Novel patient-derived xenograft mouse model for pancreatic acinar cell carcinoma demonstrates single agent activity of oxaliplatin

Zebrafish drug screening identifies Erlotinib as an inhibitor of Wnt/β-catenin signaling and self-renewal in T-cell acute lymphoblastic leukemia

The Wnt/β-catenin pathway's significance in cancer initiation, progression, and stem cell biology underscores its therapeutic potential. However, the clinical application of Wnt inhibitors remains limited due to challenges posed by off-target effects and complex cross-talk of Wnt signaling with other pathways. In this study, we leveraged a zebrafish model to perform a robust and rapid drug screening of 773 FDA-approved compounds to identify Wnt/β-catenin inhibitors with minimal toxicity. Utilizing zebrafish expressing a Wnt reporter, we identified several drugs that suppressed Wnt signaling without compromising zebrafish development. The efficacy of the top hit, Erlotinib, extended to human cells, where it blocked Wnt/β-catenin signaling downstream of the destruction complex. Notably, Erlotinib treatment reduced self-renewal in human T-cell Acute Lymphoblastic Leukemia cells, which rely on active β-catenin signaling for maintenance of leukemia-initiating cells. Erlotinib also reduced leukemia-initiating cell frequency and delayed disease formation in zebrafish models. This study underscores zebrafish's translational potential in drug discovery and repurposing and highlights a new use for Erlotinib as a Wnt inhibitor for cancers driven by aberrant Wnt/β-catenin signaling.

Zebrafish Drug Screening Identifies Erlotinib as an Inhibitor of Wnt/β-Catenin Signaling and Self-Renewal in T-cell Acute Lymphoblastic Leukemia

The Wnt/β-catenin pathway's significance in cancer initiation, progression, and stem cell biology underscores its therapeutic potential, yet clinical application of Wnt inhibitors remains limited due to challenges posed by off-target effects and complex crosstalk with other pathways. In this study, we leveraged the zebrafish model to perform a robust and rapid drug screening of 773 FDA-approved compounds to identify Wnt/β-catenin inhibitors with minimal toxicity. Utilizing zebrafish expressing a Wnt reporter, we identified several drugs that suppressed Wnt signaling without compromising zebrafish development. The efficacy of the top hit, Erlotinib, extended to human cells, where it blocked Wnt/β-catenin signaling downstream of the destruction complex. Notably, Erlotinib treatment reduced self-renewal in human T-cell Acute Lymphoblastic Leukemia cells, which are known to rely on active β-catenin signaling for maintenance of leukemia-initiating cells. Erlotinib also reduced leukemia-initiating cell frequency and delayed disease formation in zebrafish models. This study underscores zebrafish's translational potential in drug discovery and repurposing, and highlights a new use for Erlotinib as a Wnt inhibitor for cancers driven by aberrant Wnt/β-catenin signaling.

Highlights

Zebrafish-based drug screening offers an inexpensive and robust platform for identifying compounds with high efficacy and low toxicity in vivo . Erlotinib, an Epidermal Growth Factor Receptor (EGFR) inhibitor, emerged as a potent and promising Wnt inhibitor with effects in both zebrafish and human cell-based Wnt reporter assays.The identification of Erlotinib as a Wnt inhibitor underscores the value of repurposed drugs in developing targeted therapies to disrupt cancer stemness and improve clinical outcomes.

Derivation of pancreatic acinar cell carcinoma cell line HS-1 as a patient-derived tumor organoid

Acinar cell carcinoma (ACC) of the pancreas is a malignant tumor of the exocrine cell lineage with a poor prognosis. Due to its rare incidence and technical difficulties, few authentic human cell lines are currently available, hampering detailed investigations of ACC. Therefore, we applied the organoid culture technique to various types of specimens, such as bile, biopsy, and resected tumor, obtained from a single ACC patient. Despite the initial propagation, none of these organoids achieved long-term proliferation or tolerated cryopreservation, confirming the challenging nature of establishing ACC cell lines. Nevertheless, the biopsy-derived early passage organoid developed subcutaneous tumors in immunodeficient mice. The xenograft tumor histologically resembled the original tumor and gave rise to infinitely propagating organoids with solid features and high levels of trypsin secretion. Moreover, the organoid stained positive for carboxylic ester hydrolase, a specific ACC marker, but negative for the duct cell marker CD133 and the endocrine lineage marker synaptophysin. Hence, we concluded the derivation of a novel ACC cell line of the pure exocrine lineage, designated HS-1. Genomic analysis revealed extensive copy number alterations and mutations in EP400 in the original tumor, which were enriched in primary organoids. HS-1 displayed homozygous deletion of CDKN2A, which might underlie xenograft formation from organoids. Although resistant to standard cytotoxic agents, the cell line was highly sensitive to the proteasome inhibitor bortezomib, as revealed by an in vitro drug screen and in vivo validation. In summary, we document a novel ACC cell line, which could be useful for ACC studies in the future.

