Os pacientes submetidos ao tratamento antineoplásico necessitam de um acesso venoso que permita a infusão segura das drogas quimioterápicas, evitando assim o risco do extravasamento. O extravasamento quimioterápico é definido como o escape de drogas do vaso sanguíneo para os tecidos circunjacentes, e seus efeitos tóxicos locais variam podendo causar dor, necrose tissular ou descamação do tecido. A morbidade depende do tipo da droga, da quantidade extravasada, da sua concentração, da localização do extravasamento, das condições do paciente e do intervalo entre o fato, seu reconhecimento e o tratamento. A prática baseada em evidências é uma abordagem que capacita os profissionais buscarem a melhor evidência para o cuidado, respeitando a opinião dos pacientes e seus familiares. O presente estudo é uma revisão integrativa da literatura, que teve como objetivo buscar e avaliar as evidências disponíveis na literatura sobre as intervenções eficazes frente ao extravasamento de drogas quimioterápicas vesicantes, em cateteres periféricos, prevenindo e minimizando lesões no paciente adulto oncológico. Para a seleção dos artigos utilizamos a base de dados Medline, e a amostra constituiui-se de 16 artigos. As medidas de prevenção do extravasamento são consideradas mais eficazes e recomendadas. Para o manejo do extravasamento das drogas doxorrubicina e epirrubicina é recomendado aplicação de gelo local, os antídotos dimetilsulfoxide tópico e dexrazoxane intravenoso, intervenção cirúrgica se houver persistência dos sintomas ou para grande quantidade de droga extravasada. Para o extravasamento de mitomicina C, gelo local e intervenção cirúrgica em lesões detectadas após 48 horas; para mecloretamina é indicado gelo e o antídoto tiossulfato de sódio. Para o manejo da vinorelbine é recomendado calor local e o antídoto hialuronidase por via subcutânea. As evidências extraídas dos estudos analisados podem auxiliar a implementação de cuidados de enfermagem eficazes relacionados ao extravasamento das drogas vesicantes contribuindo assim com a melhoria da assistência à saúde. / Patients submitted to antineoplastic chemotherapy need a venous access that allows for the safe infusion of chemotherapeutic drugs, thus avoiding the risk of chemotherapeutic extravasation. Chemotherapeutic extravasation is defined as the escape of drugs from the blood vessel to surrounding tissues. Its local toxic effects vary and can cause pain, tissue necrosis or flaking. Morbidity depends on the type of drug, the extravasated quantity, its concentration, the location of the extravasation, the patient s conditions and the interval between the fact and its recognition and treatment. Evidence-based practice is an approach that trains professionals to look for the best evidence for care, respecting the opinions of patients and their relatives. This study is an integrative literature review that aimed to look for and assess available evidence in literature about effective interventions in case of extravasation of vesicant chemotherapeutic drugs, in peripheral catheters, minimizing skin injuries of adult cancer patients. To select the articles, we used the database Medline, and the sample consisted of 16 articles. Extravasation prevention measures are considered as the most effective and recommended measures. To handle the extravasation of doxorubicin and epirubicin, the local application of ice is recommended, the antidotes topic dimethyl sulphoxide and intravenous dexrazoxane, and surgical intervention if the symptoms persist or if a large quantity of the drug has extravasated. For the extravasation of mitomycin C, local ice and surgical intervention in injuries detected after 48 hours; for mecloretamine, ice is indicated, as well as the antidote sodium thiosulphate. To handle vinorelbine, local heat is recommended, as well as the subcutaneous application of the antidote hyaluronidase. The evidence extracted from the analyzed studies can support the implementation of effective nursing care related to the extravasation of vesicant drugs, thus contributing to the improvement of nursing care.

