July 15 Cancer Research Highlights

PDF Version for Printing

Selected Articles from the July 15, 2007 Issue

The articles referenced in this Highlights section will be available online in HTML and PDF formats to all interested users at no charge until the next issue of Cancer Research is published. Click on the article title to view the complete article.

View the Table of Contents for the July 15 issue of Cancer Research.

Protein Panel Could Aid Early Detection of Lung Cancer

No known biomarkers are clinically efficient for early detection of lung cancer. Using a proteomics approach, Kim and colleagues identified a panel of 22 proteins that are secreted apically from squamous metaplastic but not normal phenotype primary bronchial epithelial cells. Expression of certain proteins, such as SCCA1 and SCCA2, gradually increased during cancer progression and remained elevated in a subset of lung cancers. These results suggest that proteins secreted from abnormally differentiated metaplastic squamous epithelial cells could be biomarkers for detecting lung cancer.

Disruption of Cdc25A Inhibits Tumorigenesis

Cyclin-dependent kinases (CDKs) play central roles in promoting progression of the cell cycle in all eukaryotic cells, and CDC25A phosphatase activates multiple CDKs during cell cycle progression. Inactivation of CDC25A by ubiquitin-mediated degradation is a major mechanism of DNA damage-induced S-G₂ checkpoint. Although increased CDC25A expression has been reported in human cancer, whether CDC25A activation is a critical rate-limiting step of carcinogenesis is unclear. Testing of a Cdc25A-null mouse strain suggests that Cdc25A plays a rate-limiting role in transformation and tumor initiation mediated by ras activation.

Diabetes Drug Reduces p53-Deficient Tumors

The effects of the antidiabetic drug metformin on tumor growth were studied using paired isogenic colon cancer cell lines HCT116p53^+/+ and HCT116p53^–/–. After metformin treatment, there was increased apoptosis in p53^–/– tumor sections and enhanced susceptibility of p53^–/– cells to apoptosis in vitro when nutrient deprived. These results suggest a potential treatment for patients with p53-deficient tumors, which are often resistant to chemotherapy or radiotherapy.

The precision of tumorresection affects prognosis, but intraoperative identification of tumor margins or small foci of cancer cells remains imprecise. Veiseh and colleagues developed a molecular imaging bioconjugate composed of chlorotoxin (CTX) and Cy5.5. The probe delineated malignant glioma, medulloblastoma, prostate cancer, intestinal cancer, and sarcoma from adjacent normal tissue in mice. Metastatic cancer foci as small as a few hundred cells were detected in lymph channels. CTX:Cy5.5 could greatly improve intraoperative detection and resection of malignancies.

Plant Flavone Suppresses Prostate Carcinogenesis