Purpose: Incapacitating symptom burden in cancer patients contributes to poor quality of life (QOL) and can influence treatment outcomes because of poor tolerance to therapy. In this study, the role of circulating cytokines in the production symptoms in cancer patients is evaluated.Experimental Design: Eighty patients with metastatic colorectal cancer with either normal (group I, n = 40) or dampened (group II, n = 40) 24-hour rest/ /activity patterns measured by actigraphy were identified. Actigraphy patterns were correlated with QOL indices, serum cortisol obtained at 8:00 a.m. and 4:00 p.m. and with serum levels of transforming growth factor-A, tumor necrosis factor-A, and interleukin 6 (IL-6) obtained at 8:00 a.m. and analyzed in duplicate by ELISA. Cytokine levels and survival were also correlated.Results: Group II patients had significantly higher pre treatment levels of all three cytokines, displayed significantly poorer emotional and social functioning, had higher fatigue, more appetite loss, and poorer performance status compared with group I patients. Transforming growth factor-A (TGF-A) and IL-6 were significantly increased in the patients with WHO performance status >1 and in those with appetite loss. Fatigue was significantly associated with elevated TGF-A only. IL-6 was increased in those patients with extensive liver involvement and multiple organ replacement, and it was significantly correlated with dampened cortisol rhythm. In a multivariate analysis, IL-6 was correlated with poor treatment outcome.Conclusions: Significant correlations were found between serum levels of TGF-A and IL-6, circadian patterns in wrist activity and serum cortisol and tumor-related symptoms in patients with metastatic colorectal cancer. These data support the hypothesis that some cancer patient's symptoms of fatigue, poor QOL, and treatment outcome are related to tumor or host generated cytokines and could reflect cytokine effects on the circadian timing system. This interplay between cytokine signaling pathways, the hypothalamicpituitary-adrenal axis, the autonomic nervous system, and efferent pathways of the suprachiasmatic nucleus that control circadian physiology, opens the way to new rational interventions for symptom management in cancer patients.

When co-overexpressed, the epidermal growth factor receptor (EGFR) and c-Src cooperate to cause synergistic increases in EGF-induced DNA synthesis, soft agar colony growth, and tumor formation in nude mice. This synergy is dependent upon c-Src-mediated phosphorylation of a unique tyrosine on the EGFR, namely, tyrosine 845 (Y845). Phenylalanine substitution of Y845 (Y845F) was found to inhibit EGF-induced DNA synthesis without affecting the catalytic activity of the receptor or its ability to phosphorylate Shc or activate mitogen-activated protein kinase. These results suggest that synergism may occur through alternate signaling pathways mediated by phosphorylated Y845 (pY845). One such pathway involves the transcription factor Stat5b. Here we describe another pathway that involves cytochrome c oxidase subunit II (CoxII). CoxII was identified as a specific binding partner of a pY845-containing peptide in a phage display screen. EGFdependent binding of CoxII to the wild type but not to the mutant Y845F-EGFR was confirmed by coimmunoprecipitation experiments. This association also required the kinase activity of c-Src. Confocal microscopy, as well as biochemical fractionation, indicated that the EGFR translocates to the mitochondria after EGF stimulation, where it colocalizes with CoxII. Such translocation required the catalytic activity of the receptor but not phosphorylation of Y845. However, ectopic expression of the Y845F-EGFR prevented the EGF from protecting MDA-MB-231 breast cancer cells from adriamycin-induced apoptosis, whereas two mutants of Stat5b, a dominant-interfering mutant (DNstat5b) and a tyrosine mutation at 699 (Y699F-Stat5b) did not. Taken together, these data suggest that, through the ability of EGFR to translocate to the mitochondria, the binding of proteins such as CoxII to pY845 on the EGFR may positively regulate survival pathways that contribute to oncogenesis.The epidermal growth factor receptor (EGFR) is a critical regulator of many normal cellular processes, including cell growth, differentiation, survival, and migration. The EGFR also is implicated in pathological processes of cellular transformation and oncogenesis due to its overexpression in many types of cancers (including 20 to 30% of all breast cancers) (2) and its ability to induce morphological transformation of cultured cells and tumor formation in nude mice (11, 37). Many different signaling pathways have been discovered to mediate the effects of EGF, the most notable being Ras-mitogen-activated protein kinase (MAPK) and the phosphatidylinositol 3-kinase pathways (reviewed in reference 9). In these pathways EGF binds to the EGFR to induce dimerization, catalytic activation, and autophosphorylation of tyrosines in the C-terminal tail of the EGFR. These phosphorylated tyrosines provide docking sites for adapter proteins such as Grb2, Shc, and Gab2 to link the receptor to the Ras-MAPK, as well as phosphatidylinositol 3-kinase pathways. Interestingly, activation of both pathways has been implicated in both normal and pathological...

