Toward the goal of personalized therapy in pancreatic cancer by targeting the molecular phenotype

Special Issue: Cancer Biomarkers and Targets in Digestive Organs

The identification and development of cancer biomarkers and targets have greatly accelerated progress towards precision medicine in oncology. [...].

Frontiers in Gastrointestinal Oncology: Advances in Multi-Disciplinary Patient Care

Cancers of the digestive system remain highly lethal; therefore, the care of patients with malignant diseases of the digestive tract requires the expertise of providers from multiple health disciplines. Progress has been made to advance the understanding of epidemiology and genetics, diagnostic and screening evaluation, treatment modalities, and supportive care for patients with gastrointestinal cancers. At the Multi-Disciplinary Patient Care in Gastrointestinal Oncology conference at the Hershey Country Club in Hershey, Pennsylvania on 29 September 2017, the faculty members of the Penn State Health Milton S. Hershey Medical Center presented a variety of topics that focused on this oncological specialty. In this continuing medical education-certified conference, updates on the population sciences including health disparities and resistance training were presented. Progress made in various diagnostic evaluation and screening procedures was outlined. New developments in therapeutic modalities in surgical, radiation, and medical oncology were discussed. Cancer genetic testing and counseling and the supportive roles of music and arts in health and cancer were demonstrated. In summary, this disease-focused medical conference highlighted the new frontiers in gastrointestinal oncology, and showcase the multi-disciplinary care provided at the Penn State Cancer Institute.

Update in Systemic and Targeted Therapies in Gastrointestinal Oncology

Progress has been made in the treatment of gastrointestinal cancers through advances in systemic therapies, surgical interventions, and radiation therapy. At the Multi-Disciplinary Patient Care in Gastrointestinal Oncology conference, the faculty members of the Penn State Health Milton S. Hershey Medical Center presented a variety of topics that focused on this sub-specialty. This conference paper highlights the new development in systemic treatment of various malignant diseases in the digestive system. Results of the recent clinical trials that investigated the clinical efficacy of pegylated hyaluronidase, napabucasin, and L-asparaginase in pancreatic carcinoma are presented. The use of peri-operative chemotherapy comprised of 5-fluorouracil or capecitabine, leucovorin, oxaliplatin, and docetaxel (FLOT), and immunotherapy including pembrolizumab, nivolumab, and ipilimumab in gastroesophageal carcinoma are discussed. Data from clinical trials that investigated the targeted therapeutics including nivolumab, ramucirumab, lenvatinib, and BLU-554 are reported. The role of adjuvant capecitabine in resected biliary tract carcinoma (BTC) and nab-paclitaxel in combination with gemcitabine and cisplatin in advanced BTC are presented. In colorectal carcinoma, the efficacy of nivolumab, adjuvant FOLFOX or CAPOX, irinotecan/cetuximab/vemurafenib, and trifluridine/tipiracil/bevacizumab, is examined. In summary, some of the above systemic therapies have become or are expected to become new standard of care, while the others demonstrate the potential of becoming new treatment options.

Focal adhesion kinase inhibitor PF573228 and death receptor 5 agonist lexatumumab synergistically induce apoptosis in pancreatic carcinoma

Pancreatic cancer has one of the lowest survival rates of all cancers. The mechanism underlying chemo-resistance of pancreatic cancer is not well understood. Our previous article reported that small molecule YM155 induced apoptosis in pancreatic cancer cells via activation of death receptor 5. In this study, we aim to continuously address death receptor 5-mediated apoptosis in chemo-resistant pancreatic carcinoma. We found that in comparison to paired pancreatic cancer tissues and adjacent normal tissues, five of the six cancer tissues had downregulated death receptor 5 and upregulated Bcl-xL. Mono treatment with lexatumumab was not sufficient to induce apoptosis in pancreatic cancer cells, whereas focal adhesion kinase inhibitor PF573228 significantly sensitized lexatumumab-induced apoptosis. Western blotting analysis revealed that lexatumumab and PF573228 combination treatment increased death receptor 5 but decreased Bcl-xL expression. Interestingly, pre-treatment with Bcl-xL inhibitor ABT263 reversed the insensitivity of panc-1 cells to lexatumumab or PF573228-induced apoptosis. Specific small interfering RNA-mediated gene silencing of Bcl-xL effectively sensitized pancreatic cancer cells to lexatumumab or PF573228-induced apoptosis. Furthermore, lexatumumab and PF573228 combination was shown to exhibit significant xenograft pancreatic tumor growth inhibition in SCID mice. Our data provide fundamental evidence to support the notion that lexatumumab and PF573228 co-treatment could be a potentially effective regime for patients with pancreatic cancer.

