Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 May;28(10):e18397.
doi: 10.1111/jcmm.18397.

SAP deletion promotes malignant insulinoma progression by inducing CXCL12 secretion from CAFs via the CXCR4/p38/ERK signalling pathway

Guangchun Jiang  1 , Shuo Xu  1 , Xiaobin Mai  1 , Juan Tu  1 , Le Wang  1 , Lijing Wang  1 , Yaping Zhan  1 , Yan Wang  1 , Qianqian Zhang  1 , Lingyun Zheng  1 , Jiangchao Li  1 , Pei Tang  1 , Cuiling Qi  1
Affiliations

SAP deletion promotes malignant insulinoma progression by inducing CXCL12 secretion from CAFs via the CXCR4/p38/ERK signalling pathway

Guangchun Jiang et al. J Cell Mol Med. 2024 May.

Abstract

Malignant insulinoma is an extremely rare type of functioning pancreatic neuroendocrine tumour with a high degree of malignancy and a high incidence of metastasis. However, it is still unclear how malignant insulinomas develop and metastasize. Serum amyloid P component (SAP), a member of the pentraxin protein family, is an acute-phase protein secreted by liver cells. The role of SAP in insulinoma and the related mechanism are still unknown. To determine the effect of SAP on insulinoma, we crossed Rip1-Tag2 mice, which spontaneously develop insulinoma, and SAP knockout (KO) mice to generate Rip1-Tag2;SAP-/- mice. We found that SAP deletion significantly promoted the growth, invasion and metastasis of malignant insulinoma through C-X-C motif chemokine ligand 12 (CXCL12) secreted by cancer-associated fibroblasts (CAFs). Further study showed that SAP deletion promoted CXCL12 secretion by CAFs through the CXCR4/p38/ERK signalling pathway. These findings reveal a novel role and mechanism of SAP in malignant insulinoma and provide direct evidence that SAP may be a therapeutic agent for this disease.

Keywords: CAF; CXCL12; SAP; insulinoma growth; insulinoma metastasis; malignant insulinoma.

PubMed Disclaimer

Conflict of interest statement

The authors confirm that there are no conflicts of interest.

