Faculty Bibliography

There is an unmet clinical need for improved tissue and liquid biopsy tools for cancer detection. We investigated the proteomic profile of extracellular vesicles and particles (EVPs) in 426 human samples from tissue explants (TEs), plasma, and other bodily fluids. Among traditional exosome markers, CD9, HSPA8, ALIX, and HSP90AB1 represent pan-EVP markers, while ACTB, MSN, and RAP1B are novel pan-EVP markers. To confirm that EVPs are ideal diagnostic tools, we analyzed proteomes of TE- (n = 151) and plasma-derived (n = 120) EVPs. Comparison of TE EVPs identified proteins (e.g., VCAN, TNC, and THBS2) that distinguish tumors from normal tissues with 90% sensitivity/94% specificity. Machine-learning classification of plasma-derived EVP cargo, including immunoglobulins, revealed 95% sensitivity/90% specificity in detecting cancer. Finally, we defined a panel of tumor-type-specific EVP proteins in TEs and plasma, which can classify tumors of unknown primary origin. Thus, EVP proteins can serve as reliable biomarkers for cancer detection and determining cancer type.

Cancer patients often confront the decision of whether to continue high dose chemotherapy at the expense of cumulative toxicities. Reducing the dose of chemotherapy regimens while preserving efficacy is sorely needed to preserve the performance status of these vulnerable patients, yet has not been prioritized. Here, we introduce a dual pronged approach to modulate the microenvironment of desmoplastic pancreatic tumors and enable significant dose de-escalation of the FDA-approved chemotherapeutic nanoliposomal irinotecan (nal-IRI) without compromising tumor control. We demonstrate that light-based photodynamic priming (PDP) coupled with vitamin D3 receptor (VDR) activation within fibroblasts increases intratumoral nal-IRI accumulation and suppresses pro-tumorigenic CXCL12/CXCR7 crosstalk. Combined photodynamic and biochemical modulation of the tumor microenvironment enables a 75% dose reduction of nal-IRI while maintaining treatment efficacy, resulting in improved tolerability. Modifying the disease landscape to increase the susceptibility of cancer, via preferentially modulating fibroblasts, represents a promising and relatively underexplored strategy to enable dose de-escalation. The approach presented here, using a combination of three clinically available therapies with non-overlapping toxicities, can be rapidly translated with minimal modification to treatment workflow, and challenges the notion that significant improvements in chemotherapy efficacy can only be achieved at the expense of increased toxicity.

Pancreatic ductal adenocarcinoma (PDAC) can be divided into transcriptomic subtypes with two broad lineages referred to as classical (pancreatic) and squamous. We find that these two subtypes are driven by distinct metabolic phenotypes. Loss of genes that drive endodermal lineage specification, HNF4A and GATA6, switch metabolic profiles from classical (pancreatic) to predominantly squamous, with glycogen synthase kinase 3 beta (GSK3β) a key regulator of glycolysis. Pharmacological inhibition of GSK3β results in selective sensitivity in the squamous subtype; however, a subset of these squamous patient-derived cell lines (PDCLs) acquires rapid drug tolerance. Using chromatin accessibility maps, we demonstrate that the squamous subtype can be further classified using chromatin accessibility to predict responsiveness and tolerance to GSK3β inhibitors. Our findings demonstrate that distinct patterns of chromatin accessibility can be used to identify patient subgroups that are indistinguishable by gene expression profiles, highlighting the utility of chromatin-based biomarkers for patient selection in the treatment of PDAC.

Single-cell RNA sequencing (scRNA-seq) enables the systematic identification of cell populations in a tissue, but characterizing their spatial organization remains challenging. We combine a microarray-based spatial transcriptomics method that reveals spatial patterns of gene expression using an array of spots, each capturing the transcriptomes of multiple adjacent cells, with scRNA-Seq generated from the same sample. To annotate the precise cellular composition of distinct tissue regions, we introduce a method for multimodal intersection analysis. Applying multimodal intersection analysis to primary pancreatic tumors, we find that subpopulations of ductal cells, macrophages, dendritic cells and cancer cells have spatially restricted enrichments, as well as distinct coenrichments with other cell types. Furthermore, we identify colocalization of inflammatory fibroblasts and cancer cells expressing a stress-response gene module. Our approach for mapping the architecture of scRNA-seq-defined subpopulations can be applied to reveal the interactions inherent to complex tissues.

