Acute exposure to ionizing radiation can cause lethal damage to the gastrointestinal (GI) tract, a condition called the GI syndrome. Whether the target cells mediating the GI syndrome are derived from the epithelium or endothelium, and whether the target cells die by apoptosis or other mechanisms, are controversial issues. Studying mouse models, we found that selective deletion of the pro-apoptotic genes Bak1 and Bax from the GI epithelium or from endothelial cells did not protect mice from developing the GI syndrome after subtotal body gamma irradiation. In contrast, selective deletion of p53 from the GI epithelium, but not endothelial cells, sensitized irradiated mice to the GI syndrome. Transgenic mice overexpressing p53 in all tissues were protected from the GI syndrome after irradiation. These results suggest that the GI syndrome is caused by death of GI epithelial cells by a mechanism that is regulated by p53 but independent of apoptosis.

PURPOSE OF REVIEW Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of skin-homing T-cell neoplasms, which represent approximately 75% of all primary cutaneous lymphomas. Currently available drug therapies, when effective, simply control disease and the only option for curing CTCL is stem cell transplant. RECENT FINDINGS In the last year, there has been an incredible effort made to improve the understanding and treatment of CTCL. Recent findings indicate that epigenetic aberrations are integral to active disease. Furthermore, multiple tumor-derived immunological factors have also been shown to inhibit viability, proliferation, and cytokine production of nonmalignant T cells. Several novel targeted therapies show great potential, most promising being antibody drug conjugates targeting surface markers such as CD30 in some CTCL subtypes. Additional attractive targets involve the global modulation of epigenetic markers such as demethylation agents or HDAC inhibitors, either as single agents or in combination therapies. SUMMARY This is a concise review of recent advances in the field of CTCL with special focus on research articles over the preceding year. Purpose of review Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of skin-homing T-cell neoplasms, which represent approximately 75% of all primary cutaneous lymphomas. Currently available drug therapies, when effective, simply control disease and the only option for curing CTCL is stem cell transplant. Recent findingsIn the last year, there has been an incredible effort made to improve the understanding and treatment of CTCL. Recent findings indicate that epigenetic aberrations are integral to active disease. Furthermore, multiple tumor-derived immunological factors have also been shown to inhibit viability, proliferation, and cytokine production of nonmalignant T cells. Several novel targeted therapies show great potential, most promising being antibody drug conjugates targeting surface markers such as CD30 in some CTCL subtypes. Additional attractive targets involve the global modulation of epigenetic markers such as demethylation agents or HDAC inhibitors, either as single agents or in combination therapies. SummaryThis is a concise review of recent advances in the field of CTCL with special focus on research articles over the preceding year.

mtCLIC/CLIC4 is a p53 and tumor necrosis factor α (TNFα) regulated intracellular chloride channel protein that localizes to cytoplasm and organelles and induces apoptosis when overexpressed in several cell types of mouse and human origin. CLIC4 is elevated during TNFα-induced apoptosis in human osteosarcoma cell lines. In contrast, inhibition of NFκB results in an increase in TNFα-mediated apoptosis with a decrease in CLIC4 protein levels. Cell lines expressing an inducible CLIC4-antisense construct that also reduces the expression of several other chloride intracellular channel (CLIC) family proteins were established in the human osteosarcoma lines SaOS and U2OS cells and a malignant derivative of the mouse squamous papilloma line SP1. Reduction of CLIC family proteins by antisense expression caused apoptosis in these cells. Moreover, CLIC4-antisense induction increased TNFα-mediated apoptosis in both the SaOS and U2OS derivative cell lines without altering TNFα-induced NFκB activity. Reducing CLIC proteins in tumor grafts of SP1 cells expressing a tetracycline-regulated CLIC4-antisense substantially inhibited tumor growth and induced tumor apoptosis. Administration of TNFα i.p. modestly enhanced the antitumor effect of CLIC reduction in vivo. These results suggest that CLIC proteins could serve as drug targets for cancer therapy, and reduction of CLIC proteins could enhance the activity of other anticancer drugs.