Mutational profiles of metastatic colorectal cancer treated with FOLFIRI plus cetuximab or bevacizumab before and after secondary resection ( AIO KRK 0306; FIRE ‐3)

Purpose The Gruppo Oncologico Nord Ovest (GONO) conducted a phase III study comparing fluorouracil, leucovorin, oxaliplatin, and irinotecan (FOLFOXIRI [irinotecan 165 mg/m2 day 1, oxaliplatin 85 mg/m2 day 1, leucovorin 200 mg/m2 day 1, fluorouracil 3,200 mg/m2 48-hour continuous infusion starting on day 1, every 2 weeks]) with infusional fluorouracil, leucovorin, and irinotecan (FOLFIRI). Methods Selection criteria included unresectable metastatic colorectal cancer, age 18 to 75 years, and no prior chemotherapy for advanced disease. The primary end point was response rate (RR). Results A total of 244 patients were randomly assigned. An increase of grade 2 to 3 peripheral neurotoxicity (0% v 19%; P < .001), and grade 3 to 4 neutropenia (28% v 50%; P < .001) were observed in the FOLFOXIRI arm. The incidence of febrile neutropenia (3% v 5%) and grade 3 to 4 diarrhea (12% v 20%) were not significantly different. Responses, as assessed by investigators, were, for FOLFIRI and FOLFOXIRI, respectively, complete, 6% and 8%; and partial, 35% and 58%, (RR, 41% v 66%; P = .0002). RR confirmed by an external panel was 34% versus 60% (P < .0001). The R0 secondary resection rate of metastases was greater in the FOLFOXIRI arm (6% v 15%; P = .033, among all 244 patients; and 12% v 36%; P = .017 among patients with liver metastases only). Progression-free survival (PFS) and overall survival (OS) were both significantly improved in the FOLFOXIRI arm (median PFS, 6.9 v 9.8 months; hazard ratio [HR], 0.63; P = .0006; median OS, 16.7 v 22.6 months; HR, 0.70; P = .032). Conclusion The FOLFOXIRI regimen improves RR, PFS, and OS compared with FOLFIRI, with an increased, but manageable, toxicity in patients with metastatic colorectal cancer with favorable prognostic characteristics. Further studies of FOLFOXIRI in combination with targeted agents and in the neoadjuvant setting are warranted.

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Dynamics and characteristics of KRAS mutated circulating tumor DNA in patients with metastatic colorectal cancer during various treatments.

Journal of Clinical Oncology ◽

10.1200/jco.2018.36.4_suppl.665 ◽

2018 ◽

Vol 36 (4_suppl) ◽

pp. 665-665

Author(s):

Yuji Takayama ◽

Koichi Suzuki ◽

Kosuke Ichida ◽

Taro Fukui ◽

Nao Kakizawa ◽

...

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Disease Progression ◽

Kras Mutation ◽

Circulating Tumor Dna ◽

Line Treatment ◽

Tumor Tissues ◽

Significant Difference ◽

Before And After ◽

Tumor Dna

665 Background: KRAS mutated circulating tumor DNA (MctDNA) can be detected in blood of patients with metastatic colorectal cancer (mCRC) but its dynamics and characteristics during anti-EGFR and other treatments are not well known. Methods: Four hundred and fifty-one plasma samples were collected prospectively from 85 patients who underwent chemotherapy due to mCRC in 2014 - 2017. KRAS mutation in codon12/13/61 was explored in tumor tissues and plasma. Results: KRAS assessment in tumor tissues showed 29 patients with KRAS mutation (MT), 56 patients without mutation (WT). Sensitivity and specificity of MctDNA was 86.4% and 100%, respectively. In 29 patients with MT, significant difference in PFS was observed between patients with MctDNA and without during 1st line treatment (3.0 months vs.15.0 months; p = 0.005). In 56 patients with WT, 27 patients showed MctDNA during various treatments. Different characteristics in appearance were recognized during several treatments including anti-VEGF, TAS-102 and regorafenib. KRAS mutation in codon12/13 was appeared before and after disease progression. KRAS mutation in codon 61 was, however, frequently detected before disease progression. A spike like appearance of KRAS mutation in codon12/13 was likely seen in response to induction of the sequential treatment. Significant difference in PFS was observed between patients with MctDNA and without during 1st line treatment (6.0 months vs. 13.0 months; p = 0.0017), as was observed in patients with MT. Conclusions: Dynamics and characteristics of KRAS status in blood may be involved in the treatment response and outcome in mCRC patients.

