a PubMed search encompassing studies from 1999 to 2020.

EXPERT OPINION

TBK1 is emerging as a potential target for anti-cancer therapy. Inhibition of TBK1 alone may be insufficient to restrain the growth of most cancers; hence, combination strategies will likely be necessary. Improved understanding of tumor-intrinsic and tumor-extrinsic TBK1 signaling will inform novel therapeutic strategies.

Integrated analysis of transcriptome, methylome and copy number aberrations data of marginal zone lymphoma and follicular lymphoma in dog

Marginal zone lymphoma (MZL) and follicular lymphoma (FL) are classified as indolent B-cell lymphomas in dogs. Aside from the clinical and histopathological similarities with the human counterpart, the molecular pathogenesis remains unclear. We integrated transcriptome, genome-wide DNA methylation and copy number aberration analysis to provide insights on the pathogenesis of canine MZL (n = 5) and FL (n = 7), also comparing them with diffuse large B-cell lymphoma (DLBCL). Transcriptome profiling highlighted the presence of similar biological processes affecting both histotypes, including BCR and TLR signalling pathways. However, FLs showed an enrichment of E2F targets, whereas MZLs were characterized by MYC-driven transcriptional activation signatures. FLs showed a distinctive loss on chr1 containing CEACAM23 and 24, conversely MZLs presented multiple recurrent gains on chr13, where MYC is located. The distribution of methylation peaks was similar between the two histotypes. Integrating data from the three omics, FLs resulted clearly separated from MZLs and DLBCL dataset. MZLs showed the enrichment of FoxM1 network and TLR associated TICAM1-dependent IRFs activation pathway. However, no specific signatures differentiated MZLs from DLBCLs. In conclusion, our study presents the first comprehensive analysis of molecular and epigenetic pathogenesis of canine FL and MZL.

Signal Pathways and Therapeutic Prospects of Diffuse Large B Cell Lymphoma

BACKGROUND

Diffuse Large B Cell Lymphoma (DLBCL) is the most common type of non-Hodgkin lymphoma which is heterogeneous both clinically and morphologically. Over the past decades, significant advances have been made in the understanding of the molecular genesis, leading to the identification of multiple pathways and molecules that can be targeted for clinical benefit.

OBJECTIVE

The current review aims to present a brief overview of signal pathways of DLBCL, which mainly focus on B-cell antigen Receptor (BCR), Nuclear Factor-κB (NF-κB), Phosphatidylinositol-3-Kinase (PI3K) - protein kinase B (Akt) - mammalian Target of Rapamycin (mTOR), Janus Kinase (JAK) - Signal Transducer and Activator (STAT), Wnt/β-catenin, and P53 pathways.

METHODS

Activation of signal pathways may contribute to the generation, development, chemotherapy sensitivity of DLBCL, and expression of pathway molecules is associated with the prognosis of DLBCL. Some agents targeting these pathways have been proved effective and relevant clinical trials are in progress. These agents used single or combined with chemotherapy/each other might raise the possibility of improving clinical outcomes in DLBCL.

CONCLUSION

This review presents several signal pathways of DLBCL and targeted agents had a tendency to improve the curative effect, especially in high-risk or relapsed/refractory DLBCL.

JAK3 inhibitors based on thieno[3,2-d]pyrimidine scaffold: design, synthesis and bioactivity evaluation for the treatment of B-cell lymphoma

JAK3 is predominantly expressed in hematopoietic cells and has been a promising therapeutic target for the treatment of B-cell lymphoma. In this study, a new class of thieno[3,2-d]pyrimidines harboring acrylamide pharmacophore were synthesized as potent covalent JAK3 inhibitors (IC₅₀ < 10 nM). Among them, 9a and 9 g displayed the strongest inhibitory potency against JAK3 kinase activity, with IC₅₀ values of 1.9 nM and 1.8 nM, respectively. Furthermore, compared with the reference agents, Spebrutinib and Ibrutinib, 9a not only demonstrated enhanced antiproliferative activity against B lymphoma cells, but also showed very weak proliferative inhibition against normal peripheral blood mononuclear cells (PBMCs) at a concentration of 20 μM. Analysis of the mechanism revealed that 9a could induce the obvious apoptosis in B lymphoma cells and prevent JAK3-STAT3 cascade as well as BTK pathway. Taken together, 9a may be served as a potential new JAK3 inhibitor for the treatment of B-cell lymphoma.

