Identification of the SRC-family tyrosine kinase HCK as a therapeutic target in mantle cell lymphoma

Recent advances in hematopoietic cell kinase in cancer progression: Mechanisms and inhibitors

Hematopoietic cell kinase (Hck), a non-receptor tyrosine kinase belonging to the Src kinase family, is intricately linked to the pathogenesis of numerous human diseases, with a particularly pronounced association with cancer. Hck not only directly impacts the proliferation, migration, and apoptosis of cancer cells but also interacts with JAK/STAT, MEK/ERK, PI3K/AKT, CXCL12/CXCR4, and other pathways. Hck also influences the tumor microenvironment to facilitate the onset and progression of cancer. This paper delves into the functional role and regulatory mechanisms of Hck in various solid tumors. Additionally, it explores the implications of Hck in hematological malignancies. The review culminates with a summary of the current research status of Hck inhibitors, the majority of which are in the pre-clinical phase of investigation. Notably, these inhibitors are predominantly utilized in the therapeutic management of leukemia, with their combinatorial potential indicating promising avenues for future research. In conclusion, this review underscores the significance of the mechanism of Hck in solid tumors. This insight is crucial for comprehending the current research trends regarding Hck: targeted therapy against Hck shows great promise in both diagnosis and treatment of malignant tumors. Further investigation into the role of Hck in cancer, coupled with the development of specific inhibitors, has the potential to revolutionize approaches to cancer treatment.

The dual HCK/BTK inhibitor KIN-8194 impairs growth and integrin-mediated adhesion of BTKi-resistant mantle cell lymphoma

Although Bruton's tyrosine kinase (BTK) inhibitors (BTKi) have significantly improved patient prognosis, mantle cell lymphoma (MCL) is still considered incurable due to primary and acquired resistance. We have recently shown that aberrant expression of the Src-family tyrosine kinase hematopoietic cell kinase (HCK) in MCL correlates with poor prognosis, and that genetic HCK perturbation impairs growth and integrin-mediated adhesion of MCL cells. Here, we show that KIN-8194, a dual inhibitor of BTK and HCK with in vivo activity against Myd88-L265P-driven diffuse large B-cell lymphoma and Waldenström Macroglobulinemia, has a potent growth inhibitory effect in MCL cell lines and primary MCL cells, irrespective of their sensitivity to BTKi (ibrutinib and acalabrutinib). In BTKi-resistant cells this is mediated by inhibition of HCK, which results in repression of AKT-S6 signaling. In addition, KIN-8194 inhibits integrin-mediated adhesion of BTKi-sensitive and insensitive MCL cells to fibronectin and stromal cells in an HCK-dependent manner. Finally, we show that MCL cells with acquired BTKi resistance retain their sensitivity to KIN-8194. Taken together, our data demonstrate that KIN-8194 inhibits growth and integrin-mediated adhesion of BTKi-sensitive MCL cells, as well as MCL cells with primary or acquired BTKi resistance. This renders KIN-8194 a promising novel treatment for MCL patients.

HCK Promotes High-Grade Serous Ovarian Cancer Tumorigenesis through CD44 and NOTCH3 Signaling

High-grade serous ovarian cancer (HGSOC) is a highly aggressive and lethal subtype of ovarian cancer. While most patients initially respond to standard-of-care treatment, the majority will eventually relapse and succumb to their disease. Despite significant advances in our understanding of this disease, the mechanisms that govern the distinctions between HGSOC with good and poor prognosis remain unclear. In this study, we implemented a proteogenomic approach to analyze gene expression, proteomic and phosphoproteomic profiles of HGSOC tumor samples to identify molecular pathways that distinguish HGSOC tumors relative to clinical outcome. Our analyses identify significant upregulation of hematopoietic cell kinase (HCK) expression and signaling in poor prognostic HGSOC patient samples. Analyses of independent gene expression datasets and IHC of patient samples confirmed increased HCK signaling in tumors relative to normal fallopian or ovarian samples and demonstrated aberrant expression in tumor epithelial cells. Consistent with the association between HCK expression and tumor aggressiveness in patient samples, in vitro phenotypic studies showed that HCK can, in part, promote cell proliferation, colony formation, and invasive capacity of cell lines. Mechanistically, HCK mediates these phenotypes, partly through CD44 and NOTCH3-dependent signaling, and inhibiting CD44 or NOTCH3 activity, either genetically or through gamma-secretase inhibitors, can revert HCK-driven phenotypes.

