Marina Macchini

Dclk1 Defines Quiescent Pancreatic Progenitors that Promote Injury-Induced Regeneration and Tumorigenesis

The existence of adult pancreatic progenitor cells has been debated. While some favor the concept of facultative progenitors involved in homeostasis and repair, neither a location nor markers for such cells have been defined. Using genetic lineage tracing, we show that Doublecortin-like kinase-1 (Dclk1) labels a rare population of long-lived, quiescent pancreatic cells. In vitro, Dclk1+ cells proliferate readily and sustain pancreatic organoid growth. In vivo, Dclk1+ cells are necessary for pancreatic regeneration following injury and chronic inflammation. Accordingly, their loss has detrimental effects after cerulein-induced pancreatitis. Expression of mutant Kras in Dclk1+ cells does not affect their quiescence or longevity. However, experimental pancreatitis converts Kras mutant Dclk1+ cells into potent cancer-initiating cells. As a potential effector of Kras, Dclk1 contributes functionally to the pathogenesis of pancreatic cancer. Taken together, these observations indicate that Dclk1 marks quiescent pancreatic progenitors that are candidates for the origin of pancreatic cancer.

State of the art biological therapies in pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies with a five-year survival rate of approximately 5%. Several target agents have been tested in PDAC, but almost all have failed to demonstrate efficacy in late phase clinical trials, despite the better understanding of PDAC molecular biology generated by large cancer sequencing initiatives in the past decade. Eroltinib (a small-molecule tyrosine-kinase inhibitor of epidermal growth factor receptor) plus gemcitabine is the only schedule with a biological agent approved for advanced pancreatic cancer, but it has resulted in a very modest survival benefit in unselected patients. In our work, we report a summary of the main clinical trials (closed and ongoing) that refer to biological therapy evaluation in pancreatic cancer treatment.

Venous Thromboembolism and Port-Related Thrombosis in Metastatic Colorectal Cancer Patients: A Monocenter Experience

Venous thromboembolism (VTE) may occur during the natural history of neoplastic disease and is a common cause of mortality and morbidity in cancer patients. Major risk factors for VTE in cancer patients include surgery, immobilization, hospitalization, and the administration of granulopoietic and/or erythropoietic (stimulatory) agents. Chemotherapy is a supplementary independent risk factor for VTE and the use of central venous catheters (CVC) in clinical practice has increased the risk of thromboembolic events. We conducted a retrospective study to evaluate CVC-related thrombosis and the VTE rate in 145 consecutive metastatic colorectal cancer patients. We observed only 2 cases of symptomatic CVC- related thrombotic events (1.38%) and 10 cases of thromboembolic events (6.9%) in our series. Only surgery for metastases was found to be significantly related to the development of VTE, with an incidence of 16.1% vs. 4.4 in patients who did not undergo surgery (p = 0.037). In addition, a history of VTE seems to be a supplementary risk factor for CVC-related thrombosis (p = 0.055).

Characterization of pancreatic ductal adenocarcinoma using whole transcriptome sequencing and copy number analysis by single-nucleotide polymorphism array

