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To elucidate the prognostic impact of sarcopenia before and after neoadjuvant chemotherapy (NAC) for pancreatic cancer (PC).We retrospectively studied 75 consecutive PC patients who underwent neoadjuvant gemcitabine plus S-1 combination therapy followed by pancreatectomy between 2008 and 2016. According to the skeletal muscle volume index (SMI), the patients were divided into the muscle attenuation group (MAG) and normal group (NG) before or after NAC. Prognostic factors for overall survival (OS) were analyzed by Cox proportional hazards models.The MAG showed significantly poorer OS than the NG before and after NAC. Pre-NAC, median OS was 20.0 months in the MAG versus 49.0 months in the NG (p = 0.006). Post-NAC, median OS was 21.3 months in the MAG versus 48.8 months in the NG (p = 0.014). Multivariate analysis, excluding muscle attenuation after NAC because of confounding factors and lower hazard ratio (2.08, 95% confidence interval: 1.14-3.78, p = 0.016) than that before NAC (2.14, 1.23-3.70, p = 0.007) by univariate analysis, revealed the following independent prognostic factors: muscle attenuation pre-NAC (2.25, 1.26-4.05, p = 0.007); borderline resectability (1.96, 1.04-3.69, p = 0.038); operative blood loss (2.60, 1.38-4.88, p = 0.003); and distant metastasis (3.31, 1.40-7.82, p = 0.006).Sarcopenia before and after NAC for PC is suggested to be a poor prognostic factor, with a stronger impact before than after NAC.

Mammary gland homeostasis is maintained by adult tissue stem-progenitor cells residing within the luminal and basal epithelia. Dysregulation of mammary stem cells is a key mechanism for cancer development. However, stem cell characterization is challenging because reporter models using cell-specific promoters do not fully recapitulate the mammary stem cell populations. We previously found that a 270-basepair Runx1 enhancer element, named eR1, marked stem cells in the blood and stomach. Here, we identified eR1 activity in a rare subpopulation of the ERα-negative luminal epithelium in mouse mammary glands. Lineage-tracing using an eR1-CreERT2 mouse model revealed that eR1+ luminal cells generated the entire luminal lineage and milk-secreting alveoli—eR1 therefore specifically marks lineage-restricted luminal stem cells. eR1-targeted-conditional knockout of Runx1 led to the expansion of luminal epithelial cells, accompanied by elevated ERα expression. Our findings demonstrate a definitive role for Runx1 in the regulation of the eR1-positive luminal stem cell proliferation during mammary homeostasis. Our findings identify a mechanistic link for Runx1 in stem cell proliferation and its dysregulation in breast cancer. Runx1 inactivation is therefore likely to be an early hit in the cell-of-origin of ERα+ luminal type breast cancer.

Metachronous tumors arising in the remnant bile duct after surgical resection for primary biliary tract cancers (BTCs) are rarely treated surgically and have not been well documented. This study aimed to clarify the clinicopathological and genomic features of metachronous tumors arising in the remnant bile duct. Consecutive 12 patients who underwent resection for metachronous BTCs arising in the remnant bile duct after primary surgical resection between 2008 and 2020 were enrolled. Clinicopathological analysis and genomic analysis using targeted amplicon sequencing for 31 biliary tract cancer-related genes, including TP53, APC, ARID1A, ARID2, BAP1, CDKN2A, CTNNB1, ELF3, ERBB2, GNAS, IDH1, KRAS, and SMAD4, and immunohistochemistry for p53, p16, SMAD4, ARID1A, and β-catenin, were performed on 12 matched pair of primary and metachronous BTCs. In the 12 patients, 7 metachronous tumors developed antegradely in the lower portion of the biliary tree, and the remaining 5 metachronous tumors developed retrogradely in the upper portion, with negative bile duct margin at the initial operations. Molecular analysis revealed mutations and copy number alterations in TP53 (87.5%), APC (20.8%), CTNNB1 (20.8%), KRAS (12.5%), GNAS (8.3%), and RNF43 (8.3%). In comparison analysis, the matched primary and metachronous tumors shared identical genomic features in 10 cases, except in 2 cases showing metachronous perihilar and distal bile duct carcinomas after gallbladder cancer resection. Seven patients survived without recurrence, 5 showed postoperative local recurrences, and 2 died. Nine patients achieved 5-year overall survival after primary surgery. In conclusion, among the 12 patients with subsequent metachronous BTCs, 10 originated from neoplastic clones of the primary carcinoma, indicating recurrence due to intramural metastases or intraductal disseminations. Repeated surgical approach for metachronous BTCs may provide definitive local control and potentially prolong survival in these patients.

