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Category: Cancer (page 1 of 5)

08.30.2018

the problem with cancer cells

HeLa cells cancer research

HeLa cells, cancer cells originally isolated from Henerietta Lacks, are among the most widely used cell lines for scientific research

Cell lines are frequently used in cancer research studies. They are pretty easy to maintain and they grow fast. The cell lines give us insight into some of the cellular pathways involved in tumor biology. They are often used as early-stage screens for potential cancer therapeutics, even though scientists know that they do not exactly share the same biology as an actual tumor. Cancer cells grow rapidly and they generate many mutations in the process. In a few cycles, the cells that you have in culture are different genomically than the cells that you started with. But still, having some information on what cells maybe doing in a tumor is better than no information at all.

Now Derek Lowe calls attention to a new study in Nature, which points out a potential problem with these cell lines in culture. In this new paper, the researchers found that not only are cancer cells different from the tumor that they started from, but there can be many differences within a strains of any given cell line.  When they observed 27 strains of the MCF7 breast cancer line, the discovered rapid genetic diversification. They then looked at 13 additional cell lines and saw similar results. The genetic differences changed activation of gene expression, cell morphology and cell proliferation.

Derek Lowe sums up what this means for compound screening in cancer cell lines:

At least 75% of the compounds that showed strong inhibition of one MCF7 line were totally inactive against others. That’s going to confound experiments big-time, and this paper is a loud warning for people to be aware of this problem and to do something about it.

08.07.2014

carbs fuel colon cancer in mice

Carbohydrate rich diets, especially refined carbohydrates, have been linked to higher rates of colon cancer in the developed world, when compared to developing nations. A new report in the journal Cell,  provides insight into how this might come to be. Science News explains:

To probe the link between colon tumors and gut microbes, the researchers treated mice engineered to be prone to colon cancer with antibiotics. By eradicating intestinal bacteria, the drugs hindered malignant lumps of cells called polyps from growing in the lining of the colon and small intestines. The team then noticed that feeding the rodents a diet low in sugar and starch also reduced the growth of polyps.

The mice had two gene mutations often linked to colon cancer in people,one of which derails a cell’s ability to fix errors that arise during DNA replication, known as the mismatch DNA repair system.

A mismatch repair deficiency causes cells in the lining of the colon to divide quickly, explains study leader Alberto Martin, an immunologist at the University of Toronto. Bacteria and carbs speed the process, he says, damaging the genome and leading to tumor growth.

The researchers surmised that when microbes feast on carbohydrates, the germs must produce a chemical that pushes colon cells lacking the ability to repair DNA mismatches toward uncontrollably multiplying into tumors.

The researchers discovered that gut bacteria process carbohydrates into butyrate, which can induce cancer in  APCMin/+MSH2−/− mice by allowing cancerous  MSH2−/−cells to proliferate uncontrollably in the colon.

02.13.2014

are mammograms worth it?

A new study published in the British Medical Journal suggests perhaps they are not. From the New York Times:

[The study] found that the death rates from breast cancer and from all causes were the same in women who got mammograms and those who did not. And the screening had harms: One in five cancers found with mammography and treated was not a threat to the woman’s health and did not need treatment such as chemotherapy, surgery or radiation.

…

Researchers sought to determine whether there was any advantage to finding breast cancers when they were too small to feel. The answer is no, the researchers report.

Many of the cancers found by mammography posed no threat to women’s health and led to costly interventions that may not have been necessary. The study is not expected to change mammography guidelines though.

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