Albert Abad

Weekly regimen of irinotecan/docetaxel in previously treated non-small cell lung cancer patients and correlation with uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) polymorphism.

Purpose: Inherited variations in drug metabolizing enzymes may influence drug efficacy. This phase II study assesses the impact of second-line weekly irinotecan (CPT-11)/docetaxel in non-small cell lung cancer (NSCLC) patients, and gauges the uridine diphosphate glucuronosyl transferase (UGT1A1) polymorphism influence in toxicity and antitumor activity. Experimental Design: Fifty-one patients with NSCLC treated with at least one prior chemotherapy regimen were enrolled. Patients received irinotecan 70 mg/m2 followed by docetaxel 25 mg/m2. Both drugs were given on days 1, 8, and 15 every 28 days. UGT1A1 polymorphism were analyzed in blood samples of 47 patients. The UGT1A1 polymorphism are classified according to the number of TA repeats in the promoter region of this gene. Results: Three patients (6%) achieved a partial response and nineteen patients (37%) had stable disease. Median survival was 8 months (95% CI: 4.8–11.2) and 1-year survival 30%. Grade 3–4 hematologic toxicity was low (less than 10% of patients); 15% of patients had grade 3 asthenia and 25% of patients had grade 3/4 diarrhea. The frequency of UGT1A1 genotypes was as follows: 6/6 49%, 6/7 36%, and 7/7 15%. No differences in toxicity were observed according to UGT1A1 polymorphism. A nonsignificant improvement in time to progression (4 vs. 3 months) and median survival (11 vs. 8 months) was detected in patients with the variant alleles (6/7 and 7/7). Conclusions: This weekly irinotecan/docetaxel regimen has shown an acceptable toxicity profile while encouraging median and 1-year survival in heavily pretreated NSCLC patients. The tendency to better prognosis in patients carrying the variant genotypes 6/7 and 7/7 of UGT1A1 gene requires further validation.

Epigenetic Inactivation of the BRCA1 Interactor SRBC and Resistance to Oxaliplatin in Colorectal Cancer

Background A major problem in cancer chemotherapy is the existence of primary resistance and/or the acquisition of secondary resistance. Many cellular defects contribute to chemoresistance, but epigenetic changes can also be a cause. Methods A DNA methylation microarray was used to identify epigenetic differences in oxaliplatin-sensitive and -resistant colorectal cancer cells. The candidate gene SRBC was validated by single-locus DNA methylation and expression techniques. Transfection and short hairpin experiments were used to assess oxaliplatin sensitivity. Progression-free survival (PFS) and overall survival (OS) in metastasic colorectal cancer patients were explored with Kaplan–Meier and Cox regression analyses. All statistical tests were two-sided. Results We found that oxaliplatin resistance in colorectal cancer cells depends on the DNA methylation–associated inactivation of the BRCA1 interactor SRBC gene. SRBC overexpression or depletion gives rise to sensitivity or resistance to oxaliplatin, respectively. SRBC epigenetic inactivation occurred in primary tumors from a discovery cohort of colorectal cancer patients (29.8%; n = 39 of 131), where it predicted shorter PFS (hazard ratio [HR] = 1.83; 95% confidence interval [CI] = 1.15 to 2.92; log-rank P = .01), particularly in oxaliplatin-treated case subjects for which metastasis surgery was not indicated (HR = 1.96; 95% CI = 1.13 to 3.40; log-rank P = .01). In a validation cohort of unresectable colorectal tumors treated with oxaliplatin (n = 58), SRBC hypermethylation was also associated with shorter PFS (HR = 1.90; 95% CI = 1.01 to 3.60; log-rank P = .045). Conclusions These results provide a basis for future clinical studies to validate SRBC hypermethylation as a predictive marker for oxaliplatin resistance in colorectal cancer.

