Immune checkpoint therapy with anti-CTLA-4 and anti-PD-1/PD-L1 has revolutionized the treatment of many solid tumors. However, the clinical efficacy of immune checkpoint therapy is limited to a ...subset of patients with specific tumor types
. Multiple clinical trials with combinatorial immune checkpoint strategies are ongoing; however, the mechanistic rationale for tumor-specific targeting of immune checkpoints is elusive. To garner an insight into tumor-specific immunomodulatory targets, we analyzed 94 patients representing five different cancer types, including those that respond relatively well to immune checkpoint therapy and those that do not, such as glioblastoma multiforme, prostate cancer and colorectal cancer. Through mass cytometry and single-cell RNA sequencing, we identified a unique population of CD73
macrophages in glioblastoma multiforme that persists after anti-PD-1 treatment. To test if targeting CD73 would be important for a successful combination strategy in glioblastoma multiforme, we performed reverse translational studies using CD73
mice. We found that the absence of CD73 improved survival in a murine model of glioblastoma multiforme treated with anti-CTLA-4 and anti-PD-1. Our data identified CD73 as a specific immunotherapeutic target to improve antitumor immune responses to immune checkpoint therapy in glioblastoma multiforme and demonstrate that comprehensive human and reverse translational studies can be used for rational design of combinatorial immune checkpoint strategies.
Obesity is a prognostic risk factor in the progression of prostate cancer; however, the molecular mechanisms involved are unclear. In this study, we provide preclinical proof of concept for the role ...of a proinflammatory CXCL12-CXCR4/CXCR7 signaling axis in an obesity-driven mouse model of myc-induced prostate cancer. Analysis of the stromal vascular fraction from periprostatic white adipose tissue from obese HiMyc mice at 6 months of age revealed a dramatic increase in mRNAs encoding various chemokines, cytokines, growth factors, and angiogenesis mediators, with CXCL12 among the most significantly upregulated genes. Immunofluorescence staining of ventral prostate tissue from obese HiMyc mice revealed high levels of CXCL12 in the stromal compartment as well as high staining for CXCR4 and CXCR7 in the epithelial compartment of tumors. Prostate cancer cell lines derived from HiMyc tumors (HMVP2 and derivative cell lines) displayed increased protein expression of both CXCR4 and CXCR7 compared with protein lysates from a nontumorigenic prostate epithelial cell line (NMVP cells). CXCL12 treatment stimulated migration and invasion of HMVP2 cells but not NMVP cells. These effects of CXCL12 on HMVP2 cells were inhibited by the CXCR4 antagonist AMD3100 as well as knockdown of either CXCR4 or CXCR7. CXCL12 treatment also produced rapid activation of STAT3, NFκB, and MAPK signaling in HMVP2 cells, which was again attenuated by either AMD3100 or knockdown of CXCR4 or CXCR7. Collectively, these data suggest that CXCL12 secreted by stromal cells activates invasiveness of prostate cancer cells and may play a role in driving tumor progression in obesity. Targeting the CXCL12-CXCR4/CXCR7 axis could lead to novel approaches for offsetting the effects of obesity on prostate cancer progression.
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We report the first case series of immune checkpoint inhibitors (ICI)-associated colitis successfully treated with fecal microbiota transplantation, with reconstitution of the gut microbiome and a ...relative increase in the proportion of regulatory T-cells within the colonic mucosa. These preliminary data provide evidence that modulation of the gut microbiome may abrogate ICI-associated colitis.
