The essential role of PIM kinases in sarcoma growth and bone invasion

Reconnoitering imidazopyridazines as anticancer agents based on virtual modelling approach: quantitative structure activity relationship, molecular docking and molecular dynamics

Cancer is an unimpeded growth of cells leading to metathesis of cancer and eventually spread throughout the body. PIM kinases are the members of the serine threonine kinase playing role in cancer progression, differentiation and proliferation. Till date there is no single drug targeting PIM-1 kinase in the market, that has made itself a target in limelight for the discover of new anticancer agents. The contemporary research focusses on the development of new inhibitors of PIM-1 kinase by application of ligand-based and structure-based perspective of drug discovery namely 3D-QSAR, molecular docking and dynamics. The following study stated the correlation amid structural and biological activity of the compounds employing 3D-QSAR analysis. Three 3D-QSAR models were generated using 33 molecules from which the excellent model stated an encouraging conventional correlation coefficient (r2) 0.8651, cross validation coefficient (q2) 0.7609. Furthermore, the predicted correlation coefficient (r2 pred) 0.6274, respectively. Molecular docking studies revealed that the most active compound 26 resided in the active pocket of PIM-1 kinase establishing hydrogen bond interactions with Asp186 in the DFG motif; similarly, all other molecules were engaged within the active site of the PIM-1 kinase. Moreover, molecular dynamics simulation study stated the stability of the ligand in the active site of PIM-1 kinase protein by developing two hydrogen bonds throughout the trajectory of 100 ns. In nutshell, the output stated the successful application of ligand and structure-based strategy for the development of novel PIM-1 kinase inhibitors as anticancer agents.Communicated by Ramaswamy H. Sarma.

PIM3-AMPK-HDAC4/5 axis restricts MuERVL-marked 2-cell-like state in embryonic stem cells

A minority of embryonic stem cells (ESCs) marked by endogenous retrovirus MuERVL are totipotent 2-cell-like cells. However, the majority of ESCs repress MuERVL. Currently, it is still unclear regarding the signaling pathway(s) repressing the MuERVL-associated 2-cell-like state of ESCs. Here, we identify the PIM3-downstream signaling axis as a key route to repress MuERVL and 2-cell-like state. Downregulation, deletion, or inhibition of PIM3 activated MuERVL, 2-cell genes, and trophectodermal genes in ESCs. By screening PIM3-regulated pathways, we discovered AMPK as its key target. The loss of Pim3 caused an increase in AMPK phosphorylation, which phosphorylated HDAC4/5 and triggered their transfer out of the nucleus in Pim3^−/− ESCs. The reduction of nuclear HDAC4/5 caused increased H3K9ac and reduced H3K9me1/2 enrichment on MuERVL, thus activating MuERVL and 2-cell-like state. In summary, our study uncovers a novel axis by which PIM3 suppresses 2-cell marker MuERVL and totipotent state in ESCs.

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PIM3 signaling pathway represses MuERVL and 2-cell-like state

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Pim3 loss promotes AMPK phosphorylation, which activates MuERVL

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Phosphorylated AMPK mediates HDAC4/5 export from the nucleus

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HDAC4/5 repress MuERVL through modulating H3K9ac and H3K9me1/2

The Role of PIM Kinases in Pediatric Solid Tumors

PIM kinases have been identified as potential therapeutic targets in several malignancies. Here, we provide an in-depth review of PIM kinases, including their structure, expression, activity, regulation, and role in pediatric carcinogenesis. Also included is a brief summary of the currently available pharmaceutical agents targeting PIM kinases and existing clinical trials.

ERK5 Is a Major Determinant of Chemical Sarcomagenesis: Implications in Human Pathology

Simple Summary

Sarcoma is a heterogeneous group of tumors poorly studied with few therapeutic opportunities. Interestingly, the role of MAPKs still remains unclear in sarcomatous pathology. Here, we describe for the first time the critical role of ERK5 in the biology of soft tissue sarcoma by using in vitro and in vivo approaches in a murine experimental model of chemical sarcomagenesis. Indeed, our observations were extrapolated to a short series of human leiomyosarcoma and rhabdomyosarcomas. Furthermore, transcriptome analysis allows us to demonstrate the critical role of KLF2 in the biological effects of ERK5. Therefore, the data presented here open new windows in the diagnosis and therapy of soft tissue sarcomas.

Abstract

Sarcomas are a heterogeneous group of tumors in which the role of ERK5 is poorly studied. To clarify the role of this MAPK in sarcomatous pathology, we used a murine 3-methyl-cholanthrene (3MC)-induced sarcoma model. Our data show that 3MC induces pleomorphic sarcomas with muscle differentiation, showing an increased expression of ERK5. Indeed, this upregulation was also observed in human sarcomas of muscular origin, such as leiomyosarcoma or rhabdomyosarcoma. Moreover, in cell lines derived from these 3MC-induced tumors, abrogation of Mapk7 expression by using specific shRNAs decreased in vitro growth and colony-forming capacity and led to a marked loss of tumor growth in vivo. In fact, transcriptomic profiling in ERK5 abrogated cell lines by RNAseq showed a deregulated gene expression pattern for key biological processes such as angiogenesis, migration, motility, etc., correlating with a better prognostic in human pathology. Finally, among the various differentially expressed genes, Klf2 is a key mediator of the biological effects of ERK5 as indicated by its specific interference, demonstrating that the ERK5–KLF2 axis is an important determinant of sarcoma biology that should be further studied in human pathology.

