ERCC1 Induction after Oxaliplatin Exposure May Depend on KRAS Mutational Status in Colorectal Cancer Cell Line: In Vitro Veritas

CRISPR/Cas9-mediated silencing of CD44: unveiling the role of hyaluronic acid-mediated interactions in cancer drug resistance

A comprehensive overview of CD44 (CD44 Molecule (Indian Blood Group)), a cell surface glycoprotein, and its interaction with hyaluronic acid (HA) in drug resistance mechanisms across various types of cancer is provided, where CRISPR/Cas9 gene editing was utilized to silence CD44 expression and examine its impact on cancer cell behavior, migration, invasion, proliferation, and drug sensitivity. The significance of the HA-CD44 axis in tumor microenvironment (TME) delivery and its implications in specific cancer types, the influence of CD44 variants and the KHDRBS3 (KH RNA Binding Domain Containing, Signal Transduction Associated 3) gene on cancer progression and drug resistance, and the potential of targeting HA-mediated pathways using CRISPR/Cas9 gene editing technology to overcome drug resistance in cancer were also highlighted.

Gene network analysis of oxaliplatin-resistant colorectal cancer to target a crucial gene using chitosan/hyaluronic acid/protamine polyplexes containing CRISPR-Cas9

Colorectal cancer (CRC) treatment is dramatically hampered by resistance to oxaliplatin alone or in the combination of irinotecan or 5-fluorouracil and leucovorin. This study aims to design and assess Chitosan/Hyaluronic Acid/Protamine sulfate (CS/HA/PS) polyplexes loaded with CRISPR plasmid for targeting a key gene in cancer drug resistance. Here, recent findings were considered to validate oxaliplatin-resistant CRC-related genes and systems biology approaches employed to detect the critical gene. The polyplexes were characterized according to particle size, zeta potential, and stability. Moreover, carrier toxicity and transfection efficiency were assessed on oxaliplatin-resistant HT-29 cells. The post-transfection evaluations were performed to confirm gene disruption-mediated CRISPR. Eventually, excision cross complementation group 1(ERCC1), a crucial member of the nucleotide excision repair pathway, was selected to be targeted using CRISPR/Cas9 to reverse oxaliplatin resistance in HT-29 cells. CS/HA/PS polyplexes containing CRISPR/Cas9 plasmid exhibited negligible toxicity and comparable transfection efficiency with Lipofectamine™. Following the efficient gene delivery, sequences in CRISPR/Cas9 target sites were altered, ERCC1 was downregulated, and drug sensitivity was successfully restored in oxaliplatin-resistant cells. Findings indicate that CS/HA/PS/CRISPR polyplexes provide a potential strategy for delivering cargo and targeting oxaliplatin resistance-related gene to manipulate drug resistance as a rising concern in cancer therapeutic approaches.

Validation of Genetic Markers Associated with Survival in Colorectal Cancer Patients Treated with Oxaliplatin-Based Chemotherapy

BACKGROUND

Associations between candidate genetic variants and treatment outcomes of oxaliplatin, a drug commonly used for colorectal cancer patients, have been reported but not robustly established. This study aimed to validate previously reported prognostic and predictive genetic markers for oxaliplatin treatment outcomes and evaluate additional putative functional variants.

METHODS

Fifty-three SNPs were selected based on previous reports (40 SNPs) or putative function in candidate genes (13 SNPs). We used data from 1,502 patients with stage II-IV colorectal cancer who received primary adjuvant chemotherapy, 37% of whom received oxaliplatin treatment. Multivariable Cox proportional hazards models for overall survival and progression-free survival were applied separately in stage II-III and stage IV patients. For predictive SNPs, differential outcomes according to the type of chemotherapy (oxaliplatin-based vs. others) were evaluated using an interaction term. For prognostic SNPs, the association was assessed solely in patients with oxaliplatin-based treatment.

RESULTS

Twelve SNPs were predictive and/or prognostic at P < 0.05 with differential survival based on the type of treatment, in patients with stage II-III (GSTM5-rs11807, ERCC2-rs13181, ERCC2-rs1799793, ERCC5-rs2016073, XPC-rs2228000, P2RX7-rs208294, HMGB1-rs1360485) and in patients with stage IV (GSTM5-rs11807, MNAT1-rs3783819, MNAT1-rs4151330, CXCR1-rs2234671, VEGFA-rs833061, P2RX7-rs2234671). In addition, five novel putative functional SNPs were identified to be predictive (ATP8B3-rs7250872, P2RX7-rs2230911, RPA1-rs5030755, MGMT-rs12917, P2RX7-rs2227963).