The aim of the current study was to implement whole transcriptome massively parallel sequencing (RNASeq) and copy number analysis to investigate the molecular biology of pancreatic ductal adenocarcinoma (PDAC). Samples from 16 patients with PDAC were collected by ultrasound‑guided biopsy or from surgical specimens for DNA and RNA extraction. All samples were analyzed by RNASeq performed at 75x2 base pairs on a HiScanSQ Illumina platform. Single‑nucleotide variants (SNVs) were detected with SNVMix and filtered on dbSNP, 1000 Genomes and Cosmic. Non‑synonymous SNVs were analyzed with SNPs&GO and PROVEAN. A total of 13 samples were analyzed by high resolution copy number analysis on an Affymetrix SNP array 6.0. RNAseq resulted in an average of 264 coding non‑synonymous novel SNVs (ranging from 146‑374) and 16 novel insertions or deletions (In/Dels) (ranging from 6‑24) for each sample, of which a mean of 11.2% were disease‑associated and somatic events, while 34.7% were frameshift somatic In/Dels. From this analysis, alterations in the known oncogenes associated with PDAC were observed, including Kirsten rat sarcoma viral oncogene homolog (KRAS) mutations (93.7%) and inactivation of cyclin‑dependent kinase inhibitor 2A (CDKN2A) (50%), mothers against decapentaplegic homolog 4 (SMAD4) (50%), and tumor protein 53 (TP53) (56%). One case that was negative for KRAS exhibited a G13D neuroblastoma RAS viral oncogene homolog mutation. In addition, gene fusions were detected in 10 samples for a total of 23 different intra‑ or inter‑chromosomal rearrangements, however, a recurrent fusion transcript remains to be identified. SNP arrays identified macroscopic and cryptic cytogenetic alterations in 85% of patients. Gains were observed in the chromosome arms 6p, 12p, 18q and 19q which contain KRAS, GATA binding protein 6, protein kinase B and cyclin D3. Deletions were identified on chromosome arms 1p, 9p, 6p, 18q, 10q, 15q, 17p, 21q and 19q which involve TP53, CDKN2A/B, SMAD4, runt‑related transcription factor 2, AT‑rich interactive domain‑containing protein 1A, phosphatase and tensin homolog and serine/threonine kinase 11. In conclusion, genetic alterations in PDCA were observed to involve numerous pathways including cell migration, transforming growth factor‑β signaling, apoptosis, cell proliferation and DNA damage repair. However, signaling alterations were not observed in all tumors and key mutations appeared to differ between PDAC cases.

Antiprotease strategy in pancreatic cancer treatment: emergence from a preclinical study.

Objectives Resistance to gemcitabine is one of the main causes of treatment failure in pancreatic cancer. Compelling evidences have shown the involvement of nuclear factor &kgr;B (NF-&kgr;B) activation in such phenomenon. The protease inhibitor gabexate mesilate has been shown to inhibit NF-&kgr;B. We here investigated if combined treatment with this drug could improve gemcitabine antitumoral efficacy in pancreatic cancer cells. Methods The effect of gabexate mesilate and gemcitabine, both used at concentrations achievable in human plasma, was assessed on in vitro pancreatic cancer cell growth, invasion, and tumor angiogenesis. The molecular mechanism at the basis of these effects was also investigated. Results Gabexate mesilate significantly increased gemcitabine anti-invasive and antiangiogenic efficacy. This effect was related to inhibition of gemcitabine-induced NF-&kgr;B activation by gabexate mesilate, which prevented RelA/p65 nuclear translocation and resulted in metalloproteinase 2, metalloproteinase 9, vascular endothelial growth factor, and interleukin 8 down-regulation. Combined treatment with gabexate mesilate also inhibited gemcitabine-induced extracellular-regulated kinase 1/2 and AKT activation by increased expression of Raf kinase inhibitor protein and phosphatase and tensin homolog. Conclusions Combined treatment with gabexate mesilate sensitizes pancreatic cancer cells to gemcitabine by inhibition of the NF-&kgr;B pathway. The efficacy of this therapeutic strategy in pancreatic cancer patients remains to be established and deserves future clinical investigation.

Preoperative Gemcitabine and Oxaliplatin in a Patient with Ovarian Metastasis from Pancreatic Cystadenocarcinoma

We describe a case of clinical benefit and partial response with gemcitabine and oxaliplatin (GEMOX) in a young patient with ovarian metastasis from cystadenocarcinoma of the pancreas. A young woman complained of abdominal pain and constipation. Computed tomography (CT) and magnetic resonance imaging scans disclosed two bilateral ovarian masses with pancreatic extension. She underwent bilateral ovarian and womb resection. During surgery peritoneal carcinosis, a pancreatic mass and multiple abdominal lesions were found. The final diagnosis was mucinous pancreatic cystadenocarcinoma with ovarian and peritoneal metastases. She started chemotherapy with GEMOX (gemcitabine 1,000 mg/m2/d1 and oxaliplatin 100 mg/m2/d2 every 2 weeks). After 12 cycles of chemotherapy a CT scan showed reduction of the pancreatic mass. She underwent distal pancreatic resection, regional lymphadenectomy and splenectomy. Pathologic examination documented prominent fibrous tissue and few neoplastic cells with mucin-filled cytoplasm. Chemotherapy was continued with gemcitabine as adjuvant treatment for another 3 cycles. There is currently no evidence of disease. As reported in the literature, GEMOX is associated with an improvement in progression-free survival and clinical benefit in patients with advanced pancreatic cancer. This is an interesting case in whom GEMOX transformed inoperable pancreatic cancer into a resectable tumor.