Aberrant Activation of Cell-Cycle-Related Kinases and the Potential Therapeutic Impact of PLK1 or CHEK1 Inhibition in Uterine Leiomyosarcoma

PURPOSE

Uterine leiomyosarcoma is among the most aggressive gynecological malignancies. No effective treatment strategies have been established. This study aimed to identify novel therapeutic targets for uterine leiomyosarcoma based on transcriptome analysis and assess the preclinical efficacy of novel drug candidates.

EXPERIMENTAL DESIGN

Transcriptome analysis was performed using fresh-frozen samples of six uterine leiomyosarcomas and three myomas. The Ingenuity Pathway Analysis (IPA) was used to identify potential therapeutic target genes for uterine leiomyosarcoma. Afterward, our results were validated using three independent datasets, including 40 uterine leiomyosarcomas. Then, the inhibitory effects of several selective inhibitors for the candidate genes were examined using SK-UT-1, SK-LMS-1, and SKN cell lines.

RESULTS

We identified 512 considerably dysregulated genes in uterine leiomyosarcoma compared with myoma. The IPA revealed that the function of several genes, including CHEK1 and PLK1, were predicted to be activated in uterine leiomyosarcoma. Through an in vitro drug screening, PLK1 or CHEK1 inhibitors (BI-2536 or prexasertib) were found to exert a superior anticancer effect against cell lines at low nanomolar concentrations and induce cell-cycle arrest. In SK-UT-1 tumor-bearing mice, BI-2536 monotherapy remarkably suppressed tumorigenicity. Moreover, the prexasertib and cisplatin combination therapy inhibited tumor proliferation and prolonged the time to tumor progression.

CONCLUSIONS

We identified upregulated expressions of PLK1 and CHEK1; their kinase activity was activated in uterine leiomyosarcoma. BI-2536 and prexasertib demonstrated a significant anticancer effect. Therefore, cell-cycle-related kinases may present a promising therapeutic strategy for the treatment of uterine leiomyosarcoma.

CRISPR/Cas9-mediated knockout of PIM3 suppresses tumorigenesis and cancer cell stemness in human hepatoblastoma cells

Hepatoblastoma remains one of the most difficult childhood tumors to treat and is alarmingly understudied. We previously demonstrated that Proviral Insertion site in Maloney murine leukemia virus (PIM) kinases, specifically PIM3, are overexpressed in human hepatoblastoma cells and function to promote tumorigenesis. We aimed to use CRISPR/Cas9 gene editing with dual gRNAs to introduce large inactivating deletions in the PIM3 gene and achieve stable PIM3 knockout in the human hepatoblastoma cell line, HuH6. PIM3 knockout of hepatoblastoma cells led to significantly decreased proliferation, viability, and motility, inhibited cell-cycle progression, decreased tumor growth in a xenograft murine model, and increased animal survival. Analysis of RNA sequencing data revealed that PIM3 knockout downregulated expression of pro-migratory and pro-invasive genes and upregulated expression of genes involved in apoptosis and differentiation. Furthermore, PIM3 knockout decreased hepatoblastoma cancer cell stemness as evidenced by decreased tumorsphere formation, decreased mRNA abundance of stemness markers, and decreased cell surface expression of CD133, a marker of hepatoblastoma stem cell-like cancer cells. Reintroduction of PIM3 into PIM3 knockout cells rescued the malignant phenotype. Successful CRISPR/Cas9 knockout of PIM3 kinase in human hepatoblastoma cells confirmed the role of PIM3 in promoting hepatoblastoma tumorigenesis and cancer cell stemness.

Regulation of sarcomagenesis by the empty spiracles homeobox genes EMX1 and EMX2

The EMX (Empty Spiracles Homeobox) genes EMX1 and EMX2 are two homeodomain gene members of the EMX family of transcription factors involved in the regulation of various biological processes, such as cell proliferation, migration, and differentiation, during brain development and neural crest migration. They play a role in the specification of positional identity, the proliferation of neural stem cells, and the differentiation of certain neuronal cell phenotypes. In general, they act as transcription factors in early embryogenesis and neuroembryogenesis from metazoans to higher vertebrates. The EMX1 and EMX2's potential as tumor suppressor genes has been suggested in some cancers. Our work showed that EMX1/EMX2 act as tumor suppressors in sarcomas by repressing the activity of stem cell regulatory genes (OCT4, SOX2, KLF4, MYC, NANOG, NES, and PROM1). EMX protein downregulation, therefore, induced the malignance and stemness of cells both in vitro and in vivo. In murine knockout (KO) models lacking Emx genes, 3MC-induced sarcomas were more aggressive and infiltrative, had a greater capacity for tumor self-renewal, and had higher stem cell gene expression and nestin expression than those in wild-type models. These results showing that EMX genes acted as stemness regulators were reproduced in different subtypes of sarcoma. Therefore, it is possible that the EMX genes could have a generalized behavior regulating proliferation of neural crest-derived progenitors. Together, these results indicate that the EMX1 and EMX2 genes negatively regulate these tumor-altering populations or cancer stem cells, acting as tumor suppressors in sarcoma.

p38β (MAPK11) mediates gemcitabine-associated radiosensitivity in sarcoma experimental models

BACKGROUND AND PURPOSE

Gemcitabine is an antitumour agent currently used in the treatment of several types of cancer with known properties as a radiosensitizer. p38MAPK signalling pathway has been shown to be a major determinant in the cellular response to gemcitabine in different experimental models. However, the molecular mechanism implicated in gemcitabine-associated radiosensitivity remains unknown.

