Phase I Trial Combining Chemokine-Targeting with Loco-Regional Chemoimmunotherapy for Recurrent, Platinum-Sensitive Ovarian Cancer Shows Induction of CXCR3 Ligands and Markers of Type 1 Immunity.

PURPOSE: Increased prevalence of cytotoxic T lymphocytes (CTL) in the tumor microenvironment (TME) predicts positive outcomes in patients with epithelial ovarian cancer (EOC), whereas the regulatory T cells (Treg) predict poor outcomes. Guided by the synergistic activity of TLR3 ligands, IFNα, and COX-2 blockers in selectively enhancing CTL-attractants but suppressing Treg-attractants, we tested a novel intraperitoneal chemoimmunotherapy combination (CITC), to assess its tolerability and TME-modulatory impact in patients with recurrent EOC. PATIENTS AND METHODS: Twelve patients were enrolled in phase I portion of the trial NCT02432378, and treated with intraperitoneal cisplatin, intraperitoneal rintatolimod (dsRNA, TLR3 ligand), and oral celecoxib (COX-2 blocker). Patients in cohorts 2, 3, and 4 also received intraperitoneal IFNα at 2, 6, and 18 million units (MU), respectively. Primary objectives were to evaluate safety, identify phase 2 recommended dose (P2RD), and characterize changes in the immune TME. Peritoneal resident cells and intraperitoneal wash fluid were profiled via NanoString and Meso Scale Discovery (MSD) multiplex assay, respectively. RESULTS: The P2RD of IFNα was 6 MU. Median progression-free survival and overall survival were 8.4 and 30 months, respectively. Longitudinal sampling of the peritoneal cavity via intraperitoneal washes demonstrated local upregulation of IFN-stimulated genes (ISG), including CTL-attracting chemokines (CXCL-9, -10, -11), MHC I/II, perforin, and granzymes. These changes were present 2 days after chemokine modulation and subsided within 1 week. CONCLUSIONS: The chemokine-modulating intraperitoneal-CITC is safe, tolerable, and associated with ISG changes that favor CTL chemoattraction and function. This combination (plus DC vaccine) will be tested in a phase II trial. See related commentary by Aranda et al., p. 1993.

Multiple maternal proteins coordinate to restrict the translation of C. elegans nanos-2 to primordial germ cells.

Although germ cell formation has been relatively well understood in worms and insects, how germ cell-specific developmental programs are initiated is not clear. In Caenorhabditis elegans, translational activation of maternal nos-2 mRNA is the earliest known molecular event specific to the germline founder cell P(4). Cis-elements in nos-2 3'UTR have been shown to mediate translational control; however, the trans-acting proteins are not known. Here, we provide evidence that four maternal RNA-binding proteins, OMA-1, OMA-2, MEX-3 and SPN-4, bind nos-2 3'UTR to suppress its translation, and POS-1, another maternal RNA-binding protein, relieves this suppression in P(4). The POS-1: SPN-4 ratio in P(4) increases significantly over its precursor, P(3); and POS-1 competes with SPN-4 for binding to nos-2 RNA in vitro. We propose temporal changes in the relative concentrations of POS-1 and SPN-4, through their effect on the translational status of maternal mRNAs such as nos-2, initiate germ cell-specific developmental programs in C. elegans.