Extracellular free amino acids contribute to the interaction between a tumor and its microenvironment through effects on cellular metabolism and malignant behavior. System xc(−) is composed of xCT and CD98hc subunits and functions as a plasma membrane antiporter for the uptake of extracellular cystine in exchange for intracellular glutamate. Here we show that the epidermal growth factor receptor (EGFR) interacts with xCT and thereby promotes its cell surface expression and function in human glioma cells. EGFR-expressing glioma cells manifested both enhanced antioxidant capacity as a result of increased cystine uptake as well as increased glutamate which promotes matrix invasion. Imaging mass spectrometry also revealed that brain tumors formed in mice by human glioma cells stably overexpressing EGFR contained higher levels of reduced glutathione compared with those formed by parental cells. Targeted inhibition of xCT suppressed the EGFR-dependent enhancement of antioxidant capacity in glioma cells as well as tumor growth and invasiveness. Our findings establish a new functional role for EGFR in promoting the malignant potential of glioma cells through interaction with xCT at the cell surface.

Many families have unfinished business. Health care professionals should coordinate the appropriate timing for what the family wishes to do, with consideration of family dynamics, including the family's preparedness, communication pattern, and relationships.

No abstract

Background: Mastery is a human response of gaining competence in dealing with stress and can be applied to understanding the psychological state of patients with advanced or recurrent colorectal cancer (CRC). Objective: To identify mastery in patients with advanced or recurrent CRC undergoing chemotherapy and examine associations between mastery and the patients’ sociodemographic characteristics, social support, and support from clinical staff. Methods: A self-administered survey was conducted among patients with advanced or recurrent CRC receiving outpatient chemotherapy. Participants completed the Mastery of Stress Instrument, the Multidimensional Scale of Perceived Social Support, support from clinical staff, and sociodemographic characteristics. Results: Of 76 participants, 77.6% had a stress score of ≥58 points, indicating a stress status. They achieved, in descending order, acceptance, certainty, change, and growth among mastery processes. Social support was significantly associated with mastery and all its components, and support from clinical staff was significantly associated with mastery and certainty. Conclusions: Most participants reported a high level of stress, indicating that they need support to deal with stress from a mastery perspective. Implications for Practice: Nurses should assess the stress levels of patients with advanced or recurrent CRC and provide care based on mastery to help patients come to terms with cancer-related stress. Providing emotional and social support is necessary to promote positive change and growth. Foundational: This study framed the need for nursing care for stressed patients in terms of their mastery of advanced or recurrent CRC-specific stress. Social support and clinical staff support are essential for achieving such mastery.