Surgical adjuvant therapy for colorectal cancer: current approaches and future directions

Targeting PLA2G16, a lipid metabolism gene, by Ginsenoside Compound K to suppress the malignant progression of colorectal cancer

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PLA2G16 is up-regulated in CRC, and high expression of PLA2G16 is associated with the advanced stages.

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PLA2G16 promotes the malignant progression of CRC through the Hippo signaling pathway.

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GCK exerts its anti-CRC effects by inhibiting the protein expression of PLA2G16.

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Provide a new insights towards the development of effective therapeutic strategies for CRC treatment by targeting PLA2G16.

Introduction

Objectives

Methods

Results

Conclusion

Targeted delivery of 20(S)-ginsenoside Rg3-based polypeptide nanoparticles to treat colon cancer

Colorectal cancer (CRC) is a major malignancy characterized by a high metastasis rate. Systematic chemotherapy is important for patients with advanced CRC. However, many limitations (e.g., side effects to normal organs, shorter circulation time, and unsatisfactory tumor inhibition results) of traditional chemotherapy restrict its further application. Thus, it is necessary to find a method to overcome these challenges and improve the efficacy of CRC treatment. In this study, 20(S)-ginsenoside (Rg3) co-loaded poly(ethylene glycol)-block-poly(L-glutamic acid-co-L-phenylalanine) (mPEG-b-P(Glu-co-Phe)) nanoparticles (Rg3-NPs) were prepared. mPEG-b-P(Glu-co-Phe)-based drug delivery systems are pH sensitive that can target cancer cells and circulate for longer in blood. Rg3 could be released rapidly from the nanoparticles within tumor cells. A subcutaneous colon cancer mouse model was developed to evaluate the anticancer efficiency of the Rg3-NPs. The in vivo study indicated that the Rg3-NPs could significantly inhibit tumor proliferation by decreasing the expressions of proliferating cell nuclear antigen, resulting in tumor apoptosis through the increased expressions of caspase-3. Our study demonstrated the marked potential of the Rg3-NPs to treat CRC.

Systematic identification of Celastrol-binding proteins reveals that Shoc2 is inhibited by Celastrol

Colorectal cancer (CRC) is the third most commonly diagnosed cancer. Celastrol exhibits anti-tumor activities in a variety of cancers. However, the effect of Celastrol on human CRC and the underlying mechanisms still need to be elucidated. The present study aimed to use in vitro and in vivo methods to clarify the anti-tumor effect of Celastrol and use protein microarrays to explore its mechanisms. We demonstrated that Celastrol effectively inhibited SW480 CRC cell proliferation. Two weeks of Celastrol gavage significantly inhibited the growth of xenografts in nude mice. A total of 69 candidate proteins were identified in the protein microarray experiment, including the most highly enriched protein Shoc2, which is a scaffold protein that modulates cell motility and metastasis through the ERK pathway. Celastrol significantly inhibited ERK1/2 phosphorylation in cell lines and xenograft tumors. Down-regulation of Shoc2 expression using Shoc2 siRNA also inhibited ERK1/2 phosphorylation. Furthermore, down-regulation of Shoc2 expression also significantly inhibited proliferation, colony formation, and migration functions of tumor cells. In addition, the LD0 of Celastrol by gavage is equal or more than 80 mg/kg in C57 male mice. In summary, we unraveled the anti-CRC function of Celastrol and confirmed for the first time that it inhibited the ERK1/2 pathway through binding to Shoc2.

Spindle Assembly Checkpoint as a Potential Target in Colorectal Cancer: Current Status and Future Perspectives

Colorectal cancer (CRC), one of the most common malignancies worldwide, is often diagnosed at an advanced stage, and resistance to chemotherapeutic and existing targeted therapy is a major obstacle to its successful treatment. New targets that offer alternative clinical options are therefore urgently needed. Recently, perturbation of the spindle assembly checkpoint (SAC), the surveillance mechanism that maintains anaphase inhibition until all chromosomes reach the metaphase plate, has been regarded as a promising target to fight cancer cells, either alone or in combination regimens. Consistent with this strategy, many cancers, including CRC, exhibit altered expression of SAC genes. In this article, we review our current knowledge on SAC activity status in CRC, and on current anti-CRC strategies and future therapeutic perspectives on the basis of SAC targeting experiments in vitro and in animal models.

Complete mesocolic excision and extended (D3) lymphadenectomy for colonic cancer: is it worth that extra effort? A review of the literature

PURPOSE

Recent interest in complete mesocolic excision (CME) with central vascular ligation (CVL) or extended (D3) lymphadenectomy (EL) for curative resection of colon cancer has been driven by published series from experienced practitioners showing excellent survival outcomes and low recurrence rates. In this article, we attempt to clarify the role of CME or EL in modern colorectal surgery.

METHODS

A narrative review of the evidence for CME and EL in the curative treatment of colon cancer.

RESULTS

The principal of CME surgery, similar to total mesorectal excision (TME) for rectal cancer, is the removal of all lymphatic, vascular, and neural tissue in the drainage area of the tumour in a complete mesocolic envelope with intact mesentery, peritoneum and encasing fascia. Extended (D3) lymphadenectomy (EL) is based on similar principles. Sound anatomical and oncological arguments are made to support the principles of removing the tumor contained within an intact mesocolic facial envelope together with an extended lymph node harvest. Excellent oncological outcomes with minimal morbidity and mortality have been reported. This has led to calls for the standardisation of surgery for colon cancer using CME. However, there is conflicting evidence regarding the prognostic benefit of greater lymph node harvests and the evidence for an oncological benefit of CME is limited by methodology flaws and several potential confounding factors.

