Uloga purinskog nukleozidnog analoga-sulfinozina u inhibiciji rasta malignih ćelija neosetljivih na dejstvo hemioterapeutika
The role of purine nucleoside analog - sulfinosine in growth inhibition of cancer cells resistant to classic chemotherapeutics
Author
Dačević, Mirjana P.Mentor
Isaković, Aleksandra
Committee members
Pešić, Milica
Marković, Ivanka

Rakić, Miodrag
Ruždijić, Sabera

Metadata
Show full item recordAbstract
Efikasno izlečenje tumora je veoma teško postići posebno kada se razvije višestruka
rezistencija (MDR) na konvencionalnu antineoplastičnu terapiju. Visoka aktivnost Pglikoproteina
(P‐gp) je ključni mehanizam razvoja MDR kod različitih tipova karcinoma.
Upravo je pronalaženje antitumorskog agensa koji bi istovremeno ubijao ćelije tumora i
inhibirao MDR veoma važan korak u razvoju novih terapijskih strategija za lečenje malignih
oboljenja. U našem radu smo se bavili istraživanjem efekata koje sulfinozin (SF) ispoljava
na dve ćelijske linije sa uspostavljenom MDR fenotipom kod kojih je P‐gp pumpa
prekomerno eksprimirana (nesitnoćelijski karcinom pluća tj. NCI‐H460/R i glioblastom tj.
U87‐TxR). SF je uzrokovao sličan citotoksičan efekat kod senzitivnih (NCI‐H460 i U87) i
rezistentnih (NCI‐H460/R i U87‐TxR) ćelijskih linja, dok kod normalnih ćelija (HaCaT)
citotoksičnost nije uočena ni pri tretmanu sa visokim dozama (100 μM). SF kod
rezistentnih ćelija dovodi do indukcije apoptoze, što je p...otvrđeno i aktivacijom efektorske
kaspaze 3. Apotoza zavisna od kaspaza je praćena pojavom autofagije. Nakon dejstva SF‐a
dolazi do povećanja sadržaja kiseoničnih reaktivnih vrsta i smanjenja koncentracije
glutationa (GSH). SF svojim delovanjem dovodi i do smanjenja ekspresije ključnog enzima
glutationskog sistema γGCS i ekspresije gst‐π iRNK. Posledično, SF dovodi do značajnog
smanjenja ekspresije iRNK gena koji su odgovorni za tumorsku progresiju: hif‐1α, mdr1 i
vegf i u hipoksičnim uslovima. SF takođe dovodi do inhibicije ekspresije i aktvinosti P‐gp‐a.
Pokazano je da SF kod rezistentnih ćelija dovodi do povećanja akumulacije standardnog
hemioterapeutika doksorubicina (DOX). Svoj najbolji efekat SF ispoljava nakon 72 h i ovaj
efekat je sličan efektu koji postižu tarikvidar i Dex‐verapamil. Može se zaključiti da SF
dovodi do senzitizacije rezistentnih ćelijskih linija na DOX u naizmeničnom tretmanu. Uz
to, SF dovodi do smanjenja ekspresije iRNK vaskularnog endotelijalnog faktora rasta
(VEGF) i utiče na modulaciju njegove sekrecije. Na osnovu svega navedenog zaključujemo
da se SF može klasifikovati kao multi‐potentni antikancerski agent posebno za primenu
kod rezistentnih maligniteta.
Achieving an effective treatment of cancer is difficult, particularly when resistance to
conventional chemotherapy is developed. P‐glycoprotein (P‐gp) activity governs multidrug
resistance (MDR) development in different cancer cell types. Identification of anticancer
agents with the potential to kill cancer cells and at the same time inhibit MDR is
important to intensify the search for novel therapeutic approaches. We examined the
effects of sulfinosine (SF), a quite unexplored purine nucleoside analog, in MDR (P‐gp
over‐expressing) non‐small cell lung carcinoma (NSCLC) and glioblastoma cell lines (NCIH460/
R and U87‐TxR, respectively). SF showed the same efficacy against MDR cancer cell
lines and their sensitive counterparts. However, it was non‐toxic for normal human
keratinocytes (HaCaT). SF induced caspase‐dependent apoptotic cell death and autophagy
in MDR cancer cells. After SF application, reactive oxygen species (ROS) were generated
and glutathione (GSH) concentration was decre...ased. The expression of key enzyme for
GSH synthesis, gamma Glutamyl‐cysteine‐synthetase (γGCS) was decreased as well as the
expression of gst‐π mRNA. Consequently, SF significantly decreased the expression of hif‐
1α, mdr1 and vegf mRNAs even in hypoxic conditions. SF caused the inhibition of P‐gp
(coded by mdr1) expression and activity. The accumulation of standard chemotherapeutic
agent – doxorubicin (DOX) was induced by SF in concentration‐ and time‐dependent
manner. The best effect of SF was obtained after 72 h when it attained the effect of
known P‐gp inhibitors (Dex‐verapamil and tariquidar). Accordingly, SF sensitized the
resistant cancer cells to DOX in subsequent treatment. Furthermore, SF decreased the
experssion of vascular endothelial growth factor (VEGF) on mRNA and protein level and
modulated its secretion. In conclusion, the effects on P‐gp (implicated in pharmacokinetics
and MDR), GSH (implicated in detoxification) and VEGF (implicated in tumor‐angiogenesis
and progression) qualify SF as multi‐potent anti‐cancer agent, which use must be
considered, in particular for resistant malignancies.
Faculty:
Универзитет у Београду, Медицински факултетDate:
14-10-2013Projects:
- Modulation of intracellular energy balance-controlling signalling pathways in therapy of cancer and neuro-immuno-endocrine disorders (RS-41025)
- Identification of predictive molecular markers for cancer progression, response to therapy and disease outcome (RS-41031)