Colorectal cancer

Loss of p27Kip1 leads to expansion of CD4+ effector memory T cells and accelerates colitis-associated colon cancer in mice with a T cell lineage restricted deletion of Smad4

The cyclin-dependent kinase inhibitor p27^Kip1 is a tumor suppressor whose intrinsic activity in cancer cells correlates with tumor aggressiveness, invasiveness, and impaired tumor cell differentiation. Here we explore whether p27^Kip1 indirectly influences tumor progression by restricting expansion and survival of effector memory T cell (T_EM) populations in a preclinical model of spontaneous colitis-associated colorectal cancer (CAC). We show mRNA and protein expression of p27^Kip1 to be significantly decreased in the colons of mice with a T cell-restricted deletion of the TGF-β intermediate, SMAD4 (Smad4^TKO). Loss of p27^Kip1 expression in T cells correlates with the onset of spontaneous CAC in Smad4^TKO mice by 8 months of age. This phenotype is greatly accelerated by the introduction of a germline deletion of CDKN1b (the gene encoding p27^Kip1) in Smad4^TKO mice (Smad4^TKO/p27^Kip1-/-, DKO). DKO mice display colon carcinoma by 3 months of age and increased mortality compared to Smad4^TKO. Importantly, the phenotype in DKO mice is associated with a significant increase in the frequency of effector CD4 T cells expressing abundant IFN-γ and with a concomitant decrease in Foxp3⁺ regulatory T cells, both in the intestinal mucosa and in the periphery. In addition, induction of inflammatory mediators (IFN-γ, TNF-γ, IL-6, IL-1β, iNOS) and activation of Stat1, Stat3, and IκB is also observed in the colon as early as 1–2 months of age. Our data suggest that genomic alterations known to influence p27^Kip1 abundance in gastrointestinal cancers may indirectly promote epithelial malignancy by augmenting the production of inflammatory mediators from a spontaneously expanding pool of T_EM cells.

MicroRNA-199b Deregulation Shows a Strong SET-Independent Prognostic Value in Early-Stage Colorectal Cancer

The endogenous PP2A inhibitor SET Nuclear Proto-Oncogene (SET) has been reported to play oncogenic roles and determines poor outcomes in colorectal cancer (CRC). Our group previously showed that miR-199b is deregulated in metastatic CRC, and reduced the cell viability and enhanced the sensitivity of CRC cells to standard induction chemotherapy drugs, mainly through direct negative SET regulation. Clinically, miR-199b downregulation was identified as the molecular mechanism responsible for SET overexpression in around half of metastatic CRC patients. However, the potential clinical value of miR-199b in early-stage CRC remains totally unknown. Thus, here we explored the expression levels of this microRNA in a cohort of 171 early-stage CRC patients using real-time polymerase chain reactions. MiR-199b downregulation was found in 21.6% of cases (37 out of 171) and was significantly associated with those patients with a worse Eastern Cooperative Oncology Group (ECOG) status (p = 0.045). Moreover, miR-199b downregulation predicted shorter overall (p < 0.001) and progression-free survival (p = 0.015). As expected, we next immunohistochemically analyzed SET, observing that it was significantly associated with miR-199b in our cohort. However, multivariate analyses showed that miR-199b was an independent biomarker of poor outcomes in early-stage CRC with a predictive value stronger than SET. In conclusion, our results highlight the potential clinical usefulness of miR-199b and suggest that it could represent a novel molecular target in this disease.

Novel chemotherapeutic agent, FND-4b, activates AMPK and inhibits colorectal cancer cell proliferation

Colorectal cancer (CRC) is the second leading cause of cancer deaths in the US with the majority of deaths due to metastatic disease. Current chemotherapeutic regimens involve highly toxic agents, which limits their utility; therefore, more effective and less toxic agents are required to see a reduction in CRC mortality. Novel fluorinated N,N’-diarylureas (FND) were developed and characterized by our group as potent activators of adenosine monophosphate-activated kinase (AMPK) that inhibit cell cycle progression. The purpose of this study was to determine the effect of a lead FND compound, FND-4b, either alone or combined with PI-103 (a dual PI3K/mTOR inhibitor) or SN-38 (active metabolite of irinotecan) on cell cycle arrest and apoptosis of CRC cell lines (both commercially-available and novel lines established from our patient population). Treatment with FND-4b for 24h resulted in a marked induction of phosphorylated AMPK expression and a concomitant reduction in markers of cell proliferation, such as cyclin D1, in all CRC cell lines. Apoptosis was also notably increased in CRC cells treated with FND-4b. Regardless of the genetic profile of the CRC cells, FND-4b treatment alone resulted in decreased cell proliferation. Moreover, the combination of FND-4b with PI-103 resulted in increased cell death in all cell lines, while the combination of FND-4b with SN-38 resulted in increased cell death in select cell lines. Our findings identify FND-4b, which activates AMPK at micromolar concentrations, as a novel and effective inhibitor of CRC growth either alone or in combination with PI-103 and SN-38.

