Never Smoked. Lived Right. Died of Lung Cancer.

By Rich Barlow

Avrum Spira’s aunt died of lung cancer almost 20 years ago. She was a nonsmoking exercise buff in her 40s who hadn’t been exposed to any known toxins; she worked in a government office, not a coal mine. “One of the healthiest people you could imagine, did everything right,” says Spira (ENG’02), who at the time was an internal medicine resident at the University of Toronto.

The one thing she didn’t do right wasn’t her fault: she’d been born to a nonsmoking mother who had died from the same illness. “I’m absolutely convinced she had a genetic predisposition” to lung cancer, says Spira, a School of Medicine professor and chief of computational biomedicine. That conviction set him on a quest for the genetic key to a medical mystery: why some people who have never smoked fall victim to this scourge of cigarette users.

Lung cancer kills more Americans than any other cancer, and twice as many women die from it than from breast cancer, although the latter gets greater public attention, says Spira. In 2008, the last year for which data was available, more than 208,000 Americans were diagnosed with lung cancer and almost 158,600 died from it. Spira says between 10 and 15 percent of these annual victims are nonsmokers (the percentage has been edging up slowly in recent years) with no apparent exposure to other toxins—a crucial caveat. “How do you know someone has been or has not been exposed to something in the environment?” he asks. Some potential toxins, like radon, are invisible, he notes, “so people who we’re seeing now, with higher rates of nonsmoking lung cancer—is it because they were exposed to radon 20 years ago?”

It’s true that worldwide, the rise in the incidence of lung cancer—from the eighth leading cause of death in 1990 to fifth in 2010—is mostly a function, perversely, of good news: as living standards have improved in the developing world, more people survive into adulthood, meaning a decline in childhood deaths from malnutrition and infectious diseases. That has brought an accompanying uptick in the number of people dying from diseases mostly found in wealthier countries, among them cancer. Moreover, air pollution in industrializing countries has resulted in more lung cancer in nonsmokers there, Spira says.

But in the United States, he says, doctors believe there’s a similar spurt in lung cancers in nonsmokers who’ve had no apparent contact with other toxins. The most extensive studies, incorporating detailed questionnaires and visits to peoples’ homes to see their environment, show that “there hasn’t been a clear association among nonsmokers who are getting lung cancer with exposures to other things.”

An ongoing, as-yet-unpublished study by a team that includes Spira is looking at tumor tissue and adjacent, noncancerous tissue from the lungs of 32 subjects with lung cancer: 8 smokers, 11 former smokers, and 13 who never smoked and had no apparent exposure to other toxins. The researchers ran the samples through a gene sequencer at MED, which “can give us unprecedented insight into the genomic changes leading to lung cancer” in nonsmokers, says Rebecca Kusko (MED’14), a graduate student spearheading the study in Spira’s lab.

With the sequencer, “we study the normal cells from each person as a control,” says Spira, “and then what happens in their tumor right next door, and say, what’s changed?” Preliminary results suggest that in the smokers, “a huge number of cancer pathways are activated,” as genes controlling cell growth in the tumors turned on. But those pathways weren’t necessarily activated in the nonsmokers, who showed different gene changes between their healthy lung tissue and their tumorous tissue. The researchers’ hypothesis is that the nonsmokers had a genetic predisposition, a pathway, to cancer that was activated by something in their environment.

That trigger, Spira theorizes, may be a viral infection (cervical, liver, and head and neck cancers are all caused by viruses, he says). The researchers are now sequencing the tumor tissue of the nonsmokers to try and find any viral genes. “Even if there’s one viral gene per million human genes, we might pick it up, we believe,” he says. The work will take a year or two.

Potential therapies—which are many more years away, he warns—might include screening people with the genetic predisposition and then giving those with the predisposition regular lung scans to catch cancers early. Another possibility would be drugs that could turn off uncontrolled growth in cancerous cells. (Spira got attention in 2010 for research suggesting that the natural compound myo-inositolcould turn off incipient lung cancer in smokers.)

Those who walk Commonwealth Avenue and have to dodge fumes from smokers on break may wonder about secondhand smoke. Research is mixed, but Spira, who researches the amount of smoke necessary to change gene expression and possibly lead to lung cancer, believes that it takes a big dose—perhaps exposure over months or years.

