PBK/TOPK promotes tumour cell proliferation through p38 MAPK activity and regulation of the DNA damage response

PDZ-Binding Kinase, a Novel Regulator of Vascular Remodeling in Pulmonary Arterial Hypertension

BACKGROUND

Pulmonary arterial hypertension (PAH) is high blood pressure in the lungs that originates from structural changes in small resistance arteries. A defining feature of PAH is the inappropriate remodeling of pulmonary arteries (PA) leading to right ventricle failure and death. Although treatment of PAH has improved, the long-term prognosis for patients remains poor, and more effective targets are needed.

METHODS

Gene expression was analyzed by microarray, RNA sequencing, quantitative polymerase chain reaction, Western blotting, and immunostaining of lung and isolated PA in multiple mouse and rat models of pulmonary hypertension (PH) and human PAH. PH was assessed by digital ultrasound, hemodynamic measurements, and morphometry.

RESULTS

Microarray analysis of the transcriptome of hypertensive rat PA identified a novel candidate, PBK (PDZ-binding kinase), that was upregulated in multiple models and species including humans. PBK is a serine/threonine kinase with important roles in cell proliferation that is minimally expressed in normal tissues but significantly increased in highly proliferative tissues. PBK was robustly upregulated in the medial layer of PA, where it overlaps with markers of smooth muscle cells. Gain-of-function approaches show that active forms of PBK increase PA smooth muscle cell proliferation, whereas silencing PBK, dominant negative PBK, and pharmacological inhibitors of PBK all reduce proliferation. Pharmacological inhibitors of PBK were effective in PH reversal strategies in both mouse and rat models, providing translational significance. In a complementary genetic approach, PBK was knocked out in rats using CRISPR/Cas9 editing, and loss of PBK prevented the development of PH. We found that PBK bound to PRC1 (protein regulator of cytokinesis 1) in PA smooth muscle cells and that multiple genes involved in cytokinesis were upregulated in experimental models of PH and human PAH. Active PBK increased PRC1 phosphorylation and supported cytokinesis in PA smooth muscle cells, whereas silencing or dominant negative PBK reduced cytokinesis and the number of cells in the G2/M phase of the cell cycle.

CONCLUSIONS

PBK is a newly described target for PAH that is upregulated in proliferating PA smooth muscle cells, where it contributes to proliferation through changes in cytokinesis and cell cycle dynamics to promote medial thickening, fibrosis, increased PA resistance, elevated right ventricular systolic pressure, right ventricular remodeling, and PH.

TOPK promotes the development of psoriasis and worenine alleviates psoriasiform dermatitis by inhibiting TOPK activity

BACKGROUND

Psoriasis is an inflammatory skin disease. The pathogenesis of psoriasis has not been fully elucidated. T-lymphokine-activated killer cell-originated protein kinase (TOPK) activity increases in a proinflammatory environment, and inhibiting TOPK blocks inflammation. However, whether TOPK is involved in the pathogenesis of psoriasis remains to be identified.

OBJECTIVES

We aimed to study the role of TOPK in psoriasis and attempted to find a drug targeting TOPK for the prevention and treatment of psoriasis.

METHOD

Firstly, the expressions of TOPK in psoriatic patients, psoriatic cell and animal model were analysed by Gene Expression Omnibus database, immunohistochemistry (IHC) staining and western blot (WB). After inhibiting TOPK by chemical or gene knockout, the effect of TOPK on the development of psoriasis was verified in cell and animal model by WB, qRT-PCR, ELISA, haematoxylin-eosin (H&E) and IHC staining. Moreover, phosphoproteomic analysis was performed to explore the signalling pathways regulated by TOPK in the occurrence and development of psoriasis. Then, an in vitro kinase assay was performed to prove TOPK kinase activity was inhibited by worenine. Ultimately, WB, qRT-PCR, ELISA, H&E and IHC staining were used to verify the anti-psoriasis effect of worenine by inhibiting TOPK was in cell and animal model.

RESULTS

In this study, we found that TOPK was highly expressed in psoriasis patients, psoriatic cell and animal model, which suggests that TOPK might be associated with psoriasis pathogenesis. Interestingly, chemical or genetic inhibition of TOPK alleviated M5- and imiquimod (IMQ)-induced psoriasis-like dermatitis, which further confirmed the role of TOPK in promoting the development of psoriasis. Moreover, we determined that worenine inhibited TOPK kinase activity. In addition, worenine relieved M5- and IMQ-induced psoriasiform dermatitis by inhibiting TOPK activity.

CONCLUSIONS

T-lymphokine-activated killer cell-originated protein kinase promotes the development of psoriasis. Therefore, TOPK might be a promising drug target for the prevention and treatment of psoriasis. Worenine alleviates psoriasiform dermatitis by inhibiting TOPK activity, providing new strategies for clinical intervention.

Machine-learning-based classification of diffuse large B-cell lymphoma patients by a 7-mRNA signature enriched with immune infiltration and cell cycle

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) exhibits remarkable heterogeneity but still remains undiagnosed in identifying the subpopulation of DLBCL to predict the prognosis and guide clinical treatment.

METHODS

Molecular subgroups were identified in gene expression data from GSE10846 by a consensus clustering algorithm. And gene set enrichment analysis, immune infiltration, and the proposed cell cycle algorithm were applied to explore the biological functions of different subtypes. Meanwhile, univariate and multivariate Cox regression analyses were used to evaluate independent prognostic factors of DLBCL. Finally, the prognostic model, including some key genes screened by Lasso regression, Random Forest algorithm, and point-biserial correlation, was constructed by an optimal classifier from seven machine learning algorithms and validated by another three external datasets (GSE34171, GSE87371, GSE31312).

RESULTS

Comprehensive genomic analysis of 1,143 DLBCL samples identify 2 molecularly, prognostically relevant subtypes: immune-enriched (IME) and cell-cycle-enriched (CCE). Then a new predictive model including seven key genes (SERPING1, TIMP2, NME1, DCTPP1, RFC4, POLE2, and SNRPD1) was developed with high prediction accuracy (88.6%) and strong predictive power (AUC = 0.973) based on the Support Vector Machine (SVM) algorithm in 414 patients from GSE10846. The predictive power was similar in another three testing sets (HR > 1.400, p < 0.05).

CONCLUSION

This model could evaluate survival independently with strong predictive power compared with other clinical risk factors. Our study constructed a reliable model to predict two new subtypes of DLBCL patients, which could guide the implementation of individualized treatment.

FHND004 inhibits malignant proliferation of multiple myeloma by targeting PDZ-binding kinase in MAPK pathway

Inhibitors of Epidermal growth factor receptor tyrosine kinase (EGFR-TKIs) are producing impressive benefits to responsive types of cancers but challenged with drug resistances. FHND drugs are newly modified small molecule inhibitors based on the third-generation EGFR-TKI AZD9291 (Osimertinib) that are mainly for targeting the mutant-selective EGFR, particularly for the non-small cell lung cancer (NSCLC). Successful applications of EGFR-TKIs to other cancers are less certain, thus the present pre-clinical study aims to explore the anticancer effect and downstream targets of FHND in multiple myeloma (MM), which is an incurable hematological malignancy and reported to be insensitive to first/second generation EGFR-TKIs (Gefitinib/Afatinib). Cell-based assays revealed that FHND004 and FHND008 significantly inhibited MM cell proliferation and promoted apoptosis. The RNA-seq identified the involvement of the MAPK signaling pathway. The protein chip screened PDZ-binding kinase (PBK) as a potential drug target. The interaction between PBK and FHND004 was verified by molecular docking and microscale thermophoresis (MST) assay with site mutation (N124/D125). Moreover, the public clinical datasets showed high expression of PBK was associated with poor clinical outcomes. PBK overexpression evidently promoted the proliferation of two MM cell lines, whereas the FHND004 treatment significantly inhibited survival of 5TMM3VT cell-derived model mice and growth of patient-derived xenograft (PDX) tumors. The mechanistic study showed that FHND004 downregulated PBK expression, thus mediating ERK1/2 phosphorylation in the MAPK pathway. Our study not only demonstrates PBK as a promising novel target of FHND004 to inhibit MM cell proliferation, but also expands the EGFR kinase-independent direction for developing anti-myeloma therapy.

Specific Regulation of m6A by SRSF7 Promotes the Progression of Glioblastoma

Serine/arginine-rich splicing factor 7 (SRSF7), a known splicing factor, has been revealed to play oncogenic roles in multiple cancers. However, the mechanisms underlying its oncogenic roles have not been well addressed. Here, based on N6-methyladenosine (m6A) co-methylation network analysis across diverse cell lines, we find that the gene expression of SRSF7 is positively correlated with glioblastoma (GBM) cell-specific m6A methylation. We then indicate that SRSF7 is a novel m6A regulator, which specifically facilitates the m6A methylation near its binding sites on the mRNAs involved in cell proliferation and migration, through recruiting the methyltransferase complex. Moreover, SRSF7 promotes the proliferation and migration of GBM cells largely dependent on the presence of the m6A methyltransferase. The two m6A sites on the mRNA for PDZ-binding kinase (PBK) are regulated by SRSF7 and partially mediate the effects of SRSF7 in GBM cells through recognition by insulin-like growth factor 2 mRNA-binding protein 2 (IGF2BP2). Together, our discovery reveals a novel role of SRSF7 in regulating m6A and validates the presence and functional importance of temporal- and spatial-specific regulation of m6A mediated by RNA-binding proteins (RBPs).

