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[FOXC1 Knockdown Reverses Gefitinib Resistance in Non-small Cell Lung Cancer]
Cong Peng1, Pan Li2, Mingqiang Yang2
1Department of Pathology, Affiliated Cancer Hospital of Guangzhou Medical University, Guangzhou 510095, China.
Background:
Lung cancer is the malignant tumor with the highest incidence and mortality in China, among which non-small cell lung cancer (NSCLC) accounts for about 80%. Epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) targeted therapy has been playing an important role in treatment of NSCLC. However, unavoidable therapeutic resistance significantly limits the clinical efficacy of EGFR-TKI. As a key member of the forkhead box protein family, FOXC1 is aberrantly expressed in NSCLC and involved in NSCLC progression. The aim of this work is to investigate the effect and potential mechanism of FOXC1 on gefitinib resistance in NSCLC.
Methods:
Western blot was performed to assess the expression of FOXC1 protein in HCC827/GR cells. Immunohistochemistry (IHC) assays were performed in human NSCLC tissues with gefitinib resistance. HCC827/GR cells were transfected with shRNA specifically targeting FOXC1 mRNA and stable cell lines were established. The effects of FOXC1 on cell viability and apoptosis were analyzed using a new methyl thiazolyl tetrazolium assay (MTS assay) and flow cytometry. Self-renewal ability was determined by mammosphere-formation analysis. Quantitative real-time PCR (qRT-PCR) and Western blot were employed to detect the expression of SOX2, Nanog, OCT4 and CD133. Flow cytometry analysis were further used to detect the level of CD133. IHC assays were used to detect the levels of SOX2 and CD133 in NSCLC tissues with genfitiinb resistance. Correlations of the expressions of FOXC1, CD133 and SOX2 with each other in lung adenocarcinoma samples were analyzed based on The Cancer Genome Atlas (TCGA) database.
Results:
The expression of FOXC1 is significantly increased in HCC827/GR cells compared with HCC827 cells (P<0.05). IHC results showed FOXC1 was highly expressed in NSCLC tissues with gefitinib resisitance. Knockdown of FOXC1 significantly increased the sensitivity of HCC827/GR cells to gefitinib. The cell viability was decreased and the apoptosis was promoted (P<0.05). Moreover, FOXC1 knockdown apparently inhibited the expression of SOX2 and CD133, and decreased the mammosphere-formation capacity in HCC827/GR cells. In NSCLC tissues with gefitinib resistance, the expressions of SOX2 and CD133 were significantly higher compared with gefitinib-sensitive tissues (P<0.01). Meanwhile, the expressions of FOXC1, CD133 and SOX2 with each other were positively correlated (P<0.05).
Conclusions:
FOXC1 could increase gefitinib resitance in NSCLC, by which mechanism is related to the regulation of cancer stem cell properties.
Insights
Forkhead box protein C1 (FOXC1) promotes gefitinib resistance in non-small cell lung cancer (NSCLC) by enhancing cancer stem cell properties. Targeting FOXC1 may overcome therapeutic resistance in NSCLC patients.
Area of Science:
- Molecular Oncology
- Cancer Therapeutics
- Biomarker Discovery
Background:
- Non-small cell lung cancer (NSCLC) is a leading cause of cancer mortality in China, with epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) showing clinical importance.
- Therapeutic resistance to EGFR-TKIs significantly limits treatment efficacy in NSCLC.
- Aberrant expression of Forkhead box protein C1 (FOXC1) is implicated in NSCLC progression and may influence treatment response.
Purpose of the Study:
- To investigate the role of FOXC1 in mediating gefitinib resistance in NSCLC.
- To elucidate the underlying mechanisms by which FOXC1 affects gefitinib resistance, focusing on cancer stem cell properties.
Main Methods:
- Assessed FOXC1 protein expression via Western blot in gefitinib-resistant NSCLC cells (HCC827/GR) and human NSCLC tissues using immunohistochemistry (IHC).
- Utilized shRNA to knockdown FOXC1 in HCC827/GR cells and evaluated effects on cell viability (MTS assay), apoptosis (flow cytometry), and self-renewal (mammosphere formation).
- Quantified expression of cancer stem cell markers (SOX2, Nanog, OCT4, CD133) using qRT-PCR, Western blot, and flow cytometry; analyzed correlations with FOXC1, CD133, and SOX2 in TCGA lung adenocarcinoma data.
Main Results:
- FOXC1 expression was significantly elevated in gefitinib-resistant NSCLC cells and tissues compared to sensitive counterparts.
- FOXC1 knockdown resensitized resistant cells to gefitinib, decreasing viability and increasing apoptosis.
- FOXC1 inhibition suppressed cancer stem cell markers (SOX2, CD133) and self-renewal capacity, with positive correlations observed between FOXC1, SOX2, and CD133 expression in NSCLC.
Conclusions:
- FOXC1 plays a crucial role in conferring gefitinib resistance in NSCLC.
- The mechanism involves the regulation of cancer stem cell properties, including self-renewal and expression of key stemness markers.
- Targeting FOXC1 represents a potential strategy to overcome EGFR-TKI resistance in NSCLC.
