Comprehensive analysis of the ErbB receptor family in pediatric nervous system tumors and rhabdomyosarcoma.

BACKGROUND: There is a paucity of knowledge regarding pediatric biomarkers, including the relevance of ErbB pathway aberrations in pediatric tumors. We investigated the occurrence of ErbB receptor aberrations across different pediatric malignancies, to identify patterns of ErbB dysregulation and define biomarkers suitable for patient enrichment in clinical studies. PROCEDURE: Tissue samples from 297 patients with nervous system tumors and rhabdomyosarcoma were analyzed for immunohistochemical expression or gene amplification of epidermal growth factor receptor (EGFR) and human epidermal growth factor receptor 2 (HER2). Exploratory analyses of HER3/HER4 expression, and mRNA expression of ErbB receptors/ligands (NanoString) were performed. Assay validation followed general procedures, with additional validation to address Clinical Laboratory Improvement Amendments (CLIA) requirements. RESULTS: In most tumor types, samples with high ErbB receptor expression were found with heterogeneous distribution. We considered increased/aberrant ErbB pathway activation when greater than or equal to two EGFR/HER2 markers were simultaneously upregulated. ErbB pathway dysregulation was identified in ∼20%-30% of samples for most tumor types (medulloblastoma/primitive neuroectodermal tumors 31.1%, high-grade glioma 27.1%, neuroblastoma 22.7%, rhabdomyosarcoma 23.1%, ependymoma 18.8%), 4.2% of diffuse intrinsic pontine gliomas, and no recurrent or refractory low-grade astrocytomas. In medulloblastoma/primitive neuroectodermal tumors and neuroblastoma, this was attributed mainly to high EGFR polysomy/HER2 amplification, whereas EGFR gene amplification was observed in some high-grade glioma samples. EGFR/HER2 overexpression was most prevalent in ependymoma. CONCLUSIONS: Overexpression and/or amplification of EGFR/HER2 were identified as potential enrichment biomarkers for clinical trials of ErbB-targeted drugs.

Triple Angiokinase Inhibitor Nintedanib Directly Inhibits Tumor Cell Growth and Induces Tumor Shrinkage via Blocking Oncogenic Receptor Tyrosine Kinases.

The triple-angiokinase inhibitor nintedanib is an orally available, potent, and selective inhibitor of tumor angiogenesis by blocking the tyrosine kinase activities of vascular endothelial growth factor receptor (VEGFR) 1-3, platelet-derived growth factor receptor (PDGFR)-α and -ß, and fibroblast growth factor receptor (FGFR) 1-3. Nintedanib has received regulatory approval as second-line treatment of adenocarcinoma non-small cell lung cancer (NSCLC), in combination with docetaxel. In addition, nintedanib has been approved for the treatment of idiopathic lung fibrosis. Here we report the results from a broad kinase screen that identified additional kinases as targets for nintedanib in the low nanomolar range. Several of these kinases are known to be mutated or overexpressed and are involved in tumor development (discoidin domain receptor family, member 1 and 2, tropomyosin receptor kinase A (TRKA) and C, rearranged during transfection proto-oncogene [RET proto oncogene]), as well as in fibrotic diseases (e.g., DDRs). In tumor cell lines displaying molecular alterations in potential nintedanib targets, the inhibitor demonstrates direct antiproliferative effects: in the NSCLC cell line NCI-H1703 carrying a PDGFRα amplification (ampl.); the gastric cancer cell line KatoIII and the breast cancer cell line MFM223, both driven by a FGFR2 amplification; AN3CA (endometrial carcinoma) bearing a mutated FGFR2; the acute myeloid leukemia cell lines MOLM-13 and MV-4-11-B with FLT3 mutations; and the NSCLC adenocarcinoma LC-2/ad harboring a CCDC6-RET fusion. Potent kinase inhibition does not, however, strictly translate into antiproliferative activity, as demonstrated in the TRKA-dependent cell lines CUTO-3 and KM-12. Importantly, nintedanib treatment of NCI-H1703 tumor xenografts triggered effective tumor shrinkage, indicating a direct effect on the tumor cells in addition to the antiangiogenic effect on the tumor stroma. These findings will be instructive in guiding future genome-based clinical trials of nintedanib.

Efficacy and mechanism of action of volasertib, a potent and selective inhibitor of Polo-like kinases, in preclinical models of acute myeloid leukemia.