MicroRNA-193a-3p suppresses the colorectal cancer cell proliferation and progression through downregulating the PLAU expression

Background

Colorectal cancer (CRC) is one of the leading causes of cancer-related death in China. Dysregulation of microRNAs (miRNAs) is involved in cancer development and progression. Our previous study showed an inverse relationship between miR-193a-3p expression and the prognosis of CRC. However, the exact biological functions of miR-193a-3p in CRC are still poorly understood. This study aimed to explore the role and mechanism of miR-193a-3p in CRC.

Methods

Real-time PCR and Western blotting were used to examine the expression levels of RNA and protein, respectively. A dual luciferase assay was performed to validate predicted targets of miR-193a-3p. Loss and gain-of-function studies were carried out to reveal the effects and potential mechanism of the miR-193a-3p in the proliferation, metastasis and angiogenesis of CRC cells.

Results

The expression levels of miR-193a-3p in human CRC cell lines were significantly decreased compared with that in normal colonic epithelium cell line. Furthermore, plasminogen activator urokinase (PLAU) was validated as a direct target gene of miR-193a-3p. Over-expression of miR-193a-3p inhibited proliferation, migration and angiogenesis of HT-29 cell, whereas forced expression of PLAU could rescue the inhibitory effects.

Conclusion

miR-193a-3p might inhibit CRC cell growth, migration and angiogenesis partly through targeting PLAU. MiR-193a-3p/PLAU axis might provide a potent therapeutic opportunity for aggressive CRC.

Efficacy and safety of trifluridine/tipiracil in third-line and beyond for the treatment of patients with metastatic colorectal cancer in routine clinical practice: patterns of use and prognostic nomogram

INTRODUCTION

Trifluridine/tipiracil combination has shown a benefit over placebo in the treatment of patients with chemorefractory metastatic colorectal cancer (mCRC). We evaluated the efficacy and safety of this combination in the real-life setting at eight Galician centers in Spain.

PATIENTS AND METHODS

This is a retrospective study of a cohort of patients with mCRC in treatment with trifluridine/tipiracil within usual clinical practice who have been previously treated or are not considered candidates for treatment with available therapies.

RESULTS

A total of 160 mCRC patients were included. Our data showed that 11.9% of patients achieved disease control. Median progression-free survival was 2.75 months; at 5.66 months follow-up, median overall survival was 7.94 months. Asthenia and neutropenia (48.1% both) were the most frequent adverse events. Overall survival was lower in patients with ECOG 2, multiple metastatic sites, platelets count 350,000/µl, alkaline phosphatase > 500 IU/l, and carcinoembryonic antigen > 10 ng/ml.

CONCLUSION

The results of this study confirm the efficacy and safety of trifluridine/tipiracil in chemorefractory mCRC patients. However, patients in clinical practice differ from patients in clinical trials. Due to this, prognostic factors have special importance to offer the best therapeutic approach.

Deregulation of SET is Associated with Tumor Progression and Predicts Adverse Outcome in Patients with Early-Stage Colorectal Cancer

