Related Experiment Video
Updated: Apr 1, 2026
Utilizing Murine Inducible Telomerase Alleles in the Studies of Tissue Degeneration/Regeneration and Cancer
Published on: April 13, 2015
Suppression of PinX1 resulted in telomere dysfunction and enhanced radiosensitivity in osteosarcoma cell lines
Abstract:
Telomeres have emerged as a promising and important factor modulating cellular and organism responses to ionizing radiation (IR). Pin2/TRF1 interacting protein X1 (PinX1) is an intrinsic telomerase inhibitor and a putative tumor suppressor gene in human cancers. The aim of this study is to investigate the role PinX1 in osteosarcoma (OS) radioresistance. A telomerase-positive OS cell line Saos-2 and a telomerase-negative OS cell line U2OS were used. PinX1 shRNA lentiviral vetors were constructed and transfected to cells. PinX1 expression was determined by real-time quantitative PCR (qPCR) and Western blotting. Relative telomere length (RTL) was detected by using qPCR. Flow cytometric analysis was used to detect cell cycle and apoptosis. Radiosensitivity was determined by colony formation assay. Data showed that, PinX1 knockdown resulted in telomere shortening, G1 phase arrest, increased apoptosis and enhanced IR sensitivity both in Saos-2 and U2OS cell lines, regardless of telomerase status. Our study concluded that PinX1 could serve as a novel predictor for radiotherapy response to OS patients, and the pathway of PinX1-mediated telomere stability might represent a new target to improve the radiotherapy effect of OS.
Insights
Pin2/TRF1 interacting protein X1 (PinX1) knockdown shortens telomeres, increases apoptosis, and enhances radiosensitivity in osteosarcoma cells. PinX1 may predict radiotherapy response and serve as a therapeutic target.
Area of Science:
- Oncology
- Molecular Biology
- Radiotherapy Research
Background:
- Telomeres and their associated proteins play a crucial role in cellular responses to ionizing radiation (IR).
- Pin2/TRF1 interacting protein X1 (PinX1) functions as an intrinsic telomerase inhibitor and is implicated as a tumor suppressor in human cancers.
- Understanding the role of PinX1 in radioresistance is critical for improving cancer treatment strategies.
Purpose of the Study:
- To investigate the role of PinX1 in the radioresistance of osteosarcoma (OS).
- To determine if PinX1 modulation affects radiosensitivity irrespective of telomerase status in OS cells.
Main Methods:
- Utilized telomerase-positive (Saos-2) and telomerase-negative (U2OS) osteosarcoma cell lines.
- Generated PinX1 knockdown using shRNA lentiviral vectors.
- Assessed PinX1 expression (qPCR, Western blot), relative telomere length (qPCR), cell cycle and apoptosis (flow cytometry), and radiosensitivity (colony formation assay).
Main Results:
- PinX1 knockdown led to significant telomere shortening in both cell lines.
- Reduced PinX1 expression induced G1 phase arrest and increased apoptosis.
- Knockdown of PinX1 consistently enhanced radiosensitivity in both Saos-2 and U2OS cells, independent of their telomerase status.
- These effects were observed regardless of the cells' endogenous telomerase activity.
Conclusions:
- PinX1 plays a significant role in modulating osteosarcoma radioresistance.
- PinX1 knockdown enhances radiosensitivity by inducing telomere shortening, cell cycle arrest, and apoptosis.
- PinX1 may serve as a novel predictive biomarker for radiotherapy response in osteosarcoma patients.
- Targeting the PinX1-mediated telomere stability pathway presents a potential strategy to improve radiotherapy efficacy in osteosarcoma.
Related Concept Videos
02:23Abnormal Proliferation
02:15Replicative Cell Senescence
01:12Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
01:05Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
02:53Adaptive Mechanisms in Cancer Cells
Some of the advantages that cancer cells have on normal cells include - enhanced ability to divide without terminally differentiating, induce new blood vessel formation,...