Polo-like kinase 1 (Plk1), a member of the Polo-like kinase family of serine/threonine kinases, is a key regulator of multiple steps in mitosis. Here we report on the pharmacological profile of volasertib, a potent and selective Plk inhibitor, in multiple preclinical models of acute myeloid leukemia (AML) including established cell lines, bone marrow samples from AML patients in short-term culture, and subcutaneous as well as disseminated in vivo models in immune-deficient mice. Our results indicate that volasertib is highly efficacious as a single agent and in combination with established and emerging AML drugs, including the antimetabolite cytarabine, hypomethylating agents (decitabine, azacitidine), and quizartinib, a signal transduction inhibitor targeting FLT3. Collectively, these preclinical data support the use of volasertib as a new therapeutic approach for the treatment of AML patients, and provide a foundation for combination approaches that may further improve and prolong clinical responses.

A randomized, open-label, phase I/II trial to investigate the maximum tolerated dose of the Polo-like kinase inhibitor BI 2536 in elderly patients with refractory/relapsed acute myeloid leukaemia.

Polo-like kinases (Plks) play an important role in cell cycle checkpoint controls and are over-expressed in acute myeloid leukaemia (AML). BI 2536, a novel Plk inhibitor, induces mitotic arrest and apoptosis. In this phase I/II trial of BI 2536 in 68 elderly patients with relapsed/refractory AML, three schedules were investigated (day 1, days 1-3, and days 1 + 8). Maximum tolerated dose was 350 and 200 mg in the day 1 and days 1 + 8 schedules, respectively. The day 1-3 schedule appeared equivalent to the day 1 schedule and was discontinued early. BI 2536 exhibited multi-compartmental pharmacokinetic behaviour. The majority of patients showed an increase of bone marrow cells in G2/M with a characteristic pattern of mitotic catastrophe. The overall response rate in the day 1 and day 1 + 8 schedules was 9% (5/54) with 2 complete and 3 partial responses. The majority of drug-related adverse events grade ≥3 were haematological. Taken together, Plk inhibition induced cell cycle arrest in AML blasts in vivo and BI 2536 monotherapy showed modest clinical activity in this poor prognosis patient group.

Modeling colon adenocarcinomas in vitro a 3D co-culture system induces cancer-relevant pathways upon tumor cell and stromal fibroblast interaction.

Activated tumor stroma participates in tumor cell growth, invasion, and metastasis. Normal fibroblasts and cancer-associated fibroblasts (CAFs) have been shown to display distinct gene expression signatures. This molecular heterogeneity may influence the way tumor cells migrate, proliferate, and survive during tumor progression. To test this hypothesis and to better understand the molecular mechanisms that control these interactions, we established a three-dimensional (3D) human cell culture system that recapitulates the tumor heterogeneity observed in vivo. Human colon tumor cells were grown as multicellular spheroids and subsequently co-cultured with normal fibroblasts or CAFs in collagen I gels. This in vitro model system closely mirrors the architecture of human epithelial cancers and allows the characterization of the tumor cell-stroma interactions phenotypically and at the molecular level. Using GeneChip analysis, antibody arrays, and enzyme-linked immunosorbent assays, we demonstrate that the interaction of colon cancer cells with stromal fibroblasts induced different highly relevant cancer expression profiles. Genes involved in invasion, extracellular matrix remodeling, inflammation, and angiogenesis were differentially regulated in our 3D carcinoma model. The modular setup, reproducibility, and robustness of the model make it a powerful tool to identify target molecules involved in signaling pathways that mediate paracrine interactions in the tumor microenvironment and to validate the influence of these molecular targets during tumor growth and invasion in the supporting stroma.

BI 2536, a potent and selective inhibitor of polo-like kinase 1, inhibits tumor growth in vivo.