Circulating Tumor Cell Count Is a Prognostic Factor in Metastatic Colorectal Cancer Patients Receiving First-Line Chemotherapy Plus Bevacizumab: A Spanish Cooperative Group for the Treatment of Digestive Tumors Study

BACKGROUND The Maintenance in Colorectal Cancer trial was a phase III study to assess maintenance therapy with single-agent bevacizumab versus bevacizumab plus chemotherapy in patients with metastatic colorectal cancer. An ancillary study was conducted to evaluate the circulating tumor cell (CTC) count as a prognostic and/or predictive marker for efficacy endpoints. PATIENTS AND METHODS One hundred eighty patients were included. Blood samples were obtained at baseline and after three cycles. CTC enumeration was carried out using the CellSearch® System (Veridex LLC, Raritan, NJ). Computed tomography scans were performed at cycle 3 and 6 and every 12 weeks thereafter for tumor response assessment. RESULTS The median progression-free survival (PFS) interval for patients with a CTC count ≥3 at baseline was 7.8 months, versus the 12.0 months achieved by patients with a CTC count <3 (p = .0002). The median overall survival (OS) time was 17.7 months for patients with a CTC count ≥3, compared with 25.1 months for patients with a lower count (p = .0059). After three cycles, the median PFS interval for patients with a low CTC count was 10.8 months, significantly longer than the 7.5 months for patients with a high CTC count (p = .005). The median OS time for patients with a CTC count <3 was significantly longer than for patients with a CTC count ≥3, 25.1 months versus 16.2 months, respectively (p = .0095). CONCLUSIONS The CTC count is a strong prognostic factor for PFS and OS outcomes in metastatic colorectal cancer patients.

Pharmacogenomic approach for the identification of novel determinants of acquired resistance to oxaliplatin in colorectal cancer

Oxaliplatin is a third-generation platinum agent used in colorectal cancer treatment. Oxaliplatin resistance acquisition is a complex process mainly based on alteration of genes and pathways involved in its mechanism of action. Therefore, our purpose was to perform a gene expression screening in an in vitro model to identify genes that could play a role in oxaliplatin resistance acquisition processes. Four colorectal cancer cell lines and their oxaliplatin-resistant derived sublines were compared. Microarray analysis was done using Human 19K Oligo Array Slides. RNA from cells were hybridized with a commercial RNA reference sample and labeled with both fluorochromes Cy3 and Cy5. Data were analyzed by hierarchical clustering method. Subsequently, quantitative real-time PCR (qRT-PCR) was used to corroborate microarray data, considering as positively validated those genes that showed significant differences in expression levels between groups and a correlation between microarray and qRT-PCR data. By microarray analysis, 32 candidate genes were identified. After validation process by qRT-PCR, the genes AKT1, CDK5, TRIP, GARP, RGS11, and UGCGL1 were positively validated. The 3 first genes proved to be involved in regulation of nuclear factor-κβ antiapoptotic transcription factor previously related to drug resistance, and the other 3 genes are novel finds. We have identified 6 genes related to oxaliplatin resistance acquisition. These findings are of paramount importance to understand these processes better and open new lines of study to elucidate the relevance of this pharmacogenomic approach into the clinic. [Mol Cancer Ther 2009;8(1):194–202]

A proteomic approach links decreased pyruvate kinase M2 expression to oxaliplatin resistance in patients with colorectal cancer and in human cell lines

We aimed to gain further understanding of the molecular mechanisms involved in oxaliplatin resistance in colorectal cancer by using a proteomic approach. A 5-fold oxaliplatin-resistant cell line, HTOXAR3, was compared with its parental cell line, HT29, using two-dimensional PAGE. Mass spectrometry, Western blot, and real-time quantitative PCR confirmed the down-regulation of pyruvate kinase M2 (PK-M2) in HTOXAR3 cells. In a panel of eight colorectal cancer cell lines, we found a negative correlation between oxaliplatin resistance and PK-M2 mRNA levels (Spearman r = −0.846, P = 0.008). Oxaliplatin exposure in both HT29 and HTOXAR3 led to PK-M2 mRNA up-regulation. PK-M2 mRNA levels were measured by real-time quantitative PCR in 41 tumors treated with oxaliplatin/5-fluorouracil. Tumors with the lowest PK-M2 levels attained the lowest response rates (20% versus 64.5%, P = 0.026). High PK-M2 levels were associated with high p53 levels (P = 0.032). In conclusion, the data provided clearly link PK-M2 expression and oxaliplatin resistance mechanisms and further implicate PK-M2 as a predictive marker of response in patients with oxaliplatin-treated colorectal cancer.[Mol Cancer Ther 2009;8(4):771–8]