Co-overexpression of the epidermal growth factor (EGF) receptor (EGFR) and c-Src frequently occurs in human tumorsand is linked to enhanced tumor growth. In experimental systems this synergistic growth requires EGF-dependent association of c-Src with the EGFR and phosphorylation of Tyr-845 of the receptor by c-Src. A search for signaling mediators of Tyr(P)-845 revealed that mitochondrial cytochrome c oxidase subunit II (CoxII) binds EGFR in a Tyr(P)-845-and EGF-dependent manner. In cells this association involves translocation of EGFR to the mitochondria, but regulation of this process is ill-defined. The current study demonstrates that c-Src translocates to the mitochondria with similar kinetics as EGFR and that the catalytic activity of EGFR and c-Src as well as endocytosis and a mitochondrial localization signal are required for these events. CoxII can be phosphorylated by EGFR and c-Src, and EGF stimulation reduces Cox activity and cellular ATP, an event that is dependent in large part on EGFR localized to the mitochondria. These findings suggest EGFR plays a novel role in modulating mitochondrial function via its association with, and modification of CoxII. The epidermal growth factor receptor (EGFR)2 is overexpressed in many cancers including breast cancers, where its overexpression is associated with a poor prognosis (1, 2), yet EGFR alone when overexpressed in fibroblasts is a weak oncogene (3). The non-receptor-tyrosine kinase, c-Src, is also overexpressed in ϳ70% of breast cancers (4), suggesting that EGFR and c-Src may function cooperatively in cancers that co-overexpress both kinases (1). Investigations in murine fibroblasts and in human breast cancer cells have revealed synergistic increases in DNA synthesis, soft agar colony growth, and tumor formation in nude mice when EGFR and c-Src are co-overexpressed as compared with cells overexpressing EGFR or c-Src alone (5, 6). These synergistic increases are dependent upon EGF stimulation, the kinase activity of c-Src, and c-Src phosphorylation of tyrosine 845 (Tyr-845) (7), a highly conserved residue in the activation loop of the catalytic domain of the EGFR. Substitution of a phenylalanine for a tyrosine at position 845 (Y845F) ablates EGF-induced DNA synthesis (even in the presence of overexpressed c-Src) without affecting the intrinsic kinase activity of the EGFR or its ability to phosphorylate canonical downstream substrates (13). Combined, these results suggest that phosphorylated Tyr-845 (Tyr(P)-845) elicits a critical mitogenic signal when EGFR and c-Src are co-overexpressed that is mediated through unconventional substrates.Subsequent efforts to identify mediators of the Tyr(P)-845 EGFR mitogenic signal revealed that phosphorylation and transcriptional activation of Stat5b are dependent on Tyr(P)-845 and that Stat5b is required for EGF-induced DNA synthesis (8). Phage display screening of a human breast cancer tissue library also identified cytochrome c oxidase subunit II (CoxII) as a protein that binds the EGFR in a Tyr(P)-845-and EGF-dependent...