[Background] Cordyceps militaris is a traditional popular mushroom, produces an important bioactive compound Cordycepin (3’-deoxyadenosine) used for the tonic and medicinal purpose in eastern Asia. Cordycepin is reported to possess many pharmacological activities including immunologically stimulating, anti-tumor, anti-virus, and anti-infection effects. [Methods] Growth inhibition of human leukemia cells was assessed by MTT assays. The determination of apoptotic cell death was performed by flow cytometry analysis, agarose gel electrophoresis and DAPI fluorescent staining methods. The apoptotic-regulated gene markers in both death receptor- and mitochondria-mediated apoptotic pathways were detected by RT-PCR and Western blot analysis etc. [Results] It was found that inhibition of cell proliferation was observed for human leukemia U937 and THP-1 cells treated with cordycepin in a dose-dependent manner. Cordycepin induced morphological change and apoptotic cell death such as formation of apoptotic bodies, DNA fragmentation and increased populations of apoptotic-sub G1 phase. Apoptosis of U937 and THP-1 cells by cordycepin was associated with a down-regulation of anti-apoptotic Bcl-2 and inhibitor of apoptosis proteins (IAPs) expression. Cordycepin treatment induced the proteolytic activation of caspase-3, caspase-8 and caspase-9, and a concomitant inhibition of poly(ADP-ribose) polymerase (PARP), β-catenin and phospholipase (PLC)-γ1 protein. Conclusions: Our results indicated that the apoptotic processes caused by cordycepin are mediated by the regulation of the Bcl-2 and caspase family in human leukemia U937 and THP-1 cells. Our data also suggested that cordycepin may be a potential chemotherapeutic agent for the treatment of leukemia cancer patients.

Cordycepin (3’-deoxyadenosin), a polyadenylation specific inhibitor, is the main functional component in Cordyceps militaris which is one of the top three famous traditional Chinese medicine. It has been shown to possess many pharmacological activities including immunologically stimulating, anti-cancer, anti-bacterial, and anti-virus, anti-infection effects. However, its anti-cancer molecular mechanisms are poorly understood. In this study, the apoptotic effects by cordycepin were investigates in human leukemia cells. Treatment of cordycepin significantly inhibited cells growth in a concentrationdependent manner by inducing apoptosis, as evidenced by morphological change and apoptotic cell death such as formation of apoptotic bodies, DNA fragmentation and increased populations of sub-G1. Induction of apoptosis by cordycepin was associated with modulation of Bcl-2 and inhibitor of apoptosis proteins (IAP) family expression. Cordycepin also increased reactive oxygen species (ROS) generation, activation of casepase-3, caspase-8, caspase-9, cleavage of poly(ADP-ribose) polymerase (PARP), β-catenin and phospholipase C (PLC)-γ1 protein. The quenching of ROS generation by N-acetyl-L-cysteine administration, a scavenger of ROS, reversed the cordycepin-induced apoptosis effects. Theresults suggested that cordycepin may be a potential chemotherapeutic agent for the treatment of leukemia patients [This work was supported by Blue-Bio Industry RIC at Dong-Eui University as a RIC (08-06-07) program of ITEP under Ministry of Knowledge Economy].

Cordycepin (3’-deoxyadenosine) is a polyadenylation specific inhibitor, one of the components of Cordyceps militaris. It has been shown to possess many pharmacological activities including immunologically stimulating, anti-tumor, anti-virus, and anti-infection effects. However, its molecular mechanisms are poorly understood. In this study, the apoptotic effects by cordycepin were investigated in human leukemia cells. Cordycepin treatment inhibited leukemia cells growth a concentration-dependent manner by inducing apoptosis,as evidenced by morphological change and apoptotic cell death such as formation of apoptotic bodies, DNA fragmentation and increased populations of apoptoticsub G1 phase. Induction of apoptosis by cordycepin in leukemia cells were associated with modulation of Bcl-2 member and inhibitor of apoptosis (IAP) proteins expression. Cordycepin also increased ROS generation, activation of caspase-3, caspase-8, caspase-9, cleavage of poly(ADP-ribose) polymerase (PARP), -catenin and phospholipase (PLC)-1 protein. Both the this effect by cordycepin treatment were significantly inhibited by NAC, a ROS scavenger, demonstrating the important role of ROS in the observed cytotoxic effect. This results suggested that cordycepin may be a potential chemotherapeutic agent for the treatment of leukemia patients.

The differentiation of leukemia cells into mature cells is a major target of the human leukemia therapy. As differentiated leukemia cells lose their proliferative and tumor-forming abilities, differentiation inducers may be useful for the treatment of leukemia. In this study, the experiments were designed to determine whether diallyl disulfide (DADS) regulates expressions of tumor suppressor protein PTEN (phosphatase and tension homologue) in HL- 60 cells. DADS causes upregulation of PTEN in a time- and dose-dependent manner, which was correlated with decrease of phospho-Akt level. These results suggest that DADS induces upregulation of PTEN in human leukemia cells. These results suggest that DADS may be a useful anticancer agent for management of human leukemia.

