Auswahl der wissenschaftlichen Literatur zum Thema „HPMA kopolymery“

Chemotherapy is still the most widely used anti-cancer treatment. The majority of chemotherapeutics inhibit proliferating cells generally, not selectively cancer cells. The side effects associated with chemotherapy can be partly limited by conjugating a cytotoxic drug with a polymer nanocarrier. Such binding facilitates solubility in aqueous solutions, reduces systemic toxicity; and passively targets the drug directly into the tumour through the enhanced permeability and retention (EPR) effect. This thesis focuses on testing polymer conjugates based on N-(2-hydroxypropyl)methacrylamide (HPMA) carrying cucurbitacin D (CuD), a naturally occurring compound with potential anti-cancer activity. The mechanism of action is not elucidated yet, but several studies have depicted the inhibitory effect on signal transducer and activator of transcription 3 (STAT3) transcription factor. A STAT3 signalling pathway is overexpressed in several cancer cell lines and is also involved in the differentiation of myeloid- derived suppressor cells (MDSCs). We examined the therapeutic effect of the HPMA copolymers based on CuD in combined therapy with other polymer chemotherapeutics. CuD conjugates have shown in vitro cytotoxic effect on several model cancer cell lines. The combination with conjugates carrying doxorubicin...

7 ABSTRACT In this study, we addressed the biological activity and pharmacological features of selected HPMA copolymer-based drug conjugates. We determined their cytostatic activity in vitro as well as toxicity in vivo and therapeutic effcicacy in mouse tumor models. Assessment of maximum tolerated dose (MTD) of two structurally different HPMA copolymer-based conjugates bearing doxorubicin (DOX) attached via pH-sensitive hydrazon bond (HPMA- DOXHYD ) showed that high molecular weight non-degradable star HPMA-DOXHYD conjugate possesses relatively low MTD ~22.5 mg DOX/kg, while linear HPMA-DOXHYD has MTD ~85 mg DOX/kg. Thus, MTD of linear conjugate is 3.7 times higher than that of the star conjugate. Subsequently, we reported that linear conjugate proved to be more efficient in case of treatment of solid tumor EL4 lymphoma and star conjugate to be superior in case of BCL1 leukemia treatment. We also compared biological activity of star and linear HPMA copolymer-based conjugates bearing docetaxel (DTX) attached via pH-sensitive hydrazon bond (HPMA-DTXHYD ). MTD of star conjugate (~160 mg DTX/kg) was proved to be 4 times higher than MTD od free DTX (40 mg/kg). We were not able to determine MTD of linear conjugate as it exceeded 200 mg DTX/kg (the highest soluble dose we were able to administer as a bolus)....

Multidrug resistance (MDR) is a common cause of failure in chemotherapy for malignant diseases. Cancer cells develop MDR most often via the up-regulation of P- glycoprotein (P-gp) expression. P-gp is an efflux pump with broad specificity belonging to ATP-binding cassette (ABC) transporters which decreases the intracellular concentration of various drugs. We designed polymeric conjugates based on an N-(2-hydroxypropyl)methacrylamide (HPMA) bearing a cytostatic drug and/or P-gp inhibitor and tested their cytostatic/cytotoxic activity in vitro and their therapeutic efficacy in vivo in MDR tumors. We demonstrated that HPMA copolymer conjugates bearing both the cytostatic drug (doxorubicin (Dox) or pirarubicin) and the P-gp inhibitor (derivative of reversin 121 (R121) or ritonavir) possess remarkable cytostatic and cytotoxic activity in MDR tumor cell lines in vitro and superior antitumor activity in vivo. Notably, the HPMA copolymer conjugate bearing both Dox and R121 showed significant antitumor activity in both P388/MDR and CT26 mouse tumor models and was capable to completely cure 6 out of 8 mice with established CT26 tumors. We explored the potential of micelle-forming HPMA copolymer-poly(propylene oxide) (PPO) diblock bearing Dox to overcome MDR in vitro and in vivo. The HPMA copolymer-PPO diblock...

Tumor diseases are severe problem worldwide with increasing number of patients suffering from various types of malignancies. Many of approved therapeutics cause serious side toxicities. Therefore, there are intensive efforts to improve cancer treatment protocols. The aim of this study was to deplete regulatory T (Treg) cells without affecting other immunocompetent cells playing a positive role in tumor eradication. Treg cells were reported to hamper anti-tumor immunity and promote tumor growth and survival. Thus, their selective elimination could lead to induction of anti-tumor responses and tumor rejection if combined with chemotherapy with selected N-(2- hydroxypropyl)methacrylamide (HPMA) copolymer-bound drug conjugates. Original approach was to deplete of Treg cells without the use of anti-CD25 mAb that has been widely exploited for Treg cell elimination; however, its long-term persistence in circulation together with inhibitory effect on activated effector cells (CD25+ ) are its main disadvantages. Thus, Treg cells were sensitized to cell cycle-specific cytostatic drugs via application of IL-2/anti-IL-2 JES6.1 mAb immunocomplexes that induce vigorous selective proliferation of this cell population. Subsequent application of cell cycle-specific cytostatics showed steep decrease of Treg cell...

2. Summary of the PhD. Thesis Introduction The use of synthetic polymer carriers of anticancer drugs represents a promising approach to cancer therapy. Conjugation of cýotoxic drugs with polymers may reduce their toxicity and immunogenicity, eliminate undesirable body interactions, improve their solubility, bioavailability and stability (enzymatic. thermal, etc.), and prolong blood clearance' Moreover, polStmer drug carriers may enable specific delivery to the diseased tissue and controlled drug release in therapeutically active form. Since the first papers were published in the late 1970's the concept of polymer drug carrier systems has been generally accepted. In principle basic water-soluble poll,tner drug delivery systems consist of three parts: of polymer carrier, biodegradable spacer and drug. Preferably, drugs are covalently bound to the pol}mers via spacers, which enable controlled release of active drug in the target tissue or cells. Probably, most of the studied polymer carriers of cancerostatic drugs have been designed as lysosomotropic systems, where the drug could be released by enzymes rn lysosomes of tumour cells. In recent years pH-triggered hydrolytic drug release has been intensively studied. Here, the presence of enzynes is not essential, as the drug might be released in endosomes in...

Cancer remains one of the most pressing issues of contemporary science and medicine. Incidence of malignant diseases is rising worldwide and they represent a major problem for the society due to both economic and ethical issues they cause. Although the progress in cancer biology, therapy and immunology has led to the introduction of many novel therapeutic protocols, approaches and drugs with specificity defined on a molecular level into clinical practice, many malignancies retain their poor prognosis. Therefore, intense research into new ways to increase our therapeutic options is warranted. Unfortunately, bringing a completely novel drug into clinical use takes extremely high amounts of time and money and entails a high risk of failure. Therefore, a promising approach has been recently adopted which lies in repurposing compounds already used in human medicine for cancer treatment. This form of research can advance through clinical trials for a new indication much easier, faster and cheaper than researching completely new drugs. The aim of this study was to examine the anticancer potential of one such drug, mebendazole. An anthelminthic from the family of benzimidazoles, mebendazole has been in common clinical use from the 1970s and is marked by its low toxicity as well as its very low solubility....