Comparing RECIST and Choi’s Criteria to Evaluate Radiological Response to Chemotherapy in Patients with Advanced Pancreatic Cancer

Context Assessment of response after chemotherapy (CTH) for pancreatic cancer (PC) is currently based on RECIST criteria. In 2007 Choi et al . published a new classification system. Objectives To evaluate the accuracy of the two classification systems for radiological response to CTH in patients affected by advanced PC. Methods From 2006 to 2011, 61 untreated patients affected by advanced pancreatic adenocarcinoma underwent palliative CTH. Thirty-seven (60.7 %) had a locally advanced PC and 24 (39.3%) a metastatic disease. All patients were treated with a bemcitabine-based CTH. We assessed radiological response after three months of first-line therapy applying both RECIST criteria and Choi’s criteria, which consider changes both in size and in density at CT. We evaluated the accuracy in restaging, comparing the class of response with overall survival (OS). OS was calculated with Kaplan-Meier method. The concordance with the two classification systems was evaluated with Kendall’s test. The accuracy in restaging was assessed through log rank test. Results At restaging, using RECIST criteria, we registered 6 (9.8%) patients with partial response (PR), 32 (52.5%) with stable disease (SD), and 23 (37.7%) with disease progression (PD). Instead Choi’s criteria assessed 18 PR (29.5%), 12 SD (19.7%) and 31 PD (50.8%). The concordance test showed that the two systems matched (P<0.001). Comparing each classification with OS, we observed that patients with different prognosis were better stratified with Choi’s criteria. Using RECIST criteria we did not found any significant difference in OS between patients with PR (12 months), SD (16 months) and PD (10 months). Using Choi’s criteria we found that OS in patients with PR was similar to patients with SD with 16 and 19 months (P=0.634). Patients with PR had an OS significantly higher than patients with PD (16 vs . 9 months; P=0.009; RR=2.3). Conclusions Choi’s criteria seem to better assess radiological response of CTH in PC patients than RECIST criteria. Due to the small number of patients, larger prospective studies are needed.

SNP-Array High Resolution Cytogenetic Analysis of Resectable and Advanced Pancreatic Cancer

Context Pancreatic cancer (PC) is the fourth leading cause of cancer deaths. The molecular mechanisms involved in the high tumorigenicity of PC are not yet well-known. Methods Pancreatic tumor samples from 14 patients were collected by ultrasound-guided biopsy and used for DNA extraction. High resolution copy number analysis was performed on Affymetrix SNP array 6.0 and analyzed with segmentation algorithm against a reference of 270 Ceu HapMap individuals (Partek Genomic Suite). Results Nine out of 14 patients exhibited both macroscopic and cryptic cytogenetic alterations, with a mean of 10 copy number alterations (CNA) per patient, while 5 patients did not show any copy number gain or loss. Deletions outnumbered amplifications by more than 2 folds. The chromosomes showing more copy number gains were chromosomes 12, 18, 19, while chromosomes 6, 9, 17 and 18 were most frequently deleted. In particular, deletions on 9p21 encompassed CDKN2A and 2B tumor suppressor genes, that on chromosome 18q21 overlapped with SMAD4, the one on chromosome 6p21 included RUNX2, while TP53 and MAP2K4 were the target genes deleted on chromosome 17p13. Amplified regions on chromosome 12p12 encompassed KRAS and ETV6 genes, the one on chromosome 18q11 overlapped with GATA6, while that on 19q13 included AKT2. We observed that the number of alterations correlates with the clinical course, and in particular that patients with none to few alterations (≤6) showed a median time to disease progression and a median overall survival significantly longer than those having a high number of CNA (>6), with a time to disease progression of 13.7 vs . 4.1 months (P=0.015) and an overall survival of 14.6 vs . 4.8 months (P=0.035). Conclusions High resolution cytogenetic analysis by SNP-array has the potential to uncover the genetic alterations carried by pancreatic tumors, and find new markers related to patient prognosis.