Optimizing Chemotherapy of Pancreatic Acinar Cell Carcinoma: Our Experiences and Pooled Analysis of Literature

Background:

Pancreatic acinar cell carcinoma (PACC) is rare, and its appropriate treatment remains unknown. We aim to explore the characteristics and optimal treatment of it.

Methods:

The data on clinicopathologic characteristics, molecular alteration, treatment, and survival of patients diagnosed with PACC at the Sun Yat-sen University Cancer Center from 2005 to 2020 were collected. The optimal treatment was explored by co-analyzing our results and published literatures.

Results:

Twenty-two PACC patients were enrolled. Eight of 17 non-metastatic patients received adjuvant chemotherapy. The patients receiving fluoropyrimidine-based regimen (n = 3) had a better median disease-free survival (mDFS) than those with gemcitabine-based regimen (n = 5) (unreached vs 27 months). Eight metastatic patients received first-line chemotherapy. Four patients received second-line chemotherapy. The objective response rate (ORR) of the fluoropyrimidine-based regimen was 85.7% (6/7), much better than that of the gemcitabine-based regimen (0/5). One patient who had responded to the first-line FOLFIRINOX (5-fluorouracil + oxaliplatin + leucovorin + irinotecan) regimen received olaparib as maintenance treatment for 5 months with good tolerance. Thirty-one published literatures, with a total of 86 cases, were included in the co-analysis. The ORR of the first-line fluoropyrimidine-based regimen (n = 47) was higher than that of gemcitabine-based regimen (n = 39) (59.6% vs 15.3%, P < .001). Eight of 11 patients treated with the FOLFIRINOX regimen achieved partial response (PR).

Conclusions:

For patients with metastasis, a fluorouracil-based regimen such as FOLFIRINOX may be preferred, and maintenance treatment of poly ADP-ribose polymerase (PARP) inhibitors after effective platinum-containing treatment for breast cancer susceptibility gene (BRCA) mutation patients must be assessed.

Exome Sequencing of Pancreatic Acinar Carcinoma Identified Distinctive Mutation Patterns

OBJECTIVES

Pancreatic acinar cell carcinoma (ACC) is a rare pancreatic cancer. The advancement of treatment is hampered because of the limited knowledge of its molecular mechanism.

METHODS

Whole-exome sequencing was performed on DNA extracted from 11 pure ACC surgical samples. Potential germline variants were removed on the basis of polymorphic databases, alternative allele frequency, coverage depth, and Catalogue of Somatic Mutations in Cancer (COSMIC) annotations after variant calling procedure. Mutation profiles and signatures were assessed through the Mutational Patterns package.

RESULTS

A median of 34 somatic mutations were detected (range, 19-60). Three novel recurrent small deletions were identified. Common pancreatic ductal adenocarcinoma mutations or neuroendocrine tumor mutants were not found. FAT atypical cadherin 4, mucin 5B, titin, and zinc finger homeobox 3 were consistently mutated across 4 independent ACC studies. A high contribution of COSMIC mutational signature 1 was seen in ACC, indicating deamination of 5-methylcytosine. The majority of the patients had COSMIC signatures 6, 15, or 20, relating to defective DNA mismatch repair. Six patients showed COSMIC mutational signature 10 because of the altered activity of DNA polymerase epsilon.

CONCLUSIONS

Distinct mutational signatures pathways were found in ACC and targeting them may improve clinical outcome.

An Immunocompetent Model of Pancreatic Cancer Resection and Recurrence

BACKGROUND

Even after surgical resection, most patients with localized pancreatic ductal adenocarcinoma (PDAC) succumb to disease recurrence. Current animal models do not recapitulate this pattern of disease recurrence. Our goal was to develop a clinically relevant, immunocompetent model of PDAC resection to study recurrence and evaluate therapy.

METHODS

Pancreatic cancer cells derived from tumors arising in KPC (LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx-1-Cre) mice were co-injected with stromal cells (pancreatic stellate cells) into the pancreas of immunocompetent mice to simulate the stroma-rich tumors seen in human PDAC. After allowing tumors to form, we resected these localized tumors and followed the mice for tumor recurrence. Circulating tumor cells (CTCs) were isolated, and systemic chemotherapy or immunotherapy was administered following tumor resection.