Fine-mapping of the cell-division cycle, notably the identification of mitotic kinase signaling pathways, provides novel opportunities for cancer-drug discovery. As a key regulator of multiple steps during mitotic progression across eukaryotic species, the serine/threonine-specific Polo-like kinase 1 (Plk1) is highly expressed in malignant cells and serves as a negative prognostic marker in specific human cancer types . Here, we report the discovery of a potent small-molecule inhibitor of mammalian Plk1, BI 2536, which inhibits Plk1 enzyme activity at low nanomolar concentrations. The compound potently causes a mitotic arrest and induces apoptosis in human cancer cell lines of diverse tissue origin and oncogenome signature. BI 2536 inhibits growth of human tumor xenografts in nude mice and induces regression of large tumors with well-tolerated intravenous dose regimens. In treated tumors, cells arrest in prometaphase, accumulate phosphohistone H3, and contain aberrant mitotic spindles. This mitotic arrest is followed by a surge in apoptosis, detectable by immunohistochemistry and noninvasive optical and magnetic resonance imaging. For addressing the therapeutic potential of Plk1 inhibition, BI 2536 has progressed into clinical studies in patients with locally advanced or metastatic cancers.

BI 6727, a Polo-like kinase inhibitor with improved pharmacokinetic profile and broad antitumor activity.

PURPOSE: Antimitotic chemotherapy remains a cornerstone of multimodality treatment for locally advanced and metastatic cancers. To identify novel mitosis-specific agents with higher selectivity than approved tubulin-binding agents (taxanes, Vinca alkaloids), we have generated inhibitors of Polo-like kinase 1, a target that functions predominantly in mitosis. EXPERIMENTAL DESIGN: The first compound in this series, suitable for i.v. administration, has entered clinical development. To fully explore the potential of Polo-like kinase 1 inhibition in oncology, we have profiled additional compounds and now describe a novel clinical candidate. RESULTS: BI 6727 is a highly potent (enzyme IC(50) = 0.87 nmol/L, EC(50) = 11-37 nmol/L on a panel of cancer cell lines) and selective dihydropteridinone with distinct properties. First, BI 6727 has a pharmacokinetic profile favoring sustained exposure of tumor tissues with a high volume of distribution and a long terminal half-life in mice (V(ss) = 7.6 L/kg, t(1/2) = 46 h) and rats (V(ss) = 22 L/kg, t(1/2) = 54 h). Second, BI 6727 has physicochemical and pharmacokinetic properties that allow in vivo testing of i.v. as well as oral formulations, adding flexibility to dosing schedules. Finally, BI 6727 shows marked antitumor activity in multiple cancer models, including a model of taxane-resistant colorectal cancer. With oral and i.v. routes of administration, the total weekly dose of BI 6727 is most relevant for efficacy, supporting the use of a variety of well-tolerated dosing schedules. CONCLUSION: These findings warrant further investigation of BI 6727 as a tailored antimitotic agent; clinical studies have been initiated.

Effective immunoconjugate therapy in cancer models targeting a serine protease of tumor fibroblasts.

PURPOSE: Invasion and metastasis of malignant epithelial cells into normal tissues is accompanied by adaptive changes in the mesenchyme-derived supporting stroma of the target organs. Altered gene expression in these nontransformed stromal cells provides potential targets for therapy. The present study was undertaken to determine the antitumor effects of an antibody-conjugate against fibroblast activation protein-alpha, a cell surface protease of activated tumor fibroblasts. EXPERIMENTAL DESIGN: A novel antibody-maytansinoid conjugate, monoclonal antibody (mAb) FAP5-DM1, was developed to target a shared epitope of human, mouse, and cynomolgus monkey fibroblast activation protein-alpha, enabling preclinical efficacy and tolerability assessments. We have used stroma-rich models in immunodeficient mice, which recapitulate the histotypic arrangement found in human epithelial cancers. RESULTS: Treatment with mAb FAP5-DM1 induced long-lasting inhibition of tumor growth and complete regressions in xenograft models of lung, pancreas, and head and neck cancers with no signs of intolerability. Analysis of chemically distinct conjugates, resistance models, and biomarkers implicates a unique mode of action, with mitotic arrest and apoptosis of malignant epithelial cells coupled to disruption of fibroblastic and vascular structures. CONCLUSIONS: We show that mAb FAP5-DM1 combines excellent efficacy and tolerability and provides a first assessment of the mode of action of a novel drug candidate for tumor stroma targeting, thus encouraging further development toward clinical testing of this treatment paradigm.

hGPR87 contributes to viability of human tumor cells.

