A small-molecule inhibitor targeting the mitotic spindle checkpoint impairs the growth of uterine leiomyosarcoma

Potential Markers to Differentiate Uterine Leiomyosarcomas from Leiomyomas

Uterine leiomyomas (ULM) are the most common benign tumors of the female genitalia, while uterine leiomyosarcomas (ULMS) are rare. The sarcoma is diffuse growth, prone to hematogenous metastasis, and has a poor prognosis. Due to their similar clinical symptoms and morphological features, it is sometimes difficult to distinguish them, and the final diagnosis depends on histological diagnosis. Misdiagnosis of ULM as ULMS will lead to more invasive and extensive surgery when it is not needed, while misdiagnosis of ULMS as ULM may lead to delayed treatment and poor prognosis. This review searched and studied the published articles on ULM and ULMS, and summarized the potential markers for the differential diagnosis of ULMS. These markers will facilitate differential diagnosis and personalized treatment, providing timely diagnosis and potentially better prognosis for patients.

Downregulation of miR‑10b‑5p facilitates the proliferation of uterine leiomyosarcoma cells: A microRNA sequencing‑based approach

Uterine leiomyosarcoma (ULMS) is one of the most aggressive gynecological malignancies. In addition, the molecular background of ULMS has not been fully elucidated due to its low incidence. Therefore, no effective treatment strategies have been established based on its molecular background. The present study aimed to investigate the roles of microRNAs (miRNAs/miRs) in the development of ULMS. Comprehensive miRNA sequencing was performed using six ULMS and three myoma samples, and revealed 53 and 11 significantly upregulated and downregulated miRNAs, respectively. One of the most abundant miRNAs in myoma samples was miR‑10b‑5p. The mean normalized read count of miR‑10b‑5p was 93,650 reads in myoma, but only 27,903 reads in ULMS. Subsequently, to investigate the roles of miR‑10b‑5p, gain‑of‑function analysis was performed using SK‑UT‑1 and SK‑LMS‑1 cell lines. The overexpression of miR‑10b‑5p suppressed cell proliferation and reduced the number of colonies. Moreover, miR‑10b‑5p increased the number of cells in the G1 phase. In conclusion, tumor‑suppressive miR‑10b‑5p was significantly downregulated in ULMS compared with in myoma; thus, miR‑10b‑5p may serve a specific role in sarcoma progression.

The Expression of the Immunoproteasome Subunit PSMB9 Is Related to Distinct Molecular Subtypes of Uterine Leiomyosarcoma

Simple Summary

Uterine leiomyosarcoma (uLMS) is a rare, aggressive, and highly heterogeneous tumor. Knockout female mice for the catalytic subunit of the immunoproteasome PSMB9 develops spontaneous uLMS. In this study, we used molecular data from 3 non-related uLMS cohorts that were integrated and analyzed by proteotranscriptomics. We observed overexpression of the immunoproteasome pathway in uLMS, and then further classified the samples as low or high PSMB9 gene expression levels and we provide evidence that; (i) in the group high there is an enrichment of pathways related to the immune system and in the group low, the ECM formation; (ii) samples with high CD8+/PSMB9 ratio shows better OS; and (iii) the main regulator in the high group is IFNγ and in the low, the proto-oncogene SRC. These findings contribute to the understanding of potential therapeutic or prognostic markers in uLMS.

Abstract

Background: Uterine leiomyosarcoma (uLMS) are rare and malignant tumors that arise in the myometrium cells and whose diagnosis is based on histopathological features. Identifying diagnostic biomarkers for uLMS is a challenge due to molecular heterogeneity and the scarcity of samples. In vivo and in vitro models for uLMS are urgently needed. Knockout female mice for the catalytic subunit of the immunoproteasome PSMB9 (MIM:177045) develop spontaneous uLMS. This study aimed to analyze the role of PSMB9 in uLMS tumorigenesis and patient outcome. Methods: Molecular data from 3 non-related uLMS cohorts were integrated and analyzed by proteotranscriptomic using gene expression and protein abundance levels in 68 normal adjacent myometrium (MM), 66 uterine leiomyoma (LM), and 67 uLMS. Results: the immunoproteasome pathway is upregulated and the gene PMSB9 shows heterogeneous expression values in uLMS. Quartile group analysis showed no significant difference between groups high and low PSMB9 expression groups at 3-years overall survival (OS). Using CYBERSORTx analysis we observed 9 out of 17 samples in the high group clustering together due to high M2 macrophages and CD4 memory resting, and high CD8+/PSMB9 ratio was associated with better OS. The main pathway regulated in the high group is IFNγ and in the low is the ECM pathway dependent on the proto-oncogene SRC. Conclusion: these findings suggest 2 subtypes of uLMS (immune-related and ECM-related) with different candidate mechanisms of malignancy.

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.

FKBP51 Contributes to Uterine Leiomyoma Pathogenesis by Inducing Cell Proliferation and Extracellular Matrix Deposition

The FK506-binding protein 51 (FKBP51) binds progesterone receptor (PR), glucocorticoid receptor (GR), and androgen receptor (AR) to coregulate their transcriptional activity. We evaluated FKBP51 expression and function in human leiomyoma vs. myometrial tissues and primary cultures to discover FKBP51 role(s) in the pathogenesis of leiomyomas. Quantification of in situ FKBP51 mRNA and protein levels inpaired myometrial vs. leiomyoma tissues from proliferative and secretory phases were analyzed by qPCR (n = 14), immunoblotting (n = 20), and immunohistochemistry (n = 12). Control (scramble) vs. FKBP5 siRNA-transfected leiomyoma cell cultures were assessed for proliferation, apoptosis, and mRNA levels of genes involved in cell survival and extracellular matrix (ECM) formation. Significantly higher FKBP5 mRNA levels were detected in leiomyoma vs. paired myometrium (P < 0.001). Immunoblot (P = 0.001) and immunostaining (P ≤ 0.001) confirmed increased FKBP51 levels in leiomyoma vs. paired myometrium. Compared to control siRNA transfection, FKBP5-silenced leiomyoma cell cultures displayed significantly decreased cell survival factors and reduced proliferation (P < 0.05). Moreover, qPCR analysis revealed significantly lower mRNA levels of ECM, TIPM1, and TIPM3 proteins in FKBP5-silenced leiomyoma cell cultures (P < 0.05). Increased FKBP51 expression in leiomyoma likely involves dysregulation of steroid signaling by blocking GR and PR action and promoting proliferation and ECM production. Evaluating the effect of FKBP51 inhibition in preclinical studies will clarify its significance as a potential therapeutic approach against leiomyoma.

