UVB-induced Epidermal Growth Factor Receptor Phosphorylation is Critical for Downstream Signaling and Keratinocyte Survival ¶

How cells sense and integrate information from different sources

Cell signaling is a fundamental cellular process that enables cells to sense and respond to information in their surroundings. At the molecular level, signaling is primarily carried out by transmembrane protein receptors that can initiate complex downstream signal transduction cascades to alter cellular behavior. In the human body, different cells can be exposed to a wide variety of environmental conditions, and cells express diverse classes of receptors capable of sensing and integrating different signals. Furthermore, different receptors and signaling pathways can crosstalk with each other to calibrate the cellular response. Crosstalk occurs through multiple mechanisms at different levels of signaling pathways. In this review, we discuss how cells sense and integrate different chemical, mechanical, and spatial signals as well as the mechanisms of crosstalk between pathways. To illustrate these concepts, we use a few well-studied signaling pathways, including receptor tyrosine kinases and integrin receptors. Finally, we discuss the implications of dysregulated cellular sensing on driving diseases such as cancer. This article is categorized under: Cancer > Molecular and Cellular Physiology Metabolic Diseases > Molecular and Cellular Physiology.

Complications following novel therapies for non-small cell lung cancer

The emergence of tyrosine kinase inhibitors and immune checkpoint inhibitors has paved a new era for the management of non-small cell lung cancer, which has for many years lacked major clinical breakthroughs. Historically, 5-year overall survival remained below 5% in individuals with metastatic disease. These novel treatments have led to significant prolongation of survival in the locally advanced and metastatic setting, exceeding 25% in selected populations. However, they present new challenges to clinicians due to their inherently different spectrum of toxicity unique to each specific drug's pharmacodynamic profile. Internists commonly come across these side effects in their daily clinical practice. Their optimal recognition and management are of utmost importance, because it is associated with significant improvements in patient survival outcomes and their quality of life. The aim of this review is to summarize the complications following these novel treatments for non-small cell lung cancer.

p53 tumor suppressor gene: a critical molecular target for UV induction and prevention of skin cancer

The relationship between exposure to UV radiation and development of skin cancer has been well established. Several studies have shown that UVB induces unique mutations (C-->T and CC-->TT transitions) in the p53 tumor suppressor gene that are not commonly induced by other carcinogens. Our studies have demonstrated that UV-induced mouse skin cancers contain p53 mutations at a high frequency and that these mutations can be detected in UV-irradiated mouse skin well before the appearance of skin tumors. This observation suggested that it might be possible to use p53 mutations as a biologic endpoint for testing the efficacy of sunscreens in photoprotection studies. Indeed, application of SPF 15 sunscreens to mouse skin before each UVB irradiation resulted in reduction in the number of p53 mutations. Because p53 mutations represent an early essential step in photocarcinogenesis, these results imply that inhibition of this event may protect against skin cancer development. This hypothesis was confirmed by our finding that sunscreens used in p53 mutation inhibition experiments also protected mice against UVB-induced skin cancer.