Emerging in vitro and in vivo data underline the crucial role of G-protein-coupled receptors (GPCRs) in tumorigenesis. Here, we report the contribution of hGPR87, a predicted member of the P2Y subfamily of GPCRs, to proliferation and survival of human tumor cell lines. hGPR87 mRNA transcript was found to be preferentially overexpressed in squamous cell carcinomas (SCCs) of different locations and in their lymph node metastases. Up-regulation of both, transcript and protein, was detected in samples of SCC of the lung, cervix, skin and head and neck (pharynx, larynx and epiglottis). In addition to the expression of hGPR87 in tumors which originate from stratified epithelia, we identified other hGPR87-positive tumor types including subsets of large cell and adenocarcinomas of the lung and transitional cell carcinomas of the urinary bladder. Loss of function studies using siRNA in human cancer cell lines lead to antiproliferative effects and induction of apoptosis. Like other known P2Y receptors, hGPR87 was found to be mainly located on the cell surface. The overexpression of hGPR87 preferentially in SCCs together with our functional data suggests a common molecular mechanism for SCC tumorigenesis and may provide a novel intervention site for mechanism-based antitumor therapies.

Efficacy of the highly selective focal adhesion kinase inhibitor BI 853520 in adenocarcinoma xenograft models is linked to a mesenchymal tumor phenotype.

Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, has attracted interest as a target for pharmacological intervention in malignant diseases. Here, we describe BI 853520, a novel ATP-competitive inhibitor distinguished by high potency and selectivity. In vitro, the compound inhibits FAK autophosphorylation in PC-3 prostate carcinoma cells with an IC50 of 1 nmol/L and blocks anchorage-independent proliferation of PC-3 cells with an EC50 of 3 nmol/L, whereas cells grown in conventional surface culture are 1000-fold less sensitive. In mice, the compound shows long half-life, high volume of distribution and high oral bioavailability; oral dosing of immunodeficient mice bearing subcutaneous PC-3 prostate adenocarcinoma xenografts resulted in rapid, long-lasting repression of FAK autophosphorylation in tumor tissue. Daily oral administration of BI 853520 to nude mice at doses of 50 mg/kg was well tolerated for prolonged periods of time. In a diverse panel of 16 subcutaneous adenocarcinoma xenograft models in nude mice, drug treatment resulted in a broad spectrum of outcomes, ranging from group median tumor growth inhibition values >100% and tumor regression in subsets of animals to complete lack of sensitivity. Biomarker analysis indicated that high sensitivity is linked to a mesenchymal tumor phenotype, initially defined by loss of E-cadherin expression and subsequently substantiated by gene set enrichment analysis. Further, we obtained microRNA expression profiles for 13 models and observed that hsa-miR-200c-3p expression is strongly correlated with efficacy (R2 = 0.889). BI 853520 is undergoing evaluation in early clinical trials.

Molecular characterization of the desmoplastic tumor stroma in medullary thyroid carcinoma.

Medullary thyroid carcinomas are aggressive neoplasias that metastasize very early to loco-regional lymph nodes, and tumors with a desmoplastic stromal reaction have a higher incidence of lymph node metastasis. In order to characterize the desmoplastic response in thyroid cancers, we evaluated the expression pattern of three molecular markers of activated fibroblasts/myofibroblasts, namely, fibroblast activation protein alpha (FAPalpha), tenascin-C (Tn-C), and alpha-smooth muscle actin (alpha-SMA), as well as the endothelial markers endoglyx-1, CD34 and CD31 in a series of 28 metastatic and non-metastatic medullary thyroid cancers. Immunohistochemical studies demonstrated that the three fibroblast activation markers (FAPalpha, Tn-C, alpha-SMA) are consistently expressed in the peritumoral and intratumoral stromal compartment of medullary thyroid carcinomas and expression of FAPalpha and Tn-C correlated with the degree of desmoplasia determined histologically (p=0.001 for FAPalpha and p<0.001 for Tn-C). Moreover, the extent of desmoplasia as well as the expression of FAPalpha and Tn-C correlated with the presence of lymph node (LN) metastases (p=0.002, p=0.005 and p=0.002, respectively). No correlation was found between the microvessel density (neoangiogenesis) in the tumor stroma, assessed with the endoglyx-1, CD34 and CD31 markers, and the degree of desmoplasia or incidence of LN metastases. Using a bioinformatics-based search of the BioExpresstrade mark database we found in a series of 48 thyroid cancers a significant correlation between FAPalpha RNA expression and incidence of LN metastases also in papillary cancers. These findings suggest that the link between specific molecular markers of tumor stromal reaction and locoregional metastasis extends from medullary to other thyroid cancer types.

