Design, Synthesis, and Biological Evaluation of the First Inhibitors of Oncogenic CHD1L.

Chromodomain helicase DNA-binding protein 1 like (CHD1L) is an oncogene implicated in tumor progression, multidrug resistance, and metastasis in many types of cancer. In this article, we described the optimization of the first lead CHD1L inhibitors (CHD1Li) through drug design and medicinal chemistry. More than 30 CHD1Li were synthesized and evaluated using a variety of colorectal cancer (CRC) tumor organoid models and functional assays. The results led to the prioritization of six lead CHD1Li analogues with improved potency, antitumor activity, and drug-like properties including metabolic stability and in vivo pharmacokinetics. Furthermore, lead CHD1Li 6.11 proved to be an orally bioavailable antitumor agent, significantly reducing the tumor volume of CRC xenografts generated from isolated quasi mesenchymal cells (M-phenotype), which possess enhanced tumorigenic properties. In conclusion, we reported the optimization of first-in-class inhibitors of oncogenic CHD1L as a novel therapeutic strategy with potential for the treatment of cancer.

Isolating and targeting the real-time plasticity and malignant properties of epithelial-mesenchymal transition in cancer.

Epithelial-mesenchymal transition (EMT) is a driving force in promoting malignant cancer, including initiation, growth, and metastasis. EMT is a dynamic process that can undergo a mesenchymal-epithelial transition (MET) and partial transitions between both phenotypes, termed epithelial-mesenchymal plasticity (EMP). In cancer, the acquisition of EMP results in a spectrum of phenotypes, promoting tumor cell heterogeneity and resistance to standard of care therapy. Here we describe a real-time fluorescent dual-reporter for vimentin and E-cadherin, biomarkers of the mesenchymal and epithelial cell phenotypes, respectively. Stable dual-reporter cell lines generated from colorectal (SW620), lung (A549), and breast (MDA-MB-231) cancer demonstrate a spectrum of EMT cell phenotypes. We used the dual-reporter to isolate the quasi epithelial, epithelial/mesenchymal, and mesenchymal phenotypes. Although EMT is a dynamic process, these isolated quasi-EMT-phenotypes remain stable to spontaneous EMP in the absence of stimuli and during prolonged cell culture. However, the quasi-EMT phenotypes can readily be induced to undergo EMT or MET with growth factors or small molecules. Moreover, isolated EMT phenotypes display different tumorigenic properties and are morphologically and metabolically distinct. 3D high-content screening of ~23,000 compounds using dual-reporter mesenchymal SW620 tumor organoids identified small molecule probes that modulate EMT, and a subset of probes that effectively induced MET. The tools, probes, and models described herein provide a coherent mechanistic understanding of mesenchymal cell plasticity. Future applications utilizing this technology and probes are expected to advance our understanding of EMT and studies aimed at therapeutic strategies targeting EMT.

Advanced High-Content-Screening Applications of Clonogenicity in Cancer.

Since its first report in 1956 by Puck and Marcus, the clonogenic assay has not been completely adapted into high-content-screening (HCS) workflows despite the numerous automated systems available. Initially, clonogenic assays were used to observe the effects of radiation on cell survival, particularly with cancer cells. The clonogenic assay has since been well characterized as a measure of cancer stem cell (CSC) stemness, demonstrating that a single CSC can generate clonogenic colonies. CSCs are highly tumorigenic with an unlimited proliferation potential and capacity to generate malignant tumors. Furthermore, CSCs are also known to resist conventional chemotherapy as well as more contemporary targeted therapies alike. Therefore, given the complexity of CSCs and their clinical relevance, new methods must follow to more effectively study and characterize CSC mechanisms that allow them to proliferate and persist, and to develop drugs and other therapies that can more effectively target these populations. Herein, we present a HCS method to quantify the number and size of colonies in 2D and 3D culture models and to distinguish colonies based on fluorescent markers using an Opera Phenix high-content-screening system. In addition, we present a method to scan at low magnification and rescan at a higher magnification to capture in greater detail colonies or even single cells of interest. These methods can be adapted to numerous applications or other imaging systems to study CSC biology using high-content analysis and for high-throughput drug discovery.

First-in-Class Inhibitors of Oncogenic CHD1L with Preclinical Activity against Colorectal Cancer.