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Efferent therapy in the first-line drug treatment of metastatic colorectal cancer

Medical Council ◽

10.21518/2079-701x-2018-10-172-175 ◽

2018 ◽

pp. 172-175

Author(s):

Z. S. Kotova ◽

T. Yu. Semiglazova ◽

I. A. Baldueva ◽

D. H. Latipova ◽

D. O. Yurlov ◽

...

Keyword(s):

Colorectal Cancer ◽

Drug Treatment ◽

Metastatic Colorectal Cancer ◽

Objective Response ◽

First Line ◽

Genetic Characteristics ◽

Significant Difference ◽

Before And After ◽

Line Drug

The aim of this study is to analyse the efficacy of efferent therapy (hemosorption) as part of drug treatment in patients with metastatic colorectal cancer (mCRC) based on the use of standard first-line chemotherapy combined with the bevacizumab biosimilar. The study included 54 patients with histologically verified mCRC who received the first-line FOLFOX + bevacizumab therapy in combination with and without hemosorption. All patients of the FOLFOX + bevacizumab (+) hemosorption group (n = 32) received the hemosorption using Hemophoenix apparatus on Day 4 of the cycle during the first 6 cycles. A total of 182 hemosorption procedures were performed. The control group included 22 patients receiving the FOLFOX + bevacizumab regimen without hemosorption. The bevacizumab biosimilar was introduced in both groups throughout the treatment at standard doses once every 2 weeks. There was no statistically significant difference between the study groups in the main clinical, pathomorphological, molecular genetic characteristics (sex, age, ECOG status, localization of primary tumor, tumor differentiation, RAS, BRAF mutations, microsatellite instability, etc.).Blood sampling to evaluate the effect of hemosorption on the pharmacokinetics (PK) of bevacizumab biosimilar was performed during the 2nd cycle before (PK1) and after (PK2) hemosorption procedures. The bevacizumab biosimilar concentration in the blood of patients before and after hemosorption showed no statistically significant difference (p = 0,423).The use of pharmaceutical treatment in the FOLFOX + bevacizumab (+) hemosorption group contributed to the achievement of an objective response (OR) in 62% of patients (p = 0.001). Median progression-free survival (PFS) was 10 ± 0.9 months [95% CI 8.3-11.7] in the FOLFOX + bevacizumab (+) hemosorption group, and 7 ± 0.5 months [95% CI 4.4-11.6] in the FOLFOX + bevacizumab (-) hemosorption group. There was no significant difference in PFS between the groups of patients treated with FOLFOX + bevacizumab regimen with and without hemosorption (p = 0.445).There were statistically significant differences in the frequency of nausea, diarrhoea and asthenia in the FOLFOX + bevacizumab (+) hemosorption group. The analysis of the dynamics of the quality of life (QoL) level before and after treatment showed that QoL level related to health (p = 0.0001) as well as the emotional (p = 0.0001) and social (p = 0,04) functioning increased in patients receiving the FOLFOX + bevacizumab regimen in combination with hemosorption, 0,039).Thus, the addition of hemosorption to the first-line drug treatment according to the FOLFOX + bevacizumab regimen does not affect bevacizumab pharmacokinetics, increases the frequency of objective response, reduces toxicity of the therapy and improves the quality of patients’ life indicators.

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Mechanism of bevacizumab-induced arterial hypertension: Relation with skin capillary rarefaction in patients treated for metastatic colorectal cancer

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.3557 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 3557-3557 ◽

Cited By ~ 4

Author(s):

