Relationship between prognostic impact of N3 lymph node metastasis at the root of the feeding artery and location of colon cancer.

PURPOSE: To determine whether N3 nodal involvement predicts outcomes and whether its prognostic implications vary with tumor location in patients with Stage III colon cancer (CC). METHODS: We defined N3 as lymph node metastases near the bases of the major feeding arteries. We retrospectively examined recurrence rates and patterns by tumor location and sites of lymph node metastases in 57 patients with N3 CC who had undergone curative resections between January 2000 and March 2019. Survival analysis was performed to compare the prognoses of patients with and without N3 lymph node metastasis. RESULTS: Most N3 patients had large tumors (T ≥ 3); five had T2 disease. Recurrence occurred quickly in one patient with T2N3M0 disease. Multivariate survival analysis demonstrated that N3 lymph node metastasis is an independent predictor of poor prognosis in Stage III CC patients (P < 0.001). Categorizing N3 patients according to UICC-TNM staging system does not stratify risk of recurrence (P = 0.970). To investigate the impact of tumor location on recurrence risk, we classified N3 CC into two subtypes according to tumor location: metastasis at the base of the superior mesenteric artery in right-sided CC and inferior mesenteric artery in left-sided CC. The former was found to have a statistically significant poorer prognosis than the latter (P = 0.091). CONCLUSION: N3 is a robust prognostic marker in CC patients. Recurrence risk varies by tumor location. N3 right-sided CCs with lymph node metastasis at the base of the superior mesenteric artery have poorer prognoses than do N3 left-sided CCs.

Preoperative prediction of malignancy and surgical treatment strategy in appendiceal tumors: multicenter review of 51 consecutive cases.

PURPOSE: A diagnostic and treatment strategy for appendiceal tumors (ATs) has not been established. We aimed to evaluate our treatment strategy in ATs, including laparoscopic surgery (LS), and to identify preoperative malignancy predictors. METHODS: A total of 51 patients between 2011 and 2021 were retrospectively reviewed. Data, including tumor markers and imaging findings, were compared between carcinoma and non-carcinoma patients. Validity of planned operation was evaluated based on pathological diagnosis. RESULTS: Twenty-five patients were diagnosed with carcinoma, 13 with low-grade mucinous neoplasm, and 13 with other diseases. Symptoms were more commonly present in carcinoma patients than in non-carcinoma patients (68.0% vs. 23.1%, p = 0.001). Elevated CEA and CA19-9 were more frequently observed in carcinoma patients than in non-carcinoma patients (p < 0.01 and p = 0.04, respectively). Five carcinoma patients had malignancy on biopsy, compared with zero non-carcinoma patients. Significant differences were noted in the percentages of carcinoma and non-carcinoma patients with solid enhanced mass (41.7% vs. 0%, p < 0.001) and tumor wall irregularity (16.7% vs. 0%, p = 0.03) on imaging. Although the sensitivity was not high, the specificity and positive predictive value of these findings were 100%. Forty-two patients (82.4%) underwent LS as minimally invasive exploratory and/or radical operation, of whom 2 were converted to open surgery for invasion of adjacent organ. No patients had intraoperative complications or postoperative mortality. CONCLUSION: Clinical symptoms, elevated tumor markers, and worrisome features of solid enhanced mass and tumor wall irregularity on imaging can be malignancy predictors. For management of ATs, LS is feasible and useful for diagnosis and treatment.

Long-term effects of laparoscopic lateral pelvic lymph node dissection on urinary retention in rectal cancer.