Elderly patients with advanced colorectal cancer derive similar benefit without excessive toxicity after first-line chemotherapy with oxaliplatin-based combinations: Comparative outcomes from the 03-TTD-01 phase III study

PURPOSE Healthy elderly patients with metastatic colorectal cancer may benefit from chemotherapy as much as the younger population. This analysis compares the outcomes of first-line oxaliplatin plus fluoropyrimidines in elderly versus young patients. PATIENTS AND METHODS 348 patients were randomized to capecitabine 1000 mg/(m2 12 h), days 1-14 plus oxaliplatin 130 mg/m2 day 1, every 3 weeks or weekly infusional 5-FU 2250 mg/m2 over 48 h plus bimonthly oxaliplatin 85 mg/m2. We evaluated response rate, time to progression, overall survival and toxicity according to age. RESULTS ORR for elderly and young patients were 34.9% and 44.7%, respectively (p=0.081). Median TTP did not differ between the two groups: 8.3 months for patients > or =70 years and 9.6 months for those <70 years (p=0.114). Median OS was 16.8 months and 20.5 months for the > or =70 and <70 years groups, respectively (p=0.74). With XELOX, mild paresthesia and an increase in transaminase levels were more frequent for young patients, whereas grade 3/4 diarrhea was higher in those > or =70 years (25% vs. 8%, p=0.005). For FUOX, only paresthesia was significantly lower in patients > or =70 years (53% vs. 71%, p=0.032). CONCLUSION Elderly patients with MCRC benefit from first-line oxaliplatin-fluoropyrimidine combinations as much as younger patients, without increased toxicity.

Increased levels of copper efflux transporter ATP7B are associated with poor outcome in colorectal cancer patients receiving oxaliplatin-based chemotherapy.

Recently, the copper efflux transporters ATP7B and ATP7A have been implicated in the transport of and resistance to platinum drugs in breast and ovarian cancers. Because of the extensive use of oxaliplatin in colorectal cancer (CRC), we examined the expression of both transporters in tumors from CRC patients treated with oxaliplatin/5FU and sought to determine whether their expression can predict clinical outcome in these patients. ATP7B and ATP7A levels were determined by quantitative real‐time PCR in 50 primary tumors of previously untreated patients with advanced colorectal adenocarcinoma who were subsequently treated with oxaliplatin/5FU. Additionally, ATP7B protein expression was assessed by immunohistochemical staining using a tissue microarray. Patients with the lowest mRNA expression levels of ATP7B had a significantly longer time to progression (TTP) (p = 0.0009) than patients with the highest levels (12.14 months vs. 6.43 months) who also had an increased risk of progression (HR = 3.56; 95% CI, 1.6–7.9; p = 0.002). Furthermore, patients with low levels of both protein and mRNA of ATP7B derived the maximum benefit from oxaliplatin/5FU with the longest TTP as compared with patients with high levels of ATP7B protein and mRNA (14.64 months vs. 4.63 months, respectively, p = 0.01) and showed a nonsignificant trend toward a lower response rate (37.5% and 75%, respectively). In conclusion, ATP7B mRNA and protein expression in colorectal tumors is associated with clinical outcome to oxaliplatin/5FU. Prospective studies are required to evaluate the role of this marker in tailoring chemotherapy.