BACKGROUND AND AIM/OBJECTIVE:The International Cancer of the Pancreas Screening Consortium met in 2018 to update its consensus recommendations for the management of individuals with increased risk of pancreatic cancer based on family history or germline mutation status (high-risk individuals). METHODS:A modified Delphi approach was employed to reach consensus among a multidisciplinary group of experts who voted on consensus statements. Consensus was considered reached if ≥75% agreed or disagreed. RESULTS:mutation carriers with one affected first-degree relative are now considered eligible for surveillance. Experts agreed that preferred surveillance tests are endoscopic ultrasound and MRI/magnetic retrograde cholangiopancreatography, but no consensus was reached on how to alternate these modalities. Annual surveillance is recommended in the absence of concerning lesions. Main areas of disagreement included if and how surveillance should be performed for hereditary pancreatitis, and the management of indeterminate lesions. CONCLUSIONS:Pancreatic surveillance is recommended for selected high-risk individuals to detect early pancreatic cancer and its high-grade precursors, but should be performed in a research setting by multidisciplinary teams in centres with appropriate expertise. Until more evidence supporting these recommendations is available, the benefits, risks and costs of surveillance of pancreatic surveillance need additional evaluation.

Background: Patients with metastatic pancreatic cancer who have progressed on two prior lines of therapy have a poor prognosis with an overall survival in the range of 2-2.5 months. (Manax, et al. J Clin Oncol 37, 2019 suppl 4; abstr 226). There is currently no standard of care for these patients that has demonstrated improved outcomes. SM-88 (D,Lalpha- metyrosine; racemetyrosine [USAN]) is a proprietary dysfunctional tyrosine derivative and is the backbone of SM-88 used with MPS (Methoxsalen 10mg, Phenytoin 50mg and Sirolimus 0.5mg; all administered daily). SM-88 monotherapy was relatively well tolerated, with improvement in survival in select patients with heavily pretreated PDAC who achieved stable disease on therapy (HR 0.08, p = 0.02). Circulating tumor cells (CTC's) were prognostic and decreased on therapy with SM-88 potentially identifying a subgroup of PDAC that may be most likely to benefit from therapy (Noel et al. Annal Oncol V30, Suppl 4, 2019). Preliminary radiomic analysis of the largest metastases at baseline suggested the same benefits including a correlation with baseline CTCs, changes in CTCs on therapy and OS (Ocean et al, Annal Oncol, V30, Suppl 5, 2019). Here, we describe a randomized, open-label, phase 2/3 trial evaluating the efficacy of SM-88 + MPS vs physician's choice treatment as third line therapy for patients with metastatic PDAC.
Method(s): This is a multi-center Phase 3 study of patients >=18 years with metastatic PDAC that progressed after 2nd lines of chemotherapy (gemcitabine [gem] and 5-fluorouracil [5-FU] based) with an ECOG <2. Randomization will be 1:1 with 250 patients being stratified by site, ECOG, and choice of chemotherapy. SM-88 will be administered at a dose of 460mg twice daily (920 mg/day). Primary end point is Overall Survival (OS). Secondary end points include progression free survival, response rate, duration of response, pharmacokinetics, safety and CTCs

Hepatocellular Carcinoma (HCC) is one of the most lethal cancers with a high mortality and recurrence rate. Circulating tumor cell (CTC) detection offers various opportunities to advance early detection and monitoring of HCC tumors which is crucial for improving patient outcome. We developed and optimized a novel Labyrinth microfluidic device to efficiently isolate CTCs from peripheral blood of HCC patients. CTCs were identified in 88.1% of the HCC patients over different tumor stages. The CTC positivity rate was significantly higher in patients with more advanced HCC stages. In addition, 71.4% of the HCC patients demonstrated CTCs positive for cancer stem cell marker, CD44, suggesting that the major population of CTCs could possess stemness properties to facilitate tumor cell survival and dissemination. Furthermore, 55% of the patients had the presence of circulating tumor microemboli (CTM) which also correlated with advanced HCC stage, indicating the association of CTM with tumor progression. Our results show effective CTC capture from HCC patients, presenting a new method for future noninvasive screening and surveillance strategies. Importantly, the detection of CTCs with stemness markers and CTM provides unique insights into the biology of CTCs and their mechanisms influencing metastasis, recurrence and therapeutic resistance.