BACKGROUND: The addition of lateral pelvic lymph node dissection (LPLND) in rectal cancer surgery has been reported to increase the incidence of post-operative urinary retention. Here, we assessed the predictive factors and long-term outcomes of urinary retention following laparoscopic LPLND (L-LPLND) with total mesorectal excision (TME) for advanced lower rectal cancer. METHODS: This retrospective single-institutional study reviewed post-operative urinary retention in 71 patients with lower rectal cancer who underwent L-LPLND with TME. Patients with preoperative urinary dysfunction or who underwent unilateral LPLND were excluded. Detailed information regarding patient clinicopathologic characteristics, post-void residual urine volume, and the presence or absence of urinary retention over time was collected from clinical and histopathologic reports and telephone surveys. Urinary retention was defined as residual urine > 100 mL and the need for further treatment. RESULTS: Post-operative urinary retention was observed in 25/71 patients (35.2%). Multivariate analysis revealed that blood loss ≥ 400 mL [odds ratio (OR) 4.52; 95% confidence interval (CI) 1.24-16.43; p = 0.018] and inferior vesical artery (IVA) resection (OR 8.28; 95% CI 2.46-27.81; p < 0.001) were independently correlated with the incidence of urinary retention. Furthermore, bilateral IVA resection caused urinary retention in more patients than unilateral IVA resection (88.9% vs 47.1%, respectively; p = 0.049). Although urinary retention associated with unilateral IVA resection improved relatively quickly, urinary retention associated with bilateral IVA resection tended to persist over 1 year. CONCLUSION: We identified the predictive factors of urinary retention following L-LPLND with TME, including increased blood loss (≥ 400 mL) and IVA resection. Urinary retention associated with unilateral IVA resection improved relatively quickly. L-LPLND with unilateral IVA resection is a feasible and safe procedure to improve oncological curability. However, if oncological curability is guaranteed, bilateral IVA resection should be avoided to prevent irreversible urinary retention.

Adipose tissue-derived stromal cells are sources of cancer-associated fibroblasts and enhance tumor progression by dense collagen matrix.

Although recent studies revealed that adipose tissue accelerates pancreatic tumor progression with excessive extracellular matrix, key players for desmoplasia in the adipose microenvironment remains unknown. Here, we investigated the roles of adipose tissue-derived stromal cells (ASCs) in desmoplastic lesions and tumor progression by in vitro and in vivo experiments. In a three-dimensional (3-D) organotypic fat invasion model using visceral fat from CAG-EGFP mice, GFP-positive fibroblastic cells infiltrated toward cancer cells. When tumor cells were inoculated into transplanted visceral fat pads in vivo, tumor weights and stromal components were enhanced compared to subcutaneous and orthotopic tumor cells inoculated without fat pads. Expression of αSMA in established human ASCs was lower compared to cancer associated fibroblasts, and the 3-D collagen matrices produced by ASCs cultured in cancer cell-conditioned medium changed from loose to dense structures that affected the motility of cancer cells. Microarray analyses revealed upregulation of S100A4 in ASCs, while S100A4-positive stromal cells were observed at extrapancreatic invasion sites of human pancreatic cancer. The present findings indicate that ASCs are recruited to extrapancreatic invasion sites and produce dense collagen matrices that lead to enhanced tumor progression. Both inhibition of ASCs recruitment and activation could lead to a novel antistromal therapy.

Autophagy Is Required for Activation of Pancreatic Stellate Cells, Associated With Pancreatic Cancer Progression and Promotes Growth of Pancreatic Tumors in Mice.

BACKGROUND & AIMS: Pancreatic stellate cells (PSCs) change from a quiescent to activated state in the tumor environment and secrete extracellular matrix (ECM) molecules and cytokines to increase the aggressiveness of tumors. However, it is not clear how PSCs are activated to produce these factors, or whether this process can be inhibited. PSCs have morphologic and functional similarities to hepatic stellate cells, which undergo autophagy to promote fibrosis and tumor growth. We investigated whether autophagy activates PSCs, which promotes development of the tumor stroma and growth of pancreatic tumors in mice. METHODS: We used immunofluorescence microscopy and immunohistochemistry to analyze pancreatic tumor specimens from 133 patients who underwent pancreatectomy in Japan from 2000 to 2009. PSCs were cultured from pancreatic tumor tissues or tissues of patients with chronic pancreatitis; these were analyzed by immunofluorescence microscopy, immunoblots, quantitative reverse transcription polymerase chain reaction, and in assays for invasiveness, proliferation, and lipid droplets. Autophagy was inhibited in PSCs by administration of chloroquine or transfection with small interfering RNAs. Proteins were knocked down in immortalized PSCs by expression of small hairpin RNAs. Cells were transplanted into pancreatic tails of nude mice, and tumor growth and metastasis were quantified. RESULTS: Based on immunohistochemical analyses, autophagy was significantly associated with tumor T category (P = .018), histologic grade (P = .001), lymph node metastases (P < .001), stage (P = .009), perilymphatic invasion (P = .001), and perivascular invasion (P = .003). Autophagy of PSCs was associated with shorter survival times of patients with pancreatic cancer. PSC expression of microtubule-associated protein 1 light chain 3, a marker of autophagosomes, was associated with poor outcomes (shorter survival time, disease recurrence) for patients with pancreatic cancer (relative risk of shorter survival time, 1.56). Immunoblots showed that PSCs from pancreatic tumor samples expressed higher levels of markers of autophagy than PSCs from chronic pancreatitis samples. Inhibitors of autophagy increased the number of lipid droplets of PSCs, indicating a quiescent state of PSCs, and reduced their production of ECM molecules and interleukin 6, as well as their proliferation and invasiveness in culture. PSCs exposed to autophagy inhibitors formed smaller tumors in nude mice (P = .001) and fewer liver metastases (P = .018) with less peritoneal dissemination (P = .018) compared to PSCs not exposed to autophagy inhibitors. CONCLUSIONS: Autophagic PSCs produce ECM molecules and interleukin 6 and are associated with shorter survival times and disease recurrence in patients with pancreatic cancer. Inhibitors of PSC autophagy might reduce pancreatic tumor invasiveness by altering the tumor stroma.

