Pinar Obakan-Yerlikaya

By Elif Damla Arisan, Pinar Obakan-Yerlikaya, Ajda Coker-Gurkan and Narçin Palavan Unsal

Autophagy is fundamental, evolutionary conserved physiological process at molecular level which targets long-lived cytosolic proteins and organelles to be recycled through lysosomal degradation. Diminished autophagic activity caused cellular stress in many organisms following aging, and inhibition of autophagy in model organisms causes degenerative changes and pathologic diseases observed with high incidence ratio generally in older ages. Consequently the delayed senescence or increased longevity in model organisms often stimulate autophagy, and autophagy inhibition compromises anti-aging effects. The cytoprotective function of autophagy is presented in various human diseases such as lung, liver, cardiovascular diseases, neurodegeneration, myopathies, cancer, stroke, infections and metabolic diseases which are found associated with autophagic targets. These pathologies are defined with their age-dependent characteristics, is not fully understood that how autophagy network regulates metabolism and may cause diseases in age-related manner. In this book chapter, we are going to discuss the autophagy and aging relationship in three different parts. In the first section autophagy and aging relationship is going to be presented through explaining responsible signalling network. The autophagy and age-related neurological disorders, genetic basis of age-dependent diseases and the functional role of autophagy is going to be discussed in the second and third part of the chapter.

Part of the book: Autophagy in Current Trends in Cellular Physiology and Pathology

By Pinar Obakan-Yerlikaya, Elif Damla Arisan, Ajda Coker-Gurkan and Narcin Palavan-Unsal

Breast cancer is the most prevalent cancer type among women. Despite recent progress in early detection and therapeutic strategies, the rate of mortality is increasing. Anti-estrogens or aromatase inhibitors are preferred to treat the women diagnosed with estrogen-receptor (ER) positive tumors. However, breast tumors usually show intra-tumoral heterogeneity with ER-positive and -negative cells. The advanced breast cancer cells lose the estrogen responsiveness and become aggressive by developing new strategies for rapid proliferation such as mutations in cell cycle machinery. New promising drugs are still being investigating against these types of tumors especially to overcome acquired resistance against chemotherapeutic drugs; however, a successful treatment for metastatic tumors is still unclear. Flavonoids, with various pharmacological activities, are plant or fungus secondary metabolites present in human diet. In plants, beside their role in pigmentation, they may also act as messengers, regulators and cell cycle inhibitors. Therefore, they are being tested in ovarian, cervical as well as breast cancer. Due to the positive correlation between flavonoids-rich diet and lower risk of cancer, flavonoids are referred as chemopreventive agents. The current chapter emphasizes the therapeutic potential of flavonoids and their synthetic analogues as anti-cancer agents in breast cancer providing new insights into the molecular mechanisms.

Part of the book: Breast Cancer

By Ajda Coker-Gurkan, Pinar Obakan-Yerlikaya and Elif-Damla Arisan

Aptamers are small and specific oligonucleotides [RNA or single-strand DNA (ssDNA)] with a high binding affinity against target protein. In vitro selection process of aptamer by selective evolution of ligands by exponential enrichment (SELEX) has been invented in 1990 by Larry Gold and Jack Szostak. SELEX is a random amplification of target protein with combined oligonucleotide libraries and selection of synthesized aptamer by magnetic beads, affinity chromatography, and capillary electrophoresis-based methods. According to their low molecular weight, non-immunogenic feature in vivo, low production cost, high thermal stability, increase in production potential, and ample of modification capacities, aptamers are becoming essential medical tools for diagnosis and treatment of diseases such as macular degeneration, hemophilia, heart disease, and various cancer types. The therapeutic potential of aptamers, with high binding affinity against carcinogenesis-associated growth factors, receptors, or proteins frequently overexpressed in specific cancers such as prostate, breast, colon, lung, leukemia, hepatocellular, and cervical carcinoma. The strategies for aptamer-based drugs in cancer therapy design/modify aptamers against cancer biomarkers, accelerate immunotherapy targeting immune system, and increase the drug delivery in cancer cells. In conclusion, aptamers are promising candidate drugs due to their antiproliferative effect on cancer cells and the drug delivery systems during cancer chemotherapy.

Part of the book: Cancer Management and Therapy