O câncer é umas das principais causas de morte no mundo. Com a falta de critério individual para o tratamento de câncer metastático, a quimioterapia ainda é realizada com fármacos de toxicidade significativa como antraciclinas e taxanos. Portanto, a busca por novos fármacos é de suma importância. Os alquilfosfolipídios constituem uma nova classe de fármacos antineoplásicos, tendo como protótipo a miltefosina, empregada para o tratamento tópico de metástases cutâneas de câncer de mama. No entanto, este fármaco apresenta toxicidade gastrointestinal e ação hemolítica. Neste trabalho, investigou-se a rota sintética da miltefosina, bem como a síntese de novos análogos cicloalquílicos possivelmente menos hemolíticos e menos tóxicos. Para a síntese da miltefosina, 4 etapas foram realizadas: a) obtenção do Dicloreto de fosforoexadecila; b) obtenção de 2-(hexadeciloxi)-3-metil-oxa-1,3,2- oxazofosfolano; c) obtenção do fosfato de 2-(metilamino) etil hexadecila; d) obtenção da miltefosina (hexadecilfosfocolina); sendo o fármaco obtido com sucesso. Em seguida, metodologias de monossubstituição em dióis simétricos foram investigadas para obtenção de ω-hidroxidecil-cicloalquilmetil éteres a serem empregados na rota da miltefosina visando análogos alcoxicicloalquilicos. Diversas tentativas foram empregadas sem sucesso, impedindo-nos de dar continuidade à síntese destes análogos. Partindo-se do reagente cicloexanoetanol e empregando-se a rota de síntese aprimorada da miltefosina, obtivemos o intermediário fosfato de 2-(metilamino)etil cicloexila puro. A última etapa, referente à metilação da amina, resultou em composto dimetilado ao invés do trimetilado esperado. Um ajuste dos parâmetros reacionais como, por exemplo, aumento da concentração dos reagentes de partida, deve resultar no composto planejado. Tanto o intermediário obtido quanto o análogo desejado poderão ser futuramente ensaiados quanto à atividade antitumoral e potencial hemolítico. / Cancer is one of the major causes of death worldwide. Due to the lack of individual standard treatment for metastatic cancer, chemotherapy is still based in the use of significantly toxic drugs like anthracyclines and taxanes. Hence, there is a need to search for new anticancer agents. Alkylphospholipids recently emerged as a new antitumor class and its lead compound, miltefosine, has been used for the topical treatment of cutaneous metastasis in breast cancer. However, this drug exhibits gastrointestinal toxicity and hemolytic activity. We investigated miltefosine synthetic route as well as the synthesis of cycloalkyl analogues possibly less toxic and hemolytic. We started from miltefosine synthesis, which included four steps: a) generation of hexadecyl phosphorodichloridate; b) generation of 2-(hexadecyloxy)-3-methyl-oxo-1,3,2-oxazaphospholane; c) generation of hexadecyl 2-(methylamino) ethyl phosphate; d) production of the final product miltefosine (hexadecylphosphocholine). The route was optimized, resulting in the desired drug. After that, several methods for symmetrical diols monoprotection were investigated aiming at the generation of ω-hydroxydecyl cycloalkylmethyl ethers to be further employed in miltefosine synthetic route aiming at alkoxycycloalkyl analogues. Several attempts were realized however unsuccessfully, preventing us to move on in these analogues synthesis. In a different approach, we started from cyclohexylethanol and, employing the synthetic route of miltefosine, obtained the third intermediate, 2-cyclohexylethyl 2- (methylamino)ethyl phosphate pure. The methylation step, last one to obtain the cycloalkyl analogue, resulted in a dimethyl analogue instead of a trymethyl one. We believe that adjusting the reaction parameters, such as increasing reagents concentrations, should result in a successful methylation step. The intermediate obtained as well as the analogue planned might be future evaluated in terms of hemolytic potential and antitumor activity.

