Study on the mechanism of VEGF inducing tolerogenic dendritic cells in oral squamous cell carcinoma / 口腔医学

Objective@#To investigate the mechanism of vascular endothelial growth factor(VEGF) inducing tolerogenic dendritic cells(DCs) in oral squamous cell carcinoma (OSCC).@*Methods@#The DCs were divided into four groups: Control group (DC), VEGF group (VEGF added into DC), Co-culture group (DC co-cultured with SCC7) and Anti-VEGF group (anti-VEGF antibody added into DC co-cultured with SCC7). Flow cytometry (FCM) was used to detect DC surface markers. To detect the effect of DC on proliferation activity of T lymphocyte, the experiment included five groups: Nc group (T lymphocyte), Control group (T lymphocyte added into DC), VEGF group (T lymphocyte + DC + VEGF), Co-culture group (T lymphocyte + DC + supernatant of SCC7) and Anti-VEGF group (T lymphocyte + DC + supernatant of SCC7 + anti-VEGF antibody). Subsequently, the mixed lymphocyte reaction(MLR) was conducted. The expression levels of indole-2, 3-doxygenase(IDO)and programmed cell death 1 ligand 1(PD-L1)in DC were detected by western blot, real time PCR and FCM respectively. For the cytotoxic lymphocyte (CTL) assay, SCC7 cells and CTLs were mixed and CTL-mediated SCC7 cells cytotoxicity was tested. The experiment included four groups: Control group (T lymphocyte + DC), IDO inhibition group (T lymphocyte + DC + IDO inhibitor), Anti-PD-L1 antibody group (T lymphocyte + DC + anti-PD-L1 antibody) and Combination group (T lymphocyte + DC + IDO inhibitor + anti-PD-L1 antibody). The SCC7 tumor-bearing mice treated with IDO inhibitor and the anti-PD-L1 antibody were sacrificed and the tumor inhibition rate and the spleen index were determined. @*Results@#Compared with Control group, exogenous VEGF or SCC7 co-culture inhibited the relative number of DC expressing CD11C, CD80, CD86, CD40 and MHC Ⅱ. The positive DCs were increased in the Anti-VEGF group compared with VEGF or Co-culture group. In VEGF or Co-culture group, the number of T cells stimulated by SCC7-pulsed DCs was decreased compared with Control group. However, the ability of Anti-VEGF group to induce T cell proliferation was significantly increased compared with VEGF or Co-culture group. Significantly increased expression of IDO and PD-L1 were observed in VEGF and Co-culture group. However, this was partially reversed by addition of anti-VEGF antibody into the co-culture system. Compared with Control group, the expressions of CD11C and CD86 in DC in both the IDO inhibition group and Anti-PD-L1 antibody group were increased, and were significantly higher in the Combination group compared with the single drug groups. The similar results were exhibited in MLR and CTL assay. In vivo, the results revealed that the tumors obtained from the mice in three experimental groups were smaller than those in the control group. Furthermore, the tumor volume of the Combination group was the smallest. The spleen index of each group was calculated and the results showed the spleen index of the three experimental groups was significantly higher than that of Control group.@*Conclusion@#VEGF in OSCC micro-environment inhibits the maturation and function of DC that are transformed into tolerogenic DC by high expression of IDO and PD-L1.

Thoracic SMARCA4-deficient undifferentiated tumor-pathological diagnosis and combined immune checkpoint inhibitor treatment / 北京大学学报(医学版)

