Cetuximab enhances radiosensitivity of esophageal squamous cell carcinoma cells by G2/M cycle arrest and DNA repair delay through inhibiting p-EGFR and p-ERK.

BACKGROUND: Although radiotherapy has improved local control in esophageal squamous cell carcinoma (ESCC), a considerable number of patients still experience relapse due to resistance. In this study, we aimed to evaluate the effects of cetuximab on radiosensitivity in two ESCC cell lines (ECA109 and TE-13) and to investigate their underlying mechanisms. METHODS: Cells were pretreated with or without cetuximab before irradiation. The MTT assay and clonogenic survival assay were performed to evaluate cell viability and radiosensitivity. Flow cytometry was performed to analyze cell cycle distribution and apoptosis. The γH2AX foci were counted to determine cellular DNA-repairing capacity via immunofluorescence assay. The phosphorylation of key molecules involved in the epidermal growth factor receptor (EGFR) signaling pathway and DNA double-strand break (DSB) repair were measured by western blot. RESULTS: Cetuximab alone was not sufficient to suppress cell viability, but significantly enhanced radiation-induced inhibition of clonogenic survival in ECA109 and TE-13. The radiation sensitivity enhancement ratio (SER) was 1.341 and 1.237 for ECA109 and TE-13, respectively. ESCC cells treated with cetuximab were arrested at the G2/M phase in response to radiation. No significant increase in apoptotic rate was observed in irradiated cells that were treated with cetuximab. The average number of γH2AX foci increased in the combination group (cetuximab and radiation). Cetuximab suppressed phosphorylation of EGFR and downstream ERK, but had no significant effect on AKT. CONCLUSIONS: These results indicate the potential for use of cetuximab as an effective radiosensitizer in ESCC. Cetuximab promotes G2/M cycle arrest and reduces DSB repair, as well as inhibiting EGFR and downstream ERK pathways in ESCC.

Sustained release of tumor cell lysate and CpG from an injectable, cytotoxic hydrogel for melanoma immunotherapy.

Many basic research studies have shown the potential of autologous cancer vaccines in the treatment of melanoma. However, some clinical trials showed that simplex whole tumor cell vaccines can only elicit weak CD8+ T cell-mediated antitumor responses which were not enough for effective tumor elimination. So efficient cancer vaccine delivery strategies with improved immunogenicity are needed. Herein, we described a novel hybrid vaccine "MCL" (Melittin-RADA32-CpG-Lysate) which was composed of melittin, RADA32, CpG and tumor lysate. In this hybrid vaccine, antitumor peptide melittin and self-assembling fusion peptide RADA32 were assembled to form the hydrogel framework melittin-RADA32(MR). Then, whole tumor cell lysate and immune adjuvant CpG-ODN were loaded into MR to develop an injectable and cytotoxic hydrogel MCL. MCL showed excellent ability for sustained drug release, to activate dendritic cells and directly kill melanoma cells in vitro. In vivo, MCL not only exerted direct antitumor activity, but also had robust immune initiation effects including the activation of dendritic cells in draining lymph nodes and the infiltration of cytotoxic T lymphocytes (CTLs) in tumor microenvironment. In addition, MCL can efficiently inhibit melanoma growth in B16-F10 tumor bearing mice, which suggested that MCL is a potential cancer vaccine strategy for melanoma treatment.

Development and validation of an online prognostic nomogram for osteosarcoma after surgery: a retrospective study based on the SEER database and external validation with single-center data.

