Hyper-activation of Aurora kinase a-polo-like kinase 1-FOXM1 axis promotes chronic myeloid leukemia resistance to tyrosine kinase inhibitors

SETD2 loss of function is a recurrent event in advanced-phase chronic myeloid leukemia and contributes to genomic instability: SETD2 loss in Chronic Myeloid Leukemia

The SETD2 tumour suppressor encodes a histone methyltransferase that specifically trimethylates histone H3 on lysine 36 (H3K36me3), a key histone mark implicated in the maintenance of genomic integrity among other functions. We found that SETD2 protein deficiency, mirrored by H3K36me3 deficiency, is a nearly universal event in advanced-phase chronic myeloid leukemia (CML) patients. Similarly, K562 and KCL22 cell lines exhibited markedly reduced or undetectable SETD2/H3K36me3 levels, respectively. This resulted from altered SETD2 protein turnover rather than mutations or transcriptional downregulation, and proteasome inhibition led to the accumulation of hyper-ubiquitinated SETD2 and to H3K36me3 rescue suggesting that a functional SETD2 protein is produced but abnormally degraded. We demonstrated that phosphorylation by Aurora-A kinase and ubiquitination by MDM2 plays a key role in the proteasome-mediated degradation of SETD2. Moreover, we found that SETD2 and H3K36me3 loss impinges on the activation and proficiency of homologous recombination and mismatch repair. Finally, we showed that proteasome and Aurora-A kinase inhibitors, acting via SETD2/H3K36me3 rescue, are effective in inducing apoptosis and reducing clonogenic growth in cell lines and primary cells from advanced-phase patients. Taken together, our results point to SETD2/H3K36me3 deficiency as a mechanism, already identified by our group in systemic mastocytosis, that is reversible, druggable, and BCR::ABL1-independent, able to cooperate with BCR::ABL1 in driving genetic instability in CML. KEY POINTS: Virtually all CML patients in blast crisis display SETD2 loss of function. SETD2 loss seems to be accomplished at the posttranslational level rather than being the result of genetic/genomic hits or transcriptional repression. Phosphorylation by Aurora kinase A and ubiquitination by MDM2 contribute to SETD2 proteasome-mediated degradation in blast crisis CML patients. Loss of SETD2 results in increased DNA damage.

The Functional Transcriptomic Landscape Informs Therapeutic Strategies in Multiple Myeloma

Several therapeutic agents have been approved for treating multiple myeloma, a cancer of bone marrow-resident plasma cells. Predictive biomarkers for drug response could help guide clinical strategies to optimize outcomes. In this study, we present an integrated functional genomic analysis of tumor samples from patients multiple myeloma that were assessed for their ex vivo drug sensitivity to 37 drugs, clinical variables, cytogenetics, mutational profiles, and transcriptomes. This analysis revealed a multiple myeloma transcriptomic topology that generates "footprints" in association with ex vivo drug sensitivity that have both predictive and mechanistic applications. Validation of the transcriptomic footprints for the anti-CD38 mAb daratumumab (DARA) and the nuclear export inhibitor selinexor (SELI) demonstrated that these footprints can accurately classify clinical responses. The analysis further revealed that DARA and SELI have anticorrelated mechanisms of resistance, and treatment with a SELI-based regimen immediately after a DARA-containing regimen was associated with improved survival in three independent clinical trials, supporting an evolutionary-based strategy involving sequential therapy. These findings suggest that this unique repository and computational framework can be leveraged to inform underlying biology and to identify therapeutic strategies to improve treatment of multiple myeloma. Significance: Functional genomic analysis of primary multiple myeloma samples elucidated predictive biomarkers for drugs and molecular pathways mediating therapeutic response, which revealed a rationale for sequential therapy to maximize patient outcomes.