We explored clinicopathological features and treatment strategies for thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT). Thoracic SMARCA4-UT is a new entity recently acknowledged in the 2021 edition of World Health Organization Classification of Thoracic Tumors, and doctors are relatively unfamiliar with its diagnosis, treatment, and prognosis. Taking a case of SMARCA4-UT treated in Peking University First Hospital as an example, this multi-disciplinary discussion covered several hot issues on diagnosing and treating thoracic SMARCA4-UT, including histological features, immu- nohistochemical and molecular phenotype, immune checkpoint inhibitor (ICI) therapy, and pathological assessment of neoadjuvant therapy response. The patient was an older man with a long history of smoking and was admitted due to a rapidly progressing solid tumor in the lower lobe of the right lung. Histologically, tumor cells were epithelioid, undifferentiated, diffusely positive for CD34, and partially positive for SALL4.The expression of BRG1 protein encoded by SMARCA4 gene was lost in all of tumor cells, and next-generation sequencing(NGS)confirmed SMARCA4 gene mutation (c.2196T>G, p.Y732Ter). The pathological diagnosis reached as thoracic SMARCA4-UT, and the preoperative TNM stage was T1N2M0 (ⅢA). Tumor proportion score (TPS) detected by immunohistochemistry of programmed cell death 1-ligand 1 (PD-L1, clone SP263) was 2%. Tumor mutation burden (TMB) detected by NGS of 1 021 genes was 16. 3/Mb. Microsatellite detection showed the tumor was microsatellite stable (MSS). Neo-adjuvant therapy was implemented with the combined regimen of chemotherapy and ICI. Right lower lobectomy was performed through thoracoscopy after the two weeks' neoadjuvant. The pathologic assessment of lung tumor specimens after neoadjuvant therapy revealed a complete pathological response (CPR). The post-neoadjuvant tumor TNM stage was ypT0N0M0. Then, five cycles of adjuvant therapy were completed. Until October 2022, neither tumor recurrence nor metastasis was detected, and minimal residual disease (MRD) detection was negative. At present, it is believed that if BRG1 immunohistochemical staining is negative, regardless of whether SMARCA4 gene mutation is detected, it should be classified as SMARCA4-deficient tumors. SMARCA4-deficient tumors include a variety of carcinomas and sarcomas. The essential criteria for diagnosing SMARCA4-UT includes loss of BRG1 expression, speci-fic histological morphology, and exclude other common thoracic malignant tumors with SMARCA4-deficiency, such as squamous cell carcinoma, adenocarcinoma and large cell carcinoma. SMARCA4-UT is a very aggressive malignant tumor with a poor prognosis. It has almost no targeted therapy mutations, and little response to chemotherapy, but ICI is currently the only effective drug. The successful diagnosis and treatment for this case of SMARCA4-UT should enlighten significance for various kinds of SMARCA4-deficient tumors.

Consistency comparison of programmed cell death 1-ligand 1 in different immuno-histochemical staining methods / 北京大学学报(医学版)

OBJECTIVE@#To compare the consistency of programmed cell death 1-ligand 1 (PD-L1, clone E1L3N, 22C3, SP263) in different immunohistochemical staining methods.@*METHODS@#The first step was to select the optimal process: The PD-L1(clone E1L3N) antibody recommended process, self-built process ①, self-built process ② and self-built process ③ were used to perform immunohistochemical staining in 5 cases of tonsil tissue. The quality of all slides was scored by expert pathologists (0-6 points). The process with the highest score was selected. The second step was to compare the consistency between the optimal procedure and the two standard procedures. Thirty-two cases of lung non-small cell carcinoma diagnosed by pathology in Peking University First Hospital in the past two years were randomly selected. The 32 cases were stained in parallel with the SP263 and 22C3 standard procedures, and all stained slides were scored by specialized pathologists for tumor proportion score (TPS). The scoring results were grouped according to < 1%, ≥1% to < 10%, ≥10% to < 50%, and ≥50%. The consistency of PD-L1 detection antibody clone E1L3N and 22C3, E1L3N and SP263 staining results was analyzed.@*RESULTS@#Tonsil stained slides scores (0-6 points) were as follows: The recommended protocol was 5, 5, 5, 5 and 5. The self-built process ① was 5, 6, 6, 5 and 6. The self-built process ② was 4, 4, 4, 4 and 4.The self-built process ③ was 3, 3, 3, 3 and 3. The self-built process ① was the best with the highest score. The TPSs of 32 non small cell lung carcinoma (NSCLC) cases were as follows: Of self-built process ①, 6 cases were lower than 1%, 5 cases were from 1% to 10%, 10 cases were from 10% to 50%, and 11 cases were higher than 50%; of 22C3 standard procedure, 5 cases were lower than 1%, 3 cases were from 1% to 10%, 13 cases were from 10% to 50%, 11 cases were higher than 50%; of SP263 standard procedure, 7 cases were lower than 1%, 4 cases were from 1% to 10%, 11 cases were from 10% to 50%, 10 cases were higher than 50%. The results of the consistency test were as follows: The κ value for self-built process ① and 22C3 standard procedure was 0.736 (P < 0.001), the agreement was good; the κ value for self-built process ① and SP263 standard procedure was 0.914 (P < 0.001), the agreement was very good.@*CONCLUSION@#The immunostaining using PD-L1(E1L3N) with validated self-built staining protocol ① by Ventana Benchmark GX platform can obtain high quality of slides, and the TPSs based on these slides are in good agreement with 22C3 and SP263 standard procedures.