J. F. Morere ◽

G. Des Guetz ◽

J. Mourad ◽

B. I. Lévy ◽

J. Breau

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Renin Angiotensin System ◽

Humoral Factors ◽

Doppler Flowmetry ◽

Capillary Rarefaction ◽

Before And After ◽

Grade 3 ◽

Microvascular Endothelial Function ◽

Microvascular Rarefaction

3557 Background: Bevacizumab in combination with chemotherapy is the standard treatment of metastatic colorectal cancer (mCRC). Hypertension (HT) has been reported in all studies, in particular grade 3 HT (3 - 16%) (Saif and Mehra, 2006 Expert Opinion on Drug Safety). The mechanism underlying bevacizumab-related HT is not yet clearly understood and recent studies have demonstrated that humoral factors involving the renin-angiotensin system and the sympathetic nervous system had little role in the observed increase in BP. As far as microvascular rarefaction has been reported in all forms of human and experimental HT, we tested the hypothesis that anti VEGF therapy could induce microvascular rarefaction in non tumoral tissues and, thus, result in an increase in BP Methods: For 16 patients treated for mCRC, Bevacizumab was administered at 5 or 7.5 mg/kg every 2 or 3 weeks depending on the frequency of concomitant chemotherapies which were FOLFIRI (4 patients) or XELOX (12 patients) We used intravital video-microscopy to measure basal and maximal (during venous congestion) skin capillary densities in the dorsum of the fingers. Aortic stiffness was evaluated using pulse wave velocity, and microvascular endothelial function was assessed by laser-Doppler flowmetry combined with iontophoresis of three different doses of acetylcholine (ACh). All measurements were performed in 16 patients (mean age: 59±10 y) before and after a 6 month treatment with bevacizumab (mean cumulative dose: 3.16±0.90 g) Results: are summarized in the following table : Conclusions: Pharmacological blockage of VEGF receptors result in endothelial dysfunction and capillary rarefaction in humans. Both changes are closely associated with and seem responsible for the rise in blood pressure observed in patients receiving this treatment. This could be considered for future study about anti- angiogenic treatment and HT. [Table: see text] No significant financial relationships to disclose.

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Relationship of Src activity and prior oxaliplatin on outcomes after hepatectomy for metastatic colorectal cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.15_suppl.3561 ◽

2012 ◽

Vol 30 (15_suppl) ◽

pp. 3561-3561

Author(s):

Van Karlyle Morris ◽

Nila Parikh ◽

Michael J. Overman ◽

Zhi-Qin Jiang ◽

Dipen M Maru ◽

...

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Epithelial To Mesenchymal Transition ◽

Automated Image Analysis ◽

Relapse Free Survival ◽

Free Survival ◽

Nonreceptor Tyrosine Kinase ◽

Mesenchymal Transition ◽

Before And After

3561 Background: The nonreceptor tyrosine kinase Src regulates pathways critical to tumor proliferation, chemoresistance, and epithelial-to-mesenchymal transition. In vitro, Src is activated after acute oxaliplatin exposure and in acquired oxaliplatin resistance, but not after 5-FU alone. Activation of Src and its substrate FAK in metastatic colorectal cancer treated with oxaliplatin has not been studied in human specimens. Methods: Samples from 170 hepatic resections from two cohorts of patients with metastatic colorectal cancer were examined by IHC for expression of activated Src (pSrc) and FAK (total and pFAK). In the first cohort (n=50), tissue was collected at consecutive hepatic resections before and after oxaliplatin. Patients in the second cohort (n=120) were compared based on whether or not oxaliplatin was administered after resection. IHC was graded semi-quantitatively, 0 to 4 based on intensity (first cohort), and by automated image analysis (second cohort). Results: In the first cohort, pFAK expression increased after oxaliplatin exposure (mean IHC score 2.04 vs. 1.18, p<0.01). In the second cohort, Src activation was correlated with pFAK expression (p<0.01). Patients pretreated with oxaliplatin demonstrated increased expression of activated FAK (p=0.02) compared to 5-FU alone or irinotecan regimens. There was a weak association between total Src expression and the number of oxaliplatin cycles (p=0.06). Among patients in the second cohort, five-year relapse-free survival was inversely related to levels of pFAK (21.1%, 16.5%, and 7.4% for low, medium, and high levels of pFAK, respectively; p=0.02) and of pSrc (19.6%, 13.6%, and 8.2% for low, medium, and high levels of pSrc, respectively; p= 0.01). Conclusions: Patients treated with neoadjuvant oxaliplatin demonstrated increased Src signaling in liver metastases, a finding associated with worse relapse-free survival. These results are consistent with prior in vitro studies correlating oxaliplatin exposure with Src pathway activation and support the idea that inhibition of Src, when used in combination with platinum chemotherapy, warrants further investigation in patients with metastatic colorectal cancer.

