Postdoctoral student Parag Katira and his adviser, Roger T. Bonnecaze, department chair in the Cockrell School of Engineering and T. Brockett Hudson Professor, worked with Muhammad Zaman of Boston University to devise a 3-D cancer model that shows the softening of cells and changes in cell binding cause cancerous behavior in cells. These mechanical property changes cause cells to divide uncontrollably, making them less likely to die and resulting in malignant tumor growth. The findings present a unique physics-based perspective on understanding cancer progression and were published recently in the American Physical Society’s journal Physical Review Letters: “How Changes in Cell Mechanical Properties Induce Cancerous Behavior.

“To date, cancer research has focused on biochemical factors,” said Katira. “Instead of looking to solve numerous interdependent biochemical carcinogenic factors, we can now focus on a small number of mechanical factors. It’s a new approach.”

Cancers are caused by various genetic and carcinogenic factors, such as synthetic chemicals, radiation, the environment and physical stress. However, there is an uncanny similarity in mechanical property changes, such as degree of stiffness and ability to bind to other cells, that differentiate healthy and cancerous cells, as previously observed for several types of cancers.

Cancer cells are softer than healthy cells, and when surrounded by stiffer, healthy cells, cancerous cells stay compact and do not spread. When the number of neighboring cancerous cells increases, however, the resisting force from stiffer cells is lowered and softer cancerous cells relax and expand to cover a larger surface area. Stretching of cells increases their multiplication rate and lowers cells’ probability of death.

The team’s computational model replicates the life cycle of cells within a tissue and is used to observe how mechanical property changes affect a cell’s behavior and fate within that tissue. The team started with a completely healthy tissue where all the cells had the same stiffness and binding ability, and then softened a small cluster of cells at the center of the tissue. As long as the number of softened cells was less than a critical value, the tissue remained stable and healthy.

Past this threshold, there was an increase in the multiplication rate of softer cells compared with healthy, stiffer cells. Beyond this point, tumors grew by replacing surrounding healthy tissue and displayed clinically observed characteristics of malignant tumors. The researchers also analyzed how a cell’s ability to bind, or stick, to other cells affected metastasis, or progression. They observed that changes in the inter-cellular binding ability of softened cells controlled the rate and form of growing tumors.

The researchers believe this model identifies a common physical mechanism by which various biochemical carcinogenic or genetic factors can drive cancer progression.

NeoGenomics, Inc. is a high-complexity CLIA–certified clinical laboratory that specializes in cancer genetics diagnostic testing, the fastest growing segment of the laboratory industry. The company’s testing services include cytogenetics, fluorescence in-situ hybridization (FISH), flow cytometry, immunohistochemistry, morphology studies, anatomic pathology and molecular genetic testing. Headquartered in Fort Myers, FL, NeoGenomics has labs in Nashville, TN, Irvine, CA, Tampa, FL, and Fort Myers, FL. NeoGenomics services the needs of pathologists, oncologists, urologists and other clinicians, and hospitals throughout the United States.

“This License Agreement with NeoGenomics with their high complexity CLIA certified clinical laboratory represents a tremendous opportunity to complete the LDT development and commercialization of HDC’s cancer related products including tests for prostate cancer, pancreatic cancer, and colon cancer, as well as, the cytogenetics and flow cytometry interpretation software,” stated Stephen D. Barnhill, M.D., Chairman and Chief Executive Officer of Health Discovery Corporation. Dr. Barnhill added, “As a requirement of this Licensing Agreement, we are very excited that Dr. Maher Albitar will be the Chief Medical Officer and Director of Research and Development at NeoGenomics and will personally direct the final development and commercialization of these cancer products at NeoGenomics.”

Dr. Barnhill continued, “Under the terms of the License Agreement, NeoGenomics has agreed to use its best efforts to complete the development of these tests and have a first commercial use of products in the next 12 months, subject to extensions if required.”

The vaccine, described this week in the early edition of the journal Proceedings of the National Academy of Sciences, reveals a promising new strategy for treating cancers that share the same distinct carbohydrate signature, including ovarian and colorectal cancers.

“This vaccine elicits a very strong immune response,” said study co-senior author Geert-Jan Boons, Franklin Professor of Chemistry and a researcher in the UGA Cancer Center and its Complex Carbohydrate Research Center. “It activates all three components of the immune system to reduce tumor size by an average of 80 percent.”