IMPLICATIONS

Collectively, these studies establish that HCK acts as an oncogenic driver of HGSOC through aberrant activation of CD44 and NOTCH3 signaling and identifies this network as a potential therapeutic opportunity in a subset of patients with aggressive and recurrent HGSOC.

Insights on hematopoietic cell kinase: An oncogenic player in human cancer

Hematopoietic cell kinase (Hck) is a member of the Src family and is expressed in hematopoietic cells. By regulating multiple signaling pathways, HCK can interact with multiple receptors to regulate signaling events involved in cell adhesion, proliferation, migration, invasion, apoptosis, and angiogenesis. However, aberrant expression of Hck in various hematopoietic cells and solid tumors plays a crucial role in tumor-related properties, including cell proliferation and epithelial-mesenchymal transition. In addition, Hck signaling regulates the function of immune cells such as macrophages, contributing to an immunosuppressive tumor microenvironment. The clinical success of various kinase inhibitors targeting the Src kinase family has validated the efficacy of targeting Src, and therapies with highly selective Hck kinase inhibitors are in clinical trials. This article reviews Hck inhibition as an emerging cancer treatment strategy, focusing on the expressions and functions of Hck in tumors and its impact on the tumor microenvironment. It also explores preclinical and clinical pharmacological strategies for Hck targeting to shed light on Hck-targeted tumor therapy.

MALT1-dependent cleavage of CYLD promotes NF-κB signaling and growth of aggressive B-cell receptor-dependent lymphomas

The paracaspase mucosa-associated lymphoid tissue 1 (MALT1) is a protease and scaffold protein essential in propagating B-cell receptor (BCR) signaling to NF-κB. The deubiquitinating enzyme cylindromatosis (CYLD) is a recently discovered MALT1 target that can negatively regulate NF-κB activation. Here, we show that low expression of CYLD is associated with inferior prognosis of diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) patients, and that chronic BCR signaling propagates MALT1-mediated cleavage and, consequently, inactivation and rapid proteasomal degradation of CYLD. Ectopic overexpression of WT CYLD or a MALT1-cleavage resistant mutant of CYLD reduced phosphorylation of IκBα, repressed transcription of canonical NF-κB target genes and impaired growth of BCR-dependent lymphoma cell lines. Furthermore, silencing of CYLD expression rendered BCR-dependent lymphoma cell lines less sensitive to inhibition of NF-κΒ signaling and cell proliferation by BCR pathway inhibitors, e.g., the BTK inhibitor ibrutinib, indicating that these effects are partially mediated by CYLD. Taken together, our findings identify an important role for MALT1-mediated CYLD cleavage in BCR signaling, NF-κB activation and cell proliferation, which provides novel insights into the underlying molecular mechanisms and clinical potential of inhibitors of MALT1 and ubiquitination enzymes as promising therapeutics for DLBCL, MCL and potentially other B-cell malignancies.

Inhibition of casein kinase 2 sensitizes mantle cell lymphoma to venetoclax through MCL-1 downregulation

BCL-2 family proteins are frequently aberrantly expressed in mantle cell lymphoma (MCL). Recently, the BCL-2-specific inhibitor venetoclax has been approved by the US Food and Drug Administration for chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). In MCL, venetoclax has shown promising efficacy in early clinical trials; however, a significant subset of patients is resistant. By conducting a kinome-centered CRISPR-Cas9 knockout sensitizer screen, we identified casein kinase 2 (CK2) as a major regulator of venetoclax resistance in MCL. Interestingly, CK2 is over-expressed in MCL and high CK2 expression is associated with poor patient survival. Targeting of CK2, either by inducible short hairpin RNA (shRNA)-mediated knockdown of CK2 or by the CK2-inhibitor silmitasertib, did not affect cell viability by itself, but strongly synergized with venetoclax in both MCL cell lines and primary samples, also if combined with ibrutinib. Furthermore, targeting of CK2 reduced MCL-1 levels, which involved impaired MCL-1 translation by inhibition of eIF4F complex assembly, without affecting BCL-2 and BCL-XL expression. Combined, this results in enhanced BCL-2 dependence and, consequently, venetoclax sensitization. In cocultures, targeting of CK2 overcame stroma-mediated venetoclax resistance of MCL cells. Taken together, our findings indicate that targeting of CK2 sensitizes MCL cells to venetoclax through downregulation of MCL-1. These novel insights provide a strong rationale for combining venetoclax with CK2 inhibition as therapeutic strategy for MCL patients.

