Warburg effect) is frequently associated with malignant tumors, in both hypoxic and normoxic cancer cells (76). targets, we show that apical delivery of CEA is not affected by hypoxia, ROS, nor changes in the Golgi NKSF2 redox state. Instead, we find that an elevated Golgi pH induces basolateral targeting of CEA and increases its TX-100 solubility, indicating impaired association of CEA with lipid rafts. Moreover, disruption of lipid rafts by methyl–cyclodextrin induced accumulation of the PI4KIIIbeta-IN-9 CEA protein at the basolateral surface in MDCK cells. Experiments with the glycosylphosphatidylinositol (GPI)-anchorless CEA mutant and CEA-specific GPI-anchored enhanced green fluorescent protein (EGFP-GPI) fusion protein revealed that the GPI-anchor was PI4KIIIbeta-IN-9 critical for the pH-dependent apical delivery of the CEA in MDCK cells. The findings indicate that an abnormal Golgi pH homeostasis in cancer cells is an important factor that causes mistargeting of CEA to the basolateral surface of cancer cells inhibiting its GPI-anchor-mediated association with lipid rafts. by staining normal and colorectal cancer tissue sections with the anti-CEA antibody (COL-1). As expected, the CEA protein localized exclusively at the apical surface in normal noncancerous acinar epithelial cells (Fig. 1A), that is, the plasma membrane facing the acinar lumen. By contrast, in cancer tissue specimens, CEA was detected at both the apical and basolateral cell surfaces (Fig. 1A). The insert in Figure 1A (right) shows staining of both the basolateral and apical membrane domains of the columnar epithelial cells. Open in a separate window FIG. 1. Localization of CEA in normal and cancer tissues as well as in cultured cells. (A) Colon tissue specimens cut longitudinally into 5-m sections were processed for immunostaining with the monoclonal anti-CEA antibody (COL-1) followed by peroxidase conjugated anti-mouse secondary antibody and DAB staining. Both normal (51%) PI4KIIIbeta-IN-9 of CEA in CaCo-2 cells were recovered from the apical and basolateral surfaces, respectively. Rebound Track This work was rejected during standard peer review and rescued by Rebound Peer Review (16: 293C296, 2012) with the following serving as open reviewers: Marc Fransen, Mary E. Choi, Kristian Prydz, and Michael Caplan. Marc Fransen (16: 293C296, 2012) and move to rescue this article that was rejected during the regular peer review process after reviewing all versions of the article and detailed reviewer comments. The manuscript authored by Kokkonen and coworkers is an interesting study aiming at understanding the molecular mechanisms underlying the mistargeting of carcinoembryonic antigen (CEA), a glycosylphosphatidylinositol (GPI)-anchored protein, to the basolateral surface in cancer cells. Given that hypoxia, altered redox state, and altered Golgi pH homeostasis are all hallmarks of tumorigenesis, the authors focused on these parameters. First, they established and validated a new experimental setup. Next, by employing various microscopic, cell biological, and biochemical approaches, they identified disturbances in Golgi luminal pH, but not hypoxia or Golgi redox state, as the causative factor for altered CEA localization. In addition, the authors also demonstrated that elevated Golgi pH impairs the association of CEA with membrane rafts, and that mistargeting of CEA to the basolateral membrane is not due to immature N-glycosylation, a pH-sensitive event. Together, these novel findings provide a molecular explanation for CEA mislocalization in cancer cells. Whether or not disturbances in Golgi pH also affect the targeting of other endogenous GPI-anchored membrane proteins remains to be established. However, given that CEA is an extensively studied molecule with proven functions in multiple cancer types, the manuscript is of broad interest to researchers in the field. As, in my opinion, (i) the authors have properly addressed all genuine comments and criticisms raised by the previous reviewers, and (ii) the key findings reported are novel, relevant, and sound, I fully support acceptance with the provision that the authors make the suggested editorial changes. Therefore, in the interest of science, I take full responsibility to rescue this work from rejection. Mary E. Choi (16: 293C296, 2012) and move to rescue this article that was rejected during the regular peer review process after reviewing all versions of the article and detailed reviewer comments. The manuscript by Kokkonen is an interesting study that examines the mechanism of the loss of polarity in colorectal cancer cells involving impaired apical targeting of CEA, known as a tumor marker for colorectal cancer with well-established functions in multiple cancer cell types. Loss of epithelial cell polarity is a key feature implicated in tumorigenesis, cancer cell migration, and metastasis and as such, the studies herein are of high significance.