Despite untiring efforts to develop therapies for pancreatic ductal adenocarcinoma (PDAC), survival statistics remain dismal, necessitating distinct approaches. Photodynamic priming (PDP), which improves drug delivery and combination regimens, as well as tumor photodestruction are key attributes of photodynamic therapy (PDT), making it a distinctive clinical option for PDAC. Localized, high-payload nanomedicine-assisted delivery of photosensitizers (PSs), with molecular specificity and controlled photoactivation, thus becomes critical in order to reduce collateral toxicity during more expansive photodynamic activation procedures with curative intent. As such, targeted photoactivable lipid-based nanomedicines are an ideal candidate but have failed to provide greater than two-fold cancer cell selectivity, if at all, due to their extensive multivariant physical, optical, and chemical complexity. Here, we report (1) a systematic multivariant tuning approach to engineer (Cet, anti-EGFR mAb) photoimmunonanoconjugates (PINs), and (2) stroma-rich heterotypic PDAC in vitro and in vivo models incorporating patient-derived pancreatic cancer-associated fibroblasts (PCAFs) that recapitulate the desmoplasia observed in the clinic. These offer a comprehensive, disease-specific framework for the development of Cet-PINs. Specificity-tuning of the PINs, in terms of PS lipid anchoring, electrostatic modulation, Cet orientation, and Cet surface densities, achieved ∼16-fold binding specificities and rapid penetration of the heterotypic organoids within 1 h, thereby providing a ∼16-fold enhancement in molecular targeted NIR photodestruction. As a demonstration of their inherent amenability for multifunctionality, encapsulation of high payloads of gemcitabine hydrochloride, 5-fluorouracil, and oxaliplatin within the Cet-PINs further improved their antitumor efficacy in the heterotypic organoids. In heterotypic desmoplastic tumors, the Cet-PINs efficiently penetrated up to 470 μm away from blood vessels, and photodynamic activation resulted in substantial tumor necrosis, which was not elicited in T47D tumors (low EGFR) or when using untargeted constructs in both tumor types. Photodynamic activation of the Cet-PINs in the heterotypic desmoplastic tumors resulted in collagen photomodulation, with a 1.5-fold reduction in collagen density, suggesting that PDP may also hold potential for conquering desmoplasia. The in vivo safety profile of photodynamic activation of the Cet-PINs was also substantially improved, as compared to the untargeted constructs. While treatment using the Cet-PINs did not cause any detriment to the mice's health or to healthy proximal tissue, photodynamic activation of untargeted constructs induced severe acute cachexia and weight loss in all treated mice, with substantial peripheral skin necrosis, muscle necrosis, and bowel perforation. This study is the first report demonstrating the true value of molecular targeting for NIR-activable PINs. These constructs integrate high payload delivery, efficient photodestruction, molecular precision, and collagen photomodulation in desmoplastic PDAC tumors in a single treatment using a single construct. Such combined PIN platforms and heterocellular models open up an array of further multiplexed combination therapies to synergistically control desmoplastic tumor progression and extend PDAC patient survival.

OBJECTIVES:Pancreatic cystic lesions (PCLs) may be precancerous. Those likely to harbor high-grade dysplasia (HGD) or pancreatic cancer (PC) are targets for surgical resection. Current algorithms to predict advanced neoplasia (HGD/PC) in PCLs lack diagnostic accuracy. In pancreatic tissue and cyst fluid (CF) from PCLs, we sought to identify and validate novel methylated DNA markers (MDMs) that discriminate HGD/PC from low-grade dysplasia (LGD) or no dysplasia (ND). METHODS:From an unbiased whole-methylome discovery approach using predefined selection criteria followed by multistep validation on case (HGD or PC) and control (ND or LGD) tissues, we identified discriminant MDMs. Top candidate MDMs were then assayed by quantitative methylation-specific polymerase chain reaction on archival CF from surgically resected PCLs. RESULTS:Of 25 discriminant MDMs identified in tissue, 13 were selected for validation in 134 CF samples (21 cases [8 HGD, 13 PC], 113 controls [45 ND, 68 LGD]). A tree-based algorithm using 2 CF-MDMs (TBX15, BMP3) achieved sensitivity and specificity above 90%. Discrimination was significantly better by this CF-MDM panel than by mutant KRAS or carcinoembryonic antigen, with areas under the receiver operating characteristic curve of 0.93 (95% confidence interval: 0.86-0.99), 0.71 (0.57-0.85), and 0.72 (0.60-0.84), respectively. Cutoffs for the MDM panel applied to an independent CF validation set (31 cases, 56 controls) yielded similarly high discrimination, areas under the receiver operating characteristic curve = 0.86 (95% confidence interval: 0.77-0.94, P = 0.2). DISCUSSION:Novel MDMs discovered and validated in tissue accurately identify PCLs harboring HGD/PC. A panel of 2 MDMs assayed in CF yielded results with potential to enhance current risk prediction algorithms. Prospective studies are indicated to optimize and further evaluate CF-MDMs for clinical use.

Reactive oxygen species (ROS) are chemically active free radicals produced by partial reduction of oxygen that can activate discrete signaling pathways or disrupt redox homeostasis depending on their concentration. ROS interacts with biomolecules, including DNA, and can cause mutations that can transform normal cells into cancer cells. Furthermore, certain cancer-causing mutations trigger alterations in cellular metabolism that can increase ROS production, resulting in genomic instability, additional DNA mutations, and tumor evolution. To prevent excess ROS-mediated toxicity, cancer-causing mutations concurrently activate pathways that manage this oxidative burden. Hence, an understanding of the metabolic pathways that regulate ROS levels is imperative for devising therapies that target tumor cells. In this review, we summarize the dual role of metabolism as a generator and inhibitor of ROS in cancer and discuss current strategies to target the ROS axis.