FDA Awards $1.6M Orphan Drug Grant for Clinical Phase II Development of EGEN-001 for Treatment of Ovarian Cancer

EGEN, Inc. announced that the Food and Drug Administration (FDA) awarded the company a four-year grant of $1.6 million to assist in the phase II clinical development of EGEN-001, the company’s lead product. EGEN-001 is under clinical development for the treatment of advanced recurrent ovarian cancer.

EGEN, Inc. announced that the Food and Drug Administration (FDA) awarded the company a four-year grant of $1.6 million to assist in the phase II clinical development of EGEN-001, the company’s lead product. EGEN-001 is under clinical development for the treatment of advanced recurrent ovarian cancer.[1]

EGEN, Inc. is developing gene-based biopharmaceuticals that rely on proprietary delivery technologies such as TheraPlas™ (illustrated above). In preclinical studies, the application of this approach produced anti-cancer activity in the treatment of disseminated abdominal cancers, solid tumors and metastatic cancers. (Photo: EGEN, Inc.)

EGEN-001 was developed as an interleukin-12 (IL‑12) gene therapy for the treatment of disseminated epithelial ovarian cancer. It is a low concentration formulation composed of a human IL-12 plasmid formulated with a proprietary PPC delivery system. EGEN-001 is designed for intraperitoneal (IP) administration. The subsequent IL-12 protein expression is associated with an increase in immune system activity, including T-lymphocyte and natural killer (NK) cell proliferation, and cytotoxic activation and secretion of interferon gamma (IFN-g), which in turn, leads to tumor inhibition. Additionally, IL-12 inhibits angiogenesis and formation of tumor vascularization.

EGEN has successfully completed two Phase I trials of EGEN-001 in ovarian cancer patients.  In the first study, EGEN-001 was administered as monotherapy in platinum-resistant ovarian cancer patients[2] and in the second study in combination with carboplatin/docetaxel chemotherapy in platinum-sensitive ovarian cancer patients.[3] In both studies, EGEN-001 treatment resulted in good safety, biological activity and encouraging efficacy.[4-5] EGEN-001 received Orphan Drug Status from the FDA in 2005, and its first $1 million FDA orphan grant in 2005.

“This is a significant milestone and accomplishment for the company,” commented Dr. Khursheed Anwer, President and Chief Science Officer of EGEN. “We are pleased to receive this FDA support, which has been very useful in the advancement of our novel EGEN-001 product in the clinic for the treatment of recurrent ovarian cancer. The product utilizes the Company’s proprietary TheraPlas® delivery technology and is composed of interleukin-12 (IL-12) gene formulation with a biocompatible delivery polymer. IL-12 is a potent cytokine which works by enhancing the body’s immune system against cancer and inhibiting tumor blood supply.”

About EGEN, Inc.

EGEN, Inc. (EGEN), with laboratories and headquarters in Huntsville, Alabama, is a privately held biopharmaceutical company focused on developing therapeutics for the treatment of human diseases including cancer. The Company specializes in the delivery of therapeutic nucleic acids (DNA and RNAi) and proteins aimed at specific disease targets. The Company has a significant intellectual property position in synthetic carriers, their combination with DNA, and their therapeutic applications. EGEN’s research pipeline products are aimed at treatment of various cancer indications. In addition, the Company has its TheraSilence® delivery technology aimed at delivery of therapeutic siRNA for the treatment of human diseases. EGEN collaborates with outside investigators, biotech organizations, and universities on various projects in these areas.

References:

1/ A Phase II Evaluation of Intraperitoneal EGEN-001 (IL-12 Plasmid Formulated With PEG-PEI-Cholesterol Lipopolymer) in the Treatment of Persistent or Recurrent Epithelial Ovarian, Fallopian Tube or Primary Peritoneal Cancer, Clinical Trial Summary, ClinicialTrials.gov (Identifier:  NCT01118052).

2/A Phase 1, Open Label, Dose Escalation Study of the Safety, Tolerability and Preliminary Efficacy of Intraperitoneal EGEN-001 in Patients With Recurrent Epithelial Ovarian Cancer, Clinical Trial Summary, ClinicialTrials.gov (Identifier: NCT00137865).

