Risk factors for non-reaching of ileal pouch to the anus in laparoscopic restorative proctocolectomy with handsewn anastomosis for ulcerative colitis

Background/Aims

Restorative proctocolectomy (RPC) with ileal pouch-anal anastomosis and handsewn anastomosis for ulcerative colitis requires pulling down of the ileal pouch into the pelvis, which can be technically challenging. We examined risk factors for the pouch not reaching the anus.

Methods

Clinical records of 62 consecutive patients who were scheduled to undergo RPC with handsewn anastomosis at the University of Tokyo Hospital during 1989–2019 were reviewed. Risk factors for non-reaching were analyzed in patients in whom hand sewing was abandoned for stapled anastomosis because of non-reaching. Risk factors for non-reaching in laparoscopic RPC were separately analyzed. Anatomical indicators obtained from presurgical computed tomography (CT) were also evaluated.

Results

Thirty-seven of 62 cases underwent laparoscopic procedures. In 6 cases (9.7%), handsewn anastomosis was changed to stapled anastomosis because of non-reaching. Male sex and a laparoscopic approach were independent risk factors of non-reaching. Distance between the terminal of the superior mesenteric artery (SMA) ileal branch and the anus > 11 cm was a risk factor for non-reaching.

Conclusions

Laparoscopic RPC with handsewn anastomosis may limit extension and induction of the ileal pouch into the anus. Preoperative CT measurement from the terminal SMA to the anus may be useful for predicting non-reaching.

Clinical significance of CD8+ and FoxP3+ tumor-infiltrating lymphocytes and MFG-E8 expression in lower rectal cancer with preoperative chemoradiotherapy

Preoperative chemoradiotherapy (CRT) for rectal cancer contributes to tumor down-staging and decreases locoregional recurrence. However, each patient shows a significantly different response to CRT. Therefore, the identification of predictive factors to CRT response would be beneficial to avoid unnecessary treatment. Cancer immunity in patients has been suggested to play an important role in the eradication of the tumor by CRT. In the present study, the utility of CD8⁺ and forkhead box P3 (FoxP3)⁺ tumor-infiltrating lymphocytes (TILs) and the expression of a novel immuno-regulatory factor, lactadherin (MFG-E8), in predicting CRT effectiveness in patients with rectal cancer was examined. A total of 61 patients with rectal cancer, who underwent curative resection following CRT were included in the study. The numbers of CD8⁺ and FoxP3⁺ TILs in a biopsy taken before CRT and MFG-E8 expression level in the specimens obtained at the time of the surgery after CRT were examined using immunohistochemical staining, and their association with clinicopathological characteristics, including patient survival, was determined. The tumors with more CD8⁺ TILs in the biopsy samples before CRT showed a significantly more favorable CRT response. The patients with tumors and a higher number of CD8⁺ TILs before CRT also exhibited significantly longer disease-free and overall survival times. Higher MFG-E8 expression level in post-CRT specimens was significantly associated with favorable CRT response; however, no significant association was found with any other clinicopathological characteristics, including survival time. The number of CD8⁺ TILs before CRT was a valuable predictor for CRT response and was associated with favorable prognosis in patients with lower rectal cancer and who were treated with CRT. High MFG-E8 expression level after CRT was also associated with a favorable CRT response.

Establishment of deformable three-dimensional printed models for laparoscopic right hemicolectomy in transverse colon cancer

BACKGROUND

Applications of three-dimensional (3-D) printed solid organ models for navigation and simulation were previously reported for abdominal surgeries, and their usefulness was shown by subjective evaluation. However, thus far, no study has examined the effect of intraoperative movements for tissue handling. Novel, deformable 3-D printed models of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) were created to optimize laparoscopic right hemicolectomy. The aim of this study was to establish a method using these individualized models for use in surgical practice.

METHODS

Deformable 3-D models for laparoscopic right hemicolectomy were created using a 3-D printing flexible filamentous material (thermoplastic polyurethane). Five patients with transverse colon cancer who underwent laparoscopic right hemicolectomy with D3 lymphadenectomy between April 2017 and September 2019 were enrolled in this study. Then, the created patient-specific models were compared with the previously recorded intraoperative video views.

RESULTS

Transverse colon mobilization changed the spatial arrangement of the branches of the SMA and SMV. The 3-D models reproduced the intraoperative view, although approaches to the dominant vessels to complete D3 lymphadenectomy may vary.

CONCLUSIONS

Deformable 3-D models of the SMA and SMV with added branches may aid in optimizing laparoscopic right hemicolectomy operations.

Change in skeletal muscle index and its prognostic significance in conversion therapy for initially unresectable colorectal cancer

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Background: Systemic chemotherapy can cause loss of skeletal muscle mass in colorectal cancer (CRC) patients in the neoadjuvant and palliative settings. However, it is largely unknown how the body composition is changed by chemotherapy rendering unresectable CRC to resectable disease or how it affects the prognosis. This study aimed at elucidating the effects of systemic chemotherapy on skeletal muscles and survival in stage IV CRC patients who underwent conversion therapy. Methods: We reviewed 98 stage IV CRC patients who received systemic chemotherapy in our hospital. According to the treatment setting, patients were divided into the ‘Conversion’, ‘Neoadjuvant chemotherapy (NAC)’, and ‘Palliation’ groups. The cross-sectional area of skeletal muscles at the third lumbar level and changes in the skeletal muscle index (SMI), defined as the area divided by height squared, during chemotherapy were compared among patient groups. The effects of these parameters on prognosis were analyzed in the Conversion group. Results: The mean SMI increased by 8.0% during chemotherapy in the Conversion group (n = 38), whereas it decreased by 6.2% in the NAC group (n = 18) and 3.7% in the Palliation group (n = 42, p < 0.0001). Moreover, patients with increased SMI during chemotherapy had a better overall survival (OS) than those whose SMI decreased in the Conversion group (p = 0.021). The increase in SMI was an independent predictor of favorable OS on multivariate analysis (hazard ratio: 0.26). Conclusions: Stage IV CRC patients who underwent conversion to resection often had an increased SMI. As such an increase in SMI further conveys a survival benefit in conversion therapy, it may be important to make efforts to preserve muscle mass by meticulous approaches, such as nutritional support, muscle exercise programs, and pharmacological intervention even during chemotherapy in patients with metastatic CRC.

Utility of computed tomography and 18 F-fluorodeoxyglucose with positron emission tomography/computed tomography for distinguishing appendiceal mucocele caused by mucinous adenocarcinoma from other pathologies

AIM

Differentiating appendiceal mucocele with mucinous adenocarcinoma from other pathologies before surgery is difficult. The objective of this study was to evaluate the utility of CT and ¹⁸ F-fluorodeoxyglucose (FDG) with positron emission tomography (PET)/CT for differentiating mucinous adenocarcinoma of appendiceal mucocele from other pathologies.

METHOD

The study included 25 patients who underwent surgery for clinically diagnosed appendiceal mucoceles detected on CT at the University of Tokyo Hospital. Among these patients, 19 underwent FDG-PET/CT preoperatively. We compared features of the CT imaging findings and maximum standard uptake values (SUV_max ) detected by FDG-PET/CT between mucocele with mucinous adenocarcinoma and other pathologies.

RESULTS

A total of 13 men (52%) and 12 women (48%) were included in this study, with a median age of 65 years (range 34-83). There were six patients (24%) with pathologically confirmed mucinous adenocarcinoma, 15 patients (60%) with appendiceal mucinous neoplasm and four patients (16%) with simple mucocele caused by chronic inflammation. On the CT findings, wall irregularity was the only significant feature for the two groups in this study (83.3% vs 0.0%, P < 0.01). There was a significant difference in the SUV_max levels on PET/CT between the two groups (100.0% vs 20.0%, P < 0.01).

CONCLUSION

Distinguishing between mucocele with mucinous adenocarcinoma and other pathologies using imaging modalities is challenging. Our results suggest that wall irregularity on CT and elevated SUV_max on PET/CT are useful factors that can be employed for such discrimination.

Change in skeletal muscle index and its prognostic significance in patients who underwent successful conversion therapy for initially unresectable colorectal cancer: observational study

BACKGROUND

Systemic therapy can cause loss of skeletal muscle mass in colorectal cancer (CRC) patients in the neoadjuvant and palliative settings. However, it is unknown how the body composition is changed by chemotherapy rendering unresectable CRC to resectable disease or how it affects the prognosis. This study aimed at elucidating the effects of systemic therapy on skeletal muscles and survival in stage IV CRC patients who underwent conversion therapy.