MATERIALS AND METHODS

The human sarcoma cell lines A673 and HT1080, and a mouse cell line derived from a 3-methylcholanthrene induced sarcoma were used as experimental models. Modulation of p38MAPKs was performed by pharmacological approaches (SB203580) and genetic interference using lentiviral vectors coding for specific shRNAs. Viability was assessed by MTT. Gene expression was evaluated by western blot and RT-qPCR. Induction of apoptosis was monitored by caspase 3/7 activity. Response to ionizing radiation was evaluated by clonogenic assays.

RESULTS

Our data demonstrate that chemical inhibition of p38MAPK signalling pathway blocks gemcitabine radiosensitizing potential. Genetic interference of MAPK14 (p38α), the most abundantly expressed and best characterized p38MAPK, despite promoting resistance to gemcitabine, it does not affect its radiosensitizing potential. Interestingly, specific knockdown of MAPK11 (p38β) induces a total loss of the radiosensitivity associated to gemcitabine, as well as a marked increase in the resistance to the drug.

CONCLUSION

The present work identifies p38β as a major determinant of the radiosensitizing potential of gemcitabine without implication of p38α, suggesting that p38β status should be analysed in those cases in which gemcitabine is combined with ionizing radiation.

PAI1 is a Marker of Bad Prognosis in Rectal Cancer but Predicts a Better Response to Treatment with PIM Inhibitor AZD1208

Colorectal cancer (CRC) is the third most common cancer worldwide. The standard treatment in locally advanced rectal cancer is preoperative radiation alone or in combination with chemotherapy, followed by adjuvant chemotherapy. Rectal cancer is highly lethal, with only 20% of patients showing a complete remission (by RECIST) after standard treatment, although they commonly show local or systemic relapse likely due to its late detection and high chemotherapy resistance, among other reasons. Here, we explored the role of PAI1 (Serpin E1) in rectal cancer through the analyses of public patient databases, our own cohort of locally advanced rectal cancer patients and a panel of CRC cell lines. We showed that PAI1 expression is upregulated in rectal tumors, which is associated with decreased overall survival and increased metastasis and invasion in advanced rectal tumors. Accordingly, PAI1 expression is correlated with the expression of (Epithelial-to-Mesenchymal Transition) EMT-associated genes and genes encoding drug targets, including the tyrosine kinases PDGFRb, PDGFRa and FYN, the serine/threonine kinase PIM1 and BRAF. In addition, we demonstrate that cells expressing PAI1 protein are more sensitive to the PIM inhibitor AZD1208, suggesting that PAI1 could be used to predict response to treatment with PIM inhibitors and to complement radiotherapy in rectal tumors.

The acute transcriptome response of the midbrain/diencephalon to injury in the adult mummichog (Fundulus heteroclitus)

Adult fish produce new cells throughout their central nervous system during the course of their lives and maintain a tremendous capacity to repair damaged neural tissue. Much of the focus on understanding brain repair and regeneration in adult fish has been directed at regions of the brainstem and forebrain; however, the mesencephalon (midbrain) and diencephalon have received little attention. We sought to examine differential gene expression in the midbrain/diencephalon in response to injury in the adult fish using RNA-seq. Using the mummichog (Fundulus heteroclitus), we administered a mechanical lesion to the midbrain/diencephalon and examined differentially expressed genes (DEGs) at an acute recovery time of 1 h post-injury. Comparisons of whole transcriptomes derived from isolated RNA of intact and injured midbrain/diencephalic tissue identified 404 DEGs with the vast majority being upregulated. Using qPCR, we validated the upregulation of DEGs pim-2-like, syndecan-4-like, and cd83. Based on genes both familiar and novel regarding the adult brain response to injury, these data provide an extensive molecular profile giving insight into a range of cellular processes involved in the injury response of a brain regenerative-capable vertebrate.