Os tumores de cabeça e pescoço ocupam o sexto lugar no ranking de incidência mundial, e estão localizados na região da face, fossas nasais, seios paranasais, boca, faringe, laringe entre outros tecidos moles do pescoço. O tabagismo, o etilismo, a radiação solar e o vírus HPV, são fatores de risco associados a esse tipo de tumors. A terapia combinada de drogas antineoplásicas tem sido utilizada para amenizar os efeitos colaterais e potencializar o tratamento antitumoral. A combinação de paclitaxel e cisplatina tem se mostrado eficaz em tumores sólidos, como o HNSCC. A morte celular induzida pelo paclitaxel é mediada pela ruptura da dinâmica dos microtúbulos normais, já a cisplatina induz ligações cruzadas de DNA estes tratamentos induzem a célula à morte por apoptose. A apoptose é um processo de morte dividido, didaticamente, em via intrínseca (via mitocondrial) e via extrínseca (via receptor de morte). Entender por qual via essas células tumorais são induzidas a morte é fundamental para tentar evitar a resistência dessas células ao tratamento. Nosso objetivo é entender se células tumorais de HNSCC são resistentes ou sensíveis ao tratamento com paclitaxel e cisplatina sozinhos ou em associação. Para isso, realizamos o tratamento da linhagem celular FaDu por um período de 48 horas com as drogas e verificamos sua resistência a indução de morte por esses tratamentos. Os resultados mostraram que o tratamento com paclitaxel não potencializa a morte desta célula, sendo a linhagem FaDu mais sensível ao tratamento com cisplatina e a associação apresenta o mesmo perfil de quando tratada com cisplatina. A morte desta linhagem é dependente de caspases e possui uma preferência pela via extrínseca da apoptose que, consequentemente, induz a morte também pela via intrínseca. A modulação desta morte se dá pelo balanço das proteínas pró- e anti-apoptóticas da família BCL-2 que são responsáveis pela regulação da apoptose, o tratamento com cisplatina induz a expressão da proteína pró-apoptótica BAK e a diminuição das proteínas anti-apoptóticas BCL-2 e BCL-XL. Com os resultados obtidos, concluímos que a associação de paclitaxel e cisplatina não potencializa a morte da linhagem celular FaDu. Contudo, a cisplatina apresentou-se efetiva na indução de morte por apoptose através do aumento da expressão da proteína BAK e a diminuição da expressão das proteínas BCL-2 e BCL-XL. / Head and neck squamous cell carcinoma is the sixth most common cancer in the world, and are located in the region of the face, nasal fossas, sinuses, mouth, pharynx, larynx and other soft tissues of the neck. Tobacco smoke, etilism, solar radiation and HPV are risk factors associated with this type of tumors. Combination therapy of anticancer drugs has been used to alleviate the side effects and potentiate the antitumor treatment. The combination of paclitaxel and cisplatin has been shown to be effective in solid tumors such as HNSCC. The paclitaxel-induced cell death is mediated by disruption of the normal microtubule dynamics, and the cisplatin induced DNA cross-links, these treatments induce cell death by apoptosis. Apoptosis is a death process divided in, intrinsic pathway (mitochondrial pathway) and extrinsic pathway (death receptor pathway). Understand by what pathway those tumor cells which are induced death is important to try and avoid the resistance of these cells to treatment. Our aims understand if HNSCC tumor cells are resistant or sensitive to treatment with paclitaxel and cisplatin alone or in combination. We carried out the treatment of cell line FADU a period of 48 hours with the drug and we verify their resistance to death induction by these treatments. The results showed that treatment with paclitaxel did not potentiate the cell death, in the other hand, FADU cell line appeared to be more sensitive to cisplatin treatment, and the association has the same profile when treated with cisplatin. The death of this line is dependent on caspases and has a preference for the extrinsic pathway of apoptosis, consequently, also induces the death by the intrinsic pathway. The modulation of death is caused by the balance of pro-and anti-apoptotic proteins of BCL-2 family proteins that are responsible for regulation of apoptosis, treatment with cisplatin induces the expression of pro-apoptotic protein BAK and the decrease of anti-apoptotic proteins BCL -2 and BCL-XL. With these results, we conclude that the combination of paclitaxel and cisplatin did not potentiate the cell death of the cell line Fadu. However, cisplatin showed to be effective in induction of death by apoptosis through increased expression of BAK protein and decreased expression of BCL-2 and BCL-XL.

