Regulatory T (Treg) cells play a central role in immune tolerance and prevention of aberrant immune responses. Several studies have suggested that the risk of GVHD after allogeneic hematopoietic cell transplantation (HCT) can be ameliorated by increasing Tregs. We have developed an approach of in vivo expansion of Tregs with RGI-2001, a novel liposomal formulation of a synthetic derivative of alpha-galactosylceramide, a naturally occurring ligand that binds to CD1 and activates and expands invariant natural killer cells. In preclinical studies, a single intravenous infusion of RGI-2001 expanded Treg and could ameliorate GVHD in a mouse model of allogeneic HCT. To explore the role of RGI-2001 in clinical HCT, we initiated a Phase IIa clinical trial (n=29), testing two different doses of RGI-2001 administered as a single infusion on day 0 of allogeneic HCT. RGI-2001 was well tolerated and without infusion reactions or cytokine release syndrome. A subset of patients (8/29, 28%) responded to RGI-2001 by inducing a markedly increased number of cells with a Treg phenotype. The Treg had a high Ki-67 index and were almost exclusively Helios+ and Foxp3+, indicating that their accumulation was due to expansion of natural Treg. Notably, the incidence of grade 2–4 GVHD in the eight patients who responded to RGI-2001 was 12.5%, compared to 52.4% in the 21 patients who did not respond. No grade 3–4 GVHD was observed in the responder group, compared to a 9.5% incidence among nonresponders. Immunosuppression with sirolimus was also associated with a low incidence of GVHD, suggesting that RGI-2001 may have synergized with sirolimus to promote Treg expansion.

Evidence of cancer immunosurveillance and immunoediting processes has been primarily demonstrated in mouse models of chemically induced oncogenesis. Although these models are very tractable, they are characterized by high mutational loads that represent a minority of human cancers. In this study, we sought to determine whether cancer immunosurveillance and immunoediting could be demonstrated in a more clinically relevant oncogene-induced model of carcinogenesis, the MMTV-PyMT (PyMT) mammary carcinoma model. This model system in the FVB/NJ strain background was previously used to demonstrate that adaptive immunity had no role in limiting primary cancer formation and in fact promoted metastasis, thus calling into question whether cancer immunosurveillance operated in preventing the development of breast cancer. Our current study in the C57BL/6 strain backgrounds provides a different conclusion, as we report here the existence of an adaptive immunosurveillance of PyMT mammary carcinomas using two independent models of immune deficiency. PyMT mice bred onto a Rag1 ¡/¡ background or immune suppressed by chronic tacrolimus therapy both demonstrated accelerated development of mammary carcinomas. By generating a bank of cell lines from these animals, we further show that a subset of PyMT cell lines had delayed growth after transplantation into wild-type (WT) syngeneic, but not immune-deficient hosts. This reduced growth rate in immunocompetent animals was characterized by an increase in immune cell infiltration and tissue differentiation. Furthermore, loss of the immune cell infiltration that characterized immunoediting of slow growing cell lines, changed them into fast growing variants capable of progressing in the immunocompetent model. In conclusion, our study provides evidence that immunosurveillance and immunoediting of PyMT-derived cell lines modulate tumor progression in this oncogene-induced model of cancer.

The cancer stem cell (CSC) paradigm posits that specific cells within a tumor, so-called CSC-like cells, have differing levels of tumorigenicity and chemoresistance. Original studies of CSCs identified them in human cancers and utilized mouse xenograft models to define the cancer initiating properties of these cells, thereby hampering the understanding of how immunity could affect CSCs. Indeed, few studies have characterized CSCs in the context of cancer immunoediting, and it is currently not clear how immunity could impact on the levels or stem-like behavior of CSCs. Using the well-studied 3 0 methylcholanthrene (MCA) model of primary sarcoma formation, we have defined a CSC-like population within MCA-induced sarcomas as expressing high levels of stem cell antigen-1 (Sca-1) and low levels of CD90. These Sca-1 C CD90 ¡ CSC-like cells had higher tumor initiating ability, could spontaneously give rise to Sca-1-negative cells, and formed more sarcospheres than corresponding non-CSC-like cells. Moreover, when examining MCA-induced sarcomas that were in the equilibrium phase of cancer growth, higher levels of CSC-like cells were found compared to MCA-induced sarcomas in the escape phase of cancer progression. Notably, CSC-like cells also emerged during escape from anti-PD-1 or anti-CTLA4 therapy, thus suggesting that CSC-like cells could evade immune therapy. Finally, we demonstrate that paradoxically, interferon (IFN)-g produced in vivo by immune cells could promote the emergence of CSClike cells. Our findings define the existence of a Sca1 C CD90 ¡ CSC-like population in the MCA-sarcoma model capable of differentiation, tumorsphere formation, and increased tumor initiation in vivo. These cells may also act as mediators of immune resistance during cancer immunoediting and immune therapy.

및 염증성 지표물질(요산, C-reactive protein: CRP, RF 및 homocystein) 농도를 분석 및 비교하였다. 연구결과 오디 추출물 투여에 따른 NMG와 AMG간 의 체성분에는 차이가 없었다. AMG의 CRP 수준은 0.80±0.05 mg/dL에서 0.55±0.02 mg/dL로 유의적으로 감소하였다 (p<0.05). AMG의 오디 추출물 투여 전의 혈청 TBARS 수준(63.04±12.20 mol/L)은 투여 후(57.44±11.16 mol)와 유의 적인 차이는 없었으나, 감소하는 경향을 보였다. AMG의 혈청 FRAP 수준은 급여 전(1239.02±63.22 mol)에 비해 급 여 후(1556.21±11.16 mol) 유의적으로 증가되었다(p<0.05). AMG의 혈청 TNF-α가 8.78±0.12pg/mL에서 6.58±0.16 pg/mL로, IL-2 수준은 5.41±0.71 pg/mL에서 3.94±0.03 pg/mL로, IL-4 수준은 7.21±0.61 pg/mL에서 5.15±0.36 pg/mL

The cancer stem cell (CSC) hypothesis stipulates that tumors follow a hierarchical organization where a subpopulation of cells endowed with stem cell characteristics initiates and maintains the malignant progression. Using the murine MCA sarcoma model system, a widely recognized model for studying cancer immunosurveillance and rejection mechanisms, we sought to explore how hierarchical tumor progression occurs during cancer immunosurveillance. The first step was to define CSC in the MCA sarcoma model. We identified an interesting heterogeneity of the tumor population based on Sca1 and CD90 expression. Purification of the Sca1+ and Sca1+/CD90+ in various cell lines and subsequent in vitro culture demonstrated that the Sca1+/CD90-population is able to regenerate the initial tumor heterogeneity. Transplantation of those two populations in RAGxγc-/- hosts demonstrated either a more rapid onset of sarcoma in mice injected with Sca1+ cells. Interestingly, phenotypic analysis of escaping tumors revealed an increase in Sca1+ cells. Finally, in vitro treatment with IFNg led to a substantial increase in Sca1 expression that correlated with an increase in cells' stemness properties as suggested by the elevated sphere forming capacity of IFNg treated cells. This data suggest that cancer stemness may be modulated by anti-cancer immune responses and may represent an additional mechanism of tumor immune escape.