Experimental Evidence of t_{2g} Electron-Gas Rashba Interaction Induced by Asymmetric Orbital Hybridization

We report the control of Rashba spin-orbit interaction by tuning asymmetric hybridization between Ti orbitals at the LaAlO_{3}/SrTiO_{3} interface. This asymmetric orbital hybridization is modulated by introducing a LaFeO_{3} layer between LaAlO_{3} and SrTiO_{3}, which alters the Ti-O lattice polarization and traps interfacial charge carriers, resulting in a large Rashba spin-orbit effect at the interface in the absence of an external bias. This observation is verified through high-resolution electron microscopy, magnetotransport and first-principles calculations. Our results open hitherto unexplored avenues of controlling Rashba interaction to design next-generation spin orbitronics.

Margetuximab with retifanlimab as first-line therapy in HER2+/PD-L1+ unresectable or metastatic gastroesophageal adenocarcinoma: MAHOGANY cohort A

BACKGROUND

Human epidermal growth factor receptor 2 (HER2)-positive metastatic gastric and gastroesophageal adenocarcinoma (GEA) is globally treated with chemotherapy plus trastuzumab. Novel therapeutic strategies strive to not only optimize efficacy, but also limit toxicities. In MAHOGANY cohort A, margetuximab, an Fc-engineered, anti-HER2 monoclonal antibody (mAb) was combined with retifanlimab, an anti-programmed cell death protein 1 mAb, in the first-line HER2-positive/programmed death-ligand 1 (PD-L1)-positive GEA.

PATIENTS AND METHODS

MAHOGANY cohort A part 1 is a single-arm trial to evaluate margetuximab plus retifanlimab in patients with HER2 immunohistochemistry 3+, PD-L1-positive (combined positive score ≥1%), and non-microsatellite instability-high tumors. Primary objectives for cohort A were safety/tolerability and the confirmed objective response rate (ORR).

RESULTS

As of 3 August 2021, 43 patients were enrolled and received margetuximab/retifanlimab. Nine grade 3 treatment-related adverse events (TRAEs) were reported in eight (18.6%) patients and eight serious TRAEs in seven (16.3%) patients. There were no grade 4/5 TRAEs. Three patients discontinued margetuximab/retifanlimab because of immune-related adverse events. The ORR by independent assessment was 53% [21/40 (95% confidence interval (CI) 36.1-68.5)], with a median duration of response of 10.3 months (95% CI 4.6-not evaluable); disease control rate was 73% [29/40 (95% CI 56.1-85.4)]. The study sponsor discontinued the study in advance of the planned enrollment when it became apparent that the study design would no longer meet the requirements for drug approval because of recent advances in the treatment of GEA.

CONCLUSIONS

The chemotherapy-free regimen of combined margetuximab/retifanlimab as first-line treatment in double biomarker-selected patients demonstrated a favorable toxicity profile compared with historical outcomes using chemotherapy plus trastuzumab. The ORR observed in this study compares favorably versus ORR observed with other chemotherapy-free approaches.

The fluctuation-dissipation measurement instrument at the Linac Coherent Light Source

The development of new modes at x-ray free electron lasers has inspired novel methods for studying fluctuations at different energies and timescales. For closely spaced x-ray pulses that can be varied on ultrafast time scales, we have constructed a pair of advanced instruments to conduct studies targeting quantum materials. We first describe a prototype instrument built to test the proof-of-principle of resonant magnetic scattering using ultrafast pulse pairs. This is followed by a description of a new endstation, the so-called fluctuation-dissipation measurement instrument, which was used to carry out studies with a fast area detector. In addition, we describe various types of diagnostics for single-shot contrast measurements, which can be used to normalize data on a pulse-by-pulse basis and calibrate pulse amplitude ratios, both of which are important for the study of fluctuations in materials. Furthermore, we present some new results using the instrument that demonstrates access to higher momentum resolution.

