Key mechanistic features of the trade-off between antibody escape and host cell binding in the SARS-CoV-2 Omicron variant spike proteins.

Since SARS-CoV-2 Omicron variant emerged, it is constantly evolving into multiple sub-variants, including BF.7, BQ.1, BQ.1.1, XBB, XBB.1.5 and the recently emerged BA.2.86 and JN.1. Receptor binding and immune evasion are recognized as two major drivers for evolution of the receptor binding domain (RBD) of the SARS-CoV-2 spike (S) protein. However, the underlying mechanism of interplay between two factors remains incompletely understood. Herein, we determined the structures of human ACE2 complexed with BF.7, BQ.1, BQ.1.1, XBB and XBB.1.5 RBDs. Based on the ACE2/RBD structures of these sub-variants and a comparison with the known complex structures, we found that R346T substitution in the RBD enhanced ACE2 binding upon an interaction with the residue R493, but not Q493, via a mechanism involving long-range conformation changes. Furthermore, we found that R493Q and F486V exert a balanced impact, through which immune evasion capability was somewhat compromised to achieve an optimal receptor binding. We propose a "two-steps-forward and one-step-backward" model to describe such a compromise between receptor binding affinity and immune evasion during RBD evolution of Omicron sub-variants.

KRAS G12V neoantigen specific T cell receptor for adoptive T cell therapy against tumors.

KRAS mutations are broadly recognized as promising targets for tumor therapy. T cell receptors (TCRs) can specifically recognize KRAS mutant neoantigens presented by human lymphocyte antigen (HLA) and mediate T cell responses to eliminate tumor cells. In the present study, we identify two TCRs specific for the 9-mer KRAS-G12V mutant neoantigen in the context of HLA-A*11:01. The TCR-T cells are constructed and display cytokine secretion and cytotoxicity upon co-culturing with varied tumor cells expressing the KRAS-G12V mutation. Moreover, 1-2C TCR-T cells show anti-tumor activity in preclinical models in female mice. The 9-mer KRAS-G12V mutant peptide exhibits a distinct conformation from the 9-mer wildtype peptide and its 10-mer counterparts. Specific recognition of the G12V mutant by TCR depends both on distinct conformation from wildtype peptide and on direct interaction with residues from TCRs. Our study reveals the mechanisms of presentation and TCR recognition of KRAS-G12V mutant peptide and describes TCRs with therapeutic potency for tumor immunotherapy.

Heparin-Binding Protein Aggravates Acute Lung Injury in Septic Rats by Promoting Macrophage M1 Polarization and NF-κB Signaling Pathway Activation.

Objective: Heparin-binding protein (HBP) plays an important role in sepsis and is a prognostic biomarker in patients with sepsis, but the role of HBP in the pathogenesis of sepsis-associated acute lung injury (ALI) remains unclear. This study aimed to investigate the role of HBP in sepsis-induced ALI and its underlying molecular mechanisms. Methods: The cecal ligation and puncture (CLP) model was used to induce ALI in mice and randomly divided into 4 groups: control group, CLP (rats treated with cecal ligation and puncture), HBP (rats treated with CLP and HBP injection), and HBP + UFH (rats treated with CLP and injection of HBP and unfractionated heparin). Subsequently, HBP expression in rat serum and lung tissues was detected by qRT-PCR, edema and pathological changes in lung tissue by lung wet-to-dry weight ratio (W/D) and HE staining, myeloperoxidase (MPO) and superoxide dismutase (SOD) activities in lung tissues by detection kits. Additionally, ELISA and western blot were applied for the determination of IL-6, TNF-α, and IL-1ß expression in rat bronchoalveolar lavage fluid, and iNOS, Arg-1, Mrc1, NF-κBp65, IKKα, IκBα, and p-IκBα expression in lung tissues. Results: The expression levels of HBP in serum and lung tissues of rats in the HBP group were significantly increased, the lung tissues were severely injured, accompanied by a significant increase in MPO activity but a significant decrease in SOD activity, and the levels of IL-6, TNF-α, and IL-1ß in bronchoalveolar lavage fluid were significantly increased. In addition, the expression levels of iNOS, NF-κB p65, IKKα, and p-IκBα in the lung tissues of rats in the HBP group were significantly increased, while the addition of unfractionated heparin reversed the above results. Conclusion: HBP aggravates ALI in septic rats, and its mechanism may be related to the promotion of macrophage M1 polarization and activation of the NF-κB signaling pathway.

Microwave ablation plus chemotherapy versus chemotherapy in advanced non-small cell lung cancer: a multicenter, randomized, controlled, phase III clinical trial.