Background: Osteosarcoma is a severe malignancy with relatively low morbidity and significant variation in patient outcomes. Thus the development of predictive models could help clinicians make better-individualized decisions. The present study established a nomogram to predict postoperative survival of osteosarcoma patients using the large population-based Surveillance, Epidemiology, and End Results (SEER) database and validated it with single-center data from an Asian/Chinese population. Methods: Data from osteosarcoma patients who underwent surgery from 2000 to 2016 in the SEER database were obtained and were randomly divided into a training set (n=1,057) and an internal validation set (n=1,057). Data from osteosarcoma patients who underwent surgery in our hospital from 2013 to 2016 were collected as an external validation set (n=65). Univariate and multivariate Cox proportional hazard models were used in the training set to screen for prognostic factors and a nomogram was established to individually predict 1-, 3- and 5-year cancer-specific survival (CSS) and overall survival (OS). The discrimination and calibration ability of the nomogram were evaluated using the Harrell concordance index (C-index), calibration curves and area under the curve (AUC). The clinical utility was evaluated using decision curve analysis (DCA). Results: Predictive nomograms were generated using characteristics including age, pathological subtype, the American Joint Committee on Cancer (AJCC) group-N, AJCC-M, tumor size, and tumor extension for CSS and OS. The C-indexes for the CSS training set, the internal validation set, and the external validation set were 0.731, 0.713, and 0.721, respectively. The C-indexes of OS C-indices were 0.734, 0.706, and 0.719, respectively. The calibration curve suggested that the nomograms were accurate in their predictions and that DCA showed broad clinical benefits. Moreover, the present nomograms exhibited high accuracy (for CSS: AUC =0.871, 0.772, and 0.759 of 1-, 3-, and 5-year; for OS: AUC =0.869, 0.774, and 0.765 of 1-, 3-, and 5-year) versus AJCC-Stage (for CSS: AUC =0.744, 0.670, and 0.671 of 1-, 3-, and 5-year; for OS: AUC =0.721, 0.665, and 0.662 of 1-, 3-, and 5-year). Conclusions: This study developed and validated a prognostic nomogram integrating clinicopathological characteristics for osteosarcoma patients who underwent surgery. This nomogram can provide individual risk assessment for survival.

Secretions from hypochlorous acid-treated tumor cells delivered in a melittin hydrogel potentiate cancer immunotherapy.

Autologous tumor cells and cell-derived secretions (CDS) can induce antitumor immune responses. The conditions in which cells are cultured and treated impact CDS, and cellular insults alter their composition and function. In this study, we generated CDS from tumor cells exposed to normal culture conditions, hypoxia, cisplatin, radiotherapy, photodynamic therapy, or hypochlorous acid (HOCl). In vitro HOCl-CDS showed the strongest stimulatory effects on dendritic cells and macrophages compared to CDS generated by hypoxia, cisplatin, radiotherapy or photodynamic therapy. To improve HOCl-CDS activity at the tumor site, we loaded HOCl-CDS into a melittin-encapsulated hydrogel scaffold. When injected intratumorally, the HOCl-CDS hydrogel promoted tumor cell death, cytotoxic T lymphocyte infiltration, and tumor-associated macrophage reprogramming towards an M1 phenotype. The hydrogel inhibited tumor growth and prolonged the survival of mice bearing B16-F10 melanoma. Furthermore, hydrogel-delivered HOCl-CDS augmented the antitumor effects of immune checkpoint blockade. These results underscore the importance of the CDS generation method and delivery approach for improving cancer immunotherapy.

The Predictive Value of MAP2K1/2 Mutations on Efficiency of Immunotherapy in Melanoma.

Background: MAP2K1/2 genes are mutated in approximately 8% of melanoma patients; however, the impact of MAP2K1/2 gene alterations on the efficiency of immunotherapy has not been clarified. This study focused on the correlation between MAP2K1/2 gene mutations and the treatment response. Methods: Six metastatic melanoma clinical cohorts treated with immune checkpoint inhibitors [anti-cytotoxic T lymphocyte antigen-4 (CTLA-4) or anti-programmed cell death-1 (PD-1)] were recruited in this study. RNA expression profiling results from each of these six cohorts and the Cancer Genome Atlas (TCGA) melanoma cohort were analysed to explore the mechanism related to immune activation. Results: Compared to patients with wild-type MAP2K1/2, those with MAP2K1/2 mutations in an independent anti-CTLA-4-treated cohort had higher objective response rates, longer progression-free survival, and longer overall survival (OS). These findings were further validated in a pooled anti-CTLA-4-treated cohort in terms of the OS. However, there was no correlation between MAP2K1/2 mutations and OS in the anti-PD-1-treated cohort. Subgroup Cox regression analysis suggested that patients with MAP2K1/2 mutations received fewer benefits from anti-PD-1 monotherapy than from anti-CTLA-4 treatment. Furthermore, transcriptome profiling analysis revealed that melanoma tumours with MAP2K mutation was enriched in CD8+ T cells, B cells, and neutrophil cells, also expressed high levels of CD33 and IL10, implying a potential mechanism underlying the benefit of melanoma patients with MAP2K1/2 mutations from anti-CTLA-4 treatment. Conclusions: MAP2K1/2 mutations were identified as an independent predictive factor for anti-CTLA-4 therapy in melanoma patients. Anti-CTLA-4 treatment might be more effective than anti-PD-1 therapy for patients with MAP2K1/2-mutated melanoma.