A case report of sigmoid colon cancer with the inferior mesenteric artery directly originating from the superior mesenteric artery.

BACKGROUND: There are few reports describing the unusual origin of the inferior mesenteric artery (IMA). We report a rare case of advanced sigmoid colon cancer with the IMA arising from the superior mesenteric artery. CASE PRESENTATION: A 59-year-old man with diarrhea and abdominal distention was diagnosed with advanced sigmoid colon cancer. Colonoscopy revealed a semi-circumferential cancer lesion in the sigmoid colon. Enhanced CT scan and CT angiography showed that the IMA directly originated from the superior mesenteric artery at the level of the second lumbar vertebra. PET-CT suggested metastases in the para-intestinal lymph nodes and the liver, but not in the central lymph nodes along the IMA. Preoperative diagnosis was sigmoid colon cancer cT4aN2aM1a cStage IVA(UICC, 8th edition). We performed laparoscopic complete resection as the radical treatment of the primary region prior to resection of the liver metastases. Intraoperative findings showed that the IMA was running parallel to the abdominal aorta; meanwhile, the colonic autonomic nerve was supplied from the lumbar splanchnic nerve at the caudal side of the duodenum. Central lymph nodes around the colonic autonomic nerve were dissected en bloc with the regional lymph nodes. Pathological radical resection including the regional lymph nodes metastasis was achieved. Two months later, complete resection of the liver metastasis was performed. After the adjuvant chemotherapy, no recurrence was observed 1.5 years after the liver resection was performed. CONCLUSIONS: Preoperative confirmation of the anatomy helped us to safely complete radical surgery in a patient with unusual bifurcation of the IMA.

Strong impact of sarcopenic state defined by skeletal muscle mass index on postoperative complication of Crohn's disease patients.

Background: Malnutrition impacts the clinical course of Crohn's disease; however, there is little evidence of its influence on perioperative adverse events. We assessed whether nutritional indicators are associated with postoperative complications in surgical treatment of Crohn's disease. Methods: 137 patients with Crohn's disease who underwent surgical treatment between January 2011 and December 2020 were included. Skeletal muscle index was calculated by a single CT slice. We analyzed the risk factors for adverse events. Results: 37 % of patients had postoperative complications. Adverse events occurred more frequently in patients with high serum C-reactive protein, low serum albumin, prognostic nutritional index <38.3, skeletal muscle index <38.9 cm2/m2, abdominoperineal resection, long surgical duration, and mass hemorrhage. Among patients with skeletal muscle index <38.9 cm2/m2, patients who experienced adverse events had higher visceral fat index compared with those who did not (0.85 vs. 0.45, P = 0.04). Multivariate analysis revealed that skeletal muscle index <38.9 cm2/m2 and low serum albumin were the independent risk factors for postoperative complications (Odds ratio, 2.85; 95 % confidence interval, 1.13-7.16; P = 0.03, 2.62; 1.09-6.26; P = 0.03, respectively). Separated by sex, low serum albumin (<3.5 and <2.8 g/dL, male and female, respectively) and skeletal muscle index (<38.9 and <36.6 cm2/m2, male and female, respectively) were statistically related to postoperative complications. Conclusions: Skeletal muscle index is the most useful nutritional predictor of postoperative complications in Crohn's disease patients among other nutritional indices. We believe that these patients are at high risk of postoperative complications and need appropriate nutritional support in the perioperative period.