Integrative Genomic and Transcriptomic Profiling Reveals a Differential Molecular Signature in Uterine Leiomyoma versus Leiomyosarcoma

The absence of standardized molecular profiling to differentiate uterine leiomyosarcomas versus leiomyomas represents a current diagnostic challenge. In this study, we aimed to search for a differential molecular signature for these myometrial tumors based on artificial intelligence. For this purpose, differential exome and transcriptome-wide research was performed on histologically confirmed leiomyomas (n = 52) and leiomyosarcomas (n = 44) to elucidate differences between and within these two entities. We identified a significantly higher tumor mutation burden in leiomyosarcomas vs. leiomyomas in terms of somatic single-nucleotide variants (171,863 vs. 81,152), indels (9491 vs. 4098), and copy number variants (8390 vs. 5376). Further, we discovered alterations in specific copy number variant regions that affect the expression of some tumor suppressor genes. A transcriptomic analysis revealed 489 differentially expressed genes between these two conditions, as well as structural rearrangements targeting ATRX and RAD51B. These results allowed us to develop a machine learning approach based on 19 differentially expressed genes that differentiate both tumor types with high sensitivity and specificity. Our findings provide a novel molecular signature for the diagnosis of leiomyoma and leiomyosarcoma, which could be helpful to complement the current morphological and immunohistochemical diagnosis and may lay the foundation for the future evaluation of malignancy risk.

Current molecular and therapeutic advances in liposarcoma, rhabdomyosarcoma, leiomyosarcoma, synovial sarcoma, and angiosarcoma

Sarcomas probably develop after malignant transformation of embryonic mesenchymal cells and have broad spectrum histopathologically since they can develop from striated skeletal muscle and smooth muscle, fat and fibrous tissue, bone, cartilage and other mesenchymal tissues. The most common histological subtypes of soft tissue sarcoma in adults are: liposarcoma, leiomyosarcoma, poorly differentiated pleomorphic sarcoma, and gastrointestinal stromal tumor. Molecular and genetic studies of soft tissue sarcomas, which are considered as heterogeneous groups in terms of their molecular and clinical characteristics, are still an important area of ​​interest The heterogeneity of the molecular and genetic alterations of these malignancies, which are mostly treated with surgery and chemotherapy, also offers hope to the researchers in terms of treatment targets. In this article, molecular biologic features of the soft tissue sarcomas including liposarcoma, rhabdomyosarcoma, leiomyosarcoma, synovial sarcoma, and angiosarcoma are discussed in the light of recent developments in molecular biology, targeted therapies and immunotherapy.

Blocking AURKA with MK-5108 attenuates renal fibrosis in chronic kidney disease

Renal fibrosis, a common feature of chronic kidney disease (CKD), is characterized by excessive deposition of extracellular matrix (ECM) leading to scar formation in the renal parenchyma. Active epithelial-mesenchymal communication (EMC), and the proliferation and activation of fibroblasts are implicated in the causation of renal fibrosis. Aurora-A kinase (AURKA) is a serine/threonine kinase required for the process of mitosis. Dysregulation of AURKA has been demonstrated in the context of various cancers. However, the role of AURKA in CKD-associated fibrosis has not been elucidated. MK-5108, a potent and highly selective AURKA inhibitor, was shown to exhibit anti-cancer activity in recent preclinical and clinical studies. In the present study, we investigated the role of MK-5108 in renal fibrosis employing animal and cell models. In vivo, AURKA was highly expressed in fibrotic kidneys of CKD patients and in mouse kidneys with unilateral ureteral obstruction (UUO). Post treatment with MK-5108 at the 3rd day after UUO remarkably alleviated renal fibrosis, possibly by inhibiting the proliferation and activation of fibroblasts and suppressing the phenotypic transition of renal cells. Moreover, the enhanced inflammatory factors in obstructive kidneys were also repressed. In vitro, MK-5108 treatment inhibited the pro-fibrotic response in renal cells induced by transforming growth factor-β1. Finally, overexpression of AURKA in renal fibroblasts promoted fibrotic response, while silencing AURKA showed anti-fibrotic effect, further confirming the pro-fibrotic role of AURKA. In this study, inhibition of AURKA by MK-5108 markedly attenuated renal fibrosis. MK-5108 is a potential therapeutic agent for treatment of renal fibrosis in CKD.

Weighted Gene Co-Expression Network Analysis Identifies Five Hub Genes Associated with Metastasis in Synovial Sarcoma

BACKGROUND

Synovial sarcoma (SS) refers to a malignant soft tissue sarcoma (STS) which often occurs in children and adults and has a poor prognosis in elderly patients. Patients with local lesions can be treated with extensive surgical resection combined with adjuvant or radiotherapy, whereas about half of the cases have recurrent diseases and metastatic lesions, and five-year survival ratio is assessed within the range of 27% - 55% only.

METHOD

We downloaded a set of expression profile data (GSE40021) related to SS metastasis based on the Gene Expression Omnibus (GEO) database, and selected distinctly represented genes (DEGs) related to tumor metastasis. WGCNA was used to emphasize the DEGs related to tumor metastasis and obtain co-expression modules. Then, the module most related to SS metastasis was screened out. The genes enriched in this module were analyzed by Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway improvement analysis. Cytoscape software was used for constructing protein-protein interaction (PPI) networks, and hub genes were screened in Oncomine analysis.

RESULT

We selected 514 DEGs, consisting of 210 up-regulated genes and 304 down-regulated genes. Through WGCAN, we got seven co-expression modules and the module most related to SS metastasis was the turquoise module, which contained 66 genes. Finally, we screened out five hub genes (HJURP, NCAPG, TPX2, CENPA, NDC80) through CytoHubba and Oncomine analysis.

CONCLUSION

In this study, we screened five hub genes that may help in clinical diagnosis and serve as the latent purpose of SS treatment.

Targeting AURKA in Cancer: molecular mechanisms and opportunities for Cancer therapy

Aurora kinase A (AURKA) belongs to the family of serine/threonine kinases, whose activation is necessary for cell division processes via regulation of mitosis. AURKA shows significantly higher expression in cancer tissues than in normal control tissues for multiple tumor types according to the TCGA database. Activation of AURKA has been demonstrated to play an important role in a wide range of cancers, and numerous AURKA substrates have been identified. AURKA-mediated phosphorylation can regulate the functions of AURKA substrates, some of which are mitosis regulators, tumor suppressors or oncogenes. In addition, enrichment of AURKA-interacting proteins with KEGG pathway and GO analysis have demonstrated that these proteins are involved in classic oncogenic pathways. All of this evidence favors the idea of AURKA as a target for cancer therapy, and some small molecules targeting AURKA have been discovered. These AURKA inhibitors (AKIs) have been tested in preclinical studies, and some of them have been subjected to clinical trials as monotherapies or in combination with classic chemotherapy or other targeted therapies.

Molecular differential diagnosis of uterine leiomyomas and leiomyosarcomas

Uterine leiomyomas (LM) and leiomyosarcomas (LMS) are considered biologically unrelated tumors due to their cytogenetic and molecular disparity. Yet, these tumors share morphological and molecular characteristics that cannot be differentiated through current clinical diagnostic tests, and thus cannot be definitively classified as benign or malignant until surgery. Newer approaches are needed for the identification of these tumors, as has been done for other tissues. The application of next generation sequencing enables the detection of new mutations that, when coupled to machine learning bioinformatic tools, advances our understanding of chromosomal instability. These approaches in the context of LM and LMS could allow the discovery of genetic variants and possible genomic markers. Additionally, the potential clinical utility of circulating cell-free tumor DNA could revolutionize the noninvasive detection and monitoring of these tumors. Here, we seek to provide a perspective on the molecular background of LM and LMS, recognizing their distinct molecular features that may lead to improved diagnosis and personalized treatments, which would have a measurable impact on women's reproductive health.

