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Primary research
Yi Ba
Tianjin Medical University
Corresponding Author
ORCiD: https://orcid.org/0000-0003-0255-4376
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: The programmed death-1 (PD-1)/PD-ligand 1 (PD-L1) pathway plays crucial role in various types of cancer. However, the underlying mechanism of PD-L1 expression dysregulation in GC has not been revealed. High expression of PD-L1 and low expression of miR-15a/16 often leads to poor prognosis of gastric cancer, therefore PD-L1 was regarded as a key target for the treatment of gastric cancer. This study aims to determine whether exosomes with miR-15a/16 could target PD-L1 and inhibit immune escape in gastric cancer (GC).
Methods: The protein expression levels of PD-L1 in tumor tissues and normal tissues of patients were evaluated by Western blot (WB) and immunohistochemistry (IHC), then confirmed that PD-L1 was a target of miR-15a/16 by luciferase reporter assay. HEK293T cells were transfected with miR-15a/16, exosomes were isolated by sequential differential centrifugation then cultured with gastric cancer cell lines, the protein and RNA levels of the PD-L1 were determined by western blotting and real-time qPCR. A mouse xenograft model was adopted to assess the association between exosome loaded miR-15a/16 and tumor growth in vivo. Flow cytometry was performed to analysis the effect of exo-miR-15a/16 on CD8+T lymphocytes and INFγ+ of mice.
Results: We found that compared to adjacent noncancerous tissues, PD-L1 protein expression was significantly increased while miR-15a/16 expression level was significantly inhibited in tumor tissues. In addition, we found that miR-15a/16 mimics could downregulate PD-L1 expression, while miR-15a/16 inhibitors enhanced PD-L1 expression in human gastric cancer cell line SGC7901. Exo-miR-15a/16 could target PD-L1 and inhibit immune escape in gastric cancer.
Conclusions: Our study confirmed that miR-15a/16 in exosomes could suppress tumor growth and inhibit immune escape by targeting PD-L1 in vivo and in vitro, which might serve as a potential biomarker in monitoring the activity of gastric cancer.
Keywords
Exosomes；PD-L1 ; miR-15a/16; gastric cancer
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This is a preprint. It has not completed peer review.
Primary research
Yi Ba
Tianjin Medical University
Corresponding Author
ORCiD: https://orcid.org/0000-0003-0255-4376
Badges
Prescreen
This manuscript passed our Prescreen assessment
Complete author information
Appropriate declaration statements
Potential risks to human health
Prescreen
History
CURRENT STATUS: Posted
Version 1
Posted 28 May, 2020
No community comments so far
Metrics
Comments: 0
PDF Downloads: ...
HTML Views: ...
License:
This work is licensed under a CC BY 4.0 License. Read Full License
Background: The programmed death-1 (PD-1)/PD-ligand 1 (PD-L1) pathway plays crucial role in various types of cancer. However, the underlying mechanism of PD-L1 expression dysregulation in GC has not been revealed. High expression of PD-L1 and low expression of miR-15a/16 often leads to poor prognosis of gastric cancer, therefore PD-L1 was regarded as a key target for the treatment of gastric cancer. This study aims to determine whether exosomes with miR-15a/16 could target PD-L1 and inhibit immune escape in gastric cancer (GC).
Methods: The protein expression levels of PD-L1 in tumor tissues and normal tissues of patients were evaluated by Western blot (WB) and immunohistochemistry (IHC), then confirmed that PD-L1 was a target of miR-15a/16 by luciferase reporter assay. HEK293T cells were transfected with miR-15a/16, exosomes were isolated by sequential differential centrifugation then cultured with gastric cancer cell lines, the protein and RNA levels of the PD-L1 were determined by western blotting and real-time qPCR. A mouse xenograft model was adopted to assess the association between exosome loaded miR-15a/16 and tumor growth in vivo. Flow cytometry was performed to analysis the effect of exo-miR-15a/16 on CD8+T lymphocytes and INFγ+ of mice.
Results: We found that compared to adjacent noncancerous tissues, PD-L1 protein expression was significantly increased while miR-15a/16 expression level was significantly inhibited in tumor tissues. In addition, we found that miR-15a/16 mimics could downregulate PD-L1 expression, while miR-15a/16 inhibitors enhanced PD-L1 expression in human gastric cancer cell line SGC7901. Exo-miR-15a/16 could target PD-L1 and inhibit immune escape in gastric cancer.
Conclusions: Our study confirmed that miR-15a/16 in exosomes could suppress tumor growth and inhibit immune escape by targeting PD-L1 in vivo and in vitro, which might serve as a potential biomarker in monitoring the activity of gastric cancer.
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
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