HER2 mediates clinical resistance to the KRASG12C inhibitor sotorasib, which is overcome by co-targeting SHP2.

INTRODUCTION: Mutant RAS guanosine triphosphate hydrolases (GTPases) are key oncogenic drivers in many cancers. The KRASG12C variant has recently become targetable by a new drug class specifically locking KRASG12C in its inactive guanosine diphosphate (GDP)-bound state. Clinical activity was demonstrated in patients with advanced lung cancers harbouring KRASG12C mutations but was limited by the development of resistance. METHODS: A biopsy from progressing lung cancer of a patient treated with the KRASG12C inhibitor sotorasib was obtained, and the underlying resistance factors were analysed. Mechanistic studies were performed in vitro and in vivo to uncover strategies to overcome resistance to KRASG12C inhibition. RESULTS: We demonstrated acquisition of HER2 copy number gain and KRASG12C mutation retention in the post-progression biopsy. To explore HER2 gain as the relevant resistance mechanism, we generated KRASG12C lung cancer models overexpressing HER2. MAPK pathway signalling remained active despite KRASG12C inhibitor treatment. Combined pharmacological inhibition of KRASG12C and SHP2 synergistically overcame HER2-mediated resistance in vitro and in vivo. CONCLUSIONS: These findings establish HER2 copy number gain as a clinically relevant mechanism of resistance to pharmacological KRASG12C inhibition that can be overcome by co-targeting SHP2.

HDAC inhibition synergizes with ALK inhibitors to overcome resistance in a novel ALK mutated lung adenocarcinoma model.

OBJECTIVES: Somatic chromosomal rearrangements resulting in ALK fusion oncogenes are observed in 3-7 % of lung adenocarcinomas. ALK tyrosine kinase inhibitors (ALKi) induce initially response, however, various resistance mechanisms limit their efficacy. Novel therapeutic approaches are of utmost importance to tailor these targeted therapies. MATERIALS AND METHODS: A synchronous ALK-rearranged and mutated lung cancer cell line pair was established from malignant pleural effusion (PF240-PE) and carcinosis (PF240-PC) at time of ALKi resistance. Immunohistochemistry, FISH and sequencing were performed in pre- and post-treatment tumors and in both cell lines. Differentiation markers were measured by immunoblot. Viability was tested following treatment with ALKi and/or a pan-HDAC inhibitor. Additionally, a novel treatment-naïve ALK-rearranged cell line served as control. In vivo tumorigenicity was evaluated in subcutaneous xenografts. RESULTS: Two distinct resistance mutations were identified in different carcinosis tissues at time of resistance, the previously described resistance mutation L1152R and the hitherto uncharacterized E1161K. Strikingly, PF240-PC cells carried E1161K and PF240-PE cells harbored L1152R. Immunohistochemistry and immunoblot identified epithelial-to-mesenchymal transition markers upregulated following ALKi resistance development both in carcinosis tissues and cell lines. While both lines grew as xenografts, they differed in morphology, migration, in vivo growth and sensitivity to ALKi in vitro. Strikingly, the combination of ALKi with SAHA yielded strong synergism. CONCLUSION: Using a patient-derived ALKi resistant lung cancer model we demonstrated the synergism of HDAC and ALK inhibition. Furthermore, our findings provide strong evidence for intratumoral heterogeneity under targeted therapy and highlight the importance of site-specific mutational analysis.

Fluorescence multispectral imaging-based diagnostic system for atherosclerosis.

