Phytochemicals as Regulators of Tumor Glycolysis and Hypoxia Signaling Pathways: Evidence from In Vitro Studies.

The full understanding of the complex nature of cancer still faces many challenges, as cancers arise not as a result of a single target disruption but rather involving successive genetic and epigenetic alterations leading to multiple altered metabolic pathways. In this light, the need for a multitargeted, safe and effective therapy becomes essential. Substantial experimental evidence upholds the potential of plant-derived compounds to interfere in several important pathways, such as tumor glycolysis and the upstream regulating mechanisms of hypoxia. Herein, we present a comprehensive overview of the natural compounds which demonstrated, in vitro studies, an effective anticancer activity by affecting key regulators of the glycolytic pathway such as glucose transporters, hexokinases, phosphofructokinase, pyruvate kinase or lactate dehydrogenase. Moreover, we assessed how phytochemicals could interfere in HIF-1 synthesis, stabilization, accumulation, and transactivation, emphasizing PI3K/Akt/mTOR and MAPK/ERK pathways as important signaling cascades in HIF-1 activation. Special consideration was given to cell culture-based metabolomics as one of the most sensitive, accurate, and comprising approaches for understanding the response of cancer cell metabolome to phytochemicals.

From Extraction to Advanced Analytical Methods: The Challenges of Melanin Analysis.

The generic term "melanin" describes a black pigment of biological origin, although some melanins can be brown or even yellow. The pigment is characterized as a heterogenic polymer of phenolic or indolic nature, and the classification of eu-, pheo- and allo- melanin is broadly accepted. This classification is based on the chemical composition of the monomer subunit structure of the pigment. Due to the high heterogeneity of melanins, their analytical characterization can be a challenging task. In the present work, we synthesized the current information about the analytical methods which can be applied in melanin analysis workflow, from extraction and purification to high-throughput methods, such as matrix-assisted laser desorption/ionization mass-spectrometry or pyrolysis gas chromatography. Our thorough comparative evaluation of analytical data published so far on melanin analysis has proven to be a difficult task in terms of finding equivalent results, even when the same matrix was used. Moreover, we emphasize the importance of prior knowledge of melanin types and properties in order to select a valid experimental design using analytical methods that are able to deliver reliable results and draw consistent conclusions.

Concepts and Challenges of Biosimilars in Breast Cancer: The Emergence of Trastuzumab Biosimilars.

With the development of anti-human epidermal growth factor receptor 2 (HER2) monoclonal antibodies, trastuzumab-based therapy has become the standard of care among patients with early or advanced HER2-positive breast cancer. However, real-world data have shown that up to a half of patients do not receive trastuzumab or any other HER2-targeted agent, mainly due to high treatments costs. The prospect of a more enlarged access to trastuzumab treatment lies in the use of biosimilars, as the European and the US patent of the reference products has or will soon expire. Biosimilars are biologics highly similar in terms of quality characteristics, biological activity, safety and efficacy to already approved biologics. The biosimilarity of any European Union (EU)-approved biosimilar is guaranteed based on the comprehensive comparability exercise which includes comparative analytical, non-clinical and clinical studies. In the matter of biosimilars' interchangeability and substitution, the European Medicines Agency (EMA) and US Food and Drug Administration (FDA) have adopted different positions, triggering various discussions on the potential immunogenicity and efficacy in individual patients. As more biosimilars are gaining approval, the present review aims to offer concise information for oncologists and pharmacists about the production, approval, interchangeability, and substitution policies of biosimilars used in breast cancer therapy, with a special focus on trastuzumab.