Pharmacogenomic strategies for developing customized chemotherapy in non-small cell lung cancer

In this review, we deal with six groups of cytotoxic drugs commonly used in the treatment of non-small cell lung cancer (NSCLC). Although there are many reviews of thymidylate synthase (TS) and antifolate inhibitors, in this article, we have tried to highlight aspects that are more important for medical oncologists to consider when treating NSCLC patients. There is compelling evidence that TS gene transcripts and TS polymorphisms could be used to decide which patients can best benefit from adjuvant chemotherapy approaches, especially in colorectal cancer, and not less importantly, to tailor chemotherapy in metastatic NSCLC when using drugs akin to fluorouracil, such as pemetrexed. Secondly, cisplatin is central to chemotherapy combinations and evidence indicates that DNA repair capacity influences response to cisplatin-based regimens. ERCC1 gene transcript stands out as a predictive marker of cisplatin sensitivity. Thirdly, preliminary studies indicate that upregulation of beta-tubulin III correlates with response to paclitaxel and vinorelbine. Fourthly, overexpression of ribonucleotide reductase can influence response to gemcitabine. Fifthly, we describe mechanisms of resistance to topoisomerase I inhibitors, although this subject has not yet been completely elucidated. Finally, to understand the mechanisms of resistance to EGF-R inhibitors, which have been shown to be useful in many different types of cancer, the Src-STAT signaling pathways are described here in detail. Hopefully, the assessment of Src and of STAT-3 can be implemented as predictive markers.

Cytotoxic Effects of Topotecan Combined with Various Active G2/M-Phase Anticancer Drugs in Human Tumor-Derived Cell Lines

Topotecan (TPT) is a DNA-Topoisomerase I poison that exhibitsantitumor activity. TPT, like other DNA-damaging agents, arrests ordelays cell cycle progression during S- and G2-phase in a widevariety of tumor-derived cell lines. Particularly, the G2-arrest gives time for the cell to repair its DNA lesions prior tostarting a new cell cycle. Based on these observations, we assessedthe interaction between TPT and G2/M-active agents in p53–mutatedcell lines of diverse origin in order to achieve cell toxicity. Two short-term sequential schedules were administered(TPT → G2/M-active drug at the interval of greatest TPT-inducedG2/M-phase cell arrest, and G2/M-active drug → TPT), in threehuman tumor-derived cell lines with proven sensitivity to the following drugs: Bleomycin in HEp-2 (squamous larynx carcinoma);Docetaxel in SKBr-3 (breast adenocarcinoma); Etoposide in NCI-H23(non-small-cell lung cancer). Our results show that: 1) SequentialTPT → G2/M-active drugs are synergistic when administrationoverlapped the maximum percentage of TPT-induced G2/M–phase cellarrest interval in all three mutated p53 cell lines; 2) the reversesequential schedule (G2/M-active drug → TPT) was antagonistic,and being only additive for Etoposide → TPT association. Inconclusion, our findings further support the potential cytotoxicrole of TPT in combination with other active drugs when the correctschedule of administration is applied. In addition, they provide arationale for new applications in clinical trials using short-termsequential TPT → G2/M-active drugs.

Curcumin mediates oxaliplatin-acquired resistance reversion in colorectal cancer cell lines through modulation of CXC-Chemokine/NF-κB signalling pathway

Resistance to oxaliplatin (OXA) is a complex process affecting the outcomes of metastatic colorectal cancer (CRC) patients treated with this drug. De-regulation of the NF-κB signalling pathway has been proposed as an important mechanism involved in this phenomenon. Here, we show that NF-κB was hyperactivated in in vitro models of OXA-acquired resistance but was attenuated by the addition of Curcumin, a non-toxic NF-κB inhibitor. The concomitant combination of Curcumin + OXA was more effective and synergistic in cell lines with acquired resistance to OXA, leading to the reversion of their resistant phenotype, through the inhibition of the NF-κB signalling cascade. Transcriptomic profiling revealed the up-regulation of three NF-κB-regulated CXC-chemokines, CXCL8, CXCL1 and CXCL2, in the resistant cells that were more efficiently down-regulated after OXA + Curcumin treatment as compared to the sensitive cells. Moreover, CXCL8 and CXCL1 gene silencing made resistant cells more sensitive to OXA through the inhibition of the Akt/NF-κB pathway. High expression of CXCL1 in FFPE samples from explant cultures of CRC patients-derived liver metastases was associated with response to OXA + Curcumin. In conclusion, we suggest that combination of OXA + Curcumin could be an effective treatment, for which CXCL1 could be used as a predictive marker, in CRC patients.