Dilek Göktürk

L-asparaginase (L-ASNase) is an enzyme that depletes asparagine, a key amino acid for cancer cell survival, producing aspartic acid and ammonia. Beyond its food industry applications, L-ASNase is a clinically important agent against acute lymphoblastic leukemia (ALL). In this study, L-ASNase was produced and purified from Candida utilis via solid-state fermentation. Optimization on wheat bran identified 2 mL inoculation volume, 60% moisture, and a 4-day fermentation period as the optimal conditions, yielding 172.5 U/mL activity. The purified enzyme was tested against glioblastoma (GBM) cell lines, showing IC₅₀ values of 0.4 U/mL for U87MG and 1.8 U/mL for T98G, with minimal toxicity toward normal HaCaT cells. Apoptotic effects were confirmed by DAPI/F-actin and Giemsa staining, while wound healing and clonogenic assays revealed inhibition of cell migration and colony formation. RT-qPCR analysis demonstrated downregulation of the Survivin gene, a key survival regulator. These findings highlight L-ASNase’s potent antiproliferative, anti-migratory, and pro-apoptotic effects, underscoring its potential as an adjuvant therapy for GBM.

Introduction: This study aimed to investigate the anti-carcinogenic effects of recombinant L- methioninase (rBlmet) on the pancreatic cancer cell line MiaPaCa-2. Methods: In this study, rBlmet was initially cloned, expressed, and purified. To increase enzyme activity, the His-tags on the enzyme were removed using thrombin. rBlmet was then applied to MiaPaCa- 2 cells, and the cell viability of MiaPaCa-2 cells was evaluated by neutral red assay after rBlmet treatment. The combined effect of etoposide with rBlmet against MiaPaCa-2 cells was also evaluated for 12 and 24 hours using a neutral red assay. Furthermore, cell morphology was evaluated by Giemsa and DAPI/F-actin staining methods. Survivin and caspase-3 gene expression levels were measured by RT-qPCR. Results and Discussion: The specific activity of the enzyme increased after His-tag elimination to 5.62 μmol/mg per minute. rBlmet showed a significant cytotoxic effect on the MiaPaCa-2 cell line. The IC50 value (24 h) of rBlmet for MiaPaCa-2 cells was 3.02 U/mL. In addition, rBlmet increased the cytotoxic effect of etoposide on the MiaPaCa-2 cell line, while it showed less effect on HaCat, which is a normal human cell line. Furthermore, rBlmet increased caspase-3 expression and downregulated survivin gene expression in MiaPaCa-2 cell lines. It successfully inhibited the growth of Mia-PaCa-2 cells by exploiting exogenous methionine amino acid in the growth medium. This study revealed promising results. However, further studies are needed on additional pancreatic cancer cell lines and in vivomodels. Conclusion: Based on these findings, it can be concluded that rBlmet not only has great potential to treat pancreatic cancer in the future but can also be used as an adjuvant to enhance the effectiveness of chemotherapeutic agents like etoposide.

Glucoamylase (1,4-α-glucosidase) is a crucial commercial enzyme responsible for the conversion of starch, glycogen, and oligosaccharides into D-glucose through the hydrolysis of their non-reducing terminal glycosidic bonds. While many microorganisms, including bacteria, yeasts, and fungi, can produce glucoamylase, fungal glucoamylase is the preferred choice for industrial applications. The goal of this study was to produce the glucoamylase enzyme recombinantly in Pichia pastoris. To achieve this, the glaA gene from Aspergillus niger, responsible for encoding the glucoamylase enzyme, was cloned into a plasmid (pGAPZα-A) under the control of the GAP promoter and subsequently transferred into P. pastoris. The gene was verified through sequence analysis, while the effectiveness of transfection was validated using colony PCR and enzyme activity assays. The results demonstrated that the recombinant P. pastoris strain successfully secreted a substantial amount of glucoamylase (307.05 mg/L). The activity of the recombinant enzyme was measured at 79 U/mL.min. The enzyme exhibited robust activity over a broad range of temperatures (50-80°C) and various pH levels (pH 5-10), retaining 92-60% of its maximum activity. In conclusion, this study highlights the potential for laboratory-scale production of the glucoamylase enzyme, crucial for various industries, from a cost-effective and easily cultivable recombinant yeast strain, P. pastoris.

Aims: Every year, a significant number of individuals lose their lives due to cancer or undergo challenging treatments. Indeed, the development of an effective cancer prediction method holds great importance in the field of healthcare. Methods: Machine learning methods have played a significant role in advancing cancer prediction models. In this context, this study focuses on exploring the potential of two machine learning methods: Artificial neural network (ANN) and adaptive-network-based fuzzy inference system (ANFIS) for cancer prediction. In this study, two different types of cancer, ovarian cancer and lung cancer, are taken into consideration. For the prediction of ovarian cancer, three specific biomarkers, namely human epididymis protein 4 (HE4), carbohydrate antigen 125 (CA-125), and carcinoembryonic antigen (CEA), are used to develop a prediction model. For the prediction of lung cancer, six different variables are utilized in the development of both the ANN and ANFIS methods. Results: The findings demonstrated that the proposed methods had an accuracy rate of at least 93.9% in predicting ovarian cancer. With an accuracy rate of at least 89%, the proposed methods predicted lung cancer. Also, the proposed ANN method outperforms the ANFIS method in terms of predictive accuracy for both ovarian cancer and lung cancer. Conclusion: This study suggests that the ANN method provides more reliable and accurate predictions for these specific cancer types based on the chosen variables or biomarkers. This study highlights the potential of machine learning methods, particularly ANN, in improving cancer prediction models and aiding in the early detection and effective management of ovarian and lung cancers.

