How We're Screwing Ourselves Out of New Cancer Drugs and Zika Meds .
By Maggie Puniewska // April 22, 2016 .
Photo by David Doubilet via Getty .
With an estimated 1.7 million new cancer diagnoses every year in the US, and outbreaks of malaria, Ebola and Zika rocking populations around the world, scientists are on a constant search for new compounds that might kill the cancer cells and microbes that threaten human life. Over the past two decades, they've turned increasingly to one important place: coral reefs.
Organisms that live in and around reefs play an integral, often understated, role in drug development. Though reefs cover less than one percent of the earth's surface, they are home to 25 percent of all ocean species, many of which have helped scientists crack some of the toughest medical puzzles: sea sponges were used to develop thebreakthrough HIV drug AZT; mollusks called sea hares in the Indian Ocean have lent their compounds to treatments for breast and prostate cancers; toxins from cone snails have become prototypes for painkillers. Scientists in Sydney are doing promising researchon coral algae to treat malaria. Last December, the FDA approved Yondelis, a cancer-fighting drug made from a compound originally isolated from a sea squirt, a small tubular marine animal that is part of the reef community. And while coral's disease-fighting resume is a bit shorter than the organisms that call it home, its role in medicine is not negligible. Made of calcium carbonate and porous in nature, it has an unusual similarity to the human skeleton and has served as a blueprint for bone graft implants.
...
Hyperthermia adds to trabectedin effectiveness and thermal enhancement is associated with BRCA2 degradation and impairment of DNA homologous recombination repair.
Oncologos Alemanes consiguen demostrar una Mejora de Calado en el Tratamiento.
Enlace :
International Journal of Cancer. 2016 Mar .
Harnicek D1, Kampmann E2, Lauber K3, Hennel R3, Cardoso Martins AS2, Guo Y4, Belka C3, Mörtl S5, Gallmeier E6, Kanaar R7, Mansmann U8, Hucl T9, Lindner LH2, Hiddemann W2, Issels RD2.
Abstract
The tetrahydroisoquinoline trabectedin is a marine compound with approved activity against human soft-tissue sarcoma. It exerts anti-proliferative activity mainly by specific binding to the DNA and inducing DNA double-strand breaks (DSB).
Since homologous recombination repair (HRR) deficient tumors are more susceptible to trabectedin, hyperthermia mediated on-demand induction of HRR deficiency represents a novel and promising strategy to boost trabectedin treatment.
For the first time, we demonstrate enhancement of trabectedin effectiveness in human sarcoma cell lines by heat and characterize cellular events and molecular mechanisms related to heat-induced effects. Hyperthermic temperatures (41.8°C or 43°C) enhanced significantly trabectedin-related clonogenic cell death and G2/M cell cycle arrest followed by cell type dependent induction of apoptosis or senescence. Heat combination increased accumulation of γH2AX foci as key marker of DSBs.
Expression of BRCA2 protein, an integral protein of the HRR machinery, was significantly decreased by heat. Consequently, recruitment of downstream RAD51 to γH2AX positive repair foci was almost abolished indicating relevant impairment of HRR by heat.
Accordingly, enhancement of trabectedin effectiveness was significantly augmented in BRCA2-proficient cells by hyperthermia and alleviated in BRCA2 knockout or siRNA transfected BRCA2 knockdown cells. In peripheral blood mononuclear cells isolated from sarcoma patients, increased numbers of nuclear γH2AX foci were detected after systemic treatment with trabectedin and hyperthermia of the tumor region.
The findings establish BRCA2 degradation by heat as a key factor for a novel treatment strategy that allows targeted chemosensitization to trabectedin and other DNA damaging antitumor drugs by on-demand induction of HRR deficiency. This article is protected by copyright. All rights reserved.
© 2016 UICC.
