Developmental Pluripotency-Associated 4 Increases Aggressiveness of Pituitary Neuroendocrine Tumors by Enhancing Cell Stemness

The Oncogenic Role of Dppa4 in Pituitary Neuroendocrine Tumors

Academic Background

Pituitary Neuroendocrine Tumors (PitNETs) are common intracranial tumors that often exhibit hormone-secreting functions and are a significant cause of hypogonadism and infertility in humans. Although most PitNETs can be controlled through surgery and medication, some tumors exhibit insensitivity to treatment or recurrence, and even demonstrate aggressive behaviors such as extensive infiltration of surrounding tissues or distant metastasis. Currently, the mechanisms underlying the aggressiveness of PitNETs remain unclear, particularly the role of tumor stem cells in this process.

Recent studies suggest that tumor stem cells may play a crucial role in the aggressiveness and drug resistance of PitNETs. The embryonic stem cell regulatory gene Dppa4 (Developmental Pluripotency-Associated 4) is overexpressed in certain cancers, but its role in the aggressiveness of PitNETs has not been fully elucidated. Therefore, this study aims to explore the molecular mechanisms by which Dppa4 contributes to the aggressiveness of PitNETs, particularly how it regulates the characteristics of tumor stem cells to promote tumor invasiveness.

Source of the Paper

This paper was co-authored by Shaista Chaudhary, Ujjal Das, Shaima Jabbar, Omkaram Gangisetty, Bénédicte Rousseau, Simon Hanft, and Dipak K. Sarkar, affiliated with the Endocrine Program in the Department of Animal Sciences at Rutgers, the State University of New Jersey, and the Pituitary Tumor Program at the Rutgers Cancer Institute of New Jersey. The paper was published on August 2, 2024, in the journal Neuro-Oncology, titled “Developmental Pluripotency-Associated 4 Increases Aggressiveness of Pituitary Neuroendocrine Tumors by Enhancing Cell Stemness.”

Research Process

1. Animal Models and Cell Culture

The study utilized two models: a rat pituitary tumor model and a human pituitary tumor model. In the rat model, researchers used female Fischer rats exposed to prenatal alcohol (Prenatal Alcohol Exposure, PAE), which developed aggressive PitNETs following estrogen treatment. In the human model, researchers used aggressive pituitary tumor cells from surgical patients.

  • Animal Model: PAE rats were fed an alcohol-containing liquid diet during pregnancy, followed by bilateral ovariectomy at 60 days postpartum and implantation of estrogen capsules to induce pituitary tumors. Pituitary tumor tissues were collected 120 days later for experiments.
  • Cell Culture: Primary cell cultures were established from rat and human pituitary tumor tissues, and CRISPR technology was used to knock out and knock in the Dppa4 gene.

2. Molecular and Cellular Experiments

Researchers employed various molecular, cellular, and epigenetic techniques to investigate the role of Dppa4 in the aggressiveness of PitNETs.

  • RNA Sequencing and Gene Expression Analysis: RNA sequencing (RNA-seq) was used to analyze gene expression changes in PAE rats and human pituitary tumor cells, revealing significant upregulation of Dppa4 in aggressive tumors.
  • CRISPR Gene Editing: CRISPR technology was used to knock out the Dppa4 gene, resulting in significantly reduced proliferation, migration, and tumorigenic potential of tumor cells. Conversely, overexpression of Dppa4 enhanced these characteristics.
  • Chromatin Immunoprecipitation (ChIP) Assay: ChIP experiments showed that Dppa4 binds to key promoter regions of the Wnt signaling pathway, indicating that Dppa4 enhances tumor stem cell characteristics by regulating the Wnt/β-catenin signaling pathway.

3. Epigenetic Mechanisms

The study also explored the epigenetic mechanisms underlying Dppa4 overexpression. RNA-seq and ChIP experiments revealed that PAE significantly increased the H3K4me3 (trimethylation of lysine 4 on histone H3) mark at the Dppa4 promoter region, suggesting that Dppa4 expression is epigenetically regulated.

  • H3K4me3 Inhibitor Experiment: Treatment with the H3K4me3 inhibitor MM-102 significantly reduced Dppa4 expression, further confirming the critical role of H3K4me3 in regulating Dppa4 expression.

Key Findings

  1. Dppa4 is Overexpressed in Aggressive PitNETs: RNA-seq and Western blot experiments demonstrated that Dppa4 is significantly upregulated in PAE rats and human aggressive pituitary tumor cells, correlating with increased expression of tumor stem cell markers (e.g., Oct4, Sox2, Klf4).

  2. Dppa4 Enhances Tumor Stem Cell Characteristics: CRISPR-mediated knockout of Dppa4 significantly reduced tumor cell proliferation, migration, and tumorigenic potential, while overexpression of Dppa4 enhanced these characteristics. This indicates that Dppa4 promotes PitNET aggressiveness by regulating tumor stem cell properties.

  3. Dppa4 Acts Through the Wnt/β-catenin Signaling Pathway: ChIP assays and gene expression analysis showed that Dppa4 binds to key promoter regions of the Wnt signaling pathway and enhances tumor stem cell characteristics by activating the Wnt/β-catenin signaling pathway.

  4. Epigenetic Regulation Mechanism: PAE increased the H3K4me3 mark at the Dppa4 promoter region, indicating that Dppa4 expression is epigenetically regulated. The H3K4me3 inhibitor MM-102 significantly reduced Dppa4 expression, further validating this mechanism.

Conclusions and Significance

This study demonstrates that Dppa4 plays a critical role in the aggressiveness of PitNETs by regulating tumor stem cell characteristics and activating the Wnt/β-catenin signaling pathway to promote tumor growth and invasion. Additionally, Dppa4 expression is epigenetically regulated, particularly through increased H3K4me3 marks. These findings provide new potential therapeutic targets for PitNETs, especially in the development of drugs targeting Dppa4 and its regulatory pathways.

Research Highlights

  1. Oncogenic Role of Dppa4: This study is the first to reveal the critical role of Dppa4 in the aggressiveness of PitNETs, particularly its promotion of tumor growth and invasion by regulating tumor stem cell characteristics.

  2. Regulation of the Wnt/β-catenin Signaling Pathway: The study found that Dppa4 enhances tumor stem cell characteristics by activating the Wnt/β-catenin signaling pathway, offering new insights into the molecular mechanisms of PitNETs.

  3. Epigenetic Regulation Mechanism: The study revealed that PAE regulates Dppa4 expression by increasing H3K4me3 marks, providing new evidence for the role of epigenetics in tumorigenesis.

Additional Valuable Information

The study also found that Dppa4 may play a similar role in other cancers, such as non-small cell lung cancer, suggesting that Dppa4 could be a key gene broadly involved in tumorigenesis and progression. Future research could further explore the role of Dppa4 in other types of cancer and its potential therapeutic applications.


Through this research, scientists have not only uncovered the oncogenic mechanisms of Dppa4 in PitNETs but also provided new insights and potential targets for future cancer treatments. This discovery holds promise for breakthroughs in the treatment of aggressive pituitary tumors.