BMC Cancer: Is it too difficult to enhance the effect of PD-1 immunotherapy on prostate cancer?

Prostate cancer is one of the most common cancers in the male genitourinary system, and its incidence increases with age
.

The global incidence rate ranks second among male malignant tumors, and its mortality rate ranks fifth among all malignant tumors

Currently PD-1 immunotherapy has been approved as the first-line treatment for prostate cancer patients, but the regulatory mechanism of PD-L1 in prostate cancer is still unclear
.

Therefore, it is of great significance to identify PD-L1 modulators and related clinical biomarkers, predict the patient's response to immunotherapy, and provide new strategies for the treatment of prostate cancer

immunity

This study aims to investigate whether eIF5B affects PD-L1 expression in prostate cancer cells through interaction with Wig1
.

1.
The effect of eIF5B silencing on prostate cancer cells

1.
The effect of eIF5B silencing on prostate cancer cells

The results showed that compared with RWPE-1, the expression of eIF5B and PD-L1 in PC-3 and VCaP cells was significantly increased , so we chose PC-3 and VCaP for follow-up experiments
.

In order to verify the effect of eIF5B on prostate cancer cells, we transfected eIF5B shRNA and its control into PC-3 and VCaP

The results showed that compared with RWPE-1, the expression of eIF5B and PD-L1 in PC-3 and VCaP cells was significantly increased , so we chose PC-3 and VCaP for follow-up experiments

The effect of eIF5B on prostate cancer cells

2.
Silencing eIF5B inhibits the expression of PD-L1 in prostate cancer cells

2.
Silencing eIF5B inhibits the expression of PD-L1 in prostate cancer cells 2.
Silencing eIF5B inhibits the expression of PD-L1 in prostate cancer cells

In order to explore the regulatory relationship between eIF5B and PD-L1 in prostate cancer cells, we used qRT-PCR and Western blot to detect the expression of PD-L1 mRNA and PD-L1 protein in PC-3VCaP cells after interfering with eIF5B expression
.

The results showed that the expression of PD-L1 mRNA and protein in the eIF5B siRNA group were significantly inhibited (P<0.

In order to explore the regulatory relationship between eIF5B and PD-L1 in prostate cancer cells, we used qRT-PCR and Western blot to detect the expression of PD-L1 mRNA and PD-L1 protein in PC-3VCaP cells after interfering with eIF5B expression

Down-regulation of eIF5B can inhibit the expression of PD-L1 in prostate cancer cells

Down-regulation of eIF5B can inhibit the expression of PD-L1 in prostate cancer cells

3.
Silencing eIF5B enhances the ability of PBMC to kill prostate cancer cells

3.
Silencing eIF5B enhances the ability of PBMC to kill prostate cancer cells 3.
Silencing eIF5B enhances the ability of PBMC to kill prostate cancer cells

In order to study the effect of eIF5B on the killing ability of immune cells, we isolated pmcs from normal peripheral blood of healthy people and co-cultured with transfected prostate cancer cells
.

The results showed that in the eIF-5B shRNA group, the number of lymphocytes was significantly higher than that in the no shRNA group or the shRNA and PD-L1 overexpression group (P<0.

In order to study the effect of eIF5B on the killing ability of immune cells, we isolated pmcs from normal peripheral blood of healthy people and co-cultured with transfected prostate cancer cells

Effect of eIF5B on the ability to kill immune cells

4.
The effect of Wig1 overexpression on prostate cancer cells

4.
The effect of Wig1 overexpression on prostate cancer cells 4.
The effect of Wig1 overexpression on prostate cancer cells

The CoIP test to verify the regulatory correlation between Wig1 and eIF5B found that Flag-Wig1 was only detected in the Wig1-Flag group before IP
, and eIF5B was detected in both groups .

After IP, Flag-Wig1 and eIF5B were not detected in the control group, but both were detected in the Wig1-Flag group, indicating that Wig1 can bind to eIF5B

The CoIP test to verify the regulatory correlation between Wig1 and eIF5B found that Flag-Wig1 was only detected in the Wig1-Flag group before IP

The regulation mechanism of Wig1 on eIF5B

The regulation mechanism of Wig1 on eIF5B

5.
Silencing eIF5B inhibits tumor development

5.
Silencing eIF5B inhibits tumor development 5.
Silencing eIF5B inhibits tumor development

In this study, sh-eIF5B lentivirus was constructed and transfected into PC-3 cells to down-regulate the expression level of eIF5B
.
PC-3 cells transfected with sh-eIF5B or sh control were used for tumor transplantation experiments in vivo
.
When the tumor grew to 100 mm3, anti-pd-L1 and IgG antibodies were injected into the mice
.
The mice were sacrificed 30 days after tumor transplantation, and the tumor was taken mobile and photographed, and its volume and weight were recorded
.
The results showed that the sh control group + IgG control group had the largest tumor volume and weight, followed by sh control group + anti-pd-L1 group, sh-eIF5B + IgG control group, sh-eIF5B + anti-pd-L1 group; in addition, differences between groups Significant
.