The critical role of dysregulated Hh-FOXM1-TPX2 signaling in human hepatocellular carcinoma cell proliferation

Background

Aberrant activation of the Hedgehog (Hh) signaling pathway is frequently observed in hepatocellular carcinoma (HCC), nevertheless, the precise molecular mechanism remains unclear. Forkhead box M1 (FOXM1), a target of the Hh pathway, is a key oncofetal transcription factor and a master cell cycle regulator. Targeting protein for Xenopus kinesin-like protein 2 (TPX2) is an oncogene critical for mitosis. However, how these molecular events affect HCC progression remains unclear.

Methods

Realtime PCR, immunohistochemistry, western blotting, and analyses of datasets TCGA and Gene Expression Omnibus (GEO) were conducted to assess the expression of TPX2 and FOXM1 at the mRNA and protein levels in HCC samples or HCC cells. Expression and knockdown of TPX2 and FOXM1 were performed to assess their role in regulating HCC cell proliferation in vitro and in vivo. Dual luciferase report assay and chromosome immunoprecipitation (ChIP) were investigated to seek the FOXM1 binding sites in the promoter of TPX2.

Results

Specific antagonists (cyclopamine and GANT61) of the Hh pathway down-regulated TPX2, whereas activation of Hh signaling stimulated TPX2 expression. Furthermore, TPX2 over-expression accelerated HCC cell proliferation when upstream events of Hh signaling were inhibited, and TPX2 knockdown significantly alleviated Sonic Hh ligand (Shh)-induced HCC cell proliferation. Reporter assays and ChIP showed that FOXM1 bound to the TPX2 promoter, confirming that TPX2 is a direct downstream target of FOXM1. Xenograft model further verified the cell function and expression regulation of TPX2 and FOXM1 in vivo. Furthermore, FOXM1 regulated TPX2 activity to drive HCC proliferation. Immunohistochemical (IHC) analysis indicated that FOXM1 and TPX2 were highly-expressed in HCC samples and cohort study revealed that FOXM1 and TPX2 may act as negative predictors for the prognosis of patients with HCC.

Conclusions

TPX2 acts as a novel downstream target and effector of the Hh pathway, and Hh signaling contributes to HCC proliferation via regulating the FOXM1-TPX2 cascade, suggesting that this signaling axis may be a novel therapeutic target for HCC.

Graphical abstract

Insights into the non-mitotic functions of Aurora kinase A: more than just cell division

AURKA is a serine/threonine kinase overexpressed in several cancers. Originally identified as a protein with multifaceted roles during mitosis, improvements in quantitative microscopy uncovered several non-mitotic roles as well. In physiological conditions, AURKA regulates cilia disassembly, neurite extension, cell motility, DNA replication and senescence programs. In cancer-like contexts, AURKA actively promotes DNA repair, it acts as a transcription factor, promotes cell migration and invasion, and it localises at mitochondria to regulate mitochondrial dynamics and ATP production. Here we review the non-mitotic roles of AURKA, and its partners outside of cell division. In addition, we give an insight into how structural data and quantitative fluorescence microscopy allowed to understand AURKA activation and its interaction with new substrates, highlighting future developments in fluorescence microscopy needed to better understand AURKA functions in vivo. Last, we will recapitulate the most significant AURKA inhibitors currently in clinical trials, and we will explore how the non-mitotic roles of the kinase may provide new insights to ameliorate current pharmacological strategies against AURKA overexpression.

Role of PLK1 signaling pathway genes in gastrointestinal stromal tumors

In previous studies by the authors, aurora kinase A (AURKA) was demonstrated as an independent poor prognostic marker for the recurrence of localized gastrointestinal stromal tumors (GISTs) and for the progression of advanced GISTs. In the present study, the prognostic effect of genes involved in cell cycle regulation in GISTs was further examined. Leading edge analysis in gene set enrichment analysis was used to identify the most common genes in the top 10 enriched gene sets of high-risk patients with GISTs in a Japanese study. The obtained gene list was uploaded to the Pathway Interaction Database to search for critical pathways. Selected genes within the pathway were subsequently verified through immunohistochemistry (IHC) in another cohort of patients. A total of 5 genes in 'PLK1 signaling events,' namely AURKA, polo-like kinase 1 (PLK1), cell division cycle 25C (CDC25C), budding uninhibited by benzimidazoles (BUB1), and targeting protein for Xklp2 (TPX2), were identified for subsequent study. Among the Japanese cohort, all 5 genes, except BUB1, were significant prognostic factors for poor recurrence-free survival (RFS). Among 141 patients enrolled for the IHC study, all 5 genes exhibited variable expression patterns. In the association study, only AURKA exhibited significant overexpression in non-gastric tumors. Although all 5 genes were considered as risk factors for poor RFS based on a univariate analysis, only the mitotic count and expression levels of CDC25C, BUB1, and TPX2 retained prognostic effects in the multivariate analysis. The PLK1 signaling pathway is crucial in the disease progression of GISTs. Genes within this pathway may serve as predictive markers for adjuvant therapy.

A review of soft-tissue sarcomas: translation of biological advances into treatment measures

Soft-tissue sarcomas are rare malignant tumors arising from connective tissues and have an overall incidence of about five per 100,000 per year. While this diverse family of malignancies comprises over 100 histological subtypes and many molecular aberrations are prevalent within specific sarcomas, very few are therapeutically targeted. Instead of utilizing molecular signatures, first-line sarcoma treatment options are still limited to traditional surgery and chemotherapy, and many of the latter remain largely ineffective and are plagued by disease resistance. Currently, the mechanism of sarcoma oncogenesis remains largely unknown, thus necessitating a better understanding of pathogenesis. Although substantial progress has not occurred with molecularly targeted therapies over the past 30 years, increased knowledge about sarcoma biology could lead to new and more effective treatment strategies to move the field forward. Here, we discuss biological advances in the core molecular determinants in some of the most common soft-tissue sarcomas - liposarcoma, angiosarcoma, leiomyosarcoma, rhabdomyosarcoma, Ewing's sarcoma, and synovial sarcoma - with an emphasis on emerging genomic and molecular pathway targets and immunotherapeutic treatment strategies to combat this confounding disease.

