Effects of hypoxia on tumor metabolism

Cechą charakterystyczną guzów litych jest ich niedotlenienie, które istotnie wpływa na biologię nowotworu orazodpowiedź na standardowe schematy leczenia (chemioterapię i radioterapię), co w konsekwencji decyduje o stopniuzaawansowania choroby nowotworowej pacjentów. Odpowiedź adaptacyjna komórek nowotworowych do warunkówhipoksji jest związana ze stymulacją angiogenezy i erytropoezy oraz zmianą metabolizmu komórek guza. W komórkachnowotworowych następuje przestrojenie metabolizmu, które prowadzi do wzrostu glikolizy, zahamowania fosforylacjioksydacyjnej i zwiększenia syntezy kwasów tłuszczowych de novo. Niedotlenienie powoduje aktywację czynnikatranskrypcyjnego HIF-1, który odgrywa kluczową rolę w przeprogramowaniu metabolizmu komórek nowotworowychpoprzez aktywację transkrypcji genów kodujących transportery glukozy i enzymy glikolityczne, co umożliwia zwiększenieglikolizy. Ponadto HIF-1 aktywuje kinazę dehydrogenazy pirogronianowej 1 (pyruvate dehydrogenase kinase1, PDK1), która powoduje zmniejszenie oddychania mitochondrialnego. Przesunięcie oksydacyjnego metabolizmuw stronę glikolizy beztlenowej pozwala na utrzymanie homeostazy redoks i umożliwia przeżycie oraz proliferacjękomórek nowotworowych w warunkach niedotlenienia.A major feature of solid tumors is hypoxia which affects cancer biology, increases resistance to treatment and patientprognosis. Adaptive responses of cells to hypoxia include stimulation of angiogenesis, erythropoiesis and alterationof cellular metabolism. Cancer cells are characterized by reprogramming of metabolism leading to increased glycolysis,attenuation of oxidative phosphorylation and de novo synthesis of fatty acids. Hypoxia-induced activation ofhypoxia-inducible factor (HIF-1) plays an important role in the reprogramming of cancer metabolism by activatingtranscription of genes encoding glucose transporters and glycolytic enzymes leading to increased glucose uptake,and pyruvate dehydrogenase kinase 1 (PDK1), which diminished mitochondrial respiration. The shift from oxidativeto glycolytic metabolism allows maintenance of redox homeostasis, survival and continued proliferation of cancercells under hypoxic conditions

Zastosowanie nanocząsteczek w leczeniu i diagnostyce nowotworów

Nanotechnologia jest nowym interdyscyplinarnym działem nauki, zajmującym się konstrukcją nanocząsteczek, i jejosiągniecia są wykorzystywane w farmacji i medycynie. Choroby nowotworowe są jedną z głównych przyczyń zgonówna świecie. Stosunkowo późne wykrycie zmian nowotworowych oraz mała skuteczność standardowych metodleczenia — ze względu na brak specyfi czności i dużą toksyczność — niekorzystnie wpływają na rokowanie pacjentów.Wykorzystanie nanocząsteczek w diagnostyce molekularnej umożliwia wczesne wykrycie guzów i tym samych rozpoczęciewcześniejszego leczenia. Nanocząsteczki mają również ogromne zastosowanie w terapii przeciwnowotworowejjako nośniki związków terapeutycznych, co powoduje wzrost ich biodostępności i akumulacji w obszarze guzówi zapewnia dostarczenie leków w efektywnych dawkach. Opłaszczenie nanocząsteczek specyfi cznymi ligandami lubprzeciwciałami umożliwia celowaną terapię, co nie tylko zwiększa skuteczność leczenia, ale także istotnie zmniejszacytotoksyczność na komórki prawidłowe. Na uwagę zasługują wielofunkcyjne nanoczasteczki, które są stosowanedo jednoczesnego wykrycia zmian nowotworowych i ich leczenia. Wykorzystanie nanocząsteczek w onkologii dajemożliwość wczesnej diagnozy, dostarczenia leków specyfi cznie do komórek nowotworowych w skutecznej dawceoraz monitorowanie postępów terapii

New Selective Progesterone Receptor Modulators and Their Impact on the RANK/RANKL Complex Activity

Breast cancer depends on women’s age. Its chemotherapy and hormone therapy lead to the loss of bone density and disruption of the skeleton. The proteins RANK and RANKL play a pivotal role in the formation of osteoclasts. It is also well established that the same proteins (RANK and RANKL) are the main molecules that play an important role in mammary stem cell biology. Mammary stem cells guarantee differentiation of the epithelial mammary cells, the growth of which is regulated by the progesterone-induced RANKL signaling pathway. The crosstalk between progesterone receptor, stimulated by progesterone and its analogues results in RANKL to RANK binding and activation of cell proliferation and subsequently unlimited expansion of the breast cancer cells. Therefore downstream regulation of this signaling pathway is desirable. To meet this need, a new class of selective estrogen receptor modulators (SPRMs) with anti- and mesoprogestin function were tested as potential anti-RANK agents. To establish the new feature of SPRMs, the impact of tested SPRMs on RANK-RANKL proteins interaction was tested. Furthermore, the cells proliferation upon RANKL stimulation, as well as NFkB and cyclin D1 expression, induced by tested SPRMs were analyzed. Conducted experiments proved NFkB expression inhibition as well as cyclin D1 expression limitation under asoprisnil and ulipristal treatment. The established paracrine anti-proliferative activity of antiprogestins together with competitive interaction with RANK make this class of compounds attractive for further study in order to deliver more evidence of their anti-RANK activity and potential application in the breast cancer therapy together with its accompanied osteoporosis

Antiproliferative Aspect of Benzimidazole Derivatives’ Activity and Their Impact on NF-κB Expression