Xanthohumol inhibits non-small cell lung cancer via directly targeting T-lymphokine-activated killer cell-originated protein kinase

Xanthohumol is a principal prenylated chalcone isolated from hops. Previous studies have shown that xanthohumol was effective against various types of cancer, but the mechanisms, especially the direct targets for xanthohumol to exert an anticancer effect, remain elusive. Overexpression of T-lymphokine-activated killer cell-originated protein kinase (TOPK) promotes tumorigenesis, invasion and metastasis, implying the likely potential for targeting TOPK in cancer prevention and treatment. In the present study, we found that xanthohumol significantly inhibited the cell proliferation, migration and invasion of non-small cell lung cancer (NSCLC) in vitro and suppressed tumor growth in vivo, which is well correlated with inactivating TOPK, evidenced by reduced phosphorylation of TOPK and its downstream signaling histone H3 and Akt, and decreased its kinase activity. Moreover, molecular docking and biomolecular interaction analysis showed that xanthohumol was able to directly bind to the TOPK protein, suggesting that TOPK inactivation by xanthohumol is attributed to its ability to directly interact with TOPK. The findings of the present study identified TOPK as a direct target for xanthohumol to exert its anticancer activity, revealing novel insight into the mechanisms underlying the anticancer activity of xanthohumol.

The therapeutic potential value of Cancer-testis antigens in immunotherapy of gastric cancer

Gastric cancer (GC) is the fourth most common cause of mortality and the fifth for incidence, globally. Diagnosis, early prognosis, and therapy remains challenging for this condition, and new tumor-associated antigens are required for its detection and immunotherapy. Cancer-testis antigens (CTAs) are a subfamily of tumor-associated antigens (TAAs) that have been identified as potential biomarkers and targets for cancer immunotherapy. The CTAs-restricted expression pattern in tumor cells and their potential immunogenicity identify them as attractive target candidates in CTA-based diagnosis or prognosis or immunotherapy. To date, numerous studies have reported the dysregulation of CTAs in GC. Several clinical trials have been done to assess CTA-based immunotherapeutic potential in the treatment of GC patients. NY-ESO-1, MAGE, and KK-LC-1 have been used in GC clinical trials. We review recent studies that have investigated the potential of the CTAs in GC regarding the expression, function, aggressive phenotype, prognosis, and immunological responses as well as their possible clinical significance as immunotherapeutic targets with a focus on challenges and future interventions.

Markov State Models Underlying the N-Terminal Premodel of TOPK/PBK

Lymphokine-activated killer T-cell-originated protein kinase (TOPK) is a potential target for cancer therapy. To explore the micromechanism, we proposed the N-terminal premodel (NTPM) of the TOPK monomer via homology modeling and molecular dynamic simulations and analyzed the conformational dynamics by Markov state model analysis. The electronegative insert (ENI) motif of the NTPM can be opened with a small probability under wild type, regulated by the so-called "N-C" interaction zone consisting of the N-terminal head, the coil between β₃-strand and αC-helix, and the ENI motif. Glutamate substitution at threonine residue 9 or tyrosine residue 74 promotes the closed-open transition, revealing the details of phosphorylation. Allosteric effects induce functionally relevant structural changes, such as increased structural flexibility and active sites, which are thought to be necessary for further activation or binding. These findings provide rational structural templates for designing state-dependent inhibitors and give insight into the molecular regulatory mechanisms of TOPK monomers.

Overexpression of PBK/TOPK relates to poor prognosis of patients with breast cancer: a retrospective analysis

Background

PDZ-binding kinase/T-lymphokine-activated killer cell-derived protein kinase (PBK/TOPK) is a potential prognostic indicator for patients with breast cancer. The objective of the present study was to explore the relationship between PBK/TOPK expression and clinicopathological indicators as well as the survival of patients with breast cancer.

Methods

Immunohistochemical staining was used to detect the expression of PBK/TOPK in 202 cases of breast cancer tissues. The relationship between PBK/TOPK and clinicopathological parameters was evaluated using Spearman’s rank-order correlation. The difference in PBK/TOPK expression among different molecular types was analyzed with the chi-square test. Kaplan-Meier analysis was used to create a survival curve and the log rank test was used to analyze the overall survival (OS) and disease-free survival (DFS). Prognostic correlation was assessed using univariate and multivariate Cox regression analyses.

Results

Among 202 breast cancer samples, PBK/TOPK was expressed (“+” and “++”) in 182 samples (90.1%). In addition, the histological grade, TNM stages, lymph node metastasis, estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER-2), and Ki-67 were positively associated with PBK/TOPK expression. With regard to the molecular type, the expression of PBK/TOPK is different. The expression level of PBK/TOPK was negatively correlated with both the OS and DFS of breast cancer patients. The difference in the above results is meaningful (P < 0.05).

Conclusions

PBK/TOPK is overexpressed in breast cancer, and the expression is closely related to the clinicopathological characteristics of the disease. Breast cancer patients with high expression of PBK/TOPK have a poor prognosis. Therefore, healthcare providers can optimize breast cancer management using this indicator.

Identification of PBK as a hub gene and potential therapeutic target for medulloblastoma

Medulloblastoma (MB) is the most frequent malignant brain tumor in pediatrics. Since the current standard of care for MB consisting of surgery, cranio-spinal irradiation and chemotherapy often leads to a high morbidity rate, a number of patients suffer from long-term sequelae following treatment. Targeted therapies hold the promise of being more effective and less toxic. Therefore, the present study aimed to identify hub genes with an upregulated expression in MB and to search for potential therapeutic targets from these genes. For this purpose, gene expression profile datasets were obtained from the Gene Expression Omnibus database and processed using R 3.6.0 software to screen differentially expressed genes (DEGs) between MB samples and normal brain tissues. A total of 282 upregulated and 436 downregulated DEGs were identified. Functional enrichment analysis revealed that the upregulated DEGs were predominantly enriched in the cell cycle, DNA replication and cell division. The top 10 hub genes were identified from the protein-protein interaction network of upregulated genes, and one identified hub gene [PDZ binding kinase (PBK)] was selected for further investigation due to its possible role in the pathogenesis of MB. The aberrant expression of PBK in MB was verified in additional independent gene expression datasets. Survival analysis demonstrated that a higher expression level of PBK was significantly associated with poorer clinical outcomes in non-Wingless MBs. Furthermore, targeting PBK with its inhibitor, HI-TOPK-032, impaired the proliferation and induced the apoptosis of two MB cell lines, with the diminished phosphorylation of downstream effectors of PBK, including ERK1/2 and Akt, and the activation of caspase-3. Hence, these results suggest that PBK may be a potential prognostic biomarker and a novel candidate of targeted therapy for MB.

PBK/TOPK Is a Favorable Prognostic Biomarker Correlated with Antitumor Immunity in Colon Cancers

Immune checkpoint inhibitor therapy has proven efficacy in a subset of colon cancer patients featuring a deficient DNA mismatch repair system or a high microsatellite instability profile. However, there is high demand for more effective biomarkers to expand the colon cancer population responding to ICI therapy. PBK/TOPK, a serine/threonine kinase, plays a role in cell cycle regulation and mitotic progression. Here, we investigated the correlation between PBK/TOPK expression and tumor immunity and its prognostic value in colon cancer. Based on large-scale bioinformatics analysis, we discovered that elevated PBK/TOPK expression predicted a favorable outcome in patients with colon cancer and was positively associated with immune infiltration levels of CD8+ T cells, CD4+ T cells, natural killer cells, and M1 macrophages. In contrast, a negative correlation was found between PBK/TOPK expression and immune suppressor cells, including regulatory T cells and M2 macrophages. Furthermore, the expression of PBK/TOPK was correlated with the expression of T-cell cytotoxicity genes in colon cancer. Additionally, high PBK/TOPK expression was associated with mutations in DNA damage repair genes, and thus with increased tumor mutation and neoantigen burden. These findings suggest that PBK/TOPK may serve as a prognostic and predictive biomarker for immunotherapy in colon cancer.

The role of T-LAK cell-originated protein kinase in targeted cancer therapy

Targeted therapy has gradually become the first-line clinical tumor therapy due to its high specificity and low rate of side effects. TOPK (T-LAK cell-originated protein kinase), a MAP kinase, is highly expressed in various tumor tissues, while it is rarely expressed in normal tissues, with the exceptions of testicular germ cells and some fetal tissues. It can promote cancer cell proliferation and migration and is also related to drug resistance. Therefore, TOPK is considered a good therapeutic target. Moreover, a number of studies have shown that targeting TOPK can inhibit the proliferation of cancer cells and promote their apoptosis. Here, we discussed the biological functions of TOPK in cancer and summarized its tumor-related signaling network and known TOPK inhibitors. Finally, the role of TOPK in targeted cancer therapy was concluded, and future research directions for TOPK were assessed.

