Abstract 3326: Uncovering the molecular mechanisms which predict sensitivity to a novel src kinase inhibitor NXP900 to inform personalized healthcare strategies

We have previously described the discovery of a highly potent, selective and orally bioavailable Src kinase inhibitor NXP900 with a unique binding mode relative to other Src inhibitors under clinical development or approved (Temps et al 2021). This unique binding mode locks SRC in its native inactive conformation, thereby inhibiting both enzymatic and scaffolding functions. Also, in contrast to other Src inhibitors in the clinic, NXP900 exhibits a unique target selectivity profile with 1000 fold selectivity for Src over Abl kinase. The aim of this current study was to perform broad cancer cell line panel screening to inform disease positioning and identify predictive biomarkers of sensitivity for this novel class of Src kinase inhibitor. We describe the results of extensive cancer cell line panel profiling across a suite of 2-dimensional(D) and 3-D in vitro cell viability and high content phenotypic profiling assays that has revealed clear patterns of cell line sensitivity and insensitivity. Among the most sensitive cell line subtypes are, squamous cell carcinoma, Arid1A mutant ovarian clear cell carcinoma and subtypes of breast luminal A and triple negative breast cancer cell lines. HER2+ breast cancer lines appear insensitive to NXP900 indicating HER2 as a potential driver of resistance to NXP900. Further in-depth bioinformatic analysis of genetic and transcriptomic profiles of sensitive cell lines has identified putative biomarkers to support patient selection and personalized healthcare strategies. These studies demonstrate the identification of cancer cell lines which exhibit high sensitivity to NXP900 and which can be grouped into discrete molecular subtypes based on gene mutation status, transcriptomics and histotype. Our result provide an indication of patient subgroups which may exhibit optimal therapeutic response to NXP900 and provide data to guide further preclinical, biomarker and clinical development. Temps C et al., Cancer Res. 2021 Nov 1;81(21):5438-5450. doi: 10.1158/0008-5472.CAN-21-0613.

Citation Format: Neil Carragher, Rebecca Hughes, Valerie Brunton, Asier Unciti-broceta, Iñigo Lanzagorta-Calvillo, Carolin Temps, Enrique Poradosu. Uncovering the molecular mechanisms which predict sensitivity to a novel src kinase inhibitor NXP900 to inform personalized healthcare strategies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3326.

MISpheroID: a knowledgebase and transparency tool for minimum information in spheroid identity

Spheroids are three-dimensional cellular models with widespread basic and translational application across academia and industry. However, methodological transparency and guidelines for spheroid research have not yet been established. The MISpheroID Consortium developed a crowdsourcing knowledgebase that assembles the experimental parameters of 3,058 published spheroid-related experiments. Interrogation of this knowledgebase identified heterogeneity in the methodological setup of spheroids. Empirical evaluation and interlaboratory validation of selected variations in spheroid methodology revealed diverse impacts on spheroid metrics. To facilitate interpretation, stimulate transparency and increase awareness, the Consortium defines the MISpheroID string, a minimum set of experimental parameters required to report spheroid research. Thus, MISpheroID combines a valuable resource and a tool for three-dimensional cellular models to mine experimental parameters and to improve reproducibility.

Brain microenvironment-driven resistance to immune and targeted therapies in acral melanoma

BACKGROUND

Combination treatments targeting the MEK-ERK pathway and checkpoint inhibitors have improved overall survival in melanoma. Resistance to treatment especially in the brain remains challenging, and rare disease subtypes such as acral melanoma are not typically included in trials. Here we present analyses from longitudinal sampling of a patient with metastatic acral melanoma that became resistant to successive immune and targeted therapies.

METHODS

We performed whole-exome sequencing and RNA sequencing on an acral melanoma that progressed on successive immune (nivolumab) and targeted (dabrafenib) therapy in the brain to identify resistance mechanisms. In addition, we performed growth inhibition assays, reverse phase protein arrays and immunoblotting on patient-derived cell lines using dabrafenib in the presence or absence of cerebrospinal fluid (CSF) in vitro. Patient-derived xenografts were also developed to analyse response to dabrafenib.

RESULTS

Immune escape following checkpoint blockade was not due to loss of tumour cell recognition by the immune system or low neoantigen burden, but was associated with distinct changes in the microenvironment. Similarly, resistance to targeted therapy was not associated with acquired mutations but upregulation of the AKT/phospho-inositide 3-kinase pathway in the presence of CSF.

