PI3-kinase/Wnt association mediates COX-2/PGE(2) pathway to inhibit apoptosis in early stages of colon carcinogenesis: chemoprevention by diclofenac

PI3K Pathway Alterations in Peritoneal Metastases are Associated with Earlier Recurrence in Patients with Colorectal Cancer Undergoing Optimal Cytoreductive Surgery

BACKGROUND

Colorectal cancer with peritoneal metastasis (CRC-PM) represents a biologically heterogeneous disease; yet little is known regarding the impact of tumor biology on survival outcomes following optimal cytoreductive surgery (CRS). We analyzed the frequency of alterations in cancer signaling pathways in patients with CRC-PM and their impact on recurrence-free survival (RFS) following optimal CRS.

METHODS

Thirty-five consecutive CRC-PM patients who underwent optimal CRS/HIPEC and next generation sequencing of peritoneal metastases were included in the study. Alterations in eight cancer-related signaling pathways were analyzed: Wnt/APC, p53, RTK-RAS, PI3K, TGF-B, Notch, Myc, and cell cycle. The association of pathway alterations with RFS and OS following optimal cytoreduction was estimated using Cox proportional hazard modeling.

RESULTS

The most frequently altered pathways were Wnt/APC (63%), p53 (63%), RTK-RAS (60%), and PI3K (23%). Among optimally cytoreduced patients with CRC-PM, PI3K pathway alterations were an independent predictor of worse RFS (hazard ratio 3.2, 95% confidence interval CI 1.3-8.3, p = 0.01) with a clinically meaningful impact on median months to recurrence (5 vs. 13 months, p = 0.02). Alterations in p53, Wnt, and RTK-RAS pathways were not significantly associated with a difference in RFS following CRS. Alterations in the four pathways were not associated with differences in OS following CRS (median OS was 50 (interquartile range 23-80) months).

CONCLUSIONS

In patients with CRC-PM, PI3K pathway alterations are associated with earlier recurrence following optimal CRS, which may represent a distinct molecular subtype. This novel finding can tailor clinical trials by using PIK3CA-directed interventions to reduce risk of recurrence after optimal CRS.

The PI3K/Akt/mTOR axis in colorectal cancer: Oncogenic alterations, non-coding RNAs, therapeutic opportunities, and the emerging role of nanoparticles

Colorectal cancer (CRC) is one of the deadliest human malignancies worldwide. Several molecular pathways have been demonstrated to be involved in the initiation and development of CRC which among them, the overactivation of the phosphatidyl-inositol 3-kinase (PI3K)/Akt/mTOR axis is of importance. The current review aims to unravel the mechanisms by which the PI3K/Akt/mTOR pathway affects CRC progression; and also, to summarize the original data obtained from international research laboratories on the oncogenic alterations and polymorphisms affecting this pathway in CRC. Besides, we provide a special focus on the regulatory role of noncoding RNAs targeting the PI3K/Akt/mTOR pathway in this malignancy. Questions on how this axis is involved in the inhibition of apoptosis, in the induction of drug resistance, and the angiogenesis, epithelial to mesenchymal transition, and metastasis are also responded. We also discussed the PI3K/Akt pathway-associated prognostic and predictive biomarkers in CRC. In addition, we provide a general overview of PI3K/Akt/mTOR pathway inhibition whether by chemical-based drugs or by natural-based medications in the context of CRC, either as monotherapy or in combination with other therapeutic agents; however, those treatments might have life-threatening side effects and toxicities. To the best of our knowledge, the current review is one of the first ones highlighting the emerging roles of nanotechnology to overcome challenges related to CRC therapy in the hope that providing a promising platform for the treatment of CRC.

Acetylsalicylic acid suppression of the PI3K pathway as a novel medical therapy for head and neck lymphatic malformations

OBJECTIVES

Head and neck lymphatic malformations (HNLM) are caused by gain-of-function somatic mutations in PIK3CA. Acetylsalicylic acid (ASA/aspirin) is thought to limit growth in PIK3CA-mutated neoplasms through PI3K pathway suppression. We sought to determine if ASA could be beneficial for HNLM.

METHODS

Retrospective case series of patients (0-18 years) offered ASA (3-5 mg/kg/day) for HNLM treatment (2010-2018). Clinical and treatment characteristics, patient-reported symptom improvement, medication tolerance, compliance, and complications were recorded. Treatment response was determined by change in patient/caregiver-reported symptoms, or HNLM size [complete (resolved), partial (decreased), or stable].

RESULTS

Fifty-three patients were offered ASA, 23 (43%) accepted (median age 10 years, IQR 6-14). Compared to patients who declined, patients receiving ASA were more likely to have extensive malformations: ex-utero intrapartum treatment procedure, bilateral malformations, oral cavity location, ≥2 invasive treatments, or tracheotomy (p < 0.05). All patients with tissue available had PIK3CA mutations (13/23). Treatment indications included oral pain/blebs (12, 52%), recurrent pain/swelling (6, 26%), or sudden/persistent swelling (5, 22%). Treatment plan was commonly one 81 mg tablet daily (19, 83%) for 3-12 months (8, 42%). Therapeutic adherence was reported by 18 patients (78%). Symptoms improved in 18 patients [78%; decreased pain (9, 39%) and swelling (8, 35%)]. Treatment resulted in partial (14, 61%) or complete response (4, 17%). Three patients developed oral bleb bleeding, which resolved with medication discontinuation.

CONCLUSION

ASA seems to be a well-tolerated, low-risk medication for HNLM treatment. This pilot study suggests that it often improves symptoms and reduces HNLM size. Further prospective, randomized studies are warranted to comprehensively assess indications, safety, and efficacy.

LEVEL OF EVIDENCE

Level 4.

Synthesis and Characterization of Some New Quinoxalin-2(1H)one and 2-Methyl-3H-quinazolin-4-one Derivatives Targeting the Onset and Progression of CRC with SRA, Molecular Docking, and ADMET Analyses

The pathogenesis of colorectal cancer is a multifactorial process. Dysbiosis and the overexpression of COX-2 and LDHA are important effectors in the initiation and development of the disease through chromosomal instability, PGE2 biosynthesis, and induction of the Warburg effect, respectively. Herein, we report the in vitro testing of some new quinoxalinone and quinazolinone Schiff’s bases as: antibacterial, COX-2 and LDHA inhibitors, and anticolorectal agents on HCT-116 and LoVo cells. Moreover, molecular docking and SAR analyses were performed to identify the structural features contributing to the biological activities. Among the synthesized molecules, the most active cytotoxic agent, (6d) was also a COX-2 inhibitor. In silico ADMET studies predicted that (6d) would have high Caco-2 permeability, and %HIA (99.58%), with low BBB permeability, zero hepatotoxicity, and zero risk of sudden cardiac arrest, or mutagenicity. Further, (6d) is not a potential P-gp substrate, instead, it is a possible P-gpI and II inhibitor, therefore, it can prevent or reverse the multidrug resistance of the anticancer drugs. Collectively, (6d) can be considered as a promising lead suitable for further optimization to develop anti-CRC agents or glycoproteins inhibitors.

Chrysin Suppresses HT-29 Cell Death Induced by Diclofenac through Apoptosis and Oxidative Damage

BACKGROUND

Diclofenac (Dic) was shown to increase in reactive oxygen species (ROS) levels thereby resulting oxidative stress and apoptotic cell death in colon cancer. The antioxidants can prevent and repair oxidative damage caused by ROS. The aim of this study was to assess the effect of chrysin (Chr) on Dic-induced toxicity in HT-29 and molecular mechanisms underlying its effect.

METHODS

Cell proliferation and cytotoxicity assays were carried out by WST-1 and LDH leakage assay, apoptotic index was calculated by TUNEL Assay, antioxidant parameters were studied by measurement of ROS, LPO and TAS levels and catalase activity, expression of caspase-3 protein levels were analyzed by immunohistochemical staining, mRNA levels of apoptotic and anti-apoptotic genes were studied by qRT-PCR.

RESULTS

The cellular processes of Dic-triggered cell death was associated with increase in ROS, malondialdehyde levels and lactate dehydrogenase release, decrease in total antioxidant and catalase activity while pretreatment with Chr reversed these effects. The expression level of p53, cas-3, cas-8, Bax and cytochrome c increased in Dic-exposed group while they were reduced by Chr.