Non-Coding RNAs Associated With Radioresistance in Triple-Negative Breast Cancer

The resistance that Triple-Negative Breast Cancer (TNBC), the most aggressive breast cancer subtype, develops against radiotherapy is a complex phenomenon involving several regulators of cell metabolism and gene expression; understanding it is the only way to overcome it. We focused this review on the contribution of the two leading classes of regulatory non-coding RNAs, microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), against ionizing radiation-based therapies. We found that these regulatory RNAs are mainly associated with DNA damage response, cell death, and cell cycle regulation, although they regulate other processes like cell signaling and metabolism. Several regulatory RNAs regulate multiple pathways simultaneously, such as miR-139-5p, the miR-15 family, and the lncRNA HOTAIR. On the other hand, proteins such as CHK1 and WEE1 are targeted by several regulatory RNAs simultaneously. Interestingly, the study of miRNA/lncRNA/mRNA regulation axes increases, opening new avenues for understanding radioresistance. Many of the miRNAs and lncRNAs that we reviewed here can be used as molecular markers or targeted by upcoming therapeutic options, undoubtedly contributing to a better prognosis for TNBC patients.

TOPK: A new predictor of the therapeutic response to neoadjuvant chemotherapy and prognosis in triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) has a high probability of relapse and poor overall survival. Neoadjuvant chemotherapy (NACT) is currently a routine treatment strategy for TNBC, but some patients do not respond well. T-LAK cell-originated protein kinase (TOPK) is highly expressed in breast cancer cells and contributes to cancer cell proliferation. The present study aimed to investigate the correlation of TOPK expression with NACT treatment response and prognosis in TNBC.

METHODS

We collected 66 pairs of TNBC samples before and after NACT with docetaxel+ epirubicin+ cyclophosphamide (TEC). The Miller-Payne (MP) system was used to assess the therapeutic response to NACT in TNBC patients.

RESULTS

Immunohistochemistry analysis showed that TNBC patients with high TOPK expression before NACT had a poor treatment response and a poor prognosis. The expression of TOPK after NACT was significantly higher than that before NACT in patients with MP grade 1-3. In contrast, patients with MP grade 4-5 had significantly lower TOPK expression after NACT than before NACT, and the expression change in Ki-67 in patients with MP grade 4-5 exhibited the same trend. Survival analysis revealed that patients with TNBC accompanied by elevated TOPK expression before NACT had a worse prognosis than those with lower TOPK expression.

CONCLUSION

TOPK may be a novel predictor for the therapeutic response to NACT and prognosis for patients with TNBC.

T-LAK cell-originated protein kinase (TOPK): an emerging prognostic biomarker and therapeutic target in osteosarcoma

T-lymphokine-activated killer (T-LAK) cell-originated protein kinase (TOPK) is an emerging target with critical roles in various cancers; however, its expression and function in osteosarcoma remain unexplored. We evaluated TOPK expression using RNA sequencing and gene expression data from public databases (TARGET-OS, CCLE, GTEx, and GENT2) and immunohistochemistry in an osteosarcoma tissue microarray (TMA). TOPK gene expression was significantly higher in osteosarcoma than normal tissues and directly correlated with shorter overall survival. TOPK was overexpressed in 83.3% of the osteosarcoma specimens within our TMA and all osteosarcoma cell lines, whereas normal osteoblast cells had no aberrant expression. High expression of TOPK associated with metastasis, disease status, and shorter overall survival. Silencing of TOPK with small interfering RNA (siRNA) decreased cell viability, and inhibition with the selective inhibitor OTS514 suppressed osteosarcoma cell proliferation, migration, colony-forming ability, and spheroid growth. Enhanced chemotherapeutic sensitivity and a synergistic effect were also observed with the combination of OTS514 and either doxorubicin or cisplatin in osteosarcoma cell lines. Taken together, our study demonstrated that TOPK is a potential prognostic biomarker and therapeutic target for osteosarcoma treatment.

PBK/TOPK: An Effective Drug Target with Diverse Therapeutic Potential

Simple Summary

Cancer is a major public health problem worldwide, and addressing its morbidity, mortality, and prevalence is the first step towards appropriate control measures. Over the past several decades, many pharmacologists have worked to identify anti-cancer targets and drug development strategies. Within this timeframe, many natural compounds have been developed to inhibit cancer growth by targeting kinases, such as AKT, AURKA, and TOPK. Kinase assays and computer modeling are considered to be effective and powerful tools for target screening, as they can predict physical interactions between small molecules and their bio-molecular targets. In the present review, we summarize the inhibitors and compounds that target TOPK and describe its role in cancer progression. The extensive body of research that has investigated the contribution of TOPK to cancer suggests that it may be a promising target for cancer therapy.

Abstract

T-lymphokine-activated killer cell-originated protein kinase (TOPK, also known as PDZ-binding kinase or PBK) plays a crucial role in cell cycle regulation and mitotic progression. Abnormal overexpression or activation of TOPK has been observed in many cancers, including colorectal cancer, triple-negative breast cancer, and melanoma, and it is associated with increased development, dissemination, and poor clinical outcomes and prognosis in cancer. Moreover, TOPK phosphorylates p38, JNK, ERK, and AKT, which are involved in many cellular functions, and participates in the activation of multiple signaling pathways related to MAPK, PI3K/PTEN/AKT, and NOTCH1; thus, the direct or indirect interactions of TOPK make it a highly attractive yet elusive target for cancer therapy. Small molecule inhibitors targeting TOPK have shown great therapeutic potential in the treatment of cancer both in vitro and in vivo, even in combination with chemotherapy or radiotherapy. Therefore, targeting TOPK could be an important approach for cancer prevention and therapy. Thus, the purpose of the present review was to consider and analyze the role of TOPK as a drug target in cancer therapy and describe the recent findings related to its role in tumor development. Moreover, this review provides an overview of the current progress in the discovery and development of TOPK inhibitors, considering future clinical applications.

Menin-regulated Pbk controls high fat diet-induced compensatory beta cell proliferation

Pancreatic beta cells undergo compensatory proliferation in the early phase of type 2 diabetes. While pathways such as FoxM1 are involved in regulating compensatory beta cell proliferation, given the lack of therapeutics effectively targeting beta cell proliferation, other targetable pathways need to be identified. Herein, we show that Pbk, a serine/threonine protein kinase, is essential for high fat diet (HFD)‐induced beta cell proliferation in vivo using a Pbk kinase deficiency knock‐in mouse model. Mechanistically, JunD recruits menin and HDAC3 complex to the Pbk promoter to reduce histone H3 acetylation, leading to epigenetic repression of Pbk expression. Moreover, menin inhibitor (MI) disrupts the menin–JunD interaction and augments Pbk transcription. Importantly, MI administration increases beta cell proliferation, ameliorating hyperglycemia, and impaired glucose tolerance (IGT) in HFD‐induced diabetic mice. Notably, Pbk is required for the MI‐induced beta cell proliferation and improvement of IGT. Together, these results demonstrate the repressive role of the menin/JunD/Pbk axis in regulating HFD‐induced compensatory beta cell proliferation and pharmacologically regulating this axis may serve as a novel strategy for type 2 diabetes therapy.

PBK promotes aggressive phenotypes of cervical cancer through ERK/c-Myc signaling pathway

Cervical cancer is the fourth most frequent cancer in women worldwide. PDZ-binding kinase (PBK) is proven to promote the malignant behaviors of various carcinomas. However, its functional roles and oncogenic mechanisms in cervical cancer are poorly understood. In this study, we reported that PBK was highly expressed in cervical cancer tissues. PBK promoted the proliferation, metastasis, and cisplatin resistance of cervical cancer cells. OTS514, a specific PBK inhibitor, could significantly suppress proliferation and metastasis of cervical cancer cells in vitro and in a xenograft model. Besides, OTS514 could enhance cisplatin-based chemosensitivity in cervical cancer cells. Mechanistically, PBK promoted the expression and stabilization of c-Myc through phosphorylating ERK1/2. OTS514 suppressed the phosphorylation of ERK1/2 and the transcriptional activity of c-Myc. Furthermore, inhibition of the ERK signal pathway by U0126 reversed the increased proliferation and metastasis induced by overexpression of PBK. Exogenous expression of c-Myc counteracted the decreased proliferation and metastasis evoked by knockdown of PBK. In conclusion, PBK promoted the malignant progression of cervical cancer through ERK/c-Myc signal pathway. PBK might be a promising molecular target for cervical cancer treatment.

PBK/TOPK: A Therapeutic Target Worthy of Attention

Accumulating evidence supports the role of PDZ-binding kinase (PBK)/T-lymphokine-activated killer-cell-originated protein kinase (TOPK) in mitosis and cell-cycle progression of mitotically active cells, especially proliferative malignant cells. PBK/TOPK was confirmed to be associated with the development, progression, and metastasis of malignancies. Therefore, it is a potential therapeutic target in cancer therapy. Many studies have been conducted to explore the clinical applicability of potent PBK/TOPK inhibitors. However, PBK/TOPK has also been shown to be overexpressed in normal proliferative cells, including sperm and neural precursor cells in the subventricular zone of the adult brain, as well as under pathological conditions, such as ischemic tissues, including the heart, brain, and kidney, and plays important roles in their physiological functions, including proliferation and self-renewal. Thus, more research is warranted to further our understanding of PBK/TOPK inhibitors before we can consider their applicability in clinical practice. In this study, we first review the findings, general features, and signaling mechanisms involved in the regulation of mitosis and cell cycle. We then review the functions of PBK/TOPK in pathological conditions, including tumors and ischemic conditions in the heart, brain, and kidney. Finally, we summarize the advances in potent and selective inhibitors and describe the potential use of PBK/TOPK inhibitors in clinical settings.