[The value of high-definition intelligent endoscopy combined with stroboscopy in the diagnosis and treatment of vocal cord leukoplakia]

Objective: To evaluate the clinical value of high-definition intelligent endoscopy (iSCAN) combined with stroboscopy in identifying vocal cord leukoplakia. Methods: Seventy-nine patients with vocal cord leukoplakia who underwent CO₂ laser laryngeal microsurgery and diagnosed by histopathology were recruited between October 2020 to August 2021. The morphological features, microvascular morphology and mucosal waves were observed by stroboscope; SPSS 20.0 software was used for statistical analysis. Results: There were 79 patients with a total of 119 lesions (56 on left and 63 on right).Pathological examination showed that 51 sides of the vocal cords were malignant lesions (severe dysplasia, carcinoma in situ and invasive carcinoma), and 68 sides were benign lesions.Under stroboscopy, 69 sides of mucosal wave were normal or slightly decreased, and 50 sides were severely decreased or disappeared.The decrease degree of mucosal wave was positively correlated with malignant lesions (ρ=0.687, P<0.001).Under iSCAN endoscopy, there was a positive correlation between the morphological changes of microvessels at the lesion site (vertical) and the malignant lesion (ρ=0.687, P<0.001).Univariate analysis showed that lesion size, thickness, uneven color, granular elevation, peripheral erythema and asymmetry were positively correlated with malignant lesions (ρ=0.530, 0.401, 0.538, 0.315, 0.497, 0.281, P<0.05).Logistic regression analysis showed that the risk of pathological malignancy with large lesions was 5.437 times higher than those of small lesions, the vertical vascular changes under iSCAN were 8.711 times higher than that of normal vascular morphology, and the severe reduction or disappearance of mucosal waves was 9.12 times higher than that of normal or mild reduction of mucosal waves. Conclusion: ISCAN can be combined with staphyloscopy to comprehensively observe and evaluate the changes of vocal cord morphology, submucosal microvessels and mucosal wave of vocal cord in patients with vocal cord leukoplosis, thus improving the ability to distinguish benign and malignant lesions.

Tislelizumab versus chemotherapy as second-line treatment of advanced or metastatic esophageal squamous cell carcinoma (RATIONALE 302): impact on health-related quality of life

Background

RATIONALE 302 (NCT03430843) an open-label, phase III study of second-line treatment of advanced/metastatic esophageal squamous cell carcinoma (ESCC), reported that tislelizumab, relative to investigator-chosen chemotherapy (ICC), was associated with improvements in overall survival and a favorable safety profile. This study assessed the health-related quality of life (HRQoL) and ESCC-related symptoms of patients in RATIONALE 302.

Methods

Adults with advanced/metastatic ESCC whose disease progressed following prior systemic therapy were randomized 1 : 1 to receive either tislelizumab or ICC (paclitaxel, docetaxel, or irinotecan). HRQoL was measured using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 items (EORTC QLQ-C30), the EORTC Quality of Life Questionnaire Oesophageal Cancer Module 18 items (QLQ-OES18), and the EuroQoL Five-Dimensions Five-Levels (EQ-5D-5L) visual analogue scale. Mixed effect modeling for repeated measurements examined changes from baseline to weeks 12 and 18. The Kaplan–Meier method was used to examine time to deterioration.

Results

Overall, 512 patients were randomized to tislelizumab (n = 256) or ICC (n = 256). The tislelizumab arm maintained QLQ-C30 global health status/quality whereas the ICC arm worsened at week 12 {difference in least square (LS) mean change: 5.8 [95% confidence interval (CI): 2.0-9.5], P = 0.0028} and week 18 [difference in LS mean change: 8.1 (95% CI: 3.4-12.8), P = 0.0008]. Physical functioning (week 18) and fatigue (weeks 12 and 18) worsened less in the tislelizumab compared with the ICC arm. The tislelizumab arm improved in reflux symptoms, whereas the ICC worsened at week 12 [difference in LS mean change: −4.1 (95% CI: −7.6 to −0.6), P = 0.0229]. The visual analogue scale remained consistent in the tislelizumab arm whereas it worsened in the ICC arm. The hazard of time to deterioration was lower in tislelizumab patients compared with ICC for physical functioning and reflux.

Conclusions

HRQoL, including fatigue symptoms and physical functioning, was maintained in patients with advanced or metastatic ESCC receiving tislelizumab compared with ICC-treated patients. These results provide additional support for the benefits of tislelizumab in this patient population.

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Global health status and HRQoL remained consistent in the tislelizumab arm whereas the ICC arm experienced worsening.

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Fatigue and physical functioning worsened in both arms; however, the worsening was greater in the ICC arm.

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The tislelizumab arm was at lower risk of reaching the threshold for worsening in physical functioning and reflux.

POS0476 THE NUCLEAR RECEPTOR TR4 ORCHESTRATES CYTOSKELETAL ORGANIZATION IN A Gα12/ROCK-DEPENDENT MANNER TO PROMOTE MYOFIBROBLAST DIFFERENTIATION AND TISSUE FIBROSIS IN SYSTEMIC SCLEROSIS

Background

Nuclear receptors (NR) are a family of transcription factors. Several members of the NR family are candidates for targeted intervention in inflammatory and fibrotic diseases (1-2). Testicular receptor 4 (TR4), also known as Nr2c2, has been shown to regulate fundamental cellular processes such as differentiation, proliferation and growth factor signaling (3-4). However, its role in fibrotic diseases has not been investigated so far.