CONCLUSION

Heterogeneous tumour interactions within the brain microenvironment enable progression on immune and targeted therapies and should be targeted in salvage treatments.

Highly Conserved Homotrimer Cavity Formed by the SARS-CoV-2 Spike Glycoprotein: A Novel Binding Site

An important stage in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) life cycle is the binding of the spike (S) protein to the angiotensin converting enzyme-2 (ACE2) host cell receptor. Therefore, to explore conserved features in spike protein dynamics and to identify potentially novel regions for drugging, we measured spike protein variability derived from 791 viral genomes and studied its properties by molecular dynamics (MD) simulation. The findings indicated that S2 subunit (heptad-repeat 1 (HR1), central helix (CH), and connector domain (CD) domains) showed low variability, low fluctuations in MD, and displayed a trimer cavity. By contrast, the receptor binding domain (RBD) domain, which is typically targeted in drug discovery programs, exhibits more sequence variability and flexibility. Interpretations from MD simulations suggest that the monomer form of spike protein is in constant motion showing transitions between an "up" and "down" state. In addition, the trimer cavity may function as a "bouncing spring" that may facilitate the homotrimer spike protein interactions with the ACE2 receptor. The feasibility of the trimer cavity as a potential drug target was examined by structure based virtual screening. Several hits were identified that have already been validated or suggested to inhibit the SARS-CoV-2 virus in published cell models. In particular, the data suggest an action mechanism for molecules including Chitosan and macrolides such as the mTOR (mammalian target of Rapamycin) pathway inhibitor Rapamycin. These findings identify a novel small molecule binding-site formed by the spike protein oligomer, that might assist in future drug discovery programs aimed at targeting the coronavirus (CoV) family of viruses.

Novel roles of PRK1 and PRK2 in cilia and cancer biology

PRK1 and PRK2 are two closely related AGC-family serine/threonine protein kinases. Here we demonstrate novel roles for them at cilia and in cancer biology. In both instances serum withdrawal leads to increased activating PRK1 and PRK2 phosphorylation (pPRK1/pPRK2) and their depletion results in reduced spheroid growth. pPRK1/pPRK2 localise to the transition zone of cilia and their co-depletion results in reduced cilia size, impaired planer polarity and impaired cilia associated signalling. High PRK2 (but not PRK1) expression correlates with poor outcome in patients with basal-like/Triple Negative (TN) Breast Cancer (BC) where there is also higher expression relative to other BC tumour subtypes. In agreement, depletion of PRK1 and PRK2 in mouse TNBC cells, or CRISPR/Cas9 mediated deletion of PRK2 alone, significantly reduces cell proliferation and spheroid growth. Finally proteomic analysis to identify PRK2 binding partners in mouse TNBC cells revealed proteins that are important for both cilia and BC biology. Taken together these data demonstrate novel roles for PRK1 and PRK2 at cilia and in BC biology and in the case of PRK2 in particular, identifies it as a novel TNBC therapeutic target.

The oncogene Gankyrin is expressed in testicular cancer and contributes to cisplatin sensitivity in embryonal carcinoma cells

Background

Testicular germ cell cancer (TGCC) develops from pre-malignant germ neoplasia in situ (GCNIS) cells. GCNIS originates from fetal gonocytes (POU5F1⁺/MAGE-A4⁻), which fail to differentiate to pre-spermatogonia (POU5F1⁻/MAGE-A4⁺) and undergo malignant transformation. Gankyrin is an oncogene which has been shown to prevent POU5F1 degradation and specifically interact with MAGE-A4 in hepatocellular carcinoma (HCC) cells. We aimed to investigate the role of Gankyrin in progression from gonocyte to pre-invasive GCNIS and subsequent invasive TGCC.

Methods

We determined Gankyrin expression in human fetal testicular tissue (gestational weeks 9–20; n = 38), human adult testicular tissue with active spermatogenesis (n = 9), human testicular tissue with germ cell maturation delay (n = 4), testicular tissue from patients with pre-invasive GCNIS (n = 6), and invasive TGCC including seminoma (n = 6) and teratoma (n = 7). Functional analysis was performed in-vitro by siRNA knock-down of Gankyrin in the NTera2 cells (derived from embryonal carcinoma).