3/A Phase 1, Open-Label, Dose Escalation Study of the Safety and Preliminary Efficacy of EGEN-001 in Combination With Carboplatin and Docetaxel in Women With Recurrent, Platinum-Sensitive, Epithelial Ovarian Cancer, Clinical Trial Summary, ClinicialTrials.gov (Identifier:  NCT00473954).

4/Kendrick JE, Matthews KS, Straughn JM, et. al.  A phase I trial of intraperitoneal EGEN-001, a novel IL-12 gene therapeutic, administered alone or in combination with chemotherapy in patients with recurrent ovarian cancer.  J Clin Oncol 26: 2008 (May 20 suppl; abstr 5572).

5/Anwar K, Barnes MN, Kelly FJ, et. al. Safety and tolerability of a novel IL-12 gene therapeutic administered in combination with carboplatin/docetaxel in patients with recurrent ovarian cancer.  J Clin Oncol 28:15s, 2010 (suppl; abstr 5045).

Source: FDA Awards EGEN, Inc. Orphan -Drug Grant for Clinical Development of EGEN-001 for Treatment of Ovarian Cancer, Press Release, EGEN, Inc., February 2, 2011.

Disarming Specialized Stem Cells Might Combat Ovarian Cancer

Eliminating cancer stem cells (CSCs) within a tumor could hold the key to successful treatments for ovarian cancer, which has been notoriously difficult to detect and treat, according to new findings published this week in the journal Oncogene by Yale School of Medicine researchers.

Eliminating cancer stem cells (CSCs) within a tumor could hold the key to successful treatments for ovarian cancer, which has been notoriously difficult to detect and treat, according to new findings published this week in the journal Oncogene by Yale School of Medicine researchers.

“We found that stopping the expression of two genesLin28 and Oct4—reduces ovarian cancer cell growth and survival,” said Yingqun Huang, M.D., Ph.D., assistant professor in the Department of Obstetrics, Gynecology & Reproductive Sciences at Yale School of Medicine.

Ovarian cancer is challenging to treat because it tends to recur frequently and develop resistance to treatment. The poor outcome for women with ovarian cancer is associated with subtle and nonspecific symptoms—earning it the moniker the “disease that whispers.”

“This recurrence and drug resistance may be due to the presence of CSCs within the tumors that have the capacity to reproduce and to differentiate into non-CSC tumor cells that repopulate the tumor mass,” said Huang, who is a member of Yale Stem Cell Center and Yale Cancer Center. “Eliminating these CSCs may be key to successful treatments.”

While in the process of studying the functions of stem cell proteins in human embryonic stem cells, Huang and her colleagues unexpectedly discovered that a sub-population of ovarian cancer cells express stem cell proteins Lin28 and Oct4. They also found that the two proteins appear to act together in ovarian cancer tissue cells to produce more advanced tumors. Inhibiting their combined expression led to a significant decrease in the growth and survival of cancer cells. A larger-scale ovarian cancer study is currently underway to confirm the significance of the findings.

Genetic researchers prevent genes from functioning — a process commonly referred to as “knocking down” the gene — by inserting small interfering RNA (siRNA) molecules into the cells. Next, the research team will examine the effect of siRNA in ovarian cancer cells in the lab, and test the technique on mice. If successful, human clinical trials would follow. Treatment on cancer patients could occur within 10 years, Huang said.

“We hope we will soon be able to apply this new information to improve outcomes, perhaps by developing better diagnostic markers and treatment strategies that may be useful in customizing treatment for ovarian cancer patients,” said Huang.

The study was supported by Connecticut Innovations, the Fannie E. Rippel Foundation and the National Cancer Institute.

Other Yale authors on the study included Nita Maihle, Ph.D., and Shuping Peng.

Sources:

Trojan Horse* For Ovarian Cancer–Nanoparticles Turn Immune System Soldiers Against Tumor Cells

In a feat of trickery, Dartmouth Medical School immunologists have devised a Trojan horse to help overcome ovarian cancer, unleashing a surprise killer in the surroundings of a hard-to-treat tumor. Using nanoparticles–ultra small bits– the team has reprogrammed a protective cell that ovarian cancers have corrupted to feed their growth, turning the cells back from tumor friend to foe. Their research, published online July 13 for the August Journal of Clinical Investigation, offers a promising approach to orchestrate an attack against a cancer whose survival rates have barely budged over the last three decades …

Hanover, N.H.—In a feat of trickery, Dartmouth Medical School immunologists have devised a Trojan horse to help overcome ovarian cancer, unleashing a surprise killer in the surroundings of a hard-to-treat tumor.

