Tag Archives: cancer

Dogs inhale new immunotherapy to fight lung cancer

Posted on June 12, 2022 | Leave a comment

A protein that the body naturally produces could become an important new immunotherapy drug in the cache of cancer-fighting tools available to oncologists. UC Davis cancer researchers for both companion dogs and humans joined scientists from other institutions to study a new approach that triggers the body’s defense mechanisms, its T-cells and natural killer (NK) cells, to respond and destroy cancer. 

Oncologist Robert Canter said an inhaled immunotherapy for dogs with cancer shows promise for human cancer patients.

Surgical oncologist Robert J. Canter with UC Davis Comprehensive Cancer Center and canine oncologist Robert B. Rebhun with the UC Davis School of Veterinary Medicine are corresponding authors for a study just published in the Journal for ImmunoTherapy of Cancer.

In the first-of-its-kind Phase 1 clinical trial, 21 pet dogs of various breeds that had metastatic lung disease resulting from osteosarcoma or melanoma were treated with protein interleukin-15 (IL-15). Although previously recognized for immunotherapy properties, IL-15 has undergone few human clinical trials because of toxicity risks associated with concentrated doses. 

“No one previously had administered IL-15 as an inhaled treatment in dogs to deliver it directly to the site of the cancer. We came up with that idea as a means of reducing exposure to the rest of the body, in order to improve the benefit-risk ratio, to improve the immune stimulating effects, and to reduce toxicity,” Canter explained. “In this study, we used interleukin-15 to reinvigorate the immune system to make it recognize the cancer cells that had evaded the immune system and eliminate them.” 

The research shows that amplified concentrations of IL-15 can stimulate immune system defenses against some types of cancers in dogs. IL-15 is one of several types of cytokines—substances that have signaling and regulating functions in immune system activity.

“As part of our comparative oncology research, we are strong advocates of clinical trials in companion dogs, especially for immunotherapy, as a way to speed bench-to-bedside translation,” said Canter, who is chief of the UC Davis Division of Surgical Oncology and co-director of the comparative oncology training program at UC Davis. “The cancers that afflict dogs, including sarcomas, brain tumors, lymphoma and melanoma, are incredibly similar to cancers that humans develop.” 

UC Davis received a $2 million National Cancer Institute grant to fund the comparative oncology training program to support the next generation of oncology researchers collaborating on curing cancer in both humans and dogs. For instance, osteosarcoma and melanoma that develop elsewhere in the body commonly spread to the lung, in dogs as well as humans. 

Methodology

In the study, conducted between October 2018 and December 2020, the dogs inhaled a mist containing IL-15 twice daily. Doses were increased over time, to help determine not only effectiveness, but also tolerable levels and the ceilings above which toxicity would result. Dogs exhibited significant responses within 14 days after they began inhaling the IL-15 mist. 

Tumors shrank dramatically in two dogs in the study, including one that went into complete remission for more than a year. Cancer that had been growing rapidly in five other dogs stabilized for several months. “Our overall response rate, the clinical benefit rate, was close to 40%,” Canter said. 

For that and other reasons, additional studies are needed, noted Rebhun, a professor in the UC Davis School of Veterinary Medicine’s Department of Surgical and Radiological Sciences. 

“The inhaled IL-15 responses that we’ve seen in dogs are better than prior human studies, but clinical benefit is seen in less than half of the dogs. Using IL-15 in people has led to potentially favorable immune responses but has not yielded good tumor responses. This indicates that combining IL-15 with other immunotherapies may result in additive or synergistic responses,” said Rebhun, who holds the Maxine Adler Endowed Chair in Oncology and is the associate director of the cancer program in the Center for Companion Animal Health. 

Key findings

In his view, the study yielded two significant findings: the therapy was well tolerated, and even a short two-week course of inhaled IL-15 could lead to sustained suppression of advanced and diffuse metastatic cancer. Both he and Canter noted that in eventual clinical application, IL-15 likely would be used not as a standalone therapy, but as a reinforcement in combination with other treatments. 

