Serum cytochrome c indicates in vivo apoptosis and can serve as a prognostic marker during cancer therapy.
Despite significant progress in cancer therapy, the outcome of the treatment is often unfavorable. Better treatment monitoring would not only allow an individual more effective, patient-adjusted therapy, but also it would eliminate some of the side effects. Using a cytochrome c ELISA that was modified to increase sensitivity, we demonstrate that serum cytochrome c is a sensitive apoptotic marker in vivo reflecting therapy-induced cell death burden. Furthermore, increased serum cytochrome c level is a negative prognostic marker. Cancer patients whose serum cytochrome c level was normal 3 years ago have a twice as high probability to be still alive, as judged from sera samples collected for 3 years, analyzed recently and matched with survival data. Moreover, we show that serum cytochrome c and serum LDH-activity reflect different stages and different forms of cell death. Cellular cytochrome c release is specific for apoptosis, whereas increased LDH activity is an indicator of (secondary) necrosis. Whereas serum LDH activity reflects the "global" degree of cell death over a period of time, the sensitive cytochrome c-based method allows confirmation of the individual cancer therapy-induced and spontaneous cell death events. The combination of cytochrome c with tissue-specific markers may provide the foundation for precise monitoring of apoptosis in vivo, by "lab-on-the-chip" technology.
Barczyk
Katarzyna
K
Department of Immunology, Faculty of Biotechnology, Jagiellonian University, Krakow, Poland.
Kreuter
Michael
M
Pryjma
Juliusz
J
Booy
Evan P
EP
Maddika
Subbareddy
S
Ghavami
Saeid
S
Berdel
Wolfgang E
WE
Roth
Johannes
J
Los
Marek
M
D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000097:blood*; D045304:Cytochromes c / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D011379:Prognosis; D012680:Sensitivity and Specificity; D016019:Survival Analysis; D016896:Treatment Outcome
D014408:Biomarkers, Tumor; D045304:Cytochromes c