SET nuclear proto-oncogene (SET) deregulation is a novel molecular target in metastatic colorectal cancer (CRC). However, its role in CRC progression and its potential clinical impact in early-stage CRC patients remain unknown. Here, we studied the biological effects of SET on migration using wound-healing and transwell assays, and anchorage-independent cell growth using soft agar colony formation assays after ectopic SET modulation. SET was analyzed by immuno-staining in 231 early-stage CRC patients, and miR-199b expression was quantified by real-time PCR in a set of CRC patients. Interestingly, SET enhances cell migration, markedly affects the colony-forming ability, promotes epithelial to mesenchymal transition, and induces the expression of the MYC proto-oncogene (c-MYC) in CRC cells. SET overexpression was detected in 15.4% of cases and was associated with worse Eastern Cooperative Oncology Group (ECOG) status (p = 0.021) and relapse in stage-II CRC patients (p = 0.008). Moreover, SET overexpression predicted shorter overall survival (p < 0.001) and time to metastasis (p < 0.001), and its prognostic value was particularly evident in elderly patients. MiR-199b downregulation was identified as a molecular mechanism to deregulate SET in patients with localized disease. In conclusion, SET overexpression is a common alteration in early-stage CRC, playing an oncogenic role associated with progression and aggressiveness, and portends a poor outcome. Thus, SET emerges as a novel potential molecular target with clinical impact in early-stage in CRC.

Downregulation of microRNA-199b predicts unfavorable prognosis and emerges as a novel therapeutic target which contributes to PP2A inhibition in metastatic colorectal cancer

The tumor suppressor microRNA-199b (miR-199b) is a negative SET regulator associated with poor outcome in some human cancers. However, its expression levels as well as potential biological and clinical significance in colorectal cancer (CRC) remain completely unexplored. The PP2A inhibitor SET has shown promising therapeutic and clinical implications in metastatic CRC (mCRC) but the molecular mechanisms underlying SET deregulation are currently unknown. We show here miR-199b downregulation in 4 out of 5 CRC SET-overexpressing cell lines and its inverse correlation with SET overexpression in CRC patients. Moreover, miR-199b led to PP2A activation through a direct SET inhibition, impaired cell viability and enhanced oxaliplatin sensitivity in CRC cells. MiR-199b was found downregulated in 25% of cases, and associated with lymph metastasis (p = 0.049), presence of synchronous metastasis at diagnosis (p = 0.026) and SET overexpression (p < 0.001). Furthermore, low miR-199b levels determined shorter overall (p < 0.001), progression-free survival (p = 0.003) and predicted clinical benefit to oxaliplatin treatment. The miR-199b prognostic impact was particularly evident in both younger and KRAS wild-type subgroups. Multivariate analyses confirmed its independent prognostic impact. Altogether, our results show that miR-199b is a tumor suppressor whose downregulation independently determines worse outcome and emerges as a potential contributing mechanism to inhibit PP2A via SET overexpression in a subgroup of mCRC patients.

Tumor-suppressive miR-26a and miR-26b inhibit cell aggressiveness by regulating FUT4 in colorectal cancer

Metastasis is a multistep molecular network process, which is the major cause of death in patients with colorectal cancer (CRC). MicroRNAs (miRNAs) play pivotal roles in tumorigenesis as either tumor suppressors or oncogenes. Increased expression of fucosyltransferase4 (FUT4) has been reported to be associated with the invasive and metastatic properties of CRC. Here to identify potential key miRNAs and their target genes for colorectal cancer (CRC), we compared miRNA expression profiles between metastatic CRC cell SW620 and primary CRC cell SW480. Microarray analysis revealed that there were 85 differentially expressed miRNAs in SW620 cells with highly metastatic potential compared to SW480 cells with lowly metastatic potential. The expression of miR-26a and miR-26b were lower in SW620 cells than in SW480 cells, as well as downregulated in tumor tissues than in adjacent normal tissues of CRC patients. By applying bioinformatic approaches for the prediction of miRNA targeting 3'-UTR of FUT4, we identified FUT4 as one of the miR-26a/26b-targeted genes, while the expression of the target gene exhibited patterns opposite to that of miR-26a/26b in CRC cell lines, tumor tissues and corresponding adjacent tissues. Forced miR-26a/26b expression affected migratory behavior of CRC cells and FUT4 expression, while altered expression of FUT4 in CRC cell lines modulated progression upon transfection with miR-26a/26b mimic or inhibiter. FUT4 also regulated directly aggressiveness of SW620 and SW480 cells. Moreover, statistical analyses revealed that low miR-26a/26b levels and high expression of FUT4 were positively correlated with poor overall survival. The identified CRC-restricted miR-26a and miR-26b might be implicated in cancer progression via their target gene FUT4, suggesting their potential usage in CRC treatment.

