Application of scavenger receptor SR-B1 in treatment of colorectal cancer

Abstract

The invention discloses an application of a scavenger receptor SR-B1 in treatment of colorectal cancer. The research of the inventor finds that SR-B1 is highly expressed in colorectal cancer tissues, and SR-B1 gene knockout inhibits development of colorectal cancer, improves the lifetime, regulates intestinal flora of a colorectal cancer model mouse and enhances anti-colorectal cancer immune response. The SR-B1 gene knockout is combined with anti-PD1 for treatment, so that the development of the colorectal cancer is remarkably inhibited, the intestinal mechanical barrier is improved, and the SR-B1 can be used as a new target for treating the colorectal cancer. A novel medicine for treating the colorectal cancer and a reagent for early diagnosis and detection of the colorectal cancer can be developed according to the target spot.

Description

Technical Field

[0001] The present invention relates to the application of scavenger receptor SR-B1 in treating and preventing colorectal cancer. Background Art

[0002] Colorectal cancer is one of the most common tumors in the world, and both genetic and environmental risk factors play an important role in the development of colorectal cancer (Lancet, 2019, 1467-1480).

[0003] Global cancer statistics in 2020 show that the incidence and mortality of colorectal cancer rank third (10%) and second (9.4%) among all tumors, respectively (CA Cancer J Clin, 2021, 209-249; World Health Organization, 2020). Currently, the best treatment for colorectal cancer is still radical surgery. However, since the clinical symptoms of the disease are hidden in the early stages and most patients only show symptoms in the late stages, many patients cannot be treated surgically when diagnosed with colorectal cancer because of the late stage of the disease, which seriously affects the patient's prognosis. Early molecular markers of colorectal cancer recurrence and metastasis tendency and clinical treatment interventions can improve prognosis. Therefore, further research on the molecular biological mechanisms of colorectal cancer progression is urgently needed to provide patients with more effective clinical treatment and prevention methods and reduce the mortality rate of colorectal cancer.

[0004] Cholesterol plays an important role in the pathogenesis of tumors, and scavenger receptor class B type 1 (SR-B1) is a key protein for reverse cholesterol transport and can regulate cholesterol homeostasis (Front Pharmacol, 2016, 7: 338). SR-B1 is a multi-ligand membrane receptor protein that is expressed in a high to low gradient along the gastrocolic axis in the intestine (J Lipid Res, 2001, 902-9). SR-B1 is highly expressed in a variety of tumors (Curr Opin Lipidol, 2017, 255-260; Front Pharmacol, 2016, 7: 326), but studies on the potential role of SR-B1 in colorectal cancer patients or animals have not been reported. Summary of the invention

[0005] The present invention uses SR-B1 gene knockout mice to study the effect of SR-B1 on azoxymethane / 2.5% dextran sulfate sodium (AOM / DSS)-induced colorectal cancer and APC min / +The effects of induced familial adenomatous polyposis model, and the role of SR-B1 gene knockout combined with anti-PD1 treatment in colorectal cancer. The tumor-suppressing effect of SR-B1 gene knockout was analyzed by comparing tumor load and histopathology, HE staining was used to compare the intestinal mechanical barrier, 16S rRNA high-throughput sequencing technology was used to detect changes in the abundance of intestinal flora in the feces of each group of mice, and flow cytometry was used to detect the levels of dendritic cells (DCs), tumor-associated macrophages (TAMs) and myeloid-derived suppressor cells (MDSCs) immune cells in the colorectal tissues of each group of mice. The results of this invention show that SR-B1 gene knockout has a significant anti-colorectal cancer effect, and SR-B1 gene knockout combined with anti-PD1 treatment significantly inhibits the development of colorectal cancer.

[0006] The purpose of the present invention is to provide application of scavenger receptor SR-B1 in treating and preventing colorectal cancer.

[0007] The SR-B1 of the present invention is highly expressed in colorectal cancer tissues.

[0008] SR-B1 gene knockout can inhibit tumor growth in AOM / DSS colorectal model mice, improve mouse survival, and improve the intestinal barrier.

[0009] SR-B1 gene knockout inhibits APC min / + Induced tumor growth in colorectal cancer model mice, improved mouse survival, and improved the intestinal barrier.

[0010] SR-B1 gene knockout reduced the levels of TAMs, M-MDSCs and G-MDSCs in colorectal cancer model mice and enhanced the anti-colorectal cancer immune response.

[0011] SR-B1 gene knockout combined with anti-PD1 therapy significantly inhibited the development of colorectal cancer and improved the intestinal mechanical barrier.

[0012] SR-B1 gene knockout can change the composition of intestinal flora in mice with colorectal cancer, increase the abundance of probiotics such as Akkermansia, Parabacteroides and Romboutsia, and reduce the abundance of pathogenic bacteria such as Desulfovibrio, Lachnoclostridium and Muribaculum, thereby exerting an anti-colorectal cancer effect. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 :Example 1 of the present invention SR-B1 expression analysis in colorectal cancer Figure 2 :Example 2 of the present invention: SR-B1 gene knockout inhibits tumor growth in AOM / DSS colorectal model mice Figure 3 :Example 3 of the present invention SR-B1 gene knockout inhibits APCmin / + Figure 1. Tumor growth in induced colorectal cancer model mice Figure 4 :Example 4 of the present invention SR-B1 gene knockout regulates the levels of DCs, TAMs, and MDSCs in the intestine of colorectal cancer model mice Figure 5 :Example 5 of the present invention SR-B1 gene knockout combined with anti-PD1 therapy against colorectal cancer Figure 6 :Example 6 of the present invention: Regulation of the intestinal flora of colorectal cancer model mice by SR-B1 gene knockout DETAILED DESCRIPTION

[0013] Example 1 Expression of SR-B1 in colorectal cancer Histochemical experiments revealed that the expression of SR-B1 in the colorectal tissues of colorectal cancer model mice was significantly increased compared with that in normal C57 mice (P < 0.001, Supplementary Figure 5). Figure 1 ).