Companion Animals as Models for Inhibition of STAT3 and STAT5

The use of transgenic mouse models has revolutionized the study of many human diseases. However, murine models are limited in their representation of spontaneously arising tumors and often lack key clinical signs and pathological changes. Thus, a closer representation of complex human diseases is of high therapeutic relevance. Given the high failure rate of drugs at the clinical trial phase (i.e., around 90%), there is a critical need for additional clinically relevant animal models. Companion animals like cats and dogs display chronic inflammatory or neoplastic diseases that closely resemble the human counterpart. Cat and dog patients can also be treated with clinically approved inhibitors or, if ethics and drug safety studies allow, pilot studies can be conducted using, e.g., inhibitors of the evolutionary conserved JAK-STAT pathway. The incidence by which different types of cancers occur in companion animals as well as mechanisms of disease are unique between humans and companion animals, where one can learn from each other. Taking advantage of this situation, existing inhibitors of known oncogenic STAT3/5 or JAK kinase signaling pathways can be studied in the context of rare human diseases, benefitting both, the development of drugs for human use and their application in veterinary medicine.

Identification of the JAK-STAT pathway in canine splenic hemangiosarcoma, thyroid carcinoma, mast cell tumor, and anal sac adenocarcinoma

Dysregulation of the Janus Kinase (JAK) - Signal Transducer and Activator of Transcription (STAT) cellular signaling pathway has been associated with the development and progression of multiple human cancers. STAT3 has been reported to be present and constitutively active in a number of veterinary cancers, and few studies have reported mutations or activation of JAK1 or JAK2. Archived tissue samples from 54 client-owned dogs with histologically-diagnosed HSA, MCT, TC, or AGASACA were evaluated by immunohistochemical scoring of JAK1, JAK2, STAT3, and the phosphorylated counterparts pJAK1, pJAK2, and pSTAT3. IHC scoring was retrospectively analyzed with retrospectively-collected clinical parameters, including patient characteristics, metastasis, and survival. JAK1, pJAK1, JAK2, pJAK2, STAT3, and pSTAT3 were present in all tumor types evaluated. Significant correlations between JAK 1/2 or STAT3 and activated or downstream components were identified in all tumor types. Clinically, pSTAT3 was correlated with development of metastasis in dogs with MCT, while increased JAK1 expression or activation may impact survival in dogs with MCT or HSA. These findings provide a foundation to further investigate the JAK-STAT pathway in canine malignancies for additional therapeutic options.

Ki-67/CD3 ratio in the diagnosis of chronic inflammatory enteropathy in dogs

BACKGROUND

T cells play a key role in the pathogenesis of chronic inflammatory enteropathy (CIE) in dogs. Cluster of differentiation 3 (CD3) antigen serves as a marker for T cells. In human medicine, Ki-67 is an indicator for cell growth but there are only a few studies in dogs with CIE.

OBJECTIVE

To investigate Ki-67 in relation to T cells as a marker for CIE in dogs.

ANIMALS

Eleven dogs with CIE and 6 healthy beagle controls (CO).

METHODS

Retrospective case-control study. Dogs were clinically assessed by the Canine Chronic Enteropathy Clinical Activity Index (CCECAI). Duodenal mucosal biopsy samples were endoscopically obtained for histopathologic examination by means of the World Small Animal Veterinary Association score. Double-labeled immunofluorescence was used to investigate colocalization of Ki-67 and CD3 in epithelium and lamina propria (LP) of villi and crypts.

RESULTS

Dogs with CIE had significantly higher clinical score (median, 5.0; interquartile range [IQR], 3-7) compared to CO (all 0; P < .001). The Ki-67/CD3 double-positive cells were significantly increased in the LP of the crypt region of CIE dogs (0.63 cells/mm² ; IQR, 0-0.54) versus CO (0.08 cells/mm² ; IQR, 0-0.26; P = .044). A significant correlation was found between CCECAI and the Ki-67/CD3 ratio in the LP of the crypt region (r = 0.670; P = .012) in dogs with CIE.

CONCLUSIONS AND CLINICAL IMPORTANCE

The Ki-67/CD3 ratio is upregulated in the LP crypt region of dogs with CIE and it correlates with clinical severity. Therefore, Ki-67/CD3 could be a useful tool for detection of CIE.

