Project Abstract:
Hypothesis & Specific Aims:
Hypothesis:
We hypothesize that the tumor microenvironment is heavily involved in dictating pancreatic cancer metastasis and chemoresistance. Here, we use mass spectrometry imaging to probe untargeted sptial metabolic changes in regions of metastasis and chemoresistant regions of pancreatic cancer. Additionally, we develop analytical methods to
Aim 1: Combining Mass Spectrometric Imaging and Second Harmonic Generation Imaging. Here, flash frozen human pancreas cancer biopsies are analyzed from m/z 50-1000 to characterize the distribution of hundreds of metabolites in the tissues. Following analysis, Second Harmonic Generation is used to analyze the collagen fiber alignment in these same tissues. Analyses are overlaid spatially and region of interest discriminate analysis is used to reveal metabolites that can statistically distinguish aligned and unaligned regions of pancreatic cancer tumors. Collagen alignment in pancreatic cancer is a negative prognostic of survival. MSI enable us to understanding molecular signatures in these aligned regions that may be contributing to decrease survival rates.
Aim 2: Combining Mass Spectrometric Imaging and Optical Metabolic Imaging. Optical Metabolic Imaging measures the dynamic intrinsic fluorescence of metabolites NADH and FAD, which can be used to calculate a readout of tumor drug response using pancreatic cancer organoid systems. MSI is coupled with optical metabolic imaging to provide a readout of the drug and drug metabolites distribution within the organoid, as well as an untargeted analysis of metabolism biomarkers. This can reveal a more comprehensive analysis of the biological response of combination chemotherapy and can confirm the optical metabolic readouts of drug efficacy.
Aim 3: Expanding Mass Spectrometry Imaging to Formalin Fixed Paraffin Embedded Samples Histopathological examination of tissues is used to stratify patient specimens and provide a diagnosis to help the patient get the best standard of care. While pathology relies heavily on visual inspection of tissues, MSI can provide an unbiased, analytic analysis of biomarkers in the tissue to supplement a pathologist’s diagnosis. Here, we compare MSI metabolite analysis between formalin fixed paraffin embedded and flash frozen pancreatic cancer spheroids. This analysis will allow us to understand what metabolite biomarker distributions can be conserved through the fixation process. Following this analysis, MSI can be expanded to analyze conserved metabolites in large tissue banks and tissue microarrays for prognostic and diagnostic biomarkers analysis in large patient samples sets.
Pancreatic Cancer Significance Section:
Pancreatic ductal adenocarcinoma (PDAC), the most common type of pancreatic cancer, is a death sentence. PDAC remains one of the hardest-to-treat cancers because most patients diagnosed at a late, metastatic stage, with only 20% of patients eligible for surgical resection. Additionally, treatment options are often ineffective. Despite aggressive treatment regiments and persistent research efforts, there has been little improvement in the 5-year PDAC patient survival in the last 50 years. Currently, even the best treatment options only prolong life by 6 to 12 weeks. PDAC lethality is largely attributed to early and aggressive metastasis, late diagnosis, and resistance to current therapeutic regimens. PDAC chemoresistance may be a result of the influence of the tumor microenvironment and increased extracellular matrix (ECM) deposition characteristic of PDAC histology. Additionally although some genetic and environmental factors have been implicated in PDAC carcinogenesis, the exact pathological mechanisms underlying progression to metastasis remain unclear. It is believed in the tumor micronevironment, consisiting of pancreatic stellate cells and cells involved in immunosuprresion, can makeup to 90% of the tumor volume. This excess ECM provides a single experimentshell withoutof protection around the tumor and causes vasculature collapse, preventing drug penetration. New alternative therapies targeting the tumor microenvironment are urgently being developed to improve pancreatic cancer outcomes.
Thevitro combinationmethods ofto informationevaluate efficacy gainedof from stromal targeting therapies. Since the extremely dismal prognosis of PDAC is largely attributed to frequent local invasiveness and metastasis, it is essential to 1) catalog stromal changes associated with poor prognosis and cancer cell dissemination and 2) establish predictive experimental models that recreate key stromal changes to study biological mechanisms and ultimately assess novel drugs intended to block metastasis for improved patient care.
Nonetheless, increased complexity and heterogeneity suggests the need for personalized medicine to make therapeutic advances in PDAC and likely other cancers. With our exponentially increasing understanding of the molecular basis of PDAC and its microenvironment, this is an exciting time as we shift our focus to the tumor–stroma relationship to design new therapies for a currently deadly disease.\cite{26747091}