Brk/PTK6 and Involucrin Expression May Predict Breast Cancer Cell Responses to Vitamin D3.

The process of human embryonic mammary development gives rise to the structures in which mammary cells share a developmental lineage with skin epithelial cells such as keratinocytes. As some breast carcinomas have previously been shown to express high levels of involucrin, a marker of keratinocyte differentiation, we hypothesised that some breast tumours may de-differentiate to a keratinocyte-derived 'evolutionary history'. To confirm our hypothesis, we investigated the frequency of involucrin expression along with that of Brk, a tyrosine kinase expressed in up to 86% of breast carcinomas whose normal expression patterns are restricted to differentiating epithelial cells, most notably those in the skin (keratinocytes) and the gastrointestinal tract.

HSF1 Pathway Inhibitor Clinical Candidate (CCT361814/NXP800) Developed from a Phenotypic Screen as a Potential Treatment for Refractory Ovarian Cancer and Other Malignancies.

CCT251236 , a potent chemical probe, was previously developed from a cell-based phenotypic high-throughput screen (HTS) to discover inhibitors of transcription mediated by HSF1, a transcription factor that supports malignancy. Owing to its activity against models of refractory human ovarian cancer, was progressed into lead optimization. The reduction of P-glycoprotein efflux became a focus of early compound optimization; central ring halogen substitution was demonstrated by matched molecular pair analysis to be an effective strategy to mitigate this liability.

HMGB1 mediates invasion and PD-L1 expression through RAGE-PI3K/AKT signaling pathway in MDA-MB-231 breast cancer cells.

Background: High-mobility group box 1 (HMGB1) is increased in breast cancer cells as the result of exposure to the secreted substances from cancer-associated fibroblasts and plays a crucial role in cancer progression and drug resistance. Its effect, however, on the expression of programmed death ligand 1 (PD-L1) in breast cancer cells has not been investigated. This study aimed to investigate the mechanism of HMGB1 through receptors for advanced glycation end products (RAGE) on cell migration/invasion and PD-L1 expression in breast cancer cells.

Breast Tumour Kinase (Brk/PTK6) Contributes to Breast Tumour Xenograft Growth and Modulates Chemotherapeutic Responses In Vitro.

Breast tumour kinase (Brk/PTK6) is overexpressed in up to 86% of breast cancers and is associated with poorer patient outcomes. It is considered a potential therapeutic target in breast cancer, even though the full spectrum of its kinase activity is not known. This study investigated the role of the kinase domain in promoting tumour growth and its potential in sensitising triple negative breast cancer cells to standard of care chemotherapy.

Orally bioavailable CDK9/2 inhibitor shows mechanism-based therapeutic potential in MYCN-driven neuroblastoma.

The undruggable nature of oncogenic Myc transcription factors poses a therapeutic challenge in neuroblastoma, a pediatric cancer in which MYCN amplification is strongly associated with unfavorable outcome. Here, we show that CYC065 (fadraciclib), a clinical inhibitor of CDK9 and CDK2, selectively targeted MYCN-amplified neuroblastoma via multiple mechanisms. CDK9 - a component of the transcription elongation complex P-TEFb - bound to the MYCN-amplicon superenhancer, and its inhibition resulted in selective loss of nascent MYCN transcription.

Metabolomic changes of the multi (-AGC-) kinase inhibitor AT13148 in cells, mice and patients are associated with NOS regulation.

Introduction: To generate biomarkers of target engagement or predictive response for multi-target drugs is challenging. One such compound is the multi-AGC kinase inhibitor AT13148. Metabolic signatures of selective signal transduction inhibitors identified in preclinical models have previously been confirmed in early clinical studies.

Quizartinib-resistant FLT3-ITD acute myeloid leukemia cells are sensitive to the FLT3-Aurora kinase inhibitor CCT241736.

Internal tandem duplication of FLT3 (FLT3-ITD) is one of the most common somatic mutations in acute myeloid leukemia (AML); it causes constitutive activation of FLT3 kinase and is associated with high relapse rates and poor survival. Small-molecule inhibition of FLT3 represents an attractive therapeutic strategy for this subtype of AML, although resistance from secondary FLT3 tyrosine kinase domain (FLT3-TKD) mutations is an emerging clinical problem. CCT241736 is an orally bioavailable, selective, and potent dual inhibitor of FLT3 and Aurora kinases.

Correction: Signalling involving MET and FAK supports cell division independent of the activity of the cell cycle-regulating CDK4/6 kinases.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

High Proliferation Rate and a Compromised Spindle Assembly Checkpoint Confers Sensitivity to the MPS1 Inhibitor BOS172722 in Triple-Negative Breast Cancers.

BOS172722 (CCT289346) is a highly potent, selective, and orally bioavailable inhibitor of spindle assembly checkpoint kinase MPS1. BOS172722 treatment alone induces significant sensitization to death, particularly in highly proliferative triple-negative breast cancer (TNBC) cell lines with compromised spindle assembly checkpoint activity. BOS172722 synergizes with paclitaxel to induce gross chromosomal segregation defects caused by MPS1 inhibitor-mediated abrogation of the mitotic delay induced by paclitaxel treatment.