The Aurora kinase A inhibitor TC-A2317 disrupts mitotic progression and inhibits cancer cell proliferation

Mitotic progression is crucial for the maintenance of chromosomal stability. A proper progression is ensured by the activities of multiple kinases. One of these enzymes, the serine/threonine kinase Aurora A, is required for proper mitosis through the regulation of centrosome and spindle assembly. In this study, we functionally characterized a newly developed Aurora kinase A inhibitor, TC-A2317. In human lung cancer cells, TC-A2317 slowed proliferation by causing aberrant formation of centrosome and microtubule spindles and prolonging the duration of mitosis. Abnormal mitotic progression led to accumulation of cells containing micronuclei or multinuclei. Furthermore, TC-A2317–treated cells underwent apoptosis, autophagy or senescence depending on cell type. In addition, TC-A2317 inactivated the spindle assembly checkpoint triggered by paclitaxel, thereby exacerbating mitotic catastrophe. Consistent with this, the expression level of Aurora A in tumors was inversely correlated with survival in lung cancer patients. Collectively, these data suggest that inhibition of Aurora kinase A using TC-A2317 is a promising target for anti-cancer therapeutics.

A Role for Progesterone-Regulated sFRP4 Expression in Uterine Leiomyomas

CONTEXT

Despite progesterone's key role in uterine smooth muscle tumorigenesis, the mechanisms by which it promotes the growth of uterine leiomyomas remain poorly understood.

OBJECTIVE

The aim of this study was to identify gene products mediating the effects of progesterone in uterine leiomyomas.

DESIGN

Gene expression profiling was used to identify putative progesterone-regulated genes differentially expressed in uterine leiomyomas, which were then studied in vitro.

METHODS

Gene expression was comprehensively profiled with the Illumina WG BeadChip (version 2.6) and analyzed with a bioinformatic algorithm that integrates known protein-protein interactions. Genomic binding sites for progesterone receptor (PR) were interrogated by chromatin immunoprecipitation-quantitative polymerase chain reaction (ChIP-qPCR). Small interfering RNA was used to study gene function in primary cell lines.

RESULTS

Our analyses identified secreted Frizzled-related protein 4 (sFRP4) as a key gene product functionally linked to PR activation whose expression was 2.6 times higher in leiomyomas than myometrium (n = 26, P < 0.01) and 2.5 times higher during the proliferative phase of the menstrual cycle (n = 26, P < 0.01). Direct binding between PR and sFRP4 promoter was observed by ChIP-qPCR. Robust overexpression of sFRP4 was also observed in primary cultures derived from leiomyoma. Progesterone preferentially inhibited sFRP4 expression and secretion in leiomyoma cultures in a dose-dependent manner sensitized by estradiol. Knockdown of sFRP4 inhibited proliferation and apoptosis in primary cultures of both myometrium and leiomyoma.

CONCLUSIONS

Overexpression of sFRP4 is a robust, progesterone-regulated feature of leiomyomas that increases smooth muscle proliferation. More work is needed to elucidate how progesterone's ability to modulate sFRP4 expression contributes to uterine smooth muscle tumorigenesis.

Molecular characteristics of uterine sarcomas

INTRODUCTION

Uterine sarcomas are rare cancers, of which the most common entities are leiomyosarcoma and endometrial stromal sarcoma. These two tumors may have overlapping clinical presentation, morphology and immunohistochemical profile, but are increasingly recognized to be two molecularly distinct entities. Endometrial stromal sarcomas are further currently divided into a low-grade and high-grade group based on molecular characteristics. Area covered: This review discusses recent data which shed light on the molecular profile of these two cancers and may aid in understanding their evolution and progression, in the aim of improving their diagnosis and management. Search was through PubMed, with focus on studies published in the last 5 years. Expert commentary: The literature presented and discussed documents rapidly expanding knowledge of the genetic characteristics of leiomyosarcoma and endometrial stromal sarcoma, with an array of molecules and pathways implicated in the biology of these cancers. Several of these molecules are potential therapeutic targets. Assessment of their predictive and prognostic role awaits larger studies.

Uterine leiomyosarcoma: Epidemiology, contemporary treatment strategies and the impact of uterine morcellation

Leiomyosarcoma, a rare tumor subtype, accounts for 1% of all uterine malignancies, but contributes to a significant proportion of uterine cancer deaths. Surgery is considered the mainstay of treatment for all soft tissue sarcomas, including uterine variants. However, uterine leiomyosarcoma is challenging to diagnose preoperatively and can mimic the appearance of benign uterine leiomyomas. Recently, concerns have grown in this regard, as surgeons have utilized uterine morcellation and myomectomy procedures unknowingly in the setting of occult uterine sarcoma. Because of aggressive tumor biology and relative chemotherapy and radiotherapy resistance, efficacious therapies to achieve prolonged survival or cure in those with both early and advanced-stage uterine leiomyosarcoma have been elusive. The strongest determinant of survival remains stage at diagnosis, though prediction models may provide a more accurate prognosis. Given the aggressive nature of this sarcoma subtype, novel early detection strategies and targeted therapies are the focus of several recently published and ongoing studies. While gemcitabine/docetaxel and doxorubicin remain the most active regimens in the treatment of advanced or recurrent disease, currently available cytotoxic regimens remain inadequate, with 5-year disease-specific survival of <30%. Pazopanib, trabectedin and olaratumab, are FDA-approved, targeted therapies with activity in uterine and other leiomyosarcomas, while aromatase inhibitors and immunotherapies are under active investigation. This review provides a critical appraisal of the literature regarding the contemporary surgical and medical management of uterine leiomyosarcoma, the role of targeted therapies, and the implications of uterine morcellation on gynecologic surgical practice.

A phase 2 study of alisertib (MLN8237) in recurrent or persistent uterine leiomyosarcoma: An NRG Oncology/Gynecologic Oncology Group study 0231D

OBJECTIVE

This two-stage Phase II study assessed the activity of single agent alisertib in patients with recurrent/persistent uterine leiomyosarcoma (uLMS).

METHODS

Eligibility criteria included histologically-confirmed, recurrent or persistent uLMS, age≥18, 1-2 prior cytotoxic regimens, and RECIST version 1.1 measurable disease. The primary objective of the study was to evaluate the efficacy of alisertib through the frequency of patients with objective tumor responses and the frequency who survived event-free for at least 6months (EFS6). The endpoints for EFS were RECIST progression, death, or beginning a subsequent therapy. The null hypothesis jointly specified the probability of a patient experiencing a tumor response to less than or equal to 5% and the probability of a patient surviving event-free for at least 6months to less than or equal to 20%. A two-stage design was used with a target accrual of 23 patients for stage 1 and 47 pts. cumulative for stage 2. Confidence intervals do not correct for multiplicity.

RESULTS

Twenty-three patients were enrolled with two patients excluded on central histology review, yielding 21 eligible patients. Median age was 61years. Prior treatment was either 1 cytotoxic regimen (71.4%) or 2 (28.6%). The most common treatment related AEs (grade 3 or worse) were anemia Hensley et al. (2008a) , leukopenia Hensley et al. (2008b) , neutropenia Maki et al. (2007) , thrombocytopenia Huang et al. (2012) , mucositis Hensley et al. (2008a) , diarrhea Huang et al. (2012) , and palmer-planter syndrome Zivanovic et al. (2012) . There were no objective responses (0%; 90% CI: 0-10.4%). Best response was stable disease (38.1%); 12 patients had progressive disease (57.1%). EFS6 was 0% (90% CI: 0-10.4%). Median PFS and OS were 1.7 (90% CI: 1.4-3.2) and 14.5months (90% CI: 7.6 - NA), respectively.

