A systematic study was designed to elucidate differences in cytostatic activity in vitro between HPMA-based doxorubicin conjugates synthesized using different polymerization techniques and differing in peptidyl side chain. A polymer-drug conjugate containing doxorubicin (DOX) bound to HPMA copolymer backbone through the enzymaticaly non-cleavable sequence GlyGly shows low but significant cytotoxicity in vitro in seven cancer cell lines of mouse (EL4, 38C13, 3T3, BCL1) and human (SW620, Raji, Jurkat) origin. The low cytotoxicity can be considerably increased by the presence of additional drug-free GlyPheLeuGly side chains. P1 conjugate, i.e. non-targeted HPMA copolymer bearing doxorubicin bound via a biodegradable GlyPheLeuGly sequence, synthesized by direct copolymerization of HPMA with monomeric doxorubicin and thus without additional drug-free GlyPheLeuGly sequences is less effective compared to PK1 synthesized by polymer analogous reaction and thus containing extra drug-free GlyPheLeuGly sequences. Significant activity-enhancing effect was not seen with other amino acid/oligopeptide sequences (e.g., Gly or GlyGly). The activity-enhancing effect of GlyPheLeuGly sequences is more obvious in the conjugate containing doxorubicin bound to HPMA through GlyGly sequence. Derivatization of the terminal carboxyl group of the extra GlyPheLeuGly side chains (amide, N-substituted amide, free carboxyl) does not significantly influence the cytotoxicity of the conjugates. The presence of the GlyPheLeuGly sequence in the conjugate structure increases its rate of intracellular accumulation. Normal cells (Balb/c splenocytes) accumulate less polymer-doxorubicin conjugate compared to cancer cells (T cell lymphoma EL4, B cell lymphoma Raji and T cell leukemia JURKAT).
- MeSH
- antibiotika antitumorózní farmakologie MeSH
- apoptóza MeSH
- doxorubicin farmakologie MeSH
- financování organizované MeSH
- kultivované buňky MeSH
- kyseliny polymethakrylové farmakologie MeSH
- lidé MeSH
- methakryláty chemie MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- nekróza MeSH
- oligopeptidy farmakologie chemie MeSH
- proliferace buněk účinky léků MeSH
- slezina cytologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
Linkage of doxorubicin (Dox) to a water-soluble synthetic N-(2-hydroxypropyl)methacrylamide copolymer (PHPMA) eliminates most of the systemic toxicity of the free drug. In EL-4 lymphoma-bearing C57BL/6 mice, a complete regression of pre-established tumours has been achieved upon treatment with Dox-PHPMA-HuIg conjugate. The treatment was effective using a range of regimens and dosages, ranging from 62.5 to 100% cured mice treated with a single dose of 10-20 mg of Dox eq./kg, respectively. Fractionated dosages producing lower levels of the conjugate for a prolonged time period had substantial curative capacity as well. The cured mice developed anti-tumour protection as they rejected subsequently re-transplanted original tumour. The proportion of tumour-protected mice inversely reflected the effectiveness of the primary treatment. The treatment protocol leading to 50% of cured mice produced only protected mice, while no mice treated with early treatment regimen (i.e. starting on day 1 after tumour transplantation) rejected the re-transplanted tumour. Exposure of the host to the cancer cells was a prerequisite for developing protection. The anti-tumour memory was long lasting and specific against the original tumour, as the cured mice did not reject another syngeneic tumour, melanoma B16-F10. The immunity was transferable to naive recipients in in vivo neutralization assay by spleen cells or CD8(+) lymphocytes derived from cured animals. We propose an effective treatment strategy which eradicates tumours without harming the protective immune anti-cancer responses.
- MeSH
- antibiotika antitumorózní terapeutické užití MeSH
- doxorubicin analogy a deriváty terapeutické užití MeSH
- financování organizované MeSH
- imunoglobuliny terapeutické užití MeSH
- imunologická tolerance MeSH
- kyseliny polymethakrylové terapeutické užití MeSH
- lidé MeSH
- lymfom T-buněčný farmakoterapie imunologie prevence a kontrola MeSH
- melanom experimentální farmakoterapie imunologie metabolismus MeSH
- míra přežití MeSH
- myši inbrední C57BL MeSH
- myši nahé MeSH
- myši MeSH
- nádorové buňky kultivované transplantace MeSH
- nádory kůže farmakoterapie imunologie metabolismus MeSH
- nosiče léků MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- myši MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- abstrakt z konference MeSH
