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An effective cytokine adjuvant vaccine induces autologous T-cell response against colon cancer in an animal model

View Article: PubMed Central - PubMed

ABSTRACT

Background: Despite recent advances in early detection and improvements in chemotherapy for colon cancer, the patients still face poor prognosis of postoperative recurrence and metastasis, the median survival for patients with metastatic colorectal cancer is approximately 22–24 months. Some immunotherapeutic approaches had been attempted in colon cancer patients to significantly increase overall survival. A vaccine based approach has shown a novel direction for colon cancer prevention and therapy.

Methods: In this study, the experiments were designed including prevention and therapeutic stages in order to attain effect against tumor recurrence in clinical settings. The anti-tumor efficacy of a novel cytokine adjuvant vaccine that contained cytokines GM-CSF and IL-2 and inactivated colon CT26.WT whole cell antigen was evaluated in BALB/c mouse tumor models by measuring tumor growth post vaccination and the survival time of tumor-bearing mice, analyzing the expression and distribution of CD4, CD8, CD11c, CD80, CD86 and CD83 positive cells in control and treated mice by flow cytometry and immunochemistry. The tumor-specific cytotoxic T cells (CTL) were analyzed by tumor proliferation and the lactic dehydrogenates (LDH) release assays. IFN-γ, IL-2 and GM-CSF secretion in serum was assayed by ELISA.

Results: Our results suggested that cytokine adjuvant vaccine significantly inhibited tumor growth and extended the survival period at least 160d. It was found that the levels of CD8 + T and the tumor-specific cytotoxicity were significantly higher in prevention and treatment group vaccinated by cytokine adjuvant vaccine. CD8 + T cells play a key role in anti-tumor response.

Conclusions: The novel GM-CSF and IL-2 based adjuvant vaccine effectively activated autologous T-cell response and represented a promising immunotherapeutic approach for patients with colon cancer.

Electronic supplementary material: The online version of this article (doi:10.1186/s12865-016-0172-x) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus

Preliminary effect of the cytokine adjuvant vaccine Panel (a), shows the pictures of mice with tumors at day 49 from three different groups. Panel (b), shows the pictures of tumors excised from each group of mice and subsequently these tumors were used to calculate the tumor inhibition rate. Panel (c), represents the comparison of tumor volume (left) and weight (right) between tumor, prevention and treatment group. Panel (d), depicts a survival curve analyzed with a log-rank test of Kaplan-Meier curves using mice from Tumor (control), Prevention and Treatment group, where 20 mice of each group were followed for a period of 160 d (Kaplan Meier, p < 0.001). ***denotes p < 0.001
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Fig2: Preliminary effect of the cytokine adjuvant vaccine Panel (a), shows the pictures of mice with tumors at day 49 from three different groups. Panel (b), shows the pictures of tumors excised from each group of mice and subsequently these tumors were used to calculate the tumor inhibition rate. Panel (c), represents the comparison of tumor volume (left) and weight (right) between tumor, prevention and treatment group. Panel (d), depicts a survival curve analyzed with a log-rank test of Kaplan-Meier curves using mice from Tumor (control), Prevention and Treatment group, where 20 mice of each group were followed for a period of 160 d (Kaplan Meier, p < 0.001). ***denotes p < 0.001

Mentions: Then, we set up the tumor model by subcutaneously injection of CT26.WT colon cancer cells (5 × 105) at day 0. In order to determine if the vaccine had a preventive or therapeutic potential during tumor progression, firstly, we vaccinated the mice in the Prevention group twice, at 10 d (d − 10) and 3 d (d − 3) before tumor cell injection; secondly, in the Treatment group, respective twice vaccinations were given before and after tumor cell injection (d − 10, d − 3, d + 7, d + 14). The data showed that, whereas the weight of mice was not affected by vaccine inoculation (data not shown), the tumor growth as analyzed by tumor volumes and weights, was significantly inhibited in both groups of the vaccinated mice as compared to that in the controls. While 14 out of 14 (100 %) mice in the control group developed heavy tumors, only 6 out of 14 mice (42.8 %) and 2 out of 14 mice (14.3 %) in respective Prevention and Treatment groups had significantly less heavy tumors (Fig. 2a and b). As seen in Fig. 2c, Tumor group mice at 49 d post tumor cell injection had an average tumor volume and weight of 18.17 ± 3.94 cm3 and 10.48 ± 2.65 g respectively, Prevention group mice that were vaccinated two times had an average tumor volume and weight of 9.58 ± 0.36 cm3 and 5.97 ± 0.34 g whereas the Treatment group mice that were vaccinated four times had an average tumor volume 3.48 ± 0.43 cm3 and weight of 2.14 ± 0.21 g (p < 0.01). Furthermore, in comparison to the control group, the tumor inhibition rate was respective 57.1 % and 85.7 % in the Prevention and Treatment group. In addition, the survival rate was also assessed in the Control, Prevention and Treatment groups that each contained 20 mice, until 160 d post tumor cell injection. The data showed that mice in the Treatment group had greatly prolonged survival as compared with the Control group and Prevention group (Fig. 2d, p < 0.001). Taken together, these results indicated that vaccine was vaccinated four times including prevention and therapeutic stages were better than vaccinated two times. Then we discussed the mechanism between Tumor group and Treatment group for repeating experiment.Fig. 2