CONCLUSION

The use of antioxidant nutritional supplements, and in particular of Chr, may reduce the efficacy of Dic in inducing apoptosis of colon cancer cells.

Probiotic Lactobacillus salivarius Ren prevent dimethylhydrazine-induced colorectal cancer through protein kinase B inhibition

Probiotics are known to be a potential agent for colorectal cancer (CRC) inhibition, but the precise mechanisms by which probiotic exert anti-tumorigenic effects remain to be explored. Lactobacillus salivarius (LS) Ren was isolated from centenarians living in Bama of China, which showed an anticancer potent in animal model of oral cancer. Here, we investigated the effect of LS on colorectal carcinogenesis and its putative mechanism. Oral administration of LS effectively suppressed the formation of dimethylhydrazine (DMH)-induced CRC in both initial and post-initial stages. Significant antiproliferation and proapoptotic effects were observed with inhibition of tumor formation by dietary intake of LS. Besides, LS metabolites inhibited growth, arrested cell cycle, and induced apoptosis of HT-29 cells. Furthermore, upon the treatment of LS, protein kinase B (AKT) phosphorylation and the downstream proteins of cyclinD1 and cyclooxygenase-2 (COX-2) were significantly downregulated in both in vivo and in vitro tests. These results showed that LS inhibited the colorectal carcinogenesis through suppressing AKT signaling pathway, resulting in suppressing cell proliferation and inducing cell apoptosis. Our findings suggest that this probiotic may act as a prophylactic agent for CRC prevention. Key points • LS effectively prevented rat colorectal carcinogenesis induced by DMH. • LS modulated the proliferation and apoptosis in both in vivo and in vitro. • LS inhibited AKT phosphorylation and expressions of downstream cyclinD1 and COX-2.

Relationship between aspirin use of esophageal, gastric and colorectal cancer patient survival: a meta-analysis

Background

Many studies have found that use of aspirin can lengthen survival in patients with gastrointestinal cancer. The aim of this study was to assess the survival benefit of aspirin use compared with non-aspirin use for patients with esophageal, gastric or colorectal cancer.

Methods

We searched online databases, including PubMed, the Cochrane Library, Embase and www.clinicaltrials.gov for studies that were conducted, before April 30th, 2020, to identify relevant studies. Overall survival and cancer-specific survival of esophageal, gastric and colorectal cancers among aspirin users were compared with those among non-aspirin users. Data extraction and quality evaluation were independently conducted by 2 investigators. A meta-analysis was performed to calculate the pooled risk ratios (RRs) for overall survival and cancer-specific survival by using either a fixed-effects model or a random-effects model.

Results

A total of 18 studies were included in this meta-analysis, with more than 74,936 patients. There were no significant differences between postdiagnosis aspirin use and overall survival for esophageal and gastric cancers. For colorectal cancer, a benefit that was associated with postdiagnosis aspirin use was observed for overall survival and cancer-specific survival [HR = 0.83, 95%CI(0.75, 0.9.);HR = 0.78, 95%CI(0.66, 0.92), respectively. However, a prediagnosis of aspirin use did not provide a benefit for overall or cancer-specific survival in colorectal cancer. HR values for overall and cancer-specific survival benefits for colorectal cancer associated with both prediagnosis and postdiagnosis aspirin were as follows: HR = 0.75, 95%CI(0.61, 0.92) and HR = 0.78, 95%CI(0.73, 0.85), respectively. In addition, the survival benefit of postdiagnosis aspirin use appeared to be confined to patients with mutated PIK3CA tumors [HR = 0.78, 95%CI(0.50, 0.99)] and was positive for PTGS2 (COX-2) expression [HR = 0.75, 95%CI(0.43, 1.30)].

Conclusions

These findings provide further indications that postdiagnosis aspirin use improves overall survival and cancer-specific survival in colorectal cancer, especially for patients who are positive for PTGS2 (COX-2) expression and PIK3CA-mutated tumors. However, aspirin therapy does not improve overall survival in esophageal and gastric cancers, although the meta-analysis was mainly limited to retrospective studies.

ASA Suppresses PGE2 in Plasma and Melanocytic Nevi of Human Subjects at Increased Risk for Melanoma

Potential anti-inflammatory and anticarcinogenic effects of aspirin (ASA) may be suitable for melanoma chemoprevention, but defining biomarkers in relevant target tissues is prerequisite to performing randomized controlled chemoprevention trials. We conducted open-label studies with ASA in 53 human subjects with melanocytic nevi at increased risk for melanoma. In a pilot study, 12 subjects received a single dose (325 mg) of ASA; metabolites salicylate, salicylurate, and gentisic acid were detected in plasma after 4–8 h, and prostaglandin E2 (PGE₂) was suppressed in both plasma and nevi for up to 24 h. Subsequently, 41 subjects received either 325 or 81 mg ASA (nonrandomized) daily for one week. ASA metabolites were consistently detected in plasma and nevi, and PGE₂ levels were significantly reduced in both plasma and nevi. Subchronic ASA dosing did not affect 5” adenosine monophosphate-activated protein kinase (AMPK) activation in nevi or leukocyte subsets in peripheral blood, although metabolomic and cytokine profiling of plasma revealed significant decreases in various (non-ASA-derived) metabolites and inflammatory cytokines. In summary, short courses of daily ASA reduce plasma and nevus PGE₂ and some metabolites and cytokines in plasma of human subjects at increased risk for melanoma. PGE₂ may be a useful biomarker in blood and nevi for prospective melanoma chemoprevention studies with ASA.

Exploring the Pharmacological Mechanism of the Herb Pair "HuangLian-GanJiang" against Colorectal Cancer Based on Network Pharmacology

Since the herb pair Huang Lian-Gan Jiang (HL-GJ) was put forward as conventional compatibility for cold-heat regulation in the middle energizer in the theory of Traditional Chinese Medicine (TCM), their therapeutic effects were observed on the prevention and treatment of intestinal inflammation and tumors including colorectal cancer (CRC). However, the active compounds, crucial targets, and related pathways of HL-GJ against CRC remained unclear. The purpose of this research was to establish a comprehensive and systemic approach that could identify the active compounds, excavate crucial targets, and reveal anti-CRC mechanisms of HL-GJ against CRC based on network pharmacology. We used methods including chemical compound screening based on absorption, distribution, metabolism, and excretion (ADME), compound target prediction, CRC target collection, network construction and analysis, Gene Ontology (GO), and pathway analysis. In this study, eight main active compounds of HL-GJ were identified, including Gingerenone C, Isogingerenone B, 5,8-dihydroxy-2-(2-phenylethyl) Chromone, 2,3,4-trihydroxy-benzenepropanoic acid, 3,4-dihydroxyphenylethyl Alcohol Glucoside, 3-carboxy-4-hydroxy-phenoxy Glucoside, Moupinamide, and Obaculactone. HRAS, KRAS, PIK3CA, PDE5A, PPARG, TGFBR1, and TGFBR2 were identified as crucial targets of HL-GJ against CRC. There were mainly 500 biological processes and 70 molecular functions regulated during HL-GJ against CRC (P < 0.001). There were mainly 162 signaling pathways contributing to therapeutic effects (P < 0.001), the top 10 of which included DAP12 signaling, signaling by PDGF, signaling by EGFR, NGF signaling via TRKA from the plasma membrane, signaling by NGF, downstream signal transduction, DAP12 interactions, signaling by VEGF, signaling by FGFR3, and signaling by FGFR4. The study established a comprehensive and systematic paradigm to understand the pharmacological mechanisms of multiherb compatibility such as an herb pair, which might accelerate the development and modernization of TCM.