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CTLs/regulatory T-cells ratio as a prediction marker of chemotherapy in metastatic colorectal cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2013.31.15_suppl.e14684 ◽

2013 ◽

Vol 31 (15_suppl) ◽

pp. e14684-e14684

Author(s):

Teruo Sasatomi ◽

Takafumi Oochi ◽

Yutaka Ogata ◽

Yoshito Akagi ◽

Kazuo Shirouzu

Keyword(s):

Colorectal Cancer ◽

T Cells ◽

Regulatory T Cells ◽

Metastatic Colorectal Cancer ◽

Tumor Marker ◽

Cancer Patients ◽

Metastatic Lesion ◽

The Other ◽

Before And After ◽

Colorectal Cancer Patients

e14684 Background: Many multiple anti cancer drugs regimens have been established for metastaticcolorectal cancer recently. We investigated cellular immunoreaction of these patients to their cancer. Methods: 32 metastatic colorectal cancer patients have been started chemotherapies. Their PBMCs were harvested and investigated their character by Fac scan with fluorescent labeled antibodies (CD3,CD8, CD4, CD25, Foxp3) at before and after chemotherapy. Results: After chemotherapy, both CTLs(CD3, CD8 positive) and regulatory T cells (CD4, CD25, Foxp3 positive) were decreased in number among all patients. On the other hand, CTL/T reg ratio were significantly increased among tumor marker decreased patients and significantly decreased among tumor marker increased or stable patients. CEA levels among 85.7% of increased CTL/T reg ratio patients became to decrease less thanhalf. CEA levels among 66.7% of decreased CTL/T reg ratio patients became to increase or to be stable, if their regimens have not been changed. The Reactive Rate of chemotherapy of CTL/T reg ratio increased patients was significantly higher than that of ratio decreased or stable patients. (P=0.021) The Disease Control Rate of chemotherapy of CTL/T reg ratio increased patients was higher than that of ratio decreased patients. Both resectability rate of liver metastatic lesion and early tumor shrinkage rate were higher at the CTL/T reg ratio increased patients group than at the other patients group. Conclusions: We found that the CTL/T reg ratios of PBMC in metastatic colorectal cancer patients were useful for prediction of the effect of chemotherapy.

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Final results and OS of the randomized phase II VOLFI trial (AIO- KRK0109): mFOLFOXIRI + panitumumab versus FOLFOXIRI as first-line treatment in patients with RAS wild- type metastatic colorectal cancer (mCRC).

Journal of Clinical Oncology ◽

10.1200/jco.2019.37.15_suppl.3511 ◽

2019 ◽

Vol 37 (15_suppl) ◽

pp. 3511-3511 ◽

Cited By ~ 2

Author(s):

Michael Geissler ◽

Jorge Riera-Knorrenschild ◽

Uwe Marc Martens ◽

Swantje Held ◽

Jobst Greeve ◽

...

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Phase Ii ◽

Primary Endpoint ◽

Objective Response ◽

Open Label ◽

Secondary Resection ◽

Strong Trend ◽

Mutational Status ◽

Secondary Endpoints

3511 Background: This trial evaluated activity and safety of mFOLFOXIRI + panitumumab vs FOLFOXIRI in ECOG 0-1, primarily non-resectable mCRC patients. The final primary endpoint was presented at ASCO and ESMO 2018. Now we report for the first time the final results regarding OS and PFS. Methods: Prospective 2:1 randomized, controlled, open label multi-center, phase II trial comparing mFOLFOXIRI (Ox 85 mg/m2, Iri 150 mg/m2, 5-FU 3000mg/m2 cont. 48h, LV 200 mg/m2) + Panitumumab 6 mg/KG (arm A) with FOLFOXIRI (Ox 85 mg/m2, Iri 165 mg/m2, 5-FU 3200mg/m2 cont. 48h, LV 200 mg/m2; arm B), both arms q2w. Prospective strata were cohort 1: irresectable mCRC (n=65), and cohort 2: chance of secondary resection of metastatic lesions (n=31). Primary endpoint was ORR, secondary endpoints were secondary resection rate (cohort 2), DCR, PFS, OS, toxicity, quality of life (QLQ-C30). Financially supported by an unrestricted grant from Amgen. Results: A total of 96 patients were randomized (63 arm A, 33 arm B). ORR was 87.3% in arm A and 60.6% in arm B (p=0.0041, OR 4.47; 95%-CI 1.614-12.376). Secondary resections of metastases in the ITT population were observed in 33·3% (arm A Pmab) versus 12·1% (arm B) (OR=3.63; 95%-CI 1.13–11.67, p=0·029) and in cohort 2 in 75% (arm A Pmab) versus 36.4% (arm B) (OR=5.25; 95%-CI 1.07–25.8, p=0.05), respectively. Median PFS was similar in the study arms (9.7 mo in both arms, HR 1.071; 95%-CI 0.689-1.665, p=0.76). OS in the ITT population showed a strong trend in favour of the Pmab-containing arm A with a median OS of 35.7 mo compared to 29.8 mo in arm B (HR: 0·67; 95%-CI 0.41-1.11, P=0·12). mOS of cohort 2 was 52.0 mo in arm A versus 41.7 mo in arm B (HR 0.413; 95%-CI 0.15-1.12, p=0.07). Further results regarding to sidedness and BRAF mutational status will be presented. Conclusions: The addition of Pmab to a mFOLFOXIRI regimen in patients with RASwildtype metastatic colorectal cancer significantly improved objective response rate and the rate of secondary resection of metastases. Although PFS was comparable, there was a strong trend towards improved OS in the Pmab arm. Future studies are warranted to confirm this trend towards improved overall survival with this regimen. Clinical trial information: NCT01328171.