METHODS

We reviewed 98 stage IV CRC patients who received systemic therapy in our hospital. According to the treatment setting, patients were divided into the conversion, neoadjuvant chemotherapy (NAC), and palliation groups. The cross-sectional area of skeletal muscles at the third lumbar level and changes in the skeletal muscle index (SMI), defined as the area divided by height squared, during systemic therapy were compared among patient groups. The effects of these parameters on prognosis were analyzed in the conversion group.

RESULTS

The mean SMI increased by 9.4% during systemic therapy in the conversion group (n = 38), whereas it decreased by 5.9% in the NAC group (n = 18) and 3.7% in the palliation group (n = 42, p < 0.0001). Moreover, patients with increased SMI during systemic therapy had a better overall survival (OS) than those whose SMI decreased in the conversion group (p = 0.025). The increase in SMI was an independent predictor of favorable OS on multivariate analysis (hazard ratio 0.25).

CONCLUSIONS

Stage IV CRC patients who underwent conversion to resection often had an increased SMI. On the other hand, a decrease in the SMI during systemic therapy was a negative prognostic factor in such patients.

Effects of preceding endoscopic treatment on laparoscopic surgery for early rectal cancer

AIM

Endoscopic treatment for rectal cancer, such as endoscopic mucosal resection and endoscopic submucosal dissection, causes inflammation, oedema and fibrosis in the surrounding tissue. However, little is known about the effect of these endoscopic therapies on salvage laparoscopic rectal surgery. The objective of this retrospective cohort study was to analyse the effect of preceding endoscopic treatment on the outcomes of laparoscopic surgery for rectal cancer.

METHOD

We analysed 53 patients who underwent laparoscopic surgery for rectal cancer with clinical Tis or T1 at our department between May 2011 and June 2019. Data from 30 patients who underwent laparoscopic surgery after preceding endoscopic treatment (Group E + S) were compared with those of 23 patients who underwent laparoscopic surgery alone (Group S).

RESULTS

There was no significant difference between the groups with respect to preoperative details. The mean operative time tended to be longer in Group E + S, and the volume of intra-operative blood loss was greater in Group E + S than in Group S (median 63 ml vs 10 ml, P = 0.049). There were no significant differences between the groups in other surgical parameters or oncological outcomes.

CONCLUSION

Laparoscopic surgery after endoscopic treatment for rectal cancer may be difficult due to an increased risk of intra-operative bleeding. Long-term prognosis after surgery was not affected by preceding endoscopic treatment in rectal cancer.

Anastomotic bleeding following ileocolic end-to-side anastomosis using a circular stapler: incidence and risk factors

PURPOSE

To identify the incidence of and risk factors for postoperative bleeding after ileocolic end-to-side anastomosis using a circular stapler.

METHODS

We analyzed, retrospectively, the risk factors for postoperative anastomotic bleeding in patients who underwent right-sided colectomy with end-to-side anastomosis done using a circular stapler during colon tumor surgery at our institute between January 2015 and March 2019.

RESULTS

Anastomotic bleeding developed in 10 (3.6%) of the total 279 patients. Univariate analysis revealed that age ≥ 80 years (8.8% vs. 1.9%; P = 0.008) and Eastern Cooperative Oncology Group performance status (ECOG PS) ≥ 1 (12.5% vs. 2.8%; P = 0.014) were significant risk factors for anastomotic bleeding. Postoperative anticoagulation therapy was not a risk factor for anastomotic bleeding. Multivariate analysis revealed that only age ≥ 80 years was an independent risk factor (odds ratio 4.12, 95% confidence interval 1.02-16.68, P = 0.047). Six of the ten patients with anastomotic bleeding were treated conservatively, three were treated by colonoscopic clipping, and one required surgery.

CONCLUSION

End-to-side anastomosis is safe and feasible, but must be performed carefully in the elderly, who are at higher risk of anastomotic bleeding.

Upfront Surgery for Small Intestinal Non-Hodgkin's Lymphoma

BACKGROUND/AIM

The clinical significance of surgery for secondary small intestinal non-Hodgkin's lymphomas (NHL) remains unknown. This study aimed to investigate the efficacy of resection for both primary and secondary small intestinal NHL.

PATIENTS AND METHODS

Twenty patients with small intestinal lymphoma who underwent surgical resection at our Institute between 2009 and 2017 were retrospectively evaluated. The clinicopathological and surgery-related factors were reviewed. We also analyzed their surgical outcomes such as postoperative complications, perforation rate, and overall survival (OS).

RESULTS

In total, 13 (65%) and 7 (35%) patients had primary and secondary lymphomas, respectively. A total of 70% of patients were diagnosed with aggressive-type lymphomas. A total of 15 (75%) patients had Lugano system stage IV. Only one (5%) patient experienced postoperative grade II deep vein thrombosis and pulmonary embolism. The 3-year OS rate after surgery was 59.6%.

CONCLUSION

Surgical resection prior to chemotherapy is a feasible and safe therapeutic strategy for small intestinal NHL.

Vascular anatomy of the splenic flexure, focusing on the accessory middle colic artery and vein

AIM

Recently, the accessory middle colic artery (AMCA) has been recognized as the vessel that supplies blood to the splenic flexure. However, the positional relationship between the AMCA and inferior mesenteric vein (IMV) has not been evaluated. Herein, we aimed to evaluate the anatomy of the AMCA and the splenic flexure vein (SFV).

METHOD

Two hundred and five patients with colorectal cancer who underwent enhanced CT preoperatively were enrolled in the present study. The locations of the AMCA and IMV were evaluated, focusing on the positional relationship between the vessels and pancreas - below the pancreas or to the dorsal side of the pancreas.

RESULTS

The AMCA was observed in 74 (36.1%) patients whereas the SFV was found in 177 (86.3%) patients. The left colic artery (LCA) was the major artery accompanying the SFV in 87 (42.4%) of patients. The AMCA accompanied the SFV in 65 (32.7%) patients. In 15 (7.8%) patients, no artery accompanied the SFV. The origin of the AMCA was located on the dorsal side of the pancreas in 15 (20.3%) of these 74 patients. Similarly, the destination of the IMV was located on the dorsal side of the pancreas in 65 (31.7%) of patients.

CONCLUSION

The SFV was observed in most patients, and the LCA or AMCA was the common accompanying artery. In some patients these vessels were located on the dorsal side of the pancreas and not below it. Preoperative evaluation of this anatomy may be beneficial for lymph node dissection during left-sided hemicolectomy.

Anal canal adenocarcinoma with pagetoid spread and inguinal lymph node metastasis treated with preoperative chemoradiotherapy: A case report

Perianal Paget's disease is a rare condition, which is not usually accompanied by cancer. Here, a case of anal canal carcinoma with pagetoid spread and inguinal lymph node metastasis, which exhibited a significant response to preoperative chemoradiotherapy (CRT), is presented. A 58-year-old woman was admitted to The University of Tokyo Hospital with a complaint of discomfort around the anus. Physical examination revealed an erythematous inflamed skin lesion in the perianal region and a tumor of 15 mm in diameter detected on palpation in the left inguinal region, which was diagnosed as metastatic adenocarcinoma by excisional biopsy. Colonoscopy revealed moderately differentiated adenocarcinoma of 15 mm in diameter in the anal canal. Skin biopsy of the perianal region revealed an infiltration of pagetoid cells, which were positive for cytokeratin 7, and negative for cytokeratin 20 and gross cystic disease fluid protein 15. Based on these results, the patient was diagnosed as having anal canal adenocarcinoma with pagetoid spread. The patient received preoperative CRT including the bilateral inguinal region. After CRT, robotic-assisted laparoscopic abdominoperineal resection was performed. The macroscopic findings of the surgical specimen confirmed the formation of a scar as a result of the preoperative CRT. Microscopic examination of the anal tumor revealed no residual carcinoma or lymph node metastasis. In conclusion, this case may suggest the potential applicability of preoperative CRT for the local control of anal canal carcinoma with pagetoid spread.

Metastatic role of mammalian target of rapamycin signaling activation by chemoradiotherapy in advanced rectal cancer

Postoperative distant metastasis dramatically affects rectal cancer patients who have undergone neoadjuvant chemoradiotherapy (NACRT). Here, we clarified the association between NACRT‐mediated mammalian target of rapamycin (mTOR) signaling pathway activation and rectal cancer metastatic potential. We performed immunohistochemistry for phosphorylated mTOR (p‐mTOR) and phosphorylated S6 (p‐S6) on surgical specimen blocks from 98 rectal cancer patients after NACRT (cohort 1) and 80 colorectal cancer patients without NACRT (cohort 2). In addition, we investigated the association between mTOR pathway activity, affected by irradiation, and the migration ability of colorectal cancer cells in vitro. Based on the results of the clinical study, p‐mTOR was significantly overexpressed in cohort 1 (with NACRT) as compared to levels in cohort 2 (without NACRT) (P < .001). High p‐mTOR and p‐S6 levels correlated with the development of distant metastasis only in cohort 1. Specifically, high p‐S6 expression (HR 4.51, P = .002) and high pathological T‐stage (HR 3.73, P = .020) after NACRT were independent predictors of the development of distant metastasis. In vitro, p‐S6 levels and migration ability increased after irradiation in SW480 cells (TP53 mutation‐type) but decreased in LoVo cells (TP53 wild‐type), suggesting that irradiation modulates mTOR signaling and migration through cell type‐dependent mechanisms. We next assessed the expression level of p53 by immunostaining in cohort 1 and demonstrated that p‐S6 was overexpressed in samples with high p53 expression as compared to levels in samples with low p53 expression (P = .008). In conclusion, p‐S6 levels after NACRT correlate with postoperative distant metastasis in rectal cancer patients, suggesting that chemoradiotherapy might modulate the mTOR signaling pathway, promoting metastasis.

