Radiation therapy is one of the major tools of cancer treatment, and is widely used for a variety of malignant tumours. Radiotherapy causes DNA damage directly by ionization or indirectly via the generation of reactive oxygen species (ROS), thereby destroying cancer cells. However, ionizing radiation (IR) paradoxically promotes metastasis and invasion of cancer cells by inducing the epithelial-mesenchymal transition (EMT). Metastasis is a major obstacle to successful cancer therapy, and is closely linked to the rates of morbidity and mortality of many cancers. ROS have been shown to play important roles in mediating the biological effects of IR. ROS have been implicated in IR-induced EMT, via activation of several EMT transcription factors—including Snail, HIF-1, ZEB1, and STAT3—that are activated by signalling pathways, including those of TGF-β, Wnt, Hedgehog, Notch, G-CSF, EGFR/PI3K/Akt, and MAPK. Cancer cells that undergo EMT have been shown to acquire stemness and undergo metabolic changes, although these points are debated. IR is known to induce cancer stem cell (CSC) properties, including dedifferentiation and self-renewal, and to promote oncogenic metabolism by activating these EMT-inducing pathways. Much accumulated evidence has shown that metabolic alterations in cancer cells are closely associated with the EMT and CSC phenotypes; specifically, the IR-induced oncogenic metabolism seems to be required for acquisition of the EMT and CSC phenotypes. IR can also elicit various changes in the tumour microenvironment (TME) that may affect invasion and metastasis. EMT, CSC, and oncogenic metabolism are involved in radioresistance; targeting them may improve the efficacy of radiotherapy, preventing tumour recurrence and metastasis. This study focuses on the molecular mechanisms of IR-induced EMT, CSCs, oncogenic metabolism, and alterations in the TME. We discuss how IR-induced EMT/CSC/oncogenic metabolism may promote resistance to radiotherapy; we also review efforts to develop therapeutic approaches to eliminate these IR-induced adverse effects.

A s dielectric structures with a submicrometer length scale can interact strongly with light, various remarkable optical responses can be designed and tailored depending on the types and parameters of their structures. Over the past few decades, the unusual optical properties of the periodic dielectric structures called photonic crystals have been investigated intensively [1]. Many research groups have endeavored to engineer the optical properties of photonic crystals, including photonic bandgaps, 'slow' photons, negative refraction and other properties, or to use them in practical applications. Two-dimensional (2D) structures, which are mostly prepared by conventional lithographic processes, were demonstrated initially, in which total internal refl ections were adopted for confi ning the light in a nonperiodic third direction, and their use has been investigated in some limited applications [2]. Th ree-dimensional (3D) structures have also been investigated intensively because of their complete photonic bandgaps in certain structures, a critical property for controlling light in 3D space. Research on such structures has been supported by the recent development of facile fabrication methods, including the selfassembly of simple monodisperse particles, also known as colloidal self-assembly [3], block copolymer self-assembly [4], the auto-cloning process [5] and holographic lithography [6]. Of these methods, colloidal self-assembly is the most promising for the low-cost production of 2D and 3D photonic crystals over large areas or with various shapes [7,8]. Schematic diagrams of the basic colloidal crystal structure along with inverse and short-range-ordered scattering structures for photonic applications are shown in Figure 1. Disordered dielectric structures of monodisperse particles called photonic glasses have begun to be investigated as another class of photonic nanostructures that can manifest some unusual optical phenomena such as random lasing, strong light localization and long-range intensity correlations. In this review article, we describe self-assembled colloidal photonic nanostructures in brief and summarize recent achievements in the fi eld of colloidal photonic nanostructures and their applications. Fabrication of photonic nanostructures by colloidal assembly Colloidal crystalsSince Vanderhoff 's serendipitous discovery of a synthetic method for preparing monodisperse polymer colloids [9], the method has been extended to the preparation of a variety of polymeric colloids and also to the processing of inorganic colloidal particles such as silica, titania and iron oxide. As long as particles are stable in liquid and their size distribution is suffi ciently narrow, they can be crystallized in a facecentered cubic (fcc) lattice by increasing their volume fraction through any concentration process, such as controlled evaporation, sedimentation or fi ltration. In general, the interparticle forces can be described by summing over the various potentials from diff erent origins, including intermolecular for...

In this paper we discuss the transformation of a sheet of material into a wide range of desired shapes and patterns by introducing a set of simple cuts in a multilevel hierarchy with different motifs. Each choice of hierarchical cut motif and cut level allows the material to expand into a unique structure with a unique set of properties. We can reverse-engineer the desired expanded geometries to find the requisite cut pattern to produce it without changing the physical properties of the initial material. The concept was experimentally realized and applied to create an electrode that expands to >800% the original area with only very minor stretching of the underlying material. The generality of our approach greatly expands the design space for materials so that they can be tuned for diverse applications.he physical properties of materials are largely determined by structure: atomic/molecular structure, phase distribution, internal defects, nano/microstructure, sample geometry, and electronic structure. Among these, engineering the geometry of the sample can provide a direct, intuitive, and often materialindependent approach to achieve a predetermined set of properties. Metamaterials are fabricated based on geometric concepts (1-16). In two dimensions, periodic geometries have been adopted to tune the mechanical properties of membranes (3-8, 10, 12-14). From simple shapes such as circles (3), triangles (6,7,12,13), and quadralaterals (4, 5, 14) to more complex shapes (8, 10), a broad range of mechanical behavior has been observed, including pattern transformation, negative Poisson's ratio (auxetic), elastic response, and isostaticity. Origami and kirigami, the arts of paper folding and paper cutting, create beautiful patterns and shapes that have attracted the attention of scientists to two-dimensional materials (e.g., graphene, polymer films, and so on) (11,(17)(18)(19). However, application of conventional origami and kirigami approaches to achieve desired material response requires complex cutting and/or folding patterns that are often incompatible with engineering materials. In this paper we propose an advanced approach to the design of two-dimensional structures that can achieve a wide range of desirable programmed shapes and mechanical properties.This study starts from the question, Can we design twodimensional structures that can be formed by simply cutting a sheet, that can morph into a specific shape? In nature, many biological and natural system (20) can be found that use hierarchical structure to produce different properties and/or shapes. One such example is a stem cell. An embryonic, pluripotent stem cell can differentiate into any type of cell in the body (21). By recursively dividing, the stem cell can transform into particular cell types or remain unspecialized with the potential to transform. For a material, one aspect of recursive hierarchical geometry was recently discussed for applications in flexible electronics (22). Here, by analogy to the stem cell, we demonstrate that starting from a simpl...

Wnt signaling plays a critical role in embryonic development, and its deregulation is closely linked to the occurrence of a number of malignant tumors, including breast and colon cancer. The pathway also induces Snail-dependent epithelial-to-mesenchymal transition (EMT), which is responsible for tumor invasion and metastasis. In this study, we show that Wnt suppresses mitochondrial respiration and cytochrome C oxidase (COX)