{"id":1049,"date":"2009-02-03T07:14:43","date_gmt":"2009-02-03T15:14:43","guid":{"rendered":"http:\/\/www.ibiblio.org\/carrborocitizen\/mill\/?p=1049"},"modified":"2009-02-03T07:14:43","modified_gmt":"2009-02-03T15:14:43","slug":"circadian-clock-and-cancer-progression-linked","status":"publish","type":"post","link":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/2009\/02\/circadian-clock-and-cancer-progression-linked\/","title":{"rendered":"Circadian clock and cancer progression linked"},"content":{"rendered":"<p>This from UNC:<\/p>\n<blockquote><p>\n<strong>UNC study: Tinkering with the circadian clock can suppress cancer growth<\/strong><\/p>\n<p>CHAPEL HILL &#8211; Researchers at the University of North Carolina at Chapel<br \/>\nHill have shown that disruption of the circadian clock &#8211; the internal<br \/>\ntime-keeping mechanism that keeps the body running on a 24-hour cycle &#8211;<br \/>\ncan slow the progression of cancer. <\/p>\n<p>The study disputes some of the most recent research in the field<br \/>\nindicating that alteration of this daily cycle predisposes humans and<br \/>\nmice to cancer. The UNC researchers found that genetically altering one<br \/>\nof four essential &#8220;clock&#8221; genes actually suppressed cancer growth in a<br \/>\nmouse model commonly used to investigate cancer. The findings could<br \/>\nenable clinicians to reset the internal clock of each cancer cell to<br \/>\nrender it more vulnerable to attack with chemotherapeutic drugs.  <!--more--><\/p>\n<p>&#8220;Adjusting the clock in this way could certainly be a new target for<br \/>\ncancer treatment,&#8221; said senior study author Aziz Sancar, M.D., Ph.D., a<br \/>\nmember of the UNC Lineberger Comprehensive Cancer Center and Sarah<br \/>\nGraham Kenan Professor of Biochemistry and Biophysics in the UNC School<br \/>\nof Medicine. Sancar is also a member of the National Academy of<br \/>\nSciences, the Turkish Academy of Sciences and the American Academy of<br \/>\nArts and Sciences.<\/p>\n<p>&#8220;Our study indicates that interfering with the function of these clock<br \/>\ngenes in cancer tissue may be an effective way to kill cancer cells and<br \/>\ncould be a way to improve upon traditional chemotherapy,&#8221; Sancar said.<br \/>\nHis findings appear in the Feb. 2, 2009 online early edition of the<br \/>\nProceedings of the National Academy of Sciences.<\/p>\n<p>Previous research has shown that the disruption of the body&#8217;s natural<br \/>\ncircadian rhythms affects people&#8217;s health. One of the largest<br \/>\nepidemiological studies ever performed, the Nurses&#8217; Health Study, found<br \/>\nthat nurses who worked the night shift had a higher incidence of breast<br \/>\ncancer than those who worked days. Another study of flight attendants<br \/>\nwhose internal biological clocks had been wrecked by travel on<br \/>\ntransatlantic flights produced similar findings.<br \/>\nYet when scientists, including Sancar, began to tinker with the<br \/>\nmolecular mechanisms within the internal clocks of animal models, they<br \/>\ndid not always see such an effect. Circadian rhythms in humans and in<br \/>\nmice are controlled by &#8220;clock genes,&#8221; four of which are absolutely<br \/>\nessential. In a study four years ago, Sancar found that deleting the<br \/>\nclock gene cryptochrome in mice did not increase the incidence of cancer<br \/>\nas had previously been expected.<br \/>\nWhile altering the clock gene did not cause cancer in otherwise normal<br \/>\nmice, Sancar and his colleagues wanted to see if it would accelerate the<br \/>\ndevelopment of tumors in a mouse model that is already predisposed to<br \/>\ncancer. Therefore, in this study they modified the cryptochrome gene in<br \/>\nmice that also had defects in a gene called P53, which is mutated in<br \/>\nnearly half of human cancers. The researchers found that disturbing the<br \/>\ninternal clock in these mice did not speed up the onset of cancer, but<br \/>\ninstead had the opposite effect &#8211; it extended their lives by 50 percent.<\/p>\n<p>The researchers then wanted to know how interfering with the<br \/>\ncryptochrome gene had reduced the incidence of cancer. By closely<br \/>\nexamining the series of biological events in the disease&#8217;s development,<br \/>\nthey determined that the mutation of this clock gene reactivates the<br \/>\nintracellular signals that can eliminate cancerous cells. Sancar said<br \/>\nthis tactic essentially makes cancer cells more likely to commit cell<br \/>\nsuicide &#8211; through a process known as apoptosis &#8211; in response to the<br \/>\nstresses of UV radiation or chemotherapy.<br \/>\n&#8220;These results suggest that altering the function of this clock gene, at<br \/>\nleast in the 50 percent of human cancers associated with p53 mutations,<br \/>\nmay slow the progression of cancer,&#8221; Sancar said. &#8220;In combination with<br \/>\nother approaches to cancer treatment, this method may one day be used to<br \/>\nincrease the success rate of remission.&#8221;<br \/>\nThe research was supported by the National Institutes of Health. Study<br \/>\nco-authors from Sancar&#8217;s UNC laboratory include the lead author and<br \/>\npostdoctoral fellow Nuri Ozturk, Ph.D.; Jin Hyup Lee, a graduate<br \/>\nstudent; and postdoctoral fellow Shobhan Gaddemeedhi, Ph.D.<\/p>\n<p>The study follows the recent publication earlier this month of another<br \/>\npaper from Sancar&#8217;s laboratory in the Proceedings of the National<br \/>\nAcademy of Sciences. It suggested that chemotherapy treatment for cancer<br \/>\nis most effective at certain times of day because that is when a<br \/>\nparticular enzyme system &#8211; one that can reverse the actions of<br \/>\nchemotherapeutic drugs &#8211; is at its lowest levels in the body.<\/p>\n<p>To read the news release about the previous study, go to:<br \/>\nhttp:\/\/uncnews.unc.edu\/news\/health-and-medicine\/unc-study-supports-role-<br \/>\nof-circadian-clock-in-response-to-chemotherapy.html\n<\/p><\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>This from UNC: UNC study: Tinkering with the circadian clock can suppress cancer growth CHAPEL HILL &#8211; Researchers at the University of North Carolina at Chapel Hill have shown that disruption of the circadian clock &#8211; the internal time-keeping mechanism that keeps the body running on a 24-hour cycle &#8211; can slow the progression of [&hellip;]<\/p>\n","protected":false},"author":16,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[111,112],"class_list":["post-1049","post","type-post","status-publish","format-standard","hentry","category-miscellany","tag-health","tag-unc"],"_links":{"self":[{"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/posts\/1049","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/users\/16"}],"replies":[{"embeddable":true,"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/comments?post=1049"}],"version-history":[{"count":1,"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/posts\/1049\/revisions"}],"predecessor-version":[{"id":1050,"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/posts\/1049\/revisions\/1050"}],"wp:attachment":[{"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/media?parent=1049"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/categories?post=1049"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.ibiblio.org\/carrborocitizen\/mill\/wp-json\/wp\/v2\/tags?post=1049"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}