High calpain-1 expression predicts a poor clinical outcome and contributes to tumor progression in pancreatic cancer patients
Pancreatic cancer (PC) is a highly aggressive and metastatic disease, with an elevated mortality rate. It is, therefore, crucial to assess factors affecting the prognosis of PC patients. Meanwhile, calpain-1 is associated with malignant tumor progression and metastasis. Thus, it is meaningful to evaluate the relationship between calpain-1 and PC.
Materials and methods
Calpain-1 protein expression was assessed by immunohistochemistry in 96 pancreatic cancer samples and paired adjacent non-cancerous specimens. In addition, calpain-1 protein levels were assessed in six PC cell lines by western blot (WB). Next, PC cells were transfected with calpain-1 siRNA, and silencing was confirmed by WB. Finally, cell proliferation, colony formation, migration and invasion assays, and cell apoptosis analysis were performed to examine the effects of calpain-1 knockdown on proliferation, growth, apoptosis, migration, and invasion in PC cells.
The results showed that calpain-1 was overexpressed in PC tissues and cells. Meanwhile, calpain-1 overexpression was associated with tumor site (P = 0.029), metastasis (P = 0.000), and TNM stage (P = 0.000), but showed no associations with histological grade (P = 0.396), age (P = 0.809), sex (P = 1.000), and lesion size (P = 0.679). The Kaplan–Meier method demonstrated that the low calpain-1 expression group had increased overall survival (OS) compared with patients expressing high calpain-1 levels (28.7 ± 4.1 vs. 17.0 ± 2.3 months) (P = 0.005). Besides, calpain-1 in PC cells was successfully silenced by liposome-mediated RNA interference, resulting in reduced cell growth, invasion, and metastasis in PC cells, with no effect on apoptosis.
The above findings suggest that calpain-1 should be considered a potential biomarker for PC prognosis and therapy.
KeywordsPancreatic cancer Calpain-1 Prognosis Proliferation Colony formation Migration Invasion
This study received research funding from the Zhejiang Provincial Natural Science Foundation of China (Y2100546).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All the experimental procedures have been approved by the ethics committee at The Second Affiliated Hospital and Yuying Children’s Hospital of Wenzhou Medical University.
Resected PC specimens were obtained together with the paired adjacent non-tumor tissue samples from 96 patients at the Second Affiliated Hospital and the First Affiliated Hospital of Wenzhou Medical University, with signed approval obtained from the involved patients.