Since the discovery of CHD1L in 2008, it has emerged as an oncogene implicated in the pathology and poor prognosis of a variety of cancers, including gastrointestinal cancers. However, a mechanistic understanding of CHD1L as a driver of colorectal cancer has been limited. Until now, there have been no reported inhibitors of CHD1L, also limiting its development as a molecular target. We sought to characterize the clinicopathologic link between CHD1L and colorectal cancer, determine the mechanism(s) by which CHD1L drives malignant colorectal cancer, and discover the first inhibitors with potential for novel treatments for colorectal cancer. The clinicopathologic characteristics associated with CHD1L expression were evaluated using microarray data from 585 patients with colorectal cancer. Further analysis of microarray data indicated that CHD1L may function through the Wnt/TCF pathway. Thus, we conducted knockdown and overexpression studies with CHD1L to determine its role in Wnt/TCF-driven epithelial-to-mesenchymal transition (EMT). We performed high-throughput screening (HTS) to identify the first CHD1L inhibitors. The mechanism of action, antitumor efficacy, and drug-like properties of lead CHD1L inhibitors were determined using biochemical assays, cell models, tumor organoids, patient-derived tumor organoids, and in vivo pharmacokinetics and pharmacodynamics. Lead CHD1L inhibitors display potent in vitro antitumor activity by reversing TCF-driven EMT. The best lead CHD1L inhibitor possesses drug-like properties in pharmacokinetic/pharmacodynamic mouse models. This work validates CHD1L as a druggable target and establishes a novel therapeutic strategy for the treatment of colorectal cancer.

Drug Design Targeting T-Cell Factor-Driven Epithelial-Mesenchymal Transition as a Therapeutic Strategy for Colorectal Cancer.

Metastasis is the cause of 90% of mortality in cancer patients. For metastatic colorectal cancer (mCRC), the standard-of-care drug therapies only palliate the symptoms but are ineffective, evidenced by a low survival rate of ∼11%. T-cell factor (TCF) transcription is a major driving force in CRC, and we have characterized it to be a master regulator of epithelial-mesenchymal transition (EMT). EMT transforms relatively benign epithelial tumor cells into quasi-mesenchymal or mesenchymal cells that possess cancer stem cell properties, promoting multidrug resistance and metastasis. We have identified topoisomerase IIα (TOP2A) as a DNA-binding factor required for TCF-transcription. Herein, we describe the design, synthesis, biological evaluation, and in vitro and in vivo pharmacokinetic analysis of TOP2A ATP-competitive inhibitors that prevent TCF-transcription and modulate or reverse EMT in mCRC. Unlike TOP2A poisons, ATP-competitive inhibitors do not damage DNA, potentially limiting adverse effects. This work demonstrates a new therapeutic strategy targeting TOP2A for the treatment of mCRC and potentially other types of cancers.

An improved high yield total synthesis and cytotoxicity study of the marine alkaloid neoamphimedine: an ATP-competitive inhibitor of topoisomerase IIα and potent anticancer agent.

Recently, we characterized neoamphimedine (neo) as an ATP-competitive inhibitor of the ATPase domain of human Topoisomerase IIα. Thus far, neo is the only pyridoacridine with this mechanism of action. One limiting factor in the development of neo as a therapeutic agent has been access to sufficient amounts of material for biological testing. Although there are two reported syntheses of neo, both require 12 steps with low overall yields (≤6%). In this article, we report an improved total synthesis of neo achieved in 10 steps with a 25% overall yield. In addition, we report an expanded cytotoxicity study using a panel of human cancer cell lines, including: breast, colorectal, lung, and leukemia. Neo displays potent cytotoxicity (nM IC50 values) in all, with significant potency against colorectal cancer (lowest IC50 = 6 nM). We show that neo is cytotoxic not cytostatic, and that neo exerts cytotoxicity by inducing G2-M cell cycle arrest and apoptosis.

Design of an amide N-glycoside derivative of ß-glucogallin: a stable, potent, and specific inhibitor of aldose reductase.

ß-Glucogallin (BGG), a major component of the Emblica officinalis medicinal plant, is a potent and selective inhibitor of aldose reductase (AKR1B1). New linkages (ether/triazole/amide) were introduced via high yielding, efficient syntheses to replace the labile ester, and an original two-step (90%) preparation of BGG was developed. Inhibition of AKR1B1was assessed in vitro and using transgenic lens organ cultures, which identified the amide linked glucoside (BGA) as a stable, potent, and selective therapeutic lead toward the treatment of diabetic eye disease.

Neoamphimedine circumvents metnase-enhanced DNA topoisomerase IIα activity through ATP-competitive inhibition.

Type IIα DNA topoisomerase (TopoIIα) is among the most important clinical drug targets for the treatment of cancer. Recently, the DNA repair protein Metnase was shown to enhance TopoIIα activity and increase resistance to TopoIIα poisons. Using in vitro DNA decatenation assays we show that neoamphimedine potently inhibits TopoIIα-dependent DNA decatenation in the presence of Metnase. Cell proliferation assays demonstrate that neoamphimedine can inhibit Metnase-enhanced cell growth with an IC(50) of 0.5 µM. Additionally, we find that the apparent K(m) of TopoIIα for ATP increases linearly with higher concentrations of neoamphimedine, indicating ATP-competitive inhibition, which is substantiated by molecular modeling. These findings support the continued development of neoamphimedine as an anticancer agent, particularly in solid tumors that over-express Metnase.