Genomic Analysis of Immune Cell Infiltrates Across 11 Tumor Types

Background: Immune infiltration of the tumor microenvironment has been associated with improved survival for some patients with solid tumors. The precise makeup and prognostic relevance of immune infiltrates across a broad spectrum of tumors remain unclear

Chemotherapy and Stem Cell Transplantation Increase p16

AbstractThe expression of markers of cellular senescence increases exponentially in multiple tissues with aging. Age-related physiological changes may contribute to adverse outcomes in cancer survivors. To investigate the impact of high dose chemotherapy and stem cell transplantation on senescence markers in vivo, we collected blood and clinical data from a cohort of 63 patients undergoing hematopoietic cell transplantation. The expression of p16INK4a, a well-established senescence marker, was determined in T-cells before and 6months after transplant. RNA sequencing was performed on paired samples from 8 patients pre- and post-cancer therapy. In patients undergoing allogeneic transplant, higher pre-transplant p16INK4a expression was associated with a greater number of prior cycles of chemotherapy received (p=0.003), prior autologous transplantation (p=0.01) and prior exposure to alkylating agents (p=0.01). Transplantation was associated with a marked increase in p16INK4a expression 6months following transplantation. Patients receiving autologous transplant experienced a larger increase in p16INK4a expression (3.1-fold increase, p=0.002) than allogeneic transplant recipients (1.9-fold increase, p=0.0004). RNA sequencing of T-cells pre- and post- autologous transplant or cytotoxic chemotherapy demonstrated increased expression of transcripts associated with cellular senescence and physiological aging. Cytotoxic chemotherapy, especially alkylating agents, and stem cell transplantation strongly accelerate expression of a biomarker of molecular aging in T-cells

Circulating Fibrocytes Prepare the Lung for Cancer Metastasis by Recruiting Ly-6C+ Monocytes Via CCL2

Fibrocytes are circulating, hematopoietic cells that express CD45 and Col1a1. They contribute to wound healing and several fibrosing disorders by mechanisms that are poorly understood. In this report, we demonstrate that fibrocytes predispose the lung to B16-F10 metastasis by recruiting Ly-6C+ monocytes. To do so, we isolated fibrocytes expressing CD45, CD11b, CD13, and Col1a1 from the lungs of wild type (WT) and Ccr5−/− mice. WT but not Ccr5−/− fibrocytes increased the number of metastatic foci when injected into Ccr5−/− mice (73 ± 2 versus 32 ± 5; p < 0.001). This process was MMP9 dependent. Injection of WT enhanced GFP+ fibrocytes also increased the number of Gr-1Int, CD11b+, and enhanced GFP− monocytes. Like premetastatic-niche monocytes, these recruited cells expressed Ly-6C, CD117, and CD45. The transfer of these cells into Ccr5−/− mice enhanced metastasis (90 ± 8 foci) compared with B cells (27 ± 2), immature dendritic cells (31 ± 6), or alveolar macrophages (28 ± 3; p < 0.05). WT and Ccl2−/− fibrocytes also stimulated Ccl2 expression in the lung by 2.07 ± 0.05- and 2.78 ± 0.36-fold compared with Ccr5−/− fibrocytes (1.0 ± 0.06; p < 0.05). Furthermore, WT fibrocytes did not increase Ly-6C+ monocytes in Ccr2−/− mice and did not promote metastasis in either Ccr2−/− or Ccl2−/− mice. These data support our hypothesis that fibrocytes contribute to premetastatic conditioning by recruiting Ly-6C+ monocytes in a chemokine-dependent process. This work links metastatic risk to conditions that mobilize fibrocytes, such as inflammation and wound repair

A colitogenic memory CD4+ T cell population mediates gastrointestinal graft-versus-host disease

Damage to the gastrointestinal tract is a major cause of morbidity and mortality in graft-versus-host disease (GVHD) and is attributable to T cell–mediated inflammation. In this work, we identified a unique CD4+ T cell population that constitutively expresses the β2 integrin CD11c and displays a biased central memory phenotype and memory T cell transcriptional profile, innate-like properties, and increased expression of the gut-homing molecules α4β7 and CCR9. Using several complementary murine GVHD models, we determined that adoptive transfer and early accumulation of β2 integrin–expressing CD4+ T cells in the gastrointestinal tract initiated Th1-mediated proinflammatory cytokine production, augmented pathological damage in the colon, and increased mortality. The pathogenic effect of this CD4+ T cell population critically depended on coexpression of the IL-23 receptor, which was required for maximal inflammatory effects. Non–Foxp3-expressing CD4+ T cells produced IL-10, which regulated colonic inflammation and attenuated lethality in the absence of functional CD4+Foxp3+ T cells. Thus, the coordinate expression of CD11c and the IL-23 receptor defines an IL-10–regulated, colitogenic memory CD4+ T cell subset that is poised to initiate inflammation when there is loss of tolerance and breakdown of mucosal barriers

Type 2 innate lymphoid cells treat and prevent acute gastrointestinal graft-versus-host disease

