Salmonella

[Rich66]

J Mol Med. 2010 Aug;88(8):763-73. Epub 2010 Jun 5.
Salmonella-allies in the fight against cancer.

Leschner S, Weiss S.
Molecular Immunology, Helmholtz Centre for Infection Research, Inhoffenstr. 7, 38124, Braunschweig, Germany. sara.leschner@helmholtz-hzi.de


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Abstract

Cancer has become the second ranking cause of death in the industrialized world. Conventional anti-cancer therapies such as surgery, radiotherapy, and chemotherapy are effective in the treatment of solid tumors only to some extent. Furthermore, they are often associated with severe side effects. Use of bacteria as alternative cancer therapeutics has sporadically been followed over more than a century. The potential to target and colonize solid tumors could be shown for many different bacteria in the meantime. Such bacteria are either obligate anaerobic bacteria like Clostridium or Bifidobacterium or facultative anaerobic like Escherichia coli or Salmonella. Here we describe bacterial strains that were successfully applied mostly in animals bearing model tumors, although first clinical trials have been reported as well. Our review mainly concentrates on Salmonella enterica serovar Typhimurium (S. Typhimurium) since these bacteria were studied most intensively thus far. Importantly, S. Typhimurium were shown not only to colonize large established tumors but also exhibit the property to invade and affect metastases. We report on a potential mechanism by which such bacteria can invade solid tumors. Furthermore, we describe several successful attempts in which the bacteria have been used as carriers for recombinant therapeutic molecules that render bacteria more powerful in eradication of the established tumor. Such attempts should be considered starting points on the way to an effective and safe tumor therapy with the help of bacteria.

PMID: 20526574 [PubMed - in process]




J Cell Biochem. 2009 Apr 15;106(6):992-8.
Cancer metastasis directly eradicated by targeted therapy with a modified Salmonella typhimurium.

Hayashi K, Zhao M, Yamauchi K, Yamamoto N, Tsuchiya H, Tomita K, Hoffman RM.
AntiCancer, Inc., 7917 Ostrow Street, San Diego, CA 92111, USA.
Cancer metastasis is the life-threatening aspect of cancer and is usually resistant to standard treatment. We report here a targeted therapy strategy for cancer metastasis using a genetically-modified strain of Salmonella typhimurium. The genetically-modified strain of S. typhimurium is auxotrophic for the amino acids arginine and leucine. These mutations preclude growth in normal tissue but do not reduce bacterial virulence in cancer cells. The tumor-targeting strain of S. typhimurium, termed A1-R, and expressing green fluorescent protein (GFP), was administered to both axillary lymph and popliteal lymph node metastasis of human pancreatic cancer and fibrosarcoma, respectively, as well as lung metastasis of the fibrosarcoma in nude mice. The bacteria were delivered via a lymphatic channel to target the lymph node metastases and systemically via the tail vein to target the lung metastasis. The cancer cells expressed red fluorescent protein (RFP) in the cytoplasm and GFP in the nucleus linked to histone H2B, enabling color-coded real-time imaging of the bacteria targeting the metastatic tumors. After 7-21 days of treatment, the metastases were eradicated without the need of chemotherapy or any other treatment. No adverse effects were observed. This new strategy demonstrates the clinical potential of targeting and curing cancer metastasis with engineered bacteria without the need of toxic chemotherapy. Copyright 2009 Wiley-Liss, Inc.

PMID: 19199339 [PubMed - indexed for MEDLINE]





Amino Acids. 2009 Sep;37(3):509-21. Epub 2009 Mar 17.
Tumor-targeting amino acid auxotrophic Salmonella typhimurium.

