Faculty Bibliography

The ineffectiveness of chemotherapy in patients with pancreatic cancer highlights a critical unmet need in pancreatic cancer therapy. Two commonly mutated genes in pancreatic cancer, KRAS and CDKN2A, have an incidence exceeding 90%, supporting investigation of dual targeting of MEK and CDK4/6 as a potential therapeutic strategy for this patient population. An in vitro proliferation synergy screen was conducted to evaluate response of a panel of high passage and patient-derived pancreatic cancer models to the combination of trametinib and palbociclib to inhibit MEK and CDK4/6, respectively. Two adenosquamous carcinoma models, L3.6pl and UM59, stood out for their high synergy response. In vivo studies confirmed that this combination treatment approach was highly effective in subcutaneously implanted L3.6pl and UM59 tumor-bearing animals. Both models were refractory to single agent treatment. Reverse phase protein array analysis of L3.6pl tumors excised from treated animals revealed strong down regulation of cyclooxygenase-2 (COX-2) expression in response to combination treatment. Expression of COX-2 under a CMV-driven promoter and shRNA knockdown of COX-2 both led to resistance to combination treatment. Our findings suggest that COX-2 may be involved in the improved therapeutic outcome seen in some pancreatic tumors that fail to respond to MEK or CDK4/6 inhibitors alone but respond favorably to their combination.

PURPOSE:The treatment of cancer is complex, which can overwhelm patients and lead to poor comprehension and recall of the specifics of the cancer stage, prognosis, and treatment plan. We hypothesized that an oncologist can feasibly record and deliver a custom video summary of the consultation that covers the diagnosis, recommended testing, treatment plan, and follow-up in < 5 minutes. The video summary allows the patient to review and share the most important part of a cancer consultation with family and caregivers. METHODS:At the conclusion of the office visit, oncologists recorded the most important points of the consultation, including the diagnosis and management plan as a short video summary. Patients were then e-mailed a link to a secure Website to view and share the video. Patients and invited guests were asked to respond to an optional survey of 15 multiple-choice and four open-ended questions after viewing the video online. RESULTS:Three physicians recorded and sent 58 video visit summaries to patients seen in multidisciplinary GI cancer clinics. Forty-one patients logged into the secure site, and 38 viewed their video. Fourteen patients shared their video and invited a total of 46 visitors, of whom 36 viewed the videos. Twenty-six patients completed the survey, with an average overall video satisfaction score of 9 on a scale of 1 to 10, with 10 being most positive. CONCLUSION:Video visit summaries provide a personalized education tool that patients and caregivers find highly useful while navigating complex cancer care. We are exploring the incorporation of video visit summaries into the electronic medical record to enhance patient and caregiver understanding of their specific disease and treatment.

Cancer heterogeneity is a notorious hallmark of this disease, and it is desirable to tailor effective treatments for each individual patient. Drug combinations have been widely accepted in cancer treatment for better therapeutic efficacy as compared to a single compound. However, experimental complexity and cost grow exponentially with more target compounds under investigation. The primary challenge remains to efficiently perform a large-scale drug combination screening using a small number of patient primary samples for testing. Here, a scalable, easy-to-use, high-throughput drug combination screening scheme is reported, which has the potential of screening all possible pairwise drug combinations for arbitrary number of drugs with multiple logarithmic mixing ratios. A "Christmas tree mixer" structure is introduced to generate a logarithmic concentration mixing ratio between drug pairs, providing a large drug concentration range for screening. A three-layer structure design and special inlets arrangement facilitate simple drug loading process. As a proof of concept, an 8-drug combination chip is implemented, which is capable of screening 172 different treatment conditions over 1032 3D cancer spheroids on a single chip. Using both cancer cell lines and patient-derived cancer cells, effective drug combination screening is demonstrated for precision medicine.