Results

Germ cell expression of Gankyrin was restricted to a sub-population of prespermatogonia in human fetal testes. Nuclear Gankyrin was also expressed in GCNIS cells of childhood and adult pre-invasive TGCC patients, and in GCNIS from seminoma and non-seminoma patients. Cytoplasmic expression was observed in seminoma tumour cells and NTera2 cells. Gankyrin knock-down in NTera2 cells resulted in an increase in apoptosis mediated via the TP53 pathway, whilst POU5F1 expression was unaffected. Furthermore, Gankyrin knock-down in NTera2 cells increased cisplatin sensitivity with an increase in cell death (13%, p < 0.05) following Gankyrin knock-down, when compared to cisplatin treatment alone, likely via BAX and FAS. Our results demonstrate that Gankyrin expression changes in germ cells during normal transition from gonocyte to prespermatogonia. In addition, changes in Gankyrin localisation are associated with progression of pre-invasive GCNIS to invasive TGCC. Furthermore, we found that Gankyrin is involved in the regulation of NTera2 cell survival and that a reduction in Gankyrin expression can modulate cisplatin sensitivity.

Conclusions

These results suggest that manipulation of Gankyrin expression may reduce the cisplatin dose required for the treatment of TGCC, with benefits in reducing dose-dependent side effects of chemotherapy. Further studies are required in order to assess the effects of modulating Gankyrin on GCNIS/TGCC using in vivo models.

Mammary Tumor Cells with High Metastatic Potential Are Hypersensitive to Macrophage-Derived HGF

Metastasis-associated macrophages (MAM) promote persistent growth of breast cancer cells at the metastatic site and are, thus, an attractive therapeutic target to treat breast cancer metastasis, a leading cause of cancer-related death in women. However, the precise mechanisms behind MAM-mediated metastatic tumor outgrowth have not been fully elucidated. Using mouse models of metastatic breast cancer, we showed that MAMs uniquely expressed hepatocyte growth factor (HGF) in metastatic tumors. We also demonstrated that a selected population of cancer cells with high metastatic potential (cancer cells that can establish metastatic tumors in mice with higher number and incidence than parental cells) had higher expression of HGF receptor, MNNG HOS transforming gene (MET), and were more responsive to HGF released from macrophages compared with the parental cells. Blockade of MET signaling in cancer cells suppressed metastatic tumor expansion, in part, through activation of natural killer cells. Results from this study suggest an approach to prevent life-threatening metastatic tumor formation using blockade of MAM-induced MET signal activation in metastatic cancer cells.

A computationally designed binding mode flip leads to a novel class of potent tri-vector cyclophilin inhibitors

Cyclophilins (Cyps) are a major family of drug targets that are challenging to prosecute with small molecules because the shallow nature and high degree of conservation of the active site across human isoforms offers limited opportunities for potent and selective inhibition. Herein a computational approach based on molecular dynamics simulations and free energy calculations was combined with biophysical assays and X-ray crystallography to explore a flip in the binding mode of a reported urea-based Cyp inhibitor. This approach enabled access to a distal pocket that is poorly conserved among key Cyp isoforms, and led to the discovery of a new family of sub-micromolar cell-active inhibitors that offer unprecedented opportunities for the development of next-generation drug therapies based on Cyp inhibition. The computational approach is applicable to a broad range of organic functional groups and could prove widely enabling in molecular design.

Assessing distress in the community: psychometric properties and crosswalk comparison of eight measures of psychological distress

BACKGROUND

Many measures are available for measuring psychological distress in the community. Limited research has compared these scales to identify the best performing tools. A common metric for distress measures would enable researchers and clinicians to equate scores across different measures. The current study evaluated eight psychological distress scales and developed crosswalks (tables/figures presenting multiple scales on a common metric) to enable scores on these scales to be equated.

METHODS

An Australian online adult sample (N = 3620, 80% female) was administered eight psychological distress measures: Patient Health Questionnaire-4, Kessler-10/Kessler-6, Distress Questionnaire-5 (DQ5), Mental Health Inventory-5, Hopkins Symptom Checklist-25 (HSCL-25), Self-Report Questionnaire-20 (SRQ-20) and Distress Thermometer. The performance of each measure in identifying DSM-5 criteria for a range of mental disorders was tested. Scale fit to a unidimensional latent construct was assessed using Confirmatory Factor Analysis (CFA). Finally, crosswalks were developed using Item Response Theory.