CONCLUSION

Alisertib did not demonstrate clinically meaningful single agent activity in previously treated uLMS.

Molecular Targets and Emerging Therapeutic Options for Uterine Leiomyosarcoma

Uterine leiomyosarcoma (uLMS) is an aggressive malignancy characterized by its early metastasis, high rates of recurrence, and poor prognosis. Multiple obstacles complicate the clinical management of uLMS. These include the fact that most uLMS are typically identified only after a woman has undergone hysterectomy or myomectomy, the limited efficacy of adjuvant therapy for early stage disease, and the poor response of metastatic disease to current treatments. Here, we discuss recent insights into the molecular basis of uLMS and discuss emerging options for its clinical management. Particular attention is given to the biologic basis of these strategies with the goal of understanding the rationale motivating their use.

TOP2A copy number and TOP2A expression in uterine benign smooth muscle tumours and leiomyosarcoma

AIMS

To examine TOP2A copy number, TOP2A expression, and its prognostic value in uterine leiomyosarcoma (LMS) and other benign smooth muscle tumours.

METHODS

We analysed 37 patients treated for uterine LMS with immunohistochemistry for protein expression and fluorescence in situ hybridisation (FISH) for copy number. Twelve cases of leiomyoma variants (LMVs), 4 smooth muscle tumours of uncertain malignant potential (STUMP) and 23 leiomyomas (LMs) were also included.

RESULTS

Eighteen patients with LMS (48.6%) were International Federation of Gynecology and Obstetrics (FIGO) stage I, six (16.2%) were stage II, four (10.8%) were stage III, and nine (24.3%) were stage IV. Twenty-one (56.8%) patients with LMS showed high expression of TOP2A. Greater TOP2A levels were found in patients with stage ≥II disease compared with stage I and also in high mitotic index tumours (>20/10 HPF (high power field)). Eleven (36.7%) cases had abnormal TOP2A copy numbers. There was no link between TOP2A copy number and TOP2A expression. All patients with benign smooth muscle tumours had low TOP2A immunohistochemical expression and one (7.7%) patient had TOP2A amplification. TOP2A expression and TOP2A copy number had no impact on disease outcomes. Only the presence of disease outside of the uterus negatively impacted survival compared with early disease (53.4 vs 15.8 months; p<0.001).

CONCLUSIONS

TOP2A is highly expressed in advanced LMS but not in non-malignant diseases. TOP2A expression does not correlate with FISH results and does not predict outcome. TOP2A levels are higher in high-mitotic index tumours and in more advanced stages of disease.

Increased Expression of Phosphorylated Polo-Like Kinase 1 and Histone in Bypass Vein Graft and Coronary Arteries following Angioplasty

Interventional procedures, including percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass surgery (CABG) to re-vascularize occluded coronary arteries, injure the vascular wall and cause endothelial denudation and medial vascular smooth muscle cell (VSMCs) metaplasia. Proliferation of the phenotypically altered SMCs is the key event in the pathogenesis of intimal hyperplasia (IH). Several kinases and phosphatases regulate cell cycle in SMC proliferation. It is our hypothesis that increased expression and activity of polo-like kinase-1 (PLK1) in SMCs, following PTCA and CABG, contributes to greater SMC proliferation in the injured than uninjured blood vessels. Using immunofluorescence (IF), we assessed the expression of PLK1 and phosphorylated-PLK1 (pPLK1) in post-PTCA coronary arteries, and superficial epigastric vein grafts (SEV) and compared it with those in the corresponding uninjured vessels. We also compared the expressions of mitotic marker phospho-histone, synthetic-SMC marker, contractile SMC marker, IFN-γ and phosphorylated STAT-3 in the post-PTCA arteries, SEV-grafts, and the uninjured vessels. Immunostaining demonstrated an increase in the number of cells expressing PLK1 and pPLK1 in the neointima of post PTCA-coronary arteries and SEV-grafts compared to their uninjured counterparts. VSMCs in the neointima showed an increased expression of phospho-histone, synthetic and contractile SMC markers, IFN-γ and phosphorylated STAT-3. However, VSMCs of uninjured coronaries and SEV had no significant expression of the aforementioned proteins. These data suggest that PLK1 might play a critical role in VSMC mitosis in hyperplastic intima of the injured vessels. Thus, novel therapies to inhibit PLK1 could be developed to inhibit the mitogenesis of VSMCs and control neointimal hyperplasia.

Molecular subtypes of uterine leiomyosarcoma and correlation with clinical outcome

The molecular etiology of uterine leiomyosarcoma (ULMS) is poorly understood, which accounts for the wide disparity in outcomes among women with this disease. We examined and compared the molecular profiles of ULMS and normal myometrium (NL) to identify clinically relevant molecular subtypes. Discovery cases included 29 NL and 23 ULMS specimens. RNA was hybridized to Affymetrix U133A 2.0 transcription microarrays. Differentially expressed genes and pathways were identified using standard methods. Fourteen NL and 44 ULMS independent archival samples were used for external validation. Molecular subgroups were correlated with clinical outcome. Pathway analyses of differentially expressed genes between ULMS and NL samples identified overrepresentation of cell cycle regulation, DNA repair, and genomic integrity. External validation confirmed differential expression in 31 genes (P < 4.4 × 10(-4), Bonferroni corrected), with 84% of the overexpressed genes, including CDC7, CDC20, GTSE1, CCNA2, CCNB1, and CCNB2, participating in cell cycle regulation. Unsupervised clustering of ULMS identified two clades that were reproducibly associated with progression-free (median, 4.0 vs 26.0 months; P = .02; HR, 0.33) and overall (median, 18.2 vs 77.2 months; P = .04; HR, 0.33) survival. Cell cycle genes play a key role in ULMS sarcomagenesis, providing opportunities for therapeutic targeting. Reproducible molecular subtypes associated with clinical outcome may permit individualized adjuvant treatment after clinical trial validation.

Potential Therapeutic Targets in Uterine Sarcomas

Uterine sarcomas are rare tumors accounting for 3,4% of all uterine cancers. Even after radical hysterectomy, most patients relapse or present with distant metastases. The very limited clinical benefit of adjuvant cytotoxic treatments is reflected by high mortality rates, emphasizing the need for new treatment strategies. This review summarizes rising potential targets in four distinct subtypes of uterine sarcomas: leiomyosarcoma, low-grade and high-grade endometrial stromal sarcoma, and undifferentiated uterine sarcoma. Based on clinical reports, promising approaches for uterine leiomyosarcoma patients include inhibition of VEGF and mTOR signaling, preferably in combination with other targeted or cytotoxic compounds. Currently, the only targeted therapy approved in leiomyosarcoma patients is pazopanib, a multitargeted inhibitor blocking VEGFR, PDGFR, FGFR, and c-KIT. Additionally, preclinical evidence suggests effect of the inhibition of histone deacetylases, tyrosine kinase receptors, and the mitotic checkpoint protein aurora kinase A. In low-grade endometrial stromal sarcomas, antihormonal therapies including aromatase inhibitors and progestins have proven activity. Other potential targets are PDGFR, VEGFR, and histone deacetylases. In high-grade ESS that carry the YWHAE/FAM22A/B fusion gene, the generated 14-3-3 oncoprotein is a putative target, next to c-KIT and the Wnt pathway. The observation of heterogeneity within uterine sarcoma subtypes warrants a personalized treatment approach.