Aberrant over-expression of TRPM7 ion channels in pancreatic cancer: required for cancer cell invasion and implicated in tumor growth and metastasis

Our previous studies in zebrafish development have led to identification of the novel roles of the transient receptor potential melastatin-subfamily member 7 (TRPM7) ion channels in human pancreatic cancer. However, the biological significance of TRPM7 channels in pancreatic neoplasms was mostly unexplored. In this study, we determined the expression levels of TRPM7 in pancreatic tissue microarrays and correlated these measurements in pancreatic adenocarcinoma with the clinicopathological features. We also investigated the role of TRPM7 channels in pancreatic cancer cell invasion using the Matrigel(TM)-coated transwell assay. In normal pancreas, TRPM7 is expressed at a discernable level in the ductal cells and centroacinar cells and at a relatively high level in the islet endocrine cells. In chronic pancreatitis, pre-malignant tissues, and malignant neoplasms, there is variable expression of TRPM7. In the majority of pancreatic adenocarcinoma specimens examined, TRPM7 is expressed at either moderate-level or high-level. Anti-TRPM7 immunoreactivity in pancreatic adenocarcinoma significantly correlates with the size and stages of tumors. In human pancreatic adenocarcinoma cells in which TRPM7 is highly expressed, short hairpin RNA-mediated suppression of TRPM7 impairs cell invasion. The results demonstrate that TRPM7 channels are over-expressed in a proportion of the pre-malignant lesions and malignant tumors of the pancreas, and they are necessary for invasion by pancreatic cancer cells. We propose that TRPM7 channels play important roles in development and progression of pancreatic neoplasm, and they may be explored as clinical biomarkers and targets for its prevention and treatment.

Select biomarkers for tumors of the gastrointestinal tract: present and future

CONTEXT

Advances in molecular biomarkers of the gastrointestinal tract have contributed to a decline in the incidence of and mortality from diseases of the gastrointestinal tract. The discovery and clinical validation of new biomarkers are important to personalized cancer therapy, and numerous clinical trials are currently ongoing to help identify individualized therapy affecting these biomarkers and molecular mechanisms they represent. Distinct molecular pathways leading to cancers of the colorectum, esophagus, stomach, small bowel, and pancreas have been identified. Using biomarkers in these pathways to direct patient care, including selection of proper molecular testing for identification of actionable mutations and reporting the results of these biomarkers to guide clinicians and genetic counselors, is paramount.

OBJECTIVE

To examine and review select clinically actionable biomarkers of the colon, esophagus, stomach, small bowel, and pancreas, including present and future biomarkers with relevant clinical trials.

DATA SOURCES

Extensive literature review and practical and consultation experience of the authors.

CONCLUSIONS

Although numerous biomarkers have been identified and are currently guiding patient therapy, few have shown evidence of clinical utility in the management of patients with gastrointestinal cancers. Inconsistent results and discordant proposed algorithms for testing were identified throughout the literature; however, the potential for biomarkers to improve outcomes for patients with gastrointestinal cancer remains high. Continued advances through high-quality studies are needed.