Almost half a century after the surgeon general first warned of smoking’s dangers, Spira says that even Hollywood is catching on that not all cancer victims heedlessly bring the disease on themselves. In 2011, he was a presenter at the Prism Awards, given for accurate portrayals of illness in entertainment media. He handed an award to an actress whose character on the soap opera The Bold and the Beautifulhad lung cancer.

The character was a nonsmoker.

Please click here to be directed to the article in BU Today.

Chronic obstructive pulmonary disease (COPD) is the third leading cause of death in the United States and is thought to affect almost three million people in the UK. New research published in BioMed Central’s open access journal Genome Medicine has identified genes whose activity is altered with increasing lung damage and, using a database of drug effects on gene activity (the Connectivity Map), finds that the compound Gly-His-Lys (GHK) affects the activity of these genes. When tested on human cells from lungs damaged by emphysema, GHK was able to restore normal gene activity and repair cell function.

The strongest cause of COPD is smoking, and at least 25% of smokers will develop this disease. Tobacco smoke and other irritants cause oxidative stress and chronic inflammation, which over time results in emphysema, the destruction of lung alveolar cells. Without these cells, the lungs are not able to efficiently exchange oxygen for carbon dioxide, leaving the patient continuously short of breath and with low levels of oxygen in their blood.

In a ground breaking, multi-centre, study funded by the National Institute of Health (NIH), researchers used cells taken from lungs donated by patients undergoing double lung transplant, whose own lungs were irrevocably damaged by COPD. Profiling of these samples showed that 127 genes had changes in activity that was associated with worsening disease severity within the lung. As would be expected from the nature of the disease, several genes associated with inflammation, such as the genes involved in signalling to B-cells (the immune system cells which make antibodies), showed increased activity.

In contrast genes involved in maintaining cellular structure and normal cellular function, along with the growth factors TGFβ and VEGF, were down-regulated and showed decreased activity. This included genes which control the ability of the cells to stick together (cell adhesion), produce the protein matrix which normally surrounds the cells, and which promote the normal association between lung cells and blood vessels.

Dr Avrum Spira and Dr Marc Lenburg, who co-led this study from the Boston University School of Medicine, explained, “When we searched the Connectivity Map database, which is essentially a compendium of experiments that measure the effect of therapeutic compounds on every gene in the genome, we found that how genes were affected by the compound GHK, a drug known since the 1970s, was the complete opposite of what we had seen in the cells damaged by emphysema.”

Dr Joshua Campbell explained, “What got us especially excited was that previous studies had shown that GHK could accelerate wound repair when applied to the skin. This made us think that GHK could have potential drug’s as a therapy for COPD.”

Prof James Hogg, from the University of British Columbia continued, “When we tested GHK on cells from the damaged lungs of smokers with COPD, we saw an improvement in the structure of their actin cytoskeleton and in cell adhesion, especially to collagen. GHK also restored the ability of cells to reorganise themselves to repair wounds and construct the contractile filaments essential for alveolar function.”

GHK is a natural peptide found in human plasma, but the amount present decreases with age. While more testing needs to be done on its effects in COPD, these early results are very promising. Therapeutic studies with GHK in animal models of COPD are now underway with the ultimate goal of moving this compound into clinical trials. As more gene activity signatures are discovered, this method of matching drug to disease may provide a rapid method for discovering potential uses for existing drugs and compounds.

Manuscript Reference:

A gene expression signature of emphysema-related lung destruction and its reversal by the tripeptide GHK
Joshua D Campbell, John E McDonough, Julie E Zeskind, Tillie L Hackett, Dmitri V Pechkovsky, Corry-Anke Brandsma, Masaru Suzuki, John V Gosselink, Gang Liu, Yuriy O Alekseyev, Ji Xiao, Xiaohui Zhang, Shizu Hayashi, Joel D Cooper, Wim Timens, Dirkje S Postma, Darryl A Knight, Marc E Lenburg, James C Hogg and Avrum Spira
Genome Medicine 2012, 4:67

Please click here to download manuscript editorial published in Genome Medicine entitled, “Next-generation personalized drug discovery: the tripeptide GHK hits center stage in chronic obstructive pulmonary disease”.

