Isolation, characterization, and nuclease activity of biologically relevant chromium(V) complexes with monosaccharides and model diols. Likely intermediates in chromium-induced cancers. | Sigma-Aldrich
The stabilization of Cr(V) by biological 1,2-diolato ligands, including carbohydrates, glycoproteins, and sialic acid derivatives, is likely to play a crucial role in the genotoxicity of Cr(VI) and has also been implicated in the antidiabetic effect of Cr(III). Previously, such complexes have been observed by electron paramagnetic resonance (EPR) spectroscopy in living cells or animals, treated with carcinogenic Cr(VI), as well as in numerous model systems, but attempts to isolate them have been elusive. Recently, the first crystal structure of a Cr(V) complex with cis-1,2-cyclohexanediol (1, a close structural analogue of carbohydrates) has been reported. In this work, Cr(V) complexes of the general formula [Cr(V)OL2](-) [where LH2 = 1, cis-1,2-cyclopentanediol (2), D-glucose (3), D-mannose (4), D-galactose (5), and D-ribose (6)] have been isolated from light-catalyzed reactions of Cr(VI) (anhydrous Na2Cr2O7) with slight molar excesses of the corresponding ligands in N,N-dimethylformamide. The complexes were characterized by elemental analyses, electrospray mass spectrometry (ESMS), and EPR spectroscopy. Studies by electronic absorption spectroscopy have shown that the solids isolated from reactions of Cr(VI) with 3-6 contained mixtures of Cr(V) complexes (40-65 mol %) and Cr(III) species (probably complexes with oxidized ligands), while those from reactions with 1 and 2 were practically pure Cr(V). The first isolation of solids containing significant proportions of chromium(V) monosaccharide complexes led to the definitive assignment of their general formula ([Cr(V)OL2](-), based on ESMS), in agreement with the earlier EPR spectroscopic data. The first direct comparison of the decomposition rates of Cr(V) complexes with 1-6, made possible by isolation of the solids, have shown that the complexes with five-membered-ring ligands (2 and 6) are more stable at pH ∼ 7 compared with their six-membered-ring counterparts (1 and 3-5). This finding emphasizes the likely biological roles of chromium(V) pentose complexes, e.g., those with sugar residues of RNA, ATP, or NAD(P)H. Finally, the first direct evidence for the ability of these Cr(V) complexes to cause oxidative DNA damage in the absence of added reductants or oxidants has been obtained. These data support significant roles for chromium(V) 1,2-diolato complexes in the diverse biological activities of Cr(VI) and Cr(III).
Southern Illinois Healthcare Foundation Receives $38,000 Grant from Avon Breast Health Outreach Program for START NOW Breast Health Services Program
The Avon Breast Health Outreach Program has awarded a $38,000 one-year grant to the Southern Illinois Healthcare Foundation (SIHF) START NOW Breast Health Services Program. START NOW’s focus is to increase awareness of the life-saving benefits of early breast cancer detection and increase breast health services to uninsured and underserved women in St. Clair, Madison and Clinton Counties.
This is the seventh year that START NOW has received funding from the Avon Breast Cancer Crusade in recognition of its excellence in increasing breast health importance, targeting and reaching the more at-risk population, and reducing the timeline of services. Since January 2009, START NOW has reached more than 7,510 women with information about the importance of early breast cancer detection and has referred almost 3,600 women for mammograms and clinical breast exams.
START NOW is a community-based breast health navigation program, culturally designed to adapt to the social determinant of health as well as the health disparity of the women it serves. START NOW educates women at both SIHF’s health centers and its affiliate hospital, Touchette Regional Hospital, and refers them to low-cost or free mammograms and clinical breast exams in their own communities. The dedicated START NOW team provides a complete continuum of care with education, support and navigation of treatment, beginning with outreach through five years of survivorship.
Breast cancer is the most common form of cancer in women in the United States. According to the American Cancer Society, 9,570 new cases of breast cancer will be detected in Illinois this year, and 1,650 lives will be lost. While advances have been made in prevention, diagnosis, treatment, and cure, early detection still affords the best opportunity for successful treatment. Programs such as START NOW help ensure that all women, including the poor and medically underserved, have access to early detection information and options.
“We are proud that the Avon Breast Cancer Crusade shares our mission and has chosen to support our program,” said Debra Custer, Program Manager with START NOW. “With these funds we will be able to continue to provide breast health services to women we serve, with the goal in mind to increase awareness and reduce identifying late staged breast cancers.”
Since 1993, the Avon Breast Cancer Crusade has awarded more than 1,800 grants to community-based breast health programs across the United States, including START NOW. The Avon Breast Cancer Crusade awards funding to beneficiaries ranging from leading cancer centers to community-based grassroots breast health programs to support breast cancer research and access to care. Many programs are dedicated to educating underserved women about breast cancer and linking them to early detection screening services. Visit www.avonbhop.org for more information.
The Avon Breast Health Outreach Program is administered by Cicatelli Associates Inc. to support community-based, non-profit breast health programs across the country. The Fund's National Advisory Board selected START NOW as one of 56 new grant recipients nationwide in the 2016 cycle of Avon Breast Health Outreach Program grants. These organizations were chosen based on their ability to effectively reach women, particularly minority, low-income, and older women, who are often medically underserved.