Cancer surveillance imaging: Does repeated iodinated contrast exposure impact long-term kidney function?

BACKGROUND: Contrast-induced nephropathy is a well-recognized acute complication in cancer patients, but the long-term effects of repeated contrast exposure are not known. We analyzed the association of the number of contrast-enhanced computed tomography (CECT) examinations and other clinical factors with decline in estimated glomerular filtration rate (eGFR) in colorectal cancer survivors. MATERIALS AND METHODS: We retrospectively queried a prospective surgical colorectal cancer database to identify patients with stage I or II cancer who underwent resection in 2007 - 2013 and were alive for at least 3 years. eGFR was calculated before and 3 years after the surgery with ≥ 20% decline relative to baseline defined as significant and used as the primary outcome. The association of clinical factors with the primary outcome was analyzed using logistic regression. RESULTS: Only 256 patients with the median follow-up of 65 months had sufficient clinical data for analysis. Median eGFR decline at follow-up was 3.0 mL/min/1.73m2 or 4% change from baseline. 47 patients (18%) had ≥ 20% reduction in eGFR, which was not associated with the number of CECT examinations. Multivariable analysis demonstrated that increasing age (OR, 1.03; 95% CI, 1.00 - 1.06), presence of diabetes (OR, 2.33; 95% CI, 1.18 - 4.61), and longer operation time (OR, 1.04; 95% CI, 1.01 - 1.07) were independently associated with a higher likelihood of ≥ 20% eGFR decline at 3 years. CONCLUSION: Older age, diabetes, and longer operating time, but not cumulative contrast exposure were found to be associated with worse long-term renal outcomes following surgical resection in patients with early-stage colorectal cancer who survived 3 years.

Dual Targeting of Protein Degradation Pathways with the Selective HDAC6 Inhibitor ACY-1215 and Bortezomib Is Synergistic in Lymphoma.

PURPOSE: Pan-class histone deacetylase (HDAC) inhibitors are effective treatments for select lymphomas. Isoform-selective HDAC inhibitors are emerging as potentially more targeted agents. HDAC6 is a class IIb deacetylase that facilitates misfolded protein transport to the aggresome for degradation. We investigated the mechanism and therapeutic impact of the selective HDAC6 inhibitor ACY-1215 alone and in combination with bortezomib in preclinical models of lymphoma. EXPERIMENTAL DESIGN: Concentration-effect relationships were defined for ACY-1215 across 16 lymphoma cell lines and for synergy with bortezomib. Mechanism was interrogated by immunoblot and flow cytometry. An in vivo xenograft model of DLBCL was used to confirm in vitro findings. A collection of primary lymphoma samples were surveyed for markers of the unfolded protein response (UPR). RESULTS: Concentration-effect relationships defined maximal cytotoxicity at 48 hours with IC50 values ranging from 0.9 to 4.7 µmol/L. Strong synergy was observed in combination with bortezomib. Treatment with ACY-1215 led to inhibition of the aggresome evidenced by acetylated α-tubulin and accumulated polyubiquitinated proteins and upregulation of the UPR. All pharmacodynamic effects were enhanced with the addition of bortezomib. Findings were validated in vivo where mice treated with the combination demonstrated significant tumor growth delay and prolonged overall survival. Evaluation of a collection of primary lymphoma samples for markers of the UPR revealed increased HDAC6, GRP78, and XBP-1 expression as compared with reactive lymphoid tissue. CONCLUSIONS: These data are the first results to demonstrate that dual targeting of protein degradation pathways represents an innovative and rational approach for the treatment of lymphoma.

Phase behavior of amphiphilic diblock co-oligomers with nonionic and ionic hydrophilic groups.