[0014] Example 2 SR-B1 gene knockout inhibits tumor growth in AOM / DSS colorectal model mice Animal experiments were divided into AOM / DSS model group, AOM / DSS+SR-B1 - / + The mortality rate of mice in the AOM / DSS group was 66.7%, while that in the AOM / DSS+SR-B1 - / + The mortality rate of mice in the AOM / DSS group was 0. HE staining results showed that there were more crypt aberrations and dysplasia in the colorectal tissues of mice in the AOM / DSS model group. - / + The tumor burden of mice in the group was significantly reduced (P < 0.001, Figure 2 ).

[0015] Example 3 SR-B1 gene knockout inhibits APC min / + Tumor growth in colorectal cancer model mice Animal experiments were divided into APC min / + Model group, APC min / + +SR-B1- / + group, 10 mice in each group. APC min / + The mortality rate of mice in the model group was 50%, and APC min / + The mortality rate of mice in the +SR-B1- / + group was 0. HE staining results showed that APC min / + The colorectal tissues of mice in the model group showed more crypt aberrations and dysplasia. min / + Compared with the model group mice, APC min / + The tumor burden of mice in the +SR-B1- / + group was significantly reduced (P < 0.001, Figure 3).

[0016] Example 4 SR-B1 gene knockout regulates the levels of DCs, TAMs, and MDSCs in the intestine of colorectal cancer model mice Animal experiments were divided into AOM / DSS model group, AOM / DSS+SR-B1 - / + The results of flow cytometry detection of immune cell expression in colorectal tissues showed that compared with the AOM / DSS model group, the AOM / DSS+SR-B1 - / + There was no significant change in the level of DCs in the colorectal tissue of mice in the AOM / DSS+SR-B1 group. - / + The levels of TAM, M-MDSCs and G-MDSCs in the mice of the AOM / DSS model group were significantly decreased compared with those in the mice of the AOM / DSS model group (P<0.05, Supplementary Figure 4 ).

[0017] Example 5 Anti-colorectal cancer effect of SR-B1 gene knockout combined with anti-PD1 therapy The animal experiments were divided into AOM / DSS model group, AOM / DSS+SR-B1- / + group, anti-PD1 group, anti-PD-1+SR-B1 - / + Compared with the AOM / DSS model group, the AOM / DSS+SR-B1 - / + and anti-PD1+SR-B1 - / + The tumor burden of mice in the anti-PD1 group was significantly reduced (P < 0.01). HE staining results showed that the crypts in the colorectal tissues of mice in the anti-PD1 group were distorted and the lamina propria was dysplastic (attached Figure 5 ).

[0018] Example 5 Regulation of the intestinal flora of colorectal cancer model mice by SR-B1 gene knockout The animal experiments were divided into C57 blank control group, SR-B1 - / + Blank control group, AOM / DSS model group, AOM / DSS+SR-B1 - / + The results of 16S rRNA high-throughput sequencing showed that at the phylum level, compared with the C57 group, the abundance of Verrucomicrobia and Proteobacteria in the AOM / DSS model group was significantly reduced, while the abundance of Desulfobacteria was significantly increased (P < 0.05). - / +The abundance of Verrucomicrobia and Proteobacteria in the AOM / DSS group mice was significantly increased, while the abundance of Desulfobacteria was significantly decreased (P < 0.05). At the genus level, compared with the C57 group mice, the abundance of Akkermansia, Parabacteroides, and Romboutsia in the AOM / DSS model group mice was significantly decreased, while the abundance of Desulfovibrio, Lachnoclostridium, and Muribaculum was significantly increased (P < 0.05). Compared with the AOM / DSS model group mice, the abundance of AOM / DSS+SR-B1 - / + The abundance of Akkermansia, Parabacteroides, and Romboutsia in the mice of the AOM / DSS+SR-B1 group was significantly increased, while the abundance of Desulfovibrio, Lachnoclostridium, and Muribaculum was significantly decreased (P < 0.05). - / + The dominant bacterial flora of mice was Akkermansia, Bacteroides and other beneficial bacteria (see Appendix Figure 6 ). Intestinal flora analysis showed that SR-B1 gene knockout could change the composition of intestinal flora in colorectal cancer model mice and play an anti-colorectal cancer role.

Claims

1. Application of SR-B1 as a biomarker for colorectal cancer.

2. Application of SR-B1 as a therapeutic target for colorectal cancer.

3. A method for knocking out the SR-B1 gene for treating colorectal cancer induced by AOM / DSS inflammation, characterized in that: The animals are knocked out for the SR-B1 gene.

4. A method for treating APCmin / + induced colorectal cancer by knocking out the SR-B1 gene, characterized in that: The animals have a knockout SR-B1 gene and a mutated APC gene.

5. The SR-B1 gene knockout for treating inflammation-induced colorectal cancer according to claim 3, characterized in that: SR-B1 gene knockout can inhibit tumor growth in colorectal model mice induced by AOM / DSS inflammation, enhance anti-colorectal cancer immune response, and regulate the composition of intestinal flora in colorectal cancer mice.

6. The SR-B1 gene knockout for treating APCmin / + induced colorectal cancer according to claim 3, characterized in that: SR-B1 gene knockout can inhibit tumor growth in APCmin / +-induced colorectal cancer model mice.

7. A preparation for SR-B1 gene knockout combined with immunotherapy for colorectal cancer, characterized in that: SR-B1 gene knockout combined with anti-PD1 therapy significantly inhibits the development of colorectal cancer.

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