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Concordance ofKRAS/BRAFMutation Status in Metastatic Colorectal Cancer before and after Anti-EGFR Therapy

Journal of Oncology ◽

10.1155/2009/831626 ◽

2009 ◽

Vol 2009 ◽

pp. 1-9 ◽

Cited By ~ 15

Author(s):

S. Gattenlöhner ◽

B. Etschmann ◽

V. Kunzmann ◽

A. Thalheimer ◽

M. Hack ◽

...

Keyword(s):

Colorectal Cancer ◽

Targeted Therapy ◽

Metastatic Colorectal Cancer ◽

Kinase Inhibitors ◽

Standard Procedure ◽

Poor Response ◽

Genetic Alterations ◽

Primary Tumors ◽

Mutation Status ◽

Before And After

Anti-EGFR targeted therapy is a potent strategy in the treatment of metastatic colorectal cancer (mCRC) but activating mutations in theKRASgene are associated with poor response to this treatment. Therefore,KRASmutation analysis is employed in the selection of patients for EGFR-targeted therapy and various studies have shown a high concordance between the mutation status in primary CRC and corresponding metastases. However, although development of therapy related resistance occurs also in the context of novel drugs such as tyrosine kinase-inhibitors the effect of the anti-EGFR treatment on theKRAS/BRAFmutation status itself in recurrent mCRC has not yet been clarified. Therefore, we analyzed 21 mCRCs before/after anti-EGFR therapy and found a pre-/posttherapeutic concordance of theKRAS/BRAFmutation status in 20 of the 21 cases examined. In the one discordant case, further analyses revealed that a tumor mosaicism or multiple primary tumors were present, indicating that anti-EGFR therapy has no influence onKRAS/BRAFmutation status in mCRC. Moreover, as the preselection of patients with aKRASwtgenotype for anti-EGFR therapy has become a standard procedure, sample sets such ours might be the basis for future studies addressing the identification of potential anti-EGFR therapy induced genetic alterations apart fromKRAS/BRAFmutations.

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Treatment of metastatic colorectal cancer with aimpila, a glycoside/alpha-fetoprotein complex

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.3589 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 3589-3589 ◽

Cited By ~ 1

Author(s):

V. Pak ◽

O. Molchanov ◽

M. Vincent

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Mitochondrial Permeability Transition ◽