Using nanoparticles–ultra small bits– the team has reprogrammed a protective cell that ovarian cancers have corrupted to feed their growth, turning the cells back from tumor friend to foe. Their research, published online July 13 for the August Journal of Clinical Investigation, offers a promising approach to orchestrate an attack against a cancer whose survival rates have barely budged over the last three decades.

Dr. Jose Conejo-Garcia (right) with graduate student Juan Cubillos-Ruiz  (Photo Source:  Dartmouth Medical School News Release,

Dr. Jose Conejo-Garcia (right) with graduate student Juan Cubillos-Ruiz (Photo Source: Dartmouth Medical School News Release, 13 Jul. 09)

“We have modulated elements of the tumor microenvironment that are not cancer cells, reversing their role as accomplices in tumor growth to attackers that boost responses against the tumor,” said Dr. Jose Conejo-Garcia, assistant professor of microbiology and immunology and of medicine, who led the research. “The cooperating cells hit by the particles return to fighters that immediately kill tumor cells.”

The study, in mice with established ovarian tumors, involves a polymer now in clinical trials for other tumors. The polymer interacts with a receptor that senses danger to activate cells that trigger an inflammatory immune response.

The Dartmouth work focuses on dendritic cells–an immune cell particularly abundant in the ovarian cancer environment. It does take direct aim at tumor cells, so it could be an amenable adjunct to other current therapies.

“The cooperating cells hit by the particles return to fighters that immediately kill tumor cells.” —Dr. Jose Conejo-Garcia

“That’s the beautiful part of story–people usually inject these nanoparticles to target tumor cells. But we found that these dendritic cells that are commonly present in ovarian cancer were preferentially and avidly engulfing the nanoparticles. We couldn’t find any tumor cells taking up the nanoparticles, only the dendritic cells residing in the tumor,” explained Juan R. Cubillos-Ruiz, graduate student and first author.

Dendritic cells are phagocytes–the soldiers of the immune system that gobble up bacteria and other pathogens, but ovarian cancer has co-opted them for its own use, he continued. “So we were trying to restore the attributes of these dendritic cells–the good guys; they become Trojan horses.”

Cancer is more than tumor cells; many other circulating cells including the dendritic phagocytes converge to occupy nearby space. The dendritic cells around ovarian cancer scoop up the nanocomplexes, composed of a polymer and small interfering RNA (siRNA) molecules to silence their immunosuppressive activity.

Nanoparticle incorporation transforms them from an immunosuppressive to an immunostimulatory cell type at tumor locations, provoking anti-tumor responses and also directly killing tumor cells. The effect is particularly striking with an siRNA designed to silence the gene responsible for making an immune protein called PD-L.

The new findings also raise a warning flag about the use of gene silencing complexes in cancer treatment. Inflammation is a helpful immune response, but the researchers urge caution when using compounds that can enhance inflammation in a patient already weakened by cancer.

Ovarian cancer, which claims an estimated 15,000 US lives a year, is an accessible disease for nanoparticle delivery, according to the investigators. Instead of systemic administration, complexes can be put directly into the peritoneal cavity where the phagocytes take them up.

Samples of human ovarian cancer cells show similar responses to nanoparticle stimulation, the researchers observed, suggesting feasibility in the clinical setting. It could be part of a “multimodal approach,” against ovarian cancer, said Conejo-Garcia also a member of the Dartmouth’s Norris Cotton Cancer Center. “The prevailing treatment is surgical debulking, followed by chemotherapy. Our findings could complement those because they target not the tumor cells themselves, but different cells present around the tumor.”

Co-authors are Xavier Engle, Uciane K. Scarlett, Diana Martinez, Amorette Barber, Raul Elgueta, Li Wang, Yolanda Nesbeth and Charles Sentman of Dartmouth; Yvon Durant of University of New Hampshire, Andrew T Gewirtz of Emory, and Ross Kedl of University of Colorado.

The work was supported by grants from the National Institutes of Health, including the National Cancer Institute and National Center for Research Resources, a Liz Tilberis Award from the Ovarian Cancer Research Fund, and the Norris Cotton Cancer Center Nanotechnology Group Award.

Read an interview of Jose Conejo – Garcia with the Ovarian Cancer Research Fund.