Adaptive resistance to MEK inhibitors (MEK-Is) typically occurs via induction of genes for different receptor tyrosine kinases (RTKs) and/or their ligands, even in tumors of the same histotype, making combination strategies challenging. SHP2 (PTPN11) is required for RAS/ERK pathway activation by most RTKs, and might provide a common resistance node. We found that combining the SHP2 inhibitor SHP099 with a MEK-I inhibited the proliferation of multiple cancer cell lines in vitro. PTPN11 knockdown/MEK-I treatment had similar effects, while expressing SHP099 binding-defective PTPN11 mutants conferred resistance, demonstrating that SHP099 is on-target. SHP099/trametinib was highly efficacious in xenograft and/or genetically engineered models of KRAS-mutant pancreas, lung, and ovarian cancer and in wild type RAS-expressing triple negative breast cancer. SHP099 inhibited activation of KRAS mutants with residual GTPase activity, impeded SOS/RAS/MEK/ERK1/2 reactivation in response to MEK-Is and blocked ERK1/2-dependent transcriptional programs. We conclude that SHP099/MEK-I combinations could have therapeutic utility in multiple malignancies.

Bladder cancer is a significant health problem. It is estimated that more than 16,000 people will die this year in the United States from bladder cancer. While 75% of bladder cancers are non-invasive and unlikely to metastasize, about 25% progress to an invasive growth pattern. Up to half of the patients with invasive cancers will develop lethal metastatic relapse. Thus, understanding the mechanism of invasive progression in bladder cancer is crucial to predict patient outcomes and prevent lethal metastases. In this article, we present a three-dimensional cancer invasion model which allows incorporation of tumor cells and stromal components to mimic in vivo conditions occurring in the bladder tumor microenvironment. This model provides the opportunity to observe the invasive process in real time using time-lapse imaging, interrogate the molecular pathways involved using confocal immunofluorescent imaging and screen compounds with the potential to block invasion. While this protocol focuses on bladder cancer, it is likely that similar methods could be used to examine invasion and motility in other tumor types as well.

The biological properties of pancreatic cancer stem cells (PCSCs) remain incompletely defined and the central regulators are unknown. By bioinformatic analysis of a human PCSC-enriched gene signature, we identified the transcription factor HNF1A as a putative central regulator of PCSC function. Levels of HNF1A and its target genes were found to be elevated in PCSCs and tumorspheres, and depletion of HNF1A resulted in growth inhibition, apoptosis, impaired tumorsphere formation, decreased PCSC marker expression, and downregulation of POU5F1/OCT4 expression. Conversely, HNF1A overexpression increased PCSC marker expression and tumorsphere formation in pancreatic cancer cells and drove pancreatic ductal adenocarcinoma (PDA) cell growth. Importantly, depletion of HNF1A in xenografts impaired tumor growth and depleted PCSC marker-positive cells in vivo. Finally, we established an HNF1A-dependent gene signature in PDA cells that significantly correlated with reduced survivability in patients. These findings identify HNF1A as a central transcriptional regulator of PCSC properties and novel oncogene in PDA.

We investigated whether intrapancreatic coagulation, with deposition of the fibrinogen-γ dimer (Fib-γD) and hypoxia, affect the severity of acute pancreatitis (AP) in mice. Pancreata of mice with AP induced by administration of cerulein or by L-arginine, or from patients with pancreatitis, had increased deposition of Fib-γD compared with control pancreata. Heparin administration protected mice from cerulein-induced AP and prevented Fib-γD formation. Cerulein administration resulted in activation and stabilization of hypoxia-inducible factor-1α (HIF1α) in pancreata of oxygen-dependent degradation domain-luciferase HIF1α reporter mice. Cerulein also led to induction of genes regulated by HIF1α, including Vegfa and Ero1a, before evidence of Fib-γD deposition or histologic features of AP. Expression of tissue factor, which is regulated by vascular endothelial growth factor, also increased following cerulein administration. Mice with acinar cell-specific disruption of Hif1a (Hif1a^Ac-/-) developed spontaneous endoplasmic reticulum stress and less severe AP, but did not accumulate Fib-γD following administration of cerulein. Feeding mice increased pancreatic expression of HIF1α, indicating a physiologic role in the exocrine pancreas. Therefore, HIF1α has bifunctional roles, in exocrine pancreas homeostasis and progression of AP that is promoted by intrapancreatic coagulation.

