Antioxidants and nutrition support

The resveratrol analogue 4,4'-dihydroxy-trans-stilbene inhibits cell proliferation with higher efficiency but different mechanism from resveratrol

Resveratrol (3,4',5-trihydroxy-trans-stilbene) is a natural phytoalexin found in grapes and wine, which shows antiproliferative activity. We previously found that 4-hydroxy group in the trans conformation was absolutely required for the inhibition of cell proliferation. In the present work we have synthesized the resveratrol analogue 4,4'-dihydroxy-trans-stilbene, which contains two OH in 4' and 4 positions, with the aim of developing a compound with an antiproliferative potential higher than that of resveratrol, on the basis of the correlation between structure and activity previously observed. In comparison with resveratrol, 4,4'-dihydroxy-trans-stilbene inhibited cell clonogenic efficiency of fibroblasts nine times more although with a different mechanism. First, 4,4'-dihydroxy-trans-stilbene induced predominantly an accumulation of cells in G1 phase, whereas resveratrol perturbed the G1/S phase transition. Second, although both compounds were able to inhibit DNA polymerase (pol) delta in an in vitro assay, 4, 4'-dihydroxy-trans-stilbene did not affect pol alpha activity. Finally, 4,4'-dihydroxy-trans-stilbene increased p21(CDKN1A) and p53 protein levels, whereas resveratrol led to phosphorylation of the S-phase checkpoint protein Chk1. Taken together, our results demonstrated for the first time that the two hydroxyl groups on 4- and 4'- positions of the stilbenic backbone enhance the antiproliferative effect and introduce additional targets in the mechanism of action of resveratrol. In conclusion, 4,4'-dihydroxy-trans-stilbene has potent antiproliferative activities that differ from the effect of resveratrol shown in this system, suggesting that it warrants further development as a potential chemopreventive or therapeutic agent.

Multiple molecular targets of resveratrol: Anti-carcinogenic mechanisms

Plant-derived polyphenolic compounds, such as the stilbene resveratrol (trans-3,4',5-trihydroxystilbene), have been identified as potent anti-cancer agents. Extensive in vitro studies revealed multiple intracellular targets of resveratrol, which affect cell growth, inflammation, apoptosis, angiogenesis, and invasion and metastasis. These include tumor suppressors p53 and Rb; cell cycle regulators, cyclins, CDKs, p21WAF1, p27KIP and INK and the checkpoint kinases ATM/ATR; transcription factors NF-kappaB, AP-1, c-Jun, and c-Fos; angiogenic and metastatic factors, VEGF and matrix metalloprotease 2/9; cyclooxygenases for inflammation; and apoptotic and survival regulators, Bax, Bak, PUMA, Noxa, TRAIL, APAF, survivin, Akt, Bcl2 and Bcl-X(L). In addition to its well-documented anti-oxidant properties, there is increasing evidence that resveratrol exhibits pro-oxidant activity under certain experimental conditions, causing oxidative DNA damage that may lead to cell cycle arrest or apoptosis. This review summarizes in vitro mechanistic data available for resveratrol and discusses new potential anti-cancer targets and the antiproliferative mechanisms of resveratrol.

Discrepant views of oncologists and cancer patients on complementary/alternative medicine

GOALS

Complementary/ alternative medicine (CAM) is widely used by patients but rarely discussed with oncologists. To understand reasons for the communication gap, this study compares physicians and patients on perceived reasons for CAM use and nondisclosure of use, reactions of physicians to disclosure, and expectations for CAM.

PATIENTS AND METHODS

Cross-sectional studies assessed 82 physicians (response 68.3%) and 244 of 374 outpatients (response 65.2%) identified as CAM users at the MD Anderson Cancer Center. Data were summarized by frequency and compared using chi-square tests.