Nutritional information on menus can assist customers in making healthier eating choices. One technique being utilized to tackle the rise of overweight and obesity is the use of nutritional information on menus. Menu engineering strategies can be used to improve sales of generally healthier and higher margin items. For today's food and beverage companies, menu engineering has become essential. Companies must continually evaluate their menus in order to keep up with changing customer demands and the conditions of the competitive market. Menu engineering's core involves comparing the effectiveness of each menu. At this point, correct decision-making under numerous factors is thought to be a very challenging procedure. To evaluate alternatives according to many features, several Multi-Criteria Decision-Making (MCDM) approaches have been created. The main novelty of this paper is that four MCDM methods, including Technique for Order Preference by Similarity to an Ideal Solution (TOPSIS), Fuzzy TOPSIS, VlseKriterijumska Optimizacija I Kompromisno Resenje (VIKOR), and Fuzzy VIKOR, are employed to evaluate menu options. Comparative analysis of MCDM methods is another contribution of this study. The process of evaluating and selecting healthier menu alternatives can become challenging and time-consuming. This study pointed out how crucial it is to conduct comparative analysis using various MCDA methods and to carefully determine the right ones when addressing the issue of selecting the best menu, taking into account the values of the criterion in fuzzy numbers.

L-methioninase degrades methionine, which is essential in methionine-dependent cancer cells, resulting in specific cell death. Normal cells can synthesize their own methionine amino acids even in the absence of exogenous methionine. This selective targeting of cancer cells makes L-methioninase a promising therapeutic candidate for cancer. In this study, L-methioninase was partially purified from Brevibacterium linens BL2. The specific activity of the enzyme was found as 3.055 units/mg. IC₅₀ values (24 h) of the enzyme were 5.792 units/mL for U87MG cell line and 5.215 units/mL for T98G cell line. When L-methioninase and etoposide were used in combination, synergistic cytotoxic and cell migration inhibition effects on U87MG and T98G cells alongside decreased cytotoxic activity on the Mouse Embryonic Fibroblast and HaCaT cells compared to etoposide alone were observed. Additionally, colony numbers of U87MG cells were significantly reduced by L-methioninase and etoposide administration after 21 days of incubation. Furthermore, L-methioninase suppressed the expression levels of survivin and c-Myc while increasing the expression level of Caspase-3 in both glioblastoma cell lines. These effects were enhanced when etoposide was used in combination with etoposide. This investigation reveals that the L-methioninase enzyme not only exhibited cytotoxic effects on U87MG and T98G cells but also enhanced the anti-proliferative effects of etoposide when used in combination while also demonstrating fewer adverse effects on normal cells.

Amaç: Bu çalışmada, glioblastoma hücre hattında (U87) siklopamin ve temozolomid (TMZ) tedavisinin ayrı ayrı ve kombine olarak uygulanmasından sonra miR-20a ekspresyonunun araştırılması ve bu miRNA’nın glioblastoma tedavisindeki etkinliğinin değerlendirilmesi amaçlanmıştır. Gereç ve Yöntem: U87 MG, tedaviden önce 35 mm'lik kültür kabı üzerine yerleştirildi ve çoğaltıldı. Çalışma kapsamında 7 grup oluşturuldu: Grup 1: Kontrol grubu, Grup 2: Sham grubu (Dimetil sülfoksit), Grup 3: 2 Gün TMZ, Grup 4: 5 Gün TMZ, Grup 5: 3 saat siklopamin, Grup 6: 2 Gün TMZ + 3 saat siklopamin, Grup 7: 5 Gün TMZ + 3 saat siklopamin. Tedaviden sonra total miRNA izolasyonu ve qRT-PCR yapıldı. Bulgular: Glioblastoma hücre hattında miR-20a ekspresyonunun grup 3, grup 4, grup 5, grup 6 ve grup 7’de belirgin olarak azaldığı tespit edildi. Ancak bu azalmanın en fazla grup 7 de olduğu saptandı . Ek olarak grup 7’de hücre sayısının azaldığı görüldü. Sonuç: Glioblastoma hücrelerinde miR-20a’nın yüksek oranda eksprese olduğu; ancak siklopamin ve TMZ tedavilerinden sonra ekspresyonun azaldığı tespit edildi. miR-20a’nın glioblastoma için yeni bir terapötik hedef ve biyobelirteç olarak kullanılabileceği, siklopamin ve TMZ’nin glioblastomada tedavi amaçlı kullanılabileceği ancak bu konuda daha ileri çalışmaların yapılması gerektiği sonucuna varıldı.