3-Deoxy-2β,16-dihydroxynagilactone E, a natural compound from Podocarpus nagi, preferentially inhibits JAK2/STAT3 signaling by allosterically interacting with the regulatory domain of JAK2 and induces apoptosis of cancer cells

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways, especially the JAK2/STAT3 pathway, play vital roles in the development of many malignancies. Overactivation of STAT3 promotes cancer cell survival and proliferation. Therefore, the JAK2/STAT3-signaling pathway has been considered a promising target for cancer therapy. In this study, we identified a natural compound 3-deoxy-2β,16-dihydroxynagilactone E (B6) from the traditional Chinese medicinal plant Podocarpus nagi as a potent inhibitor of STAT3 signaling. B6 preferentially inhibited the phosphorylation of STAT3 by interacting with and inactivating JAK2, the main upstream kinase of STAT3. B6 dose-dependently inhibited IL-6-induced STAT3 signaling with an IC₅₀ of 0.2 μM. In contrast to other JAK2 inhibitors, B6 did not interact with the catalytic domain but instead with the FERM-SH2 domain of JAK2. This interaction was JAK-specific since B6 had little effect on other tyrosine kinases. Furthermore, B6 potently inhibited the growth and induced apoptosis of MDA-MB-231 and MDA-MB-468 breast cancer cells with overactivated STAT3. Taken together, our study uncovers a novel compound and a novel mechanism for the regulation of JAK2 and offers a new therapeutic approach for the treatment of cancers with overactivated JAK2/STAT3.

Safety and toxicity of combined oclacitinib and carboplatin or doxorubicin in dogs with solid tumors: a pilot study

BACKGROUND

Oclacitinib is an orally bioavailable Janus Kinase (JAK) inhibitor approved for the treatment of canine atopic dermatitis. Aberrant JAK/ Signal Transducer and Activator of Transcription (STAT) signaling within hematologic and solid tumors has been implicated as a driver of tumor growth through effects on the local microenvironment, enhancing angiogenesis, immune suppression, among others. A combination of JAK/STAT inhibition with cytotoxic chemotherapy may therefore result in synergistic anti-cancer activity, however there is concern for enhanced toxicities. The purpose of this study was to evaluate the safety profile of oclacitinib given in combination with either carboplatin or doxorubicin in tumor-bearing dogs.

RESULT

Oclacitinib was administered at the label dose of 0.4-0.6 mg/kg PO q12h in combination with either carboplatin at 250-300 mg/m² or doxorubicin at 30 mg/m² IV q21d. Nine dogs were enrolled in this pilot study (n = 4 carboplatin; n = 5 doxorubicin). No unexpected toxicities occurred, and the incidence of adverse events with combination therapy was not increased beyond that expected in dogs treated with single agent chemotherapy. Serious adverse events included one Grade 4 thrombocytopenia and one Grade 4 neutropenia. No objective responses were noted.

CONCLUSIONS

Oclacitinib is well tolerated when given in combination with carboplatin or doxorubicin. Future work is needed to explore whether efficacy is enhanced in this setting.

Targeting NEDD8-activating enzyme is a new approach to treat canine diffuse large B-cell lymphoma

Canine diffuse large B-cell lymphoma (DLBCL), the most common hematologic malignancy of dogs, is associated with poor overall survival. The lack of conventional chemotherapies with sustainable efficacy warrants investigation of novel therapies. Pevonedistat (MLN4924) is a potent and selective small molecule NEDD8-activating enzyme inhibitor. In human activated B-cell-like (ABC) diffuse large B-cell lymphoma, pevonedistat induces lymphoma cell apoptosis, DNA damage and G1 cell cycle arrest by inhibiting the nuclear factor-κB (NF-κB) pathway. Genomic and transcriptomic studies showed that the NF-κB pathway is deregulated in canine DLBCL. Our results showed that pevonedistat treatment significantly reduces the viability of canine DLBCL cells by inducing G1 cell cycle arrest and apoptosis. Pevonedistat treatment inhibits NF-κB pathway activation and downregulates NF-κB target genes in canine DLBCL. Moreover, administration of pevonedistat to mice bearing canine DLBCL xenograft tumours resulted in tumour regression. Our in vivo and in vitro studies provide justification for future clinical application of pevonedistat as a potential new anti-cancer therapy that may benefit both canine and human species.