CdSe/ZnS quantum dots induce photodynamic effects and cytotoxicity in pancreatic cancer cells.
OBJECTIVE
To investigate the photodynamic effect of CdSe/ZnS quantum dots (QDs) on pancreatic cancer cells and elucidate the probable mechanisms.


METHODS
The pancreatic cancer cell line SW1990 was treated with different concentrations of CdSe/ZnS QDs (0, 0.5, 1.0, 1.5, 2.0, 2.5 μmol/L), with or without illumination. The viability of SW1990 cells was tested using the Cell Counting Kit-8 (CCK-8) assay. The ultrastructural changes of SW1990 cells were observed by transmission electron microscopy. Apoptosis was detected by nuclear staining and flow cytometry (FCM). Reactive oxygen species (ROS) were measured by dichlorofluorescein diacetate via fluorescence microscopy. Expression of Bax, Bcl-2 and caspase-3 was measured by real-time polymerase chain reaction (PCR) and protein immunoblotting 24 h after SW1990 cells were treated with CdSe/ZnS QDs and illuminated.


RESULTS
The CCK-8 assay results showed that both CdSe/ZnS QDs with and without illumination suppressed SW1990 cell proliferation. Cell viability was significantly lower when illuminated or with a longer incubation time and a higher light dose. CdSe/ZnS QDs with illumination caused ultrastructural changes in SW1990 cells, such as organelle degeneration and chromatin condensation and aggregation at the periphery of the nucleus. Fluorescence microscopy and FCM showed that CdSe/ZnS QDs (1.5 μmol/L) with illumination increased SW1990 cell apoptosis (53.2%) and ROS generation compared with no illumination. Real-time PCR showed that expression of Bax and caspase-3 was upregulated and Bcl-2 was downregulated. Immunoblotting results were consistent with real-time PCR results. Inhibition of ROS and apoptosis both attenuated QD-photodynamic-therapy-induced cell death.


CONCLUSIONS
CdSe/ZnS QDs can be used as a photosensitizer to inhibit SW1990 cell proliferation through ROS generation and apoptotic protein expression regulation.
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Si-Jia
SJ
He
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Jia
J
Cao
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Yong-Sheng
YS
Li
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Jia-Chun
JC
Yang
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Min
M
Zhou
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Chun-Ying
CY
Qu
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Yi
Y
Zhang
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Feng
F
Shen
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Ying
Y
Chen
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Ming-Ming
MM
Li
Si-Jia He, Jia Cao, Jia-Chun Yang, Min Zhou, Chun-Ying Qu, Yi Zhang, Feng Shen, Ying Chen, Ming-Ming Li, Lei-Ming Xu, Department of Gastroenterology, Xinhua Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200092, China.
Lei-Ming
LM
Xu
D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D019187:Cadmium Compounds / Q000494:pharmacology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D018384:Oxidative Stress / Q000187:drug effects; D010190:Pancreatic Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000494:pharmacology*; D045663:Quantum Dots; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D018036:Selenium Compounds / Q000494:pharmacology*; D013440:Sulfides / Q000494:pharmacology*; D013997:Time Factors; D017967:Zinc Compounds / Q000494:pharmacology*
D051017:Apoptosis Regulatory Proteins; D019187:Cadmium Compounds; D017319:Photosensitizing Agents; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D018036:Selenium Compounds; D013440:Sulfides; D017967:Zinc Compounds; C058667:cadmium selenide; C031238:zinc sulfide
Apoptosis; Pancreatic cancer; Photodynamic therapy; Quantum dots; Reactive oxygen species