Carbon dots (CDs) have attracted much attention as an excellent gene/drug delivery and biological imaging agent for early cancer theranostics. In this study, we prepared two series of nanoparticles (NPs), which are composed of (CDs) with a targeting agent, folic acid (FA), and a chemotherapeutic agent Doxorubicin (Dox). All the NPs and their intermediates were characterized using ultraviolet-visible spectroscopy (UV-vis), fluorescence spectroscopy, and Fourier transform-infrared spectroscopy (FT-IR). The drug loading capacity (DLC) and drug loading efficiency (DLE) of two series of FA-CDs-Dox were assessed using UV-vis absorption spectroscopy at the wavelength of 485 nm. Both showed good DLE and DLC results when compared to literature data. In addition, the cumulative release property of Dox from the FA-CDs-Dox complexes were investigated in a pH solution of 7.4.

>Magister Scientiae - MSc / Retinoblastoma Binding Protein 6 (RBBP6) is a 200 KDa multi-domain protein that has been shown to play a role in mRNA processing, cell cycle arrest and apoptosis. RBBP6 interacts with tumour suppressor proteins such as p53 and pRb and has been shown cooperate with Murine Double Minute 2 (MDM2) protein in catalyzing ubiquitination and suppression of p53. Unpublished data from our laboratory has suggested that RBBP6 and MDM2 interact with each other through their RING finger domains. RBBP6 has also been shown to have its own E3 ubiquitin ligase activity, catalyzing ubiquitination of Y-Box Binding Protein 1 (YB-1) in vitro and in vivo. YB- 1 is a multifunctional oncogenic protein that is generally associated with poor prognosis in cancer, tumourigenesis, metastasis and chemotherapeutic resistance. Unpublished data from our laboratory shows that RBBP6 catalyzes poly-ubiquitination of YB-1, using Ubiquitin-conjugating enzyme H1 (UbcH1) as E2 ubiquitin conjugating enzyme. / 2022-02-25

No description available.

No description available.

<p>Cytochrome b5 heme binding domain 2 (CYB5D2) is a heme binding protein that was initially identified for its ability to attenuate the function of the PTEN tumor suppressor gene. CYB5D2 sustains ectopic PTEN expression in U87 cells, and can also confer survival from serum starvation in NIH3T3 cells. An antibody was generated to the carboxyl terminus of CYB5D2 to detect endogenous protein expression. The highest expression of CYB5D2 protein is in neural cancer cell lines. CYB5D2 is weakly expressed in breast and kidney cancer cell lines, and moderately expressed in prostate cancer cell lines. To investigate the role of the heme binding domain in CYB5D2, a conserved aspartic acid (D86) within this domain was mutated to glycine, and this was characterized as being unable to bind heme. CYB5D2(D86G) displayed a loss of function compared to wild-type CYB5D2. To study the loss of expression of CYB5D2, stable CYB5D2 shRNA was achieved in HeLa and Huh7 cells. While ectopic CYB5D2 inhibited HeLa cell proliferation and growth in soft agar, CYB5D2(D86G) expression and CYB5D2 shRNA increased cell proliferation and soft agar growth. While ectopic CYB5D2 conferred survival from chemotherapeutic drugs in HeLa cells, CYB5D2(D86G) and CYB5D2 shRNA cells were susceptible to drug treatments. CYB5D2 inhibits SREBP signalling, which requires its heme binding ability. Using cyclohexamide treatments, CYB5D2 stabilized ectopic Insig1, while CYB5D2(D86G) destabilized ectopic Insig1. CYB5D2 shRNA reduced endogeneous CYP51A1 (lanosterol demethylase) and Insig1 protein levels, and increased the susceptibility of HeLa cells to mevalonate treatments. Furthermore, CYB5D2 shRNA HeLa cells displayed reduced CYP3A4 activity, a cytochrome P450 enzyme involved in drug metabolism. CYB5D2 binds to cytochrome P450 reductase (POR), while CYB5D2(D86G) cannot. CYB5D2 co-immunoprecipitates with endogenous POR under serum-free conditions in HeLa and Huh7 cells, while CYB5D2(D86G) cannot. Collectively, CYB5D2 is a POR interacting protein, which regulates CYP51A1 and CYP3A4 activity.</p> / Doctor of Philosophy (Medical Science)