“All of the canine patients in this study had advanced metastatic cancer, and the majority already had received prior chemotherapy, radiation therapy and, in some cases, immunotherapy. Studies are ongoing now to see whether we can predict which patients might respond to this therapy based on properties of the tumor or the patient’s immune status,” Rebhun said. 

“This may help us identify patients that might respond to this therapy, as well as help us understand how to potentially combine other immunotherapies to improve response rates. We are grateful to the extremely dedicated clients who sought any and all possible care for their pets, elected to enroll them in this study, and even delivered the inhaled IL-15 to their dogs at home—in hopes that it could benefit their dog, other dogs, or possibly even people with advanced metastatic cancer,” Rebhun said. 

Other authors of the study included UC Davis researchers Daniel York, Sylvia M. Cruz and Sean J. Judge, along with Colorado State University scientists Rachel V. Brady and Jenna H. Burton, and Louisiana State University researcher Sita S. Withers. 

As part of the grant for the study, the National Institutes of Health supplied the recombinant IL-15, which it expressed from source materials. The study was supported in part by National Institutes of Health and the National Cancer Institute.

Source: UC Davis

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Eddie

Posted on November 9, 2020 | 1 comment

I said goodbye to Eddie on Saturday. With his Mum’s permission, I am writing this post.

Eddie and I first met in June 2016 when he was the tender age of 11 weeks. He was the newest addition to a family that already included his French Bulldog sister, Jorgie – also a regular massage customer.

As he rapidly grew, he developed his rugby player neck which earned him my nickname “My Little Boofhead.” It didn’t take him long to understand that the table meant massage – leaping up to get started:

I would set up for massage downstairs and then brace myself for Eddie and Jorgie to arrive

In the intervening 4+ years, Eddie proved to be an enthusiastic Lover and not a Fighter (contrary to what so many people believe about Bull Breed dogs). Always eager to please, he learned strengthening and rehab exercises quickly.

He was also an Over-Sharer – I lovingly called him this because he would often howl in my ear for part of his massage session. I am convinced he wanted me to know everything he had been doing since I last saw him. (I just wish he had come with subtitles and a volume control).

Eddie was one of those dogs that seemed to go from crisis to crisis. He needed soft palate surgery after suffering from enlarged tonsils, he developed digestive problems that did not respond to various therapies and, after biopsy, was diagnosed with IBD. He then ingested rat poison when visiting a neighbour and had to go to the emergency vet for what was – thankfully – a quick intervention. He then ruptured one cruciate and had surgery followed by 12 weeks of rehab- only to become a statistic and rupturing the other in good measure.

And then in September, just as it looked like we had fully rehabbed him from his second cruciate surgery and he was ready to strengthen and return to normal activity, out of the blue he developed pancreatitis that wasn’t linked to a food indiscretion.

As it turned out, his ultrasound revealed that Eddie was likely suffering from stomach cancer and our focus turned to his quality of life. Eddie’s mum asked that we continue laser therapy for pain relief, knowing that laser therapy is contraindicated in cases of cancer – this was about keeping him happy and comfortable as a cure was not possible.

Eddie’s time has come. A follow-up scan has shown that his tumour has grown significantly and, tomorrow morning, he will be helped across the Rainbow Bridge.

In Eddie’s case, I see him mounting the Bridge in his custom-built stairlift (this video made him something of a Facebook star with some loyal followers on my page).

Eddie has taught me a lot about living in the moment; no matter what the health challenge of the time, he seemed to roll with it. But cancer is a wasting disease and only in the last few weeks did we notice how flat he had become – definitely not his normal self.

Goodbye, My Little Boofhead. It’s been quite a ride – one that I wish would have lasted for much longer.