RESULTS

The DQ5 had optimal performance in identifying individuals meeting DSM-5 criteria, with adequate fit to a unidimensional construct. The HSCL-25 and SRQ-20 also had adequate fit but poorer specificity and/or sensitivity than the DQ5 in identifying caseness. The unidimensional CFA of the combined item bank for the eight scales showed acceptable fit, enabling the creation of crosswalk tables.

CONCLUSIONS

The DQ5 had optimal performance in identifying risk of mental health problems. The crosswalk tables developed in this study will enable rapid conversion between distress measures, providing more efficient means of data aggregation and a resource to facilitate interpretation of scores from multiple distress scales.

Monocytes Differentiate to Immune Suppressive Precursors of Metastasis-Associated Macrophages in Mouse Models of Metastatic Breast Cancer

Metastasis-associated macrophages (MAMs) play pivotal roles in breast cancer metastasis by promoting extravasation and survival of metastasizing cancer cells. In a metastatic breast cancer mouse model, we previously reported that circulating classical monocytes (C-MOs) preferentially migrated into the tumor-challenged lung where they differentiated into MAMs. However, the fate and characteristics of C-MOs in the metastatic site has not been defined. In this study, we identified that adoptively transferred C-MOs (F4/80^lowCD11b⁺Ly6C⁺) differentiated into a distinct myeloid cell population that is characterized as F4/80^highCD11b^highLy6C^high and gives rise to MAMs (F4/80^lowCD11b^highLy6C^low) within 18 h after migration into the metastatic lung. In mouse models of breast cancer, the CD11b^highLy6C^high MAM precursor cells (MAMPCs) were commonly found in the metastatic lung, and their accumulation was increased during metastatic tumor growth. The morphology and gene expression profile of MAMPCs were distinct from C-MOs and had greater similarity to MAMs. For example MAMPCs expressed mature macrophage markers such as CD14, CD36, CD64, and CD206 at comparable levels with MAMs, suggesting that MAMPCs have committed to a macrophage lineage in the tumor microenvironment. MAMPCs also expressed higher levels of Arg1, Hmox1, and Stab1 than C-MOs to a comparable level to MAMs. Expression of these MAM-associated genes in MAMPCs was reduced by genetic deletion of colony-stimulating factor 1 receptor (CSF1R). On the other hand, transient CSF1R blockade did not reduce the number of MAMPCs in the metastatic site, suggesting that CSF1 signaling is active in MAMPCs but is not required for their accumulation. Functionally MAMPCs suppressed the cytotoxicity of activated CD8⁺ T cells in vitro in part through superoxide production. Overall, our results indicate that immediately following migration into the metastatic tumors C-MOs differentiate into immunosuppressive cells that have characteristics of monocytic myeloid-derived suppressor cell phenotype and might be targeted to enhance efficacy of immunotherapy for metastatic breast cancer.

Combined universal and selective prevention for adolescent alcohol use: a cluster randomized controlled trial

BACKGROUND

No existing models of alcohol prevention concurrently adopt universal and selective approaches. This study aims to evaluate the first combined universal and selective approach to alcohol prevention.

METHOD

A total of 26 Australian schools with 2190 students (mean age: 13.3 years) were randomized to receive: universal prevention (Climate Schools); selective prevention (Preventure); combined prevention (Climate Schools and Preventure; CAP); or health education as usual (control). Primary outcomes were alcohol use, binge drinking and alcohol-related harms at 6, 12 and 24 months.

RESULTS

Climate, Preventure and CAP students demonstrated significantly lower growth in their likelihood to drink and binge drink, relative to controls over 24 months. Preventure students displayed significantly lower growth in their likelihood to experience alcohol harms, relative to controls. While adolescents in both the CAP and Climate groups demonstrated slower growth in drinking compared with adolescents in the control group over the 2-year study period, CAP adolescents demonstrated faster growth in drinking compared with Climate adolescents.

CONCLUSIONS

Findings support universal, selective and combined approaches to alcohol prevention. Particularly novel are the findings of no advantage of the combined approach over universal or selective prevention alone.