CONCLUSIONS

Some SNPs yielded prognostic and/or predictive associations significant at P < 0.05, however, none of the associations remained significant after correction for multiple testing.

IMPACT

We did not robustly confirm previously reported SNPs despite some suggestive findings but identified further potential predictive SNPs, which warrant further investigation in well-powered studies.

Irinotecan or Oxaliplatin: Which is the First Move for the Mate?

OBJECTIVES

The aim of the present review is to discuss the potential link between RAS, BRAF and microsatellite instability (MSI) mutational patterns and chemotherapeutic agent efficacy [Irinotecan (IRI) vs. Oxaliplatin (OXA)], and how this can potentially influence the choice of the chemotherapy backbone.

METHODS

Following a review of the research literature, all pertinent articles published in the core journals were selected for the study. The inclusion criteria regarded relevant clinical and pre-clinical studies on the topic of interest (Relationship of OXA and IRI to KRAS/BRAF mutations and MSI).

RESULTS

Excision repair cross complementation group 1 (ERCC1) expression is inhibited by KRAS mutation, making tumor cells more sensitive to OXA. Results from OPUS, COIN and PRIME trials support that no conclusive data are available for BRAF mutant population because of the small number of patients. Enhanced IRI cytotoxicity to MSI cell lines is due to the participation of some of the mismatch repair (MMR) components in various DNA repair processes and their role in the maintenance of the pro-apoptotic effect of IRI and G2/M cell arrest.

CONCLUSION

OXA and IRI are indispensable drugs for mCRC treatment and their selection must be as careful as that of targeted agents. We suggest taking into consideration the interaction between known genomic alterations and OXA and IRI activity to personalize chemotherapy in mCRC patients.

Advanced colorectal cancer subtypes (aCRCS) help select oxaliplatin-based or irinotecan-based therapy for colorectal cancer

Oxaliplatin (OX) and irinotecan (IRI) are used as key drugs for the first‐line treatment of metastatic colorectal cancer (mCRC). However, no biomarkers have been identified to decide which of the drugs is initially used. In this translational research (TR) of the TRICOLORE trial, the advanced colorectal cancer subtype (aCRCS) was analyzed as a potential biomarker for the selection of OX or IRI. We collected 335 (68.8%) formalin‐fixed, paraffin‐embedded (FFPE) primary tumor specimens from 487 patients registered in the TRICOLORE trial and performed direct sequencing and immunohistochemical staining of CRC‐related genes, comprehensive gene‐expression analysis, and genome‐wide methylation analysis. The progression‐free survival (PFS) of the IRI group was significantly better compared with the OX group in BRAF wild‐type (WT), PTEN‐positive, and aCRCS A1 patients. Among the molecular factors, aCRCS were only associated with the PFS of OX and IRI groups. The PFS of the IRI group was significantly better compared with the OX group in aCRCS A1 + B1 (hazard ratio [HR] = 0.58; 95% confidence interval [CI] = 0.41‐0.82; P = .0023). In contrast, the OX group had better PFS compared with the IRI group in aCRCS B2, although this was not statistically significant (HR = 1.66; 95% CI = 0.94‐2.96; P = .083). Nearly half of patients with mCRC (46.8%, aCRCS A1 + B1) respond well to IRI, while only about 18.5% (aCRCS B2) of patients with mCRC responded well to OX. In conclusion, the aCRCS might be a predictive factor for the clinical outcomes of OX‐based and IRI‐based therapies.

Clinical significance of enterocyte-specific gene polymorphisms as candidate markers of oxaliplatin-based treatment for metastatic colorectal cancer

Colorectal cancer (CRC) can be classified into subtypes based on gene expression signatures. Patients with stage III enterocyte subtype of the CRC Assigner classifier have been shown to benefit from oxaliplatin adjuvant therapy. Here, we investigated whether single nucleotide polymorphisms (SNPs) in two enterocyte subtype-related genes, MS4A12 and CDX2, could predict the efficacy of oxaliplatin in first-line treatment for patients with metastatic CRC (mCRC). Three cohorts of patients were included: a discovery cohort receiving FOLFOX ± bevacizumab (BEV) (n = 146), a validation cohort receiving FOLFOXIRI + BEV (n = 230), and a control cohort receiving FOLFIRI + BEV (n = 228). SNPs were analyzed by PCR-based direct sequencing. In the discovery cohort, MS4A12 rs4939378 and CDX2 rs3812863 were identified as potential markers of efficacy. In the validation cohort, any G allele of MS4A12 rs4939378 was associated with longer progression-free survival (PFS) than the A/A variant in both univariate analysis (12.4 vs. 10.9 months, hazard ratio [HR] 0.70, 95% confidence interval [CI] 0.49-0.99, P = 0.033) and multivariable analysis (HR 0.65, 95%CI 0.44-0.97, P = 0.035) in patients expressing wild-type KRAS, but not mutant KRAS. In contrast, longer PFS was observed for patients expressing the CDX2 rs3812863 G/G variant than any A allele in univariate analysis (32.3 vs. 10.3 months, HR 0.39, 95%CI 0.19-0.81, P = 0.004) only in patients expressing mutant KRAS. These findings were not observed in the control cohort. Thus, MS4A12 and CDX2 SNPs may have utility as predictive biomarkers of response to oxaliplatin-based treatment in mCRC patients.