Preclinical models have shown that blocking PD-1/PD-L1 pathways enhances antileukemic responses. Azacitidine upregulates PD-1 and IFNγ signaling. We therefore conducted this single-arm trial, in ...which patients with relapsed/refractory (R/R) acute myeloid leukemia (AML) were treated with azacitidine 75 mg/m
days 1 to 7 intravenously or subcutaneously with nivolumab 3 mg/kg intravenously on days 1 and 14, every 4 to 6 weeks. For the seventy patients who were treated, the median age was 70 years (range, 22-90) and the median number of prior therapies received was 2 (range, 1-7). The overall response rate (ORR) was 33%, including 15 (22%) complete remission/complete remission with insufficient recovery of counts, 1 partial response, and 7 patients with hematologic improvement maintained >6 months. Six patients (9%) had stable disease >6 months. The ORR was 58% and 22%, in hypomethylating agent (HMA)-naïve (
= 25) and HMA-pretreated (
= 45) patients, respectively. Grade 3 to 4 immune-related adverse events occurred in 8 (11%) patients. Pretherapy bone marrow and peripheral blood CD3 and CD8 were significantly predictive for response on flow cytometry. CTLA4 was significantly upregulated on CD4
Teff in nonresponders after 2 and 4 doses of nivolumab. Azacitidine and nivolumab therapy produced an encouraging response rate and overall survival in patients with R/R AML, particularly in HMA-naïve and salvage 1 patients. Pretherapy bone marrow aspirate and peripheral blood CD3 percentage may be biomarkers for patient selection. SIGNIFICANCE: Azacitidine in combination with nivolumab appeared to be a safe and effective therapy in patients with AML who were salvage 1, prior hypomethylator-naïve, or had increased pretherapy CD3
bone marrow infiltrate by flow cytometry or IHC. Bone marrow CD3 and CD8 are relatively simple assays that should be incorporated to select patients in future trials.
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Combination therapy with α-CTLA-4 and α-PD-1 has shown significant clinical responses in different types of cancer. However, the underlying mechanisms remain elusive. Here, combining detailed ...analysis of human tumour samples with preclinical tumour models, we report that concomitant blockade of CTLA-4 and PD-1 improves anti-tumour immune responses and synergistically eradicates tumour. Mechanistically, combination therapy relies on the interdependence between IL-7 and IFN-γ signalling in T cells, as lack of either pathway abrogates the immune-boosting and therapeutic effects of combination therapy. Combination treatment increases IL-7Rα expression on tumour-infiltrating T cells in an IFN-γ/IFN-γR signalling-dependent manner, which may serve as a potential biomarker for clinical trials with immune checkpoint blockade. Our data suggest that combining immune checkpoint blockade with IL-7 signalling could be an effective modality to improve immunotherapeutic efficacy. Taken together, we conclude that combination therapy potently reverses immunosuppression and eradicates tumours via an intricate interplay between IFN-γ/IFN-γR and IL-7/IL-7R pathways.
Immune checkpoint therapy is being tested in the neoadjuvant setting for patients with localized urothelial carcinoma
, with one study reporting data in cisplatin-ineligible patients who received ...anti-PD-L1 monotherapy
. The study reported that patients with bulky tumors, a known high-risk feature defined as greater than clinical T2 disease, had fewer responses, with pathological complete response rate of 17%
. Here we report on the first pilot combination neoadjuvant trial ( NCT02812420 ) with anti-PD-L1 (durvalumab) plus anti-CTLA-4 (tremelimumab) in cisplatin-ineligible patients, with all tumors identified as having high-risk features (n = 28). High-risk features were defined by bulky tumors, variant histology, lymphovascular invasion, hydronephrosis and/or high-grade upper tract disease
. The primary endpoint was safety and we observed 6 of 28 patients (21%) with grade ≥3 immune-related adverse events, consisting of asymptomatic laboratory abnormalities (n = 4), hepatitis and colitis (n = 2). We also observed pathological complete response of 37.5% and downstaging to pT1 or less in 58% of patients who completed surgery (n = 24). In summary, we provide initial safety, efficacy and biomarker data with neoadjuvant combination anti-PD-L1 plus anti-CTLA-4, which warrants further development for patients with localized urothelial carcinoma, especially cisplatin-ineligible patients with high-risk features who do not currently have an established standard-of-care neoadjuvant treatment.