In order to study the antitumoral effect of Selaginella tamariscina extracts, the cytotoxicities to human histiocytic leukemia cells (U937) and lymphocyte were measured by MTT method. The water extract of Selaginella tamariscina was partitioned into chloroform (CHCl₃), ethylacetate (EtAc), n-butanol (BuOH) and water (H₂O), successively. CHCl₃, EtAc and BuOH fractions of Selaginella tamariscina showed the cytotoxicity to the U937 cells but they had no effect on the cytotoxicity of lymphocyte under the same conditions. The tumor-specific cytotoxicity of Selaginella tamariscina fractions might have been attributed to their genotoxic effect on actively proliferating cells. The expression of p53 tumor suppressor gene was then evaluated by northern blotting. The increased expression of p53 was induced by Selaginella ramariscina fraction V but no expression of p53 was induced by CHCl₃, EtAc, and BuOH fractions of Selaginella tamariscina. These results suggested that the increased expression of p53 induced by Selaginella tamariscina water extract (fraction V) should be required for the cytotoxicity on U937 and the other fractions of Selaginella tamariscina mediated the U937 disruption.

본 연구에서는 부처꽃 에탄올 추출물(ELM)에 대한 항암효능을 알아보기 위하여 인체백혈병 U937 세포의 증식에 미치는 영향과 이와 연관된 apoptosis 유발 여부와 함께 그에 따른 분자생물학적 기전에 대해서 조사하였다. 먼저 ELM 처리에 따른 증식 억제 정도를 조사한 결과, ELM 처리 농도 의존적으로 생존율 및 증식억제 현상이 나타났으며, 핵의 형태 변화, DNA 단편화 및 apoptosis 유발에 관하여 조사한 결과 역시 ELM 처리 농도 의존적으로 증가됨을 확인할 수 있었다. ELM 처리에 따른 U937 세포에서의 apoptosis 유발에 있어서 미토콘드리아 막의 기능 손상이 관여하는 지를 확인하기 위하여 MMP의 변화 정도를 확인 한 결과, ELM 처리 농도 증가에 따라 MMP의 소실이 증가하는 것을 관찰할 수 있었다. 이러한 MMP의 소실에 가 관여하는지를 확인하기 위하여 사멸수용체(DR4, 5, Fas) 및 사멸수용체에 결합하는 리간드(FasL, TRAIL)의 발현 변화를 확인한 결과, DR4 및 DR5의 발현이 증가하는 것으로 관찰되었다. 또한 내인적 경로에 관여하는 Bcl-2 family 유전자들의 발현변화를 확인 한 결과, Bcl-2 발현 감소 및 Bax의 발현 증가의 변화를 보였으며, Bid 단백질의 발현감소가 나타났으므로 상대적으로 tBid의 생성이 증가되었음을 추측할 수 있었다. 한편 apoptosis 유발에 직접적으로 관여하는 것으로 알려진 caspase-3, -8 및 -9의 발 현에 미치는 ELM의 영향에 대해서 조사하였다. 결과에서 알 수 있듯이 ELM은 death receptor에 의하여 활성화 되는 것으로 알려진 caspase-8 및 세포질로 방출된 cytochrome c에 의하여 활성화 되는 것으로 알려진 caspase-9의 활성화를 유발하였으며, caspase cascade에 의하여 apoptosis에 직접적으로 관여하는 caspase-3의 발현도 증가시키는 것으로 나타났다. 또한 활성화된 caspase-3에 의하여 분해가 일어나는 기질 단백질인 PARP의 경우 ELM 처리에 의하여 모두 단편화가 유발되는 것으로 나타났다. 이상의 결과를 종합해 보면 인체 백혈병 U937 세포에 ELM을 처리하였을 경우에 유발되는 apoptosis는 외인적 경로인 DR4 및 DR5의 발현 증가를 통한 caspase-8의 활성화와 이로 인한 Bid 단백질의 단편화와 함께 내인적 경로의 미토콘드리아 기능 손실에 의하여 caspase-9 및 -3의 활성화 유발과 기질단백질들의 분해가 중요한 역할을 하는 것으로 생각되며, IAP family의 발현 감소로 인하여 caspase의 활성이 억제되지 못하는 것도 apoptosis 유도에 어느 정도 관여했을 것으로 생각 된다. 따라서 ELM 처리에 의하여 유발되는 apoptosis는 외인적 경로 및 내인적 경로를 모두 경유하는 multiple apoptotic pathway에 의하여 조절되며, 이때 caspases가 중요한 역할을 한다는 것을 알 수 있었다.

일상생활에서 식용 또는 약용으로 이용되고 있는 12종의 버섯 추출물을 제조하여 이들 추출물의 항산화능 검색과 함께 인간유래의 혈액암 세포주 및 정상 임파구세포의 성장에 미치는 영향에 대하여 조사하였다. 그 결과, 향버섯, 번데기동충하초, 만가닥버섯, 아가리쿠스, 영지버섯, 표고버섯 메탄올 추출물에서 정도의 DPPH radical 소거 활성을 보였고, 목이버섯, 그물버섯, 새송이버섯에서 의 활성을 보였다. 또한 chinese hamster V79