Inhibition of PIM2 in liver cancer decreases tumor cell proliferation in vitro and in vivo primarily through the modulation of cell cycle progression

Liver cancer is the fourth leading cause of cancer-related mortality worldwide with limited therapeutic options. Thus, novel treatment strategies are urgently required. While the oncogenic kinase, proviral integration site for Moloney murine leukemia virus 2 (PIM2), has been shown to be overexpressed in liver cancer, little is known about the role of PIM2 in this tumor entity. In this study, we explored the functional relevance and therapeutic potential of PIM2 in liver cancer. Using PIM2-specific siRNAs, we examined the effects of PIM2 knockdown on proliferation (WST-1 assays and spheroid assays), 3D-colony formation and colony spread, apoptosis (flow cytometry and caspase 3/caspase 7 activity), as well as cell cycle progression (flow cytometry, RT-qPCR and western blot analysis) in the two liver cancer cell lines, HepG2 and Huh-7. In subcutaneous liver cancer xenografts, we assessed the effects of PIM2 knockdown on tumor growth via the systemic delivery of polyethylenimine (PEI)-complexed siRNA. The knockdown of PIM2 resulted in potent anti-proliferative effects in cells grown on plastic dishes, as well as in spheroids. This was due to G0/G1 cell cycle blockade and the subsequent downregulation of genes related to the S phase as well as the G2/M phase of the cell cycle, whereas the apoptotic rates remained unaltered. Furthermore, colony formation and colony spread were markedly inhibited by PIM2 knockdown. Notably, we found that HepG2 cells were more sensitive to PIM2 knockdown than the Huh-7 cells. In vivo, the therapeutic nanoparticle-mediated delivery of PIM2 siRNA led to profound anti-tumor effects in a liver cancer xenograft mouse model. On the whole, the findings of this study underscore the oncogenic role of PIM2 and emphasize the potential of targeted therapies based on the specific inhibition of PIM2 in liver cancer.

PIM kinase inhibitors: Structural and pharmacological perspectives

The PIM kinase, also known as serine/threonine kinase plays an important role in cancer biology and is found in three different isoforms namely PIM-1, PIM-2, and PIM-3. They are extensively distributed and are implicated in a variety of biological processes, including cell proliferation, cell differentiation, and apoptosis. They act as weak oncogene and whenever expressed in exacerbating forms are responsible for different types of human cancer. Recently, different isoforms of PIM kinase have been identified as a clinical biomarker and potential therapeutic target for personalized treatment of advanced cancer. The inhibition of PIM kinase has become a scientific interest and some inhibitors have been developed and/or are under different phases of clinical trials. Several medicinally privileged heterocyclic ring scaffolds such as pyrrole, pyrimidine, thiazolidine, benzofuran, indole, triazole, oxadiazole, and quinoline derivatives have been synthesized and evaluated for their PIM inhibitory activity. This review comprehensively focuses on pharmacological implications of PIM kinases in oncogenesis, structural insights of PIM inhibitors and their structure-activity relationships (SARs).

Thyroid hormone inhibits growth of hepatoma cells through induction of miR-214

Thyroid hormone (TH) plays a role in regulating the metabolic rate, heart functions, muscle control and maintenance of bones. 3,3′5-tri-iodo-L-thyronine (T₃) displays high affinity to nuclear thyroid hormone receptors (TRs), which mediate most TH actions. Recent studies have shown hypothyroidism in patients with an increased risk of hepatocellular carcinoma (HCC). MicroRNAs (miRNAs), a class of non-protein-coding RNA, are suggested to control tumor growth by interacting with target genes. However, the clinical significance of T₃/TR-regulated miRNAs in tumors has yet to be established. In the current study, miRNA expression profile screening was performed using SYBR Green-Based qRT-PCR array in TR-overexpressing HepG2 cells. miR-214-3p, which is expressed at low levels in HCC, was stimulated upon T₃ application. The 3′UTR luciferase reporter assay confirmed that the proto-oncogene serine/threonine-protein kinase, PIM-1, is a miR-214-3p target. PIM-1 was decreased upon treatment with miR-214-3p or T₃ stimulation. PIM-1 was highly expressed in HCC, and the effect of PIM-1 on cell proliferation might be mediated by the inhibition of p21. Furthermore, the T₃-induced suppression of cell proliferation was partially rescued upon miR-214-3p knockdown. Our data demonstrate that T₃ induces miR-214-3p expression and suppresses cell proliferation through PIM-1, thus contributing to the inhibition of HCC tumor formation.

Inflammation and stem markers association to PIM1/PIM2 kinase-induced tumors in breast and uterus

The PIM family of Ser/Thr kinase proteins has been implicated in tumorigenesis at different levels. PIM proteins are overexpressed in several tumor types and have been associated with chemoresistance. However, their role in hormone-dependent female tissues has not been explored, especially in the uterus, breast and ovary. We generated conditional transgenic mice with confined expression of human PIM1 or PIM2 genes in these tissues. We characterized the tumoral response to these genetic alterations corroborating their role as oncogenes since they induce hyperproliferation in all tissues and tumors in mammary gland and uterus. Furthermore, we observed a high degree of inflammatory infiltration in these tissues of transgenic mice accompanied by NFAT and mTOR activation and IL6 expression. Moreover, PIM1/2 were overexpressed in human breast, uterine and ovarian tumors, correlating with inflammatory features and stem cell markers. Our data suggest that PIM1/2 kinase overexpression provoke tissue alterations and a large IL6-dependent inflammatory response that may act synergistically during the process of tumorigenesis. The possible end-point is an increased percentage of cancer stem cells, which may be partly responsible for the therapy resistance found in tumors overexpressing PIM kinases.

