engleski

The effect of Met-enkephalin, thiorphan and naloxone on the expression of CD10 molecule and apoptosis in NALM-1 cells

NALM-1 cells are human, pre-B leukemic, which express CD10 molecule, what is also a neutral endopeptidase (NEP). An opiod pentapeptide Met-enkephalin has been described as the negative regulator of tumor growth in the literature. We have previously shown that Met-enkephalin, a natural substrate for NEP, thiorphan an inhibitor of NEP, and naloxone an antagonist of opioid receptors, moderately and transiently suppressed proliferation of NALM-1 cells after 6 hours treatment (MTT test). In this study the usibility of an endogenous opioid pentapetide Met-enkephalin to modulate membrane expression of CD10 molecule, and the ability to trigger apoptosis was tested. Thiorphan, the inhibitor of NEP activity served as the positive control, and naloxone, an antagonist of opioid receptors, as the negative control. FACS analysis indicated moderate decrease of CD10 expression after 24 hours treatment with Met-enekphalin (10-6M) and Thiorphan (5x10-5M). Naloxone did not affect CD10 expression. DNA was not fragmented after 6 and 24 hours of treatment of NALM-1 cells with Met-enkephalin(10-6, 10-7, 10-8 M), naloxone (10-5, 10-6,10-7M) and thirophan (10-4, 5x10-5M). In our previous results we showed that Met-enkephalin moderately and transiently suppressed the growth of NALM-1 cells. This inhibition did not include apoptosis, since no DNA fragmentation was detected. The membrane expression of CD10 molecule was moderately decreased by Met-enkephalin (natural substrate for NEP) and thiorphan (NEP enzyme), while naloxone (an opioid receptor antagonsit) was not effective. These results indicate the regulatory role of CD10 molecule.

Met-enkephalin; thiorpohan; naloxone; CD10; NALM-1 cells

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