An effective cytokine adjuvant vaccine induces autologous T-cell response against colon cancer in an animal model
Preliminary effect of the cytokine adjuvant vaccine Panel (a), shows the pictures of mice with tumors at day 49 from three different groups. Panel (b), shows the pictures of tumors excised from each group of mice and subsequently these tumors were used to calculate the tumor inhibition rate. Panel (c), represents the comparison of tumor volume (left) and weight (right) between tumor, prevention and treatment group. Panel (d), depicts a survival curve analyzed with a log-rank test of Kaplan-Meier curves using mice from Tumor (control), Prevention and Treatment group, where 20 mice of each group were followed for a period of 160 d (Kaplan Meier, p < 0.001). ***denotes p < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC5037582&req=5

Fig2: Preliminary effect of the cytokine adjuvant vaccine Panel (a), shows the pictures of mice with tumors at day 49 from three different groups. Panel (b), shows the pictures of tumors excised from each group of mice and subsequently these tumors were used to calculate the tumor inhibition rate. Panel (c), represents the comparison of tumor volume (left) and weight (right) between tumor, prevention and treatment group. Panel (d), depicts a survival curve analyzed with a log-rank test of Kaplan-Meier curves using mice from Tumor (control), Prevention and Treatment group, where 20 mice of each group were followed for a period of 160 d (Kaplan Meier, p < 0.001). ***denotes p < 0.001
Mentions: Then, we set up the tumor model by subcutaneously injection of CT26.WT colon cancer cells (5 × 105) at day 0. In order to determine if the vaccine had a preventive or therapeutic potential during tumor progression, firstly, we vaccinated the mice in the Prevention group twice, at 10 d (d − 10) and 3 d (d − 3) before tumor cell injection; secondly, in the Treatment group, respective twice vaccinations were given before and after tumor cell injection (d − 10, d − 3, d + 7, d + 14). The data showed that, whereas the weight of mice was not affected by vaccine inoculation (data not shown), the tumor growth as analyzed by tumor volumes and weights, was significantly inhibited in both groups of the vaccinated mice as compared to that in the controls. While 14 out of 14 (100 %) mice in the control group developed heavy tumors, only 6 out of 14 mice (42.8 %) and 2 out of 14 mice (14.3 %) in respective Prevention and Treatment groups had significantly less heavy tumors (Fig. 2a and b). As seen in Fig. 2c, Tumor group mice at 49 d post tumor cell injection had an average tumor volume and weight of 18.17 ± 3.94 cm3 and 10.48 ± 2.65 g respectively, Prevention group mice that were vaccinated two times had an average tumor volume and weight of 9.58 ± 0.36 cm3 and 5.97 ± 0.34 g whereas the Treatment group mice that were vaccinated four times had an average tumor volume 3.48 ± 0.43 cm3 and weight of 2.14 ± 0.21 g (p < 0.01). Furthermore, in comparison to the control group, the tumor inhibition rate was respective 57.1 % and 85.7 % in the Prevention and Treatment group. In addition, the survival rate was also assessed in the Control, Prevention and Treatment groups that each contained 20 mice, until 160 d post tumor cell injection. The data showed that mice in the Treatment group had greatly prolonged survival as compared with the Control group and Prevention group (Fig. 2d, p < 0.001). Taken together, these results indicated that vaccine was vaccinated four times including prevention and therapeutic stages were better than vaccinated two times. Then we discussed the mechanism between Tumor group and Treatment group for repeating experiment.Fig. 2

View Article: PubMed Central - PubMed

ABSTRACT

Background: Despite recent advances in early detection and improvements in chemotherapy for colon cancer, the patients still face poor prognosis of postoperative recurrence and metastasis, the median survival for patients with metastatic colorectal cancer is approximately 22&ndash;24 months. Some immunotherapeutic approaches had been attempted in colon cancer patients to significantly increase overall survival. A vaccine based approach has shown a novel direction for colon cancer prevention and therapy.

Methods: In this study, the experiments were designed including prevention and therapeutic stages in order to attain effect against tumor recurrence in clinical settings. The anti-tumor efficacy of a novel cytokine adjuvant vaccine that contained cytokines GM-CSF and IL-2 and inactivated colon CT26.WT whole cell antigen was evaluated in BALB/c mouse tumor models by measuring tumor growth post vaccination and the survival time of tumor-bearing mice, analyzing the expression and distribution of CD4, CD8, CD11c, CD80, CD86 and CD83 positive cells in control and treated mice by flow cytometry and immunochemistry. The tumor-specific cytotoxic T cells (CTL) were analyzed by tumor proliferation and the lactic dehydrogenates (LDH) release assays. IFN-&gamma;, IL-2 and GM-CSF secretion in serum was assayed by ELISA.

Results: Our results suggested that cytokine adjuvant vaccine significantly inhibited tumor growth and extended the survival period at least 160d. It was found that the levels of CD8&thinsp;+&thinsp;T and the tumor-specific cytotoxicity were significantly higher in prevention and treatment group vaccinated by cytokine adjuvant vaccine. CD8&thinsp;+&thinsp;T cells play a key role in anti-tumor response.

Conclusions: The novel GM-CSF and IL-2 based adjuvant vaccine effectively activated autologous T-cell response and represented a promising immunotherapeutic approach for patients with colon cancer.

Electronic supplementary material: The online version of this article (doi:10.1186/s12865-016-0172-x) contains supplementary material, which is available to authorized users.

No MeSH data available.


Related in: MedlinePlus