Tipping the balance: toward rational combination therapies to overcome venetoclax resistance in mantle cell lymphoma

Mantle cell lymphoma (MCL), an aggressive, but incurable B-cell lymphoma, is genetically characterized by the t(11;14) translocation, resulting in the overexpression of Cyclin D1. In addition, deregulation of the B-cell lymphoma-2 (BCL-2) family proteins BCL-2, B-cell lymphoma-extra large (BCL-X_L), and myeloid cell leukemia-1 (MCL-1) is highly common in MCL. This renders these BCL-2 family members attractive targets for therapy; indeed, the BCL-2 inhibitor venetoclax (ABT-199), which already received FDA approval for the treatment of chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML), shows promising results in early clinical trials for MCL. However, a significant subset of patients show primary resistance or will develop resistance upon prolonged treatment. Here, we describe the underlying mechanisms of venetoclax resistance in MCL, such as upregulation of BCL-X_L or MCL-1, and the recent (clinical) progress in the development of inhibitors for these BCL-2 family members, followed by the transcriptional and (post-)translational (dys)regulation of the BCL-2 family proteins, including the role of the lymphoid organ microenvironment. Based upon these insights, we discuss how rational combinations of venetoclax with other therapies can be exploited to prevent or overcome venetoclax resistance and improve MCL patient outcome.

A new role for the SRC family kinase HCK as a driver of SYK activation in MYD88 mutated lymphomas

HCK facilitates TLR/BCR crosstalk through activation of SYK in response to mutated MYD88.

The HCK inhibitor A419259 selectively blocks SYK activation in MYD88 mutated cell lines and primary WM lymphoplasmacytic cells.

The SRC family kinase (SFK) HCK is transcriptionally upregulated and activated by mutated MYD88 (MYD88^Mut), a key adaptor for Toll-receptor signaling. HCK activates BTK, AKT, and ERK in MYD88^Mut lymphomas. SYK, a B-cell receptor (BCR) component, is activated in MYD88^Mut lymphoma cells. Although the SFK LYN serves as a trigger for SYK activation in MYD88^Mut ABC DLBCL cells, LYN activity is muted in MYD88^Mut Waldenstrom macroglobulinemia (WM) cells. We therefore investigated a role for HCK in mediating SYK activation. Overexpression of wild-type (WT) (HCK^WT) or gatekeeper mutated (HCK^Thr333Met) HCK in MYD88^Mut lymphoma cells triggered SYK activation. Conversely, HCK knockdown reduced p-SYK in MYD88^Mut lymphoma cells. Coimmunoprecipitation experiments showed that HCK was complexed with p-SYK in MYD88^Mut BCWM.1 and TMD8 cells, but not in MYD88 WT Ramos cells. Rescue experiments in MYD88^Mut lymphoma cells expressing HCK^Thr333Met led to persistent HCK and SYK activation and resistance to the HCK inhibitor A419259. Treatment of primary MYD88^Mut WM cells with A419259 reduced p-HCK and p-SYK expression. Taken together, our findings show that SYK is activated by HCK in MYD88^Mut B-cell lymphomas cells, broaden the prosurvival signaling generated by aberrant HCK expression in response to MYD88^Mut, and help define HCK as an important therapeutic target in MYD88^Mut B-cell lymphomas.

HCK is a Potential Prognostic Biomarker that Correlates with Immune Cell Infiltration in Acute Myeloid Leukemia

Background. The tumor microenvironment (TME) plays a significant role in the progression and prognosis of acute myeloid leukemia (AML). This study is aimed at exploring TME-associated biomarkers and identify their potential mechanism in the microenvironment of AML. Method. In this study, the stromal, immune, and ESTIMATE scores of AML patients were evaluated with the ESTIMATE and CIBERSORT algorithms; then, the AML samples were divided into high- and low-score groups. We evaluated the association between clinicopathological characteristics, survival rate, and the stromal/immune/ESTIMATE scores. Furthermore, we identified TME-associated differentially expressed genes (DEGs) then carried out pathway enrichment analysis, protein-protein interaction (PPI) network, Cox regression analysis, and Kaplan-Meier survival analysis to select the most crucial genes. In addition, we further explored the potential mechanism of HCK in the AML microenvironment. Results. We identified 624 TME-associated DEGs and found that HCK was the most promising biomarker associated with AML. The results of the gene set enrichment analysis (GSEA) indicated that HCK was mainly involved in immune and inflammation-related signaling pathways. In addition, CIBERSORT analysis showed that HCK was closely related to tumor immune infiltration, with HCK expression associated with various infiltrating immune cells, including B cells, T cells, tumor-associated macrophages (TAM), NK cells, plasma cells, eosinophils, and neutrophils. Furthermore, HCK expression was closely related with ELN risk stratification in patients with AML. Conclusion. HCK could regulate immune cell infiltration in the microenvironment of AML and may act as a potential biomarker for the treatment and prognosis of AML patients.