BACKGROUND: Composition of atherosclerotic arterial walls is rich in lipids such as cholesterol, unlike normal arterial walls. In this study, we aimed to utilize this difference to diagnose atherosclerosis via multispectral fluorescence imaging, which allows for identification of fluorescence originating from the substance in the arterial wall. METHODS: The inner surface of extracted arteries (rabbit abdominal aorta, human coronary artery) was illuminated by 405 nm excitation light and multispectral fluorescence images were obtained. Pathological examination of human coronary artery samples were carried out and thickness of arteries were calculated by measuring combined media and intima thickness. RESULTS: The fluorescence spectra in atherosclerotic sites were different from those in normal sites. Multiple regions of interest (ROI) were selected within each sample and a ratio between two fluorescence intensity differences (where each intensity difference is calculated between an identifier wavelength and a base wavelength) from each ROI was determined, allowing for discrimination of atherosclerotic sites. Fluorescence intensity and thickness of artery were found to be significantly correlated. CONCLUSIONS: These results indicate that multispectral fluorescence imaging provides qualitative and quantitative evaluations of atherosclerosis and is therefore a viable method of diagnosing the disease.

Effect of aerobic exercise training on chinese population with mild to moderate depression in Hong Kong.

Background. Exercise has been suggested to be a viable treatment for depression. This study investigates the effect of supervised aerobic exercise training on depressive symptoms and physical performance among Chinese patients with mild to moderate depression in early in-patient phase. Methods. A randomized repeated measure and assessor-blinded study design was used. Subjects in aerobic exercise group received 30 minutes of aerobic training, five days a week for 3 weeks. Depressive symptoms (MADRS and C-BDI) and domains in physical performance were assessed at baseline and program end. Results. Subjects in aerobic exercise group showed a more significant reduction in depressive scores (MADRS) as compared to control (between-group mean difference = 10.08 ± 9.41; P = 0.026) after 3 weeks training. The exercise group also demonstrated a significant improvement in flexibility (between-group mean difference = 4.4 ± 6.13; P = 0.02). Limitations. There was lack of longitudinal followup to examine the long-term effect of aerobic exercise on patients with depression. Conclusions. Aerobic exercise in addition to pharmacological intervention can have a synergistic effect in reducing depressive symptoms and increasing flexibility among Chinese population with mild to moderate depression. Early introduction of exercise training in in-patient phase can help to bridge the gap of therapeutic latency of antidepressants during its nonresponse period.

Persistent Helicobacter pylori specific Th17 responses in patients with past H. pylori infection are associated with elevated gastric mucosal IL-1ß.

BACKGROUND: Ongoing Helicobacter pylori (HP) infection triggers a chronic active gastritis. Eradicating HP reduces gastric inflammation, but does not eliminate it. We sought to characterize this persistent gastritis, and demonstrate the persistence of HP-specific Th17 responses in individuals previously infected with HP but who no longer had evidence of ongoing infection. METHODOLOGY/PRINCIPAL FINDINGS: Study subjects were divided into 3 groups 55 individuals had active HP infection (group A), 41 were diagnosed with previous HP infection (group P), and 59 were naïve to HP (group N). Blood and gastric tissue were obtained with written informed consent from all subjects, and immune responses were evaluated using flow cytometry, semi-quantitative real time PCR, immunofluorescent staining, ELISA, and multiplex cytometric bead array for cytokine quantification. Elevated IL-17A responses were observed in patients from group A compared to group N. Interestingly, IL-17A responses remained persistently elevated in the blood and gastric mucosa of individuals from group P, despite the absence of ongoing HP infection. Using purified CD4(+) T cells as effectors and antibodies that blocked antigen presentation by MHC Class II, we showed that these persistent IL-17A responses were mediated primarily by HP-specific Th17 cells, rather than other immune cells that have also been described to secrete IL-17A. Gastric mucosal IL-1ß levels were also persistently elevated in group P, and neutralisation of IL-1ß reduced the HP-specific IL-17A response of purified CD4(+) T cells to autologous HP-pulsed antigen presenting cells in vitro, suggesting a functional association between IL-1ß and the persistent Th17 response in group P patients. CONCLUSIONS/SIGNIFICANCE: Despite lack of ongoing HP infection, HP-specific Th17 cells persist in the blood and gastric mucosa of individuals with past HP infection. We speculate that this persistent inflammation might contribute to gastric mucosal pathology, for example, persistent increased gastric cancer risk despite eradication of HP.