Phase II study of the Multikinase inhibitor of angiogenesis, Linifanib, in patients with metastatic and refractory colorectal cancer expressing mutated KRAS

Background Targeting angiogenesis in advanced colorectal cancer (CRC) has been one of the many factors prolonging survival. Bevacizumab was the first agent to demonstrate this, but even after progression on bevacizumab, continued VEGF-inhibition continues to improve survival. Combining epidermal growth factor receptor monoclonal antibodies with standard frontline therapies have also improved clinical outcomes, yet the improved benefit is not observed in patients with mutant KRAS. Thus, an unmet medical need exists to develop additional therapeutic options for patients with KRAS mutant CRC. Methods Patients received the anti-angiogenic agent linifanib at the recommended phase II dose of 17.5 mg. Primary endpoint was objective response rate (ORR), with a goal of 10%. Secondary endpoints were progression-free survival (PFS), overall survival (OS), and safety. Simon's optimal two-stage design was used to assess futility. Linifanib was considered inactive if two or fewer patients among the first 30 achieved an objective response. Results Thirty patients were enrolled on study. Grade 3 treatment-related toxicities occurring in at least two patients were fatigue, hypertension, proteinuria, diarrhea, nausea, oral pain, vomiting, thrombocytopenia, and arthralgia. Although no responses were observed, 63.5% of patients achieved stable disease. The median PFS and OS were 4.7 months and 9.5 months, respectively. Stopping rules for lack of clinical efficacy led to study closure. Conclusion Despite observing zero responses, a majority of patients had stable disease and eight patients had stable disease lasting longer than 5 months. These results suggest that linifanib has some anti-tumor activity in KRAS mutant metastatic and refractory CRC.

A novel antimetabolite: TAS-102 for metastatic colorectal cancer

TAS-102 is a new oral anti-tumor drug, composed of a thymidine-based nucleoside analog (trifluridine: FTD) and a thymidine phosphorylase inhibitor (tipiracil hydrochloride: TPI). TAS-102 has been shown to significantly improve overall survival and progression-free survival in patients with refractory metastatic colorectal cancer (mCRC) in placebo-controlled randomized phase II and III trials. The current review summarizes mechanisms of action, pharmacokinetics/dynamics and preclinical and clinical data of TAS-102 in colorectal cancer. TAS-102 is a new salvage-line treatment option for patients with mCRC. TAS-102 is well tolerated and has great potential in future clinical drug combination therapies.

Clinical Implication of UGT1A1 Promoter Polymorphism for Irinotecan Dose Escalation in Metastatic Colorectal Cancer Patients Treated with Bevacizumab Combined with FOLFIRI in the First-line Setting

PURPOSE: This study aimed to identify the efficacy and toxicity of the FOLFIRI regimen (fluorouracil, leucovorin, and irinotecan) with irinotecan dose escalation plus bevacizumab as first-line chemotherapy for metastatic colorectal cancer (mCRC) via UGT1A1 genotyping. METHODS: We administered bevacizumab plus FOLFIRI with irinotecan dose escalation to treat 70 mCRC patients. The UGT1A1 *1/*1 and *1/*28 genotypes started with a 180-mg/m² dose of irinotecan, and UGT1A1 *28/*28 genotype started with a dose of 120 mg/m². The dose of irinotecan was escalated at increasing intervals of 20 to 30 mg/m² until grade 3/4 adverse events (AEs) occurred. The clinical response rate, toxicity, and survival were analyzed. RESULTS: The clinical response and disease control rates of mCRC patients treated with FOLFIRI plus bevacizumab were significantly better in patients with UGT1A1 *1/*1 and *1/*28 genotypes than in patients with UGT1A1 *28/*28 (P = .006 and P < .001, respectively). Grade 3/4 AEs were significantly more common in mCRC patients with the UGT1A1 *28/*28 genotype (P < .001). Progression-free survival was significantly higher in UGT1A1 *1/*1 and *1/*28 patients (P = .002). mCRC patients who underwent metastasectomy achieved better overall survival than those who did not undergo metastasectomy (P = .015). CONCLUSIONS: Our study showed that mCRC patients with UGT1A1 *1/*1 and *1/*28 genotypes could receive escalated doses of irinotecan to obtain a more favorable clinical outcome without significant AEs.