Abstract LB-144: Tff2 labels pancreatic progenitors that lack proliferative potential during tissue regeneration but can serve as the origin of pancreatic cancer

While controversy over the existence of adult pancreatic stem cells persists, it is now appreciated that the acinar compartment of the pancreas harbors heterogeneous progenitors. Recent single-cell analysis also demonstrated the presence of molecularly distinct, albeit morphologically identical, acinar cell sub-lineages. Previously, using lineage-tracing approach, we reported the Dclk1+ facultative progenitors that are critical for pancreatic regeneration. Here, we identified a different pancreatic progenitor-like subpopulation which is labelled by trefoil factor 2 (Tff2), a known progenitor marker and capable of tracing multiple cell lineages in the stomach. In addition, Tff2 molecules have been shown to play a suppressive role in PDAC progression. We utilized constitutive Tff2Cre and inducible Tff2CreERT2-DTR mice which were generated through modification of a BAC allele. We crossed Tff2CreERT2-DTR with reporter mice (R26R-mTmG, -tdTomato) to trace Tff2 labeled cells, and found that Tff2 labels ~2 % of the overall population in the adult acinar compartment, which showed slow proliferation (1 year, descendants Citation Format: Zhengyu Jiang, Bernhard W. Renz, Marina Macchini, Tanaka Takayuki, Ryota Takahashi, Giovanni Valenti, Woosook Kim, Wenju Chang, Yoku Hayakawa, Kosuke Sakitani, Moritz Middelhoff, Zinaida Dubeykovskaya, Timothy Chu, Karan Nagar, Yagnesh Tailor, Chythra R. Chandregowda, Akanksha Anand, Samuel Asfaha, Alina C. Iuga, Timothy C. Wang. Tff2 labels pancreatic progenitors that lack proliferative potential during tissue regeneration but can serve as the origin of pancreatic cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-144. doi:10.1158/1538-7445.AM2017-LB-144

Whole Transcriptome Sequencing Reveals Somatic HMGCR Mutation in a Case of Pancreatic Adenocarcinoma with Long-Term Therapy Response

Context We merged clinical history of a locally advanced pancreatic cancer (LAPC) patient with data obtained from a whole transcriptome massively parallel sequencing (RNASeq). Case report A 56-year-old man with histological diagnosis of LAPC. After obtained informed consent, we collected a fragment of pancreatic lesion. Patient received 6 induction cycles treatment with gemcitabine and oxaliplatin (GEMOX) from November 2011, followed by chemoradiotherapy with bi-weekly gemcitabine 50 mg/m 2 for 6 weeks. CT-scan demonstrated partial response, so patient received additional 12 cycles of GEMOX, with further response, which currently persist since 17 months (to 3.8 cm vs . 2.5 cm). At the same time, the RNASeq was performed at 75x2 bp on a HiScanSQ (Illumina Inc., San Diego, CA, USA) platform. Single nucleotide variants (SNVs) were detected with SNVMix2 and filtered on dbSNP, 1000 Genomes Project, and Cosmic databases. Non-synonymous SNVs were analyzed with SNPsG ATXN10-TMEM49; chromosome 22 and 17) and 2 out-of-frame fusions [ t (15;3) and t (19;22)] leading to SMAD3-KIAA1143 and LTBP4-SPATS2L, both disrupting genes of the TGFbeta pathway. Conclusion We found a novel somatic alteration involving HMGCR in LAPC. Due to the key role of HMGCR in cellular transformation, we hypothesize a strong potential in the development and outcome of LAPC, whose the optimal treatment remains to be elucidated. Trials that integrate RNASeq data with clinical options are needed.