Acute graft-versus-host disease (aGVHD) is the most common complication for patients undergoing allogeneic stem cell transplantation. Despite extremely aggressive therapy targeting donor T cells, patients with grade III or greater aGVHD of the lower GI tract, who do not respond to therapy with corticosteroids, have a dismal prognosis. Thus, efforts to improve understanding of the function of local immune and non-immune cells in regulating the inflammatory process in the GI tract during aGVHD are needed. Here, we demonstrate, using murine models of allogeneic BMT, that type 2 innate lymphoid cells (ILC2s) in the lower GI tract are sensitive to conditioning therapy and show very limited ability to repopulate from donor bone marrow. Infusion of donor ILC2s was effective in reducing the lethality of aGVHD and in treating lower GI tract disease. ILC2 infusion was associated with reduced donor proinflammatory Th1 and Th17 cells, accumulation of donor myeloid-derived suppressor cells (MDSCs) mediated by ILC2 production of IL-13, improved GI tract barrier function, and a preserved graft-versus-leukemia (GVL) response. Collectively, these findings suggest that infusion of donor ILC2s to restore gastrointestinal tract homeostasis may improve treatment of severe lower GI tract aGVHD

C-C Chemokine Receptor 5 on Pulmonary Mesenchymal Cells Promotes Experimental Metastasis via the Induction of Erythroid Differentiation Regulator 1

C-C Chemokine receptor five knockout (Ccr5-/-) mice develop fewer experimental pulmonary metastases than wild type (WT) mice. This phenomenon was explored by applying gene-expression profiling to the lungs of mice with these metastases. Consequently, Erythroid Differentiation Regulator 1 (Erdr1) was identified as upregulated in the WT mice. Though commonly associated with bone marrow stroma, Erdr1 was differentially expressed in WT pulmonary mesenchymal cells (PMCs) and murine embryonic fibroblasts (MEFs). Moreover, the Ccr5 ligand Ccl4 increased its expression by 3.36 ± 0.14 fold. Ccr5 signaling was dependent on the Map2k but not the Pi3k pathway since treatment with U0126 inhibited upregulation of Erdr1 but treatment with LY294002 increased the expression by 3.44 ± 0.92 fold (p < 0.05). Erdr1's effect on B16-F10 melanoma metastasis was verified by the adoptive transfer of WT MEFs into Ccr5-/- mice. In this model, MEFs that had been transduced with Erdr1 shRNA lowered metastasis by 33% compared to control transduced MEFs. The relevance of ERDR1 on human disease was assessed by co-culturing chronic lymphocytic leukemia (CLL) cells with M2-10B4 stromal cells that had been transfected with shRNA or control plasmids. After 96 hours of co-culture, the cell counts were higher with control cell lines compared with Erdr1 knockdown lines (OR 1.88 ± 0.27, 2.52 ± 0.66 respectively). This increase was associated with a decrease in apoptotic cells (OR 0.69 ± 0.18, 0.58 ± 0.12 respectively)

Cytoprotection by Amifostine during Autologous Stem Cell Transplantation for Advanced Refractory Hematologic Malignancies

Abstract This study evaluated whether amifostine protects against mucositis and other toxicities in patients with advanced, refractory, or recurrent hematologic malignancies undergoing high-dose chemotherapy and total body irradiation. Thirty-five patients (20 with non-Hodgkin lymphoma, 12 with Hodgkin disease, and 3 with acute myelogenous leukemia) who underwent autologous stem cell transplantation were conditioned with total body irradiation 2 Gy twice daily on days −8 through −6; cyclophosphamide 6 g/m2, etoposide 1.8 g/m2, and carboplatin 1 g/m2 on days −5 through −3; and amifostine 500 mg/m2 on days −8 through −2. Prior institutional experience in patients treated without amifostine was used as a historical comparison (no-amifostine group). Severe mucositis occurred in 14 (40%) of 35 patients in the amifostine group, compared with 33 (94%) of 35 in the no-amifostine group (P < .0001). Total parenteral nutrition was used by 4 (11%) of 35 amifostine-treated patients and 34 (97%) of 35 no-amifostine patients (P < .0001). The median duration of narcotic use decreased from 15.5 days with no amifostine to 11 days with amifostine (P = .002). Granulocyte and platelet engraftment times were similar. Prospective trials with innovative designs and clearly defined stopping rules are warranted to confirm whether amifostine reduces the toxicities of a myelosuppressive conditioning regimen before autologous stem cell transplantation without compromising therapeutic response

Phase II Trial of Pembrolizumab after High-Dose Cytarabine in Relapsed/Refractory Acute Myeloid Leukemia.

UNLABELLED: Immune suppression, exhaustion, and senescence are frequently seen throughout disease progression in acute myeloid leukemia (AML). We conducted a phase II study of high-dose cytarabine followed by pembrolizumab 200 mg i.v. on day 14 to examine whether PD-1 inhibition improves clinical responses in relapsed/refractory (R/R) AML. Overall responders could receive pembrolizumab maintenance up to 2 years. Among 37 patients enrolled, the overall response rate, composite complete remission (CRc) rate (primary endpoint), and median overall survival (OS) were 46%, 38%, and 11.1 months, respectively. Patients with refractory/early relapse and those receiving treatment as first salvage had encouraging outcomes (median OS, 13.2 and 11.3 months, respectively). Grade ≥3 immune-related adverse events were rare (14%) and self-limiting. Patients who achieved CRc had a higher frequency of progenitor exhausted CD8+ T cells expressing TCF-1 in the bone marrow prior to treatment. A multifaceted correlative approach of genomic, transcriptomic, and immunophenotypic profiling offers insights on molecular correlates of response and resistance to pembrolizumab. SIGNIFICANCE: Immune-checkpoint blockade with pembrolizumab was tolerable and feasible after high-dose cytarabine in R/R AML, with encouraging clinical activity, particularly in refractory AML and those receiving treatment as first salvage regimen. Further study of pembrolizumab and other immune-checkpoint blockade strategies after cytotoxic chemotherapy is warranted in AML.See related commentary by Wei et al., p. 551. This article is highlighted in the In This Issue feature, p. 549