Lymphopenic condition enhanced the antitumor immunity of PD-1-knockout T cells mediated by CRISPR/Cas9 system in malignant melanoma.

BACKGROUND: Adoptive transfer of PD-1 knockout T cells mediated by CRISPR/Cas9 technology has been used in various cancers and got satisfactory treatment effectiveness. However, the effectiveness was limited due to the low proliferation ability, antigen recognition ability and short lifetime of T cells in vivo. METHOD: In this study, PD-1 knockout T cells mediated by CRISPR/Cas9 system were transferred into lymphopenic mice after sub-lethal dose of total body irradiation. The antitumor effects of PD-1 knockout T cells were comprehensively analyzed by flow cytometry. Moreover, PD-L1 knockout B16 cells were inoculated subcutaneously in lymphopenic mice receiving infusion of naïve T cells to value the role of PD-1/PD-L1 axis on lymphopenia-induced antitumor immunity RESULT: In this study, we found that the PD-1-knockout T cells underwent several rounds of homeostatic proliferation in vivo when they were transferred into lymphopenic mice. The number of IFN-γ-releasing CTL was significantly increased and the tumor growth was remarkably inhibited in lymphopenic mice receiving infusion of PD-1 knockout T cells. The expression of PD-L1 on tumor cells rose smartly in lymphopenic mice undergoing homeostatic proliferation. PD-L1 gene knockout on B16 melanoma cells could effectively enhance the antitumor immunity mediated by the homeostatic proliferation of T cells and significantly inhibited the growth of tumor CONCLUSION: These findings suggested that lymphopenic condition after total body irradiation might be able to create an environment to promote the PD-1 knockout T cells to recognize tumor antigen and undergo homeostatic proliferation, thus induced a more powerful antitumor immunity than adoptively transferring into immunocompetent hosts.

Intravoxel incoherent motion diffusion-weighted imaging for early assessment of combined anti-angiogenic/chemotherapy for colorectal cancer liver metastases.

Background: To explore the value of intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI) in the early assessment of colorectal cancer liver metastases (CRLM). Methods: A total of 34 patients with pathologically confirmed unresectable CRLM were enrolled. All participants uniformly received capecitabine and oxaliplatin (CAPOX) plus bevacizumab chemotherapy as standard first-line treatment for advanced colorectal cancer (CRC). Participants underwent 1.5-T conventional magnetic resonance imaging (MRI) and IVIM-DWI sequence scans with 9 b values (0 to 1,000 s/mm2) before treatment and at 3 weeks of treatment, and conventional MRI scans were performed at 6 and 12 weeks after the initial treatment. The IVIM-DWI parameters in the tumor target area were extracted using image post-processing software, including perfusion fraction (f), true diffusion coefficient (D), and false diffusion coefficient (D*). The response assessment was based on the Response Evaluation Criteria in Solid Tumors (RECIST) v. 1.1 by measuring the longest tumor diameter on dynamic contrast-enhanced (DCE) T1-weighted images. Results: According to the RECIST v. 1.1 criteria, the 34 participants were divided into a response group (n=16) and a non-response group (n=18). In the response group, the f value was significantly lowered (P=0.001) and the D value was significantly increased after treatment (P=0.002). In the non-response group, the D value was increased slightly after treatment (P=0.039), and there was no significant difference in the f value and the D* value. In addition, the f value at baseline was significantly greater in the response group than in the non-response group (0.221±0.033 vs. 0.175±0.040; P=0.001). The receiver operating characteristic (ROC) curve analysis showed that the percentage change of the f value obtained the largest area under the curve (AUC =0.797), and the AUC obtained by the Fisher's linear discriminant analysis (FLDA) method (Δf & ΔD combination) was 0.819. Conclusions: The IVIM-DWI parameters (f values and D values) provided effective assessment of the therapeutic effect of CAPOX combined with bevacizumab in patients with CRLM at an early stage, and the f value of the pre-treatment tumor area was shown to be useful for predicting the treatment response of patients.

[Interleukin-12 over-expression in malignant melanoma B16 cells reduces programmed death-1 expression on T cells in mice with immune reconstitution].