PBK/TOPK Inhibitor Suppresses the Progression of Prolactinomas

BACKGROUND

Prolactinoma is the most common type of pituitary tumors, and its resultant tumor occupying and hormone disturbance greatly damage the health of patients. In this study, we investigated a protein kinase-PDZ Binding Kinase (PBK)/T-LAK Cell-Originated Protein Kinase (TOPK) as a candidate protein regulating prolactin (PRL) secretion and tumor growth of prolactinomas.

METHODS

Downloaded prolactinoma transcriptome dataset from Gene Expression Omnibus (GEO) database, and screened differentially expressed genes (DEGs) between normal pituitary tissues and prolactinoma tissues. Then, Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of DEGs were performed, a protein-protein interaction (PPI) network was constructed and the hub genes were identified. After a literature search, TOPK was presumed as an candidate target regulating the prolactinoma. We found a specific inhibitor of TOPK to investigate its effects on the proliferation, migration, apoptosis and PRL secretion of pituitary tumor cells. Finally, the regulation of TOPK inhibitor on its downstream target-p38 Mitogen Activated Protein Kinase (p38 MAPK) was detected to explore the potential mechanism.

RESULTS

A total of 361 DEGs were identified, and 20 hub genes were screened out. TOPK inhibitor HI-TOPK-032 could suppress the proliferation & migration and induce apoptosis of pituitary tumor cells in vitro, and reduce PRL secretion and tumor growth in vivo. HI-TOPK-032 also inhibited the phosphorylation level of the downstream target p38 MAPK, suggesting that TOPK inhibitors regulate the development of prolactinoma by mediating p38 MAPK.

CONCLUSION

Our study of identification and functional validation of TOPK suggests that this candidate can be a promising molecular target for prolactinoma treatment.

Altered immune phenotype and DNA methylation in panic disorder

Background

Multiple studies have related psychiatric disorders and immune alterations. Panic disorder (PD) has been linked with changes in leukocytes distributions in several small studies using different methods for immune characterization. Additionally, alterations in the methylation of repetitive DNA elements, such as LINE-1, have been associated with mental disorders. Here, we use peripheral blood DNA methylation data from two studies and an updated DNA methylation deconvolution library to investigate the relation of leukocyte proportions and methylation status of repetitive elements in 133 patients with panic disorder compared with 118 controls.

Methods and results

We used DNA methylation data to deconvolute leukocyte cell-type proportions and to infer LINE-1 element methylation comparing PD cases and controls. We also identified differentially methylated CpGs associated with PD using an epigenome-wide association study approach (EWAS), with models adjusting for sex, age, and cell-type proportions. Individuals with PD had a lower proportion of CD8T cells (OR: 0.86, 95% CI: 0.78–0.96, P-adj = 0.030) when adjusting for age, sex, and study compared with controls. Also, PD cases had significantly lower LINE-1 repetitive element methylation than controls (P < 0.001). The EWAS identified 61 differentially methylated CpGs (58 hypo- and 3 hypermethylated) in PD (Bonferroni adjusted P < 1.33 × 10^–7).

Conclusions

These results suggest that those with panic disorder have changes to their immune system and dysregulation of repeat elements relative to controls.

Advances in targeted therapy mainly based on signal pathways for nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is a malignant epithelial carcinoma of the head and neck region which mainly distributes in southern China and Southeast Asia and has a crucial association with the Epstein-Barr virus. Based on epidemiological data, both incidence and mortality of NPC have significantly declined in recent decades grounded on the improvement of living standard and medical level in an endemic region, in particular, with the clinical use of individualized chemotherapy and intensity-modulated radiotherapy (IMRT) which profoundly contributes to the cure rate of NPC patients. To tackle the challenges including local recurrence and distant metastasis in the current NPC treatment, we discussed the implication of using targeted therapy against critical molecules in various signal pathways, and how they synergize with chemoradiotherapy in the NPC treatment. Combination treatment including targeted therapy and IMRT or concurrent chemoradiotherapy is presumably to be future options, which may reduce radiation or chemotherapy toxicities and open new avenues for the improvement of the expected functional outcome for patients with advanced NPC.

T-LAK cell-originated protein kinase (TOPK) is a Novel Prognostic and Therapeutic Target in Chordoma

Objectives

To assess the expression, prognostic value, and functionality of T‐lymphokine‐activated killer (T‐LAK) cell‐originated protein kinase (TOPK) in chordoma pathogenesis.

Materials and Methods

TOPK expression in chordoma was assessed via immunohistochemical staining of a tissue microarray (TMA) and correlated with patient clinicopathology. TOPK expression in chordoma cell lines and fresh patient tissues was then evaluated by Western blot. TOPK small interfering RNA (siRNA) and the specific inhibitor OTS514 were applied to determine the roles of TOPK in chordoma pathogenicity. The effect of TOPK expression on chordoma cell clonogenicity was also investigated using clonogenic assays. A 3D cell culture model was utilized to mimic in vivo environment to validate the effect of TOPK inhibition on chordoma cells.

Results

TOPK was highly expressed in 78.2% of the chordoma specimens in the TMA and all chordoma cell lines. High TOPK expression significantly correlated with metastasis, recurrence, disease status and shorter overall survival. Knockdown of TOPK with specific siRNA resulted in significantly decrease chordoma cell viability. Inhibition of TOPK with OTS514 significantly inhibited chordoma cell growth and proliferation, colony‐forming capacity and ex vivo spheroid growth.

Conclusions

High expression of TOPK is an important predictor of poor prognosis in chordoma. Inhibition of TOPK resulted in significantly decrease chordoma cell proliferation and increase apoptosis. Our results indicate TOPK as a novel prognostic biomarker and therapeutic target for chordoma.

Multi-Omics Characterization of the 4T1 Murine Mammary Gland Tumor Model

Background: Tumor models are critical for our understanding of cancer and the development of cancer therapeutics. The 4T1 murine mammary cancer cell line is one of the most widely used breast cancer models. Here, we present an integrated map of the genome, transcriptome, and immunome of 4T1.

Results: We found Trp53 (Tp53) and Pik3g to be mutated. Other frequently mutated genes in breast cancer, including Brca1 and Brca2, are not mutated. For cancer related genes, Nav3, Cenpf, Muc5Ac, Mpp7, Gas1, MageD2, Dusp1, Ros, Polr2a, Rragd, Ros1, and Hoxa9 are mutated. Markers for cell proliferation like Top2a, Birc5, and Mki67 are highly expressed, so are markers for metastasis like Msln, Ect2, and Plk1, which are known to be overexpressed in triple-negative breast cancer (TNBC). TNBC markers are, compared to a mammary gland control sample, lower (Esr1), comparably low (Erbb2), or not expressed at all (Pgr). We also found testis cancer antigen Pbk as well as colon/gastrointestinal cancer antigens Gpa33 and Epcam to be highly expressed. Major histocompatibility complex (MHC) class I is expressed, while MHC class II is not. We identified 505 single nucleotide variations (SNVs) and 20 insertions and deletions (indels). Neoantigens derived from 22 SNVs and one deletion elicited CD8⁺ or CD4⁺ T cell responses in IFNγ-ELISpot assays. Twelve high-confidence fusion genes were observed. We did not observe significant downregulation of mismatch repair (MMR) genes or SNVs/indels impairing their function, providing evidence for 6-thioguanine resistance. Effects of the integration of the murine mammary tumor virus were observed at the genome and transcriptome level.

Conclusions: 4T1 cells share substantial molecular features with human TNBC. As 4T1 is a common model for metastatic tumors, our data supports the rational design of mode-of-action studies for pre-clinical evaluation of targeted immunotherapies.

Autophagy plays a positive role in induction of epidermal proliferation

Autophagy is a multistage catabolic process that mediates stress responses. However, the role of autophagy in epidermal proliferation, particularly under conditions when the epidermis becomes "activated" (hyperproliferative), remains unclear. We have shown that inhibition of Beclin 1, a key activator in the initiation phase of autophagy, attenuates imiquimod (IMQ)-induced epidermal hyperplasia in adult mice as well as naturally occurring hyperproliferation in neonatal mouse epidermis. Inhibition of Beclin 1 did not change the levels of several key inflammatory molecules or the numbers of immune cells in lesional skins. This indicates that autophagy does not affect inflammatory regulators in IMQ-treated mouse skin. Bioinformatic analysis combined with gene expression quantitative assays, revealed that a deficiency in autophagy decreases the expression of PDZ Binding Kinase (PBK), a regulator of the cell cycle, in mouse epidermis and human epidermal keratinocytes (HEKs). Interestingly, the decrease in PBK results in inhibition of proliferation in HEKs and such reduced proliferation can be rescued by activation of p38, the downstream signaling of PBK. Collectively, autophagy plays a positive role in epidermal proliferation, which is in part via regulating PBK expression.

Suppression of p38-MAPK endows endoderm propensity to human embryonic stem cells

The ability of human embryonic stem cells (hESCs) to proliferate unlimitedly and give rise to all tissues makes these cells a promising source for cell replacement therapies. To realize the full potential of hESCs in cell therapy, it is necessary to interrogate regulatory pathways that influence hESC maintenance and commitment. Here, we reveal that pharmacological attenuation of p38 mitogen-activated protein kinase (p38-MAPK) in hESCs concomitantly augments some characteristics associated with pluripotency and the expressions of early lineage markers. Moreover, this blockage capacitates hESCs to differentiate towards an endoderm lineage at the expense of other lineages upon spontaneous hESC differentiation. Notably, hESCs pre-treated with p38-MAPK inhibitor exhibit significantly improved pancreatic progenitor directed differentiation. Together, our findings suggest a new approach to the robust endoderm differentiation of hESCs and potentially enables the facile derivation of various endoderm-derived lineages such as pancreatic cells.