Signalling involving MET and FAK supports cell division independent of the activity of the cell cycle-regulating CDK4/6 kinases.

Deregulation of cyclin-dependent kinases 4 and 6 (CDK4/6) is highly prevalent in cancer; yet, inhibitors against these kinases are currently used only in restricted tumour contexts. The extent to which cancers depend on CDK4/6 and the mechanisms that may undermine such dependency are poorly understood. Here, we report that signalling engaging the MET proto-oncogene receptor tyrosine kinase/focal adhesion kinase (FAK) axis leads to CDK4/6-independent CDK2 activation, involving as critical mechanistic events loss of the CDKI p21 and gain of its regulator, the ubiquitin ligase subunit SKP2.

ALK2 inhibitors display beneficial effects in preclinical models of mutant diffuse intrinsic pontine glioma.

Diffuse intrinsic pontine glioma (DIPG) is a lethal childhood brainstem tumour, with a quarter of patients harbouring somatic mutations in , encoding the serine/threonine kinase ALK2. Despite being an amenable drug target, little has been done to-date to systematically evaluate the role of in DIPG, nor to screen currently available inhibitors in patient-derived tumour models. Here we show the dependence of DIPG cells on the mutant receptor, and the preclinical efficacy of two distinct chemotypes of ALK2 inhibitor in vitro and in vivo.

Binding to an Unusual Inactive Kinase Conformation by Highly Selective Inhibitors of Inositol-Requiring Enzyme 1α Kinase-Endoribonuclease.

A series of imidazo[1,2- b]pyridazin-8-amine kinase inhibitors were discovered to allosterically inhibit the endoribonuclease function of the dual kinase-endoribonuclease inositol-requiring enzyme 1α (IRE1α), a key component of the unfolded protein response in mammalian cells and a potential drug target in multiple human diseases. Inhibitor optimization gave compounds with high kinome selectivity that prevented endoplasmic reticulum stress-induced IRE1α oligomerization and phosphorylation, and inhibited endoribonuclease activity in human cells. X-ray crystallography showed the inhibitors to bind to a previously unreported and unusually disordered conformation of the IRE1α kinase domain that would be incompatible with back-to-back dimerization of the IRE1α protein and activation of the endoribonuclease function.

Metabolic biomarkers of response to the AKT inhibitor MK-2206 in pre-clinical models of human colorectal and prostate carcinoma.

Background: AKT is commonly overexpressed in tumours and plays an important role in the metabolic reprogramming of cancer. We have used magnetic resonance spectroscopy (MRS) to assess whether inhibition of AKT signalling would result in metabolic changes that could potentially be used as biomarkers to monitor response to AKT inhibition.

Methods: Cellular and metabolic effects of the allosteric AKT inhibitor MK-2206 were investigated in HT29 colon and PC3 prostate cancer cells and xenografts using flow cytometry, immunoblotting, immunohistology and MRS.

Introduction of a Methyl Group Curbs Metabolism of Pyrido[3,4- d]pyrimidine Monopolar Spindle 1 (MPS1) Inhibitors and Enables the Discovery of the Phase 1 Clinical Candidate N-(2-Ethoxy-4-(4-methyl-4 H-1,2,4-triazol-3-yl)phenyl)-6-methyl- N-neopentylpyrido[3,4- d]pyrimidine-2,8-diamine (BOS172722).

Monopolar spindle 1 (MPS1) occupies a central role in mitosis and is one of the main components of the spindle assembly checkpoint. The MPS1 kinase is an attractive cancer target, and herein, we report the discovery of the clinical candidate BOS172722. The starting point for our work was a series of pyrido[3,4- d]pyrimidine inhibitors that demonstrated excellent potency and kinase selectivity but suffered from rapid turnover in human liver microsomes (HLM).

Correction to: An in vitro and in vivo study of the combination of the heat shock protein inhibitor 17-allylamino-17-demethoxygeldanamycin and carboplatin in human ovarian cancer models.

The corresponding author of this article has informed us of concerns about the immunoblots in Fig. 2 which were carried out in the collaborating laboratory of Professor Ann Jackman.

Evaluating Imaging Biomarkers of Acquired Resistance to Targeted EGFR Therapy in Xenograft Models of Human Head and Neck Squamous Cell Carcinoma.

Overexpression of EGFR is a negative prognostic factor in head and neck squamous cell carcinoma (HNSCC). Patients with HNSCC who respond to EGFR-targeted tyrosine kinase inhibitors (TKIs) eventually develop acquired resistance. Strategies to identify HNSCC patients likely to benefit from EGFR-targeted therapies, together with biomarkers of treatment response, would have clinical value.

Patient-derived organoids model treatment response of metastatic gastrointestinal cancers.

Patient-derived organoids (PDOs) have recently emerged as robust preclinical models; however, their potential to predict clinical outcomes in patients has remained unclear. We report on a living biobank of PDOs from metastatic, heavily pretreated colorectal and gastroesophageal cancer patients recruited in phase 1/2 clinical trials. Phenotypic and genotypic profiling of PDOs showed a high degree of similarity to the original patient tumors.

