The combination of gefitinib and RAD001 inhibits growth of HER2 overexpressing breast cancer cells and tumors irrespective of trastuzumab sensitivity

<p>Abstract</p> <p>Background</p> <p>HER2-positive breast cancers exhibit high rates of innate and acquired resistance to trastuzumab (TZ), a HER2-directed antibody used as a first line treatment for this disease. TZ resistance may in part be mediated by frequent co-expression of EGFR and by sustained activation of the mammalian target of rapamycin (mTOR) pathway. Here, we assessed feasibility of combining the EGFR inhibitor gefitinib and the mTOR inhibitor everolimus (RAD001) for treating HER2 overexpressing breast cancers with different sensitivity to TZ.</p> <p>Methods</p> <p>The gefitinib and RAD001 combination was broadly evaluated in TZ sensitive (SKBR3 and MCF7-HER2) and TZ resistant (JIMT-1) breast cancer models. The effects on cell growth were measured in cell based assays using the fixed molar ratio design and the median effect principle. <it>In vivo </it>studies were performed in Rag2M mice bearing established tumors. Analysis of cell cycle, changes in targeted signaling pathways and tumor characteristics were conducted to assess gefitinib and RAD001 interactions.</p> <p>Results</p> <p>The gefitinib and RAD001 combination inhibited cell growth <it>in vitro </it>in a synergistic fashion as defined by the Chou and Talalay median effect principle and increased tumor xenograft growth delay. The improvement in therapeutic efficacy by the combination was associated <it>in vitro </it>with cell line dependent increases in cytotoxicity and cytostasis while treatment <it>in vivo </it>promoted cytostasis. The most striking and consistent therapeutic effect of the combination was increased inhibition of the mTOR pathway (<it>in vitro </it>and <it>in vivo</it>) and EGFR signaling <it>in vivo </it>relative to the single drugs.</p> <p>Conclusions</p> <p>The gefitinib and RAD001 combination provides effective control over growth of HER2 overexpressing cells and tumors irrespective of the TZ sensitivity status.</p

Biocompatibility of orthopaedic implants on bone forming cells

Abstract Reindeer antler was studied for its possible use as a bone implant material. A molecular biological study showed that antler contains a growth factor promoting bone formation. Ectopic bone formation assay showed that antler is not an equally effective inducer as allogenic material. Ectopic bone formation assay was optimised for biocompatibility studies of orthopaedic NiTi implants. Ti-6Al-4V and stainless steel were used as reference materials. The assay showed differences in bone mineral densities, with superior qualities in NiTi. The rate of endochondral ossification varied between the implants, NiTi ossicles had larger cartilage and bone areas than ossicles of the two other materials. The cytocompatibility of NiTi was studied with three different methods. Cell viability, cell adhesion and TGF-β1 concentration were assessed in ROS-17/2.8 cell cultures. Cells grown on NiTi had better viability than cells grown on pure nickel or stainless steel. Cell attachment on the materials was studied with paxillin staining of focal contacts. The number of focal contacts was clearly higher in cells grown on NiTi than in cells grown on pure titanium, pure nickel or stainless steel. TGF-β1 concentration was measured with ELISA. The results showed that there was only some minor variation between NiTi, pure titanium and stainless steel. Nickel showed a lower TGF-β1 concentration. Taken together, these results suggest that NiTi is well tolerated by ROS-17/2.8 cells. The cytocompatibility of stainless steel is not so good as that of NiTi. The same tests were used to study the effects of the surface roughness of the implant on cytocompatibility. Three different surface roughness grades were compared in cell cultures on NiTi and titanium alloy discs. Titanium alloy was subjected to two different heat treatments, to compare the effects of the treatments on cytocompatibility. The studies showed that NiTi had a lesser impact on cell viability and attachment than titanium alloy. Further, rough NiTi was found to be a better tolerated surface than the others. In this study, heat treatment of titanium alloy at +850° C did not interfere with cell viability or attachment, as did the +1050° C treatment of the alloy. On the contrary, TGF-β1 concentrations decreased on the +850° C treated alloy and were approximately same on the +1050° C treated alloy and on NiTi

Setting Goals to Reduce Cardiovascular Risk : A Retrospective Chart Review of a Pharmacist-Led Initiative in the Workplace