OBJECTIVES: This prospective trial was performed to verify whether microwave ablation (MWA) in combination with chemotherapy could provide superior survival benefit compared with chemotherapy alone. MATERIALS AND METHODS: From March 1, 2015, to June 20, 2017, treatment-naïve patients with pathologically verified advanced or recurrent non-small cell lung cancer (NSCLC) were randomly assigned to MWA plus chemotherapy group or chemotherapy group. The primary endpoint was progression-free survival (PFS), while the secondary endpoints included overall survival (OS), time to local progression (TTLP), and objective response rate (ORR). The complications and adverse events were also reported. RESULTS: A total of 293 patients were randomly assigned into the two groups. One hundred forty-eight patients with 117 stage IV tumors were included in the MWA plus chemotherapy group. One hundred forty-five patients with 113 stage IV tumors were included in the chemotherapy group. The median follow-up period was 13.1 months and 12.4 months, respectively. Median PFS was 10.3 months (95% CI 8.0-13.0) in the MWA plus chemotherapy group and 4.9 months (95% CI 4.2-5.7) in the chemotherapy group (HR = 0.44, 95% CI 0.28-0.53; p < 0.0001). Median OS was not reached in the MWA plus chemotherapy group and 12.6 months (95% CI 10.6-14.6) in the chemotherapy group (HR = 0.38, 95% CI 0.27-0.53; p < 0.0001) using Kaplan-Meier analyses with log-rank test. The median TTLP was 24.5 months, and the ORR was 32% in both groups. The adverse event rate was not significantly different in the two groups. CONCLUSIONS: In patients with advanced NSCLC, longer PFS and OS can be achieved with the treatment of combined MWA and chemotherapy than chemotherapy alone. KEY POINTS: • Patients treated with MWA plus chemotherapy had superior PFS and OS over those treated with chemotherapy alone. • The ORR of patients treated with MWA plus chemotherapy was similar to that of those treated with chemotherapy alone. • Complications associated with MWA were common but tolerable and manageable.

Immune abscopal effect of microwave ablation for lung metastases of endometrial carcinoma.

Increasing evidence support that microwave ablation (MWA) induces spontaneous abscopal regression of the tumor, also called as the abscopal effect. Although the abscopal effect after MWA is a rare event, several studies have suggested that this effect is the result of the activation of the immune system induced by the death of immunogenic tumor cells. Here, we have presented the case of a 65-year-old woman with primary endometrial cancer who developed bilateral pulmonary metastases. After local MWA of one lesion in her right lung, progressive regression of the other lesions in the right and left lungs was recorded. This case supports the hypothesis that the abscopal effect is attributable to the activation of the systemic immune response.

EphB3-targeted regulation of miR-149 in the migration and invasion of human colonic carcinoma HCT116 and SW620 cells.

microRNAs play key roles during various crucial cell processes such as proliferation, migration, invasion and apoptosis. Also, microRNAs have been shown to possess oncogenic and tumor-suppressive functions in human cancers. Here, we describe the regulation and function of miR-149 in colorectal cancer cell lines. miR-149 expression patterns were detected in human colorectal cell lines and tissue samples, and then focused on its role in regulation of cell growth, migration, invasion, and its target gene identification. Furthermore, the function of the target gene of miR-149 was analyzed in vitro and in vivo. miR-149 expression was downregulated in human colorectal cancer HCT116 and SW620 cell lines compared to the normal colon epithelial NCM460 cell line using quantitative real-time polymerase chain reaction methods. Further studies indicated that introduction of miR-149 was able to suppress cell migration and invasion. Then, EphB3 was identified as a direct target gene of miR-149 in colorectal cancer cells. Moreover, experiments in vitro showed that knockdown expression of EphB3 could suppress cell proliferation and invasion, and ectopic expression of EphB3 restored the phenotypes of CRC cell lines transfected with miR149. In addition, silencing of EphB3 significantly affected cycle progression distribution and increased apoptosis in CRC cell lines. Finally, in vivo results demonstrated that knockdown of EphB3 by siRNA inhibited tumor growth. In conclusion,the important role of miR-149 in colorectal cancer progression suggesting that miR-149 may serve as a therapeutic target for colorectal cancer treatment.

The development of dual-label time-resolved fluorescence immunoassay (TRFIA) for screening of ovarian cancer based on simultaneous detection of human epididymis protein-4 and cancer antigen 125.

A two-step dual-label TRFIA was developed for the simultaneous detection of human epididymis protein-4 and cancer antigen 125 in a single run. The performance of this assay was first evaluated using clinical serum samples, and then compared with commercialized kits. The sensitivity of this assay for cancer antigen 125 detection was 0.5 U/mL (dynamic range, 0-1400 U/L), and the sensitivity for human epididymis protein-4 detection was 1 pM (dynamic range, 1-900 pM). High correlation coefficients (R) were obtained between the present dual-label TRFIA and commercially available kits (R = 0.99). The present dual-label TRFIA has high sensitivity, specificity, and accuracy in clinical sample analysis. It is a good alternative to the single-label diagnostic methods.