Gene-environment interactions and colorectal cancer risk: An umbrella review of systematic reviews and meta-analyses of observational studies

The cause of colorectal cancer (CRC) is multifactorial, involving both genetic variants and environmental risk factors. We systematically searched the MEDLINE, EMBASE, China National Knowledge Infrastructure (CNKI) and Wanfang databases from inception to December 2016, to identify systematic reviews and meta-analyses of observational studies that investigated gene-environment (G×E) interactions in CRC risk. Then, we critically evaluated the cumulative evidence for the G×E interactions using an extension of the Human Genome Epidemiology Network's Venice criteria. Overall, 15 articles reporting systematic reviews of observational studies on 89 G×E interactions, 20 articles reporting meta-analyses of candidate gene- or single-nucleotide polymorphism-based studies on 521 G×E interactions, and 8 articles reporting 33 genome-wide G×E interaction analyses were identified. On the basis of prior and observed scores, only the interaction between rs6983267 (8q24) and aspirin use was found to have a moderate overall credibility score as well as main genetic and environmental effects. Though 5 other interactions were also found to have moderate evidence, these interaction effects were tenuous due to the lack of main genetic effects and/or environmental effects. We did not find highly convincing evidence for any interactions, but several associations were found to have moderate strength of evidence. Our conclusions are based on application of the Venice criteria which were designed to provide a conservative assessment of G×E interactions and thus do not include an evaluation of biological plausibility of an observed joint effect.

Effects of 5-FU and anti-EGFR antibody in combination with ASA on the spherical culture system of HCT116 and HT29 colorectal cancer cell lines

The aim of this study was to examine the effects of 5‑fluorouracil (5‑FU), anti‑epidermal growth factor receptor (EGFR) antibody and aspirin (ASA) on the characteristics of two CRC cell lines, HCT116 and HT29, maintained in a spherical culture system. We observed that the morphology of both the HCT116 and HT29 cell‑derived spheres was significantly impaired and the size of the colonospheres was markedly reduced following treatment with the aforementioned three drugs. In contrast to adherent cultures, the spherical cultures were more resistant to the tested drugs, as was reflected by their capacity to re‑create the colonospheres when sustained in serum‑free medium. Flow cytometric analysis of the drug‑treated HCT116 cell‑derived spheres revealed changes in the fraction of cells expressing markers of cancer stem cells (CSCs), whereas the CSC phenotype of HT29 cell‑derived colonospheres was affected to a lesser extent. All reagents enhanced the percentage of non‑viable cells in the colonospheres despite the diminished fraction of active caspase‑3‑positive cells following treatment of the HT29 cell‑derived spheres with anti‑EGFR antibody. Increased autophagy, assessed by acridine orange staining, was noted following the incubation of the HT29‑colonospheres with ASA and 5‑FU in comparison to the control. Notably, the percentage of cyclooxygenase (COX)‑2‑positive cells was not affected by ASA, although its activity was markedly elevated in the colonospheres incubated with anti‑EGFR antibody. On the whole, the findings of this study indicate that all the tested drugs were involved in different cellular processes, which suggests that they should be considered for the combined therapeutic treatment of CRC, particularly for targeting the population of CSC‑like cells. Thus, cancer cell‑derived spheres may be used as a preferable model for in vitro anticancer drug testing.

Expression profile and biological function of miR-455-5p in colorectal carcinoma

Underexpression of microRNA-455-5p (miR-455-5p) in medullary thyroid carcinoma, melanoma, gastric cancer and additional cancer types has been reported, which may be associated with carcinoma development. The present study aimed to evaluate the expression profile and biological role of miR-455-5p in colorectal carcinoma. Carcinoma tissues and adjacent tissue specimens from 40 patients with colorectal cancer were randomly collected. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis was conducted to detect the expression levels of miR-455-5p in colorectal carcinoma and adjacent normal tissues. The biological effects of miR-455-5p on selected colorectal cancer cells were assessed using bromodeoxyuridine assays, wound healing migration assays and flow cytometry. Bioinformatics analysis was implemented to predict the potential target genes of miR-455-5p in colorectal cancer. The expression levels of target genes were further validated by RT-qPCR and western blot analysis of the mRNA and protein levels. The results of the experiments demonstrated that miR-455-5p expression was downregulated in colorectal cancer tissues compared with adjacent normal tissues. In colorectal cancer cells (SW-480, HT-29 and HCT-116), miR-455-5p was observed to inhibit cell proliferation and migration while promoting cell apoptosis. Bioinformatics analysis predicted that the oncogene phosphoinositide-3-kinase regulatory subunit 1 (PIK3R1) was one of the top ranked target genes of miR-455-5p in colorectal cancer cells. This association was validated by RT-qPCR and western blotting. In vivo studies revealed that the expression level of miR-455-5p was significantly downregulated in human colorectal cancer. Further in vitro studies suggested that miR-455-5p may prevent the development of colorectal cancer by downregulating the oncogene PIK3R1. It was concluded that miR-455-5p may target and downregulate PIK3R1 in colorectal cancer.

Post-diagnosis aspirin use and survival in veterans with head and neck cancer

BACKGROUND

Our objective was to determine the effect of post-diagnosis aspirin use on survival in veterans with head and neck squamous cell carcinoma.

METHODS

Retrospective cohort study of 584 veterans with head and neck squamous cell carcinoma treated at the Washington DC VA Medical Center between 1995 and 2015. Charts were queried for clinical-pathologic data, aspirin prescriptions, and outcome. The Kaplan-Meier method was used to determine overall survival (OS) and disease-specific survival (DSS) among aspirin users and nonusers.

RESULTS

A total of 329 patients met inclusion criteria. Primary subsites included oropharynx (n = 143), larynx (n = 105), oral cavity (n = 62), and hypopharynx (n = 19). Eighty-four patients were aspirin users (25.5%). Aspirin users demonstrated significantly better 3-year OS and DSS (78.6% and 88.1%) compared to nonaspirin users (OS: 55.9% and DSS: 70.2%; P = .0003 and P = .0019, respectively). On multivariate analysis, aspirin use remained independently associated with improved survival.

CONCLUSION

Aspirin use following diagnosis and curative treatment of head and neck squamous cell carcinoma is associated with improved OS and DSS.

Aspirin acts in esophageal cancer: a brief review

Improved survival in esophageal cancer patients with regular aspirin use have been reported. However, with conflicting experimental results existed, an explicit definition on the role of aspirin as an adjuvant chemotherapy of esophageal cancer remains unestablished. We have summarized the current epidemiologic trials evidence over antitumor effect of aspirin in esophageal cancer in the past decades, and most of the clinical data supports that long-term regular aspirin use could reduce the mortality and improve the survival in patients with esophageal cancer. Although most of the clinical trials of aspirin on esophageal cancer are designed focusing on the prediagnosed chemo-preventive role, other than the post-diagnosed therapeutic role, it has been suggested by some studies that aspirin use as an adjuvant treatment after the standard surgery in esophageal cancer may benefit more. In the meanwhile, post diagnosed aspirin use may lead to lower risk of hemorrhage and other side effects of NSAIDs. Potential involved molecular pathways in the antitumor activities of aspirin are under studied worldwide for years and the possible mechanisms so far are reviewed in this article as cyclooxygenase (COX)-dependent pathways and COX-independent pathways, involving anti-inflammatory activity, apoptosis, platelet deactivation, PIK3CA mutation specificity and heparanase-related microenvironment changes of tumor cells. NOSH-aspirin has been developed as a succedaneum of aspirin with a wider application ranges by reducing the risk of hemorrhage in aspirin users. Further clinical and basic studies are suggested focusing on whether regular aspirin use as an adjuvant treatment prolongs survival and prevents recurrence in patients with esophageal cancer.

A Network Pharmacology Approach to Uncover the Multiple Mechanisms of Hedyotis diffusa Willd. on Colorectal Cancer

Background

As one of the most frequently diagnosed cancer diseases globally, colorectal cancer (CRC) remains an important cause of cancer-related death. Although the traditional Chinese herb Hedyotis diffusa Willd. (HDW) has been proven to be effective for treating CRC in clinical practice, its definite mechanisms have not been completely deciphered.

Objective

The aim of our research is to systematically explore the multiple mechanisms of HDW on CRC.

Methods

This study adopted the network pharmacology approach, which was mainly composed of active component gathering, target prediction, CRC gene collection, network analysis, and gene enrichment analysis.

Results

The network analysis showed that 10 targets might be the therapeutic targets of HDW on CRC, namely, HRAS, PIK3CA, KRAS, TP53, APC, BRAF, GSK3B, CDK2, AKT1, and RAF1. The gene enrichment analysis implied that HDW probably benefits patients with CRC by modulating pathways related to cancers, infectious diseases, endocrine system, immune system, nervous system, signal transduction, cellular community, and cell motility.

Conclusions

This study partially verified and predicted the pharmacological and molecular mechanism of HDW against CRC from a holistic perspective, which will also lay a foundation for the further experimental research and clinical rational application of HDW.