OBJECTIVE: To investigate whether interleukin-12 (IL-12) over-expression in malignant melanoma B16 cells affects the expression level of programmed death-1 (PD-1) on T cells in mice during immune microenvironment reconstruction. METHODS: B16 cells were transfected with an IL-12 expression lentiviral vector, and IL-12 over-expression in the cells was verified qPCR and ELISA. Plate cloning assay was used to compare the cell proliferation activity between B16 cells and B16/IL-12 cells. The expression of IL-12 protein in B16/IL-12 cells-derived tumor tissue were detected by ELISA. C57BL/6 mice were inoculated with B16 cells or B16/IL-12 cells, and 14 days later the proportion of T cells with high expression of PD-1 in the tumor-draining lymph nodes was detected by flow cytometry. Mouse models of immune reconstitution established by 650 cGy X-ray radiation were inoculated with B16 (B16+RT group) or B16/IL-12 (B16/IL-12+RT group) cells, with the mice without X-ray radiation prior to B16 cell inoculation as controls. Tumor growth in the mice was recorded at different time points, and on day 14, flow cytometry was performed to detect the proportion of T cells with high PD-1 expression in the tumor-draining lymph nodes and in the tumor tissue. RESULTS: B16 cells infected with the IL-12-overexpressing lentiviral vector showed significantly increased mRNA and protein levels of IL-12 (P < 0.001) without obvious changes in cell viability (P>0.05). B16/IL-12 cells expressed higher levels of IL-12 than B16 cells in vivo (P < 0.01). In the tumor-bearing mouse models, the proportion of CD4 + PD-1+ T cells was significantly lower in B16/IL-12 group than in B16 group (P < 0.01). In the mice with X-ray radiation-induced immune reconstitution, PD-1 expressions on CD4+ T cells (P < 0.05) and CD8+ T cells (P < 0.01) were significantly higher in B16+ RT group than in the control mice and in B16/IL-12+RT group (P < 0.01 or 0.001); the tumors grew more slowly in B16/IL-12+RT group than in B16 + RT group (P < 0.001). CONCLUSIONS: During immune microenvironment reconstruction, overexpression IL-12 in the tumor microenvironment can reduce the percentage of PD-1 + T cells and suppress the growth of malignant melanoma in mice.

Blocking the PD-1/PD-L1 axis in dendritic cell-stimulated Cytokine-Induced Killer Cells with pembrolizumab enhances their therapeutic effects against hepatocellular carcinoma.

Immune checkpoint therapies for cancer, like the anti-programmed cell death 1 (PD-1) agent pembrolizumab, have gained considerable attention. However, the use of immune checkpoint inhibitors in the context of adoptive immunotherapy is poorly characterized. We investigated the therapeutic efficacy of dendritic cell-stimulated CIK (DC-CIK) cells pretreated with pembrolizumab against hepatocellular carcinoma (HCC) in cytotoxicity assay in vitro and in a nude mouse xenograft model. We used time-lapse imaging to investigate tumor killing. We also performed a survival analysis based on lymphocyte subpopulation-specific mRNA signatures using The Cancer Genome Atlas (TCGA) HCC cohort (n=371 patients). The results indicated that PD-1 inhibition increased the anti-tumor effects of DC-CIK cells over those of DC-CIK cells alone, resulting in a survival benefit importantly. Time-lapse imaging revealed that DC-CIK cells appeared to be more effective and aggressive after anti-PD-1 treatment than after culture in control conditions. The PD-1 inhibitor also induced more effective immune cell infiltration of the tumor. Our analysis of the TCGA HCC cohort confirmed that a genetic signature consistent with a high degree of intratumoral CD8+ T cell infiltration is associated with good prognosis. These results suggest that blockade of the PD-1/PD-L1 axis in DC-CIK cells with a PD-1 inhibitor prior to infusion is a promising therapeutic strategy against HCC.

Synthesis and Activity Evaluation of Nasopharyngeal Carcinoma Inhibitors Based on 6-(Pyrimidin-4-yl)-1H-indazole.

Human nasopharyngeal carcinoma is a common head and neck malignancy with high incidence in Southeast Asia and Southern China. It is necessary to develop safe, effective and inexpensive anticancer agents to improve the therapeutics of patients with nasopharyngeal carcinoma. A series of small molecular compounds based on 6-(pyrimidin-4-yl)-1H-indazole were synthesized and evaluated for antiproliferative activities against human nasopharyngeal carcinoma cell lines SUNE1. Compounds 6b, 6c, 6e and 6l showed potent antiproliferative activities similar to positive control drug cisplatin in vitro with lower nephrotoxicity than it. N-[4-(1H-Indazol-6-yl)pyrimidin-2-yl]benzene-1,3-diamine (6l) was selected for further study. It was found that 6l induced mitochondria-mediated apoptosis and G2 /M phase arrest in SUNE1 cells. Furthermore, compound 6l at 10 mg/kg can suppress the growth of an implanted SUNE1 xenograft with a TGI% (tumor growth inhibition) value of 50 % and did not cause serious side effects in BALB/c nude mice. This study suggests that 6-(pyrimidin-4-yl)-1H-indazole derivatives are a series of small molecule compounds with anti-nasopharyngeal carcinoma activities.