Objectives

The aim of the present study was to characterize the role of TR4 in the pathogenesis of fibrotic tissue remodeling in SSc and to interrogate its underlying mechanism.

Methods

Expression of TR4 was quantified by RT-PCR, Western blot and immunofluorescence. The effects of TR4 knockdown on collagen production and myofibroblast differentiation were analyzed in cultured human fibroblasts and in three mouse models with fibroblast-specific knockout of TR4. RNA sequencing was performed in TGFβ-stimulated human dermal fibroblasts transfected with TR4 siRNA or non-targeting siRNA. The implication of TR4 in cytoskeleton regulation was analyzed by ROCK activity assays, stress fiber formation and quantification of the ratio of filamentous (F)-actin/ globular (G)-actin. The functional role of ROCK and Gα12 was analyzed using small molecule inhibitors and siRNA, respectively.

Results

TR4 expression was upregulated in fibroblasts in the skin of SSc patients and fibrotic mouse models. The expression of TR4 was upregulated in a TGFβ- and SMAD3-dependent manner. TR4 knockdown inhibited TGFβ-induced myofibroblast differentiation and collagen release, whereas overexpression of TR4 promoted fibroblast activation. Fibroblastspecific knockout of TR4 ameliorated experimental dermal fibrosis induced by bleomycin, adTBR and in sclGVHD with decreases in dermal thickening, myofibroblast counts and hydroxyproline content. The RNASeq of TR4 knockdown fibroblasts stimulated with TGFβ identified 651 differentially expressed genes as compared to control fibroblasts. Differentially expressed genes included central profibrotic genes such as ACTA2, COL3A1, CCL12. gProfiler enrichment analysis of the TR4-DEGs revealed enrichment of multiple GO, GSEA and Reactome terms related to ECM release, cytoskeleton organization and Rho GTPases activity. Indeed, knockdown of TR4 ameliorated the induction of ROCK activity by TGFβ stimulation and reduced the shift in the ratio from globular (G) actin to filamentous (F) actin. Knockdown of TR4 strongly reduced the expression of the G-protein alpha-12 (Gα12). ROCK inhibition by Y27632 or knockdown of Gα12 inhibited the induction of αSMA and stress fiber formation induced by overexpression of TR4.

Conclusion

TR4 is upregulated in SSc in a TGFβ-dependent manner to promote fibroblast activation. Inhibition of TR4 interferes with TGFβ-induced activation of ROCK, prevents cytoskeletal remodeling and fibroblast-to-myofibroblast transition and ameliorates experimental fibrosis. As nuclear receptors are common targets for therapeutic intervention, TR4 may offer potential for antifibrotic therapies.

References

[1]Avouac J, Palumbo-Zerr K, et al. The nuclear receptor constitutive androstane receptor/NR1I3 enhances the profibrotic effects of transforming growth factor beta and contributes to the development of experimental dermal fibrosis. Arthritis Rheumatol. 2014;66(11):3140-50.

[2]Palumbo-Zerr K, Zerr P, et al. Orphan nuclear receptor NR4A1 regulates transforming growth factor-beta signaling and fibrosis. Nat Med. 2015;21(2):150-8.

[3]Bookout AL, Jeong Y, Downes M, Yu RT, Evans RM, Mangelsdorf DJ. Anatomical profiling of nuclear receptor expression reveals a hierarchical transcriptional network. Cell. 2006;126(4):789-99.

[4]Simandi Z, Cuaranta-Monroy I, Nagy L. Nuclear receptors as regulators of stem cell and cancer stem cell metabolism. Seminars in cell & developmental biology. 2013;24(10-12):716-23.

Disclosure of Interests

Lichong Shen: None declared, Yun Zhang: None declared, ZHU Honglin: None declared, Jörg H.W. Distler Shareholder of: stock owner of 4D Science GmbH, Consultant of: JHWD has consultancy relationships and/or has received research funding from AbbVie, Actelion, BMS, Celgene, Bayer Pharma, Boehringer Ingelheim, JB Therapeutics, Sanofi-Aventis, Novartis, UCB, GSK, Array Biopharma and Active Biotech in the area of potential treatments of SSc.