Single Nucleotide Polymorphisms in MiRNA Binding Sites of Nucleotide Excision Repair-Related Genes Predict Clinical Benefit of Oxaliplatin in FOLFOXIRI Plus Bevacizumab: Analysis of the TRIBE Trial

Background: The nucleotide excision repair (NER) pathway participates in platinum-induced DNA damage repair. Single nucleotide polymorphisms (SNPs) in miRNA-binding sites in the NER genes RPA2 and GTF2H1 are associated with the risk of colorectal cancer (CRC). Here, we analyzed whether RPA2 and GTF2H1 SNPs predict the efficacy of oxaliplatin in metastatic CRC (mCRC) patients. Patients and methods: Genomic DNA was extracted from blood samples from 457 patients with mCRC enrolled in the TRIBE trial, which compared first-line FOLFOXIRI plus bevacizumab (BEV) (n = 230, discovery cohort) and first-line FOLFIRI plus BEV (n = 227, control cohort). SNPs were analyzed by PCR-based direct sequencing. Results: In the FOLFOXIRI + BEV-treated cohort expressing wild-type KRAS, progression-free survival (PFS) was shorter for the RPA2 rs7356 C/C variant subgroup than the any T allele subgroup in univariate analysis (9.1 versus 13.3 months respectively, hazard ratio (HR) 2.32, 95% confidence interval (CI): 1.07–5.03, p = 0.020) and this remained significant in multivariable analysis (HR 2.97, 95%CI: 1.27–6.94, p = 0.012). A similar trend was observed for overall survival. In contrast, patients expressing mutant RAS and RPA2 rs7356 C/C variant had longer PFS with FOLFOXIRI + BEV than with FOLFIRI + BEV (12.1 versus 7.6 months, HR 0.23, 95%CI: 0.09–0.62, p = 0.002) but no superiority of FOLFOXIRI + BEV was observed for the RAS mutant, RPA2 rs7356 any T variant subgroup (11.7 versus 9.6 months, HR 0.77, 95%CI: 0.56–1.07, p = 0.12) or the RAS wild-type, RPA2 rs7356 C/C variant subgroup. Conclusion: RPA2 SNPs may serve as predictive and prognostic markers of oxaliplatin responsiveness in a RAS status-dependent manner in mCRC patients receiving FOLFOXIRI + BEV.

The interference between oxaliplatin & anti-EGFR therapies: a different hypothesis to explain the 'unexplainable'

This paper has been written because we have a differing idea concerning the suspected negative interference between oxaliplatin and anti-EGFR therapies in cancer patients. Several multicenter, randomized, controlled clinical trials investigated whether the efficacy of oxaliplatin-based chemotherapy is improved by the addition of anti-EGFR therapies in patients affected by KRAS wild-type advanced colorectal cancer. Results of these trials have produced puzzling findings, with some studies demonstrating improved survival and other studies showing no differences in overall survival between experimental and control arms. Moreover, a detrimental effect has been demonstrated in some settings. Nevertheless, the extent of this interaction remains uncertain. Some physicians proposed personal interpretations. This paper describes our hypothesis.

Analysis of Mutational Spectra in Metastatic Colorectal Carcinoma: KRAS as an Indicator of Oxaliplatin-Based Chemotherapy

Objective:

Mutation spectra in colorectal cancer with metastasis and its response to chemotherapy.

Summary of Background Data:

No molecular markers are available for selecting the optimal chemotherapeutic regimen (irinotecan or oxaliplatin) for metastatic colorectal cancer (mCRC).

Methods:

We enrolled 161 mCRC patients who underwent surgery for their primary tumors at Taipei Veterans General Hospital from 2004 to 2010. The prevalence of gene mutations was measured and correlated with responses to different cytotoxic agents.

