Accumulation of MDSC subsets in renal cell carcinoma correlates with grade and progression free survival, and is associated with intratumoral expression of IL-1β, IL-8 and CXCL5

Myeloid derived suppressor cells (MDSC, CD33+CD11b+ HLA-DR low/-) play a major role in tumor-mediated immune evasion and are composed of at least 3 subsets PMN (CD15+), monocytic (CD14+) and lineage-negative (CD15-CD14-), and each has been shown to be significantly increased in some human tumor types and to correlate with metastatic burden, clinical cancer stage and outcome. Less in known about the MDSC subsets that accumulate in tumors such as renal cell carcinoma (RCC) and the cytokines/chemokines involved in their recruitment. Flow cytometry analysis of peripheral blood mononuclear cells (PBMC, n = 20) and nephrectomy samples (n = 39, stage 1-4) showed increased levels of total MDSC in RCC patients compared to normal controls (n = 15), with PMN- and Lin- MDSC subsets dominating in the blood and tumor of RCC patients. Blood levels of total MDSC, PMN-MDSC and Lin-MDSC correlated with tumor grade (p = 0.026, p = 0.006 and p = 0.045, respectively), while blood levels of total MDSC and Lin-MDSC correlated with progression free survival (PFS) in patients with limited stage disease (n = 16, stages 1-3) (HR = 1.35, p = 0.03; HR = 1.45, p = 0.02, respectively). In the tumor, higher PMN-MDSC levels were significantly associated with decreased PFS (n = 29, HR = 1.09, p = 0.011). To assess the role of select chemokines (IL-8, CXCL5, Mip-1α, MCP-1 and Rantes) and of the pro-inflammatory cytokine IL-1β in promoting the accumulation of MDSC within the tumor, these proteins were quantitated in tumor lysates by ELISA and correlated to MDSC frequencies (Spearman correlations). We found a direct correlation between the frequency of PMN-MDSC in the parenchyma and the levels of IL-8 (p < 0.001), CXCL-5 (p < 0.001), and IL-1β (p = 0.029). Frequency of parenchymal Lin- MDSC directly correlated with levels of IL-8 (p = 0.033) and CXCL-5 (p = 0.008), but not IL-1β. In circulation, frequency of total MDSCs directly correlated with IL-1β plasma levels (p = 0.003).\ud \ud To further define the role of IL-1β in MDSC accumulation within tumors, we overexpressed IL-1β in RENCA and CT26 tumors and compared them to untransfected tumors. Overexpression of IL-1β resulted in enhanced tumor growth and increased frequency of intratumor PMN-MDSC (10.3X in RENCA and 26X in CT26), with a modest increase in intratumor M-MDSC. A large fraction of tumor infiltrating PMN-MDSC expressed CXCR2 (84% in RENCA and 55% in CT26), which is associated with a significant increase in expression of CXCR2 ligands (KC, CXCL5, and MIP2). These results support the idea that IL-1β-mediated induction of select chemokines promotes the accumulation of MDSC, particularly PMN-MDSC, within tumors, resulting in enhanced immune suppression and angiogenesis

Sustained silver-releasing dressing in the treatment of diabetic foot ulcers

This study investigated the clinical performance and safety of a sustained silver-releasing foam dressing, Contreet Foam, in the treatment of diabetic foot ulcers. Twenty-seven patients with diabetic foot ulcers of grade I or II (Wagner's classification) were followed for six weeks: one week run-in using Biatain dressings, four weeks' treatment with Contreet dressings. Four ulcers healed during the four-week treatment with Contreet 56% in average. Contreet Foam showed good exudate management properties and was considered easy to use. Only two infections occurred showed that all six of the non-study ulcers developed an infection during the study. All ulcers (study ulcers as well as non-study ulcers) were treated according to good practice of diabetic wound care. There were no directions for the treatment of secondary wounds. No device-related adverse events were observed. This study demonstrated that Contreet Foam is safe and easy to use and effectively supports healing and good wound progress of diabetic foot ulcers

Sustained silver-releasing dressing in the treatment of diabetic foot ulcers

This study investigated the clinical performance and safety of a sustained silver-releasing foam dressing, Contreet Foam, in the treatment of diabetic foot ulcers. Twenty-seven patients with diabetic foot ulcers of grade I or II (Wagner's classification) were followed for six weeks: one week run-in using Biatain dressings, four weeks' treatment with Contreet dressings. Four ulcers healed during the four-week treatment with Contreet 56% in average. Contreet Foam showed good exudate management properties and was considered easy to use. Only two infections occurred showed that all six of the non-study ulcers developed an infection during the study. All ulcers (study ulcers as well as non-study ulcers) were treated according to good practice of diabetic wound care. There were no directions for the treatment of secondary wounds. No device-related adverse events were observed. This study demonstrated that Contreet Foam is safe and easy to use and effectively supports healing and good wound progress of diabetic foot ulcers

Myeloid-specific genetic ablation of ATP-binding cassette transporter ABCA1 is protective against cancer