Source: Trojan Horse for Ovarian Cancer–Nanoparticles Turn Immune System Soldiers against Tumor Cells, News Release, Dartmouth Medical School, July 13, 2009 (summarizing Cubillos-Ruiz JR, Engle X, Scarlett UK, et. al. Polyethylenimine-based siRNA nanocomplexes reprogram tumor-associated dendritic cells via TLR5 to elicit therapeutic antitumor immunity. J Clin Invest. 2009 Aug 3;119(8):2231-2244. doi: 10.1172/JCI37716. Epub 2009 Jul 13).

__________________

* The Trojan Horse was a tale from the Trojan War, as told in Virgil’s Latin epic poem The Aeneid. The events in this story from the Bronze Age took place after Homer’s Iliad, and before Homer’s Odyssey. It was the strategy that allowed the Greeks finally to enter the city of Troy and end the conflict. In the best-known version, after a fruitless 10-year siege of Troy, the Greeks built a huge horse figure and hid a select force of men within it. The Greeks left the Horse at the city gates of Troy and pretended to sail away.  Thereafter, the Trojans pulled the Horse into their city as a victory trophy. That night the Greek force crept out of the Horse and opened the gates for the returning Greek army, which had sailed back to Troy under cover of night. The Greek army entered and destroyed the city, decisively ending the war. A “Trojan Horse” has come to mean any trick that causes a target to invite a foe into a securely protected bastion or place.

A Potential Treatment For Ovarian Cancer – Claudin-3 Gene Silencing Using Small Interfering RNA

“… Ovarian tumors highly express two proteins, claudin-3 and -4. These proteins are associated with both an increase is cellular motility and survival of ovarian tumor cells.  Claudin-3 is also over expressed in breast and prostate tumors. This new therapy is targeting claudin-3 (CLDN3) using small interfering RNA (siRNA). More specifically, this team has developed a nanoparticulate, lipid-like delivery system for intraperitoneal delivery of siRNA to ovarian tumors. Tests of the therapeutic efficacy of CLDN3 siRNA in three different mouse models showed a significant reduction in tumor growth.  Additionally, these mice showed no ill side effects of the CLDN3 siRNA treatment. …”

“PAPER REVEALS POTENTIAL NEW TREATMENT FOR OVARIAN CANCER

Wynnewood, PA, February 9, 2009 – – – – – Ovarian cancer is the fourth most common cancer in women and has the highest mortality rate for gynecologic cancers because it is often diagnosed at an advanced stage. New effective therapies for the treatment of advanced stage ovarian cancer are urgently needed.

Today, a paper published in the Proceedings of the National Academy of Sciences (PNAS) by Dr. Janet Sawicki, Professor at the Lankenau Institute for Medical Research (LIMR), a team headed by Daniel G. Anderson, Ph.D. and Robert Langer, Sc.D. of the David H. Koch Institute for Integrative Cancer Research at the Massachusetts Institute of Technology (MIT) and David Bumcrot, Director of Research at Alnylam Pharmaceuticals, shows that a new therapy suppresses ovarian tumor growth and metastasis in preclinical studies.

Ovarian tumors highly express two proteins, claudin-3 and -4. These proteins are associated with both an increase is cellular motility and survival of ovarian tumor cells.  Claudin-3 is also over expressed in breast and prostate tumors. This new therapy is targeting claudin-3 (CLDN3) using small interfering RNA (siRNA). More specifically, this team has developed a nanoparticulate, lipid-like delivery system for intraperitoneal delivery of siRNA to ovarian tumors. Tests of the therapeutic efficacy of CLDN3 siRNA in three different mouse models showed a significant reduction in tumor growth.  Additionally, these mice showed no ill side effects of the CLDN3 siRNA treatment.

‘We are excited by the preclinical performance of these formulations, and are hopeful that the lipidoid-siRNA nanoparticulates developed here may enable new genetic therapies for ovarian cancer,’ said Anderson.

‘These findings offer new hope for a therapeutic treatment option for individuals with metastatic ovarian cancer and potentially other types of cancers that over-express CLDN3’, states Dr. Janet Sawicki.  ‘Our next step is to begin Phase I clinical trials to test for safety with hopes to bring this treatment to the patient in the next few years.’

This research was made possible through funding from the National Institutes of Health (NIH), the Sandy Rollman Ovarian Cancer Foundation of Havertown, PA, and Wawa.