Combination of an aurora kinase inhibitor and the ABL tyrosine kinase inhibitor asciminib against ABL inhibitor-resistant CML cells

The development of BCR::ABL1-targeting tyrosine kinase inhibitors (TKIs) has improved the prognosis of patients with chronic myeloid leukemia (CML). However, resistance to ABL TKIs can develop in CML patients due to BCR::ABL1 point mutations and CML leukemia stem cell (LSC). Aurora kinases are essential kinases for cell division and regulate mitosis, especially the process of chromosomal segregation. Aurora kinase members also promote cancer cell survival and proliferation. This study analyzed whether aurora kinases were regulated in the progression of CML. It also evaluated the efficacy of the ABL TKI asciminib and the aurora kinase inhibitor LY3295668. The expressions of AURKA and AURKB were higher in the CML cells compared with normal cells using a public database (GSE100026). Asciminib or LY3295668 alone inhibited CML cells after 72 h, and cellular cytotoxicity was increased. The combined use of Asciminib and LY3295668 increased superior efficacy compared with either drug alone. Colony formation was reduced by cotreatment with asciminib and LY3295668. In the cell-cycle analyses, LY3295668 induced G2/M arrest. Cell populations in the sub-G1 phase were observed when cotreating with asciminib and LY3295668. The combination treatment also changed the mitochondrial membrane potential. In addition, AURKA shRNA transfectant cells had increased asciminib sensitivity. Combining asciminib and aurora kinase inhibition enhanced the efficacy and is proposed as a new therapeutic option for patients with CML. These findings have clinical implications for a potential novel therapeutic strategy for CML patients.

Polo-like kinase-1, Aurora kinase A and WEE1 kinase are promising druggable targets in CML cells displaying BCR::ABL1-independent resistance to tyrosine kinase inhibitors

In chronic myeloid leukemia (CML), Aurora kinase A and Polo like kinase 1 (PLK1), two serine-threonine kinases involved in the maintenance of genomic stability by preserving a functional G2/M checkpoint, have been implicated in BCR::ABL1-independent resistance to the tyrosine kinase inhibitor (TKI) imatinib mesylate and in leukemic stem cell (LSC) persistence. It can be speculated that the observed deregulated activity of Aurora A and Plk1 enhances DNA damage, promoting the occurrence of additional genomic alterations contributing to TKI resistance and ultimately driving progression from chronic phase to blast crisis (BC). In this study, we propose a new therapeutic strategy based on the combination of Aurora kinase A or PLK1 inhibition with danusertib or volasertib, respectively, and WEE1 inhibition with AZD1775. Danusertib and volasertib used as single drugs induced apoptosis and G2/M-phase arrest, associated with accumulation of phospho-WEE1. Subsequent addition of the WEE1 inhibitor AZD1775 in combination significantly enhanced the induction of apoptotic cell death in TKI-sensitive and -resistant cell lines as compared to both danusertib and volasertib alone and to the simultaneous combination. This schedule indeed induced a significant increase of the DNA double-strand break marker γH2AX, forcing the cells through successive replication cycles ultimately resulting in apoptosis. Finally, combination of danusertib or volasertib+AZD1775 significantly reduced the clonogenic potential of CD34+ CML progenitors from BC patients. Our results may have implications for the development of innovative therapeutic approaches aimed to improve the outcomes of patients with multi-TKI-resistant or BC CML.

Phosphorylation-Dependent Regulation of WNT/Beta-Catenin Signaling

WNT/β-catenin signaling is a highly complex pathway that plays diverse roles in various cellular processes. While WNT ligands usually signal through their dedicated Frizzled receptors, the decision to signal in a β-catenin-dependent or -independent manner rests upon the type of co-receptors used. Canonical WNT signaling is β-catenin-dependent, whereas non-canonical WNT signaling is β-catenin-independent according to the classical definition. This still holds true, albeit with some added complexity, as both the pathways seem to cross-talk with intertwined networks that involve the use of different ligands, receptors, and co-receptors. β-catenin can be directly phosphorylated by various kinases governing its participation in either canonical or non-canonical pathways. Moreover, the co-activators that associate with β-catenin determine the output of the pathway in terms of induction of genes promoting proliferation or differentiation. In this review, we provide an overview of how protein phosphorylation controls WNT/β-catenin signaling, particularly in human cancer.

