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What if we didn't try to cure cancer, but simply kept tumors from growing too big? That's what radiologist Robert Gatenby of the Moffitt Cancer Center proposes this week in the journal Nature. Gatenby argues that high doses of powerful chemotherapies wreak havoc on a patient's immune system and foster the rapid regrowth of chemoresistant cancers that doctors have no hope of fighting.  So instead of curing cancer, he suggests doctors aim to stabilize the tumor at a tolerable size. In practice, this would mean that doctors identify a target size for an individual tumor that gives the patient the best quality of life.  Then, they will regularly monitor the tumor's growth with medical imaging equipment like a PET/CT scanner (see photo), and regulate doses of anticancer drugs to maintain it at a precise volume.

The in vitro study, reported in the journal Carcinogenesis (Vol. 27, pp. 32-42), showed that vitamin D, in the form of the highly active 1alpha, 25-dihydroxyvitamin D3 (1,25-VD), inhibited the function of protease enzymes that are involved in tumour invasion. "We found that 1,25-VD decreased matric metalloproteinases (MMP-9) and cathepsins (CPs), while it [also] increased the activity of their counterparts, tissue inhibitors of metalloproteinase-1 (TIMP-1) and cathepsin inhibitors," wrote lead author Bo-Ying Bao from the University of Rochester and Taipei Medical University. "Mechanistic studies showed that 1,25-VD did not suppress MMP-9 expression at the transcriptional level, but reduced its mRNA stability," said Bao.

Induction of ovarian cancer cell apoptosis by 1,25-dihydroxyvitamin D3 through the down-regulation of telomerase. Jiang F, Bao J, Li P, Nicosia SV, Bai W. J Biol Chem. 2004 Dec 17;279(51):53213-21. Epub 2004 Oct 12. PMID: 15485861 doi: 10.1074/jbc.M410395200 Overall, the study suggests that the down-regulation of telomerase activity by 1,25(OH)2VD3 and the resulting cell death are important components of the response of OCa cells to 1,25(OH)2VD3-induced growth suppression. Progressive shortening of telomere associated with cell divisions limits the life span of normal cells and eventually leads to senescence. To become immortal, human cancers including OCa are invariably associated with activation of mechanism that maintains telomere length. Approximately 85-90% of cancers show reactivation of telomerase. The present study shows that telomerase in OCa cells is down-regulated by 1,25(OH)2VD3. Down-regulation of telomerase is due to decreased stability of hTERT mRNA rather than VDRE-mediated transcriptional repression through the putative VDRE present in the regulatory region of the hTERT gene. It is known that the inhibition of telomerase may lead to a phenotypic lag during which cells would continue to divide until the point at which the telomeres became critically short. This phenomenon may explain why the apoptotic induction by 1,25(OH)2VD3 needs the treatment for more than 6 days. As mentioned in the results, no detectable shortening of telomeric repeats was observed in parental OVCAR3 cells after 9 days of treatment with 1,25(OH)2VD3 (Fig. 4D). This is likely due to the fact that the short telomere (about 3 kb) in OVCAR3 cells is very close to the minimal length required for survival and that cells with detectably shorter telomere may have been selected against apoptosis. It has been shown that transformed human cells enter crisis once the terminal restriction fragment of the telomere reaches a length of about 4 kb. This is insufficient to protect chro

In part I of antobody engineering, IgG construction has introduced, apart from which there are another two that antibody engineers focused much of their efforts on, antibody stability improvement and scFv/Fab construction.