The synthesis of a series of co-oligomer amphiphiles by RAFT and their self-assembly behavior in water is described. These novel amphiphiles, comprised of styrene, butyl acrylate, and alkyl hydrophobes together with ionic acrylic acid and nonionic hydroxyethylacrylate hydrophilic moieties and with a total degree of polymerization from 5 to 17, represent a new class of small-molecule surfactants that can be formed from the immense potential library of all polymerizable monomers. Examples of micellar solutions and discrete cubic, hexagonal, lamellar, and inverted hexagonal lyotropic phases, as well as vesicle dispersions and coexisting lamellar phases, are reported and characterized by small-angle scattering. The variation of self-assembly structure with co-oligomer composition, concentration, and solution conditions is interpreted by analogy with the surfactant packing parameter used for conventional small-molecule amphiphiles.

A Stat5b transgene is capable of inducing CD8+ lymphoblastic lymphoma in the absence of normal TCR/MHC signaling.

Stat5 proteins are critical signaling molecules activated by many cytokines. Within the immune system, Stat5 plays important roles related to the development of thymocytes and proliferation of T cells. Stat5 has been implicated in malignant transformation, and moreover, the activated tyrosine phosphorylated form of Stat5 is frequently observed in human lymphomas. We previously demonstrated the oncogenic potential of Stat5, with thymic lymphoblastic lymphomas developing in a significant proportion of transgenic (TG) mice overexpressing Stat5a or Stat5b in lymphocytes. In addition, immunization or expression of a T-cell receptor (TCR) transgene augmented the rate of tumor formation. Here, we investigate the mechanism of Stat5-mediated lymphomagenesis by exploring the contributions of major histocompatibility complex (MHC)/TCR and pre-TCR signals. We present data demonstrating that Stat5b TG mice unexpectedly develop CD8(+) lymphoma even in the absence of either pre-TCR signaling or normal thymic selection. Indeed, acceleration of Stat5b transgene-mediated lymphoma occurred on TCRalpha(-/-) and pre-TCRalpha(-/-) backgrounds. In light of these data, we propose a model in which alterations in T-cell development at the double-negative/double-positive (DN/DP) stages cooperate with cytokine-mediated pathways in immature thymocytes to give rise to lymphoblastic T-cell lymphomas in Stat5b TG mice.

The active site His-460 of human acyl-coenzyme A:cholesterol acyltransferase 1 resides in a hitherto undisclosed transmembrane domain.

Human acyl-coenzyme A:cholesterol acyltransferase 1 (hACAT1) esterifies cholesterol at the endoplasmic reticulum (ER). We had previously reported that hACAT1 contains seven transmembrane domains (TMD) (Lin, S., Cheng, D., Liu, M. S., Chen, J., and Chang, T. Y. (1999) J. Biol. Chem. 274, 23276-23285) and nine cysteines. The Cys near the N-terminal is located at the cytoplasm; the two cysteines near the C-terminal form a disulfide bond and are located in the ER lumen. The other six free cysteines are located in buried region(s) of the enzyme (Guo, Z.-Y., Chang, C. C. Y., Lu, X., Chen, J., Li, B.-L., and Chang, T.-Y. (2005) Biochemistry 44, 6537-6548). In the current study, we show that the conserved His-460 is a key active site residue for hACAT1. We next performed Cys-scanning mutagenesis within the region of amino acids 354-493, expressed these mutants in Chinese hamster ovary cells lacking ACAT1, and prepared microsomes from transfected cells. The microsomes are either left intact or permeabilized with detergent. The accessibility of the engineered cysteines of microsomal hACAT1 to various maleimide derivatives, including mPEG(5000)-maleimide (large, hydrophilic, and membrane-impermeant), N-ethylmaleimide, 4-acetamido-4'-maleimidylstilbene-2,2'-disulfonic acid (small, hydrophilic, and ER membrane-permeant), and N-phenylmaleimide (small, hydrophobic, and ER membrane-permeant), were monitored by Western blot analysis. The results led us to construct a revised, nine-TMD model, with the active site His-460 located within a hitherto undisclosed transmembrane domain, between Arg-443 and Tyr-462.