Incidence of and risk factors for lymphocele formation after lateral pelvic lymph node dissection for rectal cancer: a retrospective study

AIM

Pelvic lymphocele is a common complication that develops after pelvic lymph node dissection. The incidence of pelvic lymphocele formation has been reported to be 10.5-51% after gynaecological or urological procedures. However, no evidence has been reported thus far with regard to the development of pelvic lymphocele following lateral pelvic lymph node dissection (LPND) for low rectal cancer. The aim of this study was to investigate the incidence of and risk factors for lymphocele formation after LPND for low rectal cancer and to examine its clinical management.

METHOD

We retrospectively analysed the incidence of and risk factors for pelvic lymphocele formation after LPND for rectal cancer in our hospital between January 2012 and December 2017. We also compared the size of the lymphocele between asymptomatic and symptomatic patients by using CT volumetry and examined its clinical management.

RESULTS

A total of 30 out of 98 patients (30.8%) developed pelvic lymphocele after rectal LPND. The number of resected nodes was significantly higher in patients with a pelvic lymphocele (P < 0.01). The median volume was significantly higher in patients with symptomatic pelvic lymphocele (P = 0.011). Among the nine symptomatic patients, two underwent CT-guided drainage, one underwent transurethral ureteral stent placement and one underwent laparoscopic marsupialization.

CONCLUSION

It is essential to keep in mind the possibility of pelvic lymphocele formation during follow-up of patients who undergo LPND, and to consider an appropriate treatment when these patients are symptomatic.

Assessment of the Changes in Mitochondrial Gene Polymorphism in Ulcerative Colitis and the Etiology of Ulcerative Colitis-associated Colorectal Cancer

BACKGROUND

Mitochondria are energy-producing organelles, and dysfunction in these organelles causes various types of disease. Although several studies have identified mutations in nuclear DNA that are associated with the etiology of ulcerative colitis (UC), information regarding mitochondrial DNA (mtDNA) in UC is limited. This study aimed to investigate the mitochondrial DNA polymorphism underlying the etiology of UC and UC-associated colorectal cancer.

MATERIALS AND METHODS

Next-generation sequencing was performed to assess mitochondrial DNA mutations in 12 patients with UC-associated cancer. The mtDNA mutations in the non-neoplastic mucosa, tumor tissues, and healthy controls were compared.

RESULTS

The incidence of mutations of nicotinamide adenine dinucleotide phosphate ubiquinone oxidase subunit, ATP synthetase, and tRNA was higher in non-neoplastic mucosa in those with UC compared with the healthy controls. However, no statistically significant differences were observed in mutations between the tumor tissues and non-neoplastic mucosa in UC.

CONCLUSION

Significant mutations in mtDNA were observed in the non-neoplastic mucosa of patients with UC-associated cancer.

Postoperative chemotherapy is associated with prognosis of stage IV colorectal cancer treated with preoperative chemotherapy/chemoradiotherapy and curative resection

PURPOSE

Advances in systemic chemotherapy have increased the resectability in colorectal cancer (CRC) associated with metastases even if it was initially unresectable. However, what determines the prognosis of stage IV CRC patients treated by preoperative therapy and surgery remains unclear. We attempted to identify prognostic factors in such CRC patients.

METHODS

We reviewed stage IV CRC patients who underwent curative resection between December 2007 and May 2019. The patients who underwent conversion chemotherapy for initially unresectable disease and those who received neoadjuvant chemotherapy (NAC) for resectable synchronous metastases or neoadjuvant chemoradiotherapy (NACRT) for advanced lower rectal cancer with resectable metastases were included. Recurrence-free survival (RFS) and overall survival (OS) were examined by multivariate analyses using Cox proportional hazard models. The RFS and OS curves were analyzed according to postoperative adjuvant chemotherapy (AC).

RESULTS

Among 70 patients who underwent curative surgery (34 men, mean age: 60 years old), 33 had initially unresectable disease, 23 received NAC, and 14 NACRT. By multivariate analyses, AC was an independent predictor for improved RFS and OS (hazard ratio = 0.29, p = 0.0002, and hazard ratio = 0.37, p = 0.025). Patients treated with AC showed improved RFS and OS than those without AC (2-year RFS rate = 30% vs 19%, p = 0.031, and 3-year OS rate = 87% vs 67%, p = 0.045).

CONCLUSION

Because of its association with improved prognosis, AC should be considered for stage IV CRC patients after curative resection regardless of initial resectability status and preoperative therapy.

Risk factors and therapeutic significance for inguinal lymph node metastasis in advanced lower rectal cancer

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Background: Which patients with lower rectal cancer are at risk of inguinal lymph node metastasis (ILNM) and how to treat ILNM remain unclear. This study aimed to clarify the predictors of ILNM and clinical significance of treatment for ILNM. Methods: Consecutive patients with rectal adenocarcinoma invading the anal canal who underwent curative surgery between 2003 and 2019 at a single institution were retrospectively reviewed. The pathological nodal involvement in mesorectal, lateral pelvic or inguinal lymph nodes (ILN) at the time of rectal surgery and of later onset were collectively defined as final nodal metastasis (f-LNM) in this study. Factors associated with f-LNM were analyzed. Moreover, the ‘modified therapeutic value index’ defined by the 5-year overall survival rate of patients treated against f-LNM multiplied by their frequency was calculated for each lymph node area. Results: A total of 145 patients were enrolled, among whom16 patients developed ILNM. For predicting f-ILNM, the cutoff 8.5 mm of ILN diameter gave area under the curve of 0.889. Dentate line involvement and ILN larger than a simplified cutoff of 8 mm were independently associated with the development of ILNM (odds ratio: 33.4 and 11.9, respectively). The modified therapeutic value indice of inguinal, lateral pelvic and mesorectal LNs in the entire population were 6.1, 8.2 and 20.3 points, respectively. In patients with dentate line invaded by cancer, they were 11.7, 5.8 and 16.2 points, respectively. Moreover, the index of ILN was 21.1 points when confined to patients with ILN larger than 8 mm. Conclusions: Dentate line involvement and ILN larger than 8 mm were predictive of developing ILNM in patients with rectal cancer invading the anal canal. Treatment of ILNM may be recommended for patients manifesting the above predictors, given the significant therapeutic outcomes.

Accelerated perineural invasion in colitis-associated cancer: A retrospective cohort study

Perineural invasion (PNI) is a prognostic factor in patients with colorectal cancer. Neurotrophic factors, molecular determinants of PNI, are altered in their expression levels in patients with ulcerative colitis. In this study, we evaluated the frequency of PNI in colitis-associated cancer (CAC) and sporadic cancer.We retrospectively reviewed 778 colorectal cancers with pathological T3-T4 in 761 patients all of whom were surgically resected without preoperative treatment. The lesions were classified into either CAC or sporadic cancer based on the clinical information. Clinicopathological findings including PNI were compared between CACs and sporadic cancers. Moreover, we analyzed the risk factors for positive PNI by multivariate analysis using a logistic regression model.Ten of the cancers (1.3%) were diagnosed as CACs, and the remaining 768 as sporadic cancers. CACs were characterized by being nonobstructive and predominantly located in the rectum. The CACs had a larger size and more frequent undifferentiated histology than sporadic cancers. PNI was observed more frequently in CACs (90%) than in sporadic cancers without obstruction (45%, P = .007). On multivariate analysis, CAC was one of the significant factors associated with PNI (odds ratio: 9.05, P = .040).Our results suggest that CAC was more likely to exhibit PNI than sporadic colorectal cancer.