Nonmass-forming type anorectal cancer with pagetoid spread: A report of two cases.

Pagetoid spread (PS) of anorectal cancer is relatively rare and associated with poor prognosis. While a primary tumorous lesion is usually obvious in most PS cases, we experienced two cases of nonmass-forming type anorectal cancer with PS. It remains challenging to decide strategies. In both cases, histological findings of a perianal skin biopsy showed proliferation of atypical cells that were positive for cytokeratin (CK) 7, CK20, and caudal type homeobox 2 and negative for Gross cystic disease fluid protein 15, suggesting PS. Abdominoperineal resection (APR) with extensive anal skin resection was performed in both patients. The pathological diagnosis in each was nonmass-forming type anorectal cancer with PS. Neither has experienced recurrence in postoperative courses. Even nonmass-forming type anorectal cancer with PS could have high malignant potentials. APR with lymph nodes dissection and wide skin excision and regular surveillance might be necessary.

Cross-sectional area of psoas muscle as a predictive marker of anastomotic failure in male rectal cancer patients: Japanese single institutional retrospective observational study.

PURPOSE: Preoperative sarcopenia worsens postoperative outcomes in various cancer types including colorectal cancer. However, we often experienced postoperative anastomotic leakage in muscular male patients such as Judo players, especially in rectal cancer surgery with lower anastomosis. It is controversial whether the whole skeletal muscle mass impacts the potential for anastomotic failure in male rectal cancer patients. Thus, the purpose of this study was to clarify whether skeletal muscle mass impacts anastomotic leakage in rectal cancer in men. METHODS: We reviewed the medical charts of male patients suffering from rectal cancer who underwent colo-procto anastomosis below the peritoneal reflection without a protective diverting stoma. We measured the psoas muscle area and calculated the psoas muscle index. RESULTS: One hundred ninety-seven male rectal cancer patients were enrolled in this study. The psoas muscle index was significantly higher in patients with anastomotic leakage (P<0.001). Receiver operating characteristic curve determined the optimal cut-off value of the psoas muscle index for predicting anastomotic leakage as 812.67 cm2/m2 (sensitivity of 60% and specificity of 74.3%). Multivariate analysis revealed that high psoas muscle index (risk ratio [RR], 3.933; P<0.001; 95% confidence interval [CI], 1.917-8.070) and super low anastomosis (RR, 2.792; P=0.015; 95% CI, 1.221-6.384) were independent predictive factors of anastomotic leakage. CONCLUSION: This study showed that male rectal cancer patients with a large psoas muscle mass who underwent lower anastomosis had a higher rate of postoperative anastomotic leakage.

Clinical impact of remnant lymphatic invasion on the recurrence of esophageal squamous cell carcinoma after esophagectomy with neoadjuvant chemotherapy.

For stage II and III esophageal squamous cell carcinoma (ESCC), neoadjuvant chemotherapy (NAC) followed by esophagectomy is recommended in the Japanese guidelines for the diagnosis and treatment of esophageal cancer. However, recurrence of ESCC is common regardless of the NAC regimen and surgical method, and NAC demonstrates limited efficacy against recurrence. Therefore, the present study was conducted to identify risk factors of recurrence of ESCC with surgery after NAC. The outcomes of 51 patients who underwent esophagectomy for ESCC after NAC from 2010 to 2017 at Kyushu University Hospital were retrospectively analyzed. A total of 52 patients with ESCC without NAC followed by esophagectomy from 2001 to 2017 were selected for comparison. Among patients who underwent NAC followed by surgery, only lymphatic invasion (LY; hazard ratio, 2.761; 95% CI, 1.86-6.43, P=0.018) was an independent factor significantly associated with 3-year recurrence-free survival in the multivariate analysis. In patients with pathologic lymph node metastasis (pN) and no LY after NAC, there was significantly less recurrence compared with patients with pN and LY (P=0.0085), whereas in patients without LY after NAC, the presence of pN was not significantly associated with recurrence (P=0.2401). There were significantly fewer LY (+) patients in the NAC (+) group (P=0.0158) compared with those in the NAC (-) group. The presence of LY was an independent risk factor for recurrence of ESCC after esophagectomy following NAC. Overall, adjuvant treatment after surgery may be required in cases with remnant LY after NAC.

Predictive factors associated with relapse of stage II/III colon cancer treated with peroral anti-cancer agents in the adjuvant setting.