Senescent cells re-engineered to express soluble programmed death receptor-1 for inhibiting programmed death receptor-1/programmed death ligand-1 as a vaccination approach against breast cancer.

Various types of vaccines have been proposed as approaches for prevention or delay of the onset of cancer by boosting the endogenous immune system. We previously developed a senescent-cell-based vaccine, induced by radiation and veliparib, as a preventive and therapeutic tool against triple-negative breast cancer. However, the programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) pathway was found to play an important role in vaccine failure. Hence, we further developed soluble programmed death receptor-1 (sPD1)-expressing senescent cells to overcome PD-L1/PD-1-mediated immune suppression while vaccinating to promote dendritic cell (DC) maturity, thereby amplifying T-cell activation. In the present study, sPD1-expressing senescent cells showed a particularly active status characterized by growth arrest and modified immunostimulatory cytokine secretion in vitro. As expected, sPD1-expressing senescent tumor cell vaccine (STCV/sPD-1) treatment attracted more mature DC and fewer exhausted-PD1+ T cells in vivo. During the course of the vaccine studies, we observed greater safety and efficacy for STCV/sPD-1 than for control treatments. STCV/sPD-1 pre-injections provided complete protection from 4T1 tumor challenge in mice. Additionally, the in vivo therapeutic study of mice with s.c. 4T1 tumor showed that STCV/sPD-1 vaccination delayed tumorigenesis and suppressed tumor progression at early stages. These results showed that STCV/sPD-1 effectively induced a strong antitumor immune response against cancer and suggested that it might be a potential strategy for TNBC prevention.

MCM6 promotes metastasis of hepatocellular carcinoma via MEK/ERK pathway and serves as a novel serum biomarker for early recurrence.

BACKGROUND: The high incidence of recurrence and metastasis of hepatocellular carcinoma (HCC) necessitate the discovery of new predictive biomarkers of invasion and prognosis. Minichromosome maintenance complex component 6 (MCM6), which has been reported to up-regulate in multiple malignancies, was considered to be a novel diagnoses biomarker in HCC. However, its functional contributions and prognostic value remain unclear. METHODS: The expression of MCM6 was analyzed in 70 HCC tissues and 5 HCC cell lines by immunohistochemistry and real-time RT-PCR. The roles of MCM6 in HCC cell proliferation, migration and invasion were explored by CCK8, Wound healing and Transwell assays, respectively. Western blotting and Immunofluorescence staining were conducted to detect the protein expressions of ERK signaling pathway and EMT-related markers. To verify the above findings in vivo, we established subcutaneous xenograft tumor and orthotopic xenograft tumor models in nude mice. Finally, Enzyme-linked immunosorbent assay was used to evaluate the serum MCM6 level. RESULTS: MCM6 was significantly up-regulated in HCC tissues. Increased MCM6 expression was associated with aggressive clinicopathological features and worse prognosis in HCC patients. These results were consistent with our analyses of The Cancer Genome Atlas database (TCGA). Furthermore, knockdown of MCM6 significantly decreased proliferative and migratory/invasive capability of HCC cells in vitro, as well as decreased tumor volume, weight and the number of pulmonary metastases in vivo. Mechanistic analyses indicated that MCM6 promoted EMT and activated MEK/ERK signaling. More importantly, serum MCM6 levels in HCC patients were significantly higher than those in cirrhosis and healthy controls (P < 0.0001), and allowed distinguishing early recurrence with high accuracy (AUC = 0.773). CONCLUSIONS: Our findings indicate that MCM6 predicts poor prognosis and promotes metastasis in HCC. Postoperative serum MCM6 level could be valuable to detect preclinical early recurrence, indicative of a need for more careful surveillance and aggressive therapeutic intervention.

Notch1 signaling in melanoma cells promoted tumor-induced immunosuppression via upregulation of TGF-ß1.