Lankenau Institute for Medical Research
Founded in 1927, the Lankenau Institute for Medical Research (LIMR) is an independent, nonprofit biomedical research center located in suburban Philadelphia on the campus of the Lankenau Hospital. As part of the Main Line Health System, LIMR is one of the few freestanding, hospital-associated medical research centers in the nation.  The faculty and staff at the Institute are dedicated to advancing an understanding of the causes of cancer and heart disease. They use this information to help improve diagnosis and treatment of these diseases as well as find ways to prevent them. They are also committed to extending the boundaries of human health and well-being through technology transfer and education directed at the scientific, clinical, business and lay public communities. For more information visit: http://www.limr.org.

David H. Koch Institute for Integrative Cancer Research at MIT
Launched by MIT in 2008, the David H. Koch Institute for Integrative Cancer Research (KI) both transforms and transcends the Center for Cancer Research (CCR). CCR was founded in 1974 by Nobel Laureate and MIT Professor Salvador Luria, CCR has made enormous contributions to the field of cancer research. The Koch is one of only seven National Cancer Institute-designated basic research centers in the US and is comprised of faculty that have earned the most prestigious national and international science honors including the Nobel Prize and the National Medal of Science. For more information visit: web.mit.edu/ki/index.html.

Alnylam Pharmaceuticals, Inc.
Alnylam Pharmaceuticals, a leader in RNAi therapeutics, is a biopharmaceutical company developing novel therapeutics based on a breakthrough in biology known as RNA interference, or RNAi; a discovery that enables the creation of a broad new class of human therapeutics. Using RNAi, Alnylam has built a product engine to develop a deep pipeline of drug products to treat a wide array of important diseases. For more information visit: http://www.alnylam.com

Contact: Tava Shanchuk
Phone: (610) 645-3429
E-mail: shanchukt@mlhs.org”

RNA Interference Primer – Alnylam Pharmaceuticals

Quoted Source Paper Reveals Potential New Treatment for Ovarian Cancer, Press Release, Lankenau Institute for Medical Research, Feb. 9, 2009.

Primary CitationClaudin-3 gene silencing with siRNA suppresses ovarian tumor growth and metastasis; Huang YH, Bao Y, Peng W et. al., Proc Natl Acad Sci U S A. 2009 Feb 10. [Epub ahead of print]

Additional Resources:

M.D. Anderson Identifies TG2 As a Potential Target in Chemo-Resistant Ovarian Cancer

“Scientists from The University of Texas M. D. Anderson Cancer Center have found overexpression of tissue type transglutaminase (TG2) in ovarian cancer is associated with increased tumor cell growth and adhesion, resistance to chemotherapy and lower overall survival rates. When researchers targeted and silenced TG2 in animal models, cancer progression was reversed, suggesting the protein may also provide a novel therapeutic approach for late-stage ovarian cancer.”

“Scientists from The University of Texas M. D. Anderson Cancer Center have found overexpression of tissue type transglutaminase (TG2) in ovarian cancer is associated with increased tumor cell growth and adhesion, resistance to chemotherapy and lower overall survival rates. When researchers targeted and silenced TG2 in animal models, cancer progression was reversed, suggesting the protein may also provide a novel therapeutic approach for late-stage ovarian cancer.

These findings in the July 15th issue of Cancer Research by a team of researchers led by Anil K. Sood, M.D., professor in the Departments of Gynecologic Oncology and Cancer Biology, and Kapil Mehta, Ph.D., professor in the Department of Experimental Therapeutics at M. D. Anderson, are among the first to explore TG2’s functionality in ovarian cancer.

‘TG2 appears to fuel different types of cancer through multiple molecular pathways, making it an important therapeutic target,’ said Mehta, whose lab also has connected TG2 overexpression to drug-resistant and metastatic melanoma, breast cancer and pancreatic cancer.

‘Drug resistance and metastasis are major impediments to the successful treatment of ovarian cancer and until now we had little information about the role TG2 played in ovarian cancer,’ Sood said. ‘We began to see its story unfold as we translated this data from tissue samples to cell lines to animal models.’

The American Cancer Society estimates 15,000 U.S. women will die from ovarian cancer this year. Most patients present with advanced stage disease that has spread beyond the primary tumor site. More than 70 percent of ovarian cancer patients will suffer a recurrence and eventually succumb to the disease.