Abstract 3796: Targeting cancer stem cells using ALDH-dependent 5-nitrofuran prodrugs

We hypothesise that cancer stem cells with high aldehyde dehydrogenase (ALDHhigh) activity present a new therapeutic target and will be selectively sensitive to 5-nitrofuran pro-drugs.

Cancers are heterogeneous and contain subpopulations of ALDHhigh cells with tumour initiating potential. ALDH enzymes metabolize toxic aldehydes, and are highly expressed in somatic and cancer stem cells (CSCs), although their function in stem cells is not fully understood. In a small molecule screen coupled with target ID, we recently discovered that clinically active 5-nitrofurans (5-NFNs) are substrates of ALDH2 (Zhou et al., 2012). 5-NFNs are a class of pro-drug widely used to treat bacterial and parasitic infections where their relative specificity is driven by nitroreductases, but little is known about the enzymes that bio-activate 5-NFNs in humans. Recent clinical cancer research has found that the 5-NFN nifurtimox has anti-cancer properties and it is currently in Phase 2 clinical trials for neuroblastoma and medulloblastoma (ClinicalTrials.gov Identifier: NCT00601003), however the mechanism underlying this anti-cancer activity is unknown.

In melanoma and other cancers, ALDH1A1 and ALDH1A3 are highly expressed in CSCs. We find that cancer cell lines are highly sensitive to 5-NFNs in cell viability assays, where we use a logarithmic drug dose range and assess cell viability by PrestoBlue™ (e.g. A375 melanoma cells EC50 = 86nM). To test if ALDH1 isoforms are substrates of 5-NFNs, we preformed in vitro activity assays by monitoring NADH production (λ = 340nm). We find that the clinically active 5-NFNs nifuroxazide and nifurtimox, in addition to our own newly synthesised 5-NFNs, are competitive substrates for human ALDH1A3 activity in vitro (p&lt;0.05). Notably, nifuroxazide was not a substrate for ALDH2, suggesting that nifuroxazide may show selectivity toward ALDH1. Consistent with our enzymatic activity assays, we find that 5-NFNs are competitive substrates for ALDH activity in melanoma cells by Aldefluor™ in vivo, with 5-NFNs displaying a prolonged competitive inhibition compared with the known inhibitor, DEAB. Importantly, no-nitro control compounds show no activity toward ALDH enzymes in vitro or in vivo. Computational docking studies reveal that 5-NFNs have the potential to fit within the interior of the ALDH enzymatic cavity and interact with the catalytic cysteine, thereby offering a potential mechanism for 5-NFN bio-activation. Kinetic living-cell imaging (IncuCyte ZOOM®) reveals that ALDH1A3 siRNA transfected A375 cells are protected from 5-NFN toxicity (p&gt;0.05) and apoptosis (DRAQ7™: p&lt;0.0001), demonstrating a functional role for ALDH1A3 in mediating 5-NFN activity in cancer cells.

Our work demonstrates a novel and biologically relevant 5-NFN-ALDH1 interaction in cancer cells. We propose 5-NFNs have the potential to target ALDHhigh CSCs within a tumour and advance the repurposing of clinical 5-NFN pro-drug antibiotics as anti-cancer therapeutics.

Citation Format: Richard Crispin, Nathalie M. Spockeli, Val Brunton, Neil Carragher, Charlie Gourley, Douglas R. Houston, Asier Unciti-Broceta, E. Elizabeth Patton. Targeting cancer stem cells using ALDH-dependent 5-nitrofuran prodrugs. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3796.

The structure of adolescent psychopathology: a symptom-level analysis

BACKGROUND

Most empirical studies into the covariance structure of psychopathology have been confined to adults. This work is not developmentally informed as the meaning, age-of-onset, persistence and expression of disorders differ across the lifespan. This study investigates the underlying structure of adolescent psychopathology and associations between the psychopathological dimensions and sex and personality risk profiles for substance misuse and mental health problems.

METHOD

This study analyzed data from 2175 adolescents aged 13.3 years. Five dimensional models were tested using confirmatory factor analysis and the external validity was examined using a multiple-indicators multiple-causes model.

RESULTS

A modified bifactor model, with three correlated specific factors (internalizing, externalizing, thought disorder) and one general psychopathology factor, provided the best fit to the data. Females reported higher mean levels of internalizing, and males reported higher mean levels of externalizing. No significant sex differences emerged in liability to thought disorder or general psychopathology. Liability to internalizing, externalizing, thought disorder and general psychopathology was characterized by a number of differences in personality profiles.