Management of isolated para-aortic lymph node recurrence of colorectal cancer

Isolated para-aortic lymph node recurrence (PALNR) after curative surgery for colorectal cancer (CRC) is rare and its optimal management is not defined clearly. This review investigates the best outcomes among published studies on the management of PALNR in the field of CRC. We searched the PubMed database for studies reporting on the management of isolated PALNR in CRC, published in English or Japanese from January, 2000 to December, 2018. Studies including patients with other metastases were excluded. A total of 24 retrospective studies including 227 patients with PALNR were evaluated. The 3-year overall survival (OS) ranged from 60 to 100%, with a median OS of 34-80 months for patients who underwent PALNR dissection, and 14-42 months for patients who received non-surgical treatment. No surgery-related mortality was reported and the incidence of surgical, mainly low-grade, complications ranged from 33 to 52%. The predictors of improved survival outcome included R0 resection margins. Dissection for PALNR from CRC is considered a feasible treatment option that may yield a better prognosis than non-surgical treatment alone. Preoperative chemotherapy or CRT should be considered for their potential benefits, including a reduction in cancer volume and improved R0 resection rates.

The influence of pulmonary comorbidities on treatment choice and short-term surgical outcomes among elderly patients with colorectal cancer

PURPOSE

Most elderly patients with colorectal cancer have comorbidities and reduced functional reserve, which may increase their risks of postoperative morbidity and mortality, and subsequently influence the treatment choice. Therefore, this study aimed to investigate the treatment choice and compare laparoscopic and open surgery in this setting.

METHODS

This retrospective study evaluated 118 patients with colorectal cancer (≥ 85 years old between January 2007 and February 2018) to determine the influence of comorbidities on treatment choice, as well as the safety and feasibility of laparoscopic surgery for these patients.

RESULTS

The patients included 42 men (35.6%) and 106 patients (89.8%) with comorbidities. The treatments were curative resection for 90 patients and palliative surgery for 16 patients, including 5 cases of colostomy/ileostomy because of the difficulty of primary cancer resection, pneumonia, or pulmonary hypertension. Twelve patients received non-surgical treatment, including 7 patients with decreased respiratory function because of chronic obstructive pulmonary disease or pneumonia. Forty-three patients underwent open curative resection and 47 patients underwent laparoscopic curative resection, which was associated with a significantly shorter hospital stay (14 days vs. 19days, P < 0.01), a lower morbidity rate (17.0% vs. 37.2%, P = 0.035), and less blood loss (10 mL vs. 140 mL, P < 0.01). One patient in each group died during the postoperative period because of worsened pre-existing pneumonia.

CONCLUSION

Laparoscopic surgery was safer and less invasive than open surgery for colorectal cancer among ≥ 85-year-old patients. Pulmonary comorbidities affected the choice of non-curative surgery and may be related to the risk of postoperative mortality.

Obstruction is associated with perineural invasion in T3/T4 colon cancer

AIM

Perineural invasion (PNI) is a risk factor for recurrence and metastasis and consequently leads to decreased survival in patients with various malignancies. Recent studies showed that stent placement in obstructive colon cancer increases the frequency of PNI. We hypothesized that mechanical stress including obstruction itself may be associated with PNI.

METHOD

We retrospectively reviewed 496 patients with pathological T3 or T4 colon cancer who did not receive preoperative treatment. Data were collected from medical charts and pathological findings. The relationships between PNI and other clinicopathological factors were analysed using univariate and multivariate analyses.

RESULTS

PNI was observed in 239 (48%) patients. Obstruction was markedly more frequent in PNI-positive cancer (39%) than in PNI-negative cancer (24%, P = 0.0003). Multivariate analyses identified obstruction as one of the significant factors associated with PNI (OR 1.68, P = 0.028). Moreover, in 414 patients without distant metastasis who underwent complete resection, PNI was an independent factor associated with poor recurrence-free survival (hazard ratio 2.35, P = 0.003). The coexistence of PNI and obstruction resulted in greater decreases in recurrence-free survival than PNI-negative and/or non-obstructive cases.

CONCLUSION

Our results suggest that obstruction is associated with PNI and consequently contributes to an increased postoperative recurrence in colon cancer.

Cecal cancer with essential thrombocythemia treated by laparoscopic ileocecal resection: a case report

Background

Essential thrombocythemia (ET) is a myeloproliferative disorder characterized by thrombocytosis and a propensity for both thrombotic and hemorrhagic events. ET rarely occurs simultaneously with colorectal cancer. Here, we report a case of colorectal cancer in an ET patient treated using laparoscopic ileocecal resection.

Case presentation

A 40-year-old woman was admitted to our hospital after presenting with liver dysfunction. She had been previously diagnosed with ET; aspirin and anagrelide had been prescribed. Subsequent examination at our hospital revealed cecal cancer. Distant metastasis was absent; laparoscopic ileocecal resection was performed. Anagrelide was discontinued only on the surgery day. She was discharged on the seventh postoperative day without thrombosis or hemorrhage. However, when capecitabine and oxaliplatin were administered as adjuvant chemotherapy with continued anagrelide administration, she experienced hepatic dysfunction and thrombocytopenia; thus, anagrelide was discontinued. Five days later, her platelet count recovered. Subsequently, anagrelide and aspirin administration was resumed, without any adjuvant chemotherapy. Her liver function normalized gradually in 4 months. One-year post operation, she is well without tumor recurrence or new metastasis.

Conclusions

To our knowledge, this is the first report of laparoscopic colectomy performed on an ET patient receiving anagrelide. Our report shows that complications such as bleeding or thrombosis can be avoided by anagrelide administration. Contrastingly, thrombocytopenia due to anagrelide intake should be considered when chemotherapy that could cause bone marrow suppression is administered.

The component changes of lysophospholipid mediators in colorectal cancer

Although lysophospholipids are known to play an important role in the development and progression of several kinds of cancers, their role in human colorectal cancer is as yet unclear. In this study, we aim to investigate lysophospholipid levels in colorectal cancer tissues to identify lysophospholipids, the levels of which change specifically in colorectal cancers. We used liquid chromatography-tandem mass spectrometry to measure lysophospholipid levels in cancerous and normal tissues from 11 surgical specimens of sigmoid colon cancers, since recent advances in this field have improved detection sensitivities for lysophospholipids. Our results indicate that, in colon cancer tissues, levels of lysophosphatidylinositol and lysophosphatidylserine were significantly higher ( p = 0.025 and p = 0.01, respectively), whereas levels of lysophosphatidic acid were significantly lower ( p = 0.0019) than in normal tissues. Although levels of lysophosphatidylglycerol were higher in colon cancer tissues than in normal tissues, this difference was not found to be significant ( p = 0.11). Fatty acid analysis further showed that 18:0 lysophosphatidylinositol and 18:0 lysophosphatidylserine were the predominant species of lysophospholipids in colon cancer tissues. These components may be potentially involved in colorectal carcinogenesis.

Molecular Subtypes Are Frequently Discordant Between Lesions in Patients With Synchronous Colorectal Cancer: Molecular Analysis of 59 Patients

BACKGROUND

We aimed to investigate the molecular features of synchronous colorectal cancer (CRC).

MATERIALS AND METHODS

Out of 1,262 patients with CRC, 130 lesions in 59 patients with synchronous CRC were retrospectively analyzed. Microsatellite, v-Ki-Ras2 Kristen rat sarcoma viral oncogene homolog (KRAS), v-raf murine sarcoma viral oncogene homolog B1 (BRAF), tumor protein 53 (TP53) and β-catenin status were evaluated and compared between synchronous CRC lesions in each patient.

RESULTS

The subtypes of instability, BRAF and β-catenin subtypes was significant but low. Patients with discordant KRAS and TP53 were not concordant between lesions in the same patient, and concordance of microsatellite KRAS/BRAF subtypes comprised 50.8% of those with synchronous CRC. The rate of patients with lesions containing both mutL homolog 1 (MLH1) methylation and microsatellite stable status was 66.7% in those with synchronous CRC, with at least one lesion with high microsatellite instability.

CONCLUSION

The present study on synchronous CRC demonstrated a low concordance of molecular subtypes between lesions in the same patient. A molecular analysis of metastatic lesions is warranted for molecular targeted therapy of metastatic synchronous CRC.

Venous thromboembolism in colorectal surgery: Incidence, risk factors, and prophylaxis

Colorectal surgery is associated with a high risk of perioperative venous thromboembolism (VTE), and this risk is especially high following colorectal cancer resection and surgery for inflammatory bowel disease. Previous analyses of large databases have reported the incidence of postoperative VTE in this population to be approximately 1.1%-2.5%. Therefore, to minimize this risk, patients should be offered appropriate prophylaxis, which may involve a combination of mechanical and pharmacologic prophylaxis with low-dose unfractionated heparin or low molecular weight heparin as recommended by several guidelines. Prior to initiation of treatment, appropriate risk stratification should be performed according to the patients' basic and disease-related as well as procedure-related risk factors, and post-operative factors. Furthermore, a risk-benefit calculation that takes into account patients' VTE and bleeding risk should be performed prior to starting pharmacologic prophylaxis and to help determine the duration of treatment.