Higher TG2, lower survival

The study, which examined 93 ovarian cancer samples of ranging stages, found that high levels of TG2 corresponded with significantly lower patient survival than those with low levels of TG2. Sixty-nine percent of high-stage ovarian cancers overexpressed TG2 compared with 30 percent of low-stage cancers. In-depth analysis demonstrated that tumors which overexpressed the protein tended to have an increased ability to invade healthy tissue and to survive or avoid the affects of chemotherapy.

‘From this investigation it became clear that TG2 activates the survival pathway p13K/Akt in these tumors, explaining the adverse, resistant behavior we observed on a molecular level,’ said Sood. ‘We then focused on whether silencing TG2 would block these effects.’

Researchers shut off TG2 with a small interfering RNA strand (TG2 siRNA) targeted to the protein, reducing the ability of the tumor cells to invade and killing them through programmed cell death, or apoptosis. ‘When exposed to this potent targeted therapy, ovarian cancer cells greatly reduced cancer cell proliferation and blood vessel development, while increasing apoptosis,’ said Sood.

Mouse model studies of chemotherapy-sensitive and chemotherapy-resistant models showed considerable antitumor activity both with TG2 siRNA alone and in combination with docetaxel chemotherapy. The combination therapy of TG2 siRNA with docetaxel reduced tumor weight by 86 percent, proving to have the greatest efficacy compared to control groups or those without chemotherapy.

‘While it remains to be seen if these results will translate in humans, looking ahead long term, it will be an attractive option against advanced ovarian cancer,’ said co-author Gabriel Lopez-Berestein, M.D. professor in the Department of Experimental Therapeutics at M. D. Anderson.

TG2 fuels pancreatic cancer differently

Sood and Lopez-Berestein, have developed siRNA therapy by packaging the gene-silencing strips of RNA in a fatty nanoparticle called a liposome and delivering it intravenously. TG2 is the third protein they have targeted in preclinical research. Sood and Mehta are moving TG2 siRNA toward Phase I clinical trials for ovarian and pancreatic cancers.

TG2 acts through different pathways in other types of cancer, Mehta noted. For example, TG2 overexpression causes the degradation of the tumor-suppressing protein PTEN in pancreatic cancer, Mehta and colleagues reported in Clinical Cancer Research in April. With PTEN out of the picture, pancreatic cancer is protected from a separate type of cell death called autophagy. In a separate paper, they showed that silencing TG2 with the siRNA liposome reduced tumor size, slowed metastasis and enhanced the effect of gemcitabine chemotherapy.

‘This aberrant protein is doing so many different things, you would have to develop a small-molecule drug to block each function,’ Mehta said. ‘Liposomal siRNA is exciting because it takes out TG2 completely, blocking everything that it does.’

Research was funded by grants from the National Cancer Institute, including M. D. Anderson’s Specialized Program in Research Excellence in Ovarian Cancer grant, a program project development grant from the Ovarian Cancer Research Fund, Inc., and the Zarrow Foundation.

In addition to Sood, Mehta and Lopez-Berestein, authors include Jee Young Hwang, M.D., Lingegowda S. Mangala, Ph.D., co-first authors, and Yvonne G. Lin, M.D., William M. Merritt, M.D., Whitney A. Spannuth, M.D., Alpa M. Nick, M.D., Derek J. Fiterman, M.D., and Robert L. Coleman, M.D., all of M. D. Anderson’s Department of Gynecologic Oncology; Jansina Y. Fok, also a co-first author, and Pablo E. Vivas-Mejia, Ph.D., both of the Department of Experimental Therapeutics; and Michael T. Deavers, M.D., of M. D. Anderson’s Department of Pathology. Hwang is also with the Department of Obstetrics and Gynecology, Dongguk University of College of Medicine, Kyung-ju, Korea. 07/15/08”

Quoted Source: TG2 Identified as Potential Target in Chemo-Resistant Ovarian Cancer – M. D. Anderson team silences protein with siRNA, implicates TG2 in fourth cancer, The University of Texas, M.D. Anderson Cancer Center News Release, July 15, 2008 (summarizing the findings of Clinical and biological significance of tissue transglutaminase in ovarian carcinoma; Sood, AK et. al,  Cancer Res. 2008 Jul 15;68(14):5849-58.)

