Chemotherapy combined with the angiogenesis inhibitor bevacizumab (BVZ) is approved as a first-line treatment in metastatic colorectal cancer (mCRC). Limited clinical benefit underpins the need for ...improved understanding of resistance mechanisms and the elucidation of novel predictive biomarkers. We assessed germline single-nucleotide polymorphisms (SNPs) in 180 mCRC patients (Angiopredict APD cohort) treated with combined BVZ + chemotherapy and investigated previously reported predictive SNPs. We further employed a machine learning approach to identify novel associations. In the APD cohort IL8 rs4073 any A carriers, compared to TT carriers, were associated with worse progression-free survival (PFS) (HR = 1.51, 95% CI:1.03-2.22, p-value = 0.037) and TBK1 rs7486100 TT carriers, compared to any A carriers, were associated with worse PFS in KRAS wild-type (wt) patients (HR = 1.94, 95% CI:1.04-3.61, p-value = 0.037), replicating previous findings. Machine learning identified novel associations in genes encoding the inflammasome protein NLRP1 and the ER protein Sarcalumenin (SRL). A negative association between PFS and carriers of any A at NLRP1 rs12150220 and AA for SRL rs13334970 in APD KRAS wild-type patients (HR = 4.44, 95% CI:1.23-16.13, p-value = 0.005), which validated in two independent clinical cohorts involving BVZ, MAVERICC and TRIBE. Our findings highlight a key role for inflammation and ER signalling underpinning BVZ + chemotherapy responsiveness.
We previously found that cellular FLICE-inhibitory protein (c-FLIP), caspase 8, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor 2 (DR5) are major regulators of cell ...viability and chemotherapy-induced apoptosis in colorectal cancer. In this study, we determined the prognostic significance of c-FLIP, caspase 8, TRAIL and DR5 expression in tissues from patients with stage II and III colorectal cancer.
Tissue microarrays were constructed from matched normal and tumor tissue derived from patients (n = 253) enrolled in a phase III trial of adjuvant 5-fluorouracil-based chemotherapy versus postoperative observation alone. TRAIL, DR5, caspase 8, and c-FLIP expression levels were determined by immunohistochemistry.
Colorectal tumors displayed significantly higher expression levels of c-FLIP (P < 0.001), caspase 8 (P = 0.01), and DR5 (P < 0.001), but lower levels of TRAIL (P < 0.001) compared with matched normal tissue. In univariate analysis, higher TRAIL expression in the tumor was associated with worse overall survival (P = 0.026), with a trend to decreased relapse-free survival (RFS; P = 0.06), and higher tumor c-FLIP expression was associated with a significantly decreased RFS (P = 0.015). Using multivariate predictive modeling for RFS in all patients and including all biomarkers, age, treatment, and stage, we found that the model was significant when the mean tumor c-FLIP expression score and disease stage were included (P < 0.001). As regards overall survival, the overall model was predictive when both TRAIL expression and disease stage were included (P < 0.001).
High c-FLIP and TRAIL expression may be independent adverse prognostic markers in stage II and III colorectal cancer and might identify patients most at risk of relapse.
Key to the clinical management of colorectal cancer is identifying tools which aid in assessing patient prognosis and determining more effective and personalised treatment strategies. We evaluated ...whether an experimental systems biology strategy which analyses the susceptibility of cancer cells to undergo caspase activation can be exploited to predict patient responses to 5-fluorouracil-based chemotherapy and to case-specifically identify potential alternative targeted treatments to reactivate apoptosis.
We quantified five essential apoptosis-regulating proteins (Pro-Caspases 3 and 9, APAF-1, SMAC and XIAP) in samples of Stage II (n = 13) and III (n=17) tumour and normal colonic (n = 8) tissue using absolute quantitative immunoblotting and employed systems simulations of apoptosis signalling to predict the susceptibility of tumour cells to execute apoptosis. Additional systems analyses assessed the efficacy of novel apoptosis-inducing therapeutics such as XIAP antagonists, proteasome inhibitors and Pro-Caspase-3-activating compounds in restoring apoptosis execution in apoptosis-incompetent tumours.
Comparisons of caspase activity profiles demonstrated that the likelihood of colorectal tumours to undergo apoptosis decreases with advancing disease stage. Systems-level analysis correctly predicted positive or negative outcome in 85% (p=0.004) of colorectal cancer patients receiving 5-fluorouracil based chemotherapy and significantly outperformed common uni- and multi-variate statistical approaches. Modelling of individual patient responses to novel apoptosis-inducing therapeutics revealed markedly different inter-individual responses.
Our study represents the first proof-of-concept example demonstrating the significant clinical potential of systems biology-based approaches for predicting patient outcome and responsiveness to novel targeted treatment paradigms.
