In Vivo Models for Studying Hypoxic Cancer

Solid tumors are caused by the fast growth of cancer cells and inadequate vasculature, leading to nutrition and oxygen deprivation. This can cause a poorer prognosis for patients and can be replicated in vitro using 3D models of spheroids or organoids. Techniques to monitor O 2 concentrations are growing due to the clinical significance of hypoxia in cancer development. Optical and electrochemical probes can be used to test O 2 levels directly, while noninvasive methods like immunolabeling endogenous or exogenous markers have been refined. The hypoxia visualization platform accurately depicted hypoxia levels in vivo . Tumor hypoxia is associated with aggressiveness, resistance to chemotherapy and radiation, and poor clinical prognosis. Magnetic resonance imaging and positron emission tomography ( PET ) are often the preferred approaches in medical imaging. Noninvasive imaging biomarkers like PET radiolabeled ligands are essential for patient selection and follow-up. Preclinical in vivo validation in suitable animal models is necessary before these treatments and biomarkers can be used in the therapeutic environment. Researchers have used fluorescent, phosphorescent, and luminous reporters to offer dynamic measurements of O 2 in living cells or tumors. Angiogenesis and hypoxia accompany the formation of solid tumors, and understanding the actual state of tissue hypoxia and angiogenesis during tumor progression is crucial for cancer treatment. A unique approach to long-term monitoring of angiogenesis and tumor hypoxia in cervical cancer was presented, using cervical cancer cell lines transfected with the luciferase reporter gene driven by hypoxia response elements. The primary techniques used to identify hypoxia in vivo cancer models are described in this chapter.