Researchers from Dana-Farber Cancer Institute, the Broad Institute, Boston University and colleagues have found a molecular “signature” in a common form of lymphoma that identifies patients unlikely to respond to standard chemotherapy, and who might benefit instead from treatment with certain experimental targeted drugs.

The discovery came from a massive, fine-grained analysis of DNA structure and gene expression in tumors from patients with diffuse large B cell lymphoma (DLBCL), a cancer of white blood cells. It is the most common form of non-Hodgkin lymphoma. The findings are published in the Sept. 11 issue of Cancer Cell.

“We think that capturing this signature will identify a group of patients whose tumors have a genetic basis for deregulated cell growth,” said Margaret Shipp, MD, chief of the Division of Hematologic Neoplasia at Dana-Farber and senior author of the study. “These tumors are less likely to respond completely to standard chemotherapy. Because we now know the basis of this deregulated cell growth, these results suggests ways to target it.”

About 60 percent of patients with DLBCL can be cured with current therapy — a combination of a monoclonal antibody and four drugs – while the remaining 40 percent are not, and have an unfavorable prognosis. This study defines genetic and biological mechanisms that underlie the differing responses, said Shipp.

In many cancers, scientists have discovered major mutations that drive tumor growth and whose presence or absence can predict treatment outcome, as well as providing targets for selective drugs. Such dominant mutations are less common in DLCBL, which is “much more genetically complicated,” said Shipp, who is also the director of the Lymphoma Program at Dana-Farber. Until recently, oncologists assessed outcomes using a set of clinical features such as age, tumor size and pattern, and some easily measured parameters in blood tests. “But these don’t tell you about the basic biology of the disease or how you might treat it more effectively.”

Poorer response to chemotherapy has been linked to DLBCL tumors whose cells are proliferating rapidly, Shipp noted, though the reason wasn’t known.

In the new study, researchers used a new genomic platform, called high-density SNP arrays, to search for subtle changes on chromosomes known as copy number alterations (CNA). Unlike mutations that disable a gene or cause it to go into overdrive, CNAs change gene dosage by increasing or decreasing gene copy numbers. Advanced genomic methods are needed to detect these alterations.

The analysis provided “much higher resolution and a much more fine-grained map of the alterations” han previous studies,” said Shipp. In addition, the researchers measured variations in gene expression across the DLBCL genomes, and combined those results with the CNA map.

Together, these experiments revealed a complex pattern of CNAs and associated gene expression changes in DNA samples from patients who were poor responders to chemotherapy. By contrast, the analysis found “clean” genomes, with few CNAs or gene activity abnormalities, in samples from successfully treated patients.

Together, this pattern of structural alterations and changes in gene expression formed a molecular signature predicting an unfavorable outcome with chemotherapy for DLCBL, the researchers reported. Such a test could be combined with clinical factors to improve prognostic testing, Shipp said. In addition, scientists found that the CNAs in the DNA of poor responders caused disruption of two important molecular pathways often involved in cancer.

First, the CNAs reduced activity of the p53 gene, which protects cells against genetic instability that can ead to cancer. Second, the copy number alterations stimulated genes that control cell division, causing he increased proliferation of cells previously observed in poor-prognosis DLBCL.

For bad-prognosis patients, Shipp added, the good news is that experimental drugs exist that target protein kinases that regulate cell division, and might be successful in blocking excessive cell proliferation. She said one such drug, a “pan-cyclin kinase (CDK) inhibitor” called flavopiridol, showed “nice effectiveness” against lymphoma tumors grafted onto mice. Clinical trials of panCDK inhibitors in patients are being planned, she said.

The research was funded in part by a National Institutes of Public Health grant (PO1CA092625).

The paper’s joint first authors are Stefano Monti, PhD, formerly of the Broad Institute and now at Boston University of Medicine, and Bjoern Chapuy, MD, PhD, of Dana-Farber. The paper’s other authors, in addition to Shipp, are from Dana-Farber, the Broad Institute, Brigham and Women’s Hospital, and Dana- Farber/Children’s Hospital Cancer.

Watch the video of Dr. Spira describing this project.

For the journal article please click here.

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