The stomach corpus is constantly subjected to damage from acid, pathogens, and chemical carcinogens. Although adult stomach stem cells must respond quickly to replace the damaged tissues, they need to be tightly regulated to ensure controlled self-renewal and lineage fidelity. Tumors have been described as “wounds that do not heal.” The corpus epithelium, with its high turnover, is a good model system to study stem cell proliferation and cancer initiation. The discoveries of various stem cell markers have enabled us to visualize stem cells and trace their path to differentiation or malignancy. Here, we review how multiple stomach stem cell markers shaped our knowledge and yet fueled conflict in the interpretation of stomach homeostasis and cell-of-origin in cancer. We will also discuss our recent finding of a novel proliferating stem cell marker IQ motif-containing GTPase activating protein 3 (IQGAP3), its ability to induce plasticity in differentiated cells during tissue damage, and the implications to carcinogenesis.

Background & Aims Metaplasia and dysplasia in the corpus are reportedly derived from de-differentiation of chief cells. However, the cellular origin of metaplasia and cancer remained uncertain. Therefore, we investigated whether pepsinogen C (PGC) transcript–expressing cells represent the cellular origin of metaplasia and cancer using a novel Pgc-specific CreERT2 recombinase mouse model. Methods We generated a Pgc-mCherry-IRES-CreERT2 (Pgc-CreERT2) knock-in mouse model. Pgc-CreERT2/+ and Rosa-EYFP mice were crossed to generate Pgc-CreERT2/Rosa-EYFP (Pgc-CreERT2/YFP) mice. Gastric tissues were collected, followed by lineage-tracing experiments and histologic and immunofluorescence staining. We further established Pgc-CreERT2;KrasG12D/+ mice and investigated whether PGC transcript–expressing cells are responsible for the precancerous state in gastric glands. To investigate cancer development from PGC transcript–expressing cells with activated Kras, inactivated Apc, and Trp53 signaling pathways, we crossed Pgc-CreERT2/+ mice with conditional KrasG12D, Apcflox, Trp53flox mice. Results Expectedly, mCherry mainly labeled chief cells in the Pgc-CreERT2 mice. However, mCherry was also detected throughout the neck cell and isthmal stem/progenitor regions, albeit at lower levels. In the Pgc-CreERT2;KrasG12D/+ mice, PGC transcript–expressing cells with KrasG12D/+ mutation presented pseudopyloric metaplasia. The early induction of proliferation at the isthmus may reflect the ability of isthmal progenitors to react rapidly to Pgc-driven KrasG12D/+ oncogenic mutation. Furthermore, Pgc-CreERT2;KrasG12D/+;Apcflox/flox mice presented intramucosal dysplasia/carcinoma and Pgc-CreERT2;KrasG12D/+;Apcflox/flox;Trp53flox/flox mice presented invasive and metastatic gastric carcinoma. Conclusions The Pgc-CreERT2 knock-in mouse is an invaluable tool to study the effects of successive oncogenic activation in the mouse corpus. Time-course observations can be made regarding the responses of isthmal and chief cells to oncogenic insults. We can observe stomach-specific tumorigenesis from the beginning to metastatic development.

ObjectiveTissue stem cells are central regulators of organ homoeostasis. We looked for a protein that is exclusively expressed and functionally involved in stem cell activity in rapidly proliferating isthmus stem cells in the stomach corpus.DesignWe uncovered the specific expression of Iqgap3 in proliferating isthmus stem cells through immunofluorescence and in situ hybridisation. We performed lineage tracing and transcriptomic analysis of Iqgap3 +isthmus stem cells with the Iqgap3-2A-tdTomato mouse model. Depletion of Iqgap3 revealed its functional importance in maintenance and proliferation of stem cells. We further studied Iqgap3 expression and the associated gene expression changes during tissue repair after tamoxifen-induced damage. Immunohistochemistry revealed elevated expression of Iqgap3 in proliferating regions of gastric tumours from patient samples.ResultsIqgap3 is a highly specific marker of proliferating isthmus stem cells during homoeostasis. Iqgap3+isthmus stem cells give rise to major cell types of the corpus unit. Iqgap3 expression is essential for the maintenance of stem potential. The Ras pathway is a critical partner of Iqgap3 in promoting strong proliferation in isthmus stem cells. The robust induction of Iqgap3 expression following tissue damage indicates an active role for Iqgap3 in tissue regeneration.ConclusionIQGAP3 is a major regulator of stomach epithelial tissue homoeostasis and repair. The upregulation of IQGAP3 in gastric cancer suggests that IQGAP3 plays an important role in cancer cell proliferation.