Peripheral blood immune cell-based biomarkers in anti-PD-1/PD-L1 therapy

Immune checkpoint blockade targeting PD-1 and PD-L1 has resulted in unprecedented clinical benefit for cancer patients. Anti-PD-1/PD-L1 therapy has become the standard treatment for diverse cancer types as monotherapy or in combination with other anti-cancer therapies, and its indications are expanding. However, many patients do not benefit from anti-PD-1/PD-L1 therapy due to primary and/or acquired resistance, which is a major obstacle to broadening the clinical applicability of anti-PD-1/PD-L1 therapy. In addition, hyperprogressive disease, an acceleration of tumor growth following anti-PD-1/PD-L1 therapy, has been proposed as a new response pattern associated with deleterious prognosis. Anti-PD-1/PD-L1 therapy can also cause a unique pattern of adverse events termed immune-related adverse events, sometimes leading to treatment discontinuation and fatal outcomes. Investigations have been carried out to predict and monitor treatment outcomes using peripheral blood as an alternative to tissue biopsy. This review summarizes recent studies utilizing peripheral blood immune cells to predict various outcomes in cancer patients treated with anti-PD-1/PD-L1 therapy.

The mechanism and research progress of drug resistance of PD-1/PD-L1 immunotherapy in tumors / 药学学报

Programmed cell death protein 1 (PD-1) is an important immunosuppressive molecule, which combines with programmed cell death 1 ligand 1 (PD-L1) to initiate programmed T-cell death, leading to immune escape of tumor cells. Immune checkpoint inhibitors kill tumor cells by blocking the binding of PD-1 to PD-L1 and reactivating the patient's own immune system. With the approval of anti-PD-1 monoclonal antibodies nivolumab, pembrolizumab and anti-PD-L1 monoclonal antibody atezolizumab by FDA for the treatment of melanoma, advanced non-small cell lung cancer and other cancers, cancer treatment has ushered in a new dawn. However, only 20% of patients achieved long-term efficacy after treatment, and most patients relapsed later. Therefore, it is significant to identify effective biomarkers and develop new targets to improve the response of patients to immunotherapy. This article reviews on the mechanism of action of anti-PD-1/PD-L1 drugs in tumors, potential biomarkers and the mechanism of acquired drug resistance, as well as combination therapy under research.

Advances in hyperprogressive disease of PD-1/PD-L1 antibody drugs and rational drug therapy / 药学学报

With the significant breakthrough that programmed cell death 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) antibody drugs achieved promising clinical outcomes across various tumor types, immunotherapy targeting immune checkpoint has been considered a promising way to treat cancer. However, most recently studies suggest that the hyperprogressive disease occurred frequently during the therapy of using PD-1/PD-L1 antibody drugs and has become an urgent problem to be solved. In this review, we summarize the progress and potential reasons of hyperprogressive disease caused by PD-1/PD-L1 blockade, and further discuss its application based on the rational use of biomarkers for searching the benefit patients.