When cells become cancerous, the sugars on their surface proteins undergo distinct changes that set them apart from healthy cells. For decades, scientists have tried to enable the immune system to recognize those differences to destroy cancer cells rather than normal cells. But since cancer cells originate within the body, the immune system generally doesn’t recognize them as foreign and therefore doesn’t mount an attack.

The researchers used unique mice developed by Sandra Gendler, Grohne Professor of Therapeutics for Cancer Research at the Mayo Clinic and co-senior author on the study. Like humans, the mice develop tumors that overexpress a protein known as MUC1 on the surface of their cells. The tumor-associated MUC1 protein is adorned with a distinctive, shorter set of carbohydrates that set it apart from healthy cells.

“This is the first time that a vaccine has been developed that trains the immune system to distinguish and kill cancer cells based on their different sugar structures on proteins such as MUC1,” Gendler said. “We are especially excited about the fact that MUC1 was recently recognized by the National Cancer Institute as one of the three most important tumor proteins for vaccine development.”

Gendler pointed out that MUC1 is found on more than 70 percent of all cancers that kill. Many cancers, such as breast, pancreatic, ovarian and multiple myeloma, express MUC1 with the shorter carbohydrate in more than 90 percent of cases.

She explained that when cancer occurs, the architecture of the cell changes and MUC1 is produced at high levels, promoting tumor formation. A vaccine directed against MUC1 has tremendous potential, Gendler said, as a preventative for recurrence or as a prophylactic in patients at high risk for particular cancers. A vaccine also can be used together with standard therapy such as chemotherapy in cancers that cannot be cured by surgery, such as pancreatic cancer.

Boons noted that MUC1 also is overexpressed in 90 percent of the subset of patients who are not responsive to hormonal therapy, such as Tamoxifen or aromatase inhibitors, or the drug Herceptin. These so-called “triple-negative” tumors are extremely aggressive and difficult to treat, Boons said, and a new treatment option is urgently needed.

“In the U.S. alone, there are 35,000 patients diagnosed every year whose tumors are triple-negative,” Boons said. “So we might have a therapy for a large group of patients for which there is currently no drug therapy aside from chemotherapy.”

Therapeutic vaccines received renewed attention last year when the Food and Drug Administration approved the first cancer treatment vaccine, a drug known as Provenge that is used to treat metastatic prostate cancer. Treatment with Provenge, which is manufactured in Georgia, requires clinicians to isolate immune cells from the patient and then to send the cells to a lab, where they are linked to a protein that stimulates the immune system. The cells are returned to the patient’s treating physician, who then infuses the drug over three treatments, usually two weeks apart.

Boons’ vaccine, on the other hand, is much simpler. It is fully synthetic, meaning that its components can be manufactured in a lab with assembly-line precision. The vaccine consists of three components—an immune system booster known as an adjuvant, a component that triggers the production of the immune system’s T-helper cells, and a carbohydrate-linked peptide molecule that directs the immune response to cells bearing MUC1 proteins with truncated carbohydrates.

This new technique, described today online in the American Journal of Pathology, could be the critical advance that ushers in a new era of personalized cancer medicine, and has potential application in regenerative medicine, says the study’s senior investigator, Richard Schlegel, M.D., Ph.D., chairman of the department of pathology at Georgetown Lombardi Comprehensive Cancer Center, a part of Georgetown University Medical Center.

“Because every tumor is unique, this advance will make it possible for an oncologist to find the right therapies that both kills a patient’s cancer and spares normal cells from toxicity,” he says. “We can test resistance as well as chemosensitivity to single or combination therapies directly on the cancer cell itself.”

The research team, which also includes several scientists from the National Institutes of Health, found that adding two different substances to cancer and normal cells in a laboratory pushes them to morph into stem-like cells — adult cells from which other cells are made.

The two substances are a Rho kinase (ROCK) inhibitor and fibroblast feeder cells. ROCK inhibitors help stop cell movement, but it is unclear why this agent turns on stem cell attributes, Schlegel says. His co-investigator Alison McBride, Ph.D., of the National Institute of Allergy and Infectious Diseases, had discovered that a ROCK inhibitor allowed skin cells (keratinocytes) to reproduce in the laboratory while feeder cells kept them alive.

The Georgetown researchers — 13 investigators in the departments of pathology and oncology — tried ROCK inhibitors and fibroblast feeder cells on the non-keratinocyte epithelial cells that line glands and organs to see if they had any effect. They found that both were needed to produce a dramatic effect in which the cells visibly changed their shape as they reverted to a stem-like state.