Apoptosis is essential for chemotherapy responses. In this discovery and validation study, we evaluated the suitability of a mathematical model of apoptosis execution (APOPTO-CELL) as a stand-alone ...signature and as a constituent of further refined prognostic stratification tools.
Apoptosis competency of primary tumor samples from patients with stage III colorectal cancer (
= 120) was calculated by APOPTO-CELL from measured protein concentrations of Procaspase-3, Procaspase-9, SMAC, and XIAP. An enriched APOPTO-CELL signature (APOPTO-CELL-PC3) was synthesized to capture apoptosome-independent effects of Caspase-3. Furthermore, a machine learning Random Forest approach was applied to APOPTO-CELL-PC3 and available molecular and clinicopathologic data to identify a further enhanced signature. Association of the signature with prognosis was evaluated in an independent colon adenocarcinoma cohort (TCGA COAD,
= 136).
We identified 3 prognostic biomarkers (
= 0.04,
= 0.006, and
= 0.0004 for APOPTO-CELL, APOPTO-CELL-PC3, and Random Forest signatures, respectively) with increasing stratification accuracy for patients with stage III colorectal cancer.The APOPTO-CELL-PC3 signature ranked highest among all features. The prognostic value of the signatures was independently validated in stage III TCGA COAD patients (
= 0.01,
= 0.04, and
= 0.02 for APOPTO-CELL, APOPTO-CELL-PC3, and Random Forest signatures, respectively). The signatures provided further stratification for patients with CMS1-3 molecular subtype.
The integration of a systems-biology-based biomarker for apoptosis competency with machine learning approaches is an appealing and innovative strategy toward refined patient stratification. The prognostic value of apoptosis competency is independent of other available clinicopathologic and molecular factors, with tangible potential of being introduced in the clinical management of patients with stage III colorectal cancer.
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Prostaglandin E2 (PGE2) is the major product of Cyclooxygenase-2 (COX-2) in colorectal cancer (CRC). We aimed to assess PGE2 cell surface receptors (EP 1-4) to examine the mechanisms by which PGE2 ...regulates tumour progression.
Gene expression studies were performed by quantitative RT-PCR. Cell cycle was analysed by flow cytometry with cell proliferation quantified by BrdU incorporation measured by enzyme immunoassay. Immunohistochemistry was employed for expression studies on formalin fixed paraffin embedded tumour tissue.
EP4 was the most abundant subtype of PGE2 receptor in HT-29 and HCA7 cells (which show COX-2 dependent PGE2 generation) and was consistently the most abundant transcript in human colorectal tumours (n = 8) by qRT-PCR (ANOVA, p = 0.01). G0/G1 cell cycle arrest was observed in HT-29 cells treated with SC-236 5 microM (selective COX-2 inhibitor) for 24 hours (p = 0.02), an effect abrogated by co-incubation with PGE2 (1 microM). G0/G1 arrest was also seen with a specific EP4 receptor antagonist (EP4A, L-161982) (p = 0.01). Treatment of HT-29 cells with either SC-236 or EP4A caused reduction in intracellular cAMP (ANOVA, p = 0.01). Early induction in p21WAF1/CIP1 expression (by qRT-PCR) was seen with EP4A treatment (mean fold increase 4.4, p = 0.04) while other genes remained unchanged. Similar induction in p21WAF1/CIP1 was also seen with PD153025 (1 microM), an EGFR tyrosine kinase inhibitor, suggesting EGFR transactivation by EP4 as a potential mechanism. Additive inhibition of HCA7 proliferation was observed with the combination of SC-236 and neutralising antibody to amphiregulin (AR), a soluble EGFR ligand. Concordance in COX-2 and AR localisation in human colorectal tumours was noted.
COX-2 regulates cell cycle transition via EP4 receptor and altered p21WAF1/CIP1 expression. EGFR pathways appear important. Specific targeting of the EP4 receptor or downstream targets may offer a safer alternative to COX-2 inhibition in the chemoprevention of CRC.