Additional Information:

Liposomal siRNA — Genetic On/Off Switches That Target Ovarian Cancer Through the Trojan Horse Effect

Use of Liposomal siRNA to Target Ovarian Cancer Protein Known as “Interleukin-8 (IL-8)”

“A protein that stimulates blood vessel growth worsens ovarian cancer, but its production can be stifled by a tiny bit of RNA wrapped in a fatty nanoparticle, a research team led by scientists at The University of Texas M. D. Anderson Cancer Center reports in the Journal of the National Cancer Institute.

The protein IL-8 is a potential therapeutic target in ovarian cancer,’ said senior author Anil Sood, M.D., professor in the M. D. Anderson Departments of Gynecologic Oncology and Cancer Biology.

The paper demonstrates that high IL-8 expression in tumors is associated with advanced tumor stage and earlier death for ovarian cancer patients. Lab experiments and research in a mouse model show that short interfering RNA (siRNA) can cut IL-8 expression, reducing tumor size by attacking its blood supply.

‘This comprehensive analysis – with human data, animal data and lab experiments to highlight the molecular mechanisms involved – helps us develop the new targets needed for a more effective approach against ovarian cancer,’ Sood said.

Interleukin-8 is overexpressed in many types of cancer and has previously been shown to promote tumor growth, new blood vessel growth known as angiogenesis, and metastasis, the spread of cancer to other organs. ‘In the long run, this research will have applications in other cancers as well,’ Sood said.

His research focuses on ovarian cancer, for example, while senior co-author Menashe Bar-Eli, Ph.D., professor in M. D. Anderson’s Department of Cancer Biology, examines IL-8’s role in melanoma.

Impact on survival

Ovarian cancer is often detected in late stages. Initial treatment includes surgery and taxane- or platinum-based chemotherapy regimens that keep the cancer at bay for a time in most patients. Recurrence is common and often lethal.

To examine IL-8’s role in ovarian cancer, the researchers analyzed tumors from 102 patients diagnosed and treated between 1988 and 2006 at M. D. Anderson and the University of Iowa. Of those, 43 had tumors with high levels of IL-8 and 59 had low levels. The median survival of those with high IL-8 tumors was 1.62 years, compared with 3.79 years for those with low expression of the protein.

All 43 tumors with high expression of IL-8 were of high grade and 42 of 43 were advanced, either stage III or IV tumors. By comparison, 10 of 59 tumors with low IL-8 expression were early stage tumors and six were of low grade.

Shrinking tumors

Genes transcribe single strands of RNA that in turn are ‘read’ by ribosomes to produce proteins. siRNAs are short, double-stranded bits of RNA capable of halting that process. The team confirmed in a lab experiment that a specific siRNA silences IL-8 and then tested it against two lines of ovarian cancer in a mouse model.

Sood, Gabriel Lopez-Berestein, M.D., professor in M. D. Anderson’s Department of Experimental Therapeutics, and colleagues are building an arsenal of siRNAs capable of silencing genes that produce cancer-promoting proteins. They packaged siRNA that stymies IL-8 into a small ball of fat known as a liposome, a combination they developed to overcome a problem – siRNA is hard to deliver to tumors.

Tumors shrank by a median of 32 percent and 52 percent in the two cancer lines among mice that received injections of the IL-8 siRNA liposome compared to those receiving control siRNA or empty liposomes.

Mice that got both the IL-8 siRNA plus the taxane-based chemotherapy drug docetaxel [Taxotere®] had median tumor weight reduction of 90 percent and 98 percent in the two cell lines. Mice with control siRNA plus docetaxel saw reductions of 67 and 84 percent.

Finally, they tested the approach in mice with an ovarian cancer cell line known to be resistant to taxane-based drugs such as docetaxel. IL-8 siRNA alone reduced the size of these tumors by 47 percent, and when combined with docetaxel reduced tumor size by 77 percent, suggesting that the combination re-sensitizes a resistant tumor to taxanes.

The team gauged the impact of IL-8 siRNA on tumor blood supply by measuring the density of blood vessels in the tumor. The IL-8 siRNA alone reduced blood vessel density by 34 percent and 39 percent in two cancer lines.

Clinical Prospects

‘These are encouraging results. We want to move one of our siRNA agents into the clinic to test its potential for therapy,’ Sood said, ‘and then in the longer term, we’ll consider moving additional siRNA agents into the clinical arena.’