Overcoming Resistance to Kinase Inhibitors: The Paradigm of Chronic Myeloid Leukemia

Protein kinases (PKs) play crucial roles in cellular proliferation and survival, hence their deregulation is a common event in the pathogenesis of solid and hematologic malignancies. Targeting PKs has been a promising strategy in cancer treatment, and there are now a variety of approved anticancer drugs targeting PKs. However, the phenomenon of resistance remains an obstacle to be addressed and overcoming resistance is a goal to be achieved. Chronic myeloid leukemia (CML) is the first as well as one of the best examples of a cancer that can be targeted by molecular therapy; hence, it can be used as a model disease for other cancers. This review aims to summarize up-to-date knowledge on the main mechanisms implicated in resistance to PK inhibitory therapies and to outline the main strategies that are being explored to overcome resistance. The importance of molecular diagnostics and disease monitoring in counteracting resistance will also be discussed.

A narrative review of research progress on FoxM1 in breast cancer carcinogenesis and therapeutics

OBJECTIVE

The purpose of this review is to clarify the potential roles of forkhead box transcription factor M1 (FoxM1) in the occurrence and progression of breast cancer, as well as the predictive value of FoxM1 as a prognostic biomarker and potential therapeutic target for breast cancer.

BACKGROUND

Breast cancer, well-known as a molecularly heterogeneous cancer, is still one of the most frequently diagnosed malignant tumors among females worldwide. Tumor recurrence and metastasis are the central causes of high mortality in breast cancer patients. Many factors contribute to the occurrence and progression of breast cancer, including FoxM1. FoxM1, widely regarded as a classic proliferation-related transcription factor, plays pivotal roles in the occurrence, proliferation, invasion, migration, drug resistance, and epithelial-mesenchymal transition (EMT) processes of multiple human tumors including breast cancer.

METHODS

The PubMed database was searched for articles published in English from February 2008 to May 2021 using related keywords such as "forkhead box transcription factor M1", "human breast cancer", "FoxM1", and "human tumor". About 90 research papers and reports written in English were identified, most of which were published after 2015. These papers mainly concentrated on the functions of FoxM1 in the occurrence, development, drug resistance, and treatment of human breast cancer.

CONCLUSIONS

Considering that the abnormal expression of FoxM1 plays a significant role in the proliferation, invasion, metastasis, and chemotherapy drug resistance of breast cancer, and its overexpression is closely correlated with the unfavorable clinicopathological characteristics of breast tumor patients, it is considerably important to comprehend the regulatory mechanism of FoxM1 in breast cancer. This will provide strong evidence for FoxM1 as a potential biomarker for the targeted treatment and prognostic evaluation of breast cancer patients.

Current Views on the Interplay between Tyrosine Kinases and Phosphatases in Chronic Myeloid Leukemia

Simple Summary

The chromosomal alteration t(9;22) generating the BCR-ABL1 fusion protein represents the principal feature that distinguishes some types of leukemia. An increasing number of articles have focused the attention on the relevance of protein phosphatases and their potential role in the control of BCR-ABL1-dependent or -independent signaling in different areas related to the biology of chronic myeloid leukemia. Herein, we discuss how tyrosine and serine/threonine protein phosphatases may interact with protein kinases, in order to regulate proliferative signal cascades, quiescence and self-renewals on leukemic stem cells, and drug-resistance, indicating how BCR-ABL1 can (directly or indirectly) affect these critical cells behaviors. We provide an updated review of the literature on the function of protein phosphatases and their regulation mechanism in chronic myeloid leukemia.

Abstract

Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by BCR-ABL1 oncogene expression. This dysregulated protein-tyrosine kinase (PTK) is known as the principal driver of the disease and is targeted by tyrosine kinase inhibitors (TKIs). Extensive documentation has elucidated how the transformation of malignant cells is characterized by multiple genetic/epigenetic changes leading to the loss of tumor-suppressor genes function or proto-oncogenes expression. The impairment of adequate levels of substrates phosphorylation, thus affecting the balance PTKs and protein phosphatases (PPs), represents a well-established cellular mechanism to escape from self-limiting signals. In this review, we focus our attention on the characterization of and interactions between PTKs and PPs, emphasizing their biological roles in disease expansion, the regulation of LSCs and TKI resistance. We decided to separate those PPs that have been validated in primary cell models or leukemia mouse models from those whose studies have been performed only in cell lines (and, thus, require validation), as there may be differences in the manner that the associated pathways are modified under these two conditions. This review summarizes the roles of diverse PPs, with hope that better knowledge of the interplay among phosphatases and kinases will eventually result in a better understanding of this disease and contribute to its eradication.

