Colon cancer screening: Where have we come from and where do we go?

Repurposing of niclosamide as a STAT3 inhibitor to enhance the anticancer effect of chemotherapeutic drugs in treating colorectal cancer

AIMS

Colorectal cancer (CRC) is the third most common cancer worldwide. Mutation of various cell signaling molecules or aberrant activation of signaling pathways leads to poor response to chemotherapy in CRC. Signal transducer and activator of transcription protein 3 (STAT3) is an important signaling molecule, which plays crucial roles in regulating cell survival and growth. In this study, the potentitation of chemotherapy by putative STAT3 inhibitors for treating CRC was investigated.

MAIN METHODS

A few putative STAT3 inhibitors were investigated. Niclosamide, originally indicated for the treatment of tapeworm infection, was chosen for further investigation in five CRC cell lines (HCT116, HT29, HCC2998, LoVo and SW480). Western blot analysis was used to evaluate the expression of STAT3/phospho-STAT3 and its downstream targets. Sulforhodamine B assay was used to evaluate the cytotoxicity of drug combinations. Flow cytometric assays were used to investigate the apoptotic and cell cycle effect.

KEY FINDINGS

Niclosamide was found to inhibit expression and activation of STAT3 in a concentration- and time-dependent manner, thereby downregulating STAT3 downstream targets including survivin and cyclin-D1 to induce apoptosis and cell cycle arrest. When combined with niclosamide or specific STAT3 inhibitor (C188-9), the cytotoxicity and DNA damage response from SN38 (the active metabolite from irinotecan) were significantly enhanced. The sequential exposure of SN38 followed by niclosamide was found to be the most potent treatment sequence for the drug combination.

SIGNIFICANCE

Niclosamide represents a promising candidate for repurposing to potentiate the anticancer activity of chemotherapeutic drugs.

Niclosamide inhibition of STAT3 synergizes with erlotinib in human colon cancer

Niclosamide, an anthelmintic drug approved by the US Food and Drug Administration against cestodes, is used to treat tapeworm infection. In this study, we show that niclosamide can potentially inhibit signal transducer and activator of transcription 3 (STAT3) in colon cancer cell lines. Combined inhibition of epidermal growth factor receptor and STAT3 by erlotinib and niclosamide synergistically induces apoptosis and antiproliferation in colon cancer cell lines. Our findings suggest that erlotinib and niclosamide combination provides an effective therapeutic approach to improving the prognosis of colon cancer.

Chemopreventive effect of chalcone derivative, L2H17, in colon cancer development

BACKGROUND

Colon cancer is the third most commonly diagnosed cancer and the second leading cause of cancer mortality worldwide. Chalcone and its derivatives are reported to exhibit anti-cancer effects in several cancer cell lines, including colon cancer cells. In addition, chalcones have advantages such as poor interaction with DNA and low risk of mutagenesity. In our previous study, a group of chalcone derivatives were synthesized and exhibited strong anti-inflammatory activities. In this study, we evaluated the anti-cancer effects of the chalcone derivative, L2H17, in colon cancer cells.

METHODS

The cytotoxicities of L2H17 on various colon cancer cell lines were investigated by MTT and clonogenic assay. Cell cycle and apoptosis analysis were performed to evaluate the molecular mechanism of L2H17-mediated inhibition of tumor growth. Also, scratch wound and matrigel invasion experiments were performed to estimate the cell migration and invasion after L2H17 treatment. Finally, we observed the anti-colon cancer effects of L2H17 in vivo.

RESULTS

Our data show that compound L2H17 exhibited selective cytotoxic effect on colon cancer cells, via inducing G0/G1 cell cycle arrest and apoptosis in CT26.WT cells. Furthermore, L2H17 treatment decreased cell migration and invasion of CT26.WT cells. In addition, L2H17 possessed marked anti-tumor activity in vivo. The molecular mechanism of L2H17-mediated inhibition of tumor promotion and progression were function through inactivated NF-κB and Akt signaling pathways.

CONCLUSIONS

All these findings show that L2H17 might be a potential growth inhibitory chalcones derivative for colon cancer cells.

Assessment of a rapid referral pathway for suspected colorectal cancer in Madrid

OBJECTIVE

To assess the results achieved with a rapid referral pathway for suspected colorectal cancer (CRC), comparing with the standard referral pathway.

METHODS

Three-year audit of patients suspected of having CRC routed via a rapid referral pathway, and patients with CRC routed via the standard referral pathway of a health care district serving a population of 498,000 in Madrid (Spain). Outcomes included referral criteria met, waiting times, cancer diagnosed and stage of disease.

RESULTS

Two hundred and seventy-two patients (mean age 68.8 years, SD 14.0; 51% male) were routed via the rapid referral pathway for colonoscopy. Seventy-nine per cent of referrals fulfilled the criteria for high risk of CRC. Fifty-two cancers were diagnosed: 26% Stage A (Astler-Coller), 36% Stage B, 24% Stage C and 14% Stage D. Average waiting time to colonoscopy for the rapid referral patients was 18.5 days (SD 19.1) and average waiting time to surgery was 28.6 days (SD 23.9). Colonoscopy was performed within 15 days in 65% of CRC rapid referral patients compared to 43% of standard pathway patients (P = 0.004). Overall waiting time for patients with CRC in the rapid referral pathway was 52.7 days (SD 32.9); while for those in the standard pathway, it was 71.5 days (SD 57.4) (P = 0.002). Twenty-six per cent Stage A CRC was diagnosed in the rapid referral pathway compared to 12% in the standard pathway (P < 0.001).