Kathleen Crisley, Fear-Free certified professional and specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

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Tracking the working dogs of 9/11

Posted on September 27, 2020 | Leave a comment

When veterinarian Cynthia Otto was in Manhattan in the wake of the 9/11 attacks helping support the search and rescue dogs, she heard rumors about the possible impact on the dogs’ long-term health.

“I was at Ground Zero and I would hear people make comments like, ‘Did you hear that half of the dogs that responded to the bombing in Oklahoma City died of X, Y, or Z?’ Or they’d say dogs responding to 9/11 had died,” she recalls. “It was really disconcerting.” 

Cynthia Otto (center) cared for search-and-rescue dogs during their work at the 9/11 disaster site, later studying the impact of their service on their health. (Image: Courtesy of Cynthia Otto)

It also underscored to her the importance of collecting rigorous data on the health of dogs deployed to disaster sites. An initiative that launched in the weeks after the Sept. 11, 2001, terrorist attacks did just that, and this week, 19 years later, Otto and colleagues’ findings offer reassurance. Dogs that participated in search-and-rescue efforts following 9/11 lived a similar length of time, on average, compared to a control group of search-and-rescue dogs and outlived their breed-average life spans. There was also no discernible difference in the dogs’ cause of death.

“Honestly this was not what we expected; it’s surprising and wonderful,” says Otto, director of the School of Veterinary Medicine’s Working Dog Center, who shared the findings in the Journal of the American Veterinary Medical Association. 

While postmortem results showed that dogs that deployed after the 9/11 attacks had more particulate material in their lungs upon their death, it seems this exposure didn’t cause serious problems for the animals in life. The most common cause of death were age-related conditions, such as arthritis and cancer, similar to the control group.

During and in the immediate aftermath of the 9/11 response, Otto and colleagues reached out to handlers to recruit search-and-rescue dogs into a longitudinal study that would track their health, longevity, and cause of death. They recruited 95 dogs that had worked at the World Trade Center, Fresh Kills Landfill, or Pentagon disaster sites. As a control group, they also included in the study 55 search-and-rescue dogs that had not deployed to 9/11.

As part of being involved, the dogs received annual medical examinations, including chest X-rays and blood work. When the dogs died, the researchers paid for the handlers to have veterinarians collect samples of various organ tissues and send them for analysis at Michigan State University. Forty-four of the 9/11 dogs and 19 of the control group dogs underwent postmortems. For most of the other dogs in the study, the research team obtained information on cause of death from medical records or the handlers themselves.

While the team had expected to see respiratory problems in the exposed dogs—conditions that have been reported by human first responders to 9/11—they did not.

“We anticipated that the dogs would be the canary in the coal mine for the human first responders since dogs age faster than humans and didn’t have any of the protective equipment during the response,” Otto says. “But we didn’t see a lot that was concerning.”

In fact, the median age at death for 9/11 dogs was about the same as the control group: 12.8 compared to 12.7 years. The most common cause of death for the dogs that deployed was degenerative causes—typically euthanasia due to severe arthritis—followed closely by cancer, though the risk of cancer was about the same as in control group dogs. 

Otto and her colleagues have ideas for why the foreign particulate matter found in some of the dog’s lungs did not translate to ill health, though they emphasize that they’re speculations, not yet based in data. 

“For the pulmonary effects, it’s somewhat easier to explain because dogs have a really good filtering system,” Otto says. “Their lungs are different—they don’t get asthma, for example—so it seems like there is something about their lungs that’s more tolerant than in humans.”

She notes that working dogs tend to be extremely physically fit compared to pet dogs, perhaps counteracting any ill effects of the deployment conditions on health. But working dog handlers and trainers can always do more to focus on fitness and conditioning, especially because doing so could slow the progression of arthritis, a disease which played a role in the death of many dogs in the study.

“We know when people stop moving, they gain weight and that puts them at a higher risk of arthritis, and arthritis makes it painful to move, so it’s a vicious cycle,” she says. “The same can be true of dogs.”