Effect of KRAS codon 12 or 13 mutations on survival with trifluridine/tipiracil in pretreated metastatic colorectal cancer: a meta-analysis

Background

KRAS gene mutations can predict prognosis and treatment response in patients with metastatic colorectal cancer (mCRC).

Methods

We undertook a meta-analysis of three randomized, placebo-controlled trials (RECOURSE, TERRA and J003) to investigate the impact of KRAS mutations in codons 12 or 13 on overall survival (OS) and progression-free survival in patients receiving trifluridine/tipiracil (FTD/TPI) for refractory mCRC.

Results

A total of 1375 patients were included, of whom 478 had a KRAS codon 12 mutation and 130 had a KRAS codon 13 mutation. In univariate analyses, the absence of a KRAS codon 12 mutation was found to significantly increase the OS benefit of FTD/TPI relative to placebo compared with the presence of the mutation {hazard ratio (HR), 0.62 [95% confidence interval (CI): 0.53-0.72] versus 0.86 (0.70-1.05), respectively; interaction P = 0.0206}. Multivariate analyses showed that taking confounding factors into account reduced the difference in treatment effect between the presence and the absence of KRAS codon 12 mutations, confirming that treatment benefit was maintained in patients with [HR, 0.73 (95% CI: 0.59-0.89)] and without [HR, 0.63 (95% CI: 0.54-0.74)] codon 12 mutations (interaction P = 0.2939). KRAS mutations in codon 13 did not reduce the OS benefit of FTD/TPI relative to placebo, and, furthermore, KRAS mutations at either codon 12 or codon 13 did not affect the progression-free survival benefit.

Conclusions

Treatment with FTD/TPI produced a survival benefit, relative to placebo, regardless of KRAS codon 12 or 13 mutation status in patients with previously treated mCRC.

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KRAS mutations are associated with negative outcomes in patients with mCRC; codon 12 and 13 mutations are the most common.

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FTD/TPI was associated with longer median overall survival vs placebo both in patients with wild-type KRAS and mutant KRAS.

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FTD/TPI produced a survival benefit, relative to placebo, regardless of KRAS codon 12 or 13 mutation status in this patient group.

Enhanced charge density wave coherence in a light-quenched, high-temperature superconductor

Superconductivity and charge density waves (CDWs) are competitive, yet coexisting, orders in cuprate superconductors. To understand their microscopic interdependence, a probe capable of discerning their interaction on its natural length and time scale is necessary. We use ultrafast resonant soft x-ray scattering to track the transient evolution of CDW correlations in YBa₂Cu₃O_6+x after the quench of superconductivity by an infrared laser pulse. We observe a nonthermal response of the CDW order characterized by a near doubling of the correlation length within ≈1 picosecond of the superconducting quench. Our results are consistent with a model in which the interaction between superconductivity and CDWs manifests inhomogeneously through disruption of spatial coherence, with superconductivity playing the dominant role in stabilizing CDW topological defects, such as discommensurations.

Optimization of Interface Materials between Bi2Te3-Based Films and Cu Electrodes Enables a High Performance Thin-Film Thermoelectric Cooler

Thermoelectric interface materials (TEiMs) are key to optimizing the electrical contact and stability of the interface between thermoelectric material and metal electrode in high-performance thin-film thermoelectric coolers (TECs). Herein, we explored TEiMs applicable to representative Bi-Te films and found that Cr and Ag are effective TEiMs for p-type Bi_0.5Sb_1.5Te₃ and n-type Bi₂Te₃, respectively. By introducing 200 nm Cr and 200 nm Ag as TEiMs for p-type Bi_0.5Sb_1.5Te₃/Cu and n-type Bi₂Te₃/Cu interfaces, Cu diffusion is suppressed, and excellent electrical contact is achieved (1.81 × 10^-12 Ω m² for p-type and 3.32 × 10^-12 Ω m² for n-type) and remains stable after heat treatment (2.37 × 10^-12 Ω m² for p-type and 1.63 × 10^-12 Ω m² for n-type). Furthermore, the cooling flux of TECs with optimized TEiMs increases from 122.74 to 296.56 W/cm², while the performance degradation caused by contact resistance decreases from 50.81 to 4.15%. In addition, our results show that diffusion occurs between not only Cu but also Ag and the thermoelectric material, as TEiMs diffuse slightly. The diffusion of Cu and Ag at the interface can optimize the electrical contact of Bi₂Te₃/Cu but strongly degrade the electrical contacts of Bi_0.5Sb_1.5Te₃/Cu. Our work provides an optimal selection of TEiMs for high-performance Bi-Te thin film coolers and provides guidance for further miniaturization of devices.