Limited-stage small-cell lung cancer: the current status of combined-modality therapy

NOV-002, a mimetic of glutathione disulfide

BACKGROUND

Oxidative signaling to modulate redox-sensitive cell functions is a heretofore unexploited approach to developing new drugs for poorly treated oncology indications, where current therapies are often only palliative and accompanied by severe toxicities.

OBJECTIVE

Clinical and non-clinical findings with NOV-002 (a mimetic of glutathione disulfide that represents such an approach) are reviewed and evaluated.

METHODS

Published data on NOV-002 along with unpublished information from the drug's sponsor were reviewed. Literature analysis also focused on protein S-glutathionylation as a regulatory mechanism, particularly in relation to cell signaling, proliferation and cytoskeletal architecture.

RESULTS/CONCLUSION

NOV-002 is a mechanistically novel agent with potential for ameliorating hematologic toxicity and enhancing efficacy when used in combination with standard chemotherapy to treat cancer patients.

Oct-4 expression maintained cancer stem-like properties in lung cancer-derived CD133-positive cells

CD133 (prominin-1), a 5-transmembrane glycoprotein, has recently been considered to be an important marker that represents the subset population of cancer stem-like cells. Herein we report the isolation of CD133-positive cells (LC-CD133⁺) and CD133-negative cells (LC-CD133⁻) from tissue samples of ten patients with non-small cell lung cancer (LC) and five LC cell lines. LC-CD133⁺ displayed higher Oct-4 expressions with the ability to self-renew and may represent a reservoir with proliferative potential for generating lung cancer cells. Furthermore, LC-CD133⁺, unlike LC-CD133⁻, highly co-expressed the multiple drug-resistant marker ABCG2 and showed significant resistance to chemotherapy agents (i.e., cisplatin, etoposide, doxorubicin, and paclitaxel) and radiotherapy. The treatment of Oct-4 siRNA with lentiviral vector can specifically block the capability of LC-CD133⁺ to form spheres and can further facilitate LC-CD133⁺ to differentiate into LC-CD133⁻. In addition, knock-down of Oct-4 expression in LC-CD133⁺ can significantly inhibit the abilities of tumor invasion and colony formation, and increase apoptotic activities of caspase 3 and poly (ADP-ribose) polymerase (PARP). Finally, in vitro and in vivo studies further confirm that the treatment effect of chemoradiotherapy for LC-CD133⁺ can be improved by the treatment of Oct-4 siRNA. In conclusion, we demonstrated that Oct-4 expression plays a crucial role in maintaining the self-renewing, cancer stem-like, and chemoradioresistant properties of LC-CD133⁺. Future research is warranted regarding the up-regulated expression of Oct-4 in LC-CD133⁺ and malignant lung cancer.

Induction chemotherapy followed by concurrent chemoradiation for patients with non-operable stage III non-small-cell lung cancer

Combined modality treatment with chemotherapy (CT) and radiotherapy (RT) in stage III non-small-cell lung cancer is considered as standard therapy. As concomitant CT appears to be beneficial, the choice of anticancer agents and the role of induction chemotherapy is still unresolved. We present our experience based on an induction CT scheme with carboplatin plus paclitaxel followed by RT and concomitant CT. 31 patients with non-operable stage IIIA or IIIB NSCLC without pleural effusion were included in this study: 30 males, 1 female; median age 66 years (range: 50-81); 32% with non-operable stage IIIA and 68% with stage IIIB without pleural effusion; 61% squamous cell carcinoma, 32% adenocarcinoma and 7% other histologies. Regarding performance status (PS), 9.7% PS 0 and 90% PS 1 were included. Patients received 3 courses of induction CT with carboplatin AUC=6 and paclitaxel 175 mg/m(2), administrated i.v. on day 1 of each 21-day cycle, followed by thoracic irradiation (total dose 60-65 Gy, daily fractions 1.8-2 Gy) with two concurrent courses of carboplatin/paclitaxel. 16.2% of the patients achieved complete response, 48.4% partial response, 25.8% stable disease and 9.6% progression of disease. Median progression-free and overall survival was 12 and 18 months, respectively. The most frequent haematological toxicities were grade (G) 3 anaemia in 19.3%, G3 neutropenia in 9.6% and G4 neutropenia in 12.9%. Esophageal G2 toxicity (RTOG) was observed in 28.1% of cases. The induction CT followed by concomitant chemoradiation used in this study appears feasible, safe and effective when administered to an unselected inoperable NSCLC stage III patient cohort in the everyday routine clinical practice. Further, our results are comparable to previously published phase III studies.