Postoperative adjuvant chemotherapy for patients with stage III colon cancer (CC) is regarded as the standard treatment worldwide for outcome improvement and relapse prevention. Similarly, high-risk stage II CC requires adjuvant chemotherapy because of its high recurrence rate. Previous randomized controlled trials showed that oxaliplatin (OX), in addition to fluorinated pyrimidine-based therapy for patients with stage II/III CC, significantly improves cancer survival but it remains controversial as to which patient groups should receive OX-containing regimens. Among 1,150 consecutive patients who underwent curative resection for stage II/III CC between 2009 and 2016 at two tertiary hospitals, 349 patients treated with only peroral (PO) fluorinated pyrimidine-based chemotherapy and 149 patients who received fluorinated pyrimidine-based chemotherapy with OX as adjuvant chemotherapy were retrospectively reviewed. The primary outcome was recurrence-free survival (RFS). Clinicopathological factors were more advanced in patients treated with OX than in patients treated only with PO fluorinated pyrimidine agents. Multivariate analysis for 5-year RFS showed that T4 [hazard ratio (HR), 2.947; P=0.0001], N2 (HR, 2.704; P=0.0075), vessel or lymphatic invasion (HR, 1.675; P=0.0437) and high cancer antigen (CA)19-9 (HR 3.367, P=0.0002) levels were independent risk factors of cancer relapse. Propensity score matching analysis was performed to match clinicopathological differences between the PO and OX groups. After matching, subgroup analysis of the patients showed that greater effects of OX on cancer survival were observed in patients in the OX group with high CA19-9 levels and tended to be associated with T4 and N2 compared with the PO group. Thus, OX-containing regimens should be recommended for patients with CC with these factors in an adjuvant setting.

Correction to: Intramural metastasis to the appendix from ascending colon cancer: a case report.

In the original publication of this article [1], an author's name should be changed from Shin Takasue to Shin Takesue.

Intramural metastasis to the appendix from ascending colon cancer: a case report.

BACKGROUND: Intramural metastasis is rare in colorectal cancer, especially metastasis of ascending colon cancer to the appendix. CASE PRESENTATION: A 64-year-old man was admitted to our hospital for surgery for ascending colon cancer detected by medical examination. Colonoscopy identified a type-2 tumor in the ascending colon, which was diagnosed as adenocarcinoma. Abdominal computed tomography revealed focal thickening of the ascending colon and middle of the appendix and swelling of the lymph nodes around the ileocolic artery. The patient underwent laparoscopic right hemi-colectomy with D3 lymph node dissection. Histopathological findings revealed that the ascending colon cancer was moderately differentiated adenocarcinoma with lymphatic and vascular invasion (stage IIIB; pT3N2M0). Additionally, moderately differentiated adenocarcinoma was observed mainly in the submucosa and muscularis propria of the appendix, which was approximately 10 cm proximal to the ascending colon cancer. These findings indicated intramural metastasis to the appendix from the ascending colon cancer. The patient experienced recurrence with lung metastasis 2.5 years after the first surgery. CONCLUSIONS: Intramural metastasis of ascending colon cancer to the appendix is extremely rare. Because the risk of recurrence and the prognosis for intramural metastasis has not been clarified, careful follow-up is recommended.

Pancreatic stellate cells reorganize matrix components and lead pancreatic cancer invasion via the function of Endo180.

Specific cell populations leading the local invasion of cancer are called "leading cells". However, the underlying mechanisms are unclear. Here, we identified leading cells in pancreatic cancer and determined how these cells lead and promote cancer cell invasion in the extracellular matrix (ECM). Using three-dimensional matrix remodeling assay, we found that pancreatic stellate cells (PSCs) frequently invaded the collagen matrix with pancreatic cancer cells (PCCs), which invaded behind the invading PSCs. In addition, invading PSCs changed the alignment of collagen fibers, resulting in ECM remodeling and an increase in the parallel fibers along the direction of invading PSCs. Endo180 expression was higher in PSCs than in PCCs, Endo180 knockdown in PSCs attenuated the invasive abilities of PSCs and co-cultured PCCs, and decreased the expression level of phosphorylated myosin light chain 2 (MLC2). In mouse models, Endo180-knockdown PSCs suppressed tumor growth and changes in collagen fiber orientation in co-transplantation with PCCs. Our findings suggest that PSCs lead the local invasion of PCCs by physically remodeling the ECM, possibly via the function of Endo180, which reconstructs the actin cell skeleton by phosphorylation of MLC2.