BACKGROUND: The receptors of Notch family play an important role in controlling the development, differentiation, and function of multiple cell types. The aim of this study is to investigate the role of Notch1 signaling upon immune suppression induced by melanoma cells. METHODS: Melanoma cell line B16 cells were transfected by lentivirus containing mouse Notch1 gene or Notch1 shRNA to generate B16 cell line that highly or lowly expressed Notch1. Notch1 in anti-tumor immune response was comprehensively appraised in murine B16 melanoma tumor model in immunocompetent and immunodeficient mice. The ratios of CD3+CD8+ cytotoxic T cells, CD49b+NK cells, CD4+CD25+FoxP3+ Tregs and Gr1+CD11b+ MDSCs in tumor-DLN or spleen were examined by flow cytometry. After the co-culture of B16 cells and CD8+ T cells, the effects of Notch1 on the proliferation and activation of T cells were assessed by CCK8 assay, CFSE dilution and Chromium-release test. The mRNA expression and supernatant secretion of immunosuppressive cytokines, TGF-ß1, VEGF, IL-10 and IFN-γ were measured by RT-PCR and ELISA, respectively. RESULTS: Downregulation or overexpression of Notch1 in B16 melanoma cells inhibited or promoted tumor growth in immunocompetent mice, respectively. Notch1 expression in B16 melanoma cells inhibited the infiltration of CD8+ cytotoxic T lymphocytes and NK cells and reduced IFN-γ release in tumor tissue. It could also enhance B16 cell-mediated inhibition of T cell proliferation and activation, and upregulate PD-1 expression on CD4+ and CD8+ T cells. The percentage of CD4+CD25+FoxP3+ Tregs and Gr1+CD11b+MDSCs were significantly increased in tumor microenvironment, and all these were attributed to the upregulation of TGF-ß1. CONCLUSION: These findings suggested that Notch1 signaling in B16 melanoma cells might inhibit antitumor immunity by upregulation of TGF-ß1.

[Soluble PD-1 over-expression enhances the anti-tumor effect of senescence tumor cell vaccine against breast cancer cell growth in tumor-bearing mice].

OBJECTIVE: To investigate whether soluble PD-1 overexpression in 4T1 senescence tumor cells enhances the antitumor effect of senescence tumor cell vaccine (STCV) against breast tumor cells in a tumor-bearing mouse model. METHODS: 4T1 cells were treated with interferon-γ (IFN-γ) and the expression of PD-L1 was detected by flow cytometry. CCK8 assay was used to compare the cell proliferation activity between 4T1 cells and 4T1 cells infected by a lentiviral vector of sPD-1 (4T1/sPD-1 cells), and the expressions of sPD-1 mRNA and protein in 4T1/sPD-1 cells were detected using qPCR and Western blotting. The culture supernatant of 4T1/sPD-1 cells was added in 4T1 cells pre-treated with IFN-γ, and PD-1-positive 4T1 cells were detected with flow cytometry. Senescence ß-galactosidase staining kit was used to detect the senescent 4T1 and 4T1/sPD-1 cells following exposure to X-ray radiation and Veliparib. Balb/c mice bearing subcutaneous 4T1 tumor xenografts were treated with injections of PBS, 4T1 STCV, or 4T1/sPD-1 STCV, and tumor growth was observed. RESULTS: Stimulation with IFN-γ concentration-dependently up-regulated PD-L1 expression by as much as (84.80 ± 1.03)% in 4T1 cells (P < 0.001). sPD-1 overexpression in 4T1 cells did not significantly affect the cell proliferation. Treatment of 4T1 cells with 4T1/sPD-1 cell culture supernatant significantly increased the proportion of PD-1 + cells from (6.893 ± 0.271)% to (55.450 ± 0.555)% (P < 0.001). X-ray irradiation combined with Veliparib caused obvious senescence in 4T1 and 4T1/sPD-1 cells. In the tumor-preventing experiment, tumor formation occurred in all the mice in PBS group; 28.787% of the mice in 4T1 STCV group and 55.556% in 4T1/sPD-1 STCV group showed no tumor formation. In the tumor treatment experiment, tumor formation occurred in all the mice in PBS groups while in 4T1 STCV and 4T1/sPD-1 STCV groups, 11.111% and 38.89% of the mice were tumor-free during the observation period, respectively. CONCLUSIONS: Senescence tumor cells vaccine has antitumor effect against breast cancer in mice, and sPD-1 overexpression can enhance this effect of the vaccine.

[C-reactive protein/albumin ratio as a novel inflammation-based prognostic index for predicting outcomes of patients with colorectal cancer].

