Comprehensive Analysis of miRNome Alterations in Response to Sorafenib Treatment in Colorectal Cancer Cells.

MicroRNAs (miRNAs) are master regulators of drug resistance and have been previously proposed as potential biomarkers for the prediction of therapeutic response in colorectal cancer (CRC). Sorafenib, a multi-kinase inhibitor which has been approved for the treatment of liver, renal and thyroid cancer, is currently being studied as a monotherapy in selected molecular subtypes or in combination with other drugs in metastatic CRC. In this study, we explored sorafenib-induced cellular effects in Kirsten rat sarcoma viral oncogene homolog olog (KRAS) wild-type and KRAS-mutated CRC cell lines (Caco-2 and HRT-18), and finally profiled expression changes of specific miRNAs within the miRNome (>1000 human miRNAs) after exposure to sorafenib. Overall, sorafenib induced a time- and dose-dependent growth-inhibitory effect through S-phase cell cycle arrest in KRAS wild-type and KRAS-mutated CRC cells. In HRT-18 cells, two human miRNAs (hsa-miR-597 and hsa-miR-720) and two small RNAs (SNORD 13 and hsa-miR-3182) were identified as specifically sorafenib-induced. In Caco-2 cells, nine human miRNAs (hsa-miR-3142, hsa-miR-20a, hsa-miR-4301, hsa-miR-1290, hsa-miR-4286, hsa-miR-3182, hsa-miR-3142, hsa-miR-1246 and hsa-miR-720) were identified to be differentially regulated post sorafenib treatment. In conclusion, we confirmed sorafenib as a potential anti-neoplastic treatment strategy for CRC cells by demonstrating a growth-inhibitory and cell cycle-arresting effect of this drug. Changes in the miRNome indicate that some specific miRNAs might be relevant as indicators for sorafenib response, drug resistance and potential targets for combinatorial miRNA-based drug strategies.

Genetic variants within obesity-related genes are associated with tumor recurrence in patients with stages II/III colon cancer.

OBJECTIVE: Obesity is an established risk factor for colorectal cancer (CRC) incidence and it is also linked to CRC recurrence and survival. Polymorphisms located in obesity-related genes are associated with an increased risk of developing several cancer types including CRC. We evaluated whether single-nucleotide polymorphisms in obesity-related genes may predict tumor recurrence in colon cancer patients. MATERIALS AND METHODS: Genotypes were obtained from germline DNA from 207 patients with stage II or III colon cancer at the Norris Comprehensive Cancer Center. Nine polymorphisms in eight obesity-related genes (PPAR, LEP, NFKB, CD36, DRG1, NGAL, REGIA, and DSCR1) were evaluated. The primary endpoint of the study was the 3-year recurrence rate. Positive associations were also tested in an independent Japanese cohort of 350 stage III CRC patients. RESULTS: In univariate analysis, for PPARrs1801282, patients with a CC genotype had significantly lower recurrence probability (29 ± 4% SE) compared with patients with a CG genotype (48 ± 8% SE) [hazard ratio (HR): 1.77; 95% confidence interval (CI), 1.01-3.10; P = 0.040]. For DSCR1rs6517239, patients with an AA genotype had higher recurrence probability than patients carrying at least one allele G (37 ± 4% SE vs. 15 ± 6% SE) (HR: 0.51; 95% CI, 0.27-0.94; P = 0.027). This association was stronger in the patients bearing a left-sided tumor (HR: 0.34; 95% CI, 0.13-0.88; P = 0.018). In the Japanese cohort, no associations were found. CONCLUSION: This hypothesis-generating study suggests a potential influence of polymorphisms within obesity-related genes in the recurrence probability of colon cancer. These interesting results should be evaluated further.

A functional germline variant in GLI1 implicates hedgehog signaling in clinical outcome of stage II and III colon carcinoma patients.