3D-QSAR (CoMFA, CoMFA-RG, CoMSIA) and molecular docking study of thienopyrimidine and thienopyridine derivatives to explore structural requirements for aurora-B kinase inhibition

Aurora-B kinase plays a crucial role in cell cycle events and is identified as an important factor in regulation of spindle check point assembly. Thus, it can be proved as an important target in the field of oncology. 3D-QSAR model was generated using 54 molecules reported in literature containing thienopyrimidine and thienopyridine as scaffolds. All molecules were aligned using Distill function in Sybyl X1.2. This generated best model of CoMFA-RG (Region focusing) and CoMSIA were statistically significant with correlation coefficient r(2)ncv of 0.97, for both & Leave one out coefficient (LOO) q(2) of 0.70 and 0.72, respectively. Best CoMSIA model was built up using various combination of descriptors and proved statistical significant among all models. Best CoMFA-RG and CoMSIA models were validated by 12 test set molecules giving satisfactory prediction (r(2)pred) values of 0.86 and 0.88, respectively. External test set validation was performed using 20 molecules and satisfactory prediction of their biological activity was found. Active compounds were docked on protein (PDB ID: 4C2V) by GOLD module and revealed important interactions with amino acids at ATP-binding region. These data explored insight requirements for Aurora-B inhibition which might be fruitful for understanding mechanisms with kinase ligand interactions.

The importance of being dead: cell death mechanisms assessment in anti-sarcoma therapy

Cell death can occur through different mechanisms, defined by their nature and physiological implications. Correct assessment of cell death is crucial for cancer therapy success. Sarcomas are a large and diverse group of neoplasias from mesenchymal origin. Among cell death types, apoptosis is by far the most studied in sarcomas. Albeit very promising in other fields, regulated necrosis and other cell death circumstances (as so-called "autophagic cell death" or "mitotic catastrophe") have not been yet properly addressed in sarcomas. Cell death is usually quantified in sarcomas by unspecific assays and in most cases the precise sequence of events remains poorly characterized. In this review, our main objective is to put into context the most recent sarcoma cell death findings in the more general landscape of different cell death modalities.

Management of advanced uterine leiomyosarcoma

PURPOSE OF REVIEW

The purpose of this article is to review current evidence-based management strategies for patients with recurrent and metastatic uterine leiomyosarcoma (LMS). We will focus on treatment of advanced multifocal disease as well as new developments in targeted cancer therapies.

RECENT FINDINGS

The management of patients with advanced uterine LMS is divided between those with localized and those with disseminated disease. Selected patients with localized or single-organ oligometastatic disease may benefit from surgical resection. For patients with disseminated disease, fixed-dose-rate gemcitabine plus docetaxel is an appropriate first-line chemotherapy regimen. Other active cytotoxic agents include doxorubicin, ifosfamide, and dacarbazine. The role of trabectedin (approved by the European Medicine Agency to be marketed for advanced or metastatic soft tissue sarcoma) is being explored. Trials are also underway for targeted therapy in uterine LMS. Currently, the only approved targeted therapy for advanced soft tissue sarcoma is pazopanib. In patients with small volume and slowly progressive estrogen receptor/progesterone receptor-positive disease, antiestrogen therapy with an aromatase inhibitor is a reasonable alternative to observation alone.

SUMMARY

Despite recent advances, overall survival for advanced disease remains poor and identification of novel agents with activity in LMS is clearly needed.

Pharmacological treatment for uterine leiomyosarcomas

INTRODUCTION

Pharmacological treatment plays a major role in the management of advanced, persistent or recurrent uterine leiomyosarcoma (LMS), whereas its usefulness in the adjuvant setting is still debated. A thorough literature search was undertaken using the Pubmed databases. Systematic reviews and controlled trials on medical treatment of uterine LMS were collected and critically analyzed. Other study types were secondarily considered when pertinent.

AREAS COVERED

Doxorubicin (DOX), ifosfamide and dacarbazine have been long used in the treatment of this malignancy. Novel active agents are represented by gemcitabine, docetaxel, trabectedin, pazopanib and aromatase inhibitors, whereas the role of eribulin, bevacizumab, aflibercept and mammalian target of rapamycin inhibitors is still investigational.

EXPERT OPINION

DOX alone, gemcitabine alone, DOX + dacarbazine and gemcitabine + docetaxel may be treatment options for first-line and second-line therapies. However, the clinical benefit of the combination chemotherapy versus single-agent chemotherapy is still debated. Trabectedin is a promising agent for recurrent uterine LMS, able to obtain a prolonged disease control, with 3-month and 6-month progression-free survival rates exceeding 50 and 30%, respectively, and with sometimes unexpectedly durable responses. Pazopanib is the only approved targeted therapy. Hormone therapy with aromatase inhibitors may be a therapeutic option in heavily treated patients with slowly progressive, steroid receptor-positive tumors. Whenever possible, women with recurrent uterine LMS should be encouraged to enter well-designed clinical trials aimed to detect novel active agents.

TPX2: of spindle assembly, DNA damage response, and cancer

For more than 15 years, TPX2 has been studied as a factor critical for mitosis and spindle assembly. These functions of TPX2 are attributed to its Ran-regulated microtubule-associated protein properties and to its control of the Aurora A kinase. Overexpressed in cancers, TPX2 is being established as marker for the diagnosis and prognosis of malignancies. During interphase, TPX2 resides preferentially in the nucleus where its function had remained elusive until recently. The latest finding that TPX2 plays a role in amplification of the DNA damage response, combined with the characterization of TPX2 knockout mice, open new perspectives to understand the biology of this protein. This review provides an historic overview of the discovery of TPX2 and summarizes its cytoskeletal and signaling roles with relevance to cancer therapies. Finally, the review aims to reconcile discrepancies between the experimental and pathological effects of TPX2 overexpression and advances new roles for compartmentalized TPX2.