RESULTS

Tumors formed by co-injection of KPC cells and stromal cells demonstrated a dense desmoplastic reaction similar to that seen in human disease. Resection at days 15 and 21 after implantation revealed uniform tumor volumes of 92 ± 19 mm3 on day 15 and 444 ± 54 mm3 on day 21. Histology of resected tumors showed negative margins. Resembling human PDAC, mice that underwent resection showed improved median survival (58 vs 47 days) but most animals developed intra-abdominal recurrence on follow-up. Adjuvant chemotherapy (median survival 69 vs 58 days), but not immunotherapy (median survival 69 vs 65 days) tended towards improved survival as seen in human disease. Circulating tumor cells were reliably identified from mice with and without resection, suggesting utility of this model in studying tumor metastases and recurrence.

CONCLUSION

We describe an immunocompetent animal model that recapitulates human disease in morphology and recurrence patterns. We show that it can be used to evaluate therapy in clinical scenarios associated with surgical resection and may help characterize factors responsible for disease recurrence.

Noncoding RNAs in drug-resistant pancreatic cancer: A review

Pancreatic cancer is the fourth-leading cause of cancer-related deaths and is expected to be the second-leading cause of cancer-related deaths in Europe and the United States by 2030. The high fatality rate of pancreatic cancer is ascribed to untimely diagnosis, early metastasis and limited responses to both chemotherapy and radiotherapy. Although gemcitabine, 5-fluorouracil and some other drugs can profoundly improve patient prognosis, most pancreatic cancer patients eventually develop drug resistance, leading to poor clinical outcomes. The underlying mechanisms of pancreatic cancer drug resistance are complicated and inconclusive. Interestingly, accumulating evidence has demonstrated that different noncoding RNAs (ncRNAs), such as microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs), play a crucial role in pancreatic cancer resistance to chemotherapy reagents. In this paper, we systematically summarize the molecular mechanism underlying the influence of ncRNAs on the generation and development of drug resistance in pancreatic cancer and discuss the potential role of ncRNAs as prognostic markers and new therapeutic targets for pancreatic cancer.

BAP1 is a haploinsufficient tumor suppressor linking chronic pancreatitis to pancreatic cancer in mice

Chronic pancreatitis represents a risk factor for the development of pancreatic cancer. We find that heterozygous loss of histone H2A lysine 119 deubiquitinase BAP1 (BRCA1 Associated Protein-1) associates with a history of chronic pancreatitis and occurs in 25% of pancreatic ductal adenocarcinomas and 40% of acinar cell carcinomas. Deletion or heterozygous loss of Bap1 in murine pancreata causes genomic instability, tissue damage, and pancreatitis with full penetrance. Concomitant expression of Kras^G12D leads to predominantly intraductal papillary mucinous neoplasms and mucinous cystic neoplasms, while pancreatic intraepithelial neoplasias are rarely detected. These lesions progress to metastatic pancreatic cancer with high frequency. Lesions with histological features mimicking Acinar Cell Carcinomas are also observed in some tumors. Heterozygous mice also develop pancreatic cancer suggesting a haploinsufficient tumor suppressor role for BAP1. Mechanistically, BAP1 regulates genomic stability, in a catalytic independent manner, and its loss confers sensitivity to irradiation and platinum-based chemotherapy in pancreatic cancer.

Generation and application of patient-derived xenograft models in pancreatic cancer research

OBJECTIVE

Pancreatic ductal adenocarcinoma cancer (PDAC) is one of the leading causes of cancer-related death worldwide. Hence, the development of effective anti-PDAC therapies is urgently required. Patient-derived xenograft (PDX) models are useful models for developing anti-cancer therapies and screening drugs for precision medicine. This review aimed to provide an updated summary of using PDX models in PDAC.

DATA SOURCES

The author retrieved information from the PubMed database up to June 2019 using various combinations of search terms, including PDAC, pancreatic carcinoma, pancreatic cancer, patient-derived xenografts or PDX, and patient-derived tumor xenografts or PDTX.

STUDY SELECTION

Original articles and review articles relevant to the review's theme were selected.

RESULTS

PDX models are better than cell line-derived xenograft and other models. PDX models consistently demonstrate retained tumor morphology and genetic stability, are beneficial in cancer research, could enhance drug discovery and oncologic mechanism development of PDAC, allow an improved understanding of human cancer cell biology, and help guide personalized treatment.

CONCLUSIONS

In this review, we outline the status and application of PDX models in both basic and pre-clinical pancreatic cancer researches. PDX model is one of the most appropriate pre-clinical tools that can improve the prognosis of patients with pancreatic cancer in the future.

Pancreatic acinar cell carcinoma is associated with BRCA2 germline mutations: a case report and literature review

Acinar cell carcinoma (ACC) is a rare pancreatic neoplasm with dismal prognosis. Insights into the molecular basis of ACC can pave the way for the application of more effective, personalized therapies and detection of patients with hereditary predisposition.