The mind-body connection may also help explain the difference between humans and dogs and the longevity of the working dogs, Otto says, as dogs don’t necessary worry and experience the same type of stress in the wake of a disaster.

“These dogs have an incredible relationship with their partners,” Otto says. “They have a purpose and a job and the mental stimulation of training. My guess is that makes a difference, too.”

Cynthia Otto is director of the Penn Vet Working Dog Center and professor of working dog sciences and sports medicine in the Department of Clinical Sciences and Advanced Medicine at the University of Pennsylvania School of Veterinary Medicine.

Source: University of Pennsylvania, Penn Today

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Scout: Super Bowl Ad Star

Posted on February 6, 2020 | Leave a comment

In the 2019 Super Bowl, Scout the Golden Retriever featured in an advertisement for WeatherTech and their PetComfort feeding system.

But this year, CEO David MacNeil  paid $6 million dollars for a 30-second ad that didn’t promote his business.  Rather, it featured Scout and the veterinary school in Wisconsin that saved his life.

In July 2019, Scout collapsed and was diagnosed with hemangiosarcoma, an aggressive cancer that formed in his heart.  Scout was treated at the University of Wisconsin in Madison and MacNeil decided to help them raise money for research by taking out the ad.

Here are both of Scout’s commercials:

 

Kathleen Crisley, Fear-Free certified professional and specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

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Estrogen’s opposing effects on mammary tumors in dogs

Posted on November 2, 2019 | Leave a comment

Dogs that are spayed at a young age have a reduced risk of developing mammary tumors, the canine equivalent of breast cancer. Early spaying reduces levels of estrogen production, leading many veterinarians and scientists to cast estrogen in a negative light when it comes to mammary cancer.

But the effects of estrogen on cancer risk in dogs aren’t straightforward, according to a new study led by researchers from Penn’s School of Veterinary Medicine. While it’s clear that spaying dogs greatly minimizes their risk of developing mammary cancer, the findings suggest that the practice may increase the risk of more aggressive cancers. And in spayed animals with mammary tumors, the team found that higher serum estrogen levels were actually protective, associated with longer times to metastasis and improved survival times.

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Veterinary oncologist Karin Sorenmo and colleagues cast new light on the complex role of estrogen in canine mammary cancer. The research emerged from Penn Vet’s Shelter Canine Mammary Tumor Program, which assists in treating and then finding homes for dogs like Brownie, pictured with former oncology intern, Kiley Daube.

“Dogs that remain intact and have their ovaries develop many more mammary tumors than dogs that were spayed, so removing that source of estrogen does have a protective effect,” says Karin U. Sorenmo, a veterinary oncologist at Penn Vet and senior author on the study, published in PLOS ONE. “Estrogen does seem to drive mammary cancer development. But what it does for progression to metastasis—that I think is more complicated.”

Sorenmo and colleagues have been studying mammary tumors in dogs as a way of improving care and treatment for pets but also to make insights into human breast cancer biology.

“Much of the research we do in veterinary medicine looks at what is done in people and then adapts it,” she says. “But dogs are such a great, comprehensive model for cancer. Yes, there are differences in biology between dogs and people, but here those differences may allow us to ask very probing questions about what estrogen is doing in both dogs with mammary cancer and women with breast cancer.”

The research used data from two prospective studies, including one involving dogs in the Penn Vet Shelter Canine Mammary Tumor Program, through which shelter dogs with mammary tumors receive treatment, are studied by researchers like Sorenmo, and then find foster or permanent homes.

The team evaluated 159 dogs with mammary cancer, 130 that were spayed as part of the study and 29 that remain intact. In addition to surgically removing the dogs’ measurable tumors, the team collected information on serum estrogen levels, tumor type, disease grade and stage, time to metastasis, and survival time.

Despite estrogen’s link with an increased risk of developing mammary tumors, the researchers found that higher serum estrogen levels also seemed to help dogs avoid some of the riskiest aspects of their disease. Unexpectedly, when dogs were spayed at the same time their tumors were removed, those with estrogen receptor-positive tumors that had higher serum estrogen took longer to develop metastatic disease and survived longer than dogs with lower estrogen levels, confirming that these tumors depended on estrogen for progression.