Triple-negative breast cancer (TNBC), is a heterogeneous disease characterised by absence of expression of the estrogen receptor (ER), progesterone receptor (PR) and lack of amplification of human ...epidermal growth factor receptor 2 (HER2). TNBC patients can exhibit poor prognosis and high recurrence stages despite early response to chemotherapy treatment. In this study, we identified a pro-survival signalling protein BCL2- associated athanogene 3 (BAG3) to be highly expressed in a subset of TNBC cell lines and tumour tissues. High mRNA expression of BAG3 in TNBC patient cohorts significantly associated with a lower recurrence free survival. The epidermal growth factor receptor (EGFR) is amplified in TNBC and EGFR signalling dynamics impinge on cancer cell survival and disease recurrence. We found a correlation between BAG3 and EGFR expression in TNBC cell lines and determined that BAG3 can regulate tumour cell proliferation, migration and invasion in EGFR expressing TNBC cells lines. We identified an interaction between BAG3 and components of the EGFR signalling networks using mass spectrometry. Furthermore, BAG3 contributed to regulation of proliferation in TNBC cell lines by reducing the activation of components of the PI3K/AKT and FAK/Src signalling subnetworks. Finally, we found that combined targeting of BAG3 and EGFR was more effective than inhibition of EGFR with Cetuximab alone in TNBC cell lines. This study demonstrates a role for BAG3 in regulation of distinct EGFR modules and highlights the potential of BAG3 as a therapeutic target in TNBC.
Deregulation of the ubiquitin-proteasome pathway has been frequently observed in a number of malignancies. Using quantitative Western blotting of normal and matched tumour tissue, we here identified ...a significant increase in the 19S proteasome subunit Rpt4 in response to chemoradiation in locally advanced rectal cancer patients with unfavourable outcome. We therefore explored the potential of Rpt4 reduction as a therapeutic strategy in colorectal cancer (CRC). Utilizing siRNA to down regulate Rpt4 expression, we show that silencing of Rpt4 reduced proteasomal activity and induced endoplasmic reticulum stress. Gene silencing of Rpt4 also inhibited cell proliferation, reduced clonogenic survival and induced apoptosis in HCT-116 colon cancer cells. We next developed a cell penetrating peptide-based nanoparticle delivery system to achieve in vivo gene silencing of Rpt4. Administration of Rpt4 siRNA nanoparticles reduced tumour growth and improved survival in a HCT-116 colon cancer xenograft tumour model in vivo. Collectively, our data suggest that inhibition of Rpt4 represents a novel strategy for the treatment of CRC.
The prostanoid thromboxane (TX)A2 plays a central role in haemostasis and is increasingly implicated in cancer progression. TXA2 signals through two T Prostanoid receptor (TP) isoforms termed TPα and ...TPβ, with both encoded by the TBXA2R gene. Despite exhibiting several functional and regulatory differences, the role of the individual TP isoforms in neoplastic diseases is largely unknown.This study evaluated expression of the TPα and TPβ isoforms in tumour microarrays of the benign prostate and different pathological (Gleason) grades of prostate cancer (PCa). Expression of TPβ was significantly increased in PCa relative to benign tissue and strongly correlated with increasing Gleason grade. Furthermore, higher TPβ expression was associated with increased risk of biochemical recurrence (BCR) and significantly shorter disease-free survival time in patients post-surgery. While TPα was more variably expressed than TPβ in PCa, increased/high TPα expression within the tumour also trended toward increased BCR and shorter disease-free survival time. Comparative genomic CpG DNA methylation analysis revealed substantial differences in the extent of methylation of the promoter regions of the TBXA2R that specifically regulate expression of TPα and TPβ, respectively, both in benign prostate and in clinically-derived tissue representative of precursor lesions and progressive stages of PCa. Collectively, TPα and TPβ expression is differentially regulated both in the benign and tumourigenic prostate, and coincides with clinical pathology and altered CpG methylation of the TBXA2R gene. Analysis of TPβ, or a combination of TPα/TPβ, expression levels may have significant clinical potential as a diagnostic biomarker and predictor of PCa disease recurrence.
Esophageal adenocarcinoma has the fastest growing incidence of any solid tumor in the Western world. Prognosis remains poor with overall five-year survival rates under 25 %. Only a limited number of ...patients benefit from chemotherapy and there are no biomarkers that can predict outcome. Previous studies have indicated that induction of autophagy can influence various aspects of tumor cell biology, including chemosensitivity. The objective of this study was to assess whether expression of the autophagy marker (LC3B) correlated with patient outcome.
Esophageal adenocarcinoma tumor tissue from two independent sites, was examined retrospectively. Tumors from 104 neoadjuvant naïve patients and 48 patients post neoadjuvant therapy were assembled into tissue microarrays prior to immunohistochemical analysis. Kaplan-Meier survival curves and log-rank tests were used to assess impact of LC3B expression on survival. Cox regression was used to examine association with clinical risk factors.
A distinct globular pattern of LC3B expression was found to be predictive of outcome in both patient groups, irrespective of treatment (p < 0.001). Multivariate analysis found that this was a strong independent predictor of poor prognosis (p < 0.001).
This distinctive staining pattern of LC3B represents a novel prognostic marker for resectable esophageal adenocarcinoma.
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