A novel loss-of-function mutation of PBK associated with human kidney stone disease

Kidney stone disease (KSD) is a prevalent disorder that causes human morbidity worldwide. The etiology of KSD is heterogeneous, ranging from monogenic defect to complex interaction between genetic and environmental factors. Since mutations of genes responsible for KSD in a majority of families are still unknown, our group is identifying mutations of these genes by means of genomic and genetic analyses. In this study, we identified a novel loss-of-function mutation of PBK, encoding the PDZ binding kinase, that was found to be associated with KSD in an affected Thai family. Glycine (Gly) substituted by arginine (Arg) at position 43 (p.Gly43Arg) in PBK cosegregated with the disease in affected members of this family, but was absent in 180 normal control subjects from the same local population. Gly43 is highly evolutionarily conserved in vertebrates, and its substitution affects protein structure by alterations in H-bond forming patterns. This p.Gly43Arg substitution results in instability of the variant PBK protein as examined in HEK293T cells. The variant PBK protein (p.Gly43Arg) demonstrated decreased kinase activity to phosphorylate p38 MAPK as analyzed by immunoblotting and antibody microarray techniques. Taken together, these findings suggest a possible new mechanism of KSD associated with pathogenic PBK variation.

Liposomal OTS964, a TOPK inhibitor: a simple method to estimate OTS964 association with liposomes that relies on enhanced OTS964 fluorescence when bound to albumin

OTS964 is an inhibitor of T-lymphokine-activated killer cell-originated protein kinase (TOPK), a protein kinase important for mitosis and highly expressed in ovarian and lung cancers. This compound demonstrated potent anti-proliferative activity in a panel of cell lines positive for TOPK; however, when administered to mouse xenograft models, adverse hematopoietic toxicities were observed. To overcome this problem, OTS964 was encapsulated into liposomes and a liposomal formulation of OTS964 is now considered a lead candidate for clinical development. To support clinical development of this formulation, it is critically important to define assays that can easily distinguish between free and liposomal OTS964. Here, we develop a new assay to determine liposomal OTS964 encapsulation (percentage of drug associated with the liposomes) and OTS964 that is dissociated from the liposomes (percentage of drug released from liposomes) by monitoring the enhanced OTS964 fluorescence after its binding to albumin. The optical properties of OTS964 were investigated and three absorbance peaks were identified (235 nm, 291 nm, and 352 nm). Fluorescence was observed at 350 nm (excitation) and 470 nm (emission). Interestingly, the fluorescence of OTS964 increased 18-fold in the presence of serum proteins and more specifically albumin. This phenomenon was used to discriminate between the amounts of drug associated with the liposomes or released from the liposomes. Controls consisting of liposomal OTS964 permeabilized with saponins or octyl glucopyranoside served to confirm that drug release could be monitored by albumin-associated increases in fluorescence. The OTS964 liposomal formulation proved to be very stable with less than 10% release after 4 days in phosphate-buffered saline at 37 °C. The quantity of drug associated with the liposomal surface but not inside the liposomes could also be estimated using this approach. These studies present a novel approach to characterize liposomal release of OTS964, in real time and in a non-invasive manner while acquiring additional information about the spatial distribution of liposomal drug.

Gossypetin Inhibits Solar-UV Induced Cutaneous Basal Cell Carcinoma Through Direct Inhibiting PBK/TOPK Protein Kinase

BACKGROUND

Skin photoaging, skin inflammation and skin cancer are related with excessive exposure to solar UV. PDZ-binding kinase/T-LAK cell-originated protein kinase (PBK/TOPK), a member of the serine/threonine protein kinase, which regulates the signaling cascades of p38 mitogen-activated protein kinase (p38 MAPK) and extracellular signal regulated kinase 1/2 (ERK1/2). PBK/TOPK plays a significant role in solar-UV-induced cutaneous basal cell carcinoma (BCC), and targeting PBK/TOPK can be supposed to treat and prevent cutaneous BCC.

METHODS

The pathological feature and the expression level of PBK/TOPK in cutaneous BCC tissues of human were studied in clinical samples. SUV-induced the phosphorylation of p38 MAPK and ERK1/2 were demonstrated ex vivo. Moreover, the interaction between Gossypetin and PBK/TOPK were detected by in vitro kinase assay and Microscale thermophoresis (MST) assay. Furthermore, the effect of Gossypetin to solar UV-induced the activity of PBK/TOPK were detected ex vivo and in vivo.

RESULTS

The clinical samples showed that the expression levels of PBK/TOPK, phosphor-p38 MAPK and phosphor- ERK1/2 were up-regulated in cutaneous BCC tissues of human. The expression of phosphor-p38 MAPK or phosphor-ERK1/2 increased in a dose and time dependent manner after solar UV treatment in HaCaT cells. MTT cytotoxicity assay results showed that Gossypetin has no effect on HaCaT cells. In vitro kinase assay and MST assay results showed that Gossypetin bound with PBK/TOPK and suppressed PBK/TOPK activity. Ex vivo results showed Gossypetin inhibited solar UV-induced phosphorylation of PBK/TOPK, p38 MAPK, ERK1/2 and H2AX by suppressing PBK/TOPK activity. In vivo test results indicated that Gossypetin suppressed solar UV-induced increase of PBK/TOPK, phosphor-p38 MAPK, phosphor-ERK1/2 and phosphor- H2AX in SKH-1 hairless mice.

CONCLUSION

Our data demonstrated that Gossypetin can alleviate solar-UV-induced cutaneous BCC by blocking PBK/TOPK, and Gossypetin could be a remarkable agent for treating solar-UV induced cutaneous basal cell carcinoma.

TOPK promotes metastasis of esophageal squamous cell carcinoma by activating the Src/GSK3β/STAT3 signaling pathway via γ-catenin

Background

Esophageal squamous cell carcinoma (ESCC) is a fatal disease with poor prognosis. The predominant reason for ESCC-related death is distal metastasis. A comprehensive understanding of the molecular mechanism underlying metastasis is needed for improving patient prognosis. T-LAK cell-originated protein kinase (TOPK) is a MAPKK-like kinase, which plays a vital role in various physiological and pathophysiological processes. However, the role of TOPK in ESCC metastasis is unclear.

Methods

Tissue array was used to evaluate the correlation between TOPK expression and ESCC lymph node metastasis. Wound healing assay, transwell assay, and lung metastasis mice model were used to examine the role of TOPK in the migration of ESCC cells in vitro and in vivo. Protein kinase array, mass spectrometry (MS), and molecular modeling were used to examine the pathways and direct target proteins of TOPK that are involved in ESCC metastasis. Additionally, immunofluorescence and western blotting analyses were performed to verify these findings.

Results

The enhanced expression of TOPK was correlated with lymph node metastasis in the ESCC tissues. TOPK knockdown or treatment with the TOPK inhibitor (HI-TOPK-032) decreased the invasion and migration of ESCC cells in vitro. HI-TOPK-032 also inhibited the lung metastasis in ESCC cell xenograft in vivo model. Moreover, TOPK promoted the invasion of ESCC cells by activating the Src/GSK3β/STAT3 and ERK signaling pathways via γ-catenin.

Conclusion

The findings of this study reveal that TOPK is involved in ESCC metastasis and promoted the ESCC cell mobility by activating the Src/GSK3β/STAT3 and ERK signaling pathways. This indicated that TOPK may be a potential molecular therapeutic target for ESCC metastasis.

Potent anti-myeloma activity of the TOPK inhibitor OTS514 in pre-clinical models

Multiple myeloma (MM) continues to be considered incurable, necessitating new drug discovery. The mitotic kinase T‐LAK cell‐originated protein kinase/PDZ‐binding kinase (TOPK/PBK) is associated with proliferation of tumor cells, maintenance of cancer stem cells, and poor patient prognosis in many cancers. In this report, we demonstrate potent anti‐myeloma effects of the TOPK inhibitor OTS514 for the first time. OTS514 induces cell cycle arrest and apoptosis at nanomolar concentrations in a series of human myeloma cell lines (HMCL) and prevents outgrowth of a putative CD138⁺ stem cell population from MM patient‐derived peripheral blood mononuclear cells. In bone marrow cells from MM patients, OTS514 treatment exhibited preferential killing of the malignant CD138⁺ plasma cells compared with the CD138⁻ compartment. In an aggressive mouse xenograft model, OTS964 given orally at 100 mg/kg 5 days per week was well tolerated and reduced tumor size by 48%‐81% compared to control depending on the initial graft size. FOXO3 and its transcriptional targets CDKN1A (p21) and CDKN1B (p27) were elevated and apoptosis was induced with OTS514 treatment of HMCLs. TOPK inhibition also induced loss of FOXM1 and disrupted AKT, p38 MAPK, and NF‐κB signaling. The effects of OTS514 were independent of p53 mutation or deletion status. Combination treatment of HMCLs with OTS514 and lenalidomide produced synergistic effects, providing a rationale for the evaluation of TOPK inhibition in existing myeloma treatment regimens.