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Introduction: Mammalian circadian rhythms form an integral physiological system allowing for the synchronisation of all metabolic processes to daily light/dark cycles, thereby optimising their efficacy. Circadian disruptions have been implicated in the onset and progression of different types of cancers, including those arising in the breast. Several links between the circadian protein Per2 and DNA damage responses exist. Aberrant Per2 expression results in potent downstream effects to both cell cycle and apoptotic targets, suggestive of a tumour suppressive role for Per2. Due to the severe dose limiting side effects associated with current chemotherapeutic strategies, including the use of doxorubicin, a need for more effective adjuvant therapies to increase cancer cell susceptibility has arisen. We therefore hypothesize, that the manipulation of the circadian Per2 protein in conjunction with doxorubicin may provide a more effective chemotherapeutic strategy for the treatment of breast cancer. The aims of this project were thus to: (i) Characterize the role of Per2 in normal breast epithelial cells as well as in ER+ and ER- breast cancer cells; (ii) to determine the role of Per2 in doxorubicin-induced cell death, (iii) to determine the role of Per2 in autophagy and finally (iv) to assess whether the pharmacological inhibition of Per2 with metformin, can sensitize chemo-resistant MDA-MB-231 breast cancer cells to doxorubicin-induced cell death. Methods: An in vitro model of breast cancer was employed using the normal MCF-12A breast epithelial, estrogen receptor positive (ER+) MCF-7 and estrogen receptor negative (ER-) MDA-MB-231 breast adenocarcinoma cell lines. Circadian rhythmicity of Per2 protein expression was determined using western blotting, and Per2 cellular localization was assessed using fluorescent confocal microscopy. Per2 was then silenced by means of an endoribonuclease-prepared siRNA, and silencing efficiency was determined with the use of western blotting. The roles of Per2 in doxorubicin-induced cell death and autophagy were assessed by treating MDA-MB-231 breast cancer cells under the following conditions (1) Control, (2) 2.5 μM doxorubicin or 10 nM bafilomycin A1 (3) 30 nM esiPer2 and (4) 30 nM esiPer2 in combination with 2.5 μM doxorubicin or 10 nM bafilomycin A1. Following treatments cell viability was assessed using the MTT assay, western blotting for markers of apoptosis including p-MDM2 (Ser166), p-p53 (Ser15), cleaved caspase-3 and –PARP as well as markers of autophagy (AMPKα, mTOR and LC3). Furthermore, cell cycle analysis, G2/M transition and cell death (Hoechst 33342 and propidium iodide staining) were assessed by means of flow cytometry. The pharmacological inhibition of Per2 was achieved by treating MDA-MB-231 cells with 40 mM metformin as well as in combination with 2.5 μM doxorubicin. MTT cell viability assays, cell cycle analysis (flow cytometry) and western blotting for apoptosis (Per2, p-AMPKα (Thr172), p53, caspase-3 and PARP) were assessed. Results and discussion: A circadian pattern of Per2 protein expression was observed in the normal MCF-12A and MDA-MB-231 cancer cells with protein levels peaking at ±700% and ±500% of baseline was observed. However, no rhythmic expression was observed in the MCF-7 cancer cells. Immunostaining for Per2 showed