MAIN RESULTS

Physicians were more likely (p<0.001) than patients to attribute CAM use to hope (chi2=17.7), control (chi2=17.5), incurable disease (chi2=42.8), or a nontoxic approach (chi2=50.9). Both physicians and patients agreed CAM could relieve symptoms/side effects, but physicians were less likely (p<0.001) than patients to expect that CAM improved immunity (chi2=72.2) or quality of life (chi2=17.1), cured disease (chi2=42.5), or prolonged life (chi2=58.4). Physicians and patients responded differently (p<0.005) on reasons for nondisclosure. Physicians believed patients felt CAM discussions were unimportant (chi2=7.9) and physicians would not understand (chi2 =48.1), discontinue treatment (chi2=26.4), discourage or disapprove of the use (chi2=131.7); patients attributed nondisclosure to their uncertainty of its benefit (chi2=10.4) and never being asked about CAM (chi2=9.9) by physicians. Physicians were more likely (chi2=9.5, p<0.002) to warn of risks and less likely (chi2=23.5, p<0.001) to encourage use than patients perceived.

CONCLUSION

Oncologists and cancer patients hold discrepant views on CAM that may contribute to a communication gap. Nevertheless, physicians should ask patients about CAM use, discuss possible benefits, and advise of potential risks.

Complementary and alternative medicine: opportunities and challenges for cancer management and research

Given the widespread use of diverse complementary and alternative medicine (CAM) approaches by cancer patients, research to establish their safety and efficacy is critical as is improved patient-physician communication about their possible risks and benefits. The mission of the National Center for Complementary and Alternative Medicine (NCCAM) is to support exacting research and disseminate clear and compelling information on CAM. Although many of the challenges facing such research are not unique to CAM, these approaches do present unique challenges, but the opportunities are many for prevention, palliation, and even treatment. Using the current research portfolio of NCCAM to illustrate how the field may mature, this report summarizes the challenges facing CAM investigators, the most fruitful areas for exploration, and existing information resources.

Nutrient support in hematopoietic cell transplantation

High-dose cytoreduction and hematopoietic stem cell infusion form the basis for treatment of hematologic cancers, defects or failure of hematopoiesis, and some solid tumors. As an antitumor therapy, allogeneic hematopoietic cell transplantation (HCT) is superior to autologous HCT by induction of a graft-vs-tumor effect. However, recipients of allografts suffer higher transplant-related mortality owing to graft-vs-host disease (GVHD). Nutrition support research must recognize that HCT is a heterogeneous modality whose short and long-term outcomes are affected by transplant type, preparative regimens, diagnosis, disease stage, age, and nutritional status. The field of HCT will diversify further as lower dose cytoreduction and mixed chimerism grafts allow expansion of the technique to older patients and to other diseases.

Complementary/alternative medicine use in a comprehensive cancer center and the implications for oncology

PURPOSE

Oncologists are aware that their patients use complementary/alternative medicine (CAM). As cancer incidence rates and survival time increase, use of CAM will likely increase. This study assessed the prevalence and predictors of CAM use in a comprehensive cancer center.

SUBJECTS AND METHODS

Subjects were English-speaking cancer patients at least 18 years of age, attending one of eight outpatient clinics at The University of Texas M.D. Anderson Cancer Center, Houston, TX, between December 1997 and June 1998. After giving written informed consent, participants completed a self-administered questionnaire. Differences between CAM users and nonusers were assessed by chi(2) and univariate logistic regression analysis. A multivariate logistic regression model identified the simultaneous impact of demographic, clinical, and treatment variables on CAM use; P values were two-sided.

RESULTS

Of the 453 participants (response rate, 51.4%), 99.3% had heard of CAM. Of those, 83.3% had used at least one CAM approach. Use was greatest for spiritual practices (80.5%), vitamins and herbs (62.6%), and movement and physical therapies (59.2%) and predicted (P <.001) by sex (female), younger age, indigent pay status, and surgery. After excluding spiritual practices and psychotherapy, 95.8% of participants were aware of CAM and 68.7% of those had used CAM. Use was predicted (P <.0001) by sex (female), education, and chemotherapy.

CONCLUSION

In most categories, CAM use was common among outpatients. Given the number of patients combining vitamins and herbs with conventional treatments, the oncology community must improve patient-provider communication, offer reliable information to patients, and initiate research to determine possible drug-herb-vitamin interactions.