Targeting PDZ-binding kinase is anti-tumorigenic in novel preclinical models of ACC

Adrenocortical carcinoma (ACC) is an aggressive orphan malignancy with less than 35% 5-year survival and 75% recurrence. Surgery remains the primary therapy and mitotane, an adrenolytic, is the only FDA-approved drug with wide-range toxicities and poor tolerability. There are no targeted agents available to date. For the last three decades, H295R cell line and its xenograft were the only available preclinical models. We recently developed two new ACC patient-derived xenograft mouse models and corresponding cell lines (CU-ACC1 and CU-ACC2) to advance research in the field. Here, we have utilized these novel models along with H295R cells to establish the mitotic PDZ-binding kinase (PBK) as a promising therapeutic target. PBK is overexpressed in ACC samples and correlates with poor survival. We show that PBK is regulated by FOXM1 and targeting PBK via shRNA decreased cell proliferation, clonogenicity and anchorage-independent growth in ACC cell lines. PBK silencing inhibited pAkt, pp38MAPK and pHistone H3 altering the cell cycle. Therapeutically, targeting PBK with the small-molecule inhibitor HITOPK032 phenocopied PBK-specific modulation of pAkt and pHistone H3, but also induced apoptosis via activation of JNK. Consistent with in vitro findings, treatment of CU-ACC1 PDXs with HITOPK032 significantly reduced tumor growth by 5-fold (P < 0.01). Treated tumor tissues demonstrated increased rates of apoptosis and JNK activation, with decreased pAkt and Histone H3 phosphorylation, consistent with effects observed in ACC cell lines. Together these studies elucidate the mechanism of PBK in ACC tumorigenesis and establish the potential therapeutic potential of HITOPK032 in ACC patients.

Off-target toxicity is a common mechanism of action of cancer drugs undergoing clinical trials

Ninety-seven percent of drug-indication pairs that are tested in clinical trials in oncology never advance to receive U.S. Food and Drug Administration approval. While lack of efficacy and dose-limiting toxicities are the most common causes of trial failure, the reason(s) why so many new drugs encounter these problems is not well understood. Using CRISPR-Cas9 mutagenesis, we investigated a set of cancer drugs and drug targets in various stages of clinical testing. We show that-contrary to previous reports obtained predominantly with RNA interference and small-molecule inhibitors-the proteins ostensibly targeted by these drugs are nonessential for cancer cell proliferation. Moreover, the efficacy of each drug that we tested was unaffected by the loss of its putative target, indicating that these compounds kill cells via off-target effects. By applying a genetic target-deconvolution strategy, we found that the mischaracterized anticancer agent OTS964 is actually a potent inhibitor of the cyclin-dependent kinase CDK11 and that multiple cancer types are addicted to CDK11 expression. We suggest that stringent genetic validation of the mechanism of action of cancer drugs in the preclinical setting may decrease the number of therapies tested in human patients that fail to provide any clinical benefit.

Secondary analysis of existing microarray data reveals potential gene drivers of cutaneous squamous cell carcinoma

Cutaneous squamous-cell carcinoma (cSCC) is the second most common skin cancer, with an increasing incidence in recent years. To define the molecular basis that drive cSCC development and progression, this study aimed at identifying potential novel molecular targets for the diagnosis and therapy of patients with cSCC. Two data sets with the accession number GSE45164 and GSE66359 were downloaded from Gene Expression Omnibus (GEO) database. After the identification of differentially expressed genes (DEGs) from these two data sets, respectively, between cSCC samples and controls, a combination of DEGs from these two data sets were subjected to the following analyses, including functional annotation, protein-protein interaction (PPI) network and module construction, transcription factor (TF)-target regulation prediction, and drug-gene interaction predictive analysis. A total of 204 upregulated genes and 213 downregulated genes were found in two data sets which were used for the follow-up analysis. Upregulated and downregulated genes were mainly involved in the functions such as cell division, mitotic nuclear division, cell cycle, and p53 signaling pathway. Interferon induced protein family members and proteasome subunit members were involved in the TF-target regulatory network, such as PSMB8, CXCL10, and IFIT3. Eight upregulated genes ( TOP2A, CXCL8, RRM2, PSMB8, PSMB9, PBK, CXCL10, and ISG15) that were hub genes in the PPI network and significant modules were identified in the predicted drug-gene interaction. In conclusion, TOP2A, CXCL8, RRM2, PSMB8, PSMB9, PBK, CXCL10, and ISG15 may be potential targets for the diagnosis and therapy of patients with cSCC.

Kinome expression profiling to target new therapeutic avenues in multiple myeloma

Multiple myeloma (MM) account for approximately 10% of hematological malignancies and is the second most common hematological disorder. Kinases inhibitors are widely used and their efficiency for the treatment of cancers has been demonstrated. Here, in order to identify kinases of potential therapeutic interest for the treatment of MM, we investigated the prognostic impact of the kinome expression profile in large cohorts of patients. We identified 36 kinome-related genes significantly linked with a prognostic value to MM, and built a kinome index based on their expression. The Kinome Index (KI) is linked to prognosis, proliferation, differentiation, and relapse in MM. We then tested inhibitors targeting seven of the identified protein kinas-es (PBK, SRPK1, CDC7-DBF4, MELK, CHK1, PLK4, MPS1/TTK) in human myeloma cell lines. All tested inhibitors significantly reduced the viability of myeloma cell lines, and we confirmed the potential clinical interest of three of them on primary myeloma cells from patients. In addition, we demonstrated their ability to potentialize the toxicity of conventional treatments, including Melphalan and Lenalidomide. This highlights their potential beneficial effect in myeloma therapy. Three kinases inhibitors (CHK1i, MELKi and PBKi) overcome resistance to Lenalidomide, while CHK1, PBK and DBF4 inhibitors re-sensitize Melphalan resistant cell line to this conventional therapeutic agent. Altogether, we demonstrate that kinase inhibitors could be of therapeutic interest especially in high-risk myeloma patients defined by the KI. CHEK1, MELK, PLK4, SRPK1, CDC7-DBF4, MPS1/TTK and PBK inhibitors could represent new treatment options either alone or in combination with Melphalan or IMiD for refractory/relapsing myeloma patients.

Dual FLT3 inhibitors: Against the drug resistance of acute myeloid leukemia in recent decade

Acute myeloid leukemia (AML) is a malignant disease characterized by abnormal growth and differentiation of hematopoietic stem cells. Although the pathogenesis has not been fully elucidated, many specific gene mutations have been found in AML. Fms-like tyrosine kinase 3 (FLT3) is recognized as a drug target for the treatment of AML, and the activation mutations of FLT3 were found in about 30% of AML patients. Targeted inhibition of FLT3 receptor tyrosine kinase has shown promising results in the treatment of FLT3 mutation AML. Unfortunately, the therapeutic effects of FLT3 tyrosine kinase inhibitors used as AML monotherapy are usually accompanied by the high risk of resistance development within a few months after treatment. FLT3 dual inhibitors were generated with the co-inhibition of FLT3 and another target, such as CDK4, JAK2, MEK, Mer, Pim, etc., to solve the problems mentioned above. As a result, the therapeutic effect of the drug is significantly improved, while the toxic and side effects are reduced. Besides, the life quality of AML patients with FLT3 mutation has been effectively improved. In this paper, we reviewed the studies of dual FLT3 inhibitors that have been discovered in recent years for the treatment of AML.

Baicalin suppresses lung cancer growth by targeting PDZ-binding kinase/T-LAK cell-originated protein kinase

Baicalin is the main bioactive component extracted from the traditional Chinese medicine Baical Skullcap Root, and its anti-tumor activity has been studied in previous studies. PDZ-binding kinase/T-LAK cell-originated protein kinase (PBK/TOPK), a serine/threonine protein kinase, is highly expressed in many cancer cells and stimulates the tumorigenic properties, and so, it is a pivotal target for agent to cure cancers. We reported for the first time that baicalin suppressed PBK/TOPK activities by directly binding with PBK/TOPK in vitro and in vivo. Ex vivo studies showed that baicalin suppressed PBK/TOPK activity in JB6 Cl41 cells and H441 lung cancer cells. Moreover, knockdown of PBK/TOPK in H441 cells decreased their sensitivity to baicalin. In vivo study indicated that injection of baicalin in H441 tumor-bearing mice effectively suppressed cancer growth. The PBK/TOPK downstream signaling molecules Histone H3 and ERK2 in tumor tissues were also decreased after baicalin treatment. Taken together, baicalin can inhibit proliferation of lung cancer cells as a PBK/TOPK inhibitor both in vitro and in vivo.

PBK overexpression promotes metastasis of hepatocellular carcinoma via activating ETV4-uPAR signaling pathway

Invasion and metastasis are the predominant causes of lethal outcomes in patients with hepatocellular carcinoma (HCC). However, the molecular mechanism underlying the invasive or metastatic process are still insufficiently understood. Here, we first integrated several public databases and identified a novel protein kinase, PDZ-binding kinase (PBK) that was frequently upregulated and correlated with poor prognosis in patients with HCC. Gain- or loss-of-function analysis revealed that PBK promoted migration and invasion of HCC cells both in vitro and in vivo. Mechanistically, PBK enhanced uPAR expression by activating its promoter activity. Chromatin immunoprecipitation (ChIP) assay showed that ETV4 directly bound to the core region of uPAR promoter while PBK could enhance the binding of ETV4 to uPAR promoter. In orthotopic mouse model, PBK knockdown markedly inhibited the lung metastasis of HCC cells, while this effect was significantly restored by uPAR overexpression. Finally, there was a positive correlation between PBK and uPAR, ETV4 and uPAR in HCC clinical samples. Collectively, these findings revealed that PBK acted as a crucial kinase by promoting invasion and migration via the ETV4-uPAR signaling pathway, and it therefore could be a promising diagnostic biomarker and therapeutic target for HCC metastasis.