Identification of key biomarkers in steroid-induced osteonecrosis of the femoral head and their correlation with immune infiltration by bioinformatics analysis

Objective

This study aimed to identify key diagnostic markers and immune infiltration of (SONFH) by bioinformatics analysis.

Methods

Related SONFH datasets were downloaded from the Gene Expression Omnibus (GEO) database. First, we identified the differentially expressed genes (DEGs) and performed the functional enrichment analysis. Then weighted correlation network analysis (WGCNA) and the MCODE plug-in in Cytoscape were used to identify the diagnostic markers of SONFH. Finally, CIBERSORT was used to analyze the immune infiltration between SONFH and healthy controls, and the correlation between infiltrating immune cells and diagnostic markers was analyzed.

Results

TYROBP, TLR2, P2RY13, TLR8, HCK, MNDA, and NCF2 may be key diagnostic markers of SONFH. Immune cell infiltration analysis revealed that Memory B cells and activated dendritic cells may be related to the SONFH process. Moreover, HCK was negatively correlated with CD8 T cells, and neutrophils were positively correlated with those key diagnostic markers.

Conclusions

TYROBP, TLR2, P2RY13, TLR8, HCK, MNDA, and NCF2 may be used as diagnostic markers of SONFH, and immune-related mechanism of SONFH and the potential immunotherapy are worthy of further study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-04994-7.

Identification of Transcriptional Pattern Related to Immune Cell Infiltration With Gene Co-Expression Network in Papillary Thyroid Cancer

BACKGROUND

A growing body of evidence suggests that immune cell infiltration in cancer is closely related to clinical outcomes. However, there is still a lack of research on papillary thyroid cancer (PTC).

METHODS

Based on single-sample gene set enrichment analysis (SSGSEA) algorithm and weighted gene co-expression network analysis (WGCNA) tool, the infiltration level of immune cell and key modules and genes associated with the level of immune cell infiltration were identified using PTC gene expression data from The Cancer Genome Atlas (TCGA) database. In addition, the co-expression network and protein-protein interactions network analysis were used to identify the hub genes. Moreover, the immunological and clinical characteristics of these hub genes were verified in TCGA and GSE35570 datasets and quantitative real-time polymerase chain reaction (PCR). Finally, receiver operating characteristic (ROC) curve analysis was used to evaluate the diagnostic value of hub genes.

RESULTS

Activated B cell, activated dendritic cell, CD56bright natural killer cell, CD56dim natural killer cell, Eosinophil, Gamma delta T cell, Immature dendritic cell, Macrophage, Mast cell, Monocyte, Natural killer cell, Neutrophil and Type 17 T helper cell were significantly changed between PTC and adjacent normal groups. WGCNA results showed that the black model had the highest correlation with the infiltration level of activated dendritic cells. We found 14 hub genes whose expression correlated to the infiltration level of activated dendritic cells in both TCGA and GSE35570 datasets. After validation in the TCGA dataset, the expression level of only 5 genes (C1QA, HCK, HLA-DRA, ITGB2 and TYROBP) in 14 hub genes were differentially expressed between PTC and adjacent normal groups. Meanwhile, the expression levels of these 5 hub genes were successfully validated in GSE35570 dataset. Quantitative real-time PCR results showed the expression of these 4 hub genes (except C1QA) was consistent with the results in TCGA and GSE35570 dataset. Finally, these 4 hub genes had diagnostic value to distinguish PTC and adjacent normal controls.

CONCLUSIONS

HCK, HLA-DRA, ITGB2 and TYROBP may be key diagnostic biomarkers and immunotherapy targets in PTC.

The HCK/BTK inhibitor KIN-8194 is active in MYD88-driven lymphomas and overcomes mutated BTKCys481 ibrutinib resistance