Cancer-associated peritoneal mesothelial cells lead the formation of pancreatic cancer peritoneal dissemination.

The interaction between the cancer cells and the peritoneal mesothelial cells (PMCs) plays an important role in the peritoneal dissemination in several types of cancer. However, the role of PMCs in the peritoneal dissemination of pancreatic cancer remains unclear. In the present study, we investigated the interaction between the pancreatic cancer cells (PCCs) and the PMCs in the formation of peritoneal dissemination in vitro and in vivo. The tumor-stromal interaction of PCCs and PMCs significantly enhanced their mobility and invasiveness and enhanced the proliferation and anoikis resistance of PCCs. In a 3D organotypic culture model of peritoneal dissemination, co-culture of PCCs and PMCs significantly increased the cells invading into the collagen gel layer compared with mono-culture of PCCs. PMCs pre-invaded into the collagen gel, remodeled collagen fibers, and increased parallel fiber orientation along the direction of cell invasion. In the tissues of peritoneal dissemination of the KPC (LSL-KrasG12D/+; LSL-Trp53R172H/+;Pdx-1-Cre) transgenic mouse, the monolayer of PMCs was preserved in tumor-free areas, whereas PMCs around the invasive front of peritoneal dissemination proliferated and invaded into the muscle layer. In vivo, intraperitoneal injection of PCCs with PMCs significantly promoted peritoneal dissemination compared with PCCs alone. The present data suggest that the cancer-associated PMCs have important promoting roles in the peritoneal dissemination of PCCs. Therapy targeting cancer-associated PMCs may improve the prognosis of patients with pancreatic cancer.

Extra-pancreatic invasion induces lipolytic and fibrotic changes in the adipose microenvironment, with released fatty acids enhancing the invasiveness of pancreatic cancer cells.

Pancreatic cancer progression involves components of the tumor microenvironment, including stellate cells, immune cells, endothelial cells, and the extracellular matrix. Although peripancreatic fat is the main stromal component involved in extra-pancreatic invasion, its roles in local invasion and metastasis of pancreatic cancer remain unclear. This study investigated the role of adipose tissue in pancreatic cancer progression using genetically engineered mice (Pdx1-Cre; LSL-KrasG12D; Trp53R172H/+) and an in vitro model of organotypic fat invasion. Mice fed a high fat diet had significantly larger primary pancreatic tumors and a significantly higher rate of distant organ metastasis than mice fed a standard diet. In the organotypic fat invasion model, pancreatic cancer cell clusters were smaller and more elongated in shape and showed increased fibrosis. Adipose tissue-derived conditioned medium enhanced pancreatic cancer cell invasiveness and gemcitabine resistance, as well as inducing morphologic changes in cancer cells and increasing the numbers of lipid droplets in their cytoplasm. The concentrations of oleic, palmitoleic, and linoleic acids were higher in adipose tissue-derived conditioned medium than in normal medium, with these fatty acids significantly enhancing the migration of cancer cells. Mature adipocytes were smaller and the concentration of fatty acids in the medium higher when these cells were co-cultured with cancer cells. These findings indicate that lipolytic and fibrotic changes in peripancreatic adipose tissue enhance local invasiveness and metastasis via adipocyte-released fatty acids. Inhibition of fatty acid uptake by cancer cells may be a novel therapy targeting interactions between cancer and stromal cells.

Suppression of CD51 in pancreatic stellate cells inhibits tumor growth by reducing stroma and altering tumor-stromal interaction in pancreatic cancer.