PBK/TOPK overexpression and survival in solid tumors: A PRISMA-compliant meta-analysis

BACKGROUND

The prognostic significance of PBK/TOPK overexpression in solid tumors remains controversial. Therefore, we carried out a meta-analysis to evaluate the impact of PBK/TOPK overexpression in solid tumors on patients' overall survival (OS) and disease-free survival (DFS).

METHODS

Relevant articles were identified through searching the PubMed, Embase and Web of Science up to May 2017. The pooled hazard ratio (HR) with 95% confidence interval (CI) was used to estimate the effects.

RESULTS

In this meta-analysis, 12 studies involving 1571 participants were included, PBK/TOPK overexpression was significantly associated with poor OS (pooled HR = 1.91, 95%CI = 1.22-3.00, P = .005) and short DFS (pooled HR = 1.95, 95%CI = 1.46-2.58, P < .001).

CONCLUSIONS

PBK/TOPK overexpression was associated with poor survival in human solid tumors which may be a valuable prognosis biomarker and a potential therapeutic target of solid tumors.

Diagnostic and Prognostic Biomarkers of Adrenal Cortical Carcinoma

The diagnosis of low-grade adrenal cortical carcinoma (ACC) confined to the adrenal gland can be challenging. Although there are diagnostic and prognostic molecular tests for ACC, they remain largely unutilized. We examined the diagnostic and prognostic value of altered reticulin framework and the immunoprofile of biomarkers including IGF-2, proteins involved in cell proliferation and mitotic spindle regulation (Ki67, p53, BUB1B, HURP, NEK2), DNA damage repair (PBK, γ-H2AX), telomere regulation (DAX, ATRX), wnt-signaling pathway (beta-catenin) and PI3K signaling pathway (PTEN, phospho-mTOR) in a tissue microarray of 50 adenomas and 43 carcinomas that were characterized for angioinvasion as defined by strict criteria, Weiss score, and mitotic rate-based tumor grade. IGF-2 and proteins involved in cell proliferation and mitotic spindle regulation (Ki67, p53, BUB1B, HURP, NEK2), DNA damage proteins (PBK, γ-H2AX), regulators of telomeres (DAXX, ATRX), and beta-catenin revealed characteristic expression profiles enabling the distinction of carcinomas from adenomas. Not all biomarkers were informative in all carcinomas. IGF-2 was the most useful biomarker of malignancy irrespective of tumor grade and cytomorphologic features, as juxtanuclear Golgi-pattern IGF-2 reactivity optimized for high specificity was identified in up to 80% of carcinomas and in no adenomas. Loss rather than qualitative alterations of the reticulin framework yielded statistical difference between carcinoma and adenoma. Angioinvasion defined as tumor cells invading through a vessel wall and intravascular tumor cells admixed with thrombus proved to be the best prognostic parameter, predicting adverse outcome in the entire cohort as well as within low-grade ACCs. Low mitotic tumor grade, Weiss score, global loss of DAXX expression, and high phospho-mTOR expression correlated with disease-free survival, but Weiss score and biomarkers failed to predict adverse outcome in low-grade disease. Our results underscore the importance of careful morphologic assessment coupled with ancillary diagnostic and prognostic biomarkers of ACC.

LincK contributes to breast tumorigenesis by promoting proliferation and epithelial-to-mesenchymal transition

BACKGROUND

Increasing evidence has demonstrated that mesenchymal stem cells (MSCs) play a role in the construction of tumor microenvironments. Co-culture between tumor cells and MSCs provides an easy and useful platform for mimicking tumor microenvironments and identifying the important members involved in tumor progress. The long non-coding RNAs (lncRNAs) have been shown to regulate different tumorigenic processes. In this study, we aimed to examine functional lncRNA deregulations associated with breast cancer malignancy instigated by MSC-MCF-7 co-culture.

METHODS

The microarrays were used to profile the expression changes of lncRNAs in MCF-7 cells during epithelial-mesenchymal transition (EMT) induced by co-culture with MSCs. We found that an intergenic lncRNA KB-1732A1.1 (termed LincK, partly overlapped with GASL1) was significantly elevated. To investigate the biological function of LincK, the expression of EMT markers, cell migration, invasion, proliferation, and colony formation were evaluated in vitro and xenograft assay in nude mice were performed in vivo. Furthermore, we detected LincK expression in clinical samples using RNAscope® technology and verified aberrant expression of LincK in breast cancer data sets from The Cancer Genome Atlas (TCGA) by bioinformatic analysis. The underlying mechanisms of LincK were investigated using mRNA microarray analyses, Western blot, RNA pull down, and RNA immunoprecipitation.

RESULTS

LincK induced an EMT progress in breast cancer cells (BCC) MCF-7, MDA-MB-453, and MDA-MB-231. The depletion of LincK decreased the growth, migration, and invasion in BCC, whereas the overexpression of LincK exerted the opposite effects. Moreover, knockdown of LincK repressed tumorigenesis, and ectopic expression of LincK promoted tumor growth in MCF-7 xenograft model. LincK ablation in MDA-MB-231 cells dramatically impaired lung metastasis when incubated intravenously into nude mice. Further, LincK was frequently elevated in breast cancer compared with normal breast tissue in clinical samples. Mechanistically, LincK may share common miRNA response elements with PBK and ZEB1 and regulate the effects of miR-200 s.

CONCLUSION

LincK plays a significant role in regulating EMT and tumor growth and could be a potential therapeutic target in breast cancer.

PBK, targeted by EVI1, promotes metastasis and confers cisplatin resistance through inducing autophagy in high-grade serous ovarian carcinoma

High-grade serous ovarian carcinoma (HGSOC) is the most lethal type of gynecologic malignancy. Chemoresistance is the main reason for the poor prognosis of HGSOC. PDZ-binding kinase (PBK) promotes the malignant progression of various carcinomas. However, the roles and clinical significance of PBK in HGSOC remain unclear. Here, we reported that PBK was overexpressed in HGSOC tissues and cell lines. High PBK expression was associated with a poor prognosis, metastasis, and cisplatin resistance of HGSOC. Overexpression of PBK promoted autophagy and enhanced cisplatin resistance via the ERK/mTOR signaling pathway. Further study showed that inhibition of autophagy by chloroquine or bafilomycin A1 reversed PBK-induced cisplatin resistance. Overexpression of PBK decreased ovarian cancer responsiveness to cisplatin treatment through inducing autophagy in vivo. We also demonstrated that the PBK inhibitor OTS514 augmented the growth inhibition effect of cisplatin in vitro and in vivo. Moreover, ecotropic viral integration site-1 (EVI1) could regulate PBK expression through directly targeting the PBK promoter region. In conclusion, high PBK expression was correlated with a poor prognosis, metastasis, and cisplatin resistance through promoting autophagy in HGSOC. PBK might be a promising target for the early diagnosis and individual treatment of ovarian cancer.

A reciprocal feedback between the PDZ binding kinase and androgen receptor drives prostate cancer

Elucidation of mechanisms underlying the increased androgen receptor (AR) activity and subsequent development of aggressive prostate cancer (PrCa) is pivotal in developing new therapies. Using a systems biology approach, we interrogated the AR-regulated proteome and identified PDZ binding kinase (PBK) as a novel AR-regulated protein that regulates full-length AR and AR variants (ARVs) activity in PrCa. PBK overexpression in aggressive PrCa is associated with early biochemical relapse and poor clinical outcome. In addition to its carboxy terminus ligand-binding domain, PBK directly interacts with the amino terminus transactivation domain of the AR to stabilise it thereby leading to increased AR protein expression observed in PrCa. Transcriptome sequencing revealed that PBK is a mediator of global AR signalling with key roles in regulating tumour invasion and metastasis. PBK inhibition decreased growth of PrCa cell lines and clinical specimen cultured ex vivo. We uncovered a novel interplay between AR and PBK that results in increased AR and ARVs expression that executes AR-mediated growth and progression of PrCa, with implications for the development of PBK inhibitors for the treatment of aggressive PrCa.

Prognostic Value of PDZ-Binding Kinase/T-LAK Cell-Originated Protein Kinase (PBK/TOPK) in Patients with Cancer

Background: PDZ-binding kinase/T-LAK cell-originated protein kinase (PBK/TOPK) plays a critical role in tumorigenesis and cancer progression. However, the prognostic roles in cancer patients are inconsistent or even controversial. Therefore, we performed a meta-analysis to investigate the prognostic value of PBK/TOPK in cancers.

Methods: Literature search was performed using several online databases (PubMed, Web of Science, Embase, Cochrane Library, and Google Scholar, National Knowledge Infrastructure and Wanfang) for eligible articles published up to May 1, 2018. The relationship between PBK/TOPK expression and prognosis in cancers was investigated by using pooled hazard ratios (HRs) with 95% confidence intervals (CIs) through STATA 12.0 software.

Results: Totally 20 eligible studies were included in this meta-analysis. The pooled results showed that carriers with high protein expression of PBK/TOPK were significantly associated with poor OS (HR: 1.69, 95% CI: 1.33-2.04) in various cancers, and patients with increased PBK/TOPK protein expression were significantly correlated with inferior RFS (HR: 1.63, 95% CI: 1.02-2.24) and short DFS (HR: 1.69, 95% CI: 1.16-2.23).