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Hoffman RM.
AntiCancer Inc., San Diego, CA 92111, USA. all@anticancer.com
We have developed an effective bacterial cancer therapy strategy by targeting viable tumor tissue using Salmonella typhimurium auxotrophs that we have generated which grow in viable as well as necrotic areas of tumors. However, the auxotrophy severely restricts growth of these bacteria in normal tissue. The S. typhimurium A1-R mutant, which is auxotrophic for leu-arg and has high anti-tumor virulence, was developed in our laboratory. In vitro, A1-R infects tumor cells and causes nuclear destruction. A1-R was initially used to treat metastatic human prostate and breast tumors that had been orthotopically implanted in nude mice. Forty percent of treated mice were cured completely and survived as long as non-tumor-bearing mice. A1-R administered i.v. to nude mice with primary osteosarcoma and lung metastasis was highly effective, especially against metastasis. A1-R was also targeted to both axillary lymph and popliteal lymph node metastasis of human pancreatic cancer and fibrosarcoma, respectively, as well as lung metastasis of the fibrosarcoma in nude mice. The bacteria were delivered via a lymphatic channel to target the lymph node metastases and systemically via the tail vein to target the lung metastasis. The metastases were cured without the need of chemotherapy or any other treatment. A1-R was administered intratumorally to nude mice with an orthotopically transplanted human pancreatic tumor. The primary pancreatic cancer regressed without additional chemotherapy or any other treatment. A1-R was also effective against pancreatic cancer liver metastasis when administered intrasplenically to nude mice. The approach described here, where bacterial monotherapy effectively treats primary and metastatic tumors, is a significant improvement over previous bacterial tumor-therapy strategies that require combination with toxic chemotherapy. Three promoter clones engineered in S. enterica typhimurium were identified to have enhanced expression in bacteria growing in tumors relative to those growing in the spleen. The expression of therapeutics in Salmonella under the regulation of one or more promoters that are activated preferentially in tumors has the potential to improve the efficacy of Salmonella tumor therapy. Exploitation of the tumor-killing capability of Salmonella has great promise for a new paradigm of cancer therapy.

PMID: 19291366 [PubMed - indexed for MEDLINE]


Proc Natl Acad Sci U S A. 2007 Jun 12;104(24):10170-4. Epub 2007 Jun 4.
Monotherapy with a tumor-targeting mutant of Salmonella typhimurium cures orthotopic metastatic mouse models of human prostate cancer.

Zhao M, Geller J, Ma H, Yang M, Penman S, Hoffman RM.
AntiCancer Inc., 7917 Ostrow Street, San Diego, CA 92111, USA.


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Abstract

Bacterial infection occasionally has a marked therapeutic effect on malignancies, as noted as early as the 19th century. Recently, there have been attempts to develop cancer treatment by using tumor-targeting bacteria. These treatments were developed to deliver therapeutic molecules specifically to tumors. Researchers used anaerobic microorganisms that preferentially grew in necrotic tumor areas. However, the resulting tumor killing was, at best, limited. We have developed a far more effective bacterial cancer therapy by targeting viable tumor tissue by using Salmonella typhimurium leu-arg auxotrophs. Although these bacteria grow in viable as well as necrotic areas of tumors, the nutritional auxo trophy severely restricts growth in normal tissue. In the current study, we measured the antitumor efficacy of the S. typhimurium A1-R mutant, which is auxotrophic for leu-arg and has increased antitumor virulence selected by tumor passage. A1-R was used to treat metastatic PC-3 human prostate tumors that had been orthotopically implanted in nude mice. GFP was used to image tumor and metastatic growth. Of the 10 mice with the PC-3 tumors that were injected weekly with S. typhimurium A1-R, 7 were alive and well at the time the last untreated mouse died. Four A1-R-treated mice remain alive and well 6 months after implantation. Ten additional nontumor-bearing mice were injected weekly to determine the toxicity of S. typhimurium A1-R. No toxic effects were observed. The approach described here, where bacterial monotherapy effectively treats metastatic prostate tumors, is a significant improvement over previous bacterial tumor-therapy strategies that require combination with toxic chemotherapy.


BMC Cancer. 2010 Apr 17;10:146.
Role of nitric oxide in Salmonella typhimurium-mediated cancer cell killing.

Barak Y, Schreiber F, Thorne SH, Contag CH, Debeer D, Matin A.
Department of Microbiology and Immunology, Sherman Fairchild Science Building, Stanford University School of Medicine, 299 Campus Drive, Stanford, CA 94305, USA.


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Abstract

BACKGROUND: Bacterial targeting of tumours is an important anti-cancer strategy. We previously showed that strain SL7838 of Salmonella typhimurium targets and kills cancer cells. Whether NO generation by the bacteria has a role in SL7838 lethality to cancer cells is explored. This bacterium has the mechanism for generating NO, but also for decomposing it.
METHODS: Mechanism underlying Salmonella typhimurium tumour therapy was investigated through in vitro and in vivo studies. NO measurements were conducted either by chemical assays (in vitro) or using Biosensors (in vivo). Cancer cells cytotoxic assay were done by using MTS. Bacterial cell survival and tumour burden were determined using molecular imaging techniques.
RESULTS: SL7838 generated nitric oxide (NO) in anaerobic cell suspensions, inside infected cancer cells in vitro and in implanted 4T1 tumours in live mice, the last, as measured using microsensors. Thus, under these conditions, the NO generating pathway is more active than the decomposition pathway. The latter was eliminated, in strain SL7842, by the deletion of hmp- and norV genes, making SL7842 more proficient at generating NO than SL7838. SL7842 killed cancer cells more effectively than SL7838 in vitro, and this was dependent on nitrate availability. This strain was also ca. 100% more effective in treating implanted 4T1 mouse tumours than SL7838.
CONCLUSIONS: NO generation capability is important in the killing of cancer cells by Salmonella strains.