FOXQ1 mediates the crosstalk between TGF-β and Wnt signaling pathways in the progression of colorectal cancer

A wide variety of signaling transduction pathways contribute to tumorigenesis. Forkhead box Q1 (FOXQ1) is a member of the forkhead transcription factor family and its upregulation is closely correlated with tumor progression and prognosis of multiple cancer types, including colorectal cancer. However, the molecular mechanisms by which FOXQ1 promotes tumorigenesis, especially cancer cell invasion and metastasis in colorectal cancer, have not been fully elucidated. In the present study, we demonstrate that FOXQ1 is overexpressed in colorectal tumor tissues and its expression level is closely correlated with the stage and lymph node metastasis of colorectal cancer. In in vitro cultured SW480 colorectal cancer cells, knockdown of FOXQ1 expression by small interfering RNA greatly diminished the aggressive tumor behaviors of SW480 cells, including angiogenesis, invasion, epithelial-mesenchymal transition, and resistance to chemotherapy drug-induced apoptosis. Further mechanistic investigation showed that FOXQ1 silencing prevents the nuclear translocation of β-catenin, thus reducing the activity of Wnt signaling. Moreover, TGF-β1 induced the expression of FOXQ1 as well as the migration and invasion of SW480 cells, which was partially prevented following knockdown of FOXQ1. Our results demonstrate that FOXQ1 plays a critical role during the tumorigenesis of colorectal cancer and is a mediator of the crosstalk between Wnt and TGF-β signaling pathways. Our findings provide further insight into the cancer biology of colorectal cancer and suggest that FOXQ1 is a potential therapeutic target for the development of therapies for colorectal cancer.

Common Symptoms and Distress Experienced Among Patients with Colorectal Cancer: A Qualitative part of Mixed Method Design

Background :

Colorectal cancer is one of the most common types of tumour in the world. Treatment side effects, together with the tumour symptoms, can result in a ‘symptom burden’. To understand the patient’s burden during chemotherapy treatment and plan effective symptom relief there is a need for more knowledge about the experience of symptoms from the patients’ perspective.

Objectives :

The study was designed to qualitatively identify and describe the most common symptoms among patients treated for colorectal cancer, and discover whether there are barriers to reporting symptoms.

Methods :

Thirteen Swedish patients diagnosed with colorectal cancer and treated with chemotherapy were interviewed face-to-face. The interviews were audio-taped and transcribed verbatim. The transcripts were analysed by following the principles of qualitative content analysis.

Results :

Nine symptoms/forms of distress were identified. Those most frequently expressed were fatigue, changed bowel habits, and affected mental well-being, closely followed by nausea, loss of appetite and neurological problems. Of particular note were the affected mental well-being, the magnitude of the neurological problems described, the symptoms related to skin and mucous membrane problems, and the reports of distressing pain. Barriers to symptom control were only expressed by the patients in passing and very vaguely.

Conclusion :

This study confirms other reports on most common symptoms in colorectal cancer. It also highlights the early onset of symptoms and provides data on less well-studied issues that warrant further study, namely affected mental well-being, the magnitude of the neurological problems and symptoms related to the skin and mucous membranes. Nurses need to be sensitive to the patients’ need presented and not only noting symptoms/distresses they have guidelines for.

Methylenetetrahydrofolate reductase polymorphism (677 C>T) predicts long time to progression in metastatic colon cancer treated with 5-fluorouracil and folinic acid

BACKGROUND AND AIMS

Fluoropyrimidine-based chemotherapy is the most common treatment for unresectable metastatic colorectal cancer (m-CRC). Therapy with 5-FU/folinic acid (FA) continues to be a standard treatment in developing countries. Pharmacogenomics allows the tailoring of cancer therapy to the patient. The polymorphism 677C>T of the methylenetetrahydrofolate reductase (MTHFR) gene seems to influence the effectiveness of treatment with 5-FU. We undertook this study to evaluate the frequency of MTHFR 677C>T polymorphism and its relationship to the time to progression (TTP) and overall survival (OS) in m-CRC treated with 5-FU/FA.

METHODS

The MTHFR 677C>T polymorphism was determined using PCR and allele-specific digestion. The clinical variables, TTP and OS, were analyzed in each case and compared between wild-type and variant polymorphic groups.