The IL-8 siRNA liposome is the third developed by Sood’s and Lopez-Berestein’s team. Two others target the oncoproteins FAK and EphA2. The EphA2 siRNA liposome is closest to Phase I clinical trial, with required toxicology studies nearly complete. A clinical trial could begin within a year.

Methods used to inject siRNA in high volumes for research purposes are impractical for human therapy. Sood and Lopez-Berestein developed the liposomal approach to ensure that the siRNA reaches the cell intact so it can silence the targeted gene. Their research has shown that the liposome penetrates deeply into cells to deliver its siRNA.

Research reported in JNCI was funded by grants from the National Cancer Institute of the National Institutes of Health, including M. D. Anderson’s Specialized Program of Research Excellence in Ovarian Cancer; the Ovarian Cancer Research Fund, Inc.; and the Zarrow Foundation.”

Quoted Source: [“Researchers Identify and Shut Down Protein that Fuels Ovarian Cancer, M. D. Anderson-led team pinpoints blood vessel promoter’s role and targets it with siRNA,” M.D Anderson News Release, dated February 26, 2008]. See also “Effect of Interleukin-8 Gene Silencing With Liposome-Encapsulated Small Interfering RNA on Ovarian Cancer Cell Growth;” Merritt,W.M., Lin,Y.G., Spannuth,W.A., Fletcher,M.S., Kamat,A.A., Han,L.Y., Landen,C.N., Jennings,M., Geest,K., Langley,R.R., Villares,G., Sanguino,A., Lutgendorf,S.K., Lopez-Berestein,G., Bar-Eli,M.M., Sood, A.K.; Journal of the National Cancer Institute 2008 100(5):359-372.

Use of Liposomal siRNA to Target Ovarian Cancer Protein Known as “Focal-Adhesion Kinase (FAK)”

Recent work reported in October 2006 by Dr. Anil Sood at M.D. Anderson involved the use of a targeted “siRNAliposome in mice to identify and correct defective ovarian cancer cells. M. D. Anderson researchers used siRNA (which acts as a genetic “on/off” switch) to target an ovarian cancer protein known as focal-adhesion kinase (FAK), which is present in all ovarian cancer cells. FAK helps ovarian cancer cells survive and spread. The siRNA was rolled into a liposome – a ball of fat so small that its dimensions are measured in nanometers (billionths of a meter). Because of their tiny size, these liposomes have no problem traveling through the blood supply into cells that make up tumors through the so-called “Trojan Horse” effect. To test how well it worked, mice that were implanted with human ovarian tumors were given injections of the therapy for three to five weeks. The mice ovarian tumors experienced a 44% to 72% reduction in weight. Adding chemotherapy to the treatment boosted tumor weight reduction to the 94% to 98% range. The next step for the FAK siRNA liposome is testing for toxicity prior to studies in human patients.

Source: [ “Novel Therapy Shrinks Ovarian Tumors in Mice, Genetic Fragments Turn Off Cancer Growth Switch,” Cancer Newsline, October 2006, M.D. Anderson Cancer Center, University of Texas.]

Use of Liposomal siRNA to Target the Ovarian Cancer Kinase Known as “EphA2”

In an earlier in vitro studies, Anil Sood, M.D. et. al. demonstrated that when EphA2-targeting siRNA was combined with paclitaxel [Taxol®], tumor growth was dramatically reduced compared with treatment with paclitaxel and a nonsilencing siRNA. These studies show the feasibility of siRNA as a clinically applicable therapeutic modality.

Source: [“Therapeutic EphA2 Gene Targeting In vivo Using Neutral Liposomal Small Interfering RNA Delivery;” Landen,C.N., Chavez-Reyes, A., Bucana, C., Schmandt, R., T. Deavers, M., Lopez-Berestein, G. and Sood, A.K., The University of Texas M.D. Anderson Cancer Center, Houston, Texas; Cancer Research 65, 6910-6918, August 1, 2005.

Comment: The ultimate use of siRNA to treat ovarian cancer in humans holds future promise. Ovarian cancer survivors should monitor the development of this liposomal siRNA form of treatment because its use in human clinical trials could occur in the near future, assuming that pre-clinical trial toxicity tests demonstrate safety. Anil Sood, M.D. has developed the liposomal siRNA for IL-8, FAK, and EphA2. It is reported that human clinical trials with respect to the EphA2 siRNA treatment will begin within 12 months.