Related Experiment Video
Updated: Mar 12, 2026
Macrophage Differentiation and Polarization into an M2-Like Phenotype using a Human Monocyte-Like THP-1 Leukemia Cell Line
Published on: August 2, 2021
PLD4 promotes M1 macrophages to perform antitumor effects in colon cancer cells
Long Gao1, Yan Zhou1, Shu-Xian Zhou1
1The Gastroenterology Tumor and Microenvironment Laboratory, Department of Gastroenterology, The First Affiliated Hospital of Chengdu Medical College, Chengdu Medical College, Chengdu, Sichuan 610041, P.R. China.
Abstract:
Phospholipase D4 (PLD4) is a newly identified protein expressed in microglia. However, the function of PLD4 in tumor-associated macrophages (TAMs) is unknown. In the present study, we revealed that the expression of PLD4 was located in macrophages in the colon cancer mesenchymal and lymph nodes as shown by immunohistochemical analysis. furthermore, its expression was associated with clinical staging of colon cancer. Then, THP-1 as a cell model induced into TAMs. Western blot and RT-PCR analysis showed that PLD4 was mainly presented in M1 phenotype TAMs. The secretion of pro-inflammatory cytokines in M1 macrophages was significantly reduced after the expression of PLD4 inhibited by PLD4-siRNA. Furthermore, co-cultured with condition-medium from control or PLD4-siRNA M1 macrophages for 24 h, cell apoptosis, cycle and proliferation of cancer cells improved compared to control. These results indicated that PLD4 could be involved in the activation process of M1 phenotype macrophages.
Insights
Phospholipase D4 (PLD4) is expressed in M1 phenotype tumor-associated macrophages (TAMs) and influences colon cancer progression. Inhibiting PLD4 in M1 TAMs reduces pro-inflammatory cytokines, impacting cancer cell apoptosis and proliferation.
Area of Science:
- Immunology
- Oncology
- Molecular Biology
Background:
- Phospholipase D4 (PLD4) is a newly identified protein primarily expressed in microglia.
- The role of PLD4 in tumor-associated macrophages (TAMs) within the tumor microenvironment remains largely uncharacterized.
- Understanding PLD4's function in TAMs could reveal novel therapeutic targets in cancer.
Purpose of the Study:
- To investigate the expression and function of Phospholipase D4 (PLD4) in macrophages within the context of colon cancer.
- To determine the specific TAM phenotype associated with PLD4 expression.
- To elucidate the impact of PLD4 on TAM-mediated inflammatory responses and their effect on colon cancer cells.
Main Methods:
- Immunohistochemical analysis to detect PLD4 expression in colon cancer tissues and lymph nodes.
- THP-1 cells were differentiated into TAMs and characterized using Western blot and RT-PCR.
- PLD4 expression was inhibited using PLD4-siRNA in M1 TAMs.
- Pro-inflammatory cytokine secretion was measured.
- Colon cancer cell apoptosis, cell cycle, and proliferation were assessed after co-culture with conditioned medium from manipulated M1 TAMs.
Main Results:
- PLD4 expression was observed in macrophages within the colon cancer mesenchymal and lymph nodes, correlating with clinical staging.
- PLD4 was predominantly found in the M1 phenotype TAMs.
- Inhibition of PLD4 in M1 TAMs led to a significant reduction in pro-inflammatory cytokine secretion.
- Conditioned medium from PLD4-inhibited M1 TAMs enhanced colon cancer cell apoptosis, altered cell cycle, and reduced proliferation compared to controls.
Conclusions:
- PLD4 is expressed in M1 phenotype TAMs and its expression is associated with colon cancer progression.
- PLD4 plays a role in the activation and inflammatory function of M1 TAMs.
- Modulating PLD4 expression in M1 TAMs affects the tumor microenvironment and influences colon cancer cell behavior, suggesting PLD4 as a potential therapeutic target.