RESULTS

Among 34 patients (12 males and 22 females), we detected eight wild-type homozygous patients (CC; 24%), nine variant homozygous (TT; 26%), and 17 heterozygous (CT; 50%) individuals. The median TTP in patients with the MTHFR 677 CC, CT, and TT genotypes was 3.43, 4.77, and 4.80 months, respectively (p = 0.047, log rank). A longer TTP was observed in patients with polymorphic variant (CT and TT) compared with the wild-type homozygous patients (4.80 vs. 3.43 months; p = 0.031, log rank).

CONCLUSIONS

In this study, the frequency of the MTHFR 677C>T polymorphism is 50% among m-CRC Mexican patients. The results of this study appear to show that the presence of the MTHFR 677C>T polymorphism is associated with longer TTP and OS in m-CRC treated with 5-FU/FA.

Stem cells in clinical practice: applications and warnings

Stem cells are a relevant source of information about cellular differentiation, molecular processes and tissue homeostasis, but also one of the most putative biological tools to treat degenerative diseases. This review focuses on human stem cells clinical and experimental applications. Our aim is to take a correct view of the available stem cell subtypes and their rational use in the medical area, with a specific focus on their therapeutic benefits and side effects. We have reviewed the main clinical trials dividing them basing on their clinical applications, and taking into account the ethical issue associated with the stem cell therapy.

Lymphangiogenesis: A new player in cancer progression

Lymph node metastasis is the hallmark of colon cancer progression, and is considered one of the most important prognostic factors. Recently, there has been growing evidence that tumor lymphangiogenesis (formation of new lymphatic vessels) plays an important role in this process. Here, we review the latest findings of the role of lymphangiogenesis in colorectal cancer progression, and discuss its clinical application as a biomarker and target for new therapy. Understanding the molecular pathways that regulate lymphangiogenesis is mandatory to pave the way for the development of new therapies for cancer. In the future, tailored treatments consisting of combinations of chemotherapy, other targeted therapies, and anti-lymphangiogenesis agents will hopefully improve patient outcomes. This progression to the clinic must be guided by new avenues of research, such as the identification of biomarkers that predict response to treatment.

Fertility preservation for young women with rectal cancer--a combined approach from one referral center

BACKGROUND

Up to 6% of women with colorectal cancer are diagnosed in the reproductive age and are at risk for premature ovarian failure and infertility due to pelvic irradiation and chemotherapy.

STUDY DESIGN

Between 1997 and 2007, six women with rectal carcinoma were referred to the McGill Reproductive Center (Montreal, Canada) for fertility preservation. Following resection of their primary tumor, they were scheduled to undergo pelvic irradiation.

RESULTS

Five patients underwent laparoscopic ovarian lateral transposition before radiotherapy in order to relocate their ovaries outside the radiation field. A concomitant ovarian wedge resection was performed for ovarian cryopreservation. In two of these women, before dissecting the ovarian cortical tissue for cryopreservation, all visible follicles were aspirated. The sixth patient who had had low anterior resection underwent hormonal ovarian stimulation followed by oocyte retrieval and embryo vitrification.

CONCLUSIONS

Fertility preservation in women with rectal cancer is feasible. This includes laparoscopic ovarian transposition and cryopreservation of ovarian tissue, embryo, or oocyte.

Overexpression of OATP1B3 confers apoptotic resistance in colon cancer

Organic anion transporting polypeptide 1B3 (OATP1B3, SLCO1B3) is normally expressed in hepatocytes. In this study, we showed frequent overexpression of OATP1B3 in colorectal adenocarcinomas. Quantitative reverse transcription-PCR analysis of 17 colon tumors indicated tumoral overexpression of OATP1B3 by approximately 100-fold, compared with 20 normal colon samples (P < 0.0001). Using immunohistochemistry on a tissue microarray containing 93 evaluable colon tumor specimens, we detected immunostaining of OATP1B3 in 75 colon adenocarcinomas (81%) and no immunostaining in normal samples. To determine the functional effects of OATP1B3 expression on drug-induced apoptosis, we used camptothecin and oxaliplatin on a panel of colorectal cancer cell lines stably overexpressing OATP1B3. The results indicated that OATP1B3 overexpression enhanced cell survival in RKO, HCT-8, and HCT116(p53+/+) cells that harbor wild-type p53 but not in Caco-2 and HCT116(p53-/-) cells that lack p53, compared with the respective empty vector controls (P < 0.01). The terminal deoxynucleotidyl transferase-mediated nick-end labeling assay confirmed that HCT116(p53+/+) cells overexpressing OATP1B3 had significantly lower apoptotic levels compared with empty vector control (P < 0.001). The overexpression of OATP1B3 reduced the transcriptional activity of p53, with subsequent reductions in transcript and protein levels of its downstream transcription targets (P21WAF1 and PUMA). Overexpression of a point mutation (G583E) variant of OATP1B3 lacking transport activity did not confer an antiapoptotic effect or affect p53 transcriptional activity, suggesting that the antiapoptotic effect of OATP1B3 may be associated with its transport activity. Taken together, our results suggest that OATP1B3 overexpression in colorectal cancer cells may provide a survival advantage by altering p53-dependent pathways.