Performance Status ◽

Single Agent ◽

Alpha Fetoprotein ◽

Ct Scans ◽

Ecog Performance Status ◽

Eligibility Criteria ◽

Before And After

3589 Background: Aimpila is a non-covalent complex of two natural compounds: porcine alpha-fetoprotein (PAFP) and a glycosidic apoptosis inducer (AI). PAFP is able to bind selectively to the AFP receptor-positive cancer cells and deliver the AI intracellularly due to AFP receptor-mediated endocytosis. The AI opens mitochondrial permeability transition pores, resulting in apoptosis. Preclinically, the complex is cytotoxic. We investigated the single agent activity of aimpila in patients (pts) with liver metastatic colorectal cancer (mCRC). Methods: Eligibility Criteria: Age >18 yrs, mCRC, any prior treatment, having documented progressive metastatic liver disease. Treatment consisted of oral capsules at a fixed sub-maximal dose (0.3 mg of active substance in an oral capsule, twice a day for 8 weeks). 12 pts were accrued, 6 chemonaïve; median ECOG performance status was 0, median age 56 years (range 45–65), and median time from previous treatment failure was 9.0 months (range 1–20). CT scans were performed before and after. Results: Of the 12 patients, 9 are evaluable for response by RECIST. Two achieved a complete response (CR), 1 a partial response (PR); subsequent confirmatory CT scans are pending. Three achieved stabilization (SD), in 2 cases = 2 months; 3 experienced disease progression. Of 3 non-evaluable pts, 1 experienced clinical deterioration without a CT scan, 1 experienced stable disease >2 months but with both lesions <10 mm in diameter, and a third developed nausea and vomiting leading to interruption of treatment, the only recorded significant adverse event. CEA estimations before and after treatment are available from 2 pts; 1 pt (radiological CR) going from 816 ng/ml to 268 ng/ml; the other (radiological SD) going from 1,243 ng/ml to 638 ng/ml. In this latter patient, one of the liver lesions disappeared, radiologically. The PR pt and 1 of the SD pts had progressed after previous oxaliplatin-based chemotherapy. Median survival has not yet been reached, with a median follow-up of 4 months. Conclusion: Single agent aimpila was well-tolerated in this patient population and produced major objective responses in some patients with liver mCRC. Further study is warranted. [Table: see text]

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ERCC1, KRAS mutation, and oxaliplatin sensitivity in colorectal cancer: Old dogs and new tricks.

Journal of Clinical Oncology ◽

10.1200/jco.2012.30.4_suppl.489 ◽

2012 ◽

Vol 30 (4_suppl) ◽

pp. 489-489 ◽

Cited By ~ 3

Author(s):

Armando Orlandi ◽

Mariantonietta Di Salvatore ◽

Michele Basso ◽

Cinzia Bagalà ◽

Antonia Strippoli ◽

...

Keyword(s):

Colorectal Cancer ◽

Metastatic Colorectal Cancer ◽

Cell Line ◽

Cell Lines ◽

Predictors Of Response ◽

Mutational Status ◽

Retrospective Clinical Study ◽

Significant Difference ◽

Before And After ◽

The Impact

489 Background: Oxaliplatin is widely used in metastatic colorectal cancer, but currently there are not valid predictors of response to this drug. In our recent retrospective clinical study we have shown a greater efficacy of Oxaliplatin in patients with metastatic colorectal cancer with mutated (mt) K-RAS. We hypothesized that the mutational status of K-RAS could influence the expression of ERCC1, one of the main mechanisms of Oxaliplatin resistance. Methods: We used four cell lines of colorectal cancer: two K-RAS wild type (wt) (HCT-8 and HT-29) and two K-RAS mt (SW620 and SW480). We evaluated the sensitivity of these cell lines to Oxaliplatin by MTT-test and the ERCC1 levels before and after 24 h exposure to Oxaliplatin by Real-Time PCR. We silenced K-RAS in a K-RAS mt cell line to evaluate the impact on Oxaliplatin sensitivity and ERCC1 levels. We also silenced ERCC1 in order to confirm the importance of this protein as a Oxaliplatin resistance factor. Results: The K-RAS mt cell lines were more sensitive to Oxaliplatin (OR 2.68; IC 95% 1.511-4.757 p<0.001). The basal levels of ERCC1 did not show significant differences between K-RAS mt and wt cell line, however, after 24 h exposure to Oxaliplatin, only the K-RAS wt lines showed the ability to induce ERCC1, with a statistically significant difference (OR 42.9 IC 95% 17.260-106.972 p<0.0005). The silencing of K-RAS in K-RAS mt cell lines demonstrated to reduce sensitivity to Oxaliplatin associated with the acquisition of the ability to induce ERCC1. The silencing of ERCC1 in K-RAS wt cell lines enhance the sensibility to Oxaliplatin. Conclusions: The K-RAS mutated cell lines were more sensitive to Oxaliplatin. This feature seems to be secondary to the inability of these cells to induce ERCC1 after exposure to Oxaliplatin. K-RAS can thus be a predictor of response to Oxaliplatin in colorectal cancer representing a surrogate for ability to induce ERCC1.

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