CONCLUSIONS

Although there is a reasonable anatomical and oncological basis for these techniques, there are no randomised controlled trials from which to draw confident conclusions and there is insufficient consistent high quality evidence to recommend widespread adoption of CME.

Necessary circumferential resection margins to prevent rectal cancer relapse after abdomino-peranal (intersphincteric) resection

PURPOSE

The purpose of this study was to determine the adequate circumferential resection margin (CRM) for abdomino-peranal (intersphincteric) resection (ISR) that would prevent the relapse of rectal cancers.

METHODS

The records of 41 cases that underwent curative ISR for rectal cancer were retrospectively reviewed. The relapse-free survival rates and overall survival rates were evaluated and correlated with the maximum depth of the inner muscularis layer reached during ISR (i.e., the radial margin [RM] and distal margin [DM]). Cases were divided into three groups based on the sizes of the RM and DM: (1) group A (RM >2 mm and DM >1.5 cm), (2) group B (RM >2 mm or DM >1.5 cm but not both), and (3) group C (RM <2 mm and DM <1.5 cm).

RESULTS

The relapse-free survival rates of the cases in group C were lower than those in the cases of group A or group B (p = 0.002 and 0.037, respectively). The resection margins required to prevent rectal cancer relapse were >2 mm for the RM and >1.5 cm for the DM. For these margins, the intersphincteric space had to be entered (i.e., between the internal and external anal sphincters).

CONCLUSION

It is critical to enter the intersphincteric space to ensure an adequate CRM (RM >2 mm and DM >1.5 cm) for preventing rectal cancer recurrence after ISR.

Sex differences between cT4b and pT4b rectal cancers

We retrospectively evaluated rectal cancer surgery cases in which resection had been performed for invasion of other organs in terms of pathologic findings from the viewpoint of sex differences. We enrolled 61 consecutive patients with rectal cancer who had undergone curative surgery with resection of invaded adjacent organs. We investigated invasion of adjacent organs in terms of pathologic findings according to sex differences. Among males, 4 cases (13.8%) had received combined radical resections of more than 2 organs, while the number of such female cases was 15 (46.9%). The difference between males and females was statistically significant (P = 0.006). Among male cases, histopathologic invasion was present in 4 (13.8%), while 9 female cases (28.1%) showed this feature. Nevertheless, there was not a statistically significant difference between males and females (P = 0.08); the rate in females was roughly twice that in males. No significant difference was recognized in the overall survival rates between males and females, but more females than males experienced local recurrence. In cases with rectal cancer invading neighboring organs, the effect of the invasion must be carefully determined, and the most appropriate operative approach selected accordingly.

Clinical significance of aberrant mammalian target of rapamycin expression in stage IIIB colon cancer

The aim of the present study was to investigate the significance of aberrant expression of mammalian target of rapamycin (mTOR) and the activated form of mTOR kinase, phosphorylated mTOR (pmTOR), in human stage IIIB colon cancer. The expression of mTOR and pmTOR was detected by immunohistochemistry in the tumor tissue of stage IIIB colon cancer patients. The association between the expression of mTOR, pmTOR and clinicopathological parameters of patients was analyzed. The positive expression of mTOR and pmTOR was observed to be higher in 75.5% (80/106) and 76.4% (81/106) of the 106 colon cancer specimens, compared with the adjacent normal tissues. The high level of pmTOR expression was found to be significantly higher in the invasive tumor front cells and resulted in a higher risk of mortality. The results suggested that mTOR and pmTOR may be promising clinical markers and present novel molecular targets for designing novel therapeutic strategies to treat this malignancy.

Prevention of carcinogenesis and development of gastric and colon cancers by 2-aminophenoxazine-3-one (Phx-3): direct and indirect anti-cancer activity of Phx-3

2-Aminophenoxazine-3-one (Phx-3), an oxidative phenoxazine, exerts strong anticancer effects on various cancer cell lines originating from different organs, in vitro. This article reviews new aspects for the prevention of carcinogenesis and development of gastric and colon cancers by Phx-3, based on the strong anticancer effects of Phx-3 on gastric and colon cancer cell lines (direct anticancer effects of Phx-3 for preventing development of cancer), the bacteriocidal effects of Phx-3 against Helicobacter pylori associated with carcinogenesis of gastric cancer (indirect anticancer effects for preventing carcinogenesis of gastric cancer), and the proapoptotic activity of Phx-3 against human neutrophils involved in the incidence of ulcerative colitis associated with a high colon cancer risk (indirect anticancer effects for preventing carcinogenesis of colon cancer).

Detailed stratification of TNM stage III rectal cancer based on the presence/absence of extracapsular invasion of the metastatic lymph nodes

BACKGROUND

The presence/absence of extracapsular invasion in metastatic lymph nodes has been reported as being significantly correlated with the prognosis in a wide variety of cancers. However, the influence of extracapsular invasion in the metastatic lymph nodes on the prognosis in patients with stage III rectal cancer has not yet been investigated.