Thiazolidine derivatives as potent and selective inhibitors of the PIM kinase family

The PIM family of serine/threonine kinases have become an attractive target for anti-cancer drug development, particularly for certain hematological malignancies. Here, we describe the discovery of a series of inhibitors of the PIM kinase family using a high throughput screening strategy. Through a combination of molecular modeling and optimization studies, the intrinsic potencies and molecular properties of this series of compounds was significantly improved. An excellent pan-PIM isoform inhibition profile was observed across the series, while optimized examples show good selectivity over other kinases. Two PIM-expressing leukemic cancer cell lines, MV4-11 and K562, were employed to evaluate the in vitro anti-proliferative effects of selected inhibitors. Encouraging activities were observed for many examples, with the best example (44) giving an IC₅₀ of 0.75μM against the K562 cell line. These data provide a promising starting point for further development of this series as a new cancer therapy through PIM kinase inhibition.

Expression and function of PIM kinases in osteosarcoma

The provirus integrating site Moloney murine leukemia virus (PIM) family of serine/threonine protein kinases is composed of three members, PIM1, PIM2 and PIM3, which have been identified as oncoproteins in various malignancies. However, their role in osteosarcoma (OS) remains largely unknown. This study aimed to examine the expression patterns and the clinical significance of PIM kinases in human OS and their biological effects in human OS cell lines. Immunohistochemical staining was used to detect PIM kinases in archived pathologic material from 43 patients with primary OS; in addition, the effects of PIM knockdown and overexpression on the proliferation, migration and invasion of OS cell lines were determined. We observed that all three PIM kinases were frequently expressed in OS, but only PIM1 positive expression was associated with poorer prognosis regarding overall survival of OS patients. In addition, knockdown of PIM kinases notably inhibited OS cell proliferation, migration and invasiveness, whereas overexpression of PIM kinases resulted in increased OS cell growth and motility. This study suggests that PIM1 could be a valuable prognostic marker in patients with OS, and the biological functions of PIM kinase family in the osteosarcoma cell lines indicate that they could serve as potential therapeutic targets for OS.

Interleukin-9 promotes cell survival and drug resistance in diffuse large B-cell lymphoma

Background

Interleukin-9 (IL-9) was discovered as a helper T cell growth factor. It has long been recognized as an important regulator in allergic inflammation. Recent years it was discovered to induce cell growth and differentiation of multiple transformed cells. However, its oncogenic activities in B-cell lymphomas have not been reported in detail.

Methods

Serum levels of IL-9 in DLBCL patients were quantified by ELISA, and its clinical significance was analysed. The expression of IL-9 receptor (IL-9R) was investigated in lymphoma cell lines by RT-PCR and western blot, respectively. In DLBCL cell lines LY1 and LY8, IL-9R genes were knocked down by RNA interference and stable transfected cells were selected with puromycin. Normal and final siIL-9R (and siControl) LY1 and LY8 cells were treated with IL-9 alone and in synergy with chemotherapeutic drugs. Cell proliferation and apoptosis were assessed by Brdu incorporation and flow cytometric analysis. The mRNA of apoptosis regulation genes were measured with real-time PCR.

Results

Elevated serum levels of IL-9 were detected in DLBCL patients (24/30) compared to healthy controls (0/15). Positive expression of IL-9 (defined as a serum level ≥1 pg/ml) was correlated with lower serum albumin levels and high international prognostic index (IPI) scores. IL-9R was expressed in both mRNA and protein levels in the five lymphoma cell lines, including LY1, LY8, MINO, SP53 and Jurkat. In vitro studies showed that IL-9 directly induced proliferation and inhibited apoptosis in LY1 and LY8 cells. It protects LY1 and LY8 cells from prednisolone induced apoptosis, and promotes their proliferation that were inhibited by rituximab, vincristine and prednisolone. Its molecular mechanism may be concerned with upregulating expression of p21CIP1 gene. Knock-down of IL-9R gene could reverse the effects of IL-9 on LY1 and LY8 cells.

Conclusions

IL-9 is associated with clinical features of DLBCL patients. It promotes survival of DLBCL cells and reduces the sensitivities of tumor cells to chemotherapeutic drugs via upregulation of p21CIP1 genes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0374-3) contains supplementary material, which is available to authorized users.

Clinical and biological significance of PIM1 kinase in osteosarcoma

Osteosarcoma is the most prevalent histological form of primary malignant bone tumor. The majority of osteosarcoma patients have limited alternative therapeutic options and metastatic patients generally have a poor prognosis. Proto-oncogene serine/threonine-protein kinase PIM1 is associated with growth and survival of many kinds of tumor cells. However, the role of PIM1 in osteosarcoma remains largely unknown. In this study, we investigated the functional and therapeutic relevance of PIM1 as a putative target in osteosarcoma. We found PIM1 was highly expressed in various osteosarcoma cell lines and in tumor tissues from osteosarcoma patients. Tissue microarray and immunohistochemistry analysis showed that the overall and disease-free survival rate of patients with high levels of PIM1 protein expression were significantly shorter than patients with low levels. High levels of PIM1 were also associated with present metastasis and can be considered as an independent prognostic factor in osteosarcoma patients. Knockdown of PIM1 expression by synthetic siRNA or shRNA greatly inhibited cell growth, migration, and invasion. Moreover, these changes accompanied with down-regulation of anti-apoptotic protein Bcl-2. The similar results were obtained in osteosarcoma cells treated with PIM1 specific inhibitor (SMI-4a). These results suggest that PIM1 kinase is critical for the growth and metastasis of osteosarcoma cells and can be a potential therapeutic target for osteosarcoma treatment. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1185-1194, 2016.

