OU-MRU Vol.7 Feb 2015

Okayama University Medical Research Updates （OU-MRU）

2015.02 Vol.7

Source: Okayama University (Japan), Center for Public Affairs and Communications
For immediate release: 25 February 2015
Okayama University research: Anticancer virus solution provides an alternative to surgery(Okayama, 25 February) Researchers at Okayama demonstrate that injection of a virus
solution followed by tumour removal can eradicate cancer metastasis in lymph nodes
without the need for preventative surgery.

While early-stage gastrointestinal cancers can be treated non-surgically, once the cancer has
invaded to a particular depth preventative – ‘prophylactic’ – surgery is routine. The
frequency of lymph node metastasis increases significantly once the cancer has penetrated
the submucosal layers, and as there is no way of determining whether the cancer has
metastasized in the lymph nodes they will be surgically removed just in case. Now
researchers at Okayama University and the University of California in San Diego havedemonstrated that injection of a viral solution can eradicate lymph node metastasis making
prophylactic surgery unnecessary.

To treat early stage cancers a saline solution is injected creating a fluid cushion, which raises
and isolates the tumour. The tumour is then readily removed by equipment through astandard endoscopic viewing tube inserted in the gastrointestinal tract. However if thecancer has already penetrated the submucosal layer it will be prone to relapse in thelymphatic system.

Toshiyoshi Fujiwara and his colleagues adapted the standard endoscopic treatment byinjecting a solution of Telomelysin - a virus known to kill epithelial and mesenchymal
malignant cells - instead of saline solution. They tested the treatment in a mouse model,
injecting green-fluorescent-protein-labelled cancer cells into the submucosal layers of therectum, which developed lymph node metastasis. Fluorescence imaging showed that cancer
cells were successfully eliminated by the treatment with virus solution, in contrast to micetreated with saline solution instead. In addition, treated mice showed no relapse four weeks
after the treatment

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1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 Japan© OKAYAMA University

OU-MRU Vol.7 Feb 2015

In their report of the results the researchers conclude, “From a clinical view point, this new,simple, and robust strategy is a more realistic and promising bench-to-bedside translation
than prophylactic surgery for ablation of potential lymph node metastases in earlygastrointestinal cancer patients.”

Background
Submucosal layer cancer invasion
Early stage gastrointestinal cancers are defined by the level of the cancer invasion reaching
no further than the submucosa. Endoscopic treatment removes these tumours by dissecting
the submucosal layers.

For esophageal gastric and colorectal submucosally invaded cancers the frequency at whichthe cancer is found to metastasize in the lymph nodes is approximately 10 to 20%. The
lymphatic system distributes fluids, proteins, chemicals, cells and drugs. This makes it amajor pathway for the spread of metastatic cancers so that cancerous invasion of thelymphatic system is particularly problematic.

It is very difficult to determine whether the cancer has metastases in the lymph nodes. As aresult lymph node surgery just in case is routine when treating esophageal gastric andcolorectal submucosal cancers, even though in many cases it may not have been necessary.

Anticancer viruses
Previous research has demonstrated that certain viruses replicate in cancer cells and breakthem down, and may be developed for cancer treatments. The researchers further exploitedthe role of the lymph system in mediating proteins and fluids, a function which makes it
more prone to exposure to a virus injected in the surrounding area.

The researchers experimented with Telomelysin – a telomerase-dependent,
tumor-killing replicating adenoviral agent (OBP-301). The virus is known to kill epithelial andmesenchymal malignant cells.

OKAYAMA University1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 Japan© OKAYAMA University

OU-MRU Vol.7 Feb 2015

Exploiting lymphatic functions with the virus
The researchers first tested the virus on green-fluorescent-protein-labelled colorectal
cancer cell lines with. Using fluorescence imaging they observed rapid cell death in response
to injection with the virus while there was no such response in cell lines treated with mutant
strains of the virus that had replication deficiencies.

The researchers demonstrated how their treatment exploited the lymph node function
using mouse models injected with red-fluorescent-protein-labelled lymph nodemetastasized cancer cells. After six days the virus labelled with green fluorescent protein
was injected and fluorescence images showed the position of the virus coincided with themetastatic foci in the lymph nodes.

Reference
Kikuchi S, Kishimoto H, Tazawa H, Hashimoto Y, Kuroda S, Nishizaki M, Nagasaka T,
Shirakawa Y, Kagawa S, Urata Y, Hoffman RM, Fujiwara T: Biological Ablation of Sentinel
Lymph Node Metastasis in Submucosally Invaded Early Gastrointestinal Cancer. Mol Ther.
2014 Dec 19.
DOI: 10.1038/mt.2014.244.

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1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 Japan© OKAYAMA University

OU-MRU Vol.7 Feb 2015

Figure caption
Cytopathic effect of the virus (OBP-301) on human colorectal cancer cell lines. (a) Greenfluorescent-protein (GFP)-labelled colorectal cancer cells were infected with replicationdeficient adenovirus (dl312) or the treatment virus (OBP-301) at a multiplicity of injection(MOI) of 10. Cell morphology and GFP expression were evaluated at the indicated time
points by phase-contrast (top panels) and fluorescence (bottom panels) microscopy,
respectively. Magnification: ×200. Scale bar, 200 μm.

Correspondence toProfessor Toshiyoshi Fujiwara, M.D., Ph.D.
Department of Gastroenterological Surgery, Okayama
University Graduate School of Medicine, Dentistry andPharmaceutical Sciences, 2-5-1 Shikata-cho, Kita-ku,Okayama 700-8558, JapanEMAIL: toshi_f@md.okayama-u.ac.jp

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1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 Japan© OKAYAMA University

OU-MRU Vol.7 Feb 2015

Further information
Okayama University
1-1-1 Tsushima-naka , Kita-ku , Okayama 700-8530, Japan
Planning and Public Information Division, Okayama University
E-mail: www-adm@adm.okayama-u.ac.jp
Website: http://www.okayama-u.ac.jp/index_e.html
Okayama Univ. e-Bulletin：http://www.okayama-u.ac.jp/user/kouhou/ebulletin/
Okayama University Medical Research Updates （OU-MRU）
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from blood samples for genetic testing
Vol.2：Ensuring a cool recovery from cardiac arrest
Vol.3：Organ regeneration research leaps forward
Vol.4：Cardiac mechanosensitive integrator
Vol.5：Cell injections get to the heart of congenital defects
Vol.6：Fourth key molecule identified in bone development

About Okayama UniversityOkayama University is one of the largest
comprehensive universities in Japan withroots going back to the Medical Training
Place sponsored by the Lord of Okayama
and established in 1870. Now with 1,300
faculty and 14,000 students, the University
offers courses in specialties ranging frommedicine and pharmacy to humanities
and physical sciences. Okayama
University is located in the heart of Japan
approximately 3 hours west of Tokyo byShinkansen.

OKAYAMA University
1-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530 Japan© OKAYAMA University