localization OF Per2 in the cytoplasm as well as in the nucleus of both the MCF-12A and MDA-MB-231 cells. Concentration curves showed a significant reduction in cell viability following 2.5 μM doxorubicin treatment for 24 hours. Per2 protein expression was significantly reduced with both esiPer2 and metformin treatment. Silencing of Per2 in combination with doxorubicin treatment resulted in cell cycle arrest with a significant increase in apoptosis, indicating that Per2 silencing effectively sensitized the MDA-MB-231 cancer cells to the anti-carcinogenic properties of doxorubicin. Modulation of Per2 protein expression was effectively achieved with the use metformin although this decrease occurred independently of AMPKα phosphorylation. A significant increase in apoptosis was observed following treatment with metformin in combination with doxorubicin treatment. However, no changes in cell cycle regulation were observed. Per2 appears to be involved in the regulation of autophagy as a significant increase in autophagy flux was observed when Per2 was silenced. Additionally, this increase in autophagic flux resulted in a significant increase in MDA-MB-231 cancer cell death which was enhanced further when autophagy was inhibited with bafilomycin A1 subsequent to Per2 silencing. Conclusions: Per2 protein expression was shown to display a 24 hour circadian rhythm in the MCF-12A cells, and to a lesser extent in the MDA-MB-231 cells. However, the MCF-7 cells failed to show rhythmic changes in Per2 protein expression. Per2 was shown to be located predominantly in the cytoplasm, with nuclear localization observed when cytoplasmic fluorescent intensity was lower. Per2 silencing effectively sensitized the chemo-resistant MDA-MB-231 breast cancer cells to both doxorubicin-induced cell death and autophagic inhibition. / AFRIKKANSE OPSOMMING: Inleiding: Sirkadiese ritmes vorm ‘n integrale fisiologiese sisteem wat die sinkronisasie van alle metaboliese prosesse asook lig/donker siklusse se effektiwiteit optimaliseer. Onderbreking van hierdie sirkadiese ritmes word geïmpliseer in die ontstaan en bevordering van verskillende kankertipes, insluitend borskanker. Verskeie raakpunte bestaan tussen die sirkadiese proteïen, Per2, en die DNA skade-respons. Abnormale Per2 uitdrukking veroorsaak afstroom effekte op beide die selsiklus en apoptotiese teikens wat moontlik aanduidend van ‘n tumor-onderdrukkende rol vir Per2 kan wees. Daar bestaan ‘n groot nood vir meer effektiewe adjuvante terapieë om kankersel vatbaarheid vir chemoterapie te verhoog as gevolg van dosis-beperkende newe-effekte wat geassosieer word met huidige chemoterapeutiese strategieë, insluitende dié van doxorubicin. Ons hipotese is dus dat die manipulering van die sirkadiese Per2 proteïen tesame met doxorubicin ‘n meer effektiewe chemoterapeutiese strategie vir die behandeling van borskanker sal wees. Die doelwitte van hierdie projek was dus om: (i) Die rol van Per2 in normale borsepiteelselle sowel as in ER+ en ER- borsepiteel kankerselle te karakteriseer; (ii) die rol van Per2 in doxorubicin-geïnduseerde seldood te bepaal; (iii) te bepaal of Per2 ‘n rol in autofagie speel en laastens (iv) te bepaal of die farmakologiese inhibisie van Per2 met metformin chemo-weerstandbiedende MDA-MB-231 kankerselle kan sensitiseer vir doxorubicin-geïnduseerde seldood. Metodes: ‘n In vitro model vir borskanker is gebruik wat normale MCF-12A borsepiteelselle, estrogeen reseptor positiewe (ER+) MCF-7 en estrogeen reseptor negatiewe (ER-) MDA-MB-231 bors adenokarsenoomselle insluit. Sirkadiese ritmisiteit van Per2 proteïen uitdrukking is deur middel van die westelike kladtegniek bepaal en die sellulêre ligging van Per2 deur middel van fluoresensie