Mutations of KRAS, NRAS, BRAF, EGFR, and PIK3CA genes in urachal carcinoma: Occurence and prognostic significance

Purpose

Targeted therapy represents an attractive alternative for rare tumors such as urachal carcinoma (UrC). The aim of this study was to assess the mutations of the most commonly affected 5 genes in the targetable EGFR-pathway in UrC and comapre their frequencies to those of found in urothelial and colorectal cancer.

Materials and Methods

Mutational hot-spots of selected genes were tested in 22 UrC samples by pyrosequencing. Mutational patterns were compared to those published for colorectal and urothelial cancers. Furthermore, we sought correlations between mutations and clinicopathological and follow-up data.

Results

We found 11 mutations in 10 of 22 (45%) patients. The most frequently mutated gene was KRAS (27%) followed by BRAF (18%) and NRAS (5%), while no mutations were detected in the EGFR and PIK3CA genes. No correlation was found between the mutation status and clinicopathological parameters (Sheldon/Mayo stage, tumor grade, metastases). Furthermore, none of the mutations correlated with progression-free or overall survival.

Conclusions

The mutation pattern of UrC is more similar to colorectal than to urothelial cancer. However, the mutation characteristics of UrC seems to be unique suggesting that clinical decision-making for UrC cannot be simply adopted from urothelial or colorectal carcinoma. The high occurence of EGFR-pathway mutations warrants the testing for KRAS and BRAF mutations when considering anti-EGFR therapy in UrC.

The role of dietary polyphenols in the moderation of the inflammatory response in early stage colorectal cancer

Current focus in colorectal cancer (CRC) management is on reducing overall mortality by increasing the number of early-stage cancers diagnosed and treated with curative intent. Despite the success of screening programs in down-staging CRC, interval cancer rates are substantial and other strategies are desirable. Sporadic CRC is largely associated with lifestyle factors including diet. Polyphenols are phytochemicals ingested as part of a normal diet, which are abundant in plant foods including fruits/berries and vegetables. These may exert their anti-carcinogenic effects via the modulation of inflammatory pathways. Key signal transduction pathways are fundamental to the association of inflammation and disease progression including those mediated by NF-κB and STAT, PI3K and COX. Our aim was to examine the evidence for the effect of dietary polyphenols intake on tumor and host inflammatory responses to determine if polyphenols may be effective as part of a dietary intervention. There is good epidemiological evidence of a reduction in CRC risk from case-control and cohort studies assessing polyphenol intake. It would be premature to suggest a major public health intervention to promote their consumption; however, dietary change is safe and feasible, emphasizing the need for further investigation of polyphenols and CRC risk.

Genetic and epigenetic markers in colorectal cancer screening: recent advances

INTRODUCTION

Colorectal cancer (CRC) is a heterogenous disease which develops from benign intraepithelial lesions known as adenomas to malignant carcinomas. Acquired alterations in Wnt signaling, TGFβ, MAPK pathway genes and clonal propagation of altered cells are responsible for this transformation. Detection of adenomas or early stage cancer in asymptomatic patients and better prognostic and predictive markers is important for improving the clinical management of CRC. Area covered: In this review, the authors have evaluated the potential of genetic and epigenetic alterations as markers for early detection, prognosis and therapeutic predictive potential in the context of CRC. We have discussed molecular heterogeneity present in CRC and its correlation to prognosis and response to therapy. Expert commentary: Molecular marker based CRC screening methods still fail to gain trust of clinicians. Invasive screening methods, molecular heterogeneity, chemoresistance and low quality test samples are some key challenges which need to be addressed in the present context. New sequencing technologies and integrated omics data analysis of individual or population cohort results in GWAS. MPE studies following a GWAS could be future line of research to establish accurate correlations between CRC and its risk factors. This strategy would identify most reliable biomarkers for CRC screening and management.

Evaluation of PTGS2 Expression, PIK3CA Mutation, Aspirin Use and Colon Cancer Survival in a Population-Based Cohort Study

OBJECTIVES

The association between aspirin use and improved survival after colorectal cancer diagnosis may be more pronounced in tumors that have PIK3CA mutations or high PTGS2 expression. However, the evidence of a difference in association by biomarker status lacks consistency. In this population-based colon cancer cohort study the interaction between these biomarkers, aspirin use, and survival was assessed.

METHODS

The cohort consisted of 740 stage II and III colon cancer patients diagnosed between 2004 and 2008. Aspirin use was determined through clinical note review. Tissue blocks were retrieved to determine immunohistochemical assessment of PTGS2 expression and the presence of PIK3CA mutations. Cox proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI) for colorectal cancer-specific and overall survival.

RESULTS

In this cohort aspirin use was associated with a 31% improvement in cancer-specific survival compared to non-use (adjusted HR=0.69, 95% CI 0.47-0.98). This effect was more pronounced in tumors with high PTGS2 expression (PTGS2-high adjusted HR=0.55, 95% CI 0.32-0.96) compared to those with low PTGS2 expression (PTGS2-low adjusted HR=1.19, 95% CI 0.68-2.07, P for interaction=0.09). The aspirin by PTGS2 interaction was significant for overall survival (PTGS2-high adjusted HR=0.64, 95% CI 0.42-0.98 vs. PTGS2-low adjusted HR=1.28, 95% CI 0.80-2.03, P for interaction=0.04). However, no interaction was observed between aspirin use and PIK3CA mutation status for colorectal cancer-specific or overall survival.

CONCLUSIONS

Aspirin use was associated with improved survival outcomes in this population-based cohort of colon cancer patients. This association differed according to PTGS2 expression but not PIK3CA mutation status. Limiting adjuvant aspirin trials to PIK3CA-mutant colorectal cancer may be too restrictive.

Aspirin in pancreatic cancer: chemopreventive effects and therapeutic potentials

Pancreatic cancer is one of the most aggressive malignancies with dismal prognosis. Recently, aspirin has been found to be an effective chemopreventive agent for many solid tumors. However, the function of aspirin use in pancreatic cancer largely remains unknown. We herein argued that aspirin could also lower the risk of pancreatic cancer. Importantly, aspirin assumes pleiotropic effects by targeting multiple molecules. It could further target the unique tumor biology of pancreatic cancer and modify the cancer microenvironment, thus showing remarkable therapeutic potentials. Besides, aspirin could reverse the chemoradiation resistance by repressing tumor repopulation and exert synergistic potentials with metformin on pancreatic cancer chemoprevention. Moreover, aspirin secondarily benefits pancreatic cancer patients through modestly reducing cancer pain and the risk of venous thromboembolism. Furthermore, new aspirin derivatives and delivery systems might help to improve risk-to-benefit ratio. In brief, aspirin is a promising chemopreventive agent and exerts significant therapeutic potentials in pancreatic cancer.

A New Model to Study the Role of Arachidonic Acid in Colon Cancer Pathophysiology

A significant increase in cyclooxygenase 2 (COX2) gene expression has been shown to promote cylcooxygenase-dependent colon cancer development. Controversy associated with the role of COX2 inhibitors indicates that additional work is needed to elucidate the effects of arachidonic acid (AA)-derived (cyclooxygenase and lipoxygenase) eicosanoids in cancer initiation, progression, and metastasis. We have recently developed a novel Fads1 knockout mouse model that allows for the investigation of AA-dependent eicosanoid deficiency without the complication of essential fatty acid deficiency. Interestingly, the survival rate of Fads1-null mice is severely compromised after 2 months on a semi-purified AA-free diet, which precludes long-term chemoprevention studies. Therefore, in this study, dietary AA levels were titrated to determine the minimal level required for survival, while maintaining a distinct AA-deficient phenotype. Null mice supplemented with AA (0.1%, 0.4%, 0.6%, 2.0%, w/w) in the diet exhibited a dose-dependent increase (P < 0.05) in AA, PGE2, 6-keto PGF1α, TXB2, and EdU-positive proliferative cells in the colon. In subsequent experiments, null mice supplemented with 0.6% AA diet were injected with a colon-specific carcinogen (azoxymethane) in order to assess cancer susceptibility. Null mice exhibited significantly (P < 0.05) reduced levels/multiplicity of aberrant crypt foci (ACF) as compared with wild-type sibling littermate control mice. These data indicate that (i) basal/minimal dietary AA supplementation (0.6%) expands the utility of the Fads1-null mouse model for long-term cancer prevention studies and (ii) that AA content in the colonic epithelium modulates colon cancer risk. Cancer Prev Res; 9(9); 750-7. ©2016 AACR.