Irinophore C, a novel nanoformulation of irinotecan, alters tumor vascular function and enhances the distribution of 5-fluorouracil and doxorubicin

PURPOSE

To examine the antitumor effects of Irinophore C, a nanopharmaceutical formulation of irinotecan, on the tissue morphology and function of tumor vasculature in HT-29 human colorectal tumors.

EXPERIMENTAL DESIGN

Fluorescence microscopy was used to map and quantify changes in tissue density, tumor vasculature, hypoxia, and the distribution of Hoechst 33342, a perfusion marker, and the anticancer drug, doxorubicin. Noninvasive magnetic resonance imaging was used to quantify Ktrans, the volume transfer constant of a solute between the blood vessels and extracellular tissue compartment of the tumor, as a measure of vascular function. Following treatment with Irinophore C, 19F magnetic resonance spectroscopy was used to monitor the delivery of 5-fluorouracil (5-FU) to the tumor tissue, whereas scintigraphy was used to quantify the presence of bound [14C]5-FU.

RESULTS

Irinophore C decreased cell density (P = 8.42 x 10(-5)), the overall number of endothelial cells in the entire section (P = 0.014), tumor hypoxia (P = 5.32 x 10(-9)), and K(trans) (P = 0.050). However, treatment increased the ratio of endothelial cells to cell density (P = 0.00024) and the accumulation of Hoechst 33342 (P = 0.022), doxorubicin (P = 0.243 x 10(-5)), and 5-FU (P = 0.0002) in the tumor. Vascular endothelial growth factor and interleukin-8, two proangiogenic factors, were down-regulated, whereas the antiangiogenic factor TIMP-1 was up-regulated in Irinophore C-treated tumors.

CONCLUSIONS

Irinophore C treatment improves the vascular function of the tumor, thereby reducing tumor hypoxia and increasing the delivery and accumulation of a second drug. Reducing hypoxia would enhance radiotherapy, whereas improving delivery of a second drug to the tumor should result in higher cell kill.

Overexpression of OATP1B3 confers apoptotic resistance in colon cancer

Organic anion transporting polypeptide 1B3 (OATP1B3, SLCO1B3) is normally expressed in hepatocytes. In this study, we showed frequent overexpression of OATP1B3 in colorectal adenocarcinomas. Quantitative reverse transcription-PCR analysis of 17 colon tumors indicated tumoral overexpression of OATP1B3 by approximately 100-fold, compared with 20 normal colon samples (P < 0.0001). Using immunohistochemistry on a tissue microarray containing 93 evaluable colon tumor specimens, we detected immunostaining of OATP1B3 in 75 colon adenocarcinomas (81%) and no immunostaining in normal samples. To determine the functional effects of OATP1B3 expression on drug-induced apoptosis, we used camptothecin and oxaliplatin on a panel of colorectal cancer cell lines stably overexpressing OATP1B3. The results indicated that OATP1B3 overexpression enhanced cell survival in RKO, HCT-8, and HCT116(p53+/+) cells that harbor wild-type p53 but not in Caco-2 and HCT116(p53-/-) cells that lack p53, compared with the respective empty vector controls (P < 0.01). The terminal deoxynucleotidyl transferase-mediated nick-end labeling assay confirmed that HCT116(p53+/+) cells overexpressing OATP1B3 had significantly lower apoptotic levels compared with empty vector control (P < 0.001). The overexpression of OATP1B3 reduced the transcriptional activity of p53, with subsequent reductions in transcript and protein levels of its downstream transcription targets (P21WAF1 and PUMA). Overexpression of a point mutation (G583E) variant of OATP1B3 lacking transport activity did not confer an antiapoptotic effect or affect p53 transcriptional activity, suggesting that the antiapoptotic effect of OATP1B3 may be associated with its transport activity. Taken together, our results suggest that OATP1B3 overexpression in colorectal cancer cells may provide a survival advantage by altering p53-dependent pathways.