OBJECTIVE: To evaluate the association of C-reactive protein/albumin ratio (CAR) with the prognosis of patients with colorectal cancer and compare the prognostic value of CAR with other inflammation-based prognostic scoring systems. METHODS: We retrospectively evaluated 163 newly diagnosed colorectal cancer patients in Nanfang Hospital between January, 2007 and December, 2014. All recommended cutoff values of the clinicopathological factors were defined using receiver- operating characteristic (ROC) curve analyses. We evaluated the prognostic value of CAR in comparison with Glasgow Prognostic Score (GPS) and neutrophil lymphocyte ratio (NLR) with the area under the ROC curve. Univariate and multivariate analyses using the Cox proportional hazards model were performed to identify the factors closely associated with overall survival of the patients. Kaplan-Meier analysis was used to compare overall survival curves between patients with a high CAR and those with a low CAR. RESULTS: The recommended cutoff value of CAR was 0.132. Kaplan-Meier analysis and log rank test demonstrated a significant difference in the overall survival between patients with a low CAR (<0.132) and those with a high CAR (≥0.132) (2157.0∓395.3 vs 1661.0∓136.4 days, P<0.001). The area under the ROC curve of CAR, NLR and GPS was 0.656, 0.550 and 0.642, respectively, indicating a better prognostic value of CAR. Univariate analyses showed that age, C-reactive protein, albumin, CAR, NLR, GPS, platelet, TMN stage, Dukes stage and chemotherapy regimens were associated with the overall survival of the patients (P<0.05). Multivariate analyses showed that TMN stage [HR=1.689 (95%CI: 1.146-2.488), P=0.008] and Dukes stage [HR=2.447 (95%CI: 1.349-4.441), P=0.003] were associated with the overall survival of the patients. CONCLUSIONS: Similar to the previously reported inflammation-based prognostic systems (GPS and NLR), CAR is useful for predicting the survival of patients with colorectal cancer and can be complementary to the two prognostic scoring systems.

The pretreatment albumin to globulin ratio, a validated biomarker, predicts prognosis in hepatocellular carcinoma.

PURPOSE: Although the albumin to globulin ratio (AGR) has been proven to be a prognostic factor in several cancers, no studies have assessed its prognostic significance in hepatocellular carcinoma (HCC). Therefore, this study aimed to investigate the prognostic value of the pretreatment AGR in the survival in HCC patients. METHODS: 150 patients were enrolled, who were confirmed of HCC from October 2008 to December 2012 in Nanfang Hospital of Southern Medical University. Demographic, clinical and laboratory data were obtained. Univariate and multivariate Cox regression analysis were used to investigate the association of clinicopathological parameters with HCC patients' survival. RESULTS: Patients were divided into 2 groups: AGR?1.18 and AGR ?1.18. Patients in the high AGR (?1.18) group had longer overall survival (OS) than those in the low AGR (<1.18) group (60.16 vs 20.48 months, p<0.001). Univariate analysis showed that portal vein tumor thrombosis, grade of differentiation, extrahepatic metastasis, BCLC stage, AFP level and AGR at diagnosis were significantly associated with OS. Multivariate analysis revealed that AGR (p<0.001) and grade of differentiation (p=0.007) were independent prognostic factors for survival of HCC patients. In subgroup analysis based on age and Child-Pugh class, AGR remained a significant prognostic parameter. CONCLUSION: Low pretreatment AGR was significantly associated with shorter OS in HCC patients. The pretreatment AGR could be a useful and effective prognostic index for identifying patients with poor prognosis, even when patients have well-preserved liver reserve function.

Small interfering RNA (siRNA)-mediated knockdown of Notch1 suppresses tumor growth and enhances the effect of IL-2 immunotherapy in malignant melanoma.

PURPOSE: Malignant melanoma (MM) is a highly aggressive neoplasm that is resistant to conventional therapies. In this study, we aimed to investigate the effects of antitumor and immune enhancement of Notch1 knockdown on MM. METHODS: Mouse melanoma cells B16F1 were transfected with a small interfering RNA (siRNA) targeting Notch1 (siNotch1). RESULTS: The expression of Notch1 and its downstream hey1 was significantly decreased, resulting in reduced cell proliferation in vitro. Furthermore, intratumoral injection of siNotch1 successfully inhibited the expression of Notch1 and hey1, which suppressed tumor growth, and increased the number of tumor-infiltrating CD8+ T lymphocytes and IFN-γ secretion in vivo, especially when combined with IL-2 immunotherapy. CONCLUSION: These results suggested that siRNA-mediated Notch1 knockdown might be an effective method for the inhibition of tumor growth both in vivo and in vitro, and might potentially enhance the effect of IL-2 immunotherapy in MM. Notch1 knockdown concurrently administered with IL-2 might be a novel therapeutic approach for the treatment of MM.