OBJECTIVE

We investigated the presence/absence of extracapsular invasion in the metastatic nodes of the relevant main/lateral lymph node group in patients with rectal cancer to determine the usefulness of this parameter for stratifying the prognosis of patients with stage III rectal cancer.

DESIGN

This was a single-institution study.

SETTINGS

This study was conducted at a single institution.

PATIENTS

We enrolled 101 consecutive patients with stage III rectal cancer who had undergone curative surgery with extended lymph node dissection and investigated the presence/absence of extracapsular invasion in the regional metastatic lymph nodes to determine the usefulness of such stratification for a more precise prediction of the patient prognosis.

MAIN OUTCOME MEASURES

The main outcomes measured were the disease-free and overall survival rates.

RESULTS

Univariate analysis revealed a significantly poorer prognosis, in terms of both the disease-free survival rate (p = 0.003) and overall survival rate (p = 0.008), of the pN3-extracapsular invasion-positive cases in comparison with the pN3-extracapsular invasion-negative cases. Multivariate analysis revealed the presence/absence of extracapsular invasion in the metastatic lymph nodes as the only variable that was statistically significantly associated with the disease-free survival rate (p = 0.011).

LIMITATIONS

This was a retrospective study in a small number of patients from a single institution. There were no comparator groups.

CONCLUSIONS

Detailed stratification of pN3 cases based on the presence/absence of extracapsular invasion in metastatic lymph nodes has the potential to contribute significantly to more available prediction of the prognosis of patients with stage III colorectal cancer.

Frequency of HER-2 positivity in rectal cancer and prognosis

In patients with advanced rectal cancer (cUICC II and III) multimodality therapy resulted in better long-term local tumor control. Ongoing clinical trials are focusing on therapy intensification to improve disease-free (DFS) and cancer-specific survival (CSS), the integration of biomarkers for prediction of individual recurrence risk, and the identification of new targets. In this context, we investigated HER-2, a member of the epidermal growth factor receptor family, whose expression pattern and role was unclear in rectal cancer. A total of 264 patients (192 male, 72 female; median age 64 y) received standardized multidisciplinary treatment according to protocols of phase II/III trials of the German Rectal Cancer Study Group. HER-2 status was determined in pretherapeutic biopsies and resection specimens using immunohistochemistry scoring and detection of silver in situ hybridization amplification. Tumors with an immunohistochemistry score of 3 or silver in situ hybridization ratios of ≥2.0 were classified HER-2 positive; these results were correlated with clinicopathologic parameters [eg, resection (R) status, nodal status ((y)pN)], DFS, and CSS. Positive HER-2 status was found in 12.4% of biopsies and in 26.7% of resected specimens. With a median follow-up of 46.5 months, patients with HER-2 positivity showed in trend a better DFS (P=0.1) and a benefit in CSS (P=0.03). The 5-year survival rate was 96.0% (HER-2 positive) versus 80.0% (HER-2 negative). In univariate and multivariate analyses, HER-2 was an independent predictor for CSS (0.02) along with the (y)pN status (P<0.00001) and R status (P=0.011). HER-2 amplification is detectable in a relevant proportion (26.7%) of rectal cancer patients. For the development of innovative new therapies, HER-2 may represent a promising target and should be further assessed within prospective clinical trials.

Kanglaite injection combined with FOLFOX4 regimen for the treatment of advanced colorectal cancer: An analysis of 20 cases

AIM: To evaluate the efficacy and toxicity of Kanglaite injection combined with FOLFOX4 regimen in the treatment of advanced colorectal cancer.

METHODS: In total, 40 patients with advanced colorectal cancer were randomly divided into treatment group and control group. The control group was treated using the FOLFOX4 regimen, and the treatment group were treated using the FOLFOX4 regimen combined with intravenous infusion of Kanglaite injection. After two cycles of therapy, the efficacy and toxicity were evaluated.

RESULTS: The objective response rate and disease control rate were higher in the treatment group than in the control group, but the differences were not significant (25.0% vs 20.0%, P > 0.05; 85.0% vs 75.0%, P > 0.05). The stable rate of TCM syndromes after chemotherapy was 85.0% for the treatment group and 50.0% for the control group (P < 0.05). KPS score and body weight increased significantly in the treatment group after therapy (both P < 0.05). QOL score did not differ significantly between the two groups. After therapy, the numbers of T lymphocytes (CD3+), T-assisted, induced lymphocytes (CD3+CD4+) and NK cells (CD16+CD56+) increased in the treatment group, but decreased in the control group (all P < 0.05). Leucopenia incidence in the treatment group was lower than that in the control group (P < 0.05). The incidences of other adverse reactions showed no significant differences between the two groups.

CONCLUSION: Kanglaite injection combined with FOLFOX4 regimen can improve physical condition, enhance immune function, and reduce chemotherapy toxicity in the treatment of advanced colorectal cancer.