PIK3CA Mutation, Aspirin Use after Diagnosis and Survival of Colorectal Cancer. A Systematic Review and Meta-analysis of Epidemiological Studies

AIMS

Regular aspirin use has been associated with inhibition of the whole spectrum of colorectal carcinogenesis, including prevention of metastases and reduced total mortality in colorectal cancer. Preclinical data show that aspirin down-regulates PI3 kinase (PI3K) signalling activity through cyclo-oxygenase-2 (COX-2) inhibition, leading to the hypothesis that the effect of aspirin might be different according to PIK3CA mutational status, but epidemiological studies have led to conflicting results. The aim of this study was to assess the relationship between PIK3CA status and the efficacy of regular use of aspirin after diagnosis on overall survival in colorectal cancer patients.

MATERIALS AND METHODS

We identified studies that compared post-diagnosis aspirin efficacy in colorectal cancer patients identified by PIK3CA status. Hazard ratios for overall survival were meta-analysed according to PIK3CA status by inverse variance weighting. A pooled test for treatment by PIK3CA status interaction was carried out by weighted linear meta-regression. All statistical tests were two-sided.

RESULTS

The overall effect of aspirin was not significant (summary risk estimate = 0.82; 95% confidence interval 0.63-1.08, P = 0.16; I(2) = 57%). In PIK3CA mutant disease (n = 588), aspirin use reduced total mortality by 29% (summary risk estimate = 0.71; 95% confidence interval 0.51-0.99, P = 0.04; I(2) = 0%), whereas in PIK3CA wild-type disease (n = 4001), aspirin use did not reduce overall mortality (summary risk estimate = 0.93; 95% confidence interval 0.61-1.40; P = 0.7; I(2) = 80%) (P interaction = 0.39). There was a beneficial trend for aspirin on cancer-specific survival in PI3KCA mutated subjects (summary risk estimate = 0.37, 95% confidence interval 0.11-1.32, P = 0.1), albeit with high heterogeneity (Q chi-squared = 3.41, P = 0.07, I(2) = 70.7%).

CONCLUSION

These findings suggest that the benefit of post-diagnosis aspirin treatment on overall mortality in colorectal cancer may be more marked in PIK3CA mutated tumours, although the low number of studies prevents definitive conclusions. Trials addressing this issue are warranted to assess the efficacy of aspirin in the adjuvant setting.

A Randomized, Phase II Trial of Cetuximab With or Without PX-866, an Irreversible Oral Phosphatidylinositol 3-Kinase Inhibitor, in Patients With Metastatic Colorectal Carcinoma

BACKGROUND

The phosphotidylinositol-3 kinase (PI3K)/serine-threonine kinase/mammalian target of rapamycin signaling pathway is frequently altered in colorectal cancer (CRC). PX-866 is an oral, irreversible, pan-isoform inhibitor of PI3K. This randomized phase II study evaluated cetuximab with or without PX-866 in patients with metastatic, anti-epidermal growth factor receptor-naive, KRAS codon 12 and 13 wild-type CRC.

PATIENTS AND METHODS

Patients with metastatic CRC who had received both oxaliplatin and irinotecan were randomized (1:1) to cetuximab (400 mg/m² loading then 250 mg/m² weekly) with or without PX-866 (8 mg orally daily; arms A and B, respectively). The primary endpoint was progression-free survival (PFS). Secondary endpoints included objective response rate, overall survival (OS), toxicity, and correlation of relevant biomarkers with efficacy outcomes.

RESULTS

A total of 85 patients were enrolled. The median PFS was 59 days versus 104 days for arms A (cetuximab + PX-866) and B (cetuximab alone), respectively (P = .77). OS between the 2 arms (266 vs. 333 days for arm A vs. B) were similar (P = .83). Overall toxicity, including treatment-related toxicity, was higher in arm A compared with arm B, especially in terms of all-grade nausea (66% vs. 37%), vomiting (50% vs. 29%), diarrhea (64% vs. 18%), and rash (66% vs. 37%). Grade 3 diarrhea occurred in 19% of patients in Arm A and 0% in Arm B. PIK3CA mutations and PTEN loss by immunohistochemistry were infrequently seen.

CONCLUSION

The addition of PX-866 to cetuximab did not improve PFS, objective response rate, or OS in patients with metastatic CRC. The combination arm had greater toxicity and may have been harmful in this study.

Repositioning of drugs for intervention in tumor progression and metastasis: Old drugs for new targets

The increasing unraveling of the molecular basis of cancer offers manifold novel options for intervention strategies. However, the discovery and development of new drugs for potential clinical applications is a tremendously time-consuming and costly process. Translating a novel lead candidate compound into an approved clinical drug takes often more than a decade, and the success rate is very low due to versatile efforts including defining its pharmacokinetics, pharmacodynamics, side effects as well as lack of sufficient efficacy. Thus, strategies are needed to minimize time and costs, while maximizing success rates. A very attractive strategy for novel cancer therapeutic options is the repositioning of already approved drugs. These medicines, approved for the treatment of non-malignant disorders, have already passed some early costs and time, have been tested in humans and are ready for clinical trials as anti-cancer drugs. Here we discuss the repositioning of nonsteroidal anti-inflammatory drugs (NSAID), statins, anti-psychotic drugs, anti-helminthic drugs and vitamin D as anti-tumor agents. We focus on their novel actions and potential for inhibition of cancer growth and metastasis by interfering with target molecules and pathways, which drive these malignant processes. Furthermore, important pre-clinical and clinical data are reviewed herein, which elucidate their therapeutic mechanisms which enable their repositioning for cancer therapy and disruption of metastasis.

Repurposing Drugs in Oncology (ReDO)-diclofenac as an anti-cancer agent

Diclofenac (DCF) is a well-known and widely used non-steroidal anti-inflammatory drug (NSAID), with a range of actions which are of interest in an oncological context. While there has long been an interest in the use of NSAIDs in chemoprevention, there is now emerging evidence that such drugs may have activity in a treatment setting. DCF, which is a potent inhibitor of COX-2 and prostaglandin E2 synthesis, displays a range of effects on the immune system, the angiogenic cascade, chemo- and radio-sensitivity and tumour metabolism. Both pre-clinical and clinical evidence of these effects, in multiple cancer types, is assessed and summarised and relevant mechanisms of action outlined. Based on this evidence the case is made for further clinical investigation of the anticancer effects of DCF, particularly in combination with other agents - with a range of possible multi-drug and multi-modality combinations outlined in the supplementary materials accompanying the main paper.

Genetics and Genetic Biomarkers in Sporadic Colorectal Cancer

Sporadic colorectal cancer (CRC) is a somatic genetic disease in which pathogenesis is influenced by the local colonic environment and the patient's genetic background. Consolidating the knowledge of genetic and epigenetic events that occur with initiation, progression, and metastasis of sporadic CRC has identified some biomarkers that might be utilized to predict behavior and prognosis beyond staging, and inform treatment approaches. Modern next-generation sequencing of sporadic CRCs has confirmed prior identified genetic alterations and has classified new alterations. Each patient's CRC is genetically unique, propelled by 2-8 driver gene alterations that have accumulated within the CRC since initiation. Commonly observed alterations across sporadic CRCs have allowed classification into a (1) hypermutated group that includes defective DNA mismatch repair with microsatellite instability and POLE mutations in ∼15%, containing multiple frameshifted genes and BRAF(V600E); (2) nonhypermutated group with multiple somatic copy number alterations and aneuploidy in ∼85%, containing oncogenic activation of KRAS and PIK3CA and mutation and loss of heterozygosity of tumor suppressor genes, such as APC and TP53; (3) CpG island methylator phenotype CRCs in ∼20% that overlap greatly with microsatellite instability CRCs and some nonhypermutated CRCs; and (4) elevated microsatellite alterations at selected tetranucleotide repeats in ∼60% that associates with metastatic behavior in both hypermutated and nonhypermutated groups. Components from these classifications are now used as diagnostic, prognostic, and treatment biomarkers. Additional common biomarkers may come from genome-wide association studies and microRNAs among other sources, as well as from the unique alteration profile of an individual CRC to apply a precision medicine approach to care.