Results:

We detected 1,836 mutations in 12 genes. KRAS mutants affected 44.3% of the tumors. The rate of good response was insignificantly higher for patients with KRAS mutant tumors who received oxaliplatin-based chemotherapy compared with patients with KRAS wild-type tumors (65.6% versus 47.0%; P = 0.15). For patients who received irinotecan-based chemotherapy, the rate of good response was similar in patients with wild-type (55.0%; n = 11) and those with KRAS mutant tumors (54.5%; n = 12; P = 1). In patients with KRAS mutant tumors treated with an oxaliplatin-based regimen, the overall survival was 38.5 months (95% CI: 26.6–50.5 months), which was insignificantly better than that for patients treated with an irinotecan-based regimen (30.4 months; 95% CI: 15.8–45.1 months; P = 0.206).

Conclusions:

Our data could not come to the conclusion that patient with KRAS mutation mCRC may have better response with oxaliplatin-based first-line chemotherapy. Further study is needed to confirm the relationship between gene mutation and chemotherapy response.

Using patient-derived xenograft models of colorectal liver metastases to predict chemosensitivity

BACKGROUND

Few in vivo models for colorectal cancer have been demonstrated to show external validity by accurately predicting clinical patient outcomes. Patient-derived xenograft (PDX) models of cancer have characteristics that might provide a form of translational research leading to personalized cancer care. The aim of this pilot study was to assess the feasibility of using PDXs as a platform for predicting patient colorectal liver metastases responses, in this case by correlating PDX and patient tumor responses to either folinic acid, fluorouracil plus oxaliplatin or folinic acid, fluorouracil plus irinotecan-based regimens.

METHODS

Sixteen patients underwent potentially curative resection of colorectal liver metastases, and tumors were grafted into NOD.CB17-Prkdc^scid/Arc mice. Mice were divided into groups to determine relative tumor growth in response to treatment. Tumors were analyzed by immunohistochemistry for Ki67 and Excision repair cross-complementation group 1.

RESULTS

An engraftment rate of 81% was achieved. Overall, there was a 67% positive match rate between eligible patient and PDX chemosensitivity profiles. There was a significant difference in relative decrease in Ki67 expression between sensitive/stable versus resistant PDXs for both treatment regimens. There was no statistically significant correlation between baseline ERCC1 expression and response to Oxaliplatin + 5-Fluorouracil in the PDXs.

CONCLUSIONS

This pilot study supports the feasibility of using PDX models of advanced colorectal cancer in larger studies to potentially predict patient chemosensitivity profiles.

ESMO consensus guidelines for the management of patients with metastatic colorectal cancer

Colorectal cancer (CRC) is one of the most common malignancies in Western countries. Over the last 20 years, and the last decade in particular, the clinical outcome for patients with metastatic CRC (mCRC) has improved greatly due not only to an increase in the number of patients being referred for and undergoing surgical resection of their localised metastatic disease but also to a more strategic approach to the delivery of systemic therapy and an expansion in the use of ablative techniques. This reflects the increase in the number of patients that are being managed within a multidisciplinary team environment and specialist cancer centres, and the emergence over the same time period not only of improved imaging techniques but also prognostic and predictive molecular markers. Treatment decisions for patients with mCRC must be evidence-based. Thus, these ESMO consensus guidelines have been developed based on the current available evidence to provide a series of evidence-based recommendations to assist in the treatment and management of patients with mCRC in this rapidly evolving treatment setting.

BRAF in metastatic colorectal cancer: the future starts now

BRAF mutations are detectable in about 5-15% of metastatic colorectal cancer (mCRC) patients and represent a clear negative prognostic factor. While in BRAF-mutated (BRAFmt) metastatic melanoma TKI target therapies (BRAF and MEK inhibitor), both alone or in combination, have shown significant efficacy, in BRAFmt CRC single-agent BRAF-inhibitors as well as chemotherapy seem to be ineffective. The critical role of EGFR in CRC and its multiple downstreaming pathways seem to be involved in this lack of response. In recent years, preclinical investigations and retrospective studies slowly increased our knowledge on BRAFmt CRC. This review analyses preclinical data and discusses several clinical trials in order to explore new therapeutic strategies targeting BRAFmt mCRC.

Tumor-Related Molecular Mechanisms of Oxaliplatin Resistance

Oxaliplatin was the first platinum drug with proven activity against colorectal tumors, becoming a standard in the management of this malignancy. It is also considered for the treatment of pancreatic and gastric cancers. However, a major reason for treatment failure still is the existence of tumor intrinsic or acquired resistance. Consequently, it is important to understand the molecular mechanisms underlying the appearance of this phenomenon to find ways of circumventing it and to improve and optimize treatments. This review will be focused on recent discoveries about oxaliplatin tumor-related resistance mechanisms, including alterations in transport, detoxification, DNA damage response and repair, cell death (apoptotic and nonapoptotic), and epigenetic mechanisms.