mikroskopie. siPer2 is voorberei deur middel van endoribonuklease-siRNA en die effektiwiteit daarvan is deur middel van westelike kladtegniek getoon. Die rol van Per2 in doxorubicin-geinduseerde seldood en autofagie is bepaal deur MDA-MB-231 borskankerselle onder die volgende omstandighede te toets: (1) Kontrole, (2) 2.5 μM doxorubicin of 10 nM bafilomycin A1 (3) 30 nM esiPer2 en (4) 30 nM esiPer2 in kombinasie met 2.5 μM doxorubicin of 10 nM bafilomycin A1. Na die behandeling, is sellewensvatbaarheid bepaal deur gebruik te maak van ‘n MTT toets; westelike kladtegniek is gebruik om vir merkers van apoptose soos p-MDM2 (Ser166), p-p53 (Ser15), gekliefde caspase-3 en -PARP asook vir merkers van autofagie (AMPKα, mTOR en LC3) te toets. Die selsiklus, G2/M oorgang en seldood (Hoechst 33342 en propidium iodide kleuring) is deur middel van vloeisitometrie bepaal. Per2 is ook farmakologies geïnhibeer deur MDA-MB-231 selle met 40 mM metformin asook in kombinasie met 2.5 μM doxorubicin te behandel. Daarna is sellewensvatbaarheid (MTT) sowel as die selsiklus (vloeisitometrie) en apoptose (westelike kladtegniek vir Per2, p-AMPKα (Thr172), p53, caspase-3 and PARP) gemeet. Resultate en bespreking: ‘n Sirkadiese patroon vir Per2 proteïen uitdrukking is in die normale MCF-12A selle asook in die MDA-MB-231 kankerselle waargeneem met proteïenvlakke wat hul piek by ±700% and ±500% onderskeidelik in vergelyking met basislyn bereik het. Geen ritmiese patroon van Per2 proteïen uitdrukking is egter in die MCF-7 kankerselle waargeneem nie. Immunokleuring om Per2 ligging te bepaal het getoon dat Per2 in the sitoplasma sowel as in die nukleus in beide MCF-12A en MDA-MB-231 selle voorgekom het. Konsentrasie kurwes het aangetoon dat daar ‘n insiggewende vermindering in sellewensvatbaarheid voorgekom het na die behandeling van die selle met 2.5 μM doxorubicin vir 24 uur. Per2 proteïen uitdrukking is insiggewend verlaag met beide esiPer2 en metformin behandeling van die selle. esiPer2 aleen of in kombinasie met doxorubicin behandeling het selsiklus staking tot gevolg gehad asook ‘n beduidende toename in apoptose veroorsaak wat dus aangedui het dat esiPer2 effektief was om MDA-MB-231 kankerselle te sensitiseer vir die anti-karsinogeniese doxorubicin behandeling. Modulering van Per2 proteïen uitdrukking was effektief met metformin behandeling, alhoewel die afname onafhanklik van AMPKα fosforilasie plaasgevind het. ‘n Insiggewende toename in apoptose is waargeneem na metformin behandeling in kombinasie met doxorubicin. Geen veranderinge in die selsiklus is egter onder hierdie omstandighede waargeneem nie. Per2 blyk betrokke te wees in die regulering van autofagie aangesien ‘n insiggewende verhoging in autofagie omsetting waargeneem is na esiPer2 behandeling. Die toename in autofagie omsetting is geassosieer met ‘n insiggewende toename in seldood in MDA-MB-231 kankerselle wat verder verhoog is wanneer autofagie met bafilomycin A1 (autofagie inhibitor) in kombinasie met esiPer2 behandel is. Gevolgtrekkings: Per2 proteïen uitdrukking het ‘n 24 uur sirkadiese ritme in die MCF-12A normale selle, en tot ‘n mindere mate in die MDA-MB-231 selle getoon. Die MCF-7 selle het egter geen ritmiese patroon van Per2 proteïen uitdrukking getoon nie. Per2 kom hoofsaaklik in die sitoplasma voor en het slegs in die nukleus voorgekom wanneer die sitoplasmiese fluoresensie intensiteit laer was. esiPer2 was dus effektief om die chemo-weerstandbiedende MDA-MB-231 borskankerselle te sensitiseer vir doxorubicin-geïnduseerde seldood. / National Research Foundation

