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Background: Cancer is a complex disease that is derived from the uncontrolled proliferation of cells. Bone cancer is a type of prevalent cancer that occurs both in youngsters and adults. Bone cancer is mostly common in the long bones of the pelvis, arms, and legs. Statistically, more than 200 cases of osteosarcoma have been reported annually in our country. Classical treatment with chemotherapeutics remains ineffective for the cure of this cancer. Recent studies have shown that ceramide induces apoptosis due to its increased levels in the cells. Thus, many studies have been conducted for the accumulation of ceramide molecules in the cell by different ways to induce apoptosis. NOE (N-oleoylethanolamine) is a specific inhibitor of ceramidase enzymes that hydrolyse intracellular ceramides and prevent apoptosis. Objective: This study investigates the cytotoxic and apoptosis-inducing activities of NOE on human osteosarcoma Saos-2 cells. Methods: Cytotoxic effects were investigated by MTT colorimetric assay. For the detection of morphological and ultrastructural indicators of apoptosis, confocal and TEM techniques were used, respectively. Results: Our finding indicated that NOE is effective in the inhibition of the growth of Saos-2 cells. Confocal and TEM findings showed morphological and ultrastructural changes as chromatin condensation, fragmentations of nuclei and mitochondria, as well as damaged cytoskeleton and cell shrinkage. Conclusion: The results revealed that NOE exhibits its cytotoxicity on Saos-2 cells by changing the ultrastructure and morphology of cells with clear apoptotic sparks.

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Introduction Large scale sequencing studies have identified that 93% of the colorectal cancer (CRC) patients carry at least one mutation in genes implicated in Wnt signalling pathway. Notably, majority of the CRC patients (88%) carry either APC or b-catenin mutations that can activate the Wnt signalling pathway. Recent evidences suggest that Wnt/b-catenin signalling activity is regulated by CDH17 in hepatocellular carcinoma. As CDH17 is exclusively expressed in the intestine and overexpressed in CRC, we hypothesised that CDH17 could be utilised as a therapeutic target to treat CRC patients. Material and methods RNA interference-based stable knockdowns were established in a panel of CRC cells with varying mutations in APC and b-catenin. Wnt signalling activity of the cells were measured by TOPflash assay. Apoptosis studies were performed using fluorescence activated cell sorting. Cells were further subjected to immunoprecipitations with anti-CDH17 and anti-b-catenin antibodies followed by label-free quantitative proteomics analysis. A monoclonal antibody was developed to block CDH17 and sensitise CRC cells to chemotherapeutic drugs. Results and discussions Knockdown of CDH17 in CRC cells downregulated b-catenin and attenuated Wnt signalling activity irrespective of APC and/or b-catenin mutations. Furthermore, CDH17 silencing induced apoptosis and sensitised CRC cells to the chemotherapeutic drugs 5-Fluorouracil. Immunoprecipitations using anti-CDH17 and anti-b-catenin antibodies followed by label-free quantitative proteomics analysis highlighted no direct interaction between CDH17 and b-catenin hence implying an indirect regulation of b-catenin expression and Wnt signalling pathway by CDH17. The analysis revealed Ecadherin and FAT1 as common interactors of CDH17 and bcatenin. Quantitative proteomic analysis of cell lysates revealed the upregulation of FAT1, a negative regulator of Wnt signalling pathway, upon knockdown of CDH17. Monoclonal antibodies developed against CDH17 were able to increase apoptosis and sensitivity of CRC cells to 5-Fluorouracil. Conclusion Overall, these findings suggest that CDH17 can attenuate Wnt signalling pathway and induce apoptosis irrespective of the APC and b-catenin mutational status. As Wnt signalling pathway is aberrated in 93% of CRC patients, the membrane protein CDH17 can be exploited as therapeutic target to treat CRC.

Akciğer kanseri dünyada yüksek ölüm oranlarına sahip olan bir kanser türüdür. Bitkilerde doğal olarak bulunan polifenollerin antioksidan özellikleri bilinmektedir. Polifenoller biyolojik aktiviteleri, besinsel ve antioksidan değerleri sebebiyle araştırmalarda yer almıştır. Ellajik asit çilek, kızılcık, ceviz, nar ve ahududu gibi birçok meyvede bulunan doğal bir bileşiktir. Ellajik asit antioksidan özellikleri ile bilinen ve insan vücudunu zararlı serbest radikallerden koruyan bir bileşiktir. Bu çalışmada ellajik asit birçok kanser hücresi üzerinde hücre büyümesini baskılama özelliğinden dolayı akciğer kanseri A549 hücrelerinde hücre ölümünü tetiklemek amacıyla kullanılmıştır. A549 hücrelerine ellajik asidin sitotoksik etkilerini araştırmak için MTT (3-(4,5dimethylthiazol-2-yl)-2,5 diphenyl-2H-tetrazolium bromide) tekniği kullanılmıştır. Buna ilaveten ince yapısal ve morfolojik değişiklikler TEM ve konfokal mikroskopi teknikleri kullanılarak değerlendirilmiştir. Sitotoksisite test sonuçları uygulama dozunun artması ile hücre canlılığının düştüğünü göstermiştir ve morfolojik ve ince yapısal analizler bu ajanın sitotoksisitesini kromatin yoğunlaşması, membran tomurcuklanması, krista kaybı gibi apoptotik gösterge olarak değerlendirilen değişikliklere yol açarak gerçekleştirdiğini göstermiştir. Sonuçlarımıza dayanılarak ellajik asit farklı kanser hücrelerinde kanser tedavisinde alternatif bir tedavi ajanı geliştirmek amacıyla daha ileri araştırmalar için önerilmektedir. Anahtar Kelimeler-A549, ellajik asit, akciğer kanseri, TEM, konfokal.