“We tried breast cells and they grew well. We tried prostate cells and their growth was fantastic, which is amazing because it is normally impossible to grow these cells in the lab,” Schlegel says. “We found the same thing with lung and colon cells that have always been difficult to grow.”

“In short, we discovered we can grow normal and tumor cells from the same patient forever, and nobody has been able to do that,” he says. “Normal cell cultures for most organ systems can’t be established in the lab, so it wasn’t possible previously to compare normal and tumor cells directly.”

The ability to immortalize cancer cells will also make biobanking both viable and relevant, Schlegel says. The researchers further discovered that the stem-like behavior in these cells is reversible. Withdrawing the ROCK inhibitor forces the cells to differentiate into the adult cells that they were initially. This “conditional immortalization” could help advance the field of regenerative medicine, Schlegel says.

However, the most immediate change in medical practice from these findings is the potential they have in “revolutionizing what pathology departments do,” Schlegel says.

“Today, pathologists don’t work with living tissue. They make a diagnosis from biopsies that are either frozen or fixed and embedded in wax,” he says. “In the future, pathologists will be able to establish live cultures of normal and cancerous cells from patients, and use this to diagnose tumors and screen treatments. That has fantastic potential.”

A researcher can use a microscope to see where and how much of the drug has been delivered because the probe emits a reddish color under special lighting or via MRI because of its optical and magnetic components.

As the drug testing continues, images can be taken over and over without any loss of optical or MRI signal. Researchers can then measure the size of the tumor and number of cancer cells that “light up” compared with the original untreated tumor.

This provides a way to determine whether the drug is doing what it is supposed to be doing in the targeted areas. The technique is much easier than the current process of removing treated cancer tumors and weighing them at regular intervals to determine the drug’s efficiency in an animal.

“Many people in my area have been studying this approach for years,” Santra said. “But we have now moved it into a live cell, not just in test tubes.”

Sudiptal Seal, the director of UCF’s NanoScience Technology Center and nanoscience scientist believes Santra’s research is significant.

“This is indeed a major breakthrough in Qdot research,” Seal said. “This new diagnostic tool will certainly impact the field of nanomedicine.”

Santra and his team used semiconductor Qdots to create the probe. Because of their small size and crystal-like structure, Qdots display unique optical and electronic properties when they get excited. These unique properties make them ideal for sustained and reliable imaging with special lights.

For this research funded by the National Science Foundation and National Institutes of Health, the UCF-led team used a superparamagnetic iron oxide nanoparticle core decorated with satellite CdS:Mn/ZnS Qdots which carried the cancer-fighting agent STAT3 inhibitor. The Qdot optical signal turned on when the probe bonded with the cancer cells.

“The potential applications for drug testing specifically for cancer research are immediate,” Santra said.

“Women die from ovarian cancer because their tumors become resistant to chemotherapy, so a drug that might be able to reduce that resistance — which may be what this combination of agents is doing — would be a boon to treatment of this difficult cancer,” says study co-author Gerardo Colon-Otero, M.D., a hematologist-oncologist who cares for ovarian cancer patients.

The finding also highlights the importance of the role of a molecule, RhoB, that the researchers say is activated by the drug duo. The study’s senior investigator, cancer biologist John Copland, Ph.D., has identified RhoB as a key modulator for drug response in other tumor types, but says its role in ovarian cancer was unknown before this study.

“Now we find that with this combination of drugs, RhoB is increased and cells die,” he says.

The study was possible because Dr. Copland and his laboratory colleagues, including co-author Laura Marlow, created and characterized two new ovarian laboratory cell lines. They were derived from tumor tissue specimens taken from a patient with metastatic cancer whose tumors had stopped responding to multiple chemotherapy drugs.

Dr. Colon-Otero suggested trying the two drugs on the new cells lines. Neither drug is approved for use in ovarian cancer. Ixabepilone is a chemotherapy drug that, like other taxane drugs, targets the microtubules and stops dividing cells from forming a spindle. It has been approved for use in metastatic breast cancer. Sunitinib, approved for use in kidney cancer, belongs to a class of tyrosine kinase inhibitors that stops growth signals from reaching inside cancer cells.

Prakash Vishnu, M.D., a former fellow at Mayo Clinic in Florida who is now at the Floyd and Delores Jones Cancer Institute in Virginia Mason Medical Center, Seattle, is the first author of the article and led the study under the mentorship of Drs. Colon-Otero and Copland. He found that in both cell lines, cell kill was significantly greater with the combination than use of either drug alone. For example, in chemotherapy-resistant lines (where this potential combination therapy will most likely be used), ixabepilone alone killed up to 30 percent of cells, and the rate for suntinib was up to 10 percent. When the agents were used together, the kill rate was 70 percent.