Sorenmo speculates that, in these cases, estrogen’s action may be nuanced. “It drives the cancer, but it also seems to control or modulate it, reining it in,” she says, because most dogs with high serum estrogen levels had lower-grade and estrogen receptor-positive tumors, rendering them susceptible to hormonal deprivation by spaying.

The protective role of estrogen was also surprisingly pronounced in dogs with estrogen-receptor negative mammary tumors. In these higher-risk cancers, high serum estrogen was associated with delayed or absent metastasis. Complementing these findings and supporting a potential broader, tumor receptor-independent anti-cancer effect driven by estrogen, dogs with low serum estrogen had a significantly increased risk for developing other non-mammary aggressive fatal tumors, such as hemangiosarcoma, during their follow-up after mammary tumor surgery.

Some of the findings contradict what has been found in women with breast cancer. For example, higher serum estrogen levels in women following breast cancer therapy have been associated with higher rates of recurrence. But Sorenmo also notes that many cases of breast cancer in women arise just after menopause, when estrogen levels tumble. So there may be a more complex role for estrogen in people’s cancer risk as well.

The work points to new possibilities for examining the role of estrogen in cancer initiation and progression. Already, Sorenmo and colleagues, including Penn Vet’s Susan Volk and Ellen Puré, are pursuing investigations of how the hormone affects the tumor microenvironment, cells that aren’t themselves cancerous but may either stem or encourage a tumor’s growth and spread.

“I think this study opens some really complicated questions,” Sorenmo says. “If we start dissecting exactly what estrogen is doing, what genes or immune cells it’s interacting with, maybe we could harness the power of estrogen to be more clever in our treatment strategies.”

Source:  Penn Today

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Muscle loss and wasting

Posted on August 6, 2018 | Leave a comment

I encounter dogs in my practice who are experiencing muscle loss and wasting fairly often.

Since owners must submit veterinary records to me for review as part of my intake process as well as update me on any subsequent vet visits, if there’s a diagnosis of chronic illness – such as kidney disease or cancer – then this muscle loss  is understandable and classified as cachexia.

In the absence of a diagnosis of disease, and working with an aging dog, then the muscle loss is classified as sarcopenia.

Muscle loss results in a change of appearance, which owners often notice first around the shoulder blades, top of the head, and around the pelvis.  Muscle wastage can be graded as noted below:

Muscle condition score

Exercise and good nutrition can be interventions with muscle loss.  Chronically ill dogs need a high quality diet that is appropriate for their disease, for example.  And aging dogs do need exercise that is targeted to their needs and abilities.

Owners should always be on the watch for signs of muscle loss – so early interventions that are medical and non-medical can be considered.

Kathleen Crisley, Fear-Free certified professional and specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

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Willa – Our Sweet Girl

Posted on September 18, 2017 | 1 comment

Willa is a special dog.

An American Pit Bull x Boxer, Willa has breast cancer which has likely spread. She’s on medication, but with time being precious, it’s important to focus on quality of life.   Willa is a popular sleepover dog at Best Friends Animal Sanctuary – every precious sleepover adds to Willa’s quality of life and enrichment.  She really enjoys getting out of kennels, getting cuddles and having a good, deep sleep.

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Willa loves rides in the car

Big smile from Willa to be in a real bed

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A special tag for a special girl

I really enjoyed staying with Willa and seeing her sweet nature in person.  Let’s hope she gets a home soon.

Kathleen Crisley, specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

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Elevated cholesterol’s link with canine osteosarcoma includes a better prognosis

Posted on August 2, 2017 | Leave a comment

Note from Doggy Mom:  I follow lots of areas of research in the canine field, but anything to do with osteosarcoma is interesting to me since greyhounds are known for suffering from this type of cancer.  Izzy is a greyhound!