Background The epithelial-mesenchymal transition (EMT) in cancer cells has been shown to closely associate with the survival and drug resistance of cancer cells. We recently provided evidence that Wnt signal activator leucine-rich repeat in flightless-1-interacting protein 1 (LRRFIP1) regulates EMT in pancreatic cancer. LRRFIP1 silencing inhibits the translocation of β-catenin to the nucleus, which led to reverse EMT in cancer cells. It was suggested that LRRFIP1 was implicated in gemcitabine sensitivity by regulating EMT signaling. Methods Gemcitabine chemosensitivity was investigated in LRRFIP1-knockdown pancreatic cancer cells (PANC-1 and MIA Paca-2). In addition, the effects of LRRFIP1 knockdown on JNK/SAPK (stress activated-protein kinase) signaling and apoptosis were evaluated. Results LRRFIP1 silencing accelerates gemcitabine-induced caspase activity and cell death in pancreatic cancer cells. It was also revealed that gemcitabine-induced phosphorylation of c-Jun N-terminal kinase (JNK) and c-Jun were increased in LRRFIP1 knockdown cells. The activation of JNK/c-Jun in LRRFIP1-knockdown cells was significantly diminished by the inhibition of Rac activity. It was confirmed that the acquisition of gemcitabine sensitivity by LRRFIP1 silencing largely depends on the stimulation of JNK/SAPK (stress activated-protein kinase) signaling. Conclusions Our findings suggest that reversing EMT and transient activation of JNK might be essential for the gemcitabine sensitivity in LRRFIP1 knockdown pancreatic cancer cells. Our discoveries highlight the potential role of LRRFIP1 in the chemosensitivity related to the regulation of EMT signaling.

OBJECTIVES Platelet-derived growth factor receptor beta (PDGFRβ) and hepatocyte growth factor receptor (MET) expressed on pancreatic stellate cells (PSCs) are suggested as important components modulating the interactions between pancreatic cancer cells (PCCs) and PSCs. The objective of this study is to clarify the effect of MK2461, a multikinase inhibitor targeting MET and PDGFRβ, on the interaction between PCCs and PSCs. METHODS In this study, we profiled the expression of receptor tyrosine kinases (including PDGFRβ and MET) in pancreatic cancer with quantitative targeted absolute proteomics using liquid chromatography tandem mass spectrometry. In addition, the effect of MK2461 on PCC-PSC interaction was investigated using PSCs prepared from pancreatic cancer tissues. RESULTS In PSCs, PDGFRβ and MET were upregulated compared with other receptor tyrosine kinases. Conditioned medium from PSCs promoted the proliferation of PCCs, and vice versa. Moreover, MK2461 suppressed the effects of conditioned medium on PCCs and PSCs. Finally, MK2461 significantly inhibited tumor growth in mice coinjected with PCCs and PSCs. CONCLUSIONS The PDGFRβ and MET may play a critical role in the interaction between PCCs and PSCs, which was modulated by MK2461. Therefore, MK2461 may have therapeutic potential in the treatment of pancreatic cancer.

The canonical Wnt/β-catenin signaling pathway has been shown to promote the epithelial-mesenchymal transition (EMT), which is a crucial process in multiple embryonic developmental processes and the progression of carcinomas. We recently provided evidence that leucine-rich repeat flightless-1-interacting protein 1 (LRRFIP1) promotes cancer metastasis and invasion. In the present study, we identified the signaling elements targeted by LRRFIP1 for promotion of the EMT in pancreatic and lung cancer. LRRFIP1 silencing reversed the EMT, as shown by increased expression of E-cadherin (an epithelial marker) and decreased expression of vimentin (a mesenchymal marker). Silencing of LRRFIP1 up-regulated phosphorylation of β-catenin and decreased its nuclear localization by targeting the β-catenin destruction complex. The expression of β-catenin and E-cadherin in the plasma membrane fraction was increased in LRRFIP1 silenced cancer cells, and the migration and invasion capabilities were strongly inhibited. In addition, this protein was highly expressed at the invasion front of malignant tissue collected from pancreatic cancer patients. Consequently, our data strongly suggested that LRRFIP1 played an important role in the invasion of carcinoma cells. Our data provide experimental evidence that LRRFIP1 is an attractive candidate for targeted therapy in human cancers.

