(M1330-05-29) A Listeria-Based Vaccine Targeting Interferon-Stimulated Gene 15 for Renal Cell Carcinoma

Purpose: Interferon-stimulated gene 15 (ISG15) is the first identified ubiquitin-like modifier and has been implicated for its central role in innate immunity against intracellular pathogens. Interestingly, there is a growing body of evidence that demonstrated the role of ISG15 in cancer progression. Here, we investigate to understand if ISG15 could be a novel cancer-associated antigen in renal cell carcinomas (RCC). We aim to (i) identify the prognosis signature of ISG15 expression in RCC (ii) explore if ISG15 can be targeted by means of Listeria-based vaccines, and (iii) analyze how Listeria-based vaccines targeting ISG15 change the tumor microenvironment in syngeneic RCC mouse models.

Methods: Data on RNA and protein expression of ISG15 and the Kaplan–Meier survival analysis were obtained from Human Protein Atlas, The Cancer Genome Atlas, and from the University of Alabama at Birmingham, Comprehensive Cancer Center (UALCAN). All mouse experiments were performed in accordance with the regulations of the Institutional Animal Care and Use Committee (IACUC) at the TTUHSC. Listeria-based vaccines targeting ISG15, Lm-LLO-ISG15, and the control Listeria, Lm-LLO-OVA were constructed and cultured as previously described.

Results: ISG15 is highly expressed in RCC tumors compared to normal kidneys and is significantly associated with an unfavorable prognosis. The expression of ISG15 is increased with kidney cancer stages and tumor grades and does not discriminate between races and sexes. Consistent with human data, we found that Renca (a murine RCC cell line) also expressed a higher level of ISG15 compared to the normal fibroblast cell line (3T3-NIH). The expression of ISG15 is further enhanced by stimulation with type I interferon. In subcutaneous syngeneic RCC mouse models, vaccination Lm-LLO-ISG15 intraperitoneally significantly reduces tumor growth rate and final tumor mass compared to Lm-LLO-OVA. Lm-LLO-ISG15 inflames and modulates the immunologic profiles of the tumor microenvironment (TME) by (i) increasing the number of tumor-infiltrating functional CD8+ T cells (CD8+IFNγ+, CD8+IFN-γ+TNF-α+, CD8+CD62Llow), (ii) increasing the tumor-infiltrating monocytic subtype of myeloid-derived suppressor cells (m-MDSCs), and (iii) induces the expression of programmed cell death protein 1 (PD-1).

Conclusion: ISG15 is a novel cancer-associated antigen and a potential target for active immunotherapies including Lm-LLO-ISG15. Lm-LLO-ISG15 significantly controls tumor burden in the subcutaneous syngeneic RCC mouse models. Our initial findings suggest that Lm-LLO-ISG15 is efficacious against RCC and sensitizes the tumors with therapies that either target the PD-1 pathway or suppress m-MDSCs.

References: 1. Perng Y-C, Lenschow DJ: ISG15 in antiviral immunity and beyond. Nature Reviews Microbiology 2018, 16:423-439.
2. Chandrashekar DS, Bashel B, Balasubramanya SAH, Creighton CJ, Ponce-Rodriguez I, Chakravarthi B, Varambally S: UALCAN: A Portal for Facilitating Tumor Subgroup Gene Expression and Survival Analyses. Neoplasia 2017, 19:649-658.
3. Wood LM, Pan ZK, Seavey MM, Muthukumaran G, Paterson Y: The ubiquitin-like protein, ISG15, is a novel tumor-associated antigen for cancer immunotherapy. Cancer Immunol Immunother 2012, 61:689-700.


The expression of ISG15 in normal kidney tissues and primary RCC tumors in different subtypes, sexes, grades, tumor grades, and cancer stages along with its prognostic signature.


Intraperitoneal vaccination of Lm-LLO-ISG15 significantly reduces tumor growth rate and final tumor mass compared to controlled Listeria


Lm-LLO-ISG15 increases the influx of tumor-infiltrating functional CD8+ T cells and monocytic subtype of myeloid-derived suppressor cells (m-MDSCs), while inducing the expression of programmed cell death protein 1 (PD-1).