Prognostic Significance and Clinicopathological Features of Synchronous Colorectal Cancer

AIM

This study aimed to clarify the difference in the clinicopathological and prognostic features between synchronous colorectal cancer (CRC) and solitary CRC.

MATERIALS AND METHODS

A retrospective analysis was conducted in patients with synchronous and solitary CRC.

RESULTS

A total of 92 (7.1%) out of 1,295 consecutive patients had synchronous CRC. Mucinous adenocarcinoma was more frequent in patients with synchronous CRC than in those with solitary CRC (13.0% vs. 3.7%; p<0.001). The 5-year relapse-free survival (RFS) rate was poorer in patients with synchronous CRC than in those with solitary CRC (65.3% vs. 75.1%; p=0.035), which was contrived by the multivariate analysis (hazard ratio=1.52(HR); p=0.039).

CONCLUSION

Patients with synchronous CRC had a poorer RFS than those with solitary CRC; thus, patients with synchronous CRC might require more intensive care than those with solitary CRC in follow-up.

Predictors for High Microsatellite Instability in Patients with Colorectal Cancer Fulfilling the Revised Bethesda Guidelines

BACKGROUND

The revised Bethesda guidelines (rBG) are generally used for screening of Lynch syndrome, and few researchers have investigated the associations between microsatellite instability (MSI) status and each item of the rBG.

PATIENTS AND METHODS

This retrospective study included patients with colorectal cancer who were classified into those fulfilling the rBG (Bethesda group) and those not (control group). The breakdown of each item in the rBG and predictors of high MSI (MSI-H) were determined in the Bethesda group.

RESULTS

Of 809 consecutive patients, 161 (19.9%) were found to fulfil the rBG criteria. As a predictor of MSI-H, items 2 or 5 of the rBG showed a sensitivity of 93.3%. Item 5 and right-sided tumour location were independent predictors of MSI-H in patients fulfilling the rBG (odds ratio(OR)=4.49 and 25.1; p=0.0260 and <0.0001, respectively).

CONCLUSION

Item 5 of the rBG and right-sided tumour location are significant predictors of MSI-H.

Induction of IFN-λ3 as an additional effect of nucleotide, not nucleoside, analogues: a new potential target for HBV infection

OBJECTIVE

The clinical significance of polymorphisms in the interleukin-28B gene encoding interferon (IFN)-λ3, which has antiviral effects, is known in chronic HCV but not in HBV infection. Thus, we measured IFN-λ3 levels in patients with HBV and investigated its clinical significance and association with nucleos(t)ide (NUC) analogue administration.

DESIGN

Serum IFN-λ3 level was measured in 254 patients with HBV with varying clinical conditions using our own high sensitivity method. The resulting values were compared with various clinical variables. In addition, cell lines originating from various organs were cultured with NUCs, and the production of IFN-λ3 was evaluated.

RESULTS

Higher serum IFN-λ3 levels were detected in the patients treated with nucleotide analogues (adefovir or tenofovir) compared with those treated with nucleoside analogues (lamivudine or entecavir). There were no other differences in the clinical background between the two groups. A rise in the serum IFN-λ3 levels was observed during additional administration of the nucleotide analogues. In vitro experiments showed that the nucleotide analogues directly and dose-dependently induced IFN-λ3 production only in colon cancer cells. Furthermore, the supernatant from cultured adefovir-treated colon cancer cells significantly induced IFN-stimulated genes (ISGs) and inhibited hepatitis B surface antigen (HBsAg) production in hepatoma cells, as compared with the supernatant from entecavir-treated cells.

CONCLUSIONS

We discovered that the nucleotide analogues show an additional pharmacological effect by inducing IFN-λ3 production, which further induces ISGs and results in a reduction of HBsAg production. These findings provide novel insights for HBV treatment and suggest IFN-λ3 induction as a possible target.

Diagnostic performance of 18F-FDG PET/CT using point spread function reconstruction on initial staging of rectal cancer: a comparison study with conventional PET/CT and pelvic MRI

Background

Accurate staging is crucial for treatment selection and prognosis prediction in patients with rectal cancer. Point spread function (PSF) reconstruction can improve spatial resolution and signal-to-noise ratio of PET imaging. The aim of this study was to evaluate the effectiveness of ¹⁸F-FDG PET/CT with PSF reconstruction for initial staging in rectal cancer compared with conventional PET/CT and pelvic MRI.

Methods

A total of 59 patients with rectal cancer underwent preoperative ¹⁸F-FDG PET/CT and pelvic MRI. The maximum standardized uptake value (SUVmax) and lesion to background (L/B) ratio of possible metastatic lymph nodes, and metabolic tumor volumes (MTVs) of primary tumors were calculated. For N and T (T1-2 vs T3-4) staging, sensitivities, specificities, positive predictive values, negative predictive values, and accuracies were compared between conventional PET/CT [reconstructed with ordered subset expectation maximization (OSEM)], PSF-PET/CT (reconstructed with OSEM+PSF), and pelvic MRI. Histopathologic analysis was the reference standard.

Results

For N staging, PSF-PET/CT provided higher sensitivity (78.6%) than conventional PET/CT (64.3%), and pelvic MRI (57.1%), and all techniques showed high specificity (PSF-PET: 95.4%, conventional PET: 96.7%, pelvic MRI: 93.5%). SUVmax and L/B ratio were significantly higher in PSF-PET/CT than conventional-PET/CT (p < 0.001). The accuracy for T staging in PSF-PET/CT (69.4%) was not significantly different to conventional PET/CT (73.5%) and pelvic MRI (73.5%). MTVs of PSF and conventional PET showed a significant difference among T stages (p < 0.001), with higher values in advanced stages. In M staging, both PSF and conventional PET/CT diagnosed all distant metastases correctly.

Conclusions

PSF-PET/CT produced images with higher lesion-to-background contrast than conventional PET/CT, which allowed improved detection of lymph node metastasis without compromising specificity, and showed comparable diagnostic value to MRI in local staging. PSF-PET/CT is likely to have a great value for initial staging in rectal cancer.

Abstract 4528: Adiponectin receptor 2 is negatively associated with lymph node metastasis of colorectal cancer

[Background] Adiponectin is a hormone secreted by the adipose tissue. Two receptors of adiponectin, namely AdipoR1 and AdipoR2, are known, but their expression and function in tumor tissue are not yet well characterized. It is proverbial that under hypoxic condition, cancer cells acquire invasive and metastatic potentials and also resistance to therapy. Although adiponectin is reported to exert inhibitory effect on various cancer types, the regulation of AdipoRs by the hypoxic environment, nor on the effect of hypoxia on the inhibitory effect of adiponectin on cancer cells were investigated. Thus, we aimed to investigate the expression of adiponectin receptors in colorectal cancer tissues, and their clinicopathological implications. Moreover, we investigated on the mechanism underlying the regulation of AdipoRs by the hypoxic stress in colon cancer cells. [Methods] Surgically resected specimens from 48 patients with colorectal cancer, receiving surgical operation in the period between November 2008 and July 2009, were analyzed. The study was approved by the Human Ethics Committee of the University of Tokyo. The mRNA expressions of AdipoR1 and AdipoR2 were evaluated by real-time RT-PCR in cancer tissues and the matched normal counterparts. For the in vitro experiments, the human colon cancer cell line DLD-1 was cultured either under normoxia (21% O2) or hypoxia (1% O2), and the changes in the expression of AdipoRs were evaluated. Also, the effect of adiponectin on the proliferative activity of DLD-1 was assessed by the MTS assay. [Results] The mean age of the patients was 66.79±11.85 years. The levels of expression of both AdipoR1/AdipoR2 were significantly lower in cancer specimens compared with normal mucosa (0.966±0.392, vs1.366±0.408, p&lt;0.001 and 0.918±0.309 vs1.596±0.459, P&lt;0.001, respectively for AdipoR1 and AdipoR2). The mRNA levels of AdipoR1 and AdipoR2 showed a tendency of decrease in tumors with nodal metastases and the difference was significant with AdipoR2 (p&lt;0.05). Culture under hypoxia resulted in a significant upregulation of the expression levels of both adiponectin receptors on DLD-1. Also, the inhibitory effect of adiponectin on the proliferative activity of DLD-1 was potentiated under hypoxia, compared to normoxia. [Conclusion] In colorectal cancer tissue, the expression levels of both adiponectin receptors were downregulated, and the expression of AdipoR2 was associated with nodal metastases. The hypoxic environment caused up-regulation of the expression of both adiponectin receptors on colon cancer cells, consequently potentiating the inhibitory effect of adiponectin. Taking these facts, we hypothesized that, under hypoxic condition, through up-regulation of adiponectin receptor, colon cancer cells become more sensitive to adiponectin, and those cells that do not up-regulate the expression of these receptors, are more aggressive, with higher metastatic potential.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4528. doi:1538-7445.AM2012-4528