Background: Cardiovascular diseases (CVD) are the second leading cause of death in Canada with many modifiable risk factors. Pharmacists at a Canadian university delivered a novel CVD risk management program, which included goal-setting and medication management. Aim: This study aimed to describe what CVD prevention goals are composed of in a workplace CVD risk reduction program, and how might these goals change over time. Methods: A longitudinal, descriptive qualitative study using a retrospective chart review of clinical care plans for 15 patients enrolled in a CVD prevention program. Data across 6 visits were extracted from charts (n = 5413 words) recorded from May 2019–November 2020 and analyzed using quantitative content analysis and descriptive statistics. Results: Behavioural goals were most popular among patients and were more likely to change over the 12-month follow-up period, compared to health measure goals. Behavioural goals included goals around diet, physical activity (PA), smoking, medication, sleep and alcohol; health measure goals centered on weight measures, blood pressure (BP) and blood lipid levels. The most common behavioural goals set by patients were for diet (n = 11) and PA (n = 9). Over time, goals around PA, medication, alcohol and weight were adapted while others were added (e.g. diet) and some only continued. Patients experienced a number of barriers to their goal(s) which informed how they adapted their goal(s). These included environmental limitations (including COVID-19) and work-related time constraints. Conclusions: This study found CVD goal-setting in the pharmacist-led workplace wellness program was complex and evolved over time, with goals added and/or adapted. More detailed qualitative research could provide further insights into the patient-provider goal-setting experience in workplace CVD prevention.Medicine, Faculty ofPharmaceutical Sciences, Faculty ofOther UBCEmergency Medicine, Department ofReviewedFacultyResearcherGraduat

Cytogenetic characterization and gene expression profiling of the trastuzumab-resistant breast cancer cell line JIMT-1.

Resistance to the HER-2 targeting drug trastuzumab can be observed clinically, but the lack of suitable experimental models hampers studies of resistance mechanisms. We characterized a HER-2–positive carcinoma cell line (JIMT-1) derived from a 62-year-old breast cancer patient which was clinically resistant to trastuzumab. Multicolor fluorescence in situ hybridization revealed a complex hyperdiploid karyotype with numerous marker chromosomes and unbalanced translocations. Comparative genomic hybridization (CGH) revealed numerous regions of copy number aberration (CNA). Further analysis by array CGH identified 27 regions of CNA (16 amplified, 11 deleted). Thirty-eight percent of the genes in the amplified regions were overexpressed, compared to only 9% in regions of normal copy number ratios (CNR). Accordingly, 26% of the genes in the deleted regions were underexpressed, compared to 10% in regions of normal CNR. Most amplified and overexpressed genes were located on chromosome 1 as well as on 8q, 12q14.1, 17q11not, vert, similarq21, and 20q13. In 17q11not, vert, similarq21, we identified two separate amplicons, the HER-2 amplicon and a previously unreported amplicon at 17q21.31. Several aberrant genes are implicated in cancer development (e.g., JUN, CDK4, and SLUG protooncogenes, as well as the drug/hormone–metabolizing genes GSTM1 and CYP24). We conclude that cytogenetic and expression profiling of JIMT-1 revealed several new features that need further characterization and may shed light on trastuzumab resistance

Induction of Autophagy Is an Early Response to Gefitinib and a Potential Therapeutic Target in Breast Cancer

Gefitinib (Iressa®, ZD1839) is a small molecule inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase. We report on an early cellular response to gefitinib that involves induction of functional autophagic flux in phenotypically diverse breast cancer cells that were sensitive (BT474 and SKBR3) or insensitive (MCF7-GFPLC3 and JIMT-1) to gefitinib. Our data show that elevation of autophagy in gefitinib-treated breast cancer cells correlated with downregulation of AKT and ERK1/2 signaling early in the course of treatment. Inhibition of autophagosome formation by BECLIN-1 or ATG7 siRNA in combination with gefitinib reduced the abundance of autophagic organelles and sensitized SKBR3 but not MCF7-GFPLC3 cells to cell death. However, inhibition of the late stage of gefitinib-induced autophagy with hydroxychloroquine (HCQ) or bafilomycin A1 significantly increased (p&lt;0.05) cell death in gefitinib-sensitive SKBR3 and BT474 cells, as well as in gefitinib-insensitive JIMT-1 and MCF7-GFPLC3 cells, relative to the effects observed with the respective single agents. Treatment with the combination of gefitinib and HCQ was more effective (p&lt;0.05) in delaying tumor growth than either monotherapy (p&gt;0.05), when compared to vehicle-treated controls. Our results also show that elevated autophagosome content following short-term treatment with gefitinib is a reversible response that ceases upon removal of the drug. In aggregate, these data demonstrate that elevated autophagic flux is an early response to gefitinib and that targeting EGFR and autophagy should be considered when developing new therapeutic strategies for EGFR expressing breast cancers