Visinin-like protein-1 overexpression is an indicator of lymph node metastasis and poor prognosis in colorectal cancer patients

Lymph node metastasis is an important factor determining outcome from colorectal cancer (CRC). Identification of molecular markers useful to predict lymph node metastasis is urgently needed. Our objective was to identify genes useful for characterization and prediction of lymph node metastasis in CRC. Gene expression profiles of cancer were determined by human U133 Plus 2.0 GeneChip® in 24 CRC patients, and patients with and without lymph node metastasis were compared. We focused on the visinin-like protein-1 (VSNL-1) gene and evaluated VSNL-1 mRNA expression levels with reverse transcriptase-polymerase chain reaction and immunohistochemical methods. Immunohistochemical evaluation of VSNL-1 mRNA expression was also performed in 143 other CRC patients to determine clinicopathological significance of VSNL-1. Twenty-four novel discriminating genes showed expression significantly different between patients with and without lymph node metastasis. Mean level of VSNL-1 mRNA expression in tumor tissue with lymph node metastasis was significantly higher than that in tissue without lymph node metastasis. Immunohistochemical examination demonstrated immunoreactivity for VSNL-1 in cytoplasm of the cancer cells with lymph node metastasis. High VSNL-1 expression was significantly associated with lymphatic invasion in stage II disease (p = 0.0061) and number of lymph node metastases in stage III disease (p = 0.0461). Patients with high VSNL-1 expression had significantly poorer prognosis than those with low expression in stage III disease (p = 0.045). This study is the first to demonstrate a prognostic role for VSNL-1 at the mRNA level, suggesting the possible usefulness of VSNL-1 as a predictor of lymph node metastasis and poor prognosis in CRC.

Locally advanced prostate cancer: a population-based study of treatment patterns

Study Type--Therapy (practice patterns). Level of Evidence 2b. What's known on the subject? And what does the study add? The treatment of locally advanced prostate cancer varies widely even though there is level one evidence supporting the use of multimodality therapy as compared with monotherapy. This study defines treatment patterns of locally advanced prostate cancer within the United States and identifies predicators of who receives multimodality therapy rather than monotherapy.

OBJECTIVE

• To identify treatment patterns and predictors of receiving multimodality therapy in patients with locally advanced prostate cancer (LAPC).

PATIENTS AND METHODS

• The cohort comprised patients ≥66 years with clinical stage T3 or T4 non-metastatic prostate cancer diagnosed between 1998 and 2005 identified from the Surveillance, Epidemiology and End Results (SEER) cancer registry records linked with Medicare claims. • Treatments were classified as radical prostatectomy (RP), radiation therapy (RT) and androgen deprivation therapy (ADT) received within 6 and 24 months of diagnosis. • We assessed trends over time and used multivariable logistic regression to identify predictors of multimodality treatment.

RESULTS

• Within the first 6 months of diagnosis, 1060 of 3095 patients (34%) were treated with a combination of RT and ADT, 1486 (48%) received monotherapy (RT alone, ADT alone or RP alone), and 461 (15%) received no active treatment. • The proportion of patients who received RP increased, exceeding 10% in 2005. • Use of combined RT and ADT and use of ADT alone fluctuated throughout the study period. • In all 6% of patients received RT alone in 2005. • Multimodality therapy was less common in patients who were older, African American, unmarried, who lived in the south, and who had co-morbidities or stage T4 disease.

CONCLUSIONS

• Treatment of LAPC varies widely, and treatment patterns shifted during the study period. • The slightly increased use of multimodality therapy since 2003 is encouraging, but further work is needed to increase combination therapy in appropriate patients and to define the role of RP.

The Akt inhibitor ISC-4 activates prostate apoptosis response protein-4 and reduces colon tumor growth in a nude mouse model

PURPOSE

Prostate apoptosis response protein-4 (Par-4) sensitizes cells to chemotherapy; however, Akt1 inactivates Par-4. Previously we showed that Par-4-overexpressing colon cancer cells responded more readily to 5-fluorouracil (5-FU) than their wild-type counterparts. In this study we investigated (i) the effects of the Akt inhibitor, phenylbutyl isoselenocyanate (ISC-4), on tumor growth in nude mice and (ii) bystander effect of Par-4-overexpressing cells on wild-type tumor growth.

EXPERIMENTAL DESIGN

Mice (n = 80) were injected with wild-type HT29 human colon cancer cells in the right flank. Forty of the mice were also injected in the left flank with HT29 cells engineered to overexpress Par-4. The mice were treated with 5-FU, ISC-4, a combination, or vehicle.

RESULTS

ISC-4 reduced tumor growth, with or without 5-FU. When Par-4-overexpressing tumors were present, wild-type tumors grew more slowly compared to when no Par-4-overexpressing tumors were present. The level of Par-4 protein as well as the Par-4 binding protein, GRP78, was increased in wild-type cells growing in the same mouse as Par-4-overexpressing tumors compared with wild-type tumors growing without Par-4-overexpressing tumors.

CONCLUSIONS

Par-4-overexpressing tumors exhibited a bystander effect on wild-type tumors growing distally in the same mouse. This suggests that gene therapy need not achieve total penetration to have a positive effect on tumor treatment. Inhibition of Akt with ISC-4 inhibited tumor growth and had a greater effect on cells overexpressing Par-4. The data indicate ISC-4 alone or in combination with Par-4 can greatly reduce tumor growth.

Extracapsular invasion as a risk factor for disease recurrence in colorectal cancer

AIM: To evaluate the presence of extracapsular invasion (ECI) in positive nodes as a predictor of disease recurrence disease in colorectal cancer.

METHODS: Two hundred and twenty-eight consecutive patients who underwent colorectal resection were identified for inclusion in this study, of which 46 had positive lymph nodes. Among 46 cases with stage IIIcolorectal cancer, 16 had ECI at positive nodes and 8 had disease recurrence. The clinical and pathological features of these cases were reviewed.