Activating mutations in MYD88 promote malignant cell growth and survival through hematopoietic cell kinase (HCK)-mediated activation of Bruton tyrosine kinase (BTK). Ibrutinib binds to BTKCys481 and is active in B-cell malignancies driven by mutated MYD88. Mutations in BTKCys481, particularly BTKCys481Ser, are common in patients with acquired ibrutinib resistance. We therefore performed an extensive medicinal chemistry campaign and identified KIN-8194 as a novel dual inhibitor of HCK and BTK. KIN-8194 showed potent and selective in vitro killing of MYD88-mutated lymphoma cells, including ibrutinib-resistant BTKCys481Ser-expressing cells. KIN-8194 demonstrated excellent bioavailability and pharmacokinetic parameters, with good tolerance in rodent models at pharmacologically achievable and active doses. Pharmacodynamic studies showed sustained inhibition of HCK and BTK for 24 hours after single oral administration of KIN-8194 in an MYD88-mutated TMD-8 activated B-cell diffuse large B-cell lymphoma (ABC DLBCL) and BCWM.1 Waldenström macroglobulinemia (WM) xenografted mice with wild-type BTK (BTKWT)- or BTKCys481Ser-expressing tumors. KIN-8194 showed superior survival benefit over ibrutinib in both BTKWT- and BTKCys481Ser-expressing TMD-8 DLBCL xenografted mice, including sustained complete responses of >12 weeks off treatment in mice with BTKWT-expressing TMD-8 tumors. The BCL_2 inhibitor venetoclax enhanced the antitumor activity of KIN-8194 in BTKWT- and BTKCys481Ser-expressing MYD88-mutated lymphoma cells and markedly reduced tumor growth and prolonged survival in mice with BTKCys481Ser-expressing TMD-8 tumors treated with both drugs. The findings highlight the feasibility of targeting HCK, a key driver of mutated MYD88 pro-survival signaling, and provide a framework for the advancement of KIN-8194 for human studies in B-cell malignancies driven by HCK and BTK.

Precision diagnostics in lymphomas - Recent developments and future directions

Genetics is an integral part of the clinical diagnostics of lymphomas that improves disease subclassification and patient risk-stratification. With the introduction of high-throughput sequencing technologies, a rapid, in-depth portrayal of the genomic landscape in major lymphoma entities was achieved. Whilst a few lymphoma entities were characterized by a predominant gene mutation (e.g. Waldenström's macroglobulinemia and hairy cell leukemia), the vast majority demonstrated a very diverse genetic landscape with a high number of recurrent gene mutations (e.g. chronic lymphocytic leukemia and diffuse large B cell lymphoma), indeed reflecting the great clinical heterogeneity among lymphomas. These studies have allowed better understanding of the ontogeny and evolution of different lymphomas, while also identifying new genetic markers that can complement lymphoma diagnostics and improve prognostication. However, despite these efforts, there is still a limited number of gene mutations with predictive impact that can guide treatment selection. In this review, we will highlight clinically relevant diagnostic, prognostic and predictive markers in lymphomas that are used today in routine diagnostics. We will also discuss how comprehensive genomic characterization using broad sequencing panels, allowing for the simultaneous detection of different types of genetic aberrations, may aid future development of precision diagnostics in lymphomas. This may in turn pave the way for the implementation of tailored precision therapy strategies at the individual patient level.

HCK maintains the self-renewal of leukaemia stem cells via CDK6 in AML

Background:

Leukaemia stem cells (LSCs) are responsible for the initiation, maintenance, and recurrence of acute myeloid leukaemia (AML), an aggressive haematological malignancy associated with drug resistance and relapse. Identifying therapeutic LSC targets is critical to curing AML.

Methods

Bioinformatics databases were used to identify therapeutic LSC targets. The conditional knockout mice were used to analyse the role of HCK in leukaemogenesis or normal haematopoiesis. Colony-forming assays, cell counting, and flow cytometry were used to detect the viability and function of leukaemia cells. RT-PCR, western blotting, and RNA sequencing were used to detect mRNA and protein expression.

Result

HCK is expressed at higher levels in LSCs than in haematopoietic stem cells (HSCs), and high HCK levels are correlated with reduced survival time in AML patients. Knockdown of HCK leads to cell cycle arrest, which results in a dramatic decrease in the proliferation and colony formation in human AML cell lines. Moreover, HCK is required for leukemogenesis and leukaemia maintenance in vivo and in vitro. HCK is necessary for the self-renewal of LSCs during serial transplantation and limiting dilution assay. The phenotypes resulting from HCK deficiency can be rescued by CDK6 overexpression in the human cell line. RNA sequencing and gene expression have demonstrated that HCK may sustain cell cycle entry and maintain the self-renewal ability of LSCs through activating the ERK1/2-c-Myc-CDK6 signalling axis. In contrast, HCK deletion does not affect normal haematopoiesis or haematopoietic reconstruction in mice.

Conclusions

HCK maintains the self-renewal of leukaemia stem cells via CDK6 in AML and may be an ideal therapeutic target for eradicating LSCs without influencing normal haematopoiesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02007-4.