HSF1 Is Essential for Myeloma Cell Survival and A Promising Therapeutic Target.

Myeloma is a plasma cell malignancy characterized by the overproduction of immunoglobulin, and is therefore susceptible to therapies targeting protein homeostasis. We hypothesized that heat shock factor 1 (HSF1) was an attractive therapeutic target for myeloma due to its direct regulation of transcriptional programs implicated in both protein homeostasis and the oncogenic phenotype. Here, we interrogate HSF1 as a therapeutic target in myeloma using bioinformatic, genetic, and pharmacologic means.

MIR21 Drives Resistance to Heat Shock Protein 90 Inhibition in Cholangiocarcinoma.

Background & Aims: Cholangiocarcinomas (CCA) are resistant to chemotherapy, so new therapeutic agents are needed. We performed a screen to identify small-molecule compounds that are active against CCAs. Levels of microRNA 21 (MIR21 or miRNA21) are increased in CCAs.

Value of combining dynamic contrast enhanced ultrasound and optoacoustic tomography for hypoxia imaging.

Optoacoustic imaging (OAI) can detect haemoglobin and assess its oxygenation. However, the lack of a haemoglobin signal need not indicate a lack of perfusion. This study uses a novel method to assist the co-registration of optoacoustic images with dynamic contrast enhanced ultrasound (DCE-US) images to demonstrate, in preclinical tumour models, the value of combining haemoglobin imaging with a perfusion imaging method, showing that a lack of a haemoglobin signal does not necessarily indicate an absence of perfusion.

Functional imaging and circulating biomarkers of response to regorafenib in treatment-refractory metastatic colorectal cancer patients in a prospective phase II study.

Objective: Regorafenib demonstrated efficacy in patients with metastatic colorectal cancer (mCRC). Lack of predictive biomarkers, potential toxicities and cost-effectiveness concerns highlight the unmet need for better patient selection.

Design: Patients with mutant mCRC with biopsiable metastases were enrolled in this phase II trial.

Evaluation of the Response of Intracranial Xenografts to VEGF Signaling Inhibition Using Multiparametric MRI.

Vascular endothelial growth factor A (VEGF-A) is considered one of the most important factors in tumor angiogenesis, and consequently, a number of therapeutics have been developed to inhibit VEGF signaling. Therapeutic strategies to target brain malignancies, both primary brain tumors, particularly in pediatric patients, and metastases, are lacking, but targeting angiogenesis may be a promising approach. Multiparametric MRI was used to investigate the response of orthotopic SF188 pediatric glioblastoma xenografts to small molecule pan-VEGFR inhibitor cediranib and the effects of both cediranib and cross-reactive human/mouse anti-VEGF-A antibody B20-4.

Modulation of Plasma Metabolite Biomarkers of the MAPK Pathway with MEK Inhibitor RO4987655: Pharmacodynamic and Predictive Potential in Metastatic Melanoma.

MAPK pathway activation is frequently observed in human malignancies, including melanoma, and is associated with sensitivity to MEK inhibition and changes in cellular metabolism. Using quantitative mass spectrometry-based metabolomics, we identified in preclinical models 21 plasma metabolites including amino acids, propionylcarnitine, phosphatidylcholines, and sphingomyelins that were significantly altered in two B-RAF-mutant melanoma xenografts and that were reversed following a single dose of the potent and selective MEK inhibitor RO4987655. Treatment of non-tumor-bearing animals and mice bearing the PTEN-null U87MG human glioblastoma xenograft elicited plasma changes only in amino acids and propionylcarnitine.

Coupling between the TRPC3 ion channel and the NCX1 transporter contributed to VEGF-induced ERK1/2 activation and angiogenesis in human primary endothelial cells.

It has been previously demonstrated that the bi-directional transporter Na/Ca exchanger (NCX) working in the reverse (Ca-influx) - mode promotes the activation of ERK1/2 in response to the key pro-angiogenic cytokine VEGF in human endothelial cells (ECs). However, the molecular event(s) that elicit NCX reversal in VEGF-stimulated ECs remain unclear. Here we investigated whether Na influx via the diacylglycerol (DAG) - activated non-selective cation channel TRPC3 was functionally associated with NCX and whether its activity was required for VEGF-induced ERK1/2 activation and angiogenesis.

High ASMA Fibroblasts and Low Cytoplasmic HMGB1 Breast Cancer Cells Predict Poor Prognosis.

Introduction: The influence of cancer-associated fibroblasts (CAFs) and high mobility group box 1 (HMGB1) has been recognized in several cancers, although their roles in breast cancer are unclear. The present study aimed to determine the levels and prognostic significance of α-smooth muscle actin-positive (ASMA) CAFs, plus HMGB1 and receptor for advanced glycation end products (RAGE) in cancer cells.

Materials And Methods: A total of 127 breast samples, including 96 malignant and 31 benign, were examined for ASMA, HMGB1, and RAGE by immunohistochemistry.