Coregulation of FANCA and BRCA1 in human cells

Fanconi anemia (FA) is a genetically heterogeneous syndrome associated with increased cancer predisposition. The underlying genes govern the FA pathway which functions to protect the genome during the S-phase of the cell cycle. While upregulation of FA genes has been linked to chemotherapy resistance, little is known about their regulation in response to proliferative stimuli. The purpose of this study was to examine how FA genes are regulated, especially in relation to the cell cycle, in order to reveal their possible participation in biochemical networks. Expression of 14 FA genes was monitored in two human cell-cycle models and in two RB1/E2F pathway-associated primary cancers, retinoblastoma and basal breast cancer. In silico studies were performed to further evaluate coregulation and identify connected networks and diseases. Only FANCA was consistently induced over 2-fold; FANCF failed to exhibit any regulatory fluctuations. Two tools exploiting public data sets indicated coregulation of FANCA with BRCA1. Upregulation of FANCA and BRCA1 correlated with upregulation of E2F3. Genes coregulated with both FANCA and BRCA1 were enriched for MeSH-Term id(s) genomic instability, microcephaly, and Bloom syndrome, and enriched for the cellular component centrosome. The regulation of FA genes appears highly divergent. In RB1-linked tumors, upregulation of FA network genes was associated with reduced expression of FANCF. FANCA and BRCA1 may jointly act in a subnetwork - supporting vital function(s) at the subcellular level (centrosome) as well as at the level of embryonic development (mechanisms controlling head circumference).

Epigenetic Regulators: New Therapeutic Targets for Soft Tissue Sarcoma

Soft tissue sarcoma is a malignancy that develops from human soft tissues such as muscle, nerve, fat, and blood vessels. The World Health Organization classification comprises about 50 different histologic types of soft tissue sarcoma. Soft tissue sarcoma is treated most often with surgery. Chemotherapy and radiotherapy have shown only minor effects on patient survival in this disease. The overall 5-year survival rate of soft tissue sarcoma is 50%; it has not changed for the past several decades. A new class of therapeutic targets for soft tissue sarcoma was identified recently. Epigenetic regulators, such as DNA methyltransferases, histone deacetylases, and histone-modifying enzyme enhancer of zeste homolog 2, have been found to be involved in pathogenesis of various soft tissue sarcomas. Small-molecule inhibitors of these epigenetic regulators may provide a new targeted therapy approach to soft tissue sarcomas in the future.

Identification of aurora kinase A as an unfavorable prognostic factor and potential treatment target for metastatic gastrointestinal stromal tumors

Although imatinib mesylate (IM) has revolutionized the management of gastrointestinal stromal tumors (GISTs), drug resistance remains a challenge. Previous studies have shown that the expression of aurora kinase A (AURKA) predicts recurrence in patients with primary, surgically resected GISTs. The current study aimed to evaluate the significance of AURKA expression as an unfavorable prognostic marker for advanced GISTs, and provide evidence that AURKA could be a potential therapeutic target in GISTs. The prognostic significance of the expression of AURKA, along with other clinicopathological factors, was analyzed in a cohort of 99 IM-treated patients with advanced GISTs. The potential use of an inhibitor of AURKA as a therapeutic agent against GISTs was also tested in GIST cell lines. Among 99 enrolled patients, poor performance status, large tumor size, drug response, and AURKA overexpression were independent prognostic factors for poor progression-free survival (PFS). For overall survival (OS), only large tumor size and AURKA overexpression were identified as independent unfavorable factors. In an in vitro study, MLN8237, an AURKA inhibitor, inhibited growth of both IM-sensitive and IM-resistant GIST cells in a concentration-dependent manner, and exhibited synergistic cytotoxicity with IM in GIST cells. The inhibitory effect of MLN8237 in GIST cells could be attributed to the induction of G2/M arrest, apoptosis, and senescence. Our study shows that AURKA expression independently predicted poor PFS and OS in patients with advanced GISTs who were treated with IM. An AURKA inhibitor may have potential as a therapeutic agent for both IM-sensitive and IM-resistant GISTs.

Aurora kinase inhibitor patents and agents in clinical testing: an update (2011 - 2013)

INTRODUCTION

Aurora kinase A, B and C, members of serine/threonine kinase family, are key regulators of mitosis. As Aurora kinases are overexpressed in many of the human cancers, small-molecule inhibitors of Aurora kinase have emerged as a possible treatment option for cancer.

AREAS COVERED

In 2009 and 2011, the literature pertaining to Aurora kinase inhibitors and their patents was reviewed. Here, the aim is to update the information for Aurora kinase inhibitors in clinical trials and the patents filed between the years 2011 and 2013. Pubmed, Scopus®, Scifinder®, USPTO, EPO and www.clinicaltrials.gov databases were used for searching the literature and patents for Aurora kinase inhibitors.

EXPERT OPINION

Even though both Aurora sub-type selective as well as pan-selective inhibitors show preclinical and clinical efficacy, so far no Aurora kinase inhibitor has been approved for clinical use. Particularly, dose-limiting toxicity (neutropenia) is a key issue that needs to be addressed. Preliminary evidence suggests that the use of selective Aurora A inhibitors could avoid Aurora B-mediated neutropenia in clinical settings. Also, use of adjunctive agents such as granulocyte stimulating factor to overcome neutropenia associated with Aurora B inhibition could be an answer to overcome the toxicity and bring Aurora inhibitors to market in the future.

Therapeutic targeting of Polo-like kinase-1 and Aurora kinases in T-cell acute lymphoblastic leukemia

Polo-like kinases (PLKs) and Aurora kinases (AKs) act as key cell cycle regulators in healthy human cells. In cancer, these protein kinases are often overexpressed and dysregulated, thus contributing to uncontrolled cell proliferation and growth. T-cell acute lymphoblastic leukemia (T-ALL) is a heterogeneous malignancy arising in the thymus from T-cell progenitors. Primary chemoresistant and relapsed T-ALL patients have yet a poor outcome, therefore novel therapies, targeting signaling pathways important for leukemic cell proliferation, are required. Here, we demonstrate the potential therapeutic effects of BI6727, MK-5108, and GSK1070916, three selective inhibitors of PLK1, AK-A, and AK-B/C, respectively, in a panel of T-ALL cell lines and primary cells from T-ALL patients. The drugs were both cytostatic and cytotoxic to T-ALL cells by inducing G2/M-phase arrest and apoptosis. The drugs retained part of their pro-apoptotic activity in the presence of MS-5 bone marrow stromal cells. Moreover, we document for the first time that BI6727 perturbed both the PI3K/Akt/mTORC2 and the MEK/ERK/mTORC1 signaling pathways, and that a combination of BI6727 with specific inhibitors of the aforementioned pathways (MK-2206, CCI-779) displayed significantly synergistic cytotoxic effects. Taken together, our findings indicate that PLK1 and AK inhibitors display the potential for being employed in innovative therapeutic strategies for improving T-ALL patient outcome.

Molecular profiling of soft tissue sarcomas using next-generation sequencing: a pilot study toward precision therapeutics

Next-generation sequencing (NGS) can provide in-depth detection of numerous gene alterations. To date, there are very few reports describing the use of this technique in soft tissue sarcomas. Herein, we aim to test the utility of NGS in identifying targetable mutations in these tumors. NGS was performed using a clinically validated multiplexed gene sequencing panel interrogating the full coding sequence of 194 cancer-related genes. A custom bioinformatics pipeline was developed to detect all classes of mutations directly from the NGS data, including single-nucleotide variants, small insertions and deletions, copy number variation, and complex structural variations. Twenty-five soft tissue sarcomas were analyzed; 18 of these patients had metastatic disease and 7 primary locally advanced tumors. Targetable mutations for which clinical trials are available were identified in 60% of the cases. MAP2K4, AURKA, AURKB, and c-MYC amplification were recurrent events in leiomyosarcomas. Frequent non-targetable variants included copy losses of the TP53 (24%), PTEN (16%), and CDKN2A (20%). Additional frameshift mutations, deletion mutations, and single-nucleotide variants involving numerous genes, including RB1, NOTCH1, PIK3CA, PDGFRB, EPHA5, KDM6A, NF1, and FLT4 genes, were also identified. NGS is useful in identifying targetable mutations in soft tissue sarcomas that can serve as a rationale for inclusion of patients with advanced disease in ongoing clinical trials and allow for better risk stratification.