Molecular analysis revealed a germline BRCA2 (and CHEK2) mutation in a patient with a rare pancreatic ACC with extensive intraductal growth. Somatic loss of the wild-type BRCA2 allele in the tumor indicated the causal relationship of ACC with the germline defect. A thorough literature review identified another nine ACCs associated with germline BRCA2 mutation and two ACCs associated with germline BRCA1 mutation, resulting in a prevalence of BRCA1/2 germline mutations in almost 7% of ACCs. Moreover, somatic BRCA1/2 alterations are reported in 16% of sporadic ACCs. Overall, about one fifth (22%) of all pancreatic ACCs exhibit BRCA1/2 deficiency.

This study underscores the important role of BRCA1/2 mutations in pancreatic ACC. All ACC patients should undergo genetic testing for BRCA1/2 mutations to identify carriers of pathogenic variants. This will allow to select patients that can benefit from targeted therapies directed against BRCA1/2-deficient tumors and is also crucial as a referral to genetic screening for the relatives of affected individuals carrying germline BRCA1/2 alterations.

Abbreviations: ACC: acinar cell carcinoma; HBOC: Hereditary Breast and Ovarian Cancer; LOH: loss of heterozygosity; PARP: poly (ADP-ribose) polymerase; PDAC: pancreatic ductal adenocarcinoma; PP: pancreatic panniculitis; SD: standard deviation; WES: whole-exome sequencing.

Pancreatic acinar cell carcinoma presenting with panniculitis, successfully treated with FOLFIRINOX: A case report

Pancreatic acinar cell carcinoma (PACC) is a rare tumor of the exocrine pancreas, representing only 1% of all pancreatic malignancies. A 50-year-old man presented with edema of the thumb joints bilaterally, followed by an appearance of masses in the bilateral lower extremities and fever (38°C). The masses were diagnosed as panniculitis by skin biopsy, and multiple intraperitoneal masses were incidentally detected on pelvic magnetic resonance imaging performed to investigate the leg abnormalities. The patient was referred to the Kyushu University Hospital for further investigation, and fluorodeoxyglucose-positron emission tomography/computed tomography (CT) revealed high-uptake tumors in the pancreatic tail, in the periphery of the liver, and in the pelvis. Laboratory examinations revealed high serum concentrations of pancreatic exocrine enzymes, such as lipase, trypsin, elastase 1 and pancreatic phospholipase A2. Histological examination of a bioptic specimen obtained from a hepatic lesion revealed proliferation of atypical cells arranged in a tubular or glandular pattern. Immunohistochemical staining revealed that the atypical cells were positive for cytokeratin (CK)7, CK19 and lipase, but negative for CK20 and thyroid transcription factor-1, leading to a final diagnosis of acinar cell carcinoma of the pancreatic tail (T4bN0M1, stage IV according to the 7th edition of the TNM Classification of Malignant Tumors). Combined chemotherapy with oxaliplatin, irinotecan and fluorouracil (FOLFIRINOX) was administered and fever was soon alleviated. The serum levels of lipase also declined and panniculitis completely resolved. As of the start of the 8th course of chemotherapy, the levels of the pancreatic exocrine enzymes were within normal ranges and CT revealed partial response. Therefore, the severe lipase hypersecretion syndrome was well controlled by the FOLFIRINOX regimen and shrinkage of the mass was also achieved. Thus, the FOLFIRINOX regimen may represent an effective treatment option for advanced PACC.

Acinar cell carcinoma of the pancreas: a rare disease with different diagnostic and therapeutic implications than ductal adenocarcinoma

PURPOSE

Acinar cell carcinoma (ACC) of the pancreas is a very rare cancer, constituting 1 % of all malignant non-endocrine pancreatic tumors. Only very limited data exist to guide treatment in patients with advanced ACC.

METHODS

Between 2000 and 2015, 15 patients with ACC were diagnosed and/or treated at our high-volume comprehensive cancer center. Medical records and correlating serum levels of the potential serum tumor markers CA 19-9, CEA and lipase were analyzed retrospectively.

RESULTS

A substantial antitumor activity was observed for treatment regimens containing 5-FU and oxaliplatin with partial responses or prolonged disease stabilizations (>12 months) observed in 6 out of 7 patients (86 %). Activity was also observed for single-agent 5-FU and its oral prodrugs. Serum lipase levels were elevated in 7 of 12 patients with advanced disease (58 %), whereas CEA and CA 19-9 seemed to be of minor importance for ACC (elevated pre-treatment levels in 4/12 and 3/12 cases, respectively). In selected patients, repeated serum lipase measurements were available and accurately predicted response to chemotherapy and relapse after surgery.

CONCLUSIONS

5-FU- and oxaliplatin-containing regimens are active in advanced ACC. Lipase kinetics may be a useful novel tool to monitor the course of disease as well as treatment effects in ACC.