In this study, sh-eIF5B lentivirus was constructed and transfected into PC-3 cells to down-regulate the expression level of eIF5B
.
PC-3 cells transfected with sh-eIF5B or sh control were used for tumor transplantation experiments in vivo
.
When the tumor grew to 100 mm3, anti-pd-L1 and IgG antibodies were injected into the mice
.
The mice were sacrificed 30 days after tumor transplantation, and the tumor was taken mobile and photographed, and its volume and weight were recorded
.
The results showed that the sh control group + IgG control group had the largest tumor volume and weight, followed by sh control group + anti-pd-L1 group, sh-eIF5B + IgG control group, sh-eIF5B + anti-pd-L1 group; in addition, differences between groups Significant
.

The subsequent HE staining and flow cytometry results showed that the damage of tumor tissue morphology and the content of CD4+ and CD8+ cells in sh- control were the smallest
.
After these two indicators were increased, sh- control + anti-PD-L1 group, sh-eIF5B + IgG control , and sh-eIF5B + anti-PD-L1 group (p<0.
01)
.
These results indicate that PD-L1 antibody or interference with PD-L1 expression can inhibit tumor growth, destroy tumor tissue morphology, increase the content of CD4+ and CD8+ cells, and eIF5B can enhance this beneficial effect
.

-control -control anti-PD-L1 control anti-PD-L1 These results indicate that PD-L1 antibody or interference with PD-L1 expression can inhibit tumor growth, destroy tumor tissue morphology, increase the content of CD4+ and CD8+ cells, and eIF5B can enhance This beneficial effect
.

The results of qRT-PCR, Western blot and immunohistochemistry showed that compared with the sh-control + IgG control group, the expression levels of PD-L1 and eIF-5B in the sh-control + anti-PD-L1 group were not significantly different; however, The expression of sh-eIF5B group was significantly reduced
.

The results of qRT-PCR, Western blot and immunohistochemistry showed that compared with the sh-control + IgG control group, the expression levels of PD-L1 and eIF-5B in the sh-control + anti-PD-L1 group were not significantly different; however, The expression of sh-eIF5B group was significantly reduced
.

The above results suggest that by interfering with the expression of eIF5B instead of PD-L1 antibody, the expression of eIF5B and PD-L1 can be inhibited
.
Moreover, the PD-L1 antibody cannot enhance the changes caused by the interference of eIF5B and PD-L1 expression, and these changes are caused by the interference of eIF5B expression
.

The above results suggest that by interfering with the expression of eIF5B instead of PD-L1 antibody, the expression of eIF5B and PD-L1 can be inhibited
.
Moreover, the PD-L1 antibody cannot enhance the changes caused by the interference of eIF5B and PD-L1 expression, and these changes are caused by the interference of eIF5B expression
.

In summary, this study confirmed that eIF5B can promote the expression of PD-L1 by interacting with Wig1
.
Interfering with the expression of eIF5B can inhibit the proliferation, migration, invasion, immunosuppressive response and tumor growth of prostate cancer cells
.
This indicates that eIF5B may become a new target for prostate cancer immunotherapy
.

In summary, this study confirmed that eIF5B can promote the expression of PD-L1 by interacting with Wig1
.
Interfering with the expression of eIF5B can inhibit the proliferation, migration, invasion, immunosuppressive response and tumor growth of prostate cancer cells
.
This indicates that eIF5B may become a new target for prostate cancer immunotherapy
.
In summary, this study confirmed that eIF5B can promote the expression of PD-L1 by interacting with Wig1
.
Interfering with the expression of eIF5B can inhibit the proliferation, migration, invasion, immunosuppressive response and tumor growth of prostate cancer cells

 

Original source:

Li et al.
eIF5B regulates the expression of PD-L1 in prostate cancer cells by interacting with Wig1.
BMC Cancer (2021) 21:1022
https://doi.
org/10.
1186/s12885-021-08749-w

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