Foretinib induces G2/M cell cycle arrest, apoptosis, and invasion in human glioblastoma cells through c-MET inhibition

PURPOSE

Glioblastoma multiforme (GBM) is one of the most aggressive human cancers. The c-MET receptor tyrosine kinase (RTK) which is frequently deregulated in GBM is considered as a promising target for GBM treatment. The c-MET plays a key role in cell proliferation, cell cycle progression, invasion, angiogenesis, and metastasis. Here, we investigated the anti-tumour activity of foretinib, a c-MET inhibitor, on three human GBM cells (T98G, U87MG and U251).

METHODS

Anti-proliferative effect of foretinib was determined using MTT, crystal violet staining, and clonogenic assays. PI and Annexin V/PI staining flow cytometry were used to evaluate the effects of foretinib on cell cycle and apoptosis, respectively. Scratch assay, qRT-PCR, western blot, and zymography analyses were applied to elucidate the molecular mechanisms underlying the anti-tumour activity of foretinib.

RESULTS

Foretinib treatment reduced phosphorylation of c-MET on T98G and U251 cells, but not in U87MG cells. The highest inhibitory effect was observed in T98G cells (IC₅₀ = 4.66 ± 0.29 µM) and the lowest one in U87MG cells (IC₅₀ = 29.99 ± 1.31 µM). The results showed that foretinib inhibited the proliferation of GBM cells through a G2/M cell cycle arrest and mitochondrial-mediated apoptosis in association with alternation in expression of the related genes and protein-regulated G2/M phase and apoptosis. Foretinib diminished GBM cell invasion through downregulation of the proteolytic cascade of MMP2, uPA and uPAR and epithelial-mesenchymal transition (EMT)-related genes. A different GBM cell sensitivity pattern was noticeable in all experiments which demonstrated T98G as a sensitive and U87MG as a resistant phenotype to foretinib treatment.

CONCLUSION

The results indicated that foretinib might have the therapeutic potential against human GBM which deserve further investigation.

Knockdown of AURKA sensitizes the efficacy of radiation in human colorectal cancer

AIMS

Abnormally amplified expression of AURKA (aurora kinase A) is closely related to chemo-resistance in human colorectal cancer, lung cancer and leukemia. However, the biological role of AURKA in response to radio-sensitivity in human colorectal cancer is still unknown. Therefore, we evaluated the radio-sensitize ability of perturbation AURKA in human colorectal cancer.

MAIN METHODS

The knockdown effect of shAURKA was determined by western blot and qRT-PCR, respectively. Cell growth was determined by CCK-8 and clonogenic assay. Cell migration and metastasis was measured by wound healing assay and transwell invasive assay, respectively. Cell cycle and apoptosis was analyzed by flow cytometry. The alteration of down-stream targets was determined by western blot analysis.

KEY FINDINGS

We observed that high-level of AURKA expression is associated with poor prognosis in CRC patients receiving radiotherapy. Knockdown of AURKA significantly sensitizes the efficacy of radiation on the proliferation of HCT116 and HT-29 cells. The combination of AURKA inhibition and radiation could effectively suppress the ability of cell migration and metastasis, but also synergistically induce cellular apoptosis and arrest cell cycle at G2/M phase. Further studies demonstrated that knockdown AURKA markedly enhanced the efficacy of radiation through elevated PARP cleavage and induced AURKA-mediated pro-apoptosis factor BIM. Meanwhile, knockdown of AURKA in combination with radiation synergistically suppressed the regulator in blockage of G2/M phase, CDK2.

SIGNIFICANCE

Taken together, our results provide the evidence that targeted inhibition of AURKA could be a promising strategy for enhancing the efficacy of radiation for the treatment of human colorectal cancer.