Dr. Copland said that RhoB is a potential biomarker that may help identify patients who might benefit from such combination therapy.

“Ovarian cancer is a deadly disease. If we are to improve outcome for patients, it is essential that we develop tools to support biologically-informed clinical decision-making” said Johnathan Lancaster, MD, PhD, Director of Center for Women’s Oncology at the Moffitt Cancer Center.  ”As such, we are excited about our new partnership with OvaGene. It will enable us to accelerate our microRNA laboratory findings towards the clinic, as personalized medicine tools that may benefit patients in the near-term.”

“We are delighted to partner with a molecular diagnostics company dedicated to taking important technologies from the bench to the bedside,” said Haskell Adler PhD MBA, Senior Licensing Manager at the Moffitt Cancer Center.  ”Because of the shared vision between our two organizations, we are optimistic this is the beginning of a long and fruitful relationship involving a number of technologies developed here at Moffitt.”

The technology, licensed from The Moffitt Cancer Center, includes proprietary microRNA-based biomarkers that can be used to predict response to chemotherapy in a variety of tumor types. Initially, OvaGene intends to develop a specific microRNA-based profile to predict drug response in advanced ovarian cancer.   Following the development of the ovarian cancer assay, OvaGene will focus on creating additional assays for drug response in a variety of gynecologic cancers and pursue strategic partnerships to develop similar profiles in other tumor types.  Developmental studies, CLIA lab validation, and subsequent commercialization are expected to occur over the next eighteen to twenty-four months.

“We are looking forward to developing and commercializing the very first cancer microRNA diagnostic assay related to drug response,” said William Ricketts, PhD, OvaGene Chief Scientific Officer. “We are at the forefront of molecular diagnostic development for gynecologic cancers and we are excited about the innovative and clinically useful microRNA drug response panels we will be bringing to market”

Scientists at the Edinburgh Cancer Research UK Centre at the University of Edinburgh removed a protein called FAK from mice and from cancer cells grown in the lab. FAK is produced in much higher amounts in cancer cells and partners with another protein, SRC. They work together to cause the tumour to grow and spread.

But the team discovered that cancer cells then get rid of the problematic SRC protein – and survive. Cancer cells use a process called autophagy to bag up and digest excess SRC.  Essentially the cells have hijacked a normal housekeeping process, normally used to digest proteins and recycle nutrients.

The cancer cells placed a protective membrane around the excess SRC and filled them with chemicals to break up and recycle the contents. It was not previously known that cancer cells could dispose of the toxic SRC protein this way, but they do.

The research suggests that blocking FAK, while also stopping cells disposing of SRC, may provide a powerful new route to destroy cancer cells.

“We’ve shown that cancer cells can adapt to the problems caused by stress, by hijacking normal cell waste disposal to ‘bag up and bin’ toxic proteins” said author Professor Margaret Frame. “This reveals a previously unknown weak spot in cancer cells – and a potential new pathway to tackle cancer.

“Combining drugs already in development, which block FAK, with techniques to stop cancer cells removing excess toxic SRC, would kill them.”

Dr Julie Sharp, Cancer Research UK’s senior science communications manager, said: “When healthy cells get old or get injured they automatically commit suicide so that mistakes can’t be passed on to new cells. But cancer cells have found various ways to continue to grow and divide.
“Thanks to the generosity of the public’s support we’re able to invest in world-leading research such as this. By learning more about how cancer cells cheat death, we hope we’ll discover new ways to prevent and treat the disease.”

Autophagic targeting of Src promotes cancer cell survival following reduced FAK signalling

The findings are reported online in the journal Cancer Research. : Finding a Panacea Among Combination Cancer Therapies

“The goal of targeted therapy is to stop the growth of cancerous cells while doing little or no harm to healthy tissue,” said Guy Perkins, PhD, associate project scientist at the Center for Research in Biological Systems at UC San Diego. “Cancer researchers are always looking for new therapies to target a variety of cancers and kill tumor cells in various stages of development.”

Unfortunately, added co-author Ryuji Yamaguchi, PhD, senior researcher at Kyushu University Medical School in Fukuoka, Japan, “even the best new drugs seem to be limited to specific cancer types and too often tumor cells develop resistance to these drugs, leading to eventual treatment failure.”