Pancreatic stellate cells (PSCs) enhance the malignant behavior of pancreatic cancer by interacting with cancer cells and producing extracellular matrix (ECM). To date, several stroma-targeted therapies for pancreatic cancer have been attempted, but these therapies are still not in practical use. Integrins expressed in stromal cells are involved in fibrosis of several organs, as well as promoting tumor malignancy. We investigated whether CD51, also known as integrin αV, expressed in PSCs was associated with stromal formation of pancreatic cancer and enhancement of tumor malignancy. We also assessed the effects of suppression of CD51 in PSCs on pancreatic cancer. Immunohistochemistry for CD51 in resected pancreatic cancer tissues showed that high expression of CD51 in the tumor stroma was associated with lymph node metastasis (P=0.025), positive pathologic margin (P=0.025), and shorter patient survival times (P=0.043). Lentivirus-mediated short hairpin RNA knockdown of CD51 decreased the proliferation and migration of PSCs. Quantitative real-time polymerase chain reaction showed that expression levels of genes related with ECM and tumor-stromal interactions were decreased by CD51 knockdown in PSCs. In a co-implantation model of pancreatic cancer cells and PSCs, tumor growth in vivo was inhibited by CD51 knockdown in PSCs (P<0.05). We also found reduced tumor stroma and decreased proliferation of cancer cells in implanted cancer tissues with CD51-silenced PSCs (P<0.05). Our results showed that CD51 expression in pancreatic cancer stroma is associated with enhanced tumor malignancy and that CD51 may be a potential therapeutic target for pancreatic cancer.

Hypoxic stellate cells of pancreatic cancer stroma regulate extracellular matrix fiber organization and cancer cell motility.

Desmoplasia and hypoxia in pancreatic cancer mutually affect each other and create a tumor-supportive microenvironment. Here, we show that microenvironment remodeling by hypoxic pancreatic stellate cells (PSCs) promotes cancer cell motility through alteration of extracellular matrix (ECM) fiber architecture. Three-dimensional (3-D) matrices derived from PSCs under hypoxia exhibited highly organized parallel-patterned matrix fibers compared with 3-D matrices derived from PSCs under normoxia, and promoted cancer cell motility by inducing directional migration of cancer cells due to the parallel fiber architecture. Microarray analysis revealed that procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2) in PSCs was the gene that potentially regulates ECM fiber architecture under hypoxia. Stromal PLOD2 expression in surgical specimens of pancreatic cancer was confirmed by immunohistochemistry. RNA interference-mediated knockdown of PLOD2 in PSCs blocked parallel fiber architecture of 3-D matrices, leading to decreased directional migration of cancer cells within the matrices. In conclusion, these findings indicate that hypoxia-induced PLOD2 expression in PSCs creates a permissive microenvironment for migration of cancer cells through architectural regulation of stromal ECM in pancreatic cancer.

CD166/ALCAM expression is characteristic of tumorigenicity and invasive and migratory activities of pancreatic cancer cells.

BACKGROUND: CD166, also known as activated leukocyte cell adhesion molecule (ALCAM), is expressed by various cells in several tissues including cancer. However, the role of CD166 in malignant tumors is controversial, especially in pancreatic cancer. This study aimed to clarify the role and significance of CD166 expression in pancreatic cancer. METHODS: We performed immunohistochemistry and flow cytometry to analyze the expression of CD166 in surgical pancreatic tissues and pancreatic cancer cell lines. The differences between isolated CD166+ and CD166- pancreatic cancer cells were analyzed by invasion and migration assays, and in mouse xenograft models. We also performed quantitative RT-PCR and microarray analyses to evaluate the expression levels of CD166 and related genes in cultured cells. RESULTS: Immunohistochemistry revealed high expression of CD166 in pancreatic cancer tissues (12.2%; 12/98) compared with that in normal pancreas controls (0%; 0/17) (p = 0.0435). Flow cytometry indicated that CD166 was expressed in 33.8-70.2% of cells in surgical pancreatic tissues and 0-99.5% of pancreatic cancer cell lines. Invasion and migration assays demonstrated that CD166- pancreatic cancer cells showed stronger invasive and migratory activities than those of CD166+ cancer cells (p<0.05). On the other hand, CD166+ Panc-1 cells showed a significantly stronger colony formation activity than that of CD166- Panc-1 cells (p<0.05). In vivo analysis revealed that CD166+ cells elicited significantly greater tumor growth than that of CD166- cells (p<0.05) in both subcutaneous and orthotopic mouse tumor models. mRNA expression of the epithelial-mesenchymal transition activator Zeb1 was over-expressed in CD166- cells (p<0.001). Microarray analysis showed that TSPAN8 and BST2 were over-expressed in CD166+ cells, while BMP7 and Col6A1 were over-expressed in CD166- cells. CONCLUSIONS: CD166+ pancreatic cancer cells are strongly tumorigenic, while CD166- pancreatic cancer cells exhibit comparatively stronger invasive and migratory activities. These findings suggest that CD166 expression is related to different functions in pancreatic cancer cells.