CONCLUSIONS

This study is the first to identify a bifactor model including a specific thought disorder factor. The findings highlight the utility of transdiagnostic treatment approaches and the importance of restructuring psychopathology in an empirically based manner.

Abstract C25: Targeting cancer stem cells using ALDH-dependent 5-nitrofuran pro-drugs

We hypothesise that cancer stem cells with high aldehyde dehydrogenase (ALDHhigh) activity present a new therapeutic target and will be selectively sensitive to 5-nitrofuran pro-drugs.

Cancers are heterogeneous and contain subpopulations of ALDHhigh cells with tumour initiating potential. ALDH enzymes metabolize toxic aldehydes, and are highly expressed in somatic and cancer stem cells (CSCs), although their function in stem cells is not fully understood. In a small molecule screen coupled with target ID, we recently discovered that clinically active 5-nitrofurans (5-NFNs) are substrates of ALDH2 (Zhou et al., 2012). 5-NFNs are a class of pro-drug widely used to treat bacterial and parasitic infections where their relative specificity is driven by nitroreductases, but little is known about the enzymes that bio-activate 5-NFNs in humans. Recent clinical cancer research has found that the 5-NFN nifurtimox has anti-cancer properties and it is currently in Phase 2 clinical trials for neuroblastoma and medulloblastoma (ClinicalTrials.gov Identifier: NCT00601003), however the mechanism underlying this anti-cancer activity is unknown.

In melanoma and other cancers, ALDH1A1 and ALDH1A3 are highly expressed in CSCs. We find that cancer cell lines are highly sensitive to 5-NFNs in cell viability assays, where we use a logarithmic drug dose range and assess cell viability by PrestoBlue™ (e.g. A375 melanoma cells EC50 = 86nM). To test if ALDH1 isoforms are substrates of 5-NFNs, we preformed in vitroactivity assays by monitoring NADH production (λ = 340nm). We find that the clinically active 5-NFNs nifuroxazide and nifurtimox, in addition to our own newly synthesised 5-NFNs, are competitive substrates for human ALDH1A3 activity in vitro (p&lt;0.05). Notably, nifuroxazide was not a substrate for ALDH2, suggesting that nifuroxazide may show selectivity toward ALDH1 isoforms. Consistent with our enzymatic activity assays, we find that 5-NFNs are competitive substrates for ALDH activity in melanoma cells by Aldefluor™ in vivo, with 5-NFNs displaying a prolonged competitive inhibition compared with the known inhibitor, DEAB. Importantly, no-nitro control compounds show no activity toward ALDH enzymes in vitro or in vivo. Computational docking studies reveal that 5-NFNs have the potential to fit within the interior of the ALDH enzymatic cavity and interact with the catalytic cysteine, thereby offering a potential mechanism for 5-NFN bio-activation. Kinetic living-cell imaging (IncuCyte ZOOM®) reveals that ALDH1A3 siRNA transfected A375 cells are protected from 5-NFN toxicity (p&gt;0.05) and apoptosis (DRAQ7™: p&lt;0.0001), demonstrating a functional role for ALDH1A3 in mediating 5-NFN activity in cancer cells.

Our work demonstrates a novel and biologically relevant 5-NFN-ALDH1 interaction in cancer cells. We propose 5-NFNs have the potential to target ALDHhigh CSCs within a tumour and advance the repurposing of clinical 5-NFN pro-drug antibiotics as anti-cancer therapeutics.

Citation Format: Richard Crispin, Nathalie Spockeli, Val Brunton, Neil Carragher, Charlie Gourley, Douglas Houston, Asier Unciti-Broceta, E. Elizabeth Patton. Targeting cancer stem cells using ALDH-dependent 5-nitrofuran pro-drugs. [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2015 Nov 5-9; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2015;14(12 Suppl 2):Abstract nr C25.