Usually thought of as a health detriment, elevated cholesterol may play a role in longer survival times for dogs with a common form of bone cancer.

In addition to their veterinary significance, the findings by Oregon State University researchers advance the understanding of a type of malignant tumor, osteosarcoma, that’s often diagnosed in humans as well, typically afflicting teenagers and young adults.

Dog with cancer

A dog with osteosarcoma; Photo courtesy of Oregon State University

“This is one of the first steps into identifying cholesterol as a potential biomarker for canine osteosarcoma,” said Haley Leeper, a veterinary oncology resident at the OSU College of Veterinary Medicine. “We don’t have answers as to why high cholesterol is associated with this disease and with a better prognosis, but we’re hoping to advance these findings in future research.”

Leeper and collaborators at OSU and Iowa State University compared 64 dogs with osteosarcoma against two control groups: 30 dogs that had suffered traumatic bone fractures and 31 healthy dogs similar in age and weight to the animals with cancer.

Researchers found nearly half of the dogs with cancer – 29 of the 64 – had elevated levels of total serum cholesterol, a dramatically higher rate than occurred in either control population; just three of the 30 dogs with broken bones, and only two of the 31 healthy animals, showed high cholesterol.

Of the dogs stricken with osteosarcoma, 35 had the cancer in a leg which was subsequently amputated, followed by chemotherapy, which is the standard-of-care treatment; the dogs with elevated total cholesterol had a median survival time of 455 days, more than 200 days greater than the median survival time  for dogs with normal cholesterol.

“When people think of cholesterol they think of cheeseburgers and heart attacks,” Leeper said. “However, cholesterol is involved with many key processes and structures in the body like cell membranes, bone health and the immune system.”

Future studies that follow dogs long term and look at specific lipid content in the blood may shed light on the mechanisms behind cholesterol’s role in enhanced survival, Leeper said.

“There are a lot of things we plan on investigating,” she said. “This is exciting and fascinating, partly due to the comparative medical aspects between human research and our research.”

Source:  Oregon State University media release

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Dogs help in breast cancer research

Posted on July 16, 2017 | 1 comment

Cancer is one of the most frequent diseases not only in people, but in pets as well. Like people, dogs can also suffer from cancer of the mammary glands (mammary tumors). Dog mammary tumors are very similar to breast carcinoma in humans, and much more so than those of rats or mice, for example. For this reason, research on canine mammary tumors is important for human medicine as well. A study performed at the University of Zurich has now shown how similar mammary tumors are in both people and dogs.

Enni Markkanen, Vetsuisse-Fakultät Zürich, Untersuch Hund

Cancerous cells reprogram healthy cells

For the development of tumors and the progression of a carcinoma, not only the characteristics of the cancer cells themselves are decisive, but also the cells surrounding the tumor play a major role in this. Many tumors even have the capability to reprogram healthy cells in the tumor environment in a way that they start to support the growth of the cancerous cells. This mechanism plays an essential role in human breast carcinoma – but is it the same for dogs? The similarity of breast carcinoma in dogs and humans has been known for a long time. “But whether these tumor cells also influence the surrounding tissue in dogs the same way they do in humans was unknown until now”, explains Enni Markkanen of the Institute of Pharmacology and Toxicology of the Vetsuisse Faculty of the University of Zurich.

Archived tissues are of great value to the research

The researchers analyzed the surrounding tissue of canine mammary tumors using molecular biology and immunohistological methods. To do this, they could access the tissue archive of the Institute of Veterinary Pathology located at the Animal Hospital. “With the permission of our patient’s owners, we conduct pathological tests to better understand diseases,” says animal pathologist Alexandra Malbon. “In the process, we archive samples of various organs and tissues as these samples can be of great value to answer future research questions.”