The IGF1R/INSR Inhibitor BI 885578 Selectively Inhibits Growth of IGF2-Overexpressing Colorectal Cancer Tumors and Potentiates the Efficacy of Anti-VEGF Therapy.

Clinical studies of pharmacologic agents targeting the insulin-like growth factor (IGF) pathway in unselected cancer patients have so far demonstrated modest efficacy outcomes, with objective responses being rare. As such, the identification of selection biomarkers for enrichment of potential responders represents a high priority for future trials of these agents. Several reports have described high IGF2 expression in a subset of colorectal cancers, with focal IGF2 amplification being responsible for some of these cases. We defined a novel cut-off value for IGF2 overexpression based on differential expression between colorectal tumors and normal tissue samples. Analysis of two independent colorectal cancer datasets revealed IGF2 to be overexpressed at a frequency of 13% to 22%. An in vitro screen of 34 colorectal cancer cell lines revealed IGF2 expression to significantly correlate with sensitivity to the IGF1R/INSR inhibitor BI 885578. Furthermore, autocrine IGF2 constitutively activated IGF1R and Akt phosphorylation, which was inhibited by BI 885578 treatment. BI 885578 significantly delayed the growth of IGF2-high colorectal cancer xenograft tumors in mice, while combination with a VEGF-A antibody increased efficacy and induced tumor regression. Besides colorectal cancer, IGF2 overexpression was detected in more than 10% of bladder carcinoma, hepatocellular carcinoma and non-small cell lung cancer patient samples. Meanwhile, IGF2-high non-colorectal cancer cells lines displayed constitutive IGF1R phosphorylation and were sensitive to BI 885578. Our findings suggest that IGF2 may represent an attractive patient selection biomarker for IGF pathway inhibitors and that combination with VEGF-targeting agents may further improve clinical outcomes. Mol Cancer Ther; 16(10); 2223-33. ©2017 AACR.

Molecular dissection of colorectal cancer in pre-clinical models identifies biomarkers predicting sensitivity to EGFR inhibitors.

Colorectal carcinoma represents a heterogeneous entity, with only a fraction of the tumours responding to available therapies, requiring a better molecular understanding of the disease in precision oncology. To address this challenge, the OncoTrack consortium recruited 106 CRC patients (stages I-IV) and developed a pre-clinical platform generating a compendium of drug sensitivity data totalling >4,000 assays testing 16 clinical drugs on patient-derived in vivo and in vitro models. This large biobank of 106 tumours, 35 organoids and 59 xenografts, with extensive omics data comparing donor tumours and derived models provides a resource for advancing our understanding of CRC. Models recapitulate many of the genetic and transcriptomic features of the donors, but defined less complex molecular sub-groups because of the loss of human stroma. Linking molecular profiles with drug sensitivity patterns identifies novel biomarkers, including a signature outperforming RAS/RAF mutations in predicting sensitivity to the EGFR inhibitor cetuximab.

Mouse endosialin, a C-type lectin-like cell surface receptor: expression during embryonic development and induction in experimental cancer neoangiogenesis.

Endosialin is a C-type lectin-like cell surface receptor of unknown function, with a distinctive pattern of endothelial expression in newly formed blood vessels in human cancers. The murine orthologue of endosialin has been identified, opening up the analysis of developmental regulation in the embryo and in aberrant tissue remodeling, notably cancer angiogenesis. To advance these studies we have generated an antibody to the extracellular domain of mouse endosialin and mapped protein expression from embryonic day E10.0 to the adult stage, complemented by mRNA quantification and co-typing for standard endothelial markers. Four main findings emerged. First, endosialin protein is restricted to vascular endothelium and fibroblast-like cells in developing organs, and largely disappears in the adult. Second, endothelial expression varies markedly between organs regarding spatial and temporal patterns. For instance, in the E10.0 embryo, endosialin is prominent in the endothelium of the dorsal aorta and, from E11.0 to E14.5, in vessels sprouting from the dorsal aorta, in perineural vascular plexuses, and in brain capillaries. Third, circumscribed mesenchymal expression in fibroblast-like cells was evident throughout development, most pronounced adjacent to certain budding epithelia, as exemplified by the lung and kidney glomeruli, but unrelated to the endothelial expression. The endosialin protein persists in the stromal fibroblasts of the adult uterus. Finally, in subcutaneous cancer xenograft models endosialin re-appears in the host-derived tumor stroma, both in neo-angiogenic vascular endothelium and in activated stromal fibroblasts. In future studies, the search for intrinsic or extrinsic signals contributing to endosialin induction in cancer stroma will be of interest.