Benzimidazoles belong to a new class of bioreductive agents with cytotoxic activity towards solid tumor cells, especially in their first stage of growth, which is characterized by low oxygen concentration. Bioreductive agents represent a class of prodrugs that target hypoxic tumor cells. Their bioactivity depends on the reactivity of their functional chemical groups. Their efficacy requires metabolic reduction and subsequent generation of toxic prodrugs. Chemoresistance of tumor cells is a major problem for successful antitumor therapy for many types of tumors, especially for breast cancer. The present study was performed to assess the effect of the antiproliferation activity of the tested benzimidazoles by way of NF-κB expression inhibition. The activity of the tested compounds on T47D and MCF7 cells was examined by WST, western blot, NF-κB transactivation assay, and apoptotic cell population analysis. Compound 3 was highly cytotoxically active against T47D cells, especially in hypoxic conditions. Its IC50 of 0.31 ± 0.06 nM, although weaker than tirapazamine, was significantly higher than the other tested compounds (2.4–3.0 fold). The increased bax protein expression upon exposure to the tested compounds indicated intercellular apoptotic pathway activity, with tumor cell death by way of apoptosis. Increased bax protein synthesis and apoptotic cell dominance upon treatment, especially with N-oxide derivatives (92% apoptotic cells among T47D cell populations during treatment with compound 3), were correlated with each other. Additionally, both increased bax protein and decreased NF-κB protein expression supported antiproliferative activity via NF-κB–DNA binding inhibition associated with the tested compounds. Compound 3 appeared to be the strongest inhibitor of NF-κB expression in hypoxic conditions (the potency against NF-κB expression was about 75% of that of tirapazamine). The present studies involving this class of heterocyclic small molecules proved their potential usefulness in anticancer therapy as compounds be able to limit tumor cell proliferation and reverse drug resistance by NF-κB repression

New Generation of Meso and Antiprogestins (SPRMs) into the Osteoporosis Approach

Receptor activator of nuclear factor κB (RANK) and its ligand (RANKL) play key roles in bone metabolism and the immune system. The RANK/RANKL complex has also been shown to be critical in the formation of mammary epithelia cells. The female hormones estradiol and progesterone closely control the action of RANKL with RANK. Blood concentration of these sex hormones in the postmenopausal period leads to an increase in RANK/RANKL signaling and are a major cause of women’s osteoporosis, characterized by altered bone mineralization. Knowledge of the biochemical relationships between hormones and RANK/RANKL signaling provides the opportunity to design novel therapeutic agents to inhibit bone loss, based on the anti-RANKL treatment and inhibition of its interaction with the RANK receptor. The new generation of both anti- and mesoprogestins that inhibit the NF-κB-cyclin D1 axis and blocks the binding of RANKL to RANK can be considered as a potential source of new RANK receptor ligands with anti-RANKL function, which may provide a new perspective into osteoporosis treatment itself as well as limit the osteoporosis rise during breast cancer metastasis to the bone

Biological Evaluation of the Activity of Some Benzimidazole-4,7-dione Derivatives

The study presented here is a follow up of the authors’ interest in the approach to selective and cytotoxic bioreductive anticancer prodrugs. The current work is devoted to explore both the biological activity of some previously obtained compounds and the search for an explanation of their target(s) in hypoxic pathways. In this work the biological activity of some benzimidazole-4,7-diones was evaluated. These compounds were examined as potential bioreductive agents specific for the hypoxic environment found in tumor cells. The main aim was concerned with establishing their cytotoxic properties by using proliferation, apoptosis and DNA destruction tests on selected tumor cells. Their cytotoxic effects on two tumor cell lines (human lung adenocarcinoma A549 cells line and human malignant melanoma WM115) was compared by means of a WST-1 test. Next, the mode of cytotoxicity behind the selected tumor cells’ death was determined by the caspase 3/7 test. The last point referred to the DNA destruction of A549 and WM115 cells and the in situ DNA Assay Kit test was applied. The cytotoxic tests confirmed their activity against the tumor cells and target hypoxia (compounds 2b, 2a, 2d). The screening test of the caspase-dependent apoptosis proved that the exposure of the tested tumor cells in hypoxia to these benzimidazole-4,7-diones promoted the apoptotic cell death. Additionally, the DNA damage test established that benzimidazole-4,7-diones can be potential hypoxia-selective agents for tumor cells, especially compound 2b. All results classify the tested benzimidazole-4,7-diones as promising, lead molecules and provide a rationale for further molecular studies to explain their usefulness as potential inhibitors of the hypoxia-inducible factor 1 (HIF1)

Antiproliferative activity of new benzimidazole derivatives

A series of new benzimidazole derivatives were synthesized and tested in vitro for possible anticancer activity. Their effect of proliferation into selected tumor cell lines at normoxia and hypoxia conditions was determined by WST-1 test. Additionally, apoptosis test (caspase 3/7 assay) was used to check the mode caused by the agents of cell death. Four of the examined compounds (7, 8, 13, 11) showed a very good antiproliferative effect and three of them were specific for hypoxia conditions (8, 14, 11). Compound 8 was the most cytotoxic against human lung adenocarcinoma A549 cells at hypoxic conditions. Hypoxia/ normoxia cytotoxic coefficient of compound 14 (4.75) is close to hypoxia/normoxia cytotoxic coefficient of tirapazamine (5.59) - a reference compound in our experiments and this parameter locates it between mitomycin C and 2-nitroimidazole (misonidazole). Screening test of caspase-dependent apoptosis proved that exposure to A549 cells of compounds 7-8 and 13-14 for 48 h promote apoptotic cell death. These results supplement our earlier study of the activity of new potentialy cytotoxic heterocyclic compounds against selected tumor cells