Computational prediction and experimental validation of a novel synthesized pan-PIM inhibitor PI003 and its apoptosis-inducing mechanisms in cervical cancer

PIM protein family, short-lived serine/threonine kinases (PIM1, PIM2 and PIM3), are weak oncogenes but contribute to tumorigenesis as cancer targets. Thus, design of a novel pan-PIM inhibitor is still a challenge for current cancer drug discovery. Herein, we used a Naïve Bayesian model to construct the PIM network and identified Bad and Hsp90 to interact with PIMs. Then, we screened a series of candidate small-molecule compounds targeting PIMs, and subsequently synthesized a novel small-molecule compound PI003 with remarkable anti-proliferative activities in cervical cancer cells. Moreover, we found that PI003 induced apoptosis via the death-receptor and mitochondrial pathways by targeting PIMs and affecting Bad and Hsp90. Combined with microRNA microarray analyses, we demonstrated that some microRNAs such as miR-1296 and miR-1299 could affect PIM1-STAT3 pathway in PI003-induced apoptosis. Finally, we reported that PI003 had remarkable anti-tumor activity and apoptosis-inducing effect in in vivo mouse model. In conclusion, these results demonstrate that PI003, as a novel synthesized pan-PIM inhibitor, induces the death-receptor and mitochondrial apoptosis involved in microRNA regulation, and also possessed remarkable anti-tumor activity and apoptosis-inducing effect in vivo. Thus, these findings would shed light on discovering more potential new small-molecule pan-PIM inhibitors in future cervical cancer therapy.

Aberrant expression of pim-3 promotes proliferation and migration of ovarian cancer cells

Pim kinase-3(Pim-3), a member of serine/threonine protein kinases, has been implicated in multiple human cancers and involved in Myc-induced tumorigenesis. However, little is known regarding its expression and biological function in human ovarian cancer. In this study we showed that the clinical significance and biological functions of Pim-3 in ovarian cancer and found that higher Pim-3 mRNA level are detected in ovarian cancer tissues than those in normal ovarian tissues. There are significant correlations between higher Pim-3 expression levels with the FIGO stage, histopathological subtypes, and distant metastasis in ovarian cancer patients. Lentivirus-mediated gene overexpression of Pim-3 significantly promotes the proliferation and migration of SKOV3 cell lines. Furthermore, MACC1 and Pim-3 expression were significantly correlated in human ovarian cancer cells, and overexpression of Pim-3 in ovary cancer cells increased MACC1 mRNA and protein expression. The data indicate that Pim-3 acts as a putative oncogene in ovary cancer and could be a viable diagnostic and therapeutic target for ovarian cancer.

Patterns and Significance of PIM Kinases in Urothelial Carcinoma

BACKGROUND

The Provirus integrating site Moloney murine leukemia virus (Pim) family are proteins with serine/threonine kinase activity. Studies have demonstrated overexpression of Pims in cancer. To our knowledge, only a single study has examined Pim-1 in urothelial carcinoma. The aim of this investigation was to evaluate Pim-1, Pim-2, and Pim-3 in urothelial carcinoma and assess for expression that may contribute to disease progression and serve as a site for targeted therapy.

METHODS

This retrospective study included 137 cases taken from specimens from the University of Utah, Department of Pathology (2008 to 2011). Tissue was stained with antibodies against Pim-1, Pim-2, and Pim-3. Cases were classified into 3 groups, based upon current World Health Organization criteria (invasive high-grade urothelial carcinoma [IHG] [n=84], noninvasive high-grade urothelial carcinoma/carcinoma in situ [n=32], and noninvasive low-grade urothelial carcinoma [NILG] [n=21]). Cases were scored and recorded as positive or negative on the basis of the percentage of cells with cytoplasmic and/or nuclear staining.

RESULTS

NILG showed higher expression of Pim-1 (relative expression rate [RER]=2.28; 95% confidence interval [CI], 0.183-0.764) and Pim-3 (RER=3.06; 95% CI, 0.423-0.816) compared with other lesions. IHG had lower expression of Pim-1 (RER=0.31; 95% CI, 0.401-0.844) and Pim-3 (RER=0.354; 95% CI, 0.322-0.816) and noninvasive high-grade urothelial carcinoma (NIHG) demonstrated increased expression of Pim-1 and (RER=2.09; 95% CI, 0.124-0.739) and Pim-2 (RER=1.70; 95% CI, 0.151-0.591). At least 1 Pim kinase protein was expressed at the following rates: 49% in IHG, 66% in NIHG, and 76% in NILG.

CONCLUSION

A high percentage of urothelial carcinomas express Pim kinases. Pim expression differs in NILG, NIHG, and IHG lesions.