Preparation of fusion protein of PD-L1 single-chain antibody and verification of its antitumor activity / 中国免疫学杂志

Objective: Using yeast surface presentation technology, secreted anti-PD-L1 single-chain antibody fragment ( sc Fv), then purify the sc Fv that specifically binds PD-L1 antigen. The sc Fv antibody gene sequence was synthesized based on the single chain antibody gene sequence. We express this sc Fv-mFc protein by using p Fuse eukaryotic expression vector to study its affinity and in vitro and in vivo inhibition of lung adenocarcinoma cells ( A549). Methods: Recombinant plasmid p Fuse-scFv was constructed by gene engineering. The recombinant plasmid p Fuse-scFv was transfected into 293 F ( human embryonic kidney cells) and cultured in serum-free Pro293 a-CDM for 72 hours, then the fusion protein was collected, and use the Rapid Protein Liquid Phase Separation and Purification System to purify the sc Fv-mFc fusion protein. Then the fusion protein and the tumor cells were detected by immunohistochemistry; the affinity of fusion protein and tumor cells was analyzed by flow cytometry; ADCC was used to determine the proliferation of tumor cells in vitro. The nude mice inoculated with lung adenocarcinoma cells, and use the fusion protein to verify its anti-tumor effect in vivo. Results: sc Fv-mFc fusion protein was secreted into serum-free culture medium by recombinant plasmid transfection into the 293 F cells; immunohistochemistry and flow cytometry showed that the fusion protein was highly expressed with the surface of PD-L1 protein;ADCC showed that the fusion protein inhibited the proliferation of tumor cells in vitro; the results of tumor-bearing mice showed that the fusion protein inhibited the growth of the tumor. At the dose of 5 mg/kg, The tumor volume growth rate decreased from 14. 90％ to3. 72％, the two independent samples t test P＜0. 05, the difference was statistically significant. Conclusion: The fusion protein containing single chain antibody was successfully prepared, which had good binding ability to A549 cells and inhibited the proliferation of tumor cells in vitro and in vivo, and provided the laboratory basis for the development of targeted anti-tumor drugs.

Early Experiences with Nivolumab in Patients with Metastatic Renal Cell Carcinoma and Failed Target Therapy

PURPOSE: The efficacy of nivolumab in metastatic renal cell carcinoma (mRCC) has been proven. However, the nivolumab experience in Korean patients with mRCC is still poorly reported. We report initial experiences with the efficacy and safety of nivolumab in patients with mRCC. MATERIALS AND METHODS: We retrospectively reviewed records for 25 patients with mRCC who had failed targeted therapy and were treated by nivolumab (2 mg/kg, every 2 weeks) at a single institution. The primary endpoint was objective response rate (ORR), and secondary endpoints were progression-free survival (PFS), safety profiles, and ORR in a programmed cell death receptor ligand 1 (PD-L1) expression subgroup. RESULTS: The median age was 60 years and 16 patients (64%) were male. Objective responses were achieved in 8 patients (32.0%) (complete response, 1; partial response, 7). Median PFS was 3.0 months (95% confidence interval, 1.46–4.53). Treatment-related adverse events (AEs) of any grade were observed in 19 patients (76.0%) with 6 (24.0%) experiencing grade 3 to 4 treatment-related AEs. In subgroups by PD-L1 expression levels classified as 1% or greater and less than 1%, ORR was 50% and 0%, respectively. CONCLUSIONS: This study showed the efficacy and safety of initial experiences with nivolumab in Korean patients with mRCC who had failed targeted therapy. Our results were comparable to recent clinical trials on nivolumab in mRCC.