O Melanoma é um tipo de neoplasia que se origina de melanócitos normalmente presentes na epiderme. Uma das características do melanoma é a capacidade de adquirir resistência a terapias. As células de melanoma podem aumentar a liberação de vesículas extracelulares (VEs) em resposta ao tratamento com quimioterápicos. A cisplatina (CDDP) e a temozolomida (TMZ) são drogas utilizadas para o tratamento de tumores. Ambas as drogas formam adutos no DNA, mas as vias de sinalização que deflagram a morte celular são distintas. O objetivo desse estudo é investigar a morte celular da linhagem B16-F10 na presença de VEs oriundas de células B16-F10 tratadas com cisplatina CDDP ou TMZ. Inicialmente as VEs oriundas de células de melanoma murino, B16-F10, tratadas com CDDP ou TMZ e seus controles, foram isoladas por ultracentrifugações sucessivas. Para os experimentos in vitro, as células foram tratadas com as drogas em combinação com as respectivas VEs. As amostras foram realizados avaliações de ciclo celular e de morte e ensaio clonogênico. Para os experimentos in vivo, as células B16-F10 foram pré-tratadas com VEs, e posteriormente, as células foram inoculadas via subcutânea em camundongos C57BL/6 e os tumores foram mensurados diariamente. Em nosso estudo concluimos que a metodologia do isolamento de VEs é eficiente. Além disso, observamos que o tratamento com CDDP ou TMZ aumenta a liberação de VEs por células tumorais. Apesar do resultado contraditorio, as VEs liberadas por células tumorais tratadas com quimioterápicos aumentam a capacidade de sobrevivência das células de melanoma in vitro. VEs oriundas de células de melanoma não participam inicialmente da sensibilização à morte de células tumorais causada pelas mesmas drogas, mas a longo prazo, as VEs oriundas de células tratadas com a TMZ podem conferir uma resposta celular de sobrevivência às células tumorais in vitro. In vivo, o resultado é inconclusivo, uma vez que para confirmar se as VEs fazem parte da adaptação tumoral conferindo fenômenos de sobrevivência celular in vivo, é necessário avaliar em outros modelos celulares e animais / Melanoma is a neoplasm derived from melanocytes normally present in the skin specifically in the epidermis. One of the malignancies of melanoma is the ability to acquire chemoresistance. Cisplatin (CDDP) and temozolomide (TMZ) are drugs used for the treatment of tumors. Both drugs can form alkylating adducts in DNA, however, the pathways that trigger cell death are distinct. Tumor cells, including melanoma, may increase the release of extracellular vesicles (EVs) in response to chemotherapeutic treatment. The aim of this study is to investigate the cell death phenomenon in B16-F10 cell line in presence of EVs derived from chemotherapeutic-treated B16-F10 cells. For in vitro experiments, the cells were treated with CDDP or TMZ in combination with EVs from chemotherapictreated samples. For in vivo experiments, B16-F10 cells were exposed to EVs and inoculated subcutaneously in C57BL/6 mice. The growth was measured daily. In this work, we established and characterized VEs released by melanoma cells treated with chemotherapics and we established chemotherapics treatments to isolate EVs for next EVs isolation. Our results showed that CDDP or TMZ treatment increase the release of EVs by tumor cells. The EVs released by melanoma cells after CDDP or TMZ treatment seem to increase the survival capacity of melanoma cells. Thus, we concluded that EVs derived from melanoma cells do not participate in the cell death sensitization induced by CDDP or TMZ. However, EVs derived from TMZ treated cells may offer a survival effect to tumor cells in vitro a long term. In vivo, The result is inconclusive since to confirm how VEs are part of the tumor adaptation conferring cellular survival phenomena in vivo, it is necessary to evaluate in other cellular and animal models