RESULTS: In the univariate analysis, the number of positive lymph nodes and depth of tumor invasion were significantly associated with the presence of ECI at positive nodes. Multivariate analysis demonstrated that only ECI was a predictor of recurrence. The recurrence-free interval differed significantly among patients with ECI at positive nodes.

CONCLUSION: Our results suggest that ECI at metastatic nodes can identify which cases are at high risk of short-term disease recurrence in colorectal cancer.

Dual blockade of phosphatidylinositol 3'-kinase and mitogen-activated protein kinase pathways overcomes paclitaxel-resistance in colorectal cancer

Paclitaxel, one of key drugs to treat a wide range of malignancies, exhibits relative low sensitivity for colorectal cancer. The present study was to examine whether and how phosphatidylinositol 3'-kinase (PI3K) signals affect the sensitivity of colorectal cancer to paclitaxel. Four colorectal cancer cell lines were exposed to paclitaxel in the presence of PI3K signal inhibitors, such as LY294002, siRNA for Akt, or rapamycin, with or without MAPK inhibitor, PD98059. Cell viability and apoptosis were determined by MTT assay, cell cycle analysis in flow cytometer and Hoechst nuclear staining. To analyze the PI3K activity, the expression in phosphorylated Akt and downstream effectors of p70S6 kinase (S6K) were evaluated by Western blot analysis. Paclitaxel alone (5-10 nM) did not induce the apoptosis in all four cell lines. Although LY294002 alone did not affect the cell viability, it suppressed the Akt and S6K activities and induced the sub-G1 arrest/apoptosis when paclitaxel was co-administered, as well as the Akt siRNA and rapamycin did. Simultaneous blockade of PI3K and MAPK pathways more suppressed the S6K activity and further increased the apoptosis. In conclusion, PI3K is involved in low susceptibility of colorectal cancer to paclitaxel and dual PI3K/MAPK targeting agents may evolve a new paclitaxel-based chemotherapy for colorectal cancer.

Thymidylate synthase as a prognostic biomarker for locally advanced rectal cancer after multimodal treatment

Purpose

For years, 5-fluorouracil (5-FU) has been the backbone of radiochemotherapy (RCT) of locally advanced rectal cancer. Its main target, thymidylate synthase (TS), is speculated to be an important biomarker for response prediction and long-term prognosis. In this study, we analyzed TS expression in the rectal cancer tissue of 208 patients to evaluate its predictive/prognostic potential.

Methods

All patients included were diagnosed with locally advanced adenocarcinoma of the rectum (UICC II and III) and were treated within randomized clinical trials of the German Rectal Cancer Study Group. Preoperative RCT (50.4 Gy and concomitant either 5-FU or 5-FU and oxaliplatin) was administered in 167 patients followed by surgical resection with total mesorectal excision (TME). Another 41 patients received postoperative RCT. TS levels and further clinicopathological parameters were assessed in univariate and multivariate analyses. Additionally, a TS gene polymorphism was analyzed with respect to the intratumoral protein levels.

Results

Low TS expression in pretreatment biopsies correlated with impaired patient survival (p = 0.015). Analysis of a 28-bp repeat revealed a correlation between the *3/*3 genotype and high TS expression in pretherapeutic biopsies. In this study, a correlation of TS expression and grade of RCT-induced tumor regression was not found. Histopathological examination confirmed a complete tumor remission in 16 patients (9.6%).

Analyses of the resection specimen indicated an unfavorable prognosis for patients with low intratumoral TS expression in case of detected lymph node metastases (p = 0.04).

Conclusions

TS can serve as a prognostic biomarker indicating an unfavorable prognosis for patients with low TS expression.

Electronic supplementary material

The online version of this article (doi:10.1245/s10434-011-1608-4) contains supplementary material, which is available to authorized users.

Prostate apoptosis response protein 4 sensitizes human colon cancer cells to chemotherapeutic 5-FU through mediation of an NF kappaB and microRNA network

Background

Diminished expression or activity of prostate apoptosis response protein 4 (Par-4) has been demonstrated in a number of cancers, although reports on Par-4 expression during colon cancer progression are lacking. An understanding of the molecular events in conjunction with the genetic networks affected by Par-4 is warranted.

Results

Colon cancer specimens derived from patients have significantly diminished expression of Par-4 mRNA relative to paired normal colon. Hence, the functional consequences of reintroducing Par-4 into HT29 colon cancer cells were assessed. Overexpression augmented the interaction of Par-4 with NFκB in the cytosol but not nucleus, and facilitated apoptosis in the presence of 5-fluorouracil (5-FU). Analogous findings were obtained when AKT1 pro-survival signaling was inhibited. Transcriptome profiling identified ~700 genes differentially regulated by Par-4 overexpression in HT29 cells. Nearly all Par-4-regulated genes were shown by promoter analysis to contain cis-binding sequences for NFκB, and meta-analysis of patient expression data revealed that one-third of these genes exist as a recurrent co-regulated network in colon cancer specimens. Sets of genes involved in programmed cell death, cell cycle regulation and interestingly the microRNA pathway were found overrepresented in the network. Noteworthy, Par-4 overexpression decreased NFκB occupancy at the promoter of one particular network gene DROSHA, encoding a microRNA processing enzyme. The resulting down-regulation of DROSHA was associated with expression changes in a cohort of microRNAs. Many of these microRNAs are predicted to target mRNAs encoding proteins with apoptosis-related functions. Western and functional analyses were employed to validate several predictions. For instance, miR-34a up-regulation corresponded with a down-regulation of BCL2 protein. Treating Par-4-overexpressing HT29 cells with a miR-34a antagomir functionally reversed both BCL2 down-regulation and apoptosis by 5-FU. Conversely, bypassing Par-4 overexpression by direct knockdown of DROSHA expression in native HT29 cells increased miR-34a expression and 5-FU sensitivity.