Paradox-breaking RAF inhibitors that also target SRC are effective in drug-resistant BRAF mutant melanoma

BRAF and MEK inhibitors are effective in BRAF mutant melanoma, but most patients eventually relapse with acquired resistance, and others present intrinsic resistance to these drugs. Resistance is often mediated by pathway reactivation through receptor tyrosine kinase (RTK)/SRC-family kinase (SFK) signaling or mutant NRAS, which drive paradoxical reactivation of the pathway. We describe pan-RAF inhibitors (CCT196969, CCT241161) that also inhibit SFKs. These compounds do not drive paradoxical pathway activation and inhibit MEK/ERK in BRAF and NRAS mutant melanoma. They inhibit melanoma cells and patient-derived xenografts that are resistant to BRAF and BRAF/MEK inhibitors. Thus, paradox-breaking pan-RAF inhibitors that also inhibit SFKs could provide first-line treatment for BRAF and NRAS mutant melanomas and second-line treatment for patients who develop resistance.

Abstract 3704: Novel panRAF inhibitors active in melanomas that are resistant to BRAF-selective, or BRAF-selective/MEK inhibitor combinations

The protein kinase BRAF is mutated ∼40% of human melanomas. BRAF is a component of the RAS/RAF/MEK/ERK pathway and BRAF or MEK inhibitors increase progression-free and overall survival in melanoma patients with BRAF mutations. However, most patients relapse with acquired resistance and ∼20% of patients present intrinsic resistance and do not respond to these drugs. We describe here two novel compounds that target mutant BRAF and wild-type CRAF. Our compounds inhibited the growth of melanoma cells that were resistant to BRAF-selective inhibitors. ERK pathway reactivation is responsible for resistance to BRAF targeted therapies in ∼60% of the patients and in ∼25% of patients resistance is driven by acquisition of mutations in NRAS. We show that our compounds inhibited the growth of melanoma cells that were resistant to BRAF-selective inhibitors due to pathway reactivation mediated by different mechanisms. We show that the drugs were active against patient derived xenografts (PDXs) from patients with acquired or intrinsic resistance to BRAF-selective inhibitors and in whose tumors resistance was associated with ERK pathway reactivation. Further, our compounds are active in a PDX from a patient whose tumor developed acquired resistance to a combination of a BRAF-selective plus a MEK inhibitor and associated with acquisition of an NRAS mutation. Thus, our panRAF inhibitors can inhibit melanomas with different mechanisms of acquired or intrinsic resistance to BRAF-selective and BRAF-selective/MEK inhibitor combinations, potentially providing first-line treatment for naïve patients and second-line treatments for a range of relapsed patients.

Citation Format: Maria R. Girotti, Filipa Lopes, Natasha Preece, Dan Niculescu-Duvaz, Alfonso Zambon, Lawrence Davies, Steven Whittaker, Grazia Saturno, Amaya Viros, Malin Pedersen, Bart MJM Suijkerbuijk, Delphine Menard, Robert Mcleary, Louise Johnson, Laura Fish, Sarah Ejiama, Berta Sanchez-Laorden, Neil Carragher, Kenneth Macleod, Garry Ashton, Anna Marusiak, Alberto Fusi, John Brognard, Margaret Frame, Paul Lorigan, Caroline J. Springer, Richard Marais. Novel panRAF inhibitors active in melanomas that are resistant to BRAF-selective, or BRAF-selective/MEK inhibitor combinations. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3704. doi:10.1158/1538-7445.AM2014-3704

Realizing the promise of reverse phase protein arrays for clinical, translational, and basic research: a workshop report: the RPPA (Reverse Phase Protein Array) society

Reverse phase protein array (RPPA) technology introduced a miniaturized "antigen-down" or "dot-blot" immunoassay suitable for quantifying the relative, semi-quantitative or quantitative (if a well-accepted reference standard exists) abundance of total protein levels and post-translational modifications across a variety of biological samples including cultured cells, tissues, and body fluids. The recent evolution of RPPA combined with more sophisticated sample handling, optical detection, quality control, and better quality affinity reagents provides exquisite sensitivity and high sample throughput at a reasonable cost per sample. This facilitates large-scale multiplex analysis of multiple post-translational markers across samples from in vitro, preclinical, or clinical samples. The technical power of RPPA is stimulating the application and widespread adoption of RPPA methods within academic, clinical, and industrial research laboratories. Advances in RPPA technology now offer scientists the opportunity to quantify protein analytes with high precision, sensitivity, throughput, and robustness. As a result, adopters of RPPA technology have recognized critical success factors for useful and maximum exploitation of RPPA technologies, including the following: preservation and optimization of pre-analytical sample quality, application of validated high-affinity and specific antibody (or other protein affinity) detection reagents, dedicated informatics solutions to ensure accurate and robust quantification of protein analytes, and quality-assured procedures and data analysis workflows compatible with application within regulated clinical environments. In 2011, 2012, and 2013, the first three Global RPPA workshops were held in the United States, Europe, and Japan, respectively. These workshops provided an opportunity for RPPA laboratories, vendors, and users to share and discuss results, the latest technology platforms, best practices, and future challenges and opportunities. The outcomes of the workshops included a number of key opportunities to advance the RPPA field and provide added benefit to existing and future participants in the RPPA research community. The purpose of this report is to share and disseminate, as a community, current knowledge and future directions of the RPPA technology.

