Sialoglycans have emerged as an important immune checkpoint orthogonal to the PD-1/PD-L1 axis. We engineered a novel first-in-class drug candidate (Bi-Sialidase), consisting of an engineered human sialidase (Neu2) Fc fusion, to degrade immunosuppressive sialoglycans. Bi-Sialidase potentiates T cell immune response and demonstrates single-agent antitumor activity and a wide safety margin in preclinical animal models, offering a novel immunomodulatory approach to treat cancer. 

Bispecific T cell engager (BiTE)-based cancer therapies that activate T cells of a patient’s own immune system have had success in treating blood cancers, but with limited efficacy in targeting solid tumors. Here, I will discuss the development of BiTE-sialidase fusion proteins that enhance tumor cell susceptibility to BiTE-mediated cytolysis by T cells via targeted desialylation at the T cell-tumor cell interface.

• What are non-coding regions or the ‘dark matter’ of the genome?
• Guiding clinical treatment
• Future of this field

Adoptive cell therapy (ACT) with genetically modified T cells is a promising approach, however, the tumor microenvironment can establish several obstacles. We develop engineered fusion proteins (FPs) that combine a receptor ectodomain with a different costimulatory endodomain. Intentionally engineered FPs can “armor” T cells by multiple mechanisms and new generations also promote endogenous antitumor immunity, resulting in significantly improved therapeutic efficacy against hematological and solid tumors.

We performed multiple genome-wide CRISPR screens under different immunosuppressive conditions to identify genes that can be targeted to prevent T cell dysfunction. These screens converged on RASA2, a RasGAP that we identify as a signaling checkpoint in human T cells. RASA2 ablation in T cells enhanced signaling and cytolytic activity in response to target antigen, as well as persistent effector function in the setting of repeated tumor antigen stimulations. Ablation of RASA2 in multiple preclinical models of T cell receptor and CAR T cell therapies prolonged survival in mice xenografted with either liquid or solid tumors.

Here we describe a system, called BEHAV3D, developed to study the dynamic interactions of immune cells and patient cancer organoids by means of imaging and transcriptomics. We apply BEHAV3D to live-track >150,000 engineered T cells cultured with patient-derived, solid-tumor organoids, identifying a ‘super engager’ behavioral cluster comprising T cells with potent serial killing capacity.

We have employed three different successful pipelines for discovering what so-called “orphan T cells” recognize and applied these to dissect what dominant persistent anti-cancer T cells recognize during successful immunotherapy for solid cancer. This work has uncovered a new, unanticipated, mode of T cell recognition. I will discuss these results and how they point to potentially exploitable correlates of success.

The engineering of autologous patient T cells for adoptive cell therapies has revolutionized the treatment of several types of cancer1. However, further improvements are needed to increase response and cure rates. CRISPR-based loss-of-function screens have been limited to negative regulators of T cell functions2,3,4 and raise safety concerns owing to the permanent modification of the genome. Here we identify positive regulators of T cell functions through overexpression of around 12,000 barcoded human open reading frames (ORFs).

Effective cellular therapies for solid tumors remain elusive. We present a highly scalable platform to rapidly associate large pools of T cell genetic modifications with high-dimensional single-cell phenotypes across diverse disease contexts. The resulting genotype x phenotype maps have nominated unique novel cell therapy targets with improved in vitro and in vivo performance for further clinical development.

Current CAR T cells fail to discriminate between cells expressing high and low levels of antigens which limits its use against solid tumors. We are engineering T cell circuits that can sense antigen density with an ultrasensitive tunable response. We have designed a two-step recognition-activation circuit where an initial recognition event, via a Synthetic Notch receptor, alters the potency of a subsequent response, CAR expression, and activation.

Synthetic biology is driving a new era of medicine through the genetic programming of living cells. This transformative approach allows for the creation of engineered systems that intelligently sense and respond to diverse environments, ultimately adding specificity and efficacy that extends beyond the capabilities of molecular-based therapeutics. One focus has been on engineering bacteria for cancer therapy, where several studies have demonstrated selective bacterial colonization of solid tumors, primarily due to reduced immune surveillance in tumor cores. In this talk, I will discuss efforts in programming bacterial safety systems and delivery of therapeutic payloads ranging from cytotoxic to immunomodulatory agents.