Conclusion

Our findings suggest that the initiation of apoptotic sensitivity in colon cancer cells can be mediated by Par-4 binding to NFκB in the cytoplasm with consequential changes in the expression of microRNA pathway components.

Clinical value of 18F-FDG PET/CT in assessing suspicious relapse after rectal cancer resection

AIM: To evaluate the value of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) in the restaging of resected rectal cancer.

METHODS: From January 2007 to Sep 2008, 21 patients who had undergone curative surgery resection for rectal carcinoma with suspicious relapse in conventional imaging or clinical findings were retrospectively enrolled in our study. The patients underwent 28 PET/CT scans (two patients had two scans, one patient had three and one had four scans). Locoregional recurrences and/or distant metastases were confirmed by histological analysis or clinical and imaging follow-up.

RESULTS: Final diagnosis was confirmed by histopathological diagnosis in 12 patients (57.1%) and by clinical and imaging follow-up in nine patients (42.9%). Eight patients had extrapelvic metastases with no evidence of pelvic recurrence. Seven patients had both pelvic recurrence and extrapelvic metastases, and two patients had pelvic recurrence only. ¹⁸F-FDG PET/CT was negative in two patients and positive in 19 patients. ¹⁸F-FDG PET/CT was true positive in 17 patients and false positive in two. The accuracy of ¹⁸F-FDG PET/CT was 90.5%, negative predictive value was 100%, and positive predictive value was 89.5%. Five patients with perirectal recurrence underwent ¹⁸F-FDG PET/CT image guided tissue core biopsy. ¹⁸F-FDG PET/CT also guided surgical resection of pulmonary metastases in three patients and monitored the response to salvage chemotherapy and/or radiotherapy in four patients.

CONCLUSION: ¹⁸F-FDG PET/CT is useful for evaluating suspicious locoregional recurrence and distant metastases in the restaging of rectal cancer after curative resection.

Matrix metalloproteinase-2 expression in stromal tissues is a consistent prognostic factor in stage II colon cancer

For patients with stage II colon cancer, the usefulness of adjuvant chemotherapy remains controversial. Therefore, it is important to identify high-risk indicators. The biological prognostic factors for recurrence might allow further insight into the optimal treatment strategy for patients with node-negative disease. Matrix metalloproteinase-2 seems to be one of the essential factors for tumor invasion and lymph node metastasis. In this study, we analyzed the expression of cyclooxygenase-2 and matrix metalloproteinase-2 by immunohistochemical staining in 109 patients with stage II colon cancer. A positive correlation was observed between tumor cyclooxygenase-2 and tumor matrix metalloproteinase-2 expression (P = 0.0006) and between tumor cyclooxygenase-2 and stromal matrix metalloproteinase-2 expression (P < 0.0001). Stromal matrix metalloproteinase-2 expression was associated with disease-free survival (P = 0.0095) and was shown to be an independent risk factor for recurrence by multivariate analysis. In addition, we carried out an invasion assay in vitro to investigate whether cyclooxygenase-2 and matrix metalloproteinase-2 affected the tumor-invasive potential of colon cancer cell lines. The invasion assay showed that every cancer cell line acquired invasive potential in coculture with stromal cell lines and the cyclooxygenase-2 inhibitor suppressed this phenomenon by downregulating the matrix metalloproteinase-2 expression of stromal cells. In conclusion, these findings suggest that matrix metalloproteinase-2 expression in stromal cells can be a high-risk indicator for recurrence in patients with stage II colon cancer.

Occurrence and prognostic value of circumferential resection margin involvement for patients with rectal cancer

BACKGROUND AND AIM

Total mesorectal excision (TME) was advocated owning to the reduction in local failure, while deficiency in pathologic details limited monitoring of surgical quality assurance. Here, we aimed to examine circumferential resection margin (CRM) by large tissue slice, discussing its rule in occurrence and relationship with prognosis, thus providing proof for the adoption of TME principles and the application of adjuvant therapy.

MATERIALS AND METHODS

Specimens of 106 patients with rectal cancer, who underwent potentially curative resection from December 2001 to September 2002, were examined. Follow-up data were collected.

RESULTS

Altogether, 2,068 mesorectal nodes were examined with 272 involved by tumor. CRM involvement (CRMI) was examined in 20 specimens. In these 20 cases, seven, nine, and four were caused by tumor infiltration, lymph node metastasis, and both, respectively. Occurrence of CRMI was more common for lower-located cancers while also statistically related to tumor differentiation, infiltration, and lymph node metastasis. The difference in local recurrence rate, general recurrence rate, disease-free survival rate, and overall survival rate between the group with CRMI and the group without were all proven to be significant.

CONCLUSIONS

Detailed pathologic examination, including status of CRM, is advocated since it provides accurate prognostic information. Surgeons could maximize the probability of cure by following the principle of TME. Preoperative adjuvant therapy was essential for advanced staged and lower-located lesions, which implied likelihood of CRMI.