Ret inhibition decreases growth and metastatic potential of estrogen receptor positive breast cancer cells

We show that elevated levels of Ret receptor are found in different sub-types of human breast cancers and that high Ret correlates with decreased metastasis-free survival. The role of Ret in ER+ breast cancer models was explored combining in vitro and in vivo approaches. Our analyses revealed that ligand-induced Ret activation: (i) stimulates migration of breast cancer cells; (ii) rescues cells from anti-proliferative effects of endocrine treatment and (iii) stimulates expression of cytokines in the presence of endocrine agents. Indeed, we uncovered a positive feed-forward loop between the inflammatory cytokine IL6 and Ret that links them at the expression and the functional level. In vivo inhibition of Ret in a metastatic breast cancer model inhibits tumour outgrowth and metastatic potential. Ret inhibition blocks the feed-forward loop by down-regulating Ret levels, as well as decreasing activity of Fak, an integrator of IL6-Ret signalling. Our results suggest that Ret kinase should be considered as a novel therapeutic target in subsets of breast cancer.

Psychometric evaluation of the DSM-IV criterion B mania symptoms in an Australian national sample

BACKGROUND

Although numerous studies have examined the latent structure of major depression, less attention has focused on mania. This paper presents the first investigation outside the USA to evaluate the psychometric properties of the DSM-IV criterion B mania symptoms using item response theory (IRT).

METHOD

Data were drawn from the Australian 2007 National Survey of Mental Health and Well-Being (NSMHWB, n = 8841). The psychometric performance of the mania symptoms was evaluated using a two-parameter logistic model. Because substance use disorders (SUDs) frequently co-occur with mania and can influence manic symptom expression, differential item functioning (DIF) between mania respondents with/without a SUD diagnosis was also assessed.

RESULTS

Factor analysis supported a unidimensional trait underlying mania. The grandiosity symptom displayed the highest discrimination whereas discrimination was lowest for decreased need for sleep. Relatively speaking, grandiosity tapped the severe end and increased goal-oriented activities tapped the mild end of the mania severity continuum. The symptoms generally performed equivalently between those with/without a SUD diagnosis, with one exception; the activities with painful consequences symptom was endorsed at lower levels of severity, and hence more frequently, by those with a SUD diagnosis versus those without a SUD diagnosis.

CONCLUSIONS

Accurate conceptualization of latent structure has crucial theoretical, statistical and clinical implications. The symptoms generally performed well in distinguishing between respondents with differing levels of liability, but others did not, suggesting modification is warranted to ensure optimal use in epidemiological samples. Given the dearth of psychometric evaluation studies of mania, further research replicating these results is necessary.

Preclinical anticancer activity of the potent, oral Src inhibitor AZD0530

AZD0530, an orally available Src inhibitor, demonstrated potent antimigratory and anti-invasive effects in vitro, and inhibited metastasis in a murine model of bladder cancer. Antiproliferative activity of AZD0530 in vitro varied between cell lines (IC(50) 0.2 ->10μM). AZD0530 inhibited tumor growth in 4/10 xenograft models tested and dynamically inhibited in vivo phosphorylation of Src substrates paxillin and FAK in both growth-inhibition-resistant and -sensitive xenografts. The activity of AZD0530 in NBT-II bladder cancer cells in vitro was consistent with inhibition of cell migration and stabilization of cell-cell adhesion. These data suggest a dominant anti-invasive pharmacology for AZD0530 that may limit tumor progression in a range of cancers. AZD0530 is currently in Phase II clinical trials.