Aberrantly Over-Expressed TRPM8 Channels in Pancreatic Adenocarcinoma: Correlation with Tumor Size/Stage and Requirement for Cancer Cells Invasion

The transient receptor potential melastatin-subfamily member 8 (TRPM8) channels control Ca²⁺ homeostasis. Recent studies indicate that TRPM8 channels are aberrantly expressed and required for cellular proliferation in pancreatic adenocarcinoma. However, the functional significance of TRPM8 in pancreatic tissues is mostly unknown. The objectives of this study are to examine the expression of TRPM8 in various histopathological types of pancreatic tissues, determine its clinical significance in pancreatic adenocarcinoma, and investigate its functional role in cancer cells invasion. We present evidence that, in normal pancreatic tissues, anti-TRPM8 immunoreactivity is detected in the centroacinar cells and the islet endocrine cells. In pre-malignant pancreatic tissues and malignant neoplasms, TRPM8 is aberrantly expressed to variable extents. In the majority of pancreatic adenocarcinoma, TRPM8 is expressed at moderate or high levels, and anti-TRPM8 immunoreactivity positively correlates with the primary tumor size and stage. In the pancreatic adenocarcinoma cell lines that express relatively high levels of TRPM8, short hairpin RNA-mediated interference of TRPM8 expression impaired their ability of invasion. These data suggest that aberrantly expressed TRPM8 channels play contributory roles in pancreatic tumor growth and metastasis, and support exploration of TRPM8 as a biomarker and target of pancreatic adenocarcinoma.

[Will molecular diagnostics become established in pancreatic pathology?]

Genetic alterations of solid and cystic tumors of the pancreas have been increasingly more characterized over the last few years. Pancreatic ductal adenocarcinoma (PDAC) carries numerous point mutations and, to a lesser extent, deletions and amplifications of genes that are associated with at least 13 tumor relevant signalling pathways and processes. Besides the four common driver mutations in the KRAS, p53, CDKN2a and SMAD4 genes there are a number of low frequency driver mutations. The classification of PDAC subtypes has benefited from recent analyses of transcriptional profiles that revealed a classical KRAS driven and a KRAS independent quasi-mesenchymal subtype. The analyses of mRNA and miRNA expression profiles of fine needle aspirates serve as a basis for reliable preoperative diagnosis of pancreatic masses.The four most common cystic pancreatic tumors bear tumor-specific genetic alterations, such as GNAS mutations in intraductal papillary mucinous neoplasms, β-catenin mutations in solid pseudopapillary neoplasms and VHL mutations or loss of heterozygosity in serous cystadenoma. Recovery of DNA from aspirates of cyst fluids enables an improved preoperative management of cystic pancreatic tumors by mutational analysis. In addition to the analysis of DNA there are promising approaches in distinguishing benign and premalignant/malignant cystic tumors by evaluating miRNA profiles.In recent years much progress has been made in molecular genetic characterization and preoperative evaluation of pancreatic tumors. Hopefully these results will contribute to prognostic and therapeutic stratification of PDAC and to a reliable preoperative diagnostics of benign cystic pancreatic tumors in the future.

Translating discovery in zebrafish pancreatic development to human pancreatic cancer: biomarkers, targets, pathogenesis, and therapeutics

Abstract Experimental studies in the zebrafish have greatly facilitated understanding of genetic regulation of the early developmental events in the pancreas. Various approaches using forward and reverse genetics, chemical genetics, and transgenesis in zebrafish have demonstrated generally conserved regulatory roles of mammalian genes and discovered novel genetic pathways in exocrine pancreatic development. Accumulating evidence has supported the use of zebrafish as a model of human malignant diseases, including pancreatic cancer. Studies have shown that the genetic regulators of exocrine pancreatic development in zebrafish can be translated into potential clinical biomarkers and therapeutic targets in human pancreatic adenocarcinoma. Transgenic zebrafish expressing oncogenic K-ras and zebrafish tumor xenograft model have emerged as valuable tools for dissecting the pathogenetic mechanisms of pancreatic cancer and for drug discovery and toxicology. Future analysis of the pancreas in zebrafish will continue to advance understanding of the genetic regulation and biological mechanisms during organogenesis. Results of those studies are expected to provide new insights into how aberrant developmental pathways contribute to formation and growth of pancreatic neoplasia, and hopefully generate valid biomarkers and targets as well as effective and safe therapeutics in pancreatic cancer.