Conclusions: The findings suggest that PBK/TOPK protein expression might serve as a prognostic tumor marker in cancers.

Novel selective TOPK inhibitor SKLB-C05 inhibits colorectal carcinoma growth and metastasis

The mitogen-activated protein kinase (MAPK) signaling pathway member T-LAK cell-originated protein kinase/PDZ-binding kinase (TOPK/PBK) is closely involved in tumorigenesis and progression. Its overexpression in colorectal carcinoma (CRC) exacerbates tumor malignancy, promotes metastasis and results in dismal prognosis. Therefore, targeting TOPK is a promising approach for CRC therapy. Here, we report the development of a TOPK selective inhibitor SKLB-C05, with subnanomolar inhibitory potency. In vitro, SKLB-C05 exhibited excellent cytotoxicity and anti-migration and invasion activity on TOPK high-expressing CRC cells and induced cell apoptosis. These activities could attribute to its inhibition of TOPK downstream signaling including extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and c-Jun N-terminal kinase 1, 2, and 3 (JNK1/2/3), as well as downregulation of FAK/Src- MMP signaling. Furthermore, SKLB-C05 disrupted cell mitosis and blocked CRC cell cycle. In vivo, oral administration of SKLB-C05 at concentrations of 20 and 10 mg kg^-1·day^-1 dramatically attenuated CRC tumor xenograft growth and completely suppressed hepatic metastasis of HCT116 cells, respectively. Thus, these findings suggest that SKLB-C05 is a specific TOPK inhibitor with potent anti-CRC oncogenic activity in vitro and in vivo.

Current Challenges and Opportunities in Treating Glioblastoma

Glioblastoma multiforme (GBM), the most common and aggressive primary brain tumor, has a high mortality rate despite extensive efforts to develop new treatments. GBM exhibits both intra- and intertumor heterogeneity, lending to resistance and eventual tumor recurrence. Large-scale genomic and proteomic analysis of GBM tumors has uncovered potential drug targets. Effective and “druggable” targets must be validated to embark on a robust medicinal chemistry campaign culminating in the discovery of clinical candidates. Here, we review recent developments in GBM drug discovery and delivery. To identify GBM drug targets, we performed extensive bioinformatics analysis using data from The Cancer Genome Atlas project. We discovered 20 genes, BOC, CLEC4GP1, ELOVL6, EREG, ESR2, FDCSP, FURIN, FUT8-AS1, GZMB, IRX3, LITAF, NDEL1, NKX3-1, PODNL1, PTPRN, QSOX1, SEMA4F, TH, VEGFC, and C20orf166AS1 that are overexpressed in a subpopulation of GBM patients and correlate with poor survival outcomes. Importantly, nine of these genes exhibit higher expression in GBM versus low-grade glioma and may be involved in disease progression. In this review, we discuss these proteins in the context of GBM disease progression. We also conducted computational multi-parameter optimization to assess the blood-brain barrier (BBB) permeability of small molecules in clinical trials for GBM treatment. Drug delivery in the context of GBM is particularly challenging because the BBB hinders small molecule transport. Therefore, we discuss novel drug delivery methods, including nanoparticles and prodrugs. Given the aggressive nature of GBM and the complexity of targeting the central nervous system, effective treatment options are a major unmet medical need. Identification and validation of biomarkers and drug targets associated with GBM disease progression present an exciting opportunity to improve treatment of this devastating disease.

Design, synthesis and biological evaluation of novel 1-phenyl phenanthridin-6(5H)-one derivatives as anti-tumor agents targeting TOPK

T-lymphokine-activated killer cell-originated protein kinase (TOPK) is a serine-threonine mitogen-activated protein kinase that is highly expressed in many types of human cancer. Due to its important role in cancer progression, TOPK is becoming an attractive target in chemotherapeutic drug design. In this study, a series of 1-phenyl phenanthridin-6(5H)-one derivatives have been identified as a novel chemical class of TOPK inhibitors. Some of them displayed very potent anti-cancer activity with IC₅₀s less than 100 nM, superior than reference compound OTS964. The most potent compound, 9g suppressed the growth of cancer cells by apoptosis and specifically inhibited the activities of TOPK. Oral administration of 9g effectively suppressed tumor growth with TGI >79.7% in colorectal cancer xenograft models, demonstrating superior efficacy compared to OTS964. Pharmacokinetic studies reveal its good oral bioavailability. Our findings therefore show that 9g is a specific inhibitor of TOPK both in vitro and in vivo that may be further developed as a potential therapeutic agent against colorectal cancer.

T-LAK cell-originated protein kinase (TOPK): an emerging target for cancer-specific therapeutics

'Targeted' or 'biological' cancer treatments rely on differential gene expression between normal tissue and cancer, and genetic changes that render tumour cells especially sensitive to the agent being applied. Problems exist with the application of many agents as a result of damage to local tissues, tumour evolution and treatment resistance, or through systemic toxicity. Hence, there is a therapeutic need to uncover specific clinical targets which enhance the efficacy of cancer treatment whilst minimising the risk to healthy tissues. T-LAK cell-originated protein kinase (TOPK) is a MAPKK-like kinase which plays a role in cell cycle regulation and mitotic progression. As a consequence, TOPK expression is minimal in differentiated cells, although its overexpression is a pathophysiological feature of many tumours. Hence, TOPK has garnered interest as a cancer-specific biomarker and biochemical target with the potential to enhance cancer therapy whilst causing minimal harm to normal tissues. Small molecule inhibitors of TOPK have produced encouraging results as a stand-alone treatment in vitro and in vivo, and are expected to advance into clinical trials in the near future. In this review, we present the current literature pertaining to TOPK as a potential clinical target and describe the progress made in uncovering its role in tumour development. Firstly, we describe the functional role of TOPK as a pro-oncogenic kinase, followed by a discussion of its potential as a target for the treatment of cancers with high-TOPK expression. Next, we provide an overview of the current preclinical progress in TOPK inhibitor discovery and development, with respect to future adaptation for clinical use.

Cytoplasmic, nuclear, and total PBK/TOPK expression is associated with prognosis in colorectal cancer patients: A retrospective analysis based on immunohistochemistry stain of tissue microarrays

Objective

PDZ-binding kinase/T-LAK cell-originated protein kinase (PBK/TOPK) regulates components of the cell cycle, including cell growth, immune responses, DNA damage repair, apoptosis, and inflammation. PBK/TOPK may also accelerate tumorigenesis in colorectal cancer.

Methods

We investigated the impact of PBK/TOPK on the clinical outcome of colorectal cancer patients to further identify its role in colorectal cancer. PBK/TOPK immunoreactivity was analyzed by immunohistochemistry in 162 cancer specimens from primary colorectal cancer patients.

Results

The mean follow-up time after surgery was 5.4 years (medium: 3.9 years; range 0.01 to 13.1 years). The prognostic value of PBK/TOPK on overall survival was determined by Kaplan-Meier analysis and Cox proportional hazard models. PBK/TOPK was expressed in both the cytoplasm and nucleus. High PBK/TOPK expression in tumor cells was significantly associated with advanced T value. The 5-year survival rate was greater for patients with high total PBK/TOPK expression than with low PBK/TOPK expression (58.3% vs 34.4%, P = 0.005). Multivariate analyses showed that low-scoring cytoplasmic PBK/TOPK, negative nuclear PBK/TOPK, low total PBK/TOPK, and advanced tumor stage were correlated with poor overall patient survival.

Conclusions

We suggest that PBK/TOPK expression, detected by IHC staining, could be used as an independent prognostic marker for colorectal cancer patients.

Bioinformatics analysis of gene expression profiles to diagnose crucial and novel genes in glioblastoma multiform

Therefore, the current study aimed to diagnose the genes associated in the pathogenesis of GBM. The differentially expressed genes (DEGs) were diagnosed using the limma software package. The ToppFun was used to perform pathway and Gene Ontology (GO) enrichment analysis of the DEGs. Protein-protein interaction (PPI) networks, extracted modules, miRNA-target genes regulatory network and miRNA-target genes regulatory network were used to obtain insight into the actions of DEGs. Survival analysis for DEGs carried out. A total of 701 DEGs, including 413 upregulated and 288 downregulated genes, were diagnosed between U1118MG cell line (PK 11195 treated with 1 h exposure) and U1118MG cell line (PK 11195 treated with 24 h exposure). The up-regulated genes were enriched in superpathway of pyrimidine deoxyribonucleotides de novo biosynthesis, cell cycle, cell cycle process and chromosome. The down-regulated genes were enriched in folate transformations I, biosynthesis of amino acids, cellular amino acid metabolic process and vacuolar membrane. The current study screened the genes in PPI network, extracted modules, miRNA-target genes regulatory network and miRNA-target genes regulatory network with higher degrees as hub genes, which included MYC, TERF2IP, CDK1, EEF1G, TXNIP, SLC1A5, RGS4 and IER5L Survival suggested that low expressed NR4A2, SLC7 A5, CYR61 and ID1 in patients with GBM was linked with a positive prognosis for overall survival. In conclusion, the current study could improve our understanding of the molecular mechanisms in the progression of GBM, and these crucial as well as new molecular markers might be used as therapeutic targets for GBM.