Sin-Yeang Teow

By Sin-Yeang Teow and Suat-Cheng Peh

Exosomes are microvesicles with sizes ranging from 50 to 150 nm. These small vesicles are known to morphologically and functionally resemble virus particles from human immunodeficiency virus type I (HIV-I) and human T-lymphotropic virus type I (HTLV-I). The function of exosomes is to mainly mediate cell-to-cell communication by exchanging various macromolecules including proteins, lipids and nucleic acids in diverse cellular processes. Due to its size and structural simplicity, the transfer of pathogenic or virulent cellular factors across the cells mediated by exosomes is more efficient, hence facilitating the dissemination of viral infections and cancer diseases. The pathogenic role of exosomes in various cancers such as lung and breast, and their potentials as biomarkers have been previously studied, yet limited information is known for Epstein-Barr virus (EBV)-associated cancers. In this chapter, we discuss current evidences that support the pathogenic roles of exosomes in EBV-related cancers and their potentials as biomarkers in cancer diagnostics and therapy response. Here, we also highlight the potential challenges in the development of exosome-based biomarkers for clinical application.

Part of the book: Novel Implications of Exosomes in Diagnosis and Treatment of Cancer and Infectious Diseases

By Jactty Chew, Suat-Cheng Peh and Teow Sin Yeang

Drug resistance developed in human pathogenic bacteria is emerging and has become a global problem. Methicillin-resistant Staphylococcus aureus (MRSA) spreading in both hospital and community areas has posed a great impact to global public health. Current antibiotics used against these resistant strains are no longer efficacious and the search for new alternative is in urgent need. In the past decades, natural products have demonstrated multiple biological activities in biomedical areas including their antibacterial actions against various drug-resistant bacteria. More promisingly, some natural products could reverse the resistance of bacteria to the antibiotics, making the target bacteria susceptible to these drugs again. Numerous natural products have also exhibited potent synergism against the drug-resistant bacteria when used in combination with various types of antibiotics. Recently, several antibacterials derived from microbes have been developed and approved by Food and Drug Administration (FDA) for clinical use. In this chapter, we discuss the potential use of non-microbial natural products in controlling Staphylococcus aureus (S. aureus)‘s growth, and the underlying challenges in developing the natural products into clinical applications.

Part of the book: Staphylococcus Aureus

By Siew-Wai Pang, Noel Jacques Awi, Hooi-Yeen Yap and Sin-Yeang Teow

Autophagy is a cellular mechanism that degrades damaged organelles and misfolded proteins to maintain cellular homeostasis. Autophagy in cancers is drawing increasing attentions due to its multifaceted roles in cancer development, progression, and treatment. There are several key autophagy effectors that are being extensively studied to understand the role of autophagy in cancer as well as their potential value as predictive and/or prognostic biomarkers and therapeutic target. These include ATG4A, ATG4B, Beclin-I, p62, LC3A, LC3B, LC3C, and LAMP. While having its own sophisticated pathway, autophagy has been reported to associate with multiple oncogenic pathways such as NF-kB, mTOR, and PI3K signaling. This chapter aims to provide a detailed protocol for researchers to investigate the role of autophagy using in vitro cell line as model. Here, we demonstrate several techniques including Western blot (WB), immunofluorescence (IF), and small-interfering RNA (siRNA) knockdown using colorectal cancer cell lines as samples. This chapter provides information to researchers especially those in their early- and mid-career to plan and design their experiments to study the autophagy events in their area of interests.

Part of the book: Cell Culture