Aspirin use after diagnosis but not prediagnosis improves established colorectal cancer survival: a meta-analysis

OBJECTIVE

The objective of this meta-analysis was to systematically assess the survival benefit of aspirin use before or after diagnosis for patients with colorectal cancer (CRC).

DESIGN

Relevant studies were identified through searching PubMed, Embase and Cochrane databases before May 2014. Two investigators extracted data independently for baseline characteristics and outcomes from the included studies. Either a fixed-effects or a random-effects model was derived to composite the pooled HR for overall mortality and CRC-specific mortality of CRC.

RESULTS

Seven studies on postdiagnosis aspirin therapy and seven studies on prediagnosis aspirin use were finally included in this meta-analysis. The overall survival benefit associated with postdiagnosis aspirin use represented an HR of 0.84 (95% CI 0.75 to 0.94). This effect was observed both in colon cancer (HR=0.78, 95% CI 0.64 to 0.96) and in rectal cancer (HR=0.90, 95% CI 0.83 to 0.98). Besides, the survival benefit of postdiagnosis aspirin use appeared to be confined to those patients with positive prostaglandin endoperoxide synthase 2 (PTGS2, also known as cyclooxygenase-2, COX-2) expression (HR=0.65, 95% CI 0.50 to 0.85) and with mutated PIK3CA tumours (HR=0.58, 95% CI 0.37 to 0.90). Aspirin use postdiagnosis was not associated with CRC-specific mortality (HR=0.77, 95% CI 0.52 to 1.14). We observed no evidence of an association between prediagnosis aspirin use and CRC overall mortality (HR=1.01, 95% CI 0.96 to 1.06) or CRC-specific mortality (HR=0.93, 95% CI 0.82 to 1.05).

CONCLUSIONS

These findings provide further indication that postdiagnosis aspirin therapy improved CRC overall survival, especially for patients with positive PTGS2 (COX-2) expression and mutated PIK3CA tumours.

Association of aspirin and NSAID use with risk of colorectal cancer according to genetic variants

IMPORTANCE

Use of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with lower risk of colorectal cancer.

OBJECTIVE

To identify common genetic markers that may confer differential benefit from aspirin or NSAID chemoprevention, we tested gene × environment interactions between regular use of aspirin and/or NSAIDs and single-nucleotide polymorphisms (SNPs) in relation to risk of colorectal cancer.

DESIGN, SETTING, AND PARTICIPANTS

Case-control study using data from 5 case-control and 5 cohort studies initiated between 1976 and 2003 across the United States, Canada, Australia, and Germany and including colorectal cancer cases (n=8634) and matched controls (n=8553) ascertained between 1976 and 2011. Participants were all of European descent.

EXPOSURES

Genome-wide SNP data and information on regular use of aspirin and/or NSAIDs and other risk factors.

MAIN OUTCOMES AND MEASURES

Colorectal cancer.

RESULTS

Regular use of aspirin and/or NSAIDs was associated with lower risk of colorectal cancer (prevalence, 28% vs 38%; odds ratio [OR], 0.69 [95% CI, 0.64-0.74]; P = 6.2 × 10(-28)) compared with nonregular use. In the conventional logistic regression analysis, the SNP rs2965667 at chromosome 12p12.3 near the MGST1 gene showed a genome-wide significant interaction with aspirin and/or NSAID use (P = 4.6 × 10(-9) for interaction). Aspirin and/or NSAID use was associated with a lower risk of colorectal cancer among individuals with rs2965667-TT genotype (prevalence, 28% vs 38%; OR, 0.66 [95% CI, 0.61-0.70]; P = 7.7 × 10(-33)) but with a higher risk among those with rare (4%) TA or AA genotypes (prevalence, 35% vs 29%; OR, 1.89 [95% CI, 1.27-2.81]; P = .002). In case-only interaction analysis, the SNP rs16973225 at chromosome 15q25.2 near the IL16 gene showed a genome-wide significant interaction with use of aspirin and/or NSAIDs (P = 8.2 × 10(-9) for interaction). Regular use was associated with a lower risk of colorectal cancer among individuals with rs16973225-AA genotype (prevalence, 28% vs 38%; OR, 0.66 [95% CI, 0.62-0.71]; P = 1.9 × 10(-30)) but was not associated with risk of colorectal cancer among those with less common (9%) AC or CC genotypes (prevalence, 36% vs 39%; OR, 0.97 [95% CI, 0.78-1.20]; P = .76).

CONCLUSIONS AND RELEVANCE

In this genome-wide investigation of gene × environment interactions, use of aspirin and/or NSAIDs was associated with lower risk of colorectal cancer, and this association differed according to genetic variation at 2 SNPs at chromosomes 12 and 15. Validation of these findings in additional populations may facilitate targeted colorectal cancer prevention strategies.

The role of the PI3K pathway in colorectal cancer

In the last decade treatment for colorectal cancer (CRC) has evolved with the addition of contemporary chemotherapy drugs and targeted therapies. Despite this progress, our drug armamentarium is by no means complete and modern molecular biology techniques have led to the identification of a number of 'druggable' targets. One of the most important current drug targets is the phosphatidyl-inositol 3-kinase (PI3K) pathway, which is frequently deregulated in patients with CRC. In vitro and in vivo data strongly support the clinical development of compounds affecting signal transduction via the PI3K pathway. In this review we outline the role of PI3K in the development and progression of CRC and discuss data from current and ongoing clinical trials targeting this pathway. In addition we make suggestions toward the optimization of future research in order to derive the maximum benefit for patients with CRC.

Commonly used diabetes and cardiovascular medications and cancer recurrence and cancer-specific mortality: a review of the literature

INTRODUCTION

Cancer most commonly arises in the elderly who are often burdened with comorbidities. Medications used for treating these comorbidities may alter cancer prognosis. Understanding the impact of these medications on cancer is important in order to make effective evidence-based decisions about managing comorbidities while improving cancer outcomes.

AREAS COVERED

The evidence on diabetes, statins, antihypertensive and anti-inflammatory medications and their association with cancer recurrence and cancer-specific mortality are reviewed. The strengths and limitations of the existing literature, the current state of the field and future directions are discussed.

EXPERT OPINION

Metformin and aspirin were associated with a reduced risk of cancer recurrence and cancer-specific mortality. The evidence for statins and antihypertensive medications on cancer survival was inconsistent. There were few studies to suggest that any of the medication classes of interest were associated with negative effects on cancer survival. Methodological shortcomings within observational studies, such as confounding, distinguishing between use of medications pre-cancer versus post-cancer diagnosis/treatment, misclassification of exposures/outcomes, informative censoring and competing risks, must be considered. New observational studies addressing these limitations are essential. Some clinical trials are underway to further investigate the beneficial effects of these drugs and completed trials have confirmed results demonstrated in observational studies.

Discovery of colorectal cancer PIK3CA mutation as potential predictive biomarker: power and promise of molecular pathological epidemiology

Regular use of aspirin reduces incidence and mortality of various cancers, including colorectal cancer. Anticancer effect of aspirin represents one of the 'Provocative Questions' in cancer research. Experimental and clinical studies support a carcinogenic role for PTGS2 (cyclooxygenase-2), which is an important enzymatic mediator of inflammation, and a target of aspirin. Recent 'molecular pathological epidemiology' (MPE) research has shown that aspirin use is associated with better prognosis and clinical outcome in PIK3CA-mutated colorectal carcinoma, suggesting somatic PIK3CA mutation as a molecular biomarker that predicts response to aspirin therapy. The PI3K (phosphatidylinositol-4,5-bisphosphonate 3-kinase) enzyme has a pivotal role in the PI3K-AKT signaling pathway. Activating PIK3CA oncogene mutations are observed in various malignancies including breast cancer, ovarian cancer, brain tumor, hepatocellular carcinoma, lung cancer and colon cancer. The prevalence of PIK3CA mutations increases continuously from rectal to cecal cancers, supporting the 'colorectal continuum' paradigm, and an important interplay of gut microbiota and host immune/inflammatory reaction. MPE represents an interdisciplinary integrative science, conceptually defined as 'epidemiology of molecular heterogeneity of disease'. As exposome and interactome vary from person to person and influence disease process, each disease process is unique (the unique disease principle). Therefore, MPE concept and paradigm can extend to non-neoplastic diseases including diabetes mellitus, cardiovascular diseases, metabolic diseases, and so on. MPE research opportunities are currently limited by paucity of tumor molecular data in the existing large-scale population-based studies. However, genomic, epigenomic and molecular pathology testings (for example, analyses for microsatellite instability, MLH1 promoter CpG island methylation, and KRAS and BRAF mutations in colorectal tumors) are becoming routine clinical practices. In order for integrative molecular and population science to be routine practice, we must first reform education curricula by integrating both population and molecular biological sciences. As consequences, next-generation hybrid molecular biological and population scientists can advance science, moving closer to personalized precision medicine and health care.