Increased circulating levels of apolipoprotein A-I (apoA-I), the major protein of high-density lipoprotein (HDL), by genetic manipulation or infusion, protects against melanoma growth and metastasis. Herein, we explored potential roles in melanoma tumorigenesis for host scavenger receptor class B, type 1 (SR-B1), and ATP-binding cassette transporters A1 (ABCA1) and G1 (ABCG1), all mediators of apoA-I and HDL sterol and lipid transport function. In a syngeneic murine melanoma tumor model, B16F10, mice with global deletion of SR-B1 expression exhibited increased plasma HDL cholesterol (HDLc) levels and decreased tumor volume, indicating host SR-B1 does not directly contribute to HDL-associated anti-tumor activity. In mice with myeloid-specific loss of ABCA1 (Abca1-M/-M ; A1-M/-M), tumor growth was inhibited by ∼4.8-fold relative to wild type (WT) animals. Abcg1-M/-M (G1-M/-M) animals were also protected by 2.5-fold relative to WT, with no further inhibition of tumor growth in Abca1/Abcg1 myeloid-specific double knockout animals (DKO). Analyses of tumor-infiltrating immune cells revealed a correlation between tumor protection and decreased presence of the immune suppressive myeloid-derived suppressor cell (MDSC) subsets, Ly-6G+Ly-6CLo and Ly-6GnegLy-6CHi cells. The growth of the syngeneic MB49 murine bladder cancer cells was also inhibited in A1-M/-M mice. Collectively, our studies provide further evidence for an immune modulatory role for cholesterol homeostasis pathways in cancer

Immunotherapy with IL12 and PD1/CTLA4 inhibition is effective in advanced ovarian cancer and associates with reversal of myeloid cell-induced immunosuppression

ABSTRACTThe tumor microenvironment (TME) in ovarian cancer (OC) is characterized by immune suppression, due to an abundance of suppressive immune cells populations. To effectively enhance the activity of immune checkpoint inhibition (ICI), there is a need to identify agents that target these immunosuppressive networks while promoting the recruitment of effector T cells into the TME. To this end, we sought to investigate the effect of the immunomodulatory cytokine IL12 alone or in combination with dual-ICI (anti-PD1 + anti-CTLA4) on anti-tumor activity and survival, using the immunocompetent ID8-VEGF murine OC model. Detailed immunophenotyping of peripheral blood, ascites, and tumors revealed that durable treatment responses were associated with reversal of myeloid cell-induced immune suppression, which resulted in enhanced anti-tumor activity by T cells. Single cell transcriptomic analysis further demonstrated striking differences in the phenotype of myeloid cells from mice treated with IL12 in combination with dual-ICI. We also identified marked differences in treated mice that were in remission compared to those whose tumors progressed, further confirming a pivotal role for the modulation of myeloid cell function to allow for response to immunotherapy. These findings provide the scientific basis for the combination of IL12 and ICI to improve clinical response in OC

Randomised controlled trial of the use of three dressing preparations in the management of chronic ulceration of the foot in diabetes

Objectives: To determine the comparative effectiveness and cost-effectiveness of three dressing products, N-A®, Inadine® and Aquacel®, for patients with diabetic foot ulcers, as well as the feasibility and consequences of less frequent dressing changes by health-care professionals. Design: A multicentre, prospective, observer-blinded, parallel group, randomised controlled trial, with three arms. Setting: Established expert multidisciplinary clinics for the management of diabetic foot ulcers across the UK. Participants: Patients over age 18 with type 1 or type 2 diabetes with a chronic (present for at least 6 weeks) full-thickness foot ulcer (on or below the malleoli) not penetrating to tendon, periosteum or bone, and with a cross-sectional area between 25 and 2500 mm2. Interventions: Participants were randomised 1:1:1 to treatment with one of N-A (a non-adherent, knitted, viscose filament gauze), Inadine (an iodine-impregnated dressing), both traditional dressings, or Aquacel, a newer product. Main outcome measures: The primary outcome measure was the number of ulcers healed in each group at week 24. Secondary measures included time to healing, new ulcerations, major and minor amputations, and episodes of secondary infection. Results: A total of 317 patients were randomised. After 88 withdrawals, 229 remained evaluable. A greater proportion of smaller (25–100 mm2 ulcers healed within the specified time (48.3% versus 37.3%; p = 0.048). There was, however, no difference between the three dressings in terms of percentage healed by 24 weeks, or in the mean time to healing, whether analysed on the basis of intention to treat (Inadine 44.4%, N-A 38.7%, Aquacel 44.7%; not significant) or per protocol (Inadine 55.2%, N-A 59.4%, Aquacel 63.0%; not significant). There was no difference in the quality of healing, as reflected in the incidence of recurrence within 12 weeks. Likewise, there was no difference in the incidence of adverse events, although a greater proportion of those randomised to the non-adherent dressings were withdrawn from the study (34.9% versus 29.1% Aquacel and 19.4% Inadine; p = 0.038). The only statistically significant difference found in the health economic analysis was the cost associated with the provision of dressings (mean cost per patient: N-A £14.85, Inadine £17.48, Aquacel £43.60). The higher cost of Aquacel was not offset by the fewer dressings required. There was no difference in measures of either generic or condition-specific measures of quality of life. However, there was a significant difference in the change in pain associated with dressing changes between the first and second visits, with least pain reported by those receiving non-adherent dressings (p = 0.012). There was no difference in the costs of professional time, and this may relate to the number of dressing changes undertaken by non-professionals. Fifty-one per cent of all participants had at least one dressing change undertaken by themselves or a non-professional carer, although this ranged from 22% to 82% between the different centres. Conclusions: As there was no difference in effectiveness, there is no reason why the least costly of the three dressings could not be used more widely across the UK National Health Service, thus generating potentially substantial savings. The option of involving patients and non-professional carers in changing dressings needs to be assessed more formally and could be associated with further significant reductions in health-care costs. Trial registration: Current Controlled Trials ISRCTN78366977