Identification of Aurora Kinase A as a Biomarker for Prognosis in Obesity Patients with Early Breast Cancer

BACKGROUND

Obesity is associated both with a higher risk of developing breast cancer, particularly in postmenopausal women, and with worse disease outcome for women of all ages. Previous investigation suggested Aurora A kinase was able to partially restore the functionalities of obese adipose-derived mesenchymal stem cells by stabilizing their primary cilia and reestablishing a balance of multiple stemness-associated genes. The association between Aurora A and obesity breast cancer is still unclear. We hypothesized that overexpression of Aurora A was associated with poor survival in obesity breast cancer and the related axis mechanism was involved.

METHODS

A total of 517 primary breast cancer specimens were collected from the First Affiliated Hospital of China Medical University between January 2011 and November 2016. Our independent variable was BMI at baseline, categorized as overweight (BMI ≥25 kg/m2, as obesity cohort), and normal (18.5 ≤ BMI <25 kg/m2, as non-obesity cohort). The immunohistochemical (IHC) staining was performed with Aurora A, Survivin, MMP11, Cyclin B1, and Cathepsin L. Kaplan-Meier curve was used to analyze overall survival in our cohorts and TCGA-BRCA data (GSE3494). Log rank test was used to calculate P values. Protein-protein interaction (PPI) network analysis and MCODE model were used to analyze the Aurora-altered signal pathway from GSE78958.

RESULTS

Among 517 breast patients, Aurora A-positive (staining scores ≥4) was significantly higher in obesity breast carcinoma compared with non-obesity cancer carcinoma (χ 2=9.79, P=0.002), with more frequency in hormone receptor-negative (68.4% vs 77.9%, P=0.015) and HER2-positive patients (28.7% vs 17.9%, P=0.003). High Aurora A expression was remarkably and significantly associated with overall survival (OS) (8-year OS ratio: 69.5% vs 81.1%, OR=1.76, 95% CI: 1.03~3.02, P=0.041) in obesity cohort. Interestingly, higher expression of Aurora A was not associated with a shorter overall survival time among the non-obesity breast cancer (8-year OS ratio: 81.4% vs 85.8%, OR=1.40, 95% CI: 0.79~2.45, P=0.229). As for RFS, the expression levels of Aurora A expression genes have no significance with RFS statistically in non-obesity and obesity patients. Aurora A and lymph node metastases were significantly poor prognostic factors for OS, and borderline significance was noted for high BMI. Kaplan-Meier survival analysis from TCGA database confirmed that the high Aurora A expression group had worse prognosis (HR=1.47, 95% CI: 1.14-1.90, P=0.003). The KEGG pathway enrichment results were consistent with GO biological process term analysis, in which CCNB1 was enriched for upregulated Aurora A. In our samples, Aurora A level on tumor cytoplasm had broad connections with Cyclin B1 by IHC correlation analysis (correlation coefficient = 0.227, P=0.001).

CONCLUSION

Our finding demonstrates here for the first time that high expression of Aurora A was notably correlated with early recurrence and poor overall survival in obesity patients with early breast cancer. The Aurora A-Cyclin B1 axis could be a potential promising therapeutic target for cancer intervention and therapy.

Revisiting β-Catenin Signaling in T-Cell Development and T-Cell Acute Lymphoblastic Leukemia

β-Catenin/CTNNB1 is critical for leukemia initiation or the stem cell capacity of several hematological malignancies. This review focuses on a general evaluation of β-catenin function in normal T-cell development and T-cell acute lymphoblastic leukemia (T-ALL). The integration of the existing literature offers a state-of-the-art dissection of the complexity of β-catenin function in leukemia initiation and maintenance in both Notch-dependent and independent contexts. In addition, β-catenin mutations are screened for in T-ALL primary samples, and it is found that they are rare and with little clinical relevance. Transcriptional analysis of Wnt family members (Ctnnb1, Axin2, Tcf7, and Lef1) and Myc in different publicly available T-ALL cohorts indicates that the expression of these genes may correlate with T-ALL subtypes and/or therapy outcomes.