Laser capture microdissection of epithelial cancers guided by antibodies against fibroblast activation protein and endosialin.

Transcriptional profiling of cancer biopsies is used extensively to identify expression signatures for specific cancer types, diagnostic and prognostic subgroups, and novel molecular targets for therapy. To broaden these applications, several challenges remain. For example, the integrity of RNA extracted even from small tissue samples has to be insured and monitored. Moreover, total tumor RNA may hide the marked histologic heterogeneity of human cancers. A principle approach to this heterogeneity has been provided by laser capture microdissection performed on antibody-stained tissue sections (immuno-LCM; iLCM). In this study, we have established a procedure to assess the quality of RNA obtained from tissue sections, coupled with immunostaining using antibodies to different tumor stromal markers, and subsequent iLCM to selectively capture the cancer stroma compartments. The procedure was applied to 53 frozen specimens of human epithelial cancers. Sections were stained for histopathological evaluation, and RNA was isolated from adjacent serial sections. RNA quality was assessed by the Agilent-Bioanalyzer (Agilent, Palo Alto, CA) and by multiplex RT-PCR. Two thirds of the specimens were found to yield good to excellent RNA quality. For microdissection of the tumor stroma with reactive fibroblasts and tumor blood vessels, a rapid incubation protocol with antibodies against fibroblast activation protein (FAP) and against endosialin was developed to ensure RNA integrity for subsequent iLCM. Using these procedures, RNA from distinct tumor compartments can be isolated, analyzed, amplified, and used for transcription profiling.

A Novel RAF Kinase Inhibitor with DFG-Out-Binding Mode: High Efficacy in BRAF-Mutant Tumor Xenograft Models in the Absence of Normal Tissue Hyperproliferation.

BI 882370 is a highly potent and selective RAF inhibitor that binds to the DFG-out (inactive) conformation of the BRAF kinase. The compound inhibited proliferation of human BRAF-mutant melanoma cells with 100× higher potency (1-10 nmol/L) than vemurafenib, whereas wild-type cells were not affected at 1,000 nmol/L. BI 882370 administered orally was efficacious in multiple mouse models of BRAF-mutant melanomas and colorectal carcinomas, and at 25 mg/kg twice daily showed superior efficacy compared with vemurafenib, dabrafenib, or trametinib (dosed to provide exposures reached in patients). To model drug resistance, A375 melanoma-bearing mice were initially treated with vemurafenib; all tumors responded with regression, but the majority subsequently resumed growth. Trametinib did not show any efficacy in this progressing population. BI 882370 induced tumor regression; however, resistance developed within 3 weeks. BI 882370 in combination with trametinib resulted in more pronounced regressions, and resistance was not observed during 5 weeks of second-line therapy. Importantly, mice treated with BI 882370 did not show any body weight loss or clinical signs of intolerability, and no pathologic changes were observed in several major organs investigated, including skin. Furthermore, a pilot study in rats (up to 60 mg/kg daily for 2 weeks) indicated lack of toxicity in terms of clinical chemistry, hematology, pathology, and toxicogenomics. Our results indicate the feasibility of developing novel compounds that provide an improved therapeutic window compared with first-generation BRAF inhibitors, resulting in more pronounced and long-lasting pathway suppression and thus improved efficacy.

Volasertib Versus Chemotherapy in Platinum-Resistant or -Refractory Ovarian Cancer: A Randomized Phase II Groupe des Investigateurs Nationaux pour l'Etude des Cancers de l'Ovaire Study.

