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Updated: Mar 22, 2026
The Soft Agar Colony Formation Assay
Published on: October 27, 2014
SOSTDC1 is down-regulated in non-small cell lung cancer and contributes to cancer cell proliferation
Lei Liu1,2, Shanshan Wu1,2, Yi Yang1,3
1Key Laboratory of Tropical Disease Control, Ministry of Education, Sun Yat-sen University, Guangzhou, 510080 Guangdong China.
Background:
Non-small cell lung cancer (NSCLC) is the most commonly diagnosed and fatal cancer worldwide. Sclerostin domain containing protein 1 (SOSTDC1) has been found to be tumor-suppressive in several types of cancers. However, the expression level and biological functions of SOSTDC1 in NSCLC remain unknown. Our current study aimed to identify the biological significance of SOSTDC1 in NSCLC.
Results:
We found that SOSTDC1 was significantly down-regulated in NSCLC. Moreover, patients with higher expression of SOSTDC1 had a significant better prognosis than those with lower SOSTDC1 expression. Ectopic expression of SOSTDC1 in NSCLC cell lines A549 and NCI-H520 could inhibit proliferation as shown by MTT, colony formation, soft agar and EdU incorporation assays in vitro. Furthermore, A549 cells stably expressing ectopic SOSTDC1 grew more slowly and formed smaller tumors than vector-control cells in vivo. Mechanistic studies demonstrated that SOSTDC1 over-expression led to increased p21Cip and p27Kip levels, thereby decreasing Rb phosphorylation status and E2F transcription activity.
Conclusions:
SOSTDC1 is down-regulated in NSCLC, and its expression level is indicative of clinical outcome of patients with the disease. SOSTDC1 might represent a tumor suppressor through inhibiting the proliferation of NSCLC cells by regulating p21Cip and p27Kip, which in turn affects Rb-E2F signaling.
Insights
Sclerostin domain containing protein 1 (SOSTDC1) is reduced in non-small cell lung cancer (NSCLC), acting as a tumor suppressor. Higher SOSTDC1 levels correlate with better patient prognosis and inhibited tumor growth.
Area of Science:
- Oncology
- Molecular Biology
- Cancer Research
Background:
- Non-small cell lung cancer (NSCLC) is a leading cause of cancer death globally.
- Sclerostin domain containing protein 1 (SOSTDC1) exhibits tumor-suppressive roles in various cancers.
- The role of SOSTDC1 in NSCLC pathogenesis was previously uncharacterized.
Purpose of the Study:
- To investigate the expression patterns of SOSTDC1 in NSCLC.
- To elucidate the biological functions and clinical significance of SOSTDC1 in NSCLC.
- To explore the underlying molecular mechanisms of SOSTDC1's action in NSCLC.
Main Methods:
- Quantitative analysis of SOSTDC1 expression in NSCLC tissues and cell lines.
- In vitro proliferation assays (MTT, colony formation, soft agar, EdU incorporation) with ectopic SOSTDC1 expression.
- In vivo tumor growth studies using NSCLC xenografts.
- Western blot analysis to assess key protein levels (p21Cip, p27Kip, Rb phosphorylation, E2F activity).
Main Results:
- SOSTDC1 expression is significantly downregulated in NSCLC.
- Reduced SOSTDC1 correlates with poorer patient prognosis.
- Ectopic SOSTDC1 expression inhibits NSCLC cell proliferation and tumor growth in vitro and in vivo.
- SOSTDC1 overexpression increases p21Cip and p27Kip, decreases Rb phosphorylation, and reduces E2F activity.
Conclusions:
- SOSTDC1 functions as a tumor suppressor in NSCLC.
- SOSTDC1 downregulation is a marker for poor prognosis in NSCLC patients.
- SOSTDC1 inhibits NSCLC proliferation via the p21Cip/p27Kip-mediated regulation of the Rb-E2F pathway.
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