Primary and acquired resistance to EGFR-targeted therapies in colorectal cancer: impact on future treatment strategies

Only approximately 10 % of genetically unselected patients with chemorefractory metastatic colorectal cancer experience tumor regression when treated with the anti-epidermal growth factor receptor (EGFR) antibodies cetuximab or panitumumab (“primary” or “de novo” resistance). Moreover, nearly all patients whose tumors initially respond inevitably become refractory (“secondary” or “acquired” resistance). An ever-increasing number of predictors of both primary and acquired resistance to anti-EGFR antibodies have been described, and it is now evident that most of the underlying mechanisms significantly overlap. By trying to extrapolate a unifying perspective out of many idiosyncratic details, here, we discuss the molecular underpinnings of therapeutic resistance, summarize research efforts aimed to improve patient selection, and present alternative therapeutic strategies that are now under development to increase response and combat relapse.

Molecular profiles of parvalbumin-immunoreactive neurons in the superior temporal cortex in schizophrenia

Dysregulation of pyramidal cell network function by the soma- and axon-targeting inhibitory neurons that contain the calcium-binding protein parvalbumin (PV) represents a core pathophysiological feature of schizophrenia. In order to gain insight into the molecular basis of their functional impairment, we used laser capture microdissection (LCM) to isolate PV-immunolabeled neurons from layer 3 of Brodmann's area 42 of the superior temporal gyrus (STG) from postmortem schizophrenia and normal control brains. We then extracted ribonucleic acid (RNA) from these neurons and determined their messenger RNA (mRNA) expression profile using the Affymetrix platform of microarray technology. Seven hundred thirty-nine mRNA transcripts were found to be differentially expressed in PV neurons in subjects with schizophrenia, including genes associated with WNT (wingless-type), NOTCH, and PGE2 (prostaglandin E2) signaling, in addition to genes that regulate cell cycle and apoptosis. Of these 739 genes, only 89 (12%) were also differentially expressed in pyramidal neurons, as described in the accompanying paper, suggesting that the molecular pathophysiology of schizophrenia appears to be predominantly neuronal type specific. In addition, we identified 15 microRNAs (miRNAs) that were differentially expressed in schizophrenia; enrichment analysis of the predicted targets of these miRNAs included the signaling pathways found by microarray to be dysregulated in schizophrenia. Taken together, findings of this study provide a neurobiological framework within which hypotheses of the molecular mechanisms that underlie the dysfunction of PV neurons in schizophrenia can be generated and experimentally explored and, as such, may ultimately inform the conceptualization of rational targeted molecular intervention for this debilitating disorder.

Recent advances in personalized colorectal cancer research

Colorectal cancer is one of the most prevalent cancers and a leading cause ofcancer-related death. It is also curable if detected early. The prognosis for metastatic colorectal cancer remains poor and resistance to chemotherapy is still a major obstacle in effective treatment. While many patients do not clinically benefit from chemotherapy, others experience adverse reactions resulting in dose modifications or treatment withdrawal, thereby reducing treatment efficacy. Researchefforts attempt to identify reliable biomarkers which will guide clinicians in decision making, while matching suitable therapeutic regimens. We here review currently known molecular biomarkers used for the personalized treatment of colorectal cancer.

Biomarkers in precision therapy in colorectal cancer

Colorectal cancer (CRC) is the most commonly diagnosed cancer in Europe. Because CRC is also a major cause of cancer-related deaths worldwide, a lot of research has been focused on the discovery and development of biomarkers to improve the diagnostic process and to predict treatment outcomes. Up till now only a few biomarkers are recommended by expert panels. Current TNM criteria, however, cause substantial under- and overtreatment of CRC patients. Consequently, there is a growing need for new and efficient biomarkers to ensure optimal treatment allocation. An ideal biomarker should be easily translated into clinical practice, to identify patients who can be spared from treatment or benefit from therapy, ultimately resulting in precision medicine in the future. In this review we aim to provide an overview of a number of frequently studied biomarkers in CRC and, at the same time, we will emphasize the challenges and controversies that withhold the clinical introduction of these biomarkers. We will discuss both prognostic and predictive markers of chemotherapy, aspirin therapy as well as overall therapy toxicity. Currently, only mutant KRAS, mutant BRAF, MSI and the Oncotype DX® Colon Cancer Assay are used in clinical practice. Other biomarker studies showed insufficient evidence to be introduced into clinical practice. Divergent patient selection criteria, absence of validation studies and a large number of single biomarker studies are possibly responsible. We therefore recommend that future studies focus on combining key markers, rather than analysing single markers, standardizing study protocols, and validate the results in independent study cohorts, followed by prospective clinical trials.

Dolastatin, along with Celecoxib, stimulates apoptosis by a mechanism involving oxidative stress, membrane potential change and PI3-K/AKT pathway down regulation

BACKGROUND

Phosphoinositide 3-kinase (PI3-K) is an important regulator of oncogenesis and apoptosis in various types of cancers including colon cancer. A combinatorial strategy of using Cyclooxygenase-2 inhibitor, Celecoxib and Dolastatin, a linear peptide from marine mollusks of Indian Ocean origin has shown anti-neoplastic effects in colon cancer in a rat model.

METHODS

The signal transduction pathway of PI3-K/AKT and the downstream signaling proteins had been studied in an early stage of colon carcinogenesis (DMH induced) by gene and protein expression, apoptotic studies by colonocyte apoptotic bleb assay, intracellular calcium level by fluorescence spectrometry, mitochondrial membrane potential by Rhodamine 123 flow cytometry and Reactive oxygen species measurement. Molecular docking analysis was employed to study the interaction of oncogenic proteins and the ligand, Celecoxib and Dolastatin.

RESULTS

Apoptotic cell index was lowered with DMH while both the drugs increased it and inhibited PI3-K and AKT expression. Docking studies revealed both the proteins targeted by the drugs via an ATP binding site. An increased expression of GSK-3β, pro-apoptotic protein Bad, transcription factor Egr-1, tumor suppressor protein PTEN while a downregulation of G1-associated cell cycle protein, Cyclin D1 and increased intracellular calcium as well as reactive oxygen species were observed. Also, the number of cells having a higher mitochondrial membrane potential was lowered.

CONCLUSION

Celecoxib and Dolastatin inhibited the tumor development through regulation of the PI3-K/AKT pathway which can act as a novel target for these drugs.

GENERAL SIGNIFICANCE

The anti-cancer properties of Dolastatin, a peptide isolated from marine mollusks in colorectal cancer is shown.

Aspirin use, tumor PIK3CA mutation, and colorectal-cancer survival

BACKGROUND

Regular use of aspirin after a diagnosis of colon cancer has been associated with a superior clinical outcome. Experimental evidence suggests that inhibition of prostaglandin-endoperoxide synthase 2 (PTGS2) (also known as cyclooxygenase-2) by aspirin down-regulates phosphatidylinositol 3-kinase (PI3K) signaling activity. We hypothesized that the effect of aspirin on survival and prognosis in patients with cancers characterized by mutated PIK3CA (the phosphatidylinositol-4,5-bisphosphonate 3-kinase, catalytic subunit alpha polypeptide gene) might differ from the effect among those with wild-type PIK3CA cancers.

METHODS

We obtained data on 964 patients with rectal or colon cancer from the Nurses' Health Study and the Health Professionals Follow-up Study, including data on aspirin use after diagnosis and the presence or absence of PIK3CA mutation. We used a Cox proportional-hazards model to compute the multivariate hazard ratio for death. We examined tumor markers, including PTGS2, phosphorylated AKT, KRAS, BRAF, microsatellite instability, CpG island methylator phenotype, and methylation of long interspersed nucleotide element 1.

