Oncology

Bacteria participate in the genesis of a variety of at least over 20% of all cancer cases are attributable to infectious agents. Microorganisms can promote carcinogenesis by inducing inflammation, release of PAMPs, increasing cell proliferation, altering stem cell dynamics, and producing metabolites such as butyrate, which affect DNA integrity and immune regulation.

However, little is known about the contribution of the microbiome to the development of malignancies.The HMI has developed an original workflowthat enable the identification of novel, unculturable microbial species,associated with cancerswithin the human microbiota. This genomic-based workflow using combined genetic, culture and metagenomics methods lead to the discovery of more than 30 novel previously unknown microbial species associated with oncogenesisof different localization.

Ongoing studies are dedicated to obtain a clear picture of the cancer associations with these novel bacterial pathogens that can be a life-saving event for individuals harboring these microorganisms.

Translation potential is realized by

  • Early detection of  cancer by detecting HMI discovered, previously unknown bacteria
  • Use of cancerogenic bacteria as therapeutic and preventive targets

The scope of our microbiota-related cancer research includes the following cancer types:


Selected publications:

Onuma, Amblessed, Jiayi He, Yujia Xia, Hongji Zhang, Dmitry Genkin, George Tetz, Hai Huang, and Allan Tsung. Neutrophil extracellular traps blockade in combination with PD-1 inhibition in treatment of colorectal cancer metastasis. (2020): e16002-e16002

 

Journal of Clinical Oncology (2020)

Neutrophil extracellular traps blockade in combination with PD-1 inhibition in treatment of colorectal cancer metastasis

Publication Type Journal Article
 Authors Amblessed Onuma

Jiayi He

Yujia Xia

Hongji Zhang

Dmitry Genkin

George Tetz

 Abstract Background: Immune checkpoint inhibitors (ICIs) are currently approved for microsatellite instability-high metastatic colorectal cancer (mCRC) however reported objective response rate to monotherapy range between 28-52%. Neutrophil Extracellular Traps (NETs), an extracellular network of DNA and proteins expelled by neutrophils into the tumor microenvironment, promote CRC metastasis by inducing potent immunosuppressive effects. We hypothesize that targeting this network may improve response rates to immune checkpoint therapy. The purpose of our study is to investigate the effect of combination DNase I treatment, a NET depleting agent, and PD-1 blockade in mCRC progression.

Methods: Subcutaneous MC38 (MSI-H adenocarcinoma of the colon) tumors were established in 6-week-old mice. Treatment was initiated six days after tumor inoculation with daily intraperitoneal (i.p) injections of DNase I followed by i.p anti-PD-1 treatment administered every 3 days. Animals were divided into treatment groups: control, DNase alone, anti-PD-1 alone and combination of DNase I with anti-PD-1 (n = 6 mice/ group).

Results: Tumors were successfully established after 6 days of inoculation. These tumors expressed high neutrophil infiltration and NETs. To determine the effects of combination therapy on tumor progression, we measured tumor volume and time to progression (TTP). We found that mice treated with combination DNase I and anti-PD-1 had significantly lower mean tumor volume compared to anti-PD-1 alone (1372.68mm3 vs 2193.20 mm3, p-value = 0.043). TTP was higher in the combination group compared to anti-PD-1 treatment alone (median time to progression 22 vs 17 days, p-value = 0.004). Next we sought to determine the mechanism behind this effect by investigating if NETs blockade modulated the tumor microenvironment. We found that treatment with DNase I decreased exhaustion of CD8+ T-cells in the tumor compared to no treatment.

Conclusions: Targeting NETs in combination with immune checkpoint inhibition may be an option to improve response rate to immune checkpoint inhibitors through decreasing exhausted CD8+ T-cells.

Year of
Publication
2020
 Journal Journal of Clinical Oncology
 DOI 10.1200/JCO.2020.38.15_suppl.e16002
Xia, Y., He, J., Zhang, H., Wang, H., Tetz, G., Maguire, C.A., Wang, Y., Onuma, A., Genkin, D., Tetz, V. and Stepanov, A., 2020. AAV‐mediated gene transfer of DNase I in the liver of mice with colorectal cancer reduces liver metastasis and restores local innate and adaptive immune response. Molecular Oncology, 14(11), pp.2920-2935.