The new two-part therapy described by Perkins and Yamaguchi focuses on depriving cancer cells of their fundamental need for sugar to fuel growth and multiplication. The first component is a modified glucose or sugar molecule called 2-deoxyglucose (2-DG). Although readily taken in by sugar-hungry cancer cells, it cannot be broken down to produce energy. Instead, it hampers cancer cell growth and primes the cells for early death by opening access to an internal protein that can trigger apoptosis.

Cells primed with 2-DG are then exposed to a pair of drugs, ABT-263/737, which signal the internal protein to initiate cell death. Researchers say only cancer cells sensitized for death by 2-DG and exposed to ABT-263/737 are broadly impacted. Healthy brain cells, which are also highly glycolytic like cancer cells, are protected because ABT-263/737 cannot cross the body’s blood-brain barrier.

After first determining that in vitro cancer cells incubated with 2-DG and exposed to low concentrations of ABT-263/737 died, the researchers conducted animal studies. They found that when 2-DG was injected into animals, it predominantly accumulated in cancer cells that were subsequently killed by an injection of ABT-263/737. The two-step approach successfully induced apoptosis in leukemia, hepatocarcinoma, lung, breast and cervical cancers. Yamaguchi said it caused cell death at many stages of cancer development, including a difficult-to-treat, chemo-resistant, highly metastasized form of prostate cancer.

“Since the combination of 2-DG and ABT-263/737 induces rapid apoptosis through the intrinsic pathway, meaning through mitochondria, it leaves little room for interference by a cancer cell’s highly active mutagenic programs,” Perkins said.

The combined treatment, however, does not work on all cancers. “There are certain cancers that are resistant or in which this would cause lymphopenia and thrombopenia,” said Yamaguchi. Lymphopenia and thrombopenia are a loss of white blood cells or platelets, respectively. The scientists are developing “workarounds” to counteract these adverse effects, possibly by using stored hematopoietic stem cells for transplant after treatment.

“We are now trying to initiate a clinical trial for the combination,” said Yamaguchi. “Since both 2-DG and ABT-263 (Navitoclax) are already in Phase II clinical trials (for other treatments), we know something about the safety of these agents. Once we take precautionary measures, the 2-DG-ABT combination therapy may prove an effective alternative to some existing cancer therapies. We may have found a simple, partial solution to a very complex disease.”

Done in mouse models, the study serves as first proof-of-principle that blood stem cells, which make every cell type found in blood, can be genetically altered in a living organism to create an army of melanoma-fighting T-cells, said Jerome Zack, study senior author and a scientist with UCLA’s Jonsson Comprehensive Cancer Center and the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research.

“We knew from previous studies that we could generate engineered T-cells, but would they work to fight cancer in a relevant model of human disease, such as melanoma,” said Zack, a professor of medicine and microbiology, immunology, and molecular genetics in Life Sciences. “We found with this study that they do work in a human model to fight cancer, and it’s a pretty exciting finding.”

The study appears Nov. 28, 2011 in the early online edition of Proceedings of the National Academy of Sciences. Antitumor activity from antigen-specific CD8 T cells generated in vivo from genetically engineered human hematopoietic stem cells

Researchers used a T-cell receptor from a cancer patient cloned by other scientists that seeks out an antigen expressed by this type of melanoma. They then genetically engineered the human blood stem cells by importing genes for the T-cell receptor into the stem cell nucleus using a viral vehicle. The genes integrate with the cell DNA and are permanently incorporated into the blood stem cells, theoretically enabling them to produce melanoma-fighting cells indefinitely and when needed, said Dimitrios N. Vatakis, study first author and an assistant researcher in Zack’s lab.

“The nice thing about this approach is a few engineered stem cells can turn into an army of T-cells that will respond to the presence of this melanoma antigen,” Vatakis said. “These cells can exist in the periphery of the blood and if they detect the melanoma antigen, they can replicate to fight the cancer.”

In the study, the engineered blood stem cells were placed into human thymus tissue that had been implanted in the mice, allowing Zack and his team to study the human immune system reaction to melanoma in a living organism. Over time, about six weeks, the engineered blood stem cells developed into a large population of mature, melanoma-specific T-cells that were able to target the right cancer cells.

The mice were then implanted with two types of melanoma, one that expressed the antigen complex that attracts the engineered T-cells and one tumor that did not. The engineered cells specifically went after the antigen-expressing melanoma, leaving the control tumor alone, Zack said.

The study included nine mice. In four animals, the antigen-expressing melanomas were completely eliminated. In the other five mice, the antigen-expressing melanomas decreased in size, Zack said, an impressive finding.