Endomorphins, endogenous opioid peptides, induce apoptosis in human leukemia HL-60 cells

Abstract

Opioids play a role in the apoptosis machinery. We studied the induction of apoptosis in endomorphin 1 (EM1) and endomorphin 2 (EM2), 2 newly isolated endogenous mu-opioid receptor agonists. These endomorphins were able to reduce the viability of cultured HL-60 cells. The antiproliferative properties of endomorphins appeared to be attributable to their induction of apoptotic cell death as determined by ultrastructural change, internucleosomal DNA fragmentation, and increased proportion of the subdiploid cell population. To elucidate molecular events in the apoptosis, protein expressions of Bcl-2, Bax, Fas, and FasL were measured by western blotting using specific antibodies in HL-60 cells. The level of Bcl-2 indicated down-regulation, but the Bax, Fas, and FasL expression showed up-regulation as compared with the untreated control cells. These data support the idea that endomorphins induce apoptosis in HL-60 cells through the activation of the Bcl-2-Bax and the Fas-FasL pathway. We suggest that endomorphins may play an important role in the regulation of tumor cell death.

Opioid-regulated pro- and anti-apoptotic gene expression in cancer cells

“…Results are often contradictory and significant differences often occur between cell lines. For example endomorphins, endogenous MOR A C B agonists, were found to induce apoptosis in human leukemia HL-60 cells [15], but show no effect on cell survival in MIA PaCa-2 pancreatic adenocarcinoma, HT-29 colon adenocarcinoma, and CAL-27 oral adenosquamous carcinoma cell lines [16]. In our search for highly potent MOR-selective peptides as potential new analgesics, we have synthesized numerous analogs of MOR-selective agonists, endomorphin-2 and morphiceptin.…”

“…The concentration and purity of isolated RNA was determined using a spectrophotometer to examine absorbance at 260 and 280 nm. cDNA was synthesized using the Enhanced Avian HS RT-PCR Kit and oligo(dT) [12][13][14][15][16][17][18] primers (Sigma-Aldrich, St. Louis, MO, USA). Caspase-3, Bax, and Bcl-2 transcripts were quantified by real-time PCR using the Mx3005P QPCR System (Agilent Technologies, Inc. Santa Clara, CA, USA) according to the manufacturer's protocol for the Brilliant II SYBR Green QPCR Master Mix (Agilent Technologies, Inc. Santa Clara, CA, USA).…”

Impact of Opioid Use in Hematological Malignancies: Clinical, Immunological and Concomitant Aspects

“…Other data show the ways in which opioids affect the activity of apoptosis regulatory proteins in leukemia cells. Two recently described endogenous MOR agonists, endomorphine 1 and endomorphine 2, have been shown to reduce the viability of cultured HL-60 promyelocytic leukemia cells by inducing apoptosis through activation of the Bcl-2, Bax and Fas, FasL signaling pathways [ 92 ].…”

Endomorphins: structure, localization, immunoregulatory activity

“…В литературе есть данные об антипролиферативном эффекте эндоморфинов, поскольку они способны регулировать интенсивность пролиферации через усиление апоптотических процессов. Показано, что ЭМ-1 и ЭМ-2 понижали экспрессию Bcl-2 протеина и усиливали экспрессию Bax, Fas и FasL в клетках опухолевой линии REVIEW Проблемы эндокринологии / Problems of Endocrinology | 81 HL-60, таким образом индуцируя апоптоз в клетках HL-60 за счет активации Bcl-2-Bax и Fas-FasL-пути [42]. В то же время хронический воспалительный процесс в мочевом пузыре, индуцированный зимозаном, способствует снижению концентрации ЭМ-2 в грудном и поясничном отделах спинного мозга [43].…”