Conversion of cancer-associated fibroblasts from pro- to antitumor improves the sensitivity of pancreatic cancer to chemotherapeutics

Previous therapeutic attempts to deplete cancer-associated fibroblasts (CAFs) or inhibit their proliferation in pancreatic ductal adenocarcinoma (PDAC) were not successful in mice or patients. Thus, CAFs may be tumor suppressive or heterogeneous, with distinct cancer-restraining and -promoting CAFs (rCAFs and pCAFs, respectively). Here, we show that induced expression of the glycosylphosphatidylinositol-anchored protein Meflin, a rCAF-specific marker, in CAFs by genetic and pharmacological approaches improved the chemosensitivity of mouse PDAC. A chemical library screen identified Am80, a synthetic, non-natural retinoid, as a reagent that effectively induced Meflin expression in CAFs. Am80 administration improved the sensitivity of PDAC to chemotherapeutics, accompanied by increases in tumor vessel area and intratumoral drug delivery. Mechanistically, Meflin was involved in the suppression of tissue stiffening by interacting with lysyl oxidase to inhibit its collagen crosslinking activity. These data suggested that modulation of CAF heterogeneity may represent a strategy for PDAC treatment.

Influence of injection technique, drug formulation and tumor microenvironment on intratumoral immunotherapy delivery and efficacy

BackgroundIntratumoral delivery of immunotherapeutics represents a compelling solution to directly address local barriers to tumor immunity. However, we have previously shown that off-target delivery is a substantial problem during intratumoral injections; this can lead to diminished drug efficacy and systemic toxicities. We have identified three variables that influence intratumoral drug delivery: injection technique, drug formulation and tumor microenvironment. The purpose of this study was to characterize the impact of modifications in each variable on intratumoral drug delivery and immunotherapy efficacy.MethodsIntratumoral injections were performed in a hybrid image-guided intervention suite with ultrasound, fluoroscopy and CT scanning capabilities in both rat and mouse syngeneic tumor models. Intratumoral drug distribution was quantified by CT volumetric imaging. The influence of varying needle design and hydrogel-based drug delivery on the immune response to a stimulator of interferon genes (STING) agonist was evaluated using flow cytometry and single cell RNA sequencing. We also evaluated the influence of tumor stiffness on drug injection distribution.ResultsVariations in needle design, specifically with the use of a multiside hole needle, led to approximately threefold improvements in intratumoral drug deposition relative to conventional end-hole needles. Likewise, delivery of a STING agonist through a multiside hole needle led to significantly increased expression of type I interferon-associated genes and ‘inflammatory’ dendritic cell gene signatures relative to end-hole STING agonist delivery. A multidomain peptide-based hydrogel embedded with a STING agonist led to substantial improvements in intratumoral deposition; however, the hydrogel was noted to generate a strong immune response against itself within the target tumor. Evaluation of tumor stroma on intratumoral drug delivery revealed that there was a greater than twofold improvement in intratumoral distribution in soft tumors (B16 melanoma) compared with firm tumors (MC38 colorectal).ConclusionsInjection technique, drug formulation and tumor stiffness play key roles in the accurate delivery of intratumoral immunotherapeutics.

Intratumoral injection of hydrogel-embedded nanoparticles enhances retention in glioblastoma

Intratumoral drug delivery is a promising approach for the treatment of glioblastoma multiforme (GBM).

Optimized intratumoral delivery of a STING agonist results in improvements in local tumor immune activation.

38 Background: There has been a renaissance in the concept of promoting the immune-responsiveness of the tumor immune microenvironment via intratumoral (IT) delivery of immunostimulatory agents. As with any invasive intervention, though, outcomes following intratumoral drug delivery depend on procedural technique. We have previously shown that multi-sidehole needles (MSHNs) provide a 3-fold improvement in intratumoral drug delivery and retention relative to conventional end-hole needles (EHNs). The purpose of this study was to characterize how variations in drug delivery affect drug efficacy by evaluating immune activation following the IT delivery of a STING agonist using conventional end-hole needles (EHNs) versus multi-sidehole needles (MSHNs). Methods: Syngeneic McArdle RH-7777 (ATCC) hepatoma cells were implanted in the flank of Buffalo rats (n=20). Once tumors reached 15-20 mm in size, a STING agonist (50 ug ML RR-S2 CDA, Sigma Aldrich) vs saline (control) was injected under ultrasound visualization using either a 22G EHN or a 21G MSHN (ProFusion, Cook Regentec). Tumor tissue was harvested at 24 and 48 hours post-injection. Immune profiling was performed using flow cytometry and single cell RNA sequencing (scRNAseq). Results: There was a significant increase in tumor necrosis with MSHN injections compared to EHN or control injections (tumor viability 32%, 54%, and 82% at 48 hours, respectively). Gene expression profiling demonstrated a significant increase in interferon sensitive genes as well as STING-TBK1-IRF3 axis genes within dendritic cells with MSHN injections compared to EHN or control injections (Table). This signaling upregulation was greater at 24 hours than at 48 hours. MSHN injected tumors also exhibited fewer macrophages with immunosuppressive gene signatures and fewer T cells with exhaustion gene signatures relative to EHN or control tumors. Conclusions: Variations in IT delivery technique have a significant impact on subsequent immune activation following the injection of a STING agonist in an animal model of HCC. [Table: see text]

Mesoporous iron-carboxylate metal–organic frameworks synthesized by the double-template method as a nanocarrier platform for intratumoral drug delivery

The DOX-loaded mesoMOFs exhibit excellent therapeutic efficacy and low side effects in local chemotherapy.