In recent years, as the high burden of surgical disease and poor access to surgical care in low- and middle-income countries have gained recognition as major public health problems, interest in global health has surged among surgical trainees and faculty. Traditionally, clinical volunteerism was at the forefront of the high-income country response to the significant burden of surgical disease in low- and middle-income countries. However, sustainable strategies for providing surgical care in low- and middle-income countries increasingly depend on bilateral clinical, research, and education collaborations to ensure effective resource allocation and contextual relevance. Academic global surgery creates avenues for interested surgeons to combine scholarship and education with their clinical global surgery passions through incorporation of basic/translational, education, clinical outcomes, or health services research with global surgery. Training in global health, either within residency or through advanced degrees, can provide the necessary skills to develop and sustain such initiatives. We further propose that creating cross-continental, bidirectional collaborations can maximize funding opportunities. Academic institutions are uniquely positioned to lead longitudinal and, importantly, sustainable global surgery efforts. However, for the individual global surgeon, the career path forward may be unclear. This paper reviews the development of academic global surgery, delineates the framework and factors critical to training global surgeons, and proposes models for establishing an academic career in this field. Overall, with determination, the academic global surgeon will not only carve out a niche of expertise but will define this critical field for future generations.

Hepatocyte nuclear factor 1A (HNF1A) is a transcription factor essential to normal pancreas and liver development and homeostasis. HNF1A has been shown to be upregulated in pancreatic cancer stem cells (CSC), a proposed key driver of pancreatic ductal adenocarcinoma (PDAC), relative to other pancreatic cancer cells. A CSC gene signature consisting of 50 upregulated genes, including HNF1A, was previously identified by a microarray. This signature predicts worse survival compared to HNF1A expression alone. This research aims to establish an HNF1A-dependent gene signature that could potentially be used as a biomarker for pancreatic cancer. Using quantitative reverse transcriptase PCR, multiple CSC signature genes were shown to respond to HNF1A knockdown and overexpression. Responsive genes varied across cell lines, suggesting a complex pathway significantly affected by HNF1A transcriptional control

Usp9x has emerged as a potential therapeutic target in some hematologic malignancies and a broad range of solid tumors including brain, breast, and prostate. To examine Usp9x tumorigenicity and consequence of Usp9x inhibition in human pancreatic tumor models, we carried out gain- and loss-of-function studies using established human pancreatic tumor cell lines (PANC1 and MIAPACA2) and four spontaneously immortalized human pancreatic patient-derived tumor (PDX) cell lines. The effect of Usp9x activity inhibition by small molecule deubiquitinase inhibitor G9 was assessed in 2D and 3D culture, and its efficacy was tested in human tumor xenografts. Overexpression of Usp9x increased 3D growth and invasion in PANC1 cells and up-regulated the expression of known Usp9x substrates Mcl-1 and ITCH. Usp9x inhibition by shRNA-knockdown or by G9 treatment reduced 3D colony formation in PANC1 and PDX cell lines, induced rapid apoptosis in MIAPACA2 cells, and associated with reduced Mcl-1 and ITCH protein levels. Although G9 treatment reduced human MIAPACA2 tumor burden in vivo, in mouse pancreatic cancer cell lines established from constitutive (8041) and doxycycline-inducible (4668) KrasG12D/Tp53R172H mouse pancreatic tumors, Usp9x inhibition increased and sustained the 3D colony growth and showed no significant effect on tumor growth in 8041-xenografts. Thus, Usp9x inhibition may be therapeutically active in human PDAC, but this activity was not predicted from studies of genetically engineered mouse pancreatic tumor models.