Long-term Smoking Mediated Down-regulation of Smad3 Induces Resistance to Carboplatin in Non-Small Cell Lung Cancer
While numerous cell signaling pathways are known to play decisive roles in chemotherapeutic response, relatively little is known about the impact of the Smad-dependent transforming growth factor β pathway on the therapeutic outcome. Previous reports suggested that patients with lung cancer who conti...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2012-07-01
|
| Series: | Neoplasia: An International Journal for Oncology Research |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S1476558612800984 |
| _version_ | 1819043129863438336 |
|---|---|
| author | Debangshu Samanta Jacob Kaufman David P. Carbone Pran K. Datta |
| author_facet | Debangshu Samanta Jacob Kaufman David P. Carbone Pran K. Datta |
| author_sort | Debangshu Samanta |
| collection | DOAJ |
| description | While numerous cell signaling pathways are known to play decisive roles in chemotherapeutic response, relatively little is known about the impact of the Smad-dependent transforming growth factor β pathway on the therapeutic outcome. Previous reports suggested that patients with lung cancer who continue to smoke while receiving chemotherapy have a poorer outcome than their nonsmoking counterparts do. In our previous study, we showed that long-term cigarette smoke condensate (CSC)-mediated down-regulation of Smad3 induces tumorigenesis. The objective of this study was to determine the mechanism of function of Smad3 in chemoresistance induced by CSC in human lung cell lines, namely, A549 and HPL1A. Long-term CSC treatment increases the half-maximal inhibitory concentration (IC50) of carboplatin and makes cells resistant to carboplatin. The increase in IC50 of long-term CSC-treated cells is due to the reduced induction in apoptosis by carboplatin. The increase in IC50 and decrease in apoptosis in long-term CSC-treated cells is correlated with the expression of Bcl2. We have determined that Bcl2 is both necessary and sufficient to make the cells resistant to carboplatin. We have also shown that Smad3 acts upstream to regulate the expression of Bcl2 specifically and, thus, sensitivity of the cells to carboplatin. This is supported by the inverse correlation between the expressions of Smad3 and Bcl2 in human lung tumors. Collectively, these data suggest that loss of Smad3 expression in CSC-treated cells induces resistance to carboplatin by upregulating the expression of Bcl2. This study explains, at least in part, the higher chemoresistance rate observed in smokers. |
| first_indexed | 2024-12-21T09:51:53Z |
| format | Article |
| id | doaj.art-f5e71615bb174fcbb45984b43f4e5f9d |
| institution | Directory Open Access Journal |
| issn | 1476-5586 1522-8002 |
| language | English |
| last_indexed | 2024-12-21T09:51:53Z |
| publishDate | 2012-07-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Neoplasia: An International Journal for Oncology Research |
| spelling | doaj.art-f5e71615bb174fcbb45984b43f4e5f9d2022-12-21T19:08:10ZengElsevierNeoplasia: An International Journal for Oncology Research1476-55861522-80022012-07-0114764465510.1593/neo.12548Long-term Smoking Mediated Down-regulation of Smad3 Induces Resistance to Carboplatin in Non-Small Cell Lung CancerDebangshu Samanta0Jacob Kaufman1David P. Carbone2Pran K. Datta3Department of Surgery, Vanderbilt University School of Medicine, Nashville, TNDepartment of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TNDepartment of Medicine, Vanderbilt University School of Medicine, Nashville, TNDepartment of Surgery, Vanderbilt University School of Medicine, Nashville, TNWhile numerous cell signaling pathways are known to play decisive roles in chemotherapeutic response, relatively little is known about the impact of the Smad-dependent transforming growth factor β pathway on the therapeutic outcome. Previous reports suggested that patients with lung cancer who continue to smoke while receiving chemotherapy have a poorer outcome than their nonsmoking counterparts do. In our previous study, we showed that long-term cigarette smoke condensate (CSC)-mediated down-regulation of Smad3 induces tumorigenesis. The objective of this study was to determine the mechanism of function of Smad3 in chemoresistance induced by CSC in human lung cell lines, namely, A549 and HPL1A. Long-term CSC treatment increases the half-maximal inhibitory concentration (IC50) of carboplatin and makes cells resistant to carboplatin. The increase in IC50 of long-term CSC-treated cells is due to the reduced induction in apoptosis by carboplatin. The increase in IC50 and decrease in apoptosis in long-term CSC-treated cells is correlated with the expression of Bcl2. We have determined that Bcl2 is both necessary and sufficient to make the cells resistant to carboplatin. We have also shown that Smad3 acts upstream to regulate the expression of Bcl2 specifically and, thus, sensitivity of the cells to carboplatin. This is supported by the inverse correlation between the expressions of Smad3 and Bcl2 in human lung tumors. Collectively, these data suggest that loss of Smad3 expression in CSC-treated cells induces resistance to carboplatin by upregulating the expression of Bcl2. This study explains, at least in part, the higher chemoresistance rate observed in smokers.http://www.sciencedirect.com/science/article/pii/S1476558612800984 |
| spellingShingle | Debangshu Samanta Jacob Kaufman David P. Carbone Pran K. Datta Long-term Smoking Mediated Down-regulation of Smad3 Induces Resistance to Carboplatin in Non-Small Cell Lung Cancer Neoplasia: An International Journal for Oncology Research |
| title | Long-term Smoking Mediated Down-regulation of Smad3 Induces Resistance to Carboplatin in Non-Small Cell Lung Cancer |
| title_full | Long-term Smoking Mediated Down-regulation of Smad3 Induces Resistance to Carboplatin in Non-Small Cell Lung Cancer |
| title_fullStr | Long-term Smoking Mediated Down-regulation of Smad3 Induces Resistance to Carboplatin in Non-Small Cell Lung Cancer |
| title_full_unstemmed | Long-term Smoking Mediated Down-regulation of Smad3 Induces Resistance to Carboplatin in Non-Small Cell Lung Cancer |
| title_short | Long-term Smoking Mediated Down-regulation of Smad3 Induces Resistance to Carboplatin in Non-Small Cell Lung Cancer |
| title_sort | long term smoking mediated down regulation of smad3 induces resistance to carboplatin in non small cell lung cancer |
| url | http://www.sciencedirect.com/science/article/pii/S1476558612800984 |
| work_keys_str_mv | AT debangshusamanta longtermsmokingmediateddownregulationofsmad3inducesresistancetocarboplatininnonsmallcelllungcancer AT jacobkaufman longtermsmokingmediateddownregulationofsmad3inducesresistancetocarboplatininnonsmallcelllungcancer AT davidpcarbone longtermsmokingmediateddownregulationofsmad3inducesresistancetocarboplatininnonsmallcelllungcancer AT prankdatta longtermsmokingmediateddownregulationofsmad3inducesresistancetocarboplatininnonsmallcelllungcancer |