Anticancer activity of the Aurora A kinase inhibitor MK-5108 in non-small-cell lung cancer (NSCLC) in vitro as monotherapy and in combination with chemotherapies

PURPOSE

Aurora kinases are key regulators of mitotic events. Dysfunction of these kinases can cause polyploidy and chromosomal instability, a contributor to tumorigenesis. MK-5108 is a potent inhibitor of Aurora A kinase that has shown preclinical potent activity in malignancies of breast, cervical, colon, ovarian, and pancreatic origin. We sought to assess the preclinical efficacy of MK-5108 in a panel of non-small-cell lung cancer cell lines as a single agent and in combination with cisplatin and docetaxel.

METHODS

Eleven lung cancer cell lines were studied. Growth inhibition by MK-5108 was assessed with short- and long-term MTT assays. Cell cycling was measured by flow cytometry. Immunoblotting was used to determine targeted activity of MK-5108 on Aurora A and downstream effects (TACC3 and Plk1). Efficacy of combination studies performed with cisplatin and docetaxel was evaluated by median effect analysis.

RESULTS

All cell lines demonstrated sustained growth inhibition following MK-5108 at varying nanomolar concentrations. MK-5108 induced G2/M accumulation, polyploidy, and apoptosis (increased sub-G1/PARP cleavage). Levels of Aurora A, TACC3, and Plk1 diminished. Concurrent treatment of MK-5108 with cisplatin or docetaxel synergistically inhibited cell growth with the docetaxel combination performing better. When administered sequentially, treatment with docetaxel first followed by MK-5108 exhibited greater growth inhibition than the inverse; yet concurrent treatment remained superior.

CONCLUSIONS

MK-5108 has potent anti-proliferative activity in lung cancer cell lines alone and in combination with chemotherapies. Determining how best to integrate Aurora inhibitors into current lung cancer treatment regimens would be beneficial.

Multimodal effects of small molecule ROCK and LIMK inhibitors on mitosis, and their implication as anti-leukemia agents

Accurate chromosome segregation is vital for cell viability. Many cancer cells show chromosome instability (CIN) due to aberrant expression of the genes involved in chromosome segregation. The induction of massive chromosome segregation errors in such cancer cells by small molecule inhibitors is an emerging strategy to kill these cells selectively. Here we screened and characterized small molecule inhibitors which cause mitotic chromosome segregation errors to target cancer cell growth. We screened about 300 chemicals with known targets, and found that Rho-associated coiled-coil kinase (ROCK) inhibitors bypassed the spindle assembly checkpoint (SAC), which delays anaphase onset until proper kinetochore-microtubule interactions are established. We investigated how ROCK inhibitors affect chromosome segregation, and found that they induced microtubule-dependent centrosome fragmentation. Knockdown of ROCK1 and ROCK2 revealed their additive roles in centrosome integrity. Pharmacological inhibition of LIMK also induced centrosome fragmentation similar to that by ROCK inhibitors. Inhibition of ROCK or LIMK hyper-stabilized mitotic spindles and impaired Aurora-A activation. These results suggested that ROCK and LIMK are directly or indirectly involved in microtubule dynamics and activation of Aurora-A. Furthermore, inhibition of ROCK or LIMK suppressed T cell leukemia growth in vitro, but not peripheral blood mononuclear cells. They induced centrosome fragmentation and apoptosis in T cell leukemia cells. These results suggested that ROCK and LIMK can be a potential target for anti-cancer drugs.

Recent developments in uterine mesenchymal neoplasms

Smooth muscle and endometrial stromal tumours represent the two most common uterine mesenchymal neoplasms that may present diagnostic dilemmas for the practising surgical pathologist. Recent changes in morphological and staging criteria, as well as the discovery of new immunohistochemical markers, have improved the diagnosis and classification of these tumours. We highlight the difficulty in distinguishing tumour cell necrosis from infarct-type necrosis and the limited utility of p16 immunohistochemical expression in the diagnosis of leiomyosarcoma. We also discuss the controversial use of mitotic activity and necrosis as prognostic factors in endometrial stromal sarcomas. Emerging genetic information has also greatly expanded our understanding of 'sarcomagenesis' in both tumour types and may provide insight into potential therapeutic targets for the treatment of leiomyosarcoma and endometrial stromal sarcomas, harboring MED12 (mediator complex subunit 12) mutations and recurrent gene rearrangements, respectively. In this review, we discuss the core updates in the diagnosis and classification of uterine leiomyosarcomas and endometrial stromal sarcomas, highlighting new and important molecular genetic findings that may drive pathogenesis.

Dual targeting of mTOR and aurora-A kinase for the treatment of uterine Leiomyosarcoma

PURPOSE

The significance of mTOR activation in uterine leiomyosarcoma (ULMS) and its potential as a therapeutic target were investigated. Furthermore, given that effective therapies likely require combination mTOR blockade with inhibition of other targets, coupled with recent observations suggesting that Aurora-A kinase (Aurk-A) deregulations commonly occur in ULMS, the preclinical impact of dually targeting both pathways was evaluated.

EXPERIMENTAL DESIGN

Immunohistochemical staining was used to evaluate expression of activated mTOR components in a large (>200 samples) ULMS tissue microarray. Effects of mTOR blockade (using rapamycin) and Aurk-A inhibition (using MLN8237) alone and in combination on human ULMS cell growth, cell-cycle progression, and apoptosis were assessed in cellular assays. Drug interactions were determined via combination index analyses. The antitumor effects of inhibitors alone or in combination were evaluated in vivo.

RESULTS

Enhanced mTOR activation was seen in human ULMS samples. Increased pS6RP and p4EBP1 expression correlated with disease progression; p4EBP1 was found to be an independent prognosticator of patient outcome. Rapamycin inhibited growth and cell-cycle progression of ULMS cell strains/lines in culture. However, only a cytostatic effect on tumor growth was found in vivo. Combining rapamycin with MLN8237 profoundly (and synergistically) abrogated ULMS cells' growth in culture; interestingly, these effects were seen only when MLN8237 was preadministered. This novel therapeutic combination and scheduling regimen resulted in marked tumor growth inhibition in vivo.

CONCLUSIONS

mTOR and Aurk-A pathways are commonly deregulated in ULMS. Preclinical data support further exploration of dual mTOR and Aurk-A therapeutic blockade for human ULMS.