Postoperative radiotherapy for stage IIIA rectal cancer: is it justified?

PURPOSE

Adjuvant radiotherapy is currently recommended for all node-positive rectal cancers to reduce local recurrence. This study evaluated if an adequate mesorectal excision can obviate the need for radiotherapy in early node-positive cancer.

METHODS

Stage IIIA rectal cancer patients were identified in a prospectively maintained database. Patients who received postoperative radiotherapy (radiotherapy) and those who did not (no radiotherapy) were compared for recurrence, survival, bowel function, and quality of life. Quality of life was assessed using the Short Form-36 Medical Outcomes Survey.

RESULTS

Eighty-six patients underwent proctectomy for T1-T2,N1 rectal cancers from 1978 to 2004. Patients receiving radiotherapy (n = 34) were younger and had a higher percentage of T1 tumors than patients who did not receive radiotherapy (n = 52). Other tumor characteristics, type of surgery, and number of involved lymph nodes were comparable. Estimated 5-year local recurrence was radiotherapy 3.4 percent and no radiotherapy 4.7 percent; distant recurrence was radiotherapy 13.5 percent and no radiotherapy 16.5 percent; and disease-specific mortality rates were similar 13.5 vs. 11.3 percent, for radiotherapy and no radiotherapy (all P > .05). Patients receiving radiotherapy had higher frequency of daytime bowel movements, urgency, and usage of pads and antidiarrheal medications. Age adjusted quality of life parameters were comparable between treatments.

CONCLUSION

Postoperative radiotherapy did not reduce recurrence or mortality. Function but not quality of life was adversely affected. Routine postoperative radiotherapy for Stage IIIA rectal cancer should be reconsidered.

Cost-effectiveness of adjuvant chemotherapy with uracil-tegafur for curatively resected stage III rectal cancer

Recently, the National Surgical Adjuvant Study of Colorectal Cancer in Japan, a randomised controlled trial of oral uracil-tegafur (UFT) adjuvant therapy for stage III rectal cancer, showed remarkable survival gains, compared with surgery alone. To evaluate value for money of adjuvant UFT therapy, cost-effective analysis was carried out. Cost-effectiveness analysis of adjuvant UFT therapy was carried out from a payer's perspective, compared with surgery alone. Overall survival and relapse-free survival were estimated by Kaplan-Meier method, up to 5.6 years from randomisation. Costs were estimated from trial data during observation. Quality-adjusted life-years (QALYs) were calculated using utility score from literature. Beyond observation period, they were simulated by the Boag model combined with the competing risk model. For 5.6-year observation, 10-year follow-up and over lifetime, adjuvant UFT therapy gained 0.50, 0.96 and 2.28 QALYs, and reduced costs by $2457, $1771 and $1843 per person compared with surgery alone, respectively (3% discount rate for both effect and costs). Cost-effectiveness acceptability and net monetary benefit analyses showed the robustness of these results. Economic evaluation of adjuvant UFT therapy showed that this therapy is cost saving and can be considered as a cost-effective treatment universally accepted for wide use in Japan.

The impact of T and N stage on long-term survival of rectal cancer patients in the community

BACKGROUND AND OBJECTIVES

Use of the TNM staging system has been encouraged for rectal cancer patients. This study examined the impact of T and N stages on long-term survival as well as the performance of associated risk classification systems.

METHODS

Patients who underwent surgery for rectal adenocarcinoma from 1988 to 2004 were identified in the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier survival analysis was performed for subgroups of patients defined by T and N stage.

RESULTS

For the overall population of 30,826 patients, both T and N stage significantly impacted overall survival (P < 0.001). N stage variably affected survival for subgroups of patients based on T stage, whereas T stage significantly affected survival regardless of N stage. A previously developed risk classification system that assigns one of four risk levels outperformed AJCC group staging in this cohort. Based on long-term outcomes, a modified risk classification system was constructed which was highly prognostic for long-term overall survival (P < 0.001).

CONCLUSIONS

Rectal cancer patients experience widely varying survival rates based on extent of disease. A new risk classification system is proposed that provides better prognostic information than AJCC group staging, suggesting current rectal cancer staging systems may be improved with appropriate revisions.

Adjuvant therapy for completely resected stage II colon cancer

BACKGROUND

Colon cancer is potentially curable by surgery. Although adjuvant chemotherapy benefits patients with stage III disease, there is uncertainty of such benefit in stage II colon cancer. A systematic review of the literature was performed to better define the potential benefits of adjuvant therapy for patients with stage II colon cancer.

OBJECTIVES

To determine the effects of adjuvant therapy on overall survival and disease-free survival in patients with stage II colon cancer.

SEARCH STRATEGY

Ovid MEDLINE (1986-2007), EMBASE (1980-2007), and EBM Reviews - Cochrane Central Register of Controlled Trials ( to 2007) were searched using the medical headings "colonic neoplasms", "colorectal neoplasms", "adjuvant chemotherapy", "adjuvant radiotherapy" and "immunotherapy", and the text words "colon cancer" and "colonic neoplasms". In addition, proceedings from the annual meetings of the American Society of Clinical Oncology and the European Society of Medical Oncology (1996 to 2004) as well as personal files were searched for additional information.