Adiponectin receptor 2 is negatively associated with lymph node metastasis of colorectal cancer

Adiponectin is a hormone secreted by adipose tissue and has a variety of functions including the inhibition of tumor growth. The expression and function of the two major adiponectin receptors, AdipoR1 and AdipoR2, in malignant tissue have not been well characterized. In the present study, we evaluated the mRNA levels of AdipoR1 and AdipoR2 expression in 48 surgically resected colorectal cancer specimens, as well as normal colonic mucosa, by quantitative RT-PCR. The values obtained were standardized by β-actin mRNA, and the correlation between their relative expression levels and the clinicopathological characteristics of the patients was examined. The relative expression levels of AdipoR1 and AdipoR2 were significantly reduced in cancer tissue compared with normal tissue (AdipoR1: 0.97±0.39 vs. 1.37±0.41, P<0.0001; AdipoR2: 0.92±0.31 vs. 1.60±0.46, P<0.0001). AdipoR1 and AdipoR2 levels were further reduced in tumors with nodal metastases and the difference was statistically significant in the case of AdipoR2 (0.79±0.27 vs. 1.02±0.30, P=0.012). The results of this study demonstrated that the expression levels of adiponectin receptors are reduced in cancer specimens compared to normal tissue, indicating a downregulation in the course of the development and progression of colorectal cancer. Since adiponectin is abundantly present in the whole body and has inhibitory effects on cancer cells, this downregulation of the receptors may be an escape mechanism of malignant cells from the suppressive effects of adiponectin.

Is surveillance endoscopy necessary after colectomy in ulcerative colitis?

The role of surveillance endoscopic followup in colectomized patients with long standing total colitis is controversial. Here, we aimed to clarify its usefulness for the early detection of dysplasia and cancer in this group of patients. Ninety-seven colectomised UC patients followedup by surveillance endoscopy were retrospectively investigated by reviewing the pathological reports. Patients had received either subtotal colectomy and ileo-rectal anastomosis (IRA) or total proctocolectomy and ileal anal anastomosis (IPAA). Definite dysplasia was diagnosed in 4 patients, who had received IRA; among them, 2 were carcinoma with submucosal invasion, and one was a high-grade dysplasia. Postoperative surveillance endoscopy is useful for the detection of early cancer in the remaining colonic mucosa of UC patients, and those receiving IRA, in which rectal mucosa is left intact, would be good candidates. However, its effectiveness for patients receiving IPAA, in which the rectal mucosa is resected, needs further investigation.

The inhibition of autophagy potentiates anti-angiogenic effects of sulforaphane by inducing apoptosis

BACKGROUND

Sulforaphane (SUL), a kind of isothiocyanate, has recently been focused due to its strong pro-apoptotic effect on cancer cells as well as tumor vascular endothelial cells (ECs). And recently, we demonstrated the induction of autophagy by colon cancer cells as a protective mechanism against SUL. In the present study, we aimed to investigate the possible role of autophagy induction by ECs as a defense mechanism against SUL.

METHODS

Human umbilical vein endothelial cells (HUVECs) were used as the in vitro model of angiogenic ECs. The induction of autophagy was evaluated by the detection of acidic vesicular organelles (AVOs) by flow-cytometry, after the staining with acridine orange, as well as the detection of light chain 3(LC3) by Western blot. Finally, the functional implication of autophagy inhibition and SUL treatment in ECs was investigated by their ability to form vascular-like structures on Matrigel.

RESULTS

Treatment of HUVECs with relatively low concentrations of SUL for 16 h resulted in the evident formation of AVOs and the recruitment of LC3 to autophagosomes, the pathognomonic features of autophagy. Co-treatment of cells with the specific autophagy inhibitor (3-methyladenine) potentiated the proapoptotic effect of SUL. And inhibition of autophagy potentiated the inhibitory effect of SUL on the ability of ECs to form capillary-like structures.

CONCLUSION

Similar to cancer cells, ECs induced autophagy in response to the pro-apoptotic agent, SUL, and the inhibition of autophagy potentiated the pro-apoptotic effect. These findings open premises for the use of autophagy inhibitors in combination with anti-angiogenic agents.

Chloroquine potentiates the anti-cancer effect of 5-fluorouracil on colon cancer cells

Background

Chloroquine (CQ), the worldwide used anti-malarial drug, has recently being focused as a potential anti-cancer agent as well as a chemosensitizer when used in combination with anti-cancer drugs. It has been shown to inhibit cell growth and/or to induce cell death in various types of cancer. 5-Fluorouracil (5-FU) is the chemotherapeutic agent of first choice in colorectal cancer, but in most cases, resistance to 5-FU develops through various mechanisms. Here, we focused on the combination of CQ as a mechanism to potentiate the inhibitory effect of 5-FU on human colon cancer cells.

Methods

HT-29 cells were treated with CQ and/or 5-FU, and their proliferative ability, apoptosis and autophagy induction effects, and the affection of the cell cycle were evaluated. The proliferative ability of HT-29 was analyzed by the MTS assay. Apoptosis was quantified by flow-cytometry after double-staining of the cells with AnnexinV/PI. The cell cycle was evaluated by flow-cytometry after staining of cells with PI. Autophagy was quantified by flow-cytometry and Western blot analysis. Finally, to evaluate the fate of the cells treated with CQ and/or 5-FU, the colony formation assay was performed.

Results

5-FU inhibited the proliferative activity of HT-29 cells, which was mostly dependent on the arrest of the cells to the G0/G1-phase but also partially on apoptosis induction, and the effect was potentiated by CQ pre-treatment. The potentiation of the inhibitory effect of 5-FU by CQ was dependent on the increase of p21^Cip1 and p27^Kip1 and the decrease of CDK2. Since CQ is reported to inhibit autophagy, the catabolic process necessary for cell survival under conditions of cell starvation or stress, which is induced by cancer cells as a protective mechanism against chemotherapeutic agents, we also analyzed the induction of autophagy in HT-29. HT-29 induced autophagy in response to 5-FU, and CQ inhibited this induction, a possible mechanism of the potentiation of the anti-cancer effect of 5-FU.

Conclusion

Our findings suggest that the combination therapy with CQ should be a novel therapeutic modality to improve efficacy of 5-FU-based chemotherapy, possibly by inhibiting autophagy-dependent resistance to chemotherapy.

Abstract 3908: Id1/Id3 Knockdown increases Chemosensitivity of Colorectal Cancer

Objective: The inhibitor of DNA binding/differentiation (Id) proteins belong to the helix-loop-helix transcriptional regulatory factors, and play important roles in tumor development. Recently, overexpression of Id-1 has been associated with more aggressive and metastatic cancers in various cancer types, as well as implicated in resistance to chemotherapy, and thus, its down-regulation has been shown to lead to increased chemotherapy-induced apoptosis. Previously, we have demonstrated that simultaneous targeting of Id1 and Id3 inhibited proliferation, migration, adhesion, and metastatic growth of colorectal cancers. In the present study, we aimed to evaluate the role of Id in chemosensitivity of colorectal cancer cells, and for this purpose, human colon cancer cells with downregulated expression of Id1/Id3 were treated with oxaliplatin, and the changes in the sensitivity to chemotherapy as well as the mechanisms underlying it were investigated.

Methods: Id1 and Id3 were stably and simultaneously knockdown in human colorectal cancer cell line HT29 by means of RNA interference. Both Id1 and Id3 were double-knockdown since they are known to functionally compensate each other, and the downregulation of either is not enough for the inhibition of their effects. Parental HT29 cells and the empty vector (mock) transfectants were used as control. Oxaliplatin, one component of FOLFOX6, which is one of the standard treatment protocols for colorectal cancer, was chosen as the chemotherapeutic agent. The chemosensitivity was investigated as follows: the proliferative activity was analyzed by the MTS assay, the induction of apoptosis, by the flow-cytometry after double-staining of the cells with AnnexinV/PI. Induction of autophagy was investigated by flow-cytometry after staining of the cells with acridine orange for the detection of AVOs. The changes of the cell cycle were investigated by flow-cytometry after staining of the cells with propidium iodide (PI).

Results: Id double-knockdown resulted in increased chemosensitivity to oxaliplatin, as observed by the reduced proliferative ability compared with parental and mock cells. And the reduced proliferative activity was associated with the arrest of cell to the G2-M phase of the cell cycle, and the increased cell apoptosis. The chemosensitivity of Id double-knockdown cells seemed to be associated with decreased ability to induce autophagy in response to the chemotherapeutic agent.