Dogs suffering from cancer aid cancer research for humans

In the archived samples of mammary tumors from dog patients, Enni Markkanen and her team were able to prove that some cells in the vicinity of tumors behave the same way as the corresponding cells in humans: In the healthy tissue surrounding the tumor, substances are produced that promote tumor growth. “Simply speaking, the tumor enslaves its environment: It forces the surrounding cells to work for its benefit,” Markkanen adds. This mechanism works the same in both humans and dogs. For research on breast carcinoma, tumor tissue of dogs is therefore, among other reasons, much better suitable than tissue from rats or cells cultivated in the laboratory. “Importantly, however, we don’t view our dog patients as test subjects for cancer research,” Markkanen says. “But they can help us to better understand breast carcinoma in both dogs and humans and fight it more effectively.”

Source:  University of Zurich media statement

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Scientists test nanoparticle drug delivery in dogs with osteosarcoma

Posted on September 28, 2016 | Leave a comment

At the University of Illinois, an engineer teamed up with a veterinarian to test a bone cancer drug delivery system in animals bigger than the standard animal model, the mouse. They chose dogs – mammals closer in size and biology to humans – with naturally occurring bone cancers, which also are a lot like human bone tumors.

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Dogs with naturally occurring cancers are more similar in size and biology to humans than are other mammals, such as mice. Public domain photo: Wikimedia Commons

In clinical trials, the dogs tolerated the highest planned doses of cancer-drug-laden nanoparticles with no signs of toxicity. As in mice, the particles homed in on tumor sites, thanks to a coating of the drug pamidronate, which preferentially binds to degraded sites in bone. The nanoparticles also showed anti-cancer activity in mice and dogs.

The researchers report their results in the Proceedings of the National Academy of Sciences.

These findings are a proof-of-concept that nanoparticles can be used to target bone cancers in large mammals, the researchers said. The approach may one day be used to treat metastatic skeletal cancers, they said.

The dogs were companion animals with bone cancer that were submitted for the research trials by their owners, said U. of I.  Professor Dr Timothy Fan, who led the study with materials science and engineering Professor Jianjun Cheng.  All of the dogs were 40 to 60 kilograms (88 to 132 pounds) in weight, he said.

“We wanted to see if we could evaluate these drug-delivery strategies, not only in a mouse model, but also at a scale that would mimic what a person would get,” Fan said. “The amount of nanoparticle that we ended up giving to these dogs was a thousand-fold greater in quantity than what we would typically give a mouse.”

Using nanoparticles with payloads of drugs to target specific tissues in the body is nothing new, Cheng said. Countless studies test such approaches in mice, and dozens of “nanopharmaceuticals” are approved for use in humans. But the drug-development pipeline is long, and the leap from mouse models to humans is problematic, he said.

“Human bone tumors are much bigger than those of mice,” Cheng said. “Nanoparticles must penetrate more deeply into larger tumors to be effective. That is why we must find animal models that are closer in scale to those of humans.”

Mice used in cancer research have other limitations. Researchers usually inject human or other tumor cells into their bodies to mimic human cancers, Fan said. They also are bred to have compromised immune systems, to prevent them from rejecting the tumors.

“That is one of the very clear drawbacks of using a mouse model,” Fan said. “it doesn’t recapitulate the normal immune system that we deal with every day in the person or in a dog.”

There also are limitations to working with dogs, he said. Dogs diagnosed with bone cancer often arrive at the clinic at a very advanced stage of the disease, whereas in humans, bone cancer is usually detected early because people complain about the pain and have it investigated.

“On the flip side of that, I would say that if you are able to demonstrate anti-cancer activity in a dog with very advanced disease, then it would be likely that you would have equivalent or better activity in people with a less advanced stage of the disease,” Fan said.

Many more years of work remain before this or a similar drug-delivery system can be tested in humans with inoperable bone cancer, the researchers said.

Source:  Illinois News Bureau media release

Kathleen Crisley, specialist in dog massage, rehabilitation and nutrition/food therapy, The Balanced Dog, Christchurch, New Zealand

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