Organic anion transporting polypeptide 1B3 (OATP1B3) is overexpressed in colorectal tumors and is a predictor of clinical outcome

BACKGROUND AND AIMS

OATP1B3 is an organic anion transporting polypeptide (OATP) that functions as a multispecific transporter in the normal liver. We examined the expression and clinical significance of OATP1B3 in colon cancers in tissue microarrays.

METHODS

Immunohistochemistry was used to assess OATP1B3 protein expression in paraffinized colon tumor tissue microarrays. OATP1B3 immunostaining was evaluated by location and intensity. Relationships between OATP1B3 expression, known prognostic variables and clinical outcomes were examined.

RESULTS

278 colon tumor samples of all stages were evaluated for OATP1B3 expression. OATP1B3 immunostaining was detectable in the majority (56%) of the tumor samples. Higher OATP1B3 expression was seen in lower stage tumors (p = 0.003) and lower grade (p = 0.004) tumors, but was not predictive of 5-year survival or tumor recurrence as an independent variable. Within individual tumor grades, OATP1B3 expression was associated with improved 5-year survival, but not recurrence in patients with poorly differentiated tumors.

CONCLUSION

OATP1B3 expression was seen in the majority of colon tumors and may be a marker of lower grade and lower stage tumors and may predict for improved outcome in certain tumors.

Female fertility and colorectal cancer

PURPOSE

It is estimated that the incidence of cancer in women aged 40 years or less is 8%. Females under the age of 40 are in their childbearing years. In the Western world, colorectal cancer (CRC) is the most common malignancy of the gastrointestinal tract. It is the third most commonly diagnosed cancer and the second leading cause of cancer-related death in the USA. The incidence of CRC in patients under 40 is 3-6%. Over the past decades, there has been a significant improvement in survival rates due to progress in cancer treatment, including CRC. This has been achieved with advances in adjuvant chemotherapeutic regimens. In the case of locally advanced rectal cancer, radiation therapy is also used. Treatment for CRC may have adverse effects on female fertility. The purpose of this paper is to discuss the effects of treatment of CRC on female fertility as well as the options for fertility preservation.

MATERIALS AND METHODS

A review of relevant English language articles was performed on the basis of a MEDLINE search of the keywords: female, fertility, fecundity, colon, rectal cancer, fertility preservation, chemotherapy, and radiation.

RESULTS

Surgical resection for colon cancer possibly has no effect on female fertility. Resection below the peritoneal reflection may adversely affect fertility, based on lower fertility and fecundity rates associated with pelvic surgery for ulcerative colitis and familial adenomatous polyposis. Standard 5-FU-based chemotherapy may not have significant effects. The advent of oxaliplatin in adjuvant chemotherapy may be more harmful. Adjuvant and neoadjuvant radiation therapy may cause premature ovarian failure using current dosing schedules. The effect of pregnancy and female hormones on the incidence, progression, and recurrence of CRC remains unclear. Established methods for fertility preservation include ovarian transposition and embryo cryopreservation. Oocyte cryopreservation has yielded inferior results. An investigational fertility preservation method is ovarian tissue cryopreservation, with promising results. Ovarian suppression and the use of apoptotic inhibitors are also investigational at present.

CONCLUSION

Young female patients need to be informed about the effects of treatment on fertility and options for fertility preservation. A multidisciplinary approach for appropriate consultation of these patients is mandatory.

Contemporary Imaging for Colorectal Cancer

With improvements in therapy for colorectal cancer, accurate imaging has taken on an increased significance. Preoperative diagnosis of metastatic disease helps identify patients who could undergo combined resection or might benefit from systemic therapy before surgery. Accurate imaging of rectal cancer is critical in evaluating locally advanced disease treatable by combined modality therapy, including chemoradiation and surgery. Postoperative imaging enhances identification of recurrent disease that might be amenable to salvage surgery.