PURPOSE: Volasertib is a potent and selective cell-cycle kinase inhibitor that induces mitotic arrest and apoptosis by targeting Polo-like kinase. This phase II trial evaluated volasertib or single-agent chemotherapy in patients with platinum-resistant or -refractory ovarian cancer who experienced failure after treatment with two or three therapy lines. PATIENTS AND METHODS: Patients were randomly assigned to receive either volasertib 300 mg by intravenous infusion every 3 weeks or an investigator's choice of single-agent, nonplatinum, cytotoxic chemotherapy. The primary end point was 24-week disease control rate. Secondary end points included best overall response, progression-free survival (PFS), safety, quality of life, and exploratory biomarker analyses. RESULTS: Of the 109 patients receiving treatment, 54 received volasertib and 55 received chemotherapy; demographics were well balanced. The 24-week disease control rates for volasertib and chemotherapy were 30.6% (95% CI, 18.0% to 43.2%) and 43.1% (95% CI, 29.6% to 56.7%), respectively, with partial responses in seven (13.0%) and eight (14.5%) patients, respectively. Median PFS was 13.1 weeks and 20.6 weeks for volasertib and chemotherapy (hazard ratio, 1.01; 95% CI, 0.66 to 1.53). Six patients (11%) receiving volasertib achieved PFS fore more than 1 year, whereas no patient receiving chemotherapy achieved PFS greater than 1 year. No relationship between the expression of the biomarkers tested and their response was determined. Patients treated with volasertib experienced more grade 3 and 4 drug-related hematologic adverse events (AEs) and fewer nonhematologic AEs than did patients receiving chemotherapy. Discontinuation resulting from AEs occurred in seven (13.0%) and 15 (27.3%) patients in the volasertib and chemotherapy arms, respectively. Both arms showed similar effects on quality of life. CONCLUSION: Single-agent volasertib showed antitumor activity in patients with ovarian cancer. AEs in patients receiving volasertib were mainly hematologic and manageable.

Pharmacological Profile of BI 847325, an Orally Bioavailable, ATP-Competitive Inhibitor of MEK and Aurora Kinases.

Although the MAPK pathway is frequently deregulated in cancer, inhibitors targeting RAF or MEK have so far shown clinical activity only in BRAF- and NRAS-mutant melanoma. Improvements in efficacy may be possible by combining inhibition of mitogenic signal transduction with inhibition of cell-cycle progression. We have studied the preclinical pharmacology of BI 847325, an ATP-competitive dual inhibitor of MEK and Aurora kinases. Potent inhibition of MEK1/2 and Aurora A/B kinases by BI 847325 was demonstrated in enzymatic and cellular assays. Equipotent effects were observed in BRAF-mutant cells, whereas in KRAS-mutant cells, MEK inhibition required higher concentrations than Aurora kinase inhibition. Daily oral administration of BI 847325 at 10 mg/kg showed efficacy in both BRAF- and KRAS-mutant xenograft models. Biomarker analysis suggested that this effect was primarily due to inhibition of MEK in BRAF-mutant models but of Aurora kinase in KRAS-mutant models. Inhibition of both MEK and Aurora kinase in KRAS-mutant tumors was observed when BI 847325 was administered once weekly at 70 mg/kg. Our studies indicate that BI 847325 is effective in in vitro and in vivo models of cancers with BRAF and KRAS mutation. These preclinical data are discussed in the light of the results of a recently completed clinical phase I trial assessing safety, tolerability, pharmacokinetics, and efficacy of BI 847325 in patients with cancer. Mol Cancer Ther; 15(10); 2388-98. ©2016 AACR.

FAPalpha, a surface peptidase expressed during wound healing, is a tumor suppressor.

Fibroblast activation protein-alpha (FAP) is a cell surface serine protease expressed at sites of tissue remodeling in embryonic development. FAP is not expressed by mature somatic tissues except activated melanocytes and fibroblasts in wound healing or tumor stroma. FAP expression is specifically silenced in proliferating melanocytic cells during malignant transformation. To study the role of FAP as a tumor suppressor, the gene for mouse fap was cloned and mutated at the catalytic domain (FAP serine mutant, FSM). We found that expression of FAP or FSM at physiologic levels in mouse melanoma cells abrogated tumorigenicity. Remarkably, the mutant form FSM lacking specific serine protease activity was a more potent tumor suppressor. Tumor rejection was not due to adaptive immune responses because RAG1-/- mice challenged with melanoma cells expressing either FAP or FSM were not tumorigenic. In in vitro assays, FAP or FSM expression restored contact inhibition, led to cell cycle arrest at G0/G1 phase, and increased susceptibility to stress-induced apoptosis. Cell death in FAP+ or FSM+ melanoma cells was readily triggered by depletion of survival factors from the media, leading to subsequent activation of caspases via the intrinsic pathway. These results show that expression of FAP is a tumor suppressor that abrogates tumorigenicity through regulation of cell growth and survival.