CONCLUSION

The rapid referral pathway reduced waiting time to colonoscopy and overall waiting time to final treatment and appears to be an effective strategy for diagnosing CRC in its early stages.

The role of physician reminders in faecal occult blood testing for colorectal cancer screening

BACKGROUND

Colorectal cancer screening in the form of faecal occult blood (FOB) testing can significantly reduce the burden of this disease and has been used as early as the 1970s. Effective involvement of GPs along with reminding physicians prior to seeing a patient may improve uptake.

OBJECTIVE

This article is a systematic review of published literature examining the uptake of FOB testing after physician reminders as part of the colorectal cancer screening process.

METHODS

Electronic databases were searched from January 1975 to October 2010. All studies comparing physician reminders (Rem) with controls (NRem) were identified. A meta-analysis was performed to obtain a summary outcome.

RESULTS

Five comparative studies involving 25 287 patients were analyzed. There were 12 641 patients were in the Rem and 12 646 in the NRem group. All five studies obtained a higher percentage uptake when physician reminders were given. However, in only two of the studies were the percentage uptake significantly higher. There was significant heterogeneity among trials (I2 = 95%). The combined increase in FOB test uptake was not statistically significant (random effects model: risk difference = 6.6%, 95% CI: -2-14.7%; z = 1.59, P = 0.112).

CONCLUSION

Reminding physicians about those patients due for FOB testing may not improve the effectiveness of a colorectal cancer screening programme. Further studies are required and should focus on areas where there is a lower baseline uptake and areas with high levels of deprivation.

Colon cancer screening update and management of the malignant polyp

Colorectal carcinoma is common, but screening for this cancer has found less acceptance with the public than screening for breast, prostate, and cervical cancer. Available methods include fecal occult blood tests (FOBTs), flexible sigmoidoscopy (FOS), double-contrast barium enema, colonoscopy, computed tomographic colography, and fecal DNA. Evaluation of these options demonstrates that colonoscopy at ages 55 and 65 offers the best combination of reduction in colorectal cancer at the lowest cost. However, when compliance with screening recommendations is very high, costs are high, and the proportion of cancers arising from adenomas is low, the combination of FOS and FOBT is most cost effective. Malignant polyps look friable and irregular and feel hard. Sessile malignant polyps need to be treated by formal resection. Patients with pedunculated polyps with favorable histology (clear margin, well or moderately differentiated, no lymphovascular invasion) can be observed, and those whose polyps show unfavorable histology should have the polyp-bearing segment of colon resected along with its draining lymph nodes.

An Overview of Colorectal Cancer Screening

Colorectal cancer ranks highly amongst all cancer sites in incidence and contributes to a substantial number of cancer related deaths in the United Kingdom. However, screening of average risk individuals has been shown to reduce both disease associated mortality and incidence. This paper provides an overview of both current and future screening methods for colorectal cancer, as well as current practice for screening in both average and high risk individuals.

RAGE activation by S100P in colon cancer stimulates growth, migration, and cell signaling pathways

PURPOSE

Colon cancer is the third most prevalent cancer in the United States. However, the molecular mechanisms involved in the development and progression of colon cancer are incompletely understood. This study was initiated to explore the potential role of the receptor for advanced glycation end-products and S100P in modulation of key properties of human colon cancer cells.

METHODS

Western blot, reverse transcription-polymerase chain reaction, and quantitative polymerase chain reaction were performed for detection of the receptor for advanced glycation end-products and S100P in colon cancer and matched normal colon. The influence of exogenously added S100P was analyzed on SW480 colon cancer cell line proliferation, migration, phosphorylation of mitogen activated protein kinases, and NFkappaB activation. To identify the mechanisms involved in these responses, coimmunoprecipitation examining the S100P/Receptor for advanced glycation end-products interaction and the effects of receptor for advanced glycation end-products inhibition in this interaction were analyzed.

RESULTS

Although the receptor for advanced glycation end-products was present in normal and malignant colon specimens, only the malignant specimens expressed S100P. Treatment of SW480 cells with S100P increased proliferation and cell migration. Addition of exogenous S100P stimulated both ERK1/2 phosphorylation and NFkappaB activity. The interaction between S100P and the receptor for advanced glycation end-products was demonstrated by coimmunoprecipitation of these molecules from SW480 cells. Antagonism of the receptor for advanced glycation end-products blocked this interaction and the biologic effects of S100P on these cells.

CONCLUSIONS

These data indicate that S100P is expressed at greater levels in colon cancer than matched normal tissue and that S100P stimulates colon cancer cell growth, migration, Erk phosphorylation, and NFkappaB activation in vitro, suggesting that this ligand/receptor pair may be targeted for the development of new therapies.

Yttrium-90 Microsphere Therapy for Hepatic Malignancy: Devices, Indications, Technical Considerations, and Potential Complications

Management of hepatic malignancies is a ubiquitous medical problem. Surgical resection of primary or metastatic liver cancer, with or without adjuvant chemotherapy, is the most effective method for enhancing survival; however, hepatic malignancies in the vast majority of patients are unresectable both at initial manifestation and at recurrence. In these patients, palliative cytoreductive therapies may help to retard tumor progression and therefore favorably alter the course of the disease. Since hepatic neoplasms are principally supplied by the hepatic artery, various arterially delivered cytotoxic agents have been developed to achieve these objectives. Recently, the Food and Drug Administration approved the transarterial administration of yttrium-90 microspheres for liver-directed therapy. Effective use of these devices requires knowledge of the accumulated clinical experience and a dedicated multidisciplinary effort to ensure optimal outcomes and avoid therapy-specific life-threatening complications.