Immune checkpoint therapy (ICT) has transformed cancer treatment in recent years; however, treatment response is not uniform across tumor types. The tumor immune microenvironment plays a critical ...role in determining response to ICT; therefore, understanding the differential immune infiltration between ICT-sensitive and ICT-resistant tumor types will help to develop effective treatment strategies. We performed a comprehensive analysis of the immune tumor microenvironment of an ICT-sensitive tumor (melanoma, n = 44) and an ICT-resistant tumor (pancreatic cancer, n = 67). We found that a pancreatic tumor has minimal tomoderate infiltration of CD3, CD4, and CD8 T cells; however, the immune infiltrates are predominantly present in the stromal area of the tumor and are excluded from tumoral area compared with melanoma, where the immune infiltrates are primarily present in the tumoral area. Metastatic pancreatic ductal adenocarcinomas (PDACs) had a lower infiltration of total T cells compared with resectable primary PDACs, suggesting that metastatic PDACs have poor immunogenicity. Further, a significantly higher number of CD68⁺ macrophages and VISTA⁺ cells (also known as V-domain immunoglobulin suppressor of T cell activation) were found in the pancreatic stromal area compared with melanoma. We identified VISTA as a potent inhibitory checkpoint that is predominantly expressed on CD68+ macrophages on PDACs. These data suggest that VISTA may be a relevant immunotherapy target for effective treatment of patients with pancreatic cancer.
Immune checkpoint therapy (ICT) can produce durable antitumor responses in metastatic urothelial carcinoma (mUCC); however, the responses are not universal. Despite multiple approvals of ICT in mUCC, ...we lack predictive biomarkers to guide patient selection. The identification of biomarkers may require interrogation of both the tumor mutational status and the immune microenvironment. Through multi-platform immuno-genomic analyses of baseline tumor tissues, we identified the mutation of AT-rich interactive domain-containing protein 1A (
) in tumor cells and expression of immune cytokine CXCL13 in the baseline tumor tissues as two predictors of clinical responses in a discovery cohort (
= 31). Further, reverse translational studies revealed that CXCL13
tumor-bearing mice were resistant to ICT, whereas
knockdown enhanced sensitivity to ICT in a murine model of bladder cancer. Next, we tested the clinical relevance of
mutation and baseline CXCL13 expression in two independent confirmatory cohorts (CheckMate275 and IMvigor210). We found that
mutation and expression of CXCL13 in the baseline tumor tissues correlated with improved overall survival (OS) in both confirmatory cohorts (CheckMate275, CXCL13 data,
= 217; ARID1A data,
= 139, and IMvigor210, CXCL13 data,
= 348; ARID1A data,
= 275). We then interrogated CXCL13 expression plus
mutation as a combination biomarker in predicting response to ICT in CheckMate275 and IMvigor210. Combination of the two biomarkers in baseline tumor tissues suggested improved OS compared to either single biomarker. Cumulatively, this study revealed that the combination of CXCL13 plus ARID1A may improve prediction capability for patients receiving ICT.
PKCε, an oncogenic member of the PKC family, is aberrantly overexpressed in epithelial cancers. To date, little is known about functional interactions of PKCε with other genetic alterations, as well ...as the effectors contributing to its tumorigenic and metastatic phenotype. Here, we demonstrate that PKCε cooperates with the loss of the tumor suppressor Pten for the development of prostate cancer in a mouse model. Mechanistic analysis revealed that PKCε overexpression and Pten loss individually and synergistically upregulate the production of the chemokine CXCL13, which involves the transcriptional activation of the CXCL13 gene via the non-canonical nuclear factor κB (NF-κB) pathway. Notably, targeted disruption of CXCL13 or its receptor, CXCR5, in prostate cancer cells impaired their migratory and tumorigenic properties. In addition to providing evidence for an autonomous vicious cycle driven by PKCε, our studies identified a compelling rationale for targeting the CXCL13-CXCR5 axis for prostate cancer treatment.
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•PKCε overexpression in a Pten-deficient background promotes prostate cancer in mice•This cooperation confers a highly proliferative, migratory, and invasive phenotype•PKCε overexpression with Pten loss leads to CXCL13 upregulation via NF-κB•Elevated CXCL13 mediates migratory and tumorigenic activity of prostate cancer cells
Garg et al. find that PKCε overexpression cooperates with Pten loss to promote prostate cancer in mice. These two alterations together confer enhanced growth, tumorigenic, migratory and invasive capabilities to prostate epithelial cells, and promote the release of CXCL13, an effect that is mediated by the non-canonical NF-κB pathway.
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