PIM kinase (and Akt) biology and signaling in tumors

The initiation and progression of human cancer is frequently linked to the uncontrolled activation of survival kinases. Two such pro-survival kinases that are commonly amplified in cancer are PIM and Akt. These oncogenic proteins are serine/threonine kinases that regulate tumorigenesis by phosphorylating substrates that control the cell cycle, cellular metabolism, proliferation, and survival. Growing evidence suggests that cross-talk exists between the PIM and Akt kinases, indicating that they control partially overlapping survival signaling pathways that are critical to the initiation, progression, and metastatic spread of many types of cancer. The PI3K/Akt signaling pathway is activated in many human tumors, and it is well established as a promising anticancer target. Likewise, based on the role of PIM kinases in normal and tumor tissues, it is clear that this family of kinases represents an interesting target for anticancer therapy. Pharmacological inhibition of PIM has the potential to significantly influence the efficacy of standard and targeted therapies. This review focuses on the regulation of PIM kinases, their role in tumorigenesis, and the biological impact of their interaction with the Akt signaling pathway on the efficacy of cancer therapy.

PIM kinases: an overview in tumors and recent advances in pancreatic cancer

The PIM kinases represent a family of serine/threonine kinases, which is composed of three different members (PIM1, PIM2 and PIM3). Aberrant expression of PIM kinases is observed in variety of tumors, including pancreatic cancer. The PIM kinases play pivotal roles in the regulation of cell cycle, apoptosis, properties of stem cells, metabolism, autophagy, drug resistance and targeted therapy. The roles of PIM kinases in pancreatic cancer include the regulation of proliferation, apoptosis, cell cycle, formation, angiogenesis and prediction prognosis. Blocking the activities of PIM kinases could prevent pancreatic cancer development. PIM kinases may be a novel target for cancer therapy.

The PTEN/PI3K/AKT Pathway in vivo, Cancer Mouse Models

When PI3K (phosphatidylinositol-3 kinase) is activated by receptor tyrosine kinases, it phosphorylates PIP2 to generate PIP3 and activates the signaling pathway. Phosphatase and tensin homolog deleted on chromosome 10 dephosphorylates PIP3 to PIP2, and thus, negatively regulates the pathway. AKT (v-akt murine thymoma viral oncogene homolog; protein kinase B) is activated downstream of PIP3 and mediates physiological processes. Furthermore, substantial crosstalk exists with other signaling networks at all levels of the PI3K pathway. Because of its diverse array, gene mutations, and amplifications and also as a consequence of its central role in several signal transduction pathways, the PI3K-dependent axis is frequently activated in many tumors and is an attractive therapeutic target. The preclinical testing and analysis of these novel therapies requires appropriate and well-tailored systems. Mouse models in which this pathway has been genetically modified have been essential in understanding the role that this pathway plays in the tumorigenesis process. Here, we review cancer mouse models in which the PI3K/AKT pathway has been genetically modified.

A selenosemicarbazone complex with copper efficiently down-regulates the 90-kDa heat shock protein HSP90AA1 and its client proteins in cancer cells

Background

The 90-kDa heat shock protein HSP90AA1 is critical for the stability of several proteins that are important for tumor progression and thus, is a promising target for cancer therapy. Selenosemicarbazone metal complexes have been shown to possess anticancer activity through an unknown molecular mechanism.

Methods

The MTT assay, fluorescence-activated cell sorting, and fluorescent microscopy were used to analyze the mechanism of the anti-cancer activity of the selenosemicarbazone metal complexes. Additionally, RNA-seq was applied to identify transcriptional gene changes, and in turn, the signaling pathways involved in the process of 2-24a/Cu-induced cell death. Last, the expression of HSP90AA1, HSPA1A, PIM1, and AKT proteins in 2-24a/Cu-treated cells were investigated by western blot analysis.

Results

A novel selenosemicarbazone copper complex (2-24a/Cu) efficiently induced G2/M arrest and was cytotoxic in cancer cells. 2-24a/Cu significantly induced oxidative stress in cancer cells. Interestingly, although RNA-seq revealed that the transcription of HSP90AA1 was increased in 2-24a/Cu-treated cells, western blotting showed that the expression of HSP90AA1 protein was significantly decreased in these cells. Furthermore, down-regulation of HSP90AA1 led to the degradation of its client proteins (PIM1 and AKT1), which are also cancer therapy targets.

Conclusion

Our results showed that 2-24a/Cu efficiently generates oxidative stress and down-regulates HSP90AA1 and its client proteins (PIM1, AKT1) in U2os and HeLa cells. These results demonstrate the potential application of this novel copper complex in cancer therapy.

Genetic Modeling of PIM Proteins in Cancer: Proviral Tagging and Cooperation with Oncogenes, Tumor Suppressor Genes, and Carcinogens