PURPOSE: Cumulating evidence indicates that germline variants in the Wnt, Notch, and Hedgehog pathways are involved in colon carcinoma progression and metastasis. We investigated germline polymorphisms in a comprehensive panel of Wnt, Notch, and Hedgehog pathway genes to predict time to recurrence (TTR) and overall survival in patients with stage II and III colon carcinoma. EXPERIMENTAL DESIGN: A total of 742 consecutively collected patients with stage II and III colon carcinoma were included in this retrospective study. Genomic DNA was analyzed for 18 germline polymorphisms in Wnt, Notch, and Hedgehog pathway genes (SFRP, DKK 2 and 3, AXIN2, APC, MYC, TCF7L2, NOTCH2, and GLI1) by TaqMan 5'-exonuclease assays. RESULTS: In univariate analysis, the homozygous mutant variant of GLI1 rs2228226 G>C was significantly associated with decreased TTR in a recessive genetic model after adjustment for multiple testing [HR = 2.35; confidence interval (95% CI), 1.48-3.74; P < 0.001] and remained significant in multivariate analysis including clinical stage, lymphovascular-, vascular-, and perineural-invasion (HR = 2.43; CI 95%, 1.52-3.87; P < 0.001). In subanalyses, the association was limited to patients with surgery alone (HR = 3.21; CI 95%, 1.59-6.49; P = 0.001), in contrast with patients with adjuvant chemotherapy (HR = 0.82; CI 95%, 0.35-1.95; P = 0.657). When the subgroup of patients with "high-risk" GLI1 rs2228226 C/C genotype was analyzed, no benefit of adjuvant 5-fluorouracil-based chemotherapy could be found. CONCLUSION: This is the first study identifying GLI1 rs2228226 G>C as an independent prognostic marker in patients with stage II and III colon carcinoma. Prospective studies are warranted to validate our findings.

Plastin polymorphisms predict gender- and stage-specific colon cancer recurrence after adjuvant chemotherapy.

Tumor recurrence after curative resection remains a major problem in patients with locally advanced colorectal cancer treated with adjuvant chemotherapy. Genetic single-nucleotide polymorphisms (SNP) may serve as useful molecular markers to predict clinical outcomes in these patients and identify targets for future drug development. Recent in vitro and in vivo studies have demonstrated that the plastin genes PLS3 and LCP1 are overexpressed in colon cancer cells and play an important role in tumor cell invasion, adhesion, and migration. Hence, we hypothesized that functional genetic variations of plastin may have direct effects on the progression and prognosis of locally advanced colorectal cancer. We tested whether functional tagging polymorphisms of PLS3 and LCP1 predict time to tumor recurrence (TTR) in 732 patients (training set, 234; validation set, 498) with stage II/III colorectal cancer. The PLS3 rs11342 and LCP1 rs4941543 polymorphisms were associated with a significantly increased risk for recurrence in the training set. PLS3 rs6643869 showed a consistent association with TTR in the training and validation set, when stratified by gender and tumor location. Female patients with the PLS3 rs6643869 AA genotype had the shortest median TTR compared with those with any G allele in the training set [1.7 vs. 9.4 years; HR, 2.84; 95% confidence interval (CI), 1.32-6.1; P = 0.005] and validation set (3.3 vs. 13.7 years; HR, 2.07; 95% CI, 1.09-3.91; P = 0.021). Our findings suggest that several SNPs of the PLS3 and LCP1 genes could serve as gender- and/or stage-specific molecular predictors of tumor recurrence in stage II/III patients with colorectal cancer as well as potential therapeutic targets.

Successful use of sorafenib after bortezomib failure in metastatic follicular thyroid cancer - a case report.