Conclusions: Id1, 3 double-knockdown resulted in increased chemosensitivity of colorectal cancer cells to oxaliplatin, dependent on the cell cycle arrest and apoptosis induction. And the decreased ability to induce autophagy seemed to be a mechanism responsible for this effect. From these results, we concluded that Id proteins play an important role in the chemoresistance of colorectal cancer, and downregulation of Id should be a promising strategy to improve chemosensitivity of Id expressing cancers.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3908.

Abstract 3367: CD133- colorectal cancer cells have higher chemo-resistance ability than CD133+cells

(Background and purpose)

Recently, many reports suggest that a limited population of tumor cells have the capability of tumorigenesis. These cells, called cancer stem cells (CSCs) or tumor initiating cells, are suggested to be involved in tumor recurrence after long interval as well as in chemo-resistance. There are several CSC markers, including CD44 and CD133. CD133, originally a hematopoietic stem cell marker, was identified also as a stem cell marker for various tumor types. In the present study, we aimed to compare the characteristics of CD133+ and CD133- colorectal cancer cells to test the hypothesis of CD133 being a potential specific marker for colorectal CSCs.

(Methods)

Using auto magnetic activated cell sorting (MACS), the human colon cancer cell line LoVo was separated into CD133+ and CD133- cell subpopulations, and their sensitivity to 5-FU, specially focusing on apoptosis and autophagy inductions were investigated. The sensitivity of CD133+ and - cells to 5-FU was tested by the MTS assay. And the induction of apoptosis was analyzed by flow-cytometry, after double-staining with annexin V-FITC/PI. The expression of β1-integrins was analyzed by flow-cytometry, and their ability to bind extracellular matrix (ECM) proteins was evaluated by the adhesion assay. Induction of autophagy was investigated by flow-cytometry after staining with acridine orange, and by Western blot for the expressions of the LC3 protein.

(Results)

After MACS isolation, CD133+ and CD133- cells were separately cultured. The purity of the obtained cell populations was more than 98%. After several days of culture, the proportion of CD133+ and CD133- cells was not changed in both cell populations during about a month. CD133- cells showed higher resistance to 5-FU than CD133+cells, in vitro. It was dependent on the higher induction of apoptosis in CD133+ cells. CD133+ cells had lower expression of β1-integrins compared with CD133- cells, and consequently, their ability to adhere ECM proteins was weaker. Additionally, AVOS formation was weaker in CD133+ cells, as well as the expression of LC3-II.

(Discussion)

CD133+ cells were more sensitive to 5-FU than CD133- cells, and it may be dependent on the higher ability of CD133- cells to induce autophagy in response to 5-FU. Additionally, CD133- cells had higher ability to adhere to ECM proteins through β1-integrins, and it may be another mechanism of chemo-resistance. Taking these results, higher ability to adhere to ECM proteins may confer resistance to 5-FU by improving the ability of cells to induce autophagy as a cell survival mechanism. Presently, there is controversy regarding CD133 as a specific marker of CSCs, but from our results, CD133- cells are more resistant to chemotherapy, one typical feature of CSCs. Therefore, we concluded that CD133 may not be used as a single CSC marker, but on the other hand, it may be a potential marker for the prediction of chemo-sensitivity in colorectal cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3367.

Abstract 4841: Inhibition of autophagy potentiates the anti-angiogenic effects of sulforaphane

Background: Sulforaphane (SUL), a kind of isothiocyanate, has been reported to exert strong inhibitory effects on various cancer cells by inducing apoptosis and/or cell cycle arrest. Recently autophagy induction by cancer cells has been focused as a defense mechanism against various proapoptotic agents, which may result in resistance to cancer therapy. Therefore, inhibition of autophagy in cancer cells may be a novel strategy in cancer therapy.

Tumor cells depend on angiogenesis for their growth and metastasis and, therefore, anti-angiogenic therapy is a promising anti-cancer strategy.

In the present study, we aimed to investigate the anti-angiogenic effect of SUL, and the possible induction of autophagy by tumor vascular endothelial cells as a defense mechanism against SUL-induced apoptosis. Additionally, we investigated the role of specific autophagy inhibitor in potentiating the proapoptotic effect of SUL. For these purposes, the human umbilical vein endothelial cells (HUVECs) were used as the in vitro model of tumor endothelium.

Methods: HUVECs were isolated from umbilical cords, obtained from normal pregnants at the delivery, from whom informed consent was obtained. Cells were treated with SUL at different concentrations, and their proliferative activity was assessed by the MTS assay. Apoptosis was investigated by flow-cytometry after double-staining with FITC-conjugated Annexin-V and propidium iodine. The formation of acidic vesicular organelles (AVOs) was detected by fluorescence microscopy and flow-cytometry following staining with acridine orange. Detection of light chain 3 (LC3) levels was investigated by Western blot. Localizations of LC3 and cytochrome c were analyzed by immunocytochemistry. Finally, the vascular-like structure formation on Matrigel was investigated. The role of the specific autophagy inhibitor (3-methyladenine (3-MA)) in potentiating the effects of SUL was similarly investigated.

Results: The proapoptotic effect was observed by treatment of cells with relatively high concentrations of SUL for long periods of time. At 16 hour-treatment with lower concentrations of SUL, the features of autophagy, were observed in HUVECs. Treatment of cells with 3-MA potentiated the proapoptotic effect of SUL, which was dependent on the activation of caspases and the release of cytochrome c to the cytosol. SUL dose-dependently inhibited the tube-like formation by HUVECs on Matrigel, an important event in the process of angiogenesis, and treatment of 3-MA potentiated this effect.

Conclusion: The present results demonstrate the induction of autophagy in endothelial cells as a protective reaction against the proapoptotic effect of SUL, and consequently, the potentiation of the proapoptotic effect by the inhibition of autophagy. These findings open premises for the use of autophagy inhibitors in combination with chemotherapeutic agents for the anti-angiogenic agents.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4841.

Abstract 422: (-)-Epigallocatechin-3-gallate inhibits the metastatic potential of colon cancer

Objective: Green tea catechins have been shown to be potential chemopreventive agents against various types of cancer Among them, Epigallocatechin-3-gallate (EGCG), which accounts for almost 50% of the total catechin content in green tea extract, has been focused due to its potent antioxidant effects. EGCG inhibits enzyme activities and signal transduction pathways, resulting in the suppression of cell proliferation and enhancement of apoptosis. Also, it is reported to inhibit cell invasion, angiogenesis and metastasis. However, the exact mechanisms of the anti-proliferative/anti-metastatic activities of EGCG are not completely understood. In the present study, we aimed to investigate the mechanisms of the inhibitory effect of EGCG on colon cancer cells, especially focusing on cell adhesion.

Methods: HT-29 human colon cancer cells were used. The effect of EGCG on the proliferative activity was investigated by the MTS assay. The expression of integrins was analyzed by flow-cytometry. Apoptosis induction was analyzed by flow-cytometry after double-staining of cells with AnnexinV/PI. The ability of cells to adhere to extracellular matrix (ECM) proteins was tested by the adhesion assay on fibronectin, collagen and laminin.

Results: EGCG dose-dependently decreased the ability of HT-29 cells to proliferate on and adhere to ECM proteins. The amount of cell surface integrins, however, was not affected by EGCG. Additionally, EGCG treatment did not induce apoptosis of HT-29 cells. Therefore, the affection of the proliferative activity by EGCG was attributed to anoikis.

Conclusions: EGCG dose-dependently decreased the ability of colon cancer cells to proliferate on and to adhere to ECM proteins. It was not dependent on changes in the expression of β1-integrins, but on the affection of the ability of β1-integrins to bind the ECM proteins. Binding to the ECM proteins is an important event for cancer cells to proliferate, migrate, invade, and form metastatic lesions. Therefore, EGCG, by affecting the ability of colon cancer cells to adhere to ECM proteins, may be a potential agent for the prevention and/or treatment of colon cancer metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 422.

Abstract 1749: The downregulated expression of adiponectin receptors (AdipoR1, R2) in human colorectal cancer

[Background] Adiponectin is 30 kDa adipocytokine hormone secreted by the adipose tissues, which mediates antineoplastic as well as anti-angiogenic effects after binding to its receptors, Adipo-R1 and Adipo-R2, which has been reported to be expressed in colorectal cancer tissue and cell lines. Recent studies have shown decreased levels of adiponectin in sera of patients with various types of cancer, including colorectal. And a recent study demonstrated that adiponectin expression is significantly associated with high histological grade tumors and low microvessel density count in colorectal cancer, suggestive of an anti-angiogenic role for adiponectin in colorectal cancer. However, presently, the expression and function of adiponectin receptors in tumor tissue have not been well characterized. Thus, in the present study, we aimed to study the expression of adiponectin receptors in colorectal cancer tissues, and investigate on their clinicopathological implications.