Molecular Oncology (2020)

AAV‐mediated gene transfer of DNase I in the liver of mice with colorectal cancer reduces liver metastasis and restores local innate and adaptive immune response

Publication Type Journal Article
 Authors Yujia Xia,  Jiayi He,  Hongji Zhang, Han Wang, George Tetz, Casey A. Maguire,  Yu Wang,  Amblessed Onuma,  Dmitry Genkin, Victor Tetz, Alexey Stepanov,  Stanislav Terekhov,  Valeria Ukrainskaya,  Hai Huang, and Allan Tsung
 Abstract Liver metastasis is the main cause of colorectal cancer (CRC)‐related death. Neutrophil extracellular traps (NETs) play important roles in CRC progression. Deoxyribonuclease I (DNase I) has been shown to alter NET function by cleaving DNA strands comprising the NET backbone. Moreover, DNase I displays high antimetastatic activity in multiple tumor models. To circumvent long‐term daily administrations of recombinant DNase I, we have developed an adeno‐associated virus (AAV) gene therapy vector to specifically express DNase I in the liver. In this study, we demonstrate AAV‐mediated DNase I liver gene transfer following a single intravenous injection suppresses the development of liver metastases in a mouse model of CRC liver metastasis. Increased levels of neutrophils and NET formation in tumors are associated with poor prognosis in many patients with advanced cancers. Neutrophil infiltration and NET formation were inhibited in tumor tissues with AAV‐DNase I treatment. This approach restored local immune responses at the tumor site by increasing the percentage of CD8+ T cells while keeping CD4+ T cells similar between AAV‐DNase I and AAV‐null treatments. Our data suggest that AAV‐mediated DNase I liver gene transfer is a safe and effective modality to inhibit metastasis and represents a novel therapeutic strategy for CRC.
Year of
Publication
2020
 Journal Molecular Oncology
 DOI :10.1128/genomeA.01432-16
Tetz, G., Vecherkovskaya, M., Zappile, P., Dolgalev, I., Tsirigos, A., Heguy, A., & Tetz, V. (2017). Complete Genome Sequence of Kluyvera intestini sp. nov., Isolated from the Stomach of a Patient with Gastric Cancer. Genome Announcements, 5(43), e01184-17.

Genome announcements (2016)

Draft Genome Sequence of Kluyvera intestini Strain GT-16 Isolated from the Stomach of a Patient with Gastric Cancer

Publication Type Journal Article
 Authors George TetzVictor Tetz
 Abstract Here, we report the complete genome sequence of the novel, non-spore-forming Kluyvera intestini strain GT-16, isolated from the stomach of a patient with gastric cancer. The genome is 5,868,299 bp in length with a GC content of 53.0%. It possesses 5,350 predicted protein-coding genes encoding virulence factors and antibiotic resistance proteins.
Year of
Publication
 2016
 Journal Genome announcements
 DOI :10.1128/genomeA.01432-16
Tetz, G., & Tetz, V. (2017). Introducing the sporobiota and sporobiome. Gut Pathogens, 9:38 DOI 10.1186/s13099-017-0187-8

Gut Pathogens (2017)

Introducing the Sporobiota and Sporobiome

Publication Type Jornal article
 Authors George TetzVictor Tetz
 Abstract Unrelated spore-forming bacteria share unique characteristics stemming from the presence of highly resistant endospores, leading to similar challenges in health and disease. These characteristics are related to the presence of these highly transmissible spores, which are commonly spread within the environment and are implicated in host-to-host transmission. In humans, spore-forming bacteria contribute to a variety of pathological processes that share similar characteristics, including persistence, chronicity, relapses and the maintenance of the resistome. We first outline the necessity of characterizing the totality of the spore-forming bacteria as the sporobiota based on their unique common characteristics. We further propose that the collection of all genes of spore-forming bacteria be known as the sporobiome. Such differentiation is critical for exploring the cross-talk between the sporobiota and other members of the gut microbiota, and will allow for a better understanding of the implications of the sporobiota and sporobiome in a variety of pathologies and the spread of antibiotic resistance.
Year of
Publication
 2017
 Journal Gut Pathogens
 DOI 10.1186/s13099-017-0187-8.
Tetz, V., & Tetz, G. (2017). Draft Genome Sequence of a Strain of Bacillus intestinalis sp. nov., a New Member of Sporobiota Isolated from the Small Intestine of a Single Patient with Intestinal Cancer. Genome Announcements, 5(22), e00489-17.
Publication Type
Authors
Abstract
Year of
Publication
Journal
DOI
Tetz, G., & Tetz, V. (2016). Complete Genome Sequence of a Novel Bacillus sp. VT 712 Strain Isolated from the Duodenum of a Patient with Intestinal Cancer. Genome Announcements, 4(4), e00786-16.

Genome announcements (2016)

Complete Genome Sequence of a Novel Bacillus sp. VT 712 Strain Isolated from the Duodenum of a Patient with Intestinal Cancer

Publication Type Journal Article
 Authors George TetzVictor Tetz
 Abstract We report here the complete genome sequence of the spore-forming Bacillus sp. strain VT 712 isolated from the duodenum of a patient with intestinal cancer. The genome is 3,921,583 bp, with 37.9% G+C content. It contains 3,768 predicted protein-coding genes for multidrug resistance transporters, virulence factors, and daunorubicin resistance.
Year of
Publication
 2016
 Journal Genome announcements
 DOI 10.1128/genomeA.00786-16
Tetz, G., Tetz, V., & Vecherkovskaya, M. (2016). Genomic characterization and assessment of the virulence and antibiotic resistance of the novel species Paenibacillus sp. strain VT-400, a potentially pathogenic bacterium in the oral cavity of patients with hematological malignancies. Gut Pathogens, 8(1), 1.