The PIM proteins, which were initially discovered as proviral insertion sites in Moloney-murine leukemia virus infection, are a family of highly homologous serine/threonine kinases that have been reported to be overexpressed in hematological malignancies and solid tumors. The PIM proteins have also been associated with metastasis and overall treatment responses and implicated in the regulation of apoptosis, metabolism, the cell cycle, and homing and migration, which makes these proteins interesting targets for anti-cancer drug discovery. The use of retroviral insertional mutagenesis and refined approaches such as complementation tagging has allowed the identification of myc, pim, and a third group of genes (including bmi1 and gfi1) as complementing genes in lymphomagenesis. Moreover, mouse modeling of human cancer has provided an understanding of the molecular pathways that are involved in tumor initiation and progression at the physiological level. In particular, genetically modified mice have allowed researchers to further elucidate the role of each of the Pim isoforms in various tumor types. PIM kinases have been identified as weak oncogenes because experimental overexpression in lymphoid tissue, prostate, and liver induces tumors at a relatively low incidence and with a long latency. However, very strong synergistic tumorigenicity between Pim1/2 and c-Myc and other oncogenes has been observed in lymphoid tissues. Mouse models have also been used to study whether the inhibition of specific PIM isoforms is required to prevent carcinogen-induced sarcomas, indicating that the absence of Pim2 and Pim3 greatly reduces sarcoma growth and bone invasion; the extent of this effect is similar to that observed in the absence of all three isoforms. This review will summarize some of the animal models that have been used to understand the isoform-specific contribution of PIM kinases to tumorigenesis.

Gene expression correlation for cancer diagnosis: a pilot study

Poor prognosis for late-stage, high-grade, and recurrent cancers has been motivating cancer researchers to search for more efficient biomarkers to identify the onset of cancer. Recent advances in constructing and dynamically analyzing biomolecular networks for different types of cancer have provided a promising novel strategy to detect tumorigenesis and metastasis. The observation of different biomolecular networks associated with normal and cancerous states led us to hypothesize that correlations for gene expressions could serve as valid indicators of early cancer development. In this pilot study, we tested our hypothesis by examining whether the mRNA expressions of three randomly selected cancer-related genes PIK3C3, PIM3, and PTEN were correlated during cancer progression and the correlation coefficients could be used for cancer diagnosis. Strong correlations (0.68 ≤ r ≤ 1.0) were observed between PIK3C3 and PIM3 in breast cancer, between PIK3C3 and PTEN in breast and ovary cancers, and between PIM3 and PTEN in breast, kidney, liver, and thyroid cancers during disease progression, implicating that the correlations for cancer network gene expressions could serve as a supplement to current clinical biomarkers, such as cancer antigens, for early cancer diagnosis.

The PIM family of serine/threonine kinases in cancer

The proviral insertion site in Moloney murine leukemia virus, or PIM proteins, are a family of serine/threonine kinases composed of three different isoforms (PIM1, PIM2, and PIM3) that are highly evolutionarily conserved. These proteins are regulated primarily by transcription and stability through pathways that are controlled by Janus kinase/Signal transducer and activator of transcription, JAK/STAT, transcription factors. The PIM family proteins have been found to be overexpressed in hematological malignancies and solid tumors, and their roles in these tumors were confirmed in mouse tumor models. Furthermore, the PIM family proteins have been implicated in the regulation of apoptosis, metabolism, cell cycle, and homing and migration, which has led to the postulation of these proteins as interesting targets for anticancer drug discovery. In the present work, we review the importance of PIM kinases in tumor growth and as drug targets.

Conditional transgenic expression of PIM1 kinase in prostate induces inflammation-dependent neoplasia

The Pim proteins are a family of highly homologous protein serine/threonine kinases that have been found to be overexpressed in cancer. Elevated levels of Pim1 kinase were first discovered in human leukemia and lymphomas. However, more recently Pim1 was found to be increased in solid tumors, including pancreatic and prostate cancers, and has been proposed as a prognostic marker. Although the Pim kinases have been identified as oncogenes in transgenic models, they have weak transforming abilities on their own. However, they have been shown to greatly enhance the ability of other genes or chemical carcinogens to induce tumors. To explore the role of Pim1 in prostate cancer, we generated conditional Pim1 transgenic mice, expressed Pim1 in prostate epithelium, and analyzed the contribution of PIM1 to neoplastic initiation and progression. Accordingly, we explored the effect of PIM1 overexpression in 3 different settings: upon hormone treatment, during aging, and in combination with the absence of one Pten allele. We have found that Pim1 overexpression increased the severity of mouse prostate intraepithelial neoplasias (mPIN) moderately in all three settings. Furthermore, Pim1 overexpression, in combination with the hormone treatment, increased inflammation surrounding target tissues leading to pyelonephritis in transgenic animals. Analysis of senescence induced in these prostatic lesions showed that the lesions induced in the presence of inflammation exhibited different behavior than those induced in the absence of inflammation. While high grade prostate preneoplastic lesions, mPIN grades III and IV, in the presence of inflammation did not show any senescence markers and demonstrated high levels of Ki67 staining, untreated animals without inflammation showed senescence markers and had low levels of Ki67 staining in similar high grade lesions. Our data suggest that Pim1 might contribute to progression rather than initiation in prostate neoplasia.

Pim kinases in cancer: diagnostic, prognostic and treatment opportunities

PIM proteins belong to a family of ser/thr kinases composed of 3 members, PIM1, PIM2 and PIM3, with greatly overlapping functions. PIM kinases are mainly responsible for cell cycle regulation, antiapoptotic activity and the homing and migration of receptor tyrosine kinases mediated via the JAK/STAT pathway. PIM kinases have been found to be upregulated in many hematological malignancies and solid tumors. Although these kinases have been described as weak oncogenes, they are heavily targeted for anticancer drug discovery. The present review summarizes the discoveries made to date regarding PIM kinases as driving oncogenes in the process of tumorigenesis and their validation as drug targets.