Figures

FIGURE 1
FIGURE 1
The effect of serum amyloid P component (SAP) on insulinoma growth. (A) The survival times of Rip1‐Tag2 and Rip1‐Tag2;SAP−/− mice. (B, C) Tumour numbers (B) and tumour volumes (C) in Rip1‐Tag2 and Rip1‐Tag2;SAP−/− mice. (D, E) Representative immunohistochemical images of insulinomas from Rip1‐Tag2 and Rip1‐Tag2;SAP−/− mice. Statistical analysis demonstrated that SAP deletion promoted tumour cell proliferation. The results are representative of at least four sections per mouse from a minimum of three mice per group. (F) The survival times of Rip1‐Tag2 and Rip1‐Tag2;SAP‐Tg mice. (G, H) Tumour numbers (G) and tumour volumes (H) in Rip1‐Tag2 and Rip1‐Tag2;SAP‐Tg mice. * p < 0.05; *** p < 0.001. Scale bar = 50 μm.
FIGURE 2
FIGURE 2
Serum amyloid P component (SAP) deficiency promotes tumour invasion. (A) Haematoxylin and eosin staining of a noninvasive insulinoma, a focally invasive IC1 insulinoma, and a broadly invasive IC2 insulinoma from a Rip1‐Tag2 mouse and a Rip1‐Tag2;SAP−/− mouse. (B) Quantification of tumour invasiveness, shown as the percentages of noninvasive tumours, IC1 tumours, and IC2 tumours in Rip1‐Tag2 and Rip1‐Tag2;SAP−/− mice at 12 weeks of age. * p < 0.05; ** p < 0.01. Scale bar = 100 μm.
FIGURE 3
FIGURE 3
Serum amyloid P component (SAP) deficiency promotes insulinoma metastasis. (A, C, E) Representative haematoxylin and eosin staining images of the livers, lungs and intestines from Rip1‐Tag2 mice and Rip1‐Tag2; SAP−/− mice. (B, D, F) The percentages of mice with liver, lung and intestinal metastasis were calculated. Scale bar = 50 μm.
FIGURE 4
FIGURE 4
Serum amyloid P component (SAP) deletion increases the amount of CXCL12 secreted by CAFs. (A) The protein chip array data demonstrated that the CXCL12 concentration was increased in the serum of Rip1‐Tag2;SAP−/− mice compared with the serum of Rip1‐Tag2 mice. (B) Serum concentration of CXCL12 in Rip1‐Tag2 mice and Rip1‐Tag2;SAP−/− mice. (C) The stably transduced cell lines were processed through the indicated workflow. (D, E) The protein expression of α‐SMA was increased after L929 cells were treated with CM derived from NIT‐1 cells for 72 h. (F, G) SAP RNA interference significantly inhibited SAP protein expression in CAFs. (H) SAP knockdown significantly increased the CXCL12 concentration in CAF culture medium. (I) Representative immunofluorescent images of CXCL12 and α‐SMA for CAFs in the insulinoma tissues from Rip1‐Tag2 mice. CXCL12 expressed in α‐SMA positive cells in the tumour tissues of Rip1‐Tag2. Scale bar = 25 μm. * p < 0.05; ** p < 0.01.
FIGURE 5
FIGURE 5
Effect of SAP knockdown on NIT‐1 cell migration and invasion through CAF‐derived CXCL12. (A) Representative images of migrated NIT‐1 cells. CXCL12 significantly promoted NIT‐1 cell migration. Furthermore, the ability of NIT‐1 cells treated with CXCL12 to migrate was reduced after serum amyloid P component (SAP) treatment. (B) Representative images of invaded NIT‐1 cells. CXCL12 significantly promoted NIT‐1 cell invasion. Furthermore, the ability of NIT‐1 cells treated with CXCL12 to invade was reduced after SAP treatment. (C) Representative images of migrated NIT‐1 cells. The ability of NIT‐1 cells to migrate was significantly increased after SAP was silenced. (D) Representative images of invaded NIT‐1 cells. The ability of NIT‐1 cells to invade was significantly increased after SAP was silenced. * p < 0.05; ** p < 0.01; *** p < 0.001. Scale bar = 50 μm.
FIGURE 6
FIGURE 6
Effect of CXCL12 on the p38/ERK signalling pathway in NIT‐1 and RIN‐m5F cells. (A, B) CXCL12 significantly induced CXCR4, p‐p38 and p‐ERK protein expression in NIT‐1 cells but did not affect p38 and ERK expression. (C, D) CXCL12 significantly increased CXCR4, p‐p38 and p‐ERK protein expression in RIN‐m5F cells but did not affect p38 and ERK expression. * p < 0.05; ** p < 0.01; *** p < 0.001.
FIGURE 7
FIGURE 7
Mechanistic diagram. Schematic diagram of the role of serum amyloid P component (SAP) in insulinoma and the mechanism by which SAP deletion inhibits malignant insulinoma progression.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Pelengaris S, Khan M. Oncogenic co‐operation in β‐cell tumorigenesis. Endocr Relat Cancer. 2001;8(4):307‐314. - PubMed
    1. Oberg K, Eriksson B. Endocrine tumours of the pancreas. Best Pract Res Clin Gastroenterol. 2005;19(5):753‐781. - PubMed
    1. Pilling D, Gomer RH. The development of serum amyloid P as a possible therapeutic. Front Immunol. 2018;9:2328. - PMC - PubMed
    1. Bottazzi B, Inforzato A, Messa M, et al. The pentraxins PTX3 and SAP in innate immunity, regulation of inflammation and tissue remodelling. J Hepatol. 2016;64(6):1416‐1427. - PMC - PubMed
    1. Xi D, Luo T, Xiong H, et al. SAP: structure, function, and its roles in immune‐related diseases. Int J Cardiol. 2015;187:20‐26. - PubMed

MeSH terms

LinkOut - more resources