[Methods] Surgically resected specimens from 48 patients with colorectal cancer, receiving surgical operation in our surgical department in the period between November 2008 and July 2009, were analyzed. The study was approved by the Human Ethics Committee of the University of Tokyo. The messages and protein expressions of AdipoR1 and AdipoR2 were evaluated by real-time RT-PCR and immunohistochemistry, respectively, in cancer tissues and the matched normal counterparts.

[Results] The mean age of the patients was 66.79±11.85 years. The levels of expression of both AdipoR1/AdipoR2, normalized with the internal control (beta-actin), were significantly lower in cancer specimens compared with normal mucosa (0.966±0.392, vs1.366±0.408, p&lt;0.001 and 0.918±0.309, vs1.596±0.459, p&lt;0.001, respectively for AdipoR1 and Adipo R2). The mRNA levels of AdipoR1 and AdipoR2 showed a tendency of decrease in tumors with nodal metastases and the difference was significant with AdipoR2 (p&lt;0.05). Immunohistochemistry with polyclonal Abs showed a consistent reduction in protein expression of both receptors in cancer tissues in comparison with the normal counterparts.

[Conclusion] Both receptors were downregulated in colorectal cancer, as confirmed by the mRNA and the protein expressions, and AdipoR2 seemed to be associated with nodal metastases. This downregulation seems to be associated with poorer prognosis of colorectal cancer, and may be an escape mechanism of cancer cells from the suppressive effects of adiponectin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1749.

Abstract 85: Chloroquine potentiates the 5-fluorouracil-induced cell cycle arrest on HT-29 colon cancer cells

Introduction

Autophagy is a self-degradation process that is essential for cell survival, development, and homeostasis. During autophagy, cytoplasmic organelles and proteins damaged by the cellular stress, such as starvation, hypoxia and chemotherapy, are recycled and converted into more essential proteins. Thus, induction of autophagy in cancer cells may result in cell adaptation against anticancer agents, consequently leading to resistance to therapy. Chloroquine (CQ), a worldwide used anti-malarial drug, is a lysosomotropic drug, also known to inhibit autophagy by impairing the autophagic protein degradation. On the other hand, 5-Fluorouracil (5-FU) is the most common chemotherapeutic agent for colorectal cancer, which inhibits DNA synthesis and induces apoptosis and/or cell cycle arrest in colon cancer cells. In the present study, we aimed to investigate the induction of autophagy as a mechanism of resistance of colon cancer cells to 5-FU-based chemotherapy, and the role of autophagy inhibition, by CQ, in potentiating the effect of 5-FU, especially focusing on cell cycle arrest.

Procedure

The human colon cancer cell line HT-29 was used. Cells were treated with CQ and/or 5-FU at various concentrations, and the changes in the proliferative activity were investigated, especially focusing on the induction of autophagy, the changes of cell cycle, and the development of apoptosis. The proliferative ability of HT-29 was analyzed by the MTS assay. The cell cycle was evaluated by flow-cytometry after staining of cells with PI, and autophagy was quantified by the analysis of the formation of acidic vesicular organelles (AVOs) by flow-cytometry after staining of cells with acridine orange (AO), and additionally, by the analysis of the expression of LC3-II by Western blot. Apoptosis was quantified by flow-cytometry after double-staining of the cells with AnnexinV/PI. Finally, to evaluate the long-term viability of the cells, the colony formation assay was performed.

Results

Treatment of HT-29 with 5-FU resulted in significant inhibition of the proliferative activity, compared with untreated cells. Treatment of the cells with CQ prior to exposure to 5-FU, potentiated the inhibitory effect. And it was dependent on the increase of the percentage of cells in G0/G1-phase, and the simultaneous decrease of cells in G2/M-phase. Also a partial increase of apoptotic cells was observed. These effects were dependent on the decreased expression of cyclin-dependent kinase-2 and the increased expression of p21Cip1, p27Kip1, important regulators of the cell cycle progression from G1 to S phase. Therefore, pre-treatment of HT-29 with the autophagy inhibitor, CQ, resulted in potentiation of the G0/G1 phase cell cycle arrest induced by 5-FU.

Conclusion: The combination therapy using inhibitor of autophagy, such as CQ, should be a novel therapeutic modality to improve efficacy of 5-FU-based chemotherapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 85.

Inhibition of autophagy potentiates sulforaphane-induced apoptosis in human colon cancer cells

BACKGROUND

Sulforaphane (SUL), an isothiocyanate naturally present in widely consumed vegetables, particularly broccoli, has recently attracted attention due to its inhibitory effects on tumor cell growth by inducing apoptosis. We investigated the ability of SUL to induce autophagy in human colon cancer cells and whether inhibition of autophagy could potentiate the proapoptotic effect of SUL.

METHODS

The proliferation of cells treated with SUL was assessed by MTS assay and colony-forming assay. Apoptosis and caspases activity were investigated by flow cytometry. The formation of acidic vesicular organelles (AVOs) was detected in acridine-orange-stained cells by flow cytometry. Western blotting was used for the detection of light chain 3 (LC3). Localizations of LC3 and cytochrome c were analyzed by immunocytochemistry.

RESULTS

The proapoptotic effect was observed by treatment of cells with relatively high concentrations of SUL for long periods of time. After 16 h of treatment, evident formation of AVOs and recruitment of LC3 to autophagosomes, features of autophagy, were observed. Treatment of cells with a specific autophagy inhibitor (3-methyladenine) potentiated the proapoptotic effect of SUL, which was dependent on the activation of caspases and the release of cytochrome c to the cytosol.

CONCLUSION

The present results demonstrate induction of autophagy in colon cancer cells as a protective reaction against the proapoptotic effect of SUL, and consequently, the potentiation of the proapoptotic effect by autophagy inhibition. These findings provide a premise for use of autophagy inhibitors in combination with chemotherapeutic agents for treatment of colorectal cancer.

Id1/Id3 knockdown inhibits metastatic potential of pancreatic cancer

BACKGROUND

The Id (inhibitor of DNA binding/differentiation) proteins belong to the helix-loop-helix transcriptional regulatory factors, and play important roles in tumor development. Previously, we and others have shown that targeting Id in tumor cells could have important clinical implications. In the present study, we aimed to evaluate the effects of Id inhibition in human pancreatic cancer cells.

MATERIALS AND METHODS

Id1 and Id3 were stably double-knockdown in human pancreatic cancer cell line MIA-Paca2 by means of RNA interference. Expression of Id and integrins were analyzed by flow-cytometry. Cell proliferation was evaluated by MTS assay. Migration was measured by wound closure assay. Adhesion assay was performed to evaluate binding capacity for different extracellular matrix proteins. Finally, in vivo properties of tumor cells were observed in a mouse model of peritoneal metastasis.

RESULTS

Id1/Id3 double-knockdown resulted in decreased ability of pancreatic cancer cells to proliferate and migrate. In addition, Id1/Id3 double-knockdown caused decreased expression of integrins alpha3, alpha6, and beta1, and consequently reduced adhesion of tumor cells to laminin. Finally, peritoneal metastases of Id1/Id3 double-knockdown tumor cells were significantly reduced.

CONCLUSIONS

We concluded that the Id proteins play a pivotal role in the development of peritoneal metastasis of pancreatic cancer, and consequently, their targeting would be a novel strategy for the prevention and treatment of pancreatic cancer.

Plaunotol and geranylgeraniol induce caspase-mediated apoptosis in colon cancer

BACKGROUND

Plaunotol, a kind of isoprenoid extracted from a Thai medical plant, plau-noi, is structurally similar to geranylgeraniol (GGOH), another isoprenoid reported to exert strong anticancer effects. Recently, we have reported on its inhibitory effects on tumor angiogenesis and direct effects on gastric cancer cells. Here, we aimed to test whether plaunotol could have some therapeutic effect on colon cancer.

MATERIALS AND METHODS

Human colon cancer cell line DLD1 was used. Tumor cells were cultured in the presence of plaunotol or GGOH, and their proliferation was measured by MTS assay. Apoptosis was evaluated by Annexin V and propidium iodide double-staining or terminal-deoxynucleotidyl assay. The activation of caspase-3, -8, and -9 was analyzed by flow cytometry and Western blot analysis for PRRP cleavage.

RESULTS

Plaunotol and GGOH strongly inhibited the proliferative activity of DLD1, dependent on induction of apoptosis. The induction of apoptosis by either plaunotol or GGOH was dependent on the activation of both caspase-8 and caspase-9 pathways.

CONCLUSIONS

Plaunotol would be a potential anticancer agent against colon cancer, and since it is already available in Japan and Thailand for clinical use as an anti-ulcer/antigastritis agent, clinical trials will be designed to confirm the present findings.