Genomic characterization and assessment of the virulence and antibiotic resistance of the novel species Paenibacillus sp. strain VT-400, a potentially  pathogenic bacterium in the oral cavity of patients with hematological  malignancies

Gut pathogens (2016)

Publication Type Journal Article
Authors George Tetz
Victor Tetz
Maria Vecherkovskaya
Abstract BackgroundPaenibacillus sp. strain VT-400, a novel spore-forming bacterium, was isolated from patients with hematological malignancies.

Methods

Paenibacillus sp. strain VT-400 was isolated from the saliva of four children with acute lymphoblastic leukemia. The genome was annotated using RAST and the NCBI Prokaryotic Genome Annotation Pipeline to characterize features of antibiotic resistance and virulence factors. Susceptibility to antibiotics was determined by the Kirby–Bauer disc diffusion method. We used a mouse model of pneumonia to study virulence in vivo. Mice were challenged with 7.5 log10–9.5 log10 CFU, and survival was monitored over 7 days. Bacterial load was measured in the lungs and spleen of surviving mice 48 h post-infection to reveal bacterial invasion and dissemination.

Results

Whole-genome sequencing revealed a large number of virulence factors such as hemolysin D and CD4+ T cell-stimulating antigen. Furthermore, the strain harbors numerous antibiotic resistance genes, including small multidrug resistance proteins, which have never been previously found in the Paenibacillus genus. We then compared the presence of antibiotic resistance genes against results from antibiotic susceptibility testing. Paenibacillus sp. strain VT-400 was found to be resistant to macrolides such as erythromycin and azithromycin, as well as to chloramphenicol and trimethoprim–sulphamethoxazole. Finally, the isolate caused mortality in mice infected with ≥8.5 log10 CFU.

Conclusions

Based on our results and on the available literature, there is yet no strong evidence that shows Paenibacillus species as an opportunistic pathogen in immunocompromised patients. However, the presence of spore-forming bacteria with virulence and antibiotic resistance genes in such patients warrants special attention because infections caused by spore-forming bacteria are poorly treatable.

Year of
Publication
2016
Journal Gut Pathogens
DOI 10.1186/s13099-016-0089-1
Tetz, G., & Tetz, V. (2015). Draft Genome Sequence of Acinetobacter sp. Strain VT-511 Isolated from the Stomach of a Patient with Gastric Cancer. Genome Announcements, 3(5), e01202-15.

Genome announcements (2015)

Publication Type Journal Article
Authors George Tetz
Victor Tetz
Abstract We report the draft genome sequence of Acinetobacter sp. strain VT-511, which was
obtained from the stomach of a patient with gastric cancer. The genome of Acinetobacter sp. VT-511 is composed of approximately 3,416,321 bp and includes
3,214 predicted protein-coding genes.
Year of Publication 2015
Journal Genome announcements
DOI 10.1128/genomeA.01202-15
Tetz G, Tetz V, Vecherkovskaya. (2015) Complete Genome Sequence of Paenibacillus sp. Strain VT 400, Isolated from the Saliva of a Child with Acute Lymphoblastic Leukemia. Genome Announcements; 3(4), e00894-15. doi:10.1128/genomeA.00894-15

Genome announcements (2015)

Publication Type Journal Article
Authors George Tetz
Victor Tetz
Maria Vecherkovskaya
Abstract We report here the complete genome sequence of spore-forming Paenibacillus sp. strain VT 400, isolated from the saliva of a child with acute lymphoblastic leukemia. The genome consists of 6,986,122 bp, with a G+C content of 45.8%. It possesses 5,777 predicted protein-coding genes encoding multidrug resistance transporters, virulence factors, and resistance to chemotherapeutic drugs.
Year of Publication 2015
Journal Genome announcements
DOI 10.1128/genomeA.00894-15
Strain VT-13-104 Isolated from the Intestine of a Patient with Duodenal Cancer. Genome Announcements; 3(4), e00705-15.

Genome announcements (2015)

Publication Type Journal Article
Authors George Tetz
Victor Tetz
Abstract We report the complete genome sequence of Bacilli bacterium strain VT-13- 104 isolated from the intestine of a patient with duodenal cancer. The genome is composed of 3,573,421 bp, with a G+C content of 35.7%. It possesses 3,254 predicted protein-coding genes encoding multidrug resistance transporters, resistance to antibiotics, and virulence factors.
Year of Publication 2015
Journal Genome announcements
DOI 10.1128/genomeA.00705-15