BACKGROUND: Thyroid cancer (TC) is the most commonly diagnosed endocrine malignancy in developed countries. Differentiated thyroid carcinoma (DTC), which includes papillary thyroid carcinoma and follicular thyroid carcinoma (FTC), composes more than 90% of all TC cases. When DTC recurs or metastasizes to distant sites despite the use of local and radiotherapeutic treatment modalities, the currently effective treatment options are limited. CASE REPORT: A then 40-year-old female Caucasian patient was diagnosed with FTC and underwent surgery and postoperative radioactive iodine therapy. The patient developed metastatic disease, and palliative first-line treatment with the proteasome inhibitor bortezomib was initiated. After 3 months, the patient suffered progressive pulmonary metastatic disease. Treatment with the multikinase inhibitor sorafenib was started, and after 3 months of therapy, tumor restaging demonstrated partial remission. The treatment is ongoing, and the current progression-free survival is 16 months. With the exception of mild diarrhea and hand-foot syndrome, the therapy was well tolerated, and no grade 3/4 adverse toxicities occurred. CONCLUSION: In our single case of metastatic FTC, sorafenib showed clinically meaningful antitumor activity accompanied by good tolerability. This case report supports the use of this drug as a potential treatment option for advanced/metastatic FTC.

Association of common gene variants in vitamin D modulating genes and colon cancer recurrence.

PURPOSE: Low concentrations of 25-hydroxyvitamin D3 (25(OH)D) have been associated with increased risk and poor prognosis of various cancer types, including colon cancer. Common genetic variants in genes that influence circulating 25(OH)D levels may affect vitamin D concentrations and risk of vitamin D insufficiency. In the present study, we investigated the association of three functional gene variants in GC (rs2282679 T>G), DHCR7 (rs12785878 G>T) and CYP2R1 (rs10741657 A>G) with time to recurrence (TTR) in patients with stages II and III colon cancer. METHODS: Two hundred and sixty-four patients were included in this retrospective study. Genomic DNA was genotyped for GC rs2282679 T>G, DHCR7 rs12785878 G>T and CYP2R1 rs10741657 A>G by 5'-exonuclease (TaqMan™) technology. RESULTS: In the univariate analysis, GC rs2282679 GG was significantly associated with decreased TTR (HR = 3.30, 95 % CI 1.09-9.97, p = 0.034) in patients with surgery alone and remained significantly associated in multivariate analysis including lymph node involvement and clinical stage (HR = 3.64, 95 % CI 1.16-11.46, p = 0.027). In patients with adjuvant chemotherapy, GC rs2282679 T>G was not significantly associated with TTR (HR = 1.02, 95 % CI 0.44-2.37, p = 0.964). Furthermore, we observed a trend toward decreased TTR in patients harboring the CYP2R1 rs10741657 A>G gene variant including all patients (HR = 1.50, 95 % CI 0.98-2.28, p = 0.060). No association was found between DHCR7 rs12785878 G>T and TTR in our study cohort. CONCLUSION: In conclusion, our results may indicate a prognostic effect of GC rs2282679 in stages II and III colon cancer patients with surgery alone. Larger studies have to be performed to validate our findings.

Single nucleotide polymorphisms of integrin alpha-2 and beta-3 genes are not associated with relapse-free and overall survival in colorectal cancer patients.

BACKGROUND: Integrins influence tumourigenesis, tumor progression and development of metastases. The impact of polymorphisms in integrin genes on relapse-free survival (RFS) and overall survival (OS) for 433 Caucasian patients with colorectal cancer was analysed in this retrospective study. PATIENTS AND METHODS: A Cox regression model including integrin genotype, age, grading, tumour size, number of lymph nodes examined, number of metastatic lymph nodes, stage and application of fluorouracil-based adjuvant chemotherapy was used to estimate their effect. RESULTS: After a median follow-up of 41 months for RFS and 55 months for OS, no significant correlation between the ITGA2 1648A allele (RFS p=0.618, OS p=0.604), the ITGA2 807T allele (RFS p=0.603, OS p=0.807) and the ITGB3 176C allele (RFS p=0.719, OS p=0.261) and survival was detectable. CONCLUSION: The investigated integrin polymorphisms are not associated with RFS or OS in colorectal cancer patients.