SELECTION CRITERIA

Randomized trials or meta-analyses containing data on stage II colon cancer patients undergoing adjuvant therapy versus surgery alone.

DATA COLLECTION AND ANALYSIS

:Three reviewers summarized the results of selected studies. The main outcomes of interest were overall and disease-free survival, however, data on toxicity and treatment delivery were also recorded.

MAIN RESULTS

With regards to the effect of adjuvant therapy on stage II colon cancer, the pooled relative risk ratio for overall survival was 0.96 (95% confidence interval 0.88, 1.05). With regards to disease-free survival, the pooled relative risk ratio was 0.83 (95% confidence interval 0.75, 0.92).

AUTHORS' CONCLUSIONS

Although there was no improvement in overall survival in the pooled analysis, we did find that disease-free survival in patients with stage II colon cancer was significantly better with the use of adjuvant therapy. It seems reasonable to discuss the benefits of adjuvant systemic chemotherapy with those stage II patients who have high risk features, including obstruction, perforation, inadequate lymph node sampling or T4 disease. The co-morbidities and likelihood of tolerating adjuvant systemic chemotherapy should be considered as well. There exists a need to further define which high-risk features in stage II colon cancer patients should be used to select patients for adjuvant therapy. Also, researchers must continue to search for other therapies which might be more effective, shorter in duration and less toxic than those available today.

Orthotopic implantation mouse model and cDNA microarray analysis indicates several genes potentially involved in lymph node metastasis of colorectal cancer

In colorectal cancer (CRC) patients, metastasis to the regional lymph node (LN) is an important first step in the dissemination of cancers. To identify the genes possibly involved in LN metastasis of CRC, we analyzed LN metastases in an orthotopic implantation mouse model with 22 CRC cell lines using Matrigel, an extracellular matrix protein derived from mice sarcoma, and combined the data with gene expression profiles of cDNA microarray of those cell lines. With this implantation analysis, the incidence of LN metastasis was 60% in 228 orthotopically implanted mice and varied from 100% to 0% among the cell lines. KM12c and Clone A showed LN metastasis in all orthotopically implanted mice, but DLD-1, HCT-8, and SW948 did not show LN metastases at all. In contrast, the incidence of liver and lung metastasis in 22 CRC cell lines was 13% and 1%, respectively. Combining those data with cDNA microarray in vitro, we isolated 636 genes that were differentially expressed depending on the incidence of LN metastasis. Among those genes, the expression level of ring finger protein 125 (RNF125), previously known as an E3 ubiquitin ligase in T cell activation, was significantly different between primary tumors in Stage III CRC patients with LN metastasis and Stage II patients without LN metastasis. In conclusion, the orthotopic implantation mice model with Matrigel was useful, and we isolated candidate genes such as RNF125 that possibly play an important role in LN metastasis of CRC cells.

Quality of life after rectal resection and multimodality therapy

Modern management of locally advanced rectal cancer requires a multimodality approach. This includes radical surgery, pelvic radiotherapy, and systemic chemotherapy. It can require a permanent colostomy and result in significant bowel, sexual, and urinary dysfunction. In order to determine the effectiveness of various multimodality regimens it is important to not only assess conventional oncologic outcomes but also the impact on patient's quality of life.

In vivo biomarkers for targeting colorectal neoplasms

Colorectal carcinoma continues to be a leading cause of cancer morbidity and mortality despite widespread adoption of screening methods. Targeted detection and therapy using recent advances in our knowledge of in vivo cancer biomarkers promise to significantly improve methods for early detection, risk stratification, and therapeutic intervention. The behavior of molecular targets in transformed tissues is being comprehensively assessed using new techniques of gene expression profiling and high throughput analyses. The identification of promising targets is stimulating the development of novel molecular probes, including significant progress in the field of activatable and peptide probes. These probes are being evaluated in small animal models of colorectal neoplasia and recently in the clinic. Furthermore, innovations in optical imaging instrumentation are resulting in the scaling down of size for endoscope compatibility. Advances in target identification, probe development, and novel instruments are progressing rapidly, and the integration of these technologies has a promising future in molecular medicine.

New anti-proliferative agent, MK615, from Japanese apricot “Prunus mume” induces striking autophagy in colon cancer cells in vitro

AIM: To investigate the anti-neoplastic effects of MK615, an extract from the Japanese apricot (Prunus mume), against colon cancer cells.

METHODS: Three colon cancer cell lines, SW480, COLO, and WiDr, were cultured with MK615. Growth inhibition was evaluated by cell proliferation assay and killing activity was determined by lactate dehydrogenase assay. Induction of apoptosis was evaluated by annexin V flow cytometry. Morphological changes were studied by light and electron microscopy, and immunofluorescence staining with Atg8.

RESULTS: MK615 inhibited growth and lysed SW480, COLO and WiDr cells in a dose-dependent manner. Annexin V flow cytometry showed that MK615 induced apoptosis after 6 h incubation, at which point the occurrence of apoptotic cells was 68.0%, 65.7% and 64.7% for SW480, COLO, and WiDr cells, respectively. Light and electron microscopy, and immunofluorescence staining with Atg8 revealed that MK615 induced massive cytoplasmic vacuoles (autophagosomes) in all three cell lines.

CONCLUSION: MK615 has an anti-neoplastic effect against colon cancer cells. The effect may be exerted by induction of apoptosis and autophagy.