RESULTS

Among patients with mutated-PIK3CA colorectal cancers, regular use of aspirin after diagnosis was associated with superior colorectal cancer-specific survival (multivariate hazard ratio for cancer-related death, 0.18; 95% confidence interval [CI], 0.06 to 0.61; P<0.001 by the log-rank test) and overall survival (multivariate hazard ratio for death from any cause, 0.54; 95% CI, 0.31 to 0.94; P=0.01 by the log-rank test). In contrast, among patients with wild-type PIK3CA, regular use of aspirin after diagnosis was not associated with colorectal cancer-specific survival (multivariate hazard ratio, 0.96; 95% CI, 0.69 to 1.32; P=0.76 by the log-rank test; P=0.009 for interaction between aspirin and PIK3CA variables) or overall survival (multivariate hazard ratio, 0.94; 95% CI, 0.75 to 1.17; P=0.96 by the log-rank test; P=0.07 for interaction).

CONCLUSIONS

Regular use of aspirin after diagnosis was associated with longer survival among patients with mutated-PIK3CA colorectal cancer, but not among patients with wild-type PIK3CA cancer. The findings from this molecular pathological epidemiology study suggest that the PIK3CA mutation in colorectal cancer may serve as a predictive molecular biomarker for adjuvant aspirin therapy. (Funded by The National Institutes of Health and others.).

Aspirin use, tumor PIK3CA mutation, and colorectal-cancer survival

BACKGROUND

Regular use of aspirin after a diagnosis of colon cancer has been associated with a superior clinical outcome. Experimental evidence suggests that inhibition of prostaglandin-endoperoxide synthase 2 (PTGS2) (also known as cyclooxygenase-2) by aspirin down-regulates phosphatidylinositol 3-kinase (PI3K) signaling activity. We hypothesized that the effect of aspirin on survival and prognosis in patients with cancers characterized by mutated PIK3CA (the phosphatidylinositol-4,5-bisphosphonate 3-kinase, catalytic subunit alpha polypeptide gene) might differ from the effect among those with wild-type PIK3CA cancers.

METHODS

We obtained data on 964 patients with rectal or colon cancer from the Nurses' Health Study and the Health Professionals Follow-up Study, including data on aspirin use after diagnosis and the presence or absence of PIK3CA mutation. We used a Cox proportional-hazards model to compute the multivariate hazard ratio for death. We examined tumor markers, including PTGS2, phosphorylated AKT, KRAS, BRAF, microsatellite instability, CpG island methylator phenotype, and methylation of long interspersed nucleotide element 1.

RESULTS

Among patients with mutated-PIK3CA colorectal cancers, regular use of aspirin after diagnosis was associated with superior colorectal cancer-specific survival (multivariate hazard ratio for cancer-related death, 0.18; 95% confidence interval [CI], 0.06 to 0.61; P<0.001 by the log-rank test) and overall survival (multivariate hazard ratio for death from any cause, 0.54; 95% CI, 0.31 to 0.94; P=0.01 by the log-rank test). In contrast, among patients with wild-type PIK3CA, regular use of aspirin after diagnosis was not associated with colorectal cancer-specific survival (multivariate hazard ratio, 0.96; 95% CI, 0.69 to 1.32; P=0.76 by the log-rank test; P=0.009 for interaction between aspirin and PIK3CA variables) or overall survival (multivariate hazard ratio, 0.94; 95% CI, 0.75 to 1.17; P=0.96 by the log-rank test; P=0.07 for interaction).

CONCLUSIONS

Regular use of aspirin after diagnosis was associated with longer survival among patients with mutated-PIK3CA colorectal cancer, but not among patients with wild-type PIK3CA cancer. The findings from this molecular pathological epidemiology study suggest that the PIK3CA mutation in colorectal cancer may serve as a predictive molecular biomarker for adjuvant aspirin therapy. (Funded by The National Institutes of Health and others.).

Expression of p27, COX-2, MLH1, and MSH2 in young patients with colon carcinoma and correlation with morphologic findings

Despite an overall decrease in colorectal carcinoma incidence, rates of colorectal carcinoma have increased substantially in patients aged less than 40 years. Several authors have characterized morphologic features of colorectal carcinoma in young patients, with variable results. To date, there has been 1 detailed molecular and immunohistochemical study in young patients with colorectal carcinoma. We sought to expand the data regarding young patients with colorectal carcinoma by a detailed assessment of morphologic features and by assaying expression of p27, COX-2, MLH1, and MSH2, markers with prognostic or therapeutic implications in colorectal carcinoma. We searched our pathology database from 1985 to 2009 and, after exclusion of cases with insufficient data or neoadjuvant therapy, identified a study population of 23 patients aged 40 or younger, 35 patients between 41 and 49 years of age, and a control group of 83 colorectal carcinoma patients aged 50 or older. Younger patients had higher tumor grade (P = .0085), with a trend toward mucinous differentiation and lymphovascular and perineural invasion. Loss of MSH2 was more prominent in younger patients (P = .02). Loss of p27 expression was not associated with age, but was associated with higher tumor stage (P = .0278), mucinous/signet ring differentiation (P = .0185), loss of either MLH1 or MSH2 (P = .0035), and larger tumor size (P = .0019). There was a trend toward lower COX-2 expression in younger patients, with less COX-2 expression relative to previously published data. Our findings support some prior reports regarding morphologic features in colorectal carcinoma in young patients and provide novel data on expression of several markers in this population.

Updates from the Intestinal Front Line: Autophagic Weapons against Inflammation and Cancer

The intestine lies at the interface between the organism and its environment and responds to infection/inflammation in a multi-leveled manner, potentially leading to chronic inflammatory pathologies and cancer formation. Indeed, the immune response at the intestinal epithelium has been found to be involved in the origin and development of colorectal cancer, which is the third most commonly diagnosed neoplastic disease. Among the mechanisms induced upon inflammation, autophagy appears as a defensive strategy for the clearance of invading microbes and intracellular waste components. Autophagy has also been found to play an important role in colorectal cancer, where it seems to have a pro-survival or pro-death function depending on the stage of the neoplastic process. In this paper we discuss the dual role of autophagy in colorectal cancer and review evidence showing that modulation of autophagy affects the immune response and cancer biology. The study of key players involved in autophagy might contribute to the design of new approaches for colorectal cancer, consisting in combined therapies capable of modifying cancer-specific metabolism rather than simply evoking a generic apoptotic and/or autophagic response, thus enhancing the efficacy of currently used drugs and treatments.

Up-regulation of p53 and mitochondrial signaling pathway in apoptosis by a combination of COX-2 inhibitor, Celecoxib and Dolastatin 15, a marine mollusk linear peptide in experimental colon carcinogenesis

Programmed cell death, also known as apoptosis, is an active process occurring in eukaryotic cells and it depends on various sets of pro and anti-apoptotic proteins. Chemoprevention of colorectal cancer can be achieved by inducing apoptosis using synthetic compound, Celecoxib and natural peptide, Dolastatin 15 in an effective manner. But the apoptotic signaling by these two drugs remain unclear. The present study was thus focused on the role of Bcl2 family of proteins and their interplay with p53 in rats during the chemoprevention by these two drugs. After treatment for 6 wk with 1, 2-dimethylhydrazine (DMH), animals showed a marked occurrence of multiple plaque lesions. However, a simultaneous treatment with Celecoxib and Dolastatin 15 decreases such number to a significant level. DMH treatment also decreases the number of apoptotic cells in the colonic enterocytes which were corrected to the normal level by Celecoxib and Dolastatin 15. An increased expression of Bcl2 while other proteins like Bax, Apaf-1, cyt c, and caspases in the apoptotic pathway, and the tumor suppressor proteins, p53 and p21 get down-regulated after DMH treatment which were reverted back to normal with Celecoxib and Dolastatin 15. Also, cells having high mitochondrial membrane potential had been seen to increase to significant levels which were reduced after the administration of these anti-inflammatory drugs. In silico molecular docking studies also showed that Dolastatin 15 and Celecoxib may bind to the active site pocket of Bcl2 , thus revealing the direct target of Dolastatin 15 and Celecoxib apart from binding to COX-2.