Next-generation biological vector platforms for in vivo delivery of genome editing agents

CRISPR-based genome editing holds promise for addressing genetic disease, infectious disease, and cancer and has rapidly advanced from primary research to clinical trials in recent years. However, the lack of safe and potent in vivo delivery methods for CRISPR components has limited most ongoing clinical trials to ex vivo gene therapy. Effective CRISPR in vivo genome editing necessitates an effective vehicle ensuring target cell transduction while minimizing off-target effects, toxicity, and immune reactions. In this review, we examine promising biological-derived platforms to deliver DNA editing agents in vivo and the engineering thereof, encompassing potent viral-based vehicles, flexible protein nanocages, and mammalian-derived particles.

Advanced Glycation End Products as a Potential Target for Restructuring the Ovarian Cancer Microenvironment: A Pilot Study

Ovarian cancer is the sixth leading cause of cancer-related death in women, and both occurrence and mortality are increased in women over the age of 60. There are documented age-related changes in the ovarian cancer microenvironment that have been shown to create a permissive metastatic niche, including the formation of advanced glycation end products, or AGEs, that form crosslinks between collagen molecules. Small molecules that disrupt AGEs, known as AGE breakers, have been examined in other diseases, but their efficacy in ovarian cancer has not been evaluated. The goal of this pilot study is to target age-related changes in the tumor microenvironment with the long-term aim of improving response to therapy in older patients. Here, we show that AGE breakers have the potential to change the omental collagen structure and modulate the peritoneal immune landscape, suggesting a potential use for AGE breakers in the treatment of ovarian cancer.

Another Wrinkle with Age: Aged Collagen and Intra-peritoneal Metastasis of Ovarian Cancer

Background

Age is the most significant risk factor for ovarian cancer (OvCa), the deadliest gynecologic malignancy. Metastasizing OvCa cells adhere to the omentum, a peritoneal structure rich in collagen, adipocytes, and immune cells. Ultrastructural changes in the omentum and the omental collagen matrix with aging have not been evaluated.

Aim

The aim of this study was to test the hypothesis that age-related changes in collagen in the ovarian tumor microenvironment promote OvCa metastatic success in the aged host.

Methods/Results

Young (3-6 months) and aged mice (20-23 months) were used to study the role of aging in metastatic success. Intra-peritoneal (IP) injection of ID8Trp53 ^-/- ovarian cancer cells showed enhanced IP dissemination in aged vs young mice. In vitro assays using purified collagen demonstrated reduced collagenolysis of aged fibers, as visualized using scanning electron microscopy (SEM) and quantified with a hydroxyproline release assay. Omental tumors in young and aged mice showed similar collagen deposition; however enhanced intra-tumoral collagen remodeling was seen in aged mice probed with a biotinylated collagen hybridizing peptide (CHP). In contrast, second harmonic generation (SHG) microscopy showed significant differences in collagen fiber structure and organization in omental tissue and SEM demonstrated enhanced omental fenestration in aged omenta. Combined SHG and Alexa Fluor-CHP microscopy in vivo demonstrated that peri-tumoral collagen was remodeled more extensively in young mice. This collagen population represents truly aged host collagen, in contrast to intra-tumoral collagen that is newly synthesized, likely by cancer associated fibroblasts (CAFs).

Conclusions

Our results demonstrate that tumors in an aged host can grow with minimal collagen remodeling, while tumors in the young host must remodel peri-tumoral collagen to enable effective proliferation, providing a mechanism whereby age-induced ultrastructural changes in collagen and collagen-rich omenta establish a permissive pre-metastatic niche contributing to enhanced OvCa metastatic success in the aged host.

An Optogenetic Tool to Raise Intracellular pH in Single Cells and Drive Localized Membrane Dynamics

Intracellular pH (pHi) dynamics are critical for regulating normal cell physiology. For example, transient increases in pHi (7.2–7.6) regulate cell behaviors like cell polarization, actin cytoskeleton remodeling, and cell migration. Most studies on pH-dependent cell behaviors have been performed at the population level and use nonspecific methods to manipulate pHi. The lack of tools to specifically manipulate pHi at the single-cell level has hindered investigation of the role of pHi dynamics in driving single cell behaviors. In this work, we show that Archaerhodopsin (ArchT), a light-driven outward proton pump, can be used to elicit robust and physiological pHi increases over the minutes time scale. We show that activation of ArchT is repeatable, enabling the maintenance of high pHi in single cells for up to 45 minutes. We apply this spatiotemporal pHi manipulation tool to determine whether increased pHi is a sufficient driver of membrane ruffling in single cells. Using the ArchT tool, we show that increased pHi in single cells can drive localized membrane ruffling responses within seconds and increased membrane dynamics (both protrusion and retraction events) compared to unstimulated ArchT cells as well as control cells. Overall, this tool allows us to directly investigate the relationship between increased pHi and single cell behaviors such as membrane ruffling. This tool will be transformative in facilitating experiments that are required to determine roles for increased pHi in driving single cell behaviors.