Highlights • Dilatation of the interposed jejunal pouch developed after proximal gastrectomy. • Shock state with portal venous gas was restored after conservative therapy. • The pouch dilatation recurred soon after resuming oral ingestion. • Resection of the pouch with R-Y esophagojejunostomy relieved the patient. • Surgical intervention should be considered for refractory pouch dilatation., Introduction The jejunal pouch interposition (JPI) after proximal gastrectomy (PG) was proposed as a reconstructive procedure to provide a gastric reservoir substitute and prevent postgastrectomy syndrome. However, food residue remaining in some of the pouches resulted in the adverse effect of abdominal bloating, thereby body weight loss. Here, we report a rare case with an extreme dilation of the interposed jejunal pouch (JP) 8 years after PG, requiring pouch resection. Presentation of case A 65-year-old-man who had undergone PG with an inverted U-shaped JPI for early gastric cancer 8 years previously, suffered from shock after right hip joint implantation. Abdominal enhanced CT scan revealed an extremely dilated JP accompanied by portal venous gas. After 5 months of conservative therapy, he underwent resection of the JP and gastric remnant with Roux-en-Y esophagojejunostomy reconstruction. After the operation, the patient has remained in good health for over 3 years. Discussion and conclusion Long-term operative outcome following pouch operation for gastric cancer still remains controversial. Surgical intervention should be considered when we encounter patients who have refractory pouch dilatation after surgery for gastric cancer.

The precise relationship between GCF2 expression and carcinogenesis has not yet been established. To clarify the metastatic potential of GCF2 in colorectal cancer, HT-29 cells stably suppressing GCF2 expression were injected into the spleens of severe combined immunodeficient (SCID) mice. GCF2 suppression reduced the number of metastatic foci in the liver and reduced fibronectin-induced cell adhesion, migration, and invasion. Downstream from the integrin signaling pathways, GCF2 regulates RhoA interaction with the RGS domain of Leukemia associated RhoGEF (LARG). Altogether, our results suggest that GCF2 plays an important role in colorectal cancer metastasis by regulating RhoA-induced cell adhesion, migration, and invasion.

Pancreatic cancer is characterized excessive desmoplasia, which occupies 80% of pancreatic cancer tissue and mainly consists of pancreatic stellate cells (PSCs). Desmoplasia has been shown to play an important role in the progression, invasion, and metastasis of pancreatic cancer and has been implicated in the development of resistance to chemotherapy and radiotherapy. Growth factors are one of the components modulating the interactions between pancreatic cancer cells (PCCs) and PSCs. Therefore, blocking growth factor signaling could suppress cancer progression. In this study, we profiled the expression of receptor tyrosine kinases (RTKs) with quantitative targeted absolute proteomics using liquid chromatography tandem mass spectrometry (LC-MS/MS) in PCCs and PSCs. In PCCs, epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (MET) levels were elevated compared with those in PSCs. In PSCs, platelet-derived growth factor receptor beta (PDGFRβ) and MET were upregulated compared with other RTKs. Conditioned medium from PSCs promoted the proliferation of PCCs, and vice versa. In addition, MK2461, a multikinase inhibitor targeting MET and PDGFRβ, suppressed the effects of conditioned medium on PCCs and PSCs. In addition, MK2461 significantly inhibited tumor growth in mice xenograft model. In conclusion, PDGFRβ and MET may play a critical role in the interaction between PCCs and PSCs. Moreover, MK2461 may have therapeutic potential in the treatment of pancreatic cancer by targeting the interaction between PCCs and PSCs. Citation Format: Koetsu Inoue, Hideo Ohtsuka, Fuyuhiko Motoi, Daisuke Douchi, Shuhei Kawasaki, Kei Kawaguchi, Kunihiro Masuda, Koji Fukase, Shinobu Ohnuma, Takeshi Naitoh, Yu Katayose, Shinichi Egawa, Michiaki Unno. MK2461 suppress progression of pancreatic cancer disrupting interaction between pancreatic cancer cells and stellate cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 404. doi:10.1158/1538-7445.AM2015-404