PMID: 20398414 [PubMed - indexed for MEDLINE]PMCID: PMC2868810Free PMC Article






J Photochem Photobiol A Chem. 2009 Jan 1;201(1):50-56.
Light-Induced Toxic Effects of Tamoxifen: A Chemotherapeutic and Chemopreventive Agent.

Wang L, Wang S, Yin JJ, Fu PP, Yu H.
Department of Chemistry, Jackson State University, Jackson, MS 39217.


FREE TEXT

Abstract

Tamoxifen is a powerful drug used to treat breast cancer patients, and more than 500,000 women in the U. S. are being treated with this drug. In our study, tamoxifen is found to be photomutagenic in Salmonella typhimurium TA102 at concentrations as low as 0.08 muM and reaches maximum photomutagenicity at 0.4 muM under a light dose equivalent to 20 min sunlight. These concentrations are comparable to the plasma tamoxifen concentration of 0.4 to 3 muM for patients undergoing tamoxifen therapy. The toxicity seems to be the result of DNA damage and/or lipid peroxidation caused by light irradiation of tamoxifen. The DNA damage caused by irradiation of PhiX174 DNA in the presence of tamoxifen appears to be formation of DNA-tamoxifen covalent adducts, not single strand/double strand cleavages, and there is no oxygen involvement. This is confirmed by EPR experiments that carbon-centerd radicals are formed by light irradiation of tamoxifen and there is no singlet oxygen formation. Although superoxide radical is formed, it is not involved in DNA damage.

PMID: 20046228 [PubMed]PMCID: PMC2637528Free PMC Article





Cancer Gene Therapy (2011) 18, 457–466; doi:10.1038/cgt.2011.10; published online 25 March 2011
In tumors Salmonella migrate away from vasculature toward the transition zone and induce apoptosis

S Ganai^1,2, R B Arenas^1,2,3, J P Sauer⁴, B Bentley³ and N S Forbes^2,3,4

1. ¹Department of Surgery, Baystate Medical Center, Tufts University School of Medicine, Springfield, MA, USA
2. ²Program in Molecular and Cellular Biology, University of Massachusetts Amherst, Amherst, MA, USA
3. ³Pioneer Valley Life Sciences Institute, Springfield, MA, USA
4. ⁴Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, MA, USA

Correspondence: Dr NS Forbes, Department of Chemical Engineering, University of Massachusetts Amherst, 101 Goessmann Laboratory, 686 North Pleasant Street, Amherst, MA 01003, USA. E-mail: forbes@ecs.umass.edu
Received 14 June 2010; Revised 4 October 2010; Accepted 26 December 2010; Published online 25 March 2011.

Top of pageAbstract

Motile bacteria can overcome diffusion resistances that substantially reduce the efficacy of standard cancer therapies. Many reports have also recently described the ability of Salmonella to deliver therapeutic molecules to tumors. Despite this potential, little is known about the spatiotemporal dynamics of bacterial accumulation in solid tumors. Ultimately this timing will affect how these microbes are used therapeutically. To determine how bacteria localize, we intravenously injected Salmonella typhimurium into BALB/c mice with 4T1 mammary carcinoma and measured the average bacterial content as a function of time. Immunohistochemistry was used to measure the extent of apoptosis, the average distance of bacteria from tumor vasculature and the location of bacteria in four different regions: the core, transition, body and edge. Bacteria accumulation was also measured in pulmonary and hepatic metastases. The doubling time of bacterial colonies in tumors was measured to be 16.8 h, and colonization was determined to delay tumor growth by 48 h. From 12 and 48 h after injection, the average distance between bacterial colonies and functional vasculature significantly increased from 130 to 310 μm. After 48 h, bacteria migrated away from the tumor edge toward the central core and induced apoptosis. After 96 h, bacteria began to marginate to the tumor transition zone. All observed metastases contained Salmonella and the extent of bacterial colocalization with metastatic tissue was 44% compared with 0.5% with normal liver parenchyma. These results demonstrate that Salmonella can penetrate tumor tissue and can selectively target metastases, two critical characteristics of a targeted cancer therapeutic.