Oxaliplatin retreatment in metastatic colorectal cancer: Systematic review and future research opportunities

MDFI promotes the proliferation and tolerance to chemotherapy of colorectal cancer cells by binding ITGB4/LAMB3 to activate the AKT signaling pathway

Colorectal cancer (CRC) is one of the most lethal cancers. Single-cell RNA sequencing (scRNA-seq) and protein-protein interactions (PPIs) have enabled the systematic study of CRC. In our research, the activation of the AKT pathway in CRC was analyzed by KEGG using single-cell sequencing data from the GSE144735 dataset. The correlation and PPIs of MDFI and ITGB4/LAMB3 were examined. The results were verified in the TCGA and CCLE and further tested by coimmunoprecipitation experiments. The effect of MDFI on the AKT pathway via ITGB4/LAMB3 was validated by knockdown and lentiviral overexpression experiments. The effect of MDFI on oxaliplatin/fluorouracil sensitivity was probed by colony formation assay and CCK8 assay. We discovered that MDFI was positively associated with ITGB4/LAMB3. In addition, MDFI was negatively associated with oxaliplatin/fluorouracil sensitivity. MDFI upregulated the AKT pathway by directly interacting with LAMB3 and ITGB4 in CRC cells, and enhanced the proliferation of CRC cells via the AKT pathway. Finally, MDFI reduced the sensitivity of CRC cells to oxaliplatin and fluorouracil. In conclusion, MDFI promotes the proliferation and tolerance to chemotherapy of colorectal cancer cells, partially through the activation of the AKT signaling pathway by the binding to ITGB4/LAMB3. Our findings provide a possible molecular target for CRC therapy.

Trifluridine-tipiracil plus bevacizumab versus trifluridine-tipiracil monotherapy for chemorefractory metastatic colorectal cancer: a systematic review and meta-analysis

Colorectal cancer is the leading cause of cancer death worldwide. The first and second lines of treatment for metastatic colorectal cancer (mCRC) include chemotherapy based on 5-fluorouracil. However, treatment following progression on the first and second line is still unclear. We searched PubMed, Scopus, Cochrane, and Web of Science databases for studies investigating the use of trifluridine-tipiracil with bevacizumab versus trifluridine-tipiracil alone for mCRC. We used RStudio version 4.2.3; and we considered p < 0.05 significant. Seven studies and 1,182 patients were included - 602 (51%) received trifluridine-tipiracil plus bevacizumab. Compared with control, the progression-free survival (PFS) (HR 0.52; 95% CI 0.42-0.63; p < 0.001) and overall survival (OS) (HR 0.61; 95% CI 0.52-0.70; p < 0.001) were significantly higher with bevacizumab. The objective response rate (ORR) (RR 3.14; 95% CI 1.51-6.51; p = 0.002) and disease control rate (DCR) (RR 1.66; 95% CI 1.28-2.16; p = 0.0001) favored the intervention. Regarding adverse events, the intervention had a higher rate of neutropenia (RR 1.38; 95% CI 1.19-1.59; p = 0.00001), whereas the monotherapy group had a higher risk of anemia (RR 0.60; 95% CI 0.44-0.82; p = 0.001). Our results support that the addition of bevacizumab is associated with a significant benefit in PFS, OS, ORR and DCR.

Upregulated lncRNA PRNT promotes progression and oxaliplatin resistance of colorectal cancer cells by regulating HIPK2 transcription

BACKGROUND

Colorectal cancer (CRC) is the third most common cancer and a significant cause of cancer-related mortality globally. Resistance to chemotherapy, especially during CRC treatment, leads to reduced effectiveness of drugs and poor patient outcomes. Long noncoding RNAs (lncRNAs) have been implicated in various pathophysiological processes of tumor cells, including chemotherapy resistance, yet the roles of many lncRNAs in CRC remain unclear.

AIM

To identify and analyze the lncRNAs involved in oxaliplatin resistance in CRC and to understand the underlying molecular mechanisms influencing this resistance.

METHODS

Gene Expression Omnibus datasets GSE42387 and GSE30011 were reanalyzed to identify lncRNAs and mRNAs associated with oxaliplatin resistance. Various bioinformatics tools were employed to elucidate molecular mechanisms. The expression levels of lncRNAs and mRNAs were assessed via quantitative reverse transcription-polymerase chain reaction. Functional assays, including MTT, wound healing, and Transwell, were conducted to investigate the functional implications of lncRNA alterations. Interactions between lncRNAs and transcription factors were examined using RIP and luciferase reporter assays, while Western blotting was used to confirm downstream pathways. Additionally, a xenograft mouse model was utilized to study the in vivo effects of lncRNAs on chemotherapy resistance.

RESULTS

LncRNA prion protein testis specific (PRNT) was found to be upregulated in oxaliplatin-resistant CRC cell lines and negatively correlated with homeodomain interacting protein kinase 2 (HIPK2) expression. PRNT was demonstrated to sponge transcription factor zinc finger protein 184 (ZNF184), which in turn could regulate HIPK2 expression. Altered expression of PRNT influenced CRC cell sensitivity to oxaliplatin, with overexpression leading to decreased sensitivity and decreased expression reducing resistance. Both RIP and luciferase reporter assays indicated that ZNF184 and HIPK2 are targets of PRNT. The PRNT/ZNF184/HIPK2 axis was implicated in promoting CRC progression and oxaliplatin resistance both in vitro and in vivo.

CONCLUSION

The study concludes that PRNT is upregulated in oxaliplatin-resistant CRC cells and modulates the expression of HIPK2 by sponging ZNF184. This regulatory mechanism enhances CRC progression and resistance to oxaliplatin, positioning PRNT as a promising therapeutic target for CRC patients undergoing oxaliplatin-based chemotherapy.

The Natural Product Secoemestrin C Inhibits Colorectal Cancer Stem Cells via p38-S100A8 Feed-Forward Regulatory Loop

Cancer stem cells (CSCs) are closely associated with tumor initiation, metastasis, chemoresistance, and recurrence, which represent some of the primary obstacles to cancer treatment. Targeting CSCs has become an important therapeutic approach to cancer care. Secoemestrin C (Sec C) is a natural compound with strong anti-tumor activity and low toxicity. Here, we report that Sec C effectively inhibited colorectal CSCs and non-CSCs concurrently, mainly by inhibiting proliferation, self-renewal, metastasis, and drug resistance. Mechanistically, RNA-seq analysis showed that the pro-inflammation pathway of the IL17 axis was enriched, and its effector S100A8 was dramatically decreased in Sec C-treated cells, whose roles in the stemness of CSCs have not been fully clarified. We found that the overexpression of S100A8 hindered the anti-CSCs effect of Sec C, and S100A8 deficiency attenuated the stemness traits of CSCs to enhance the Sec C killing activity on them. Meanwhile, the p38 signal pathway, belonging to the IL17 downstream axis, can also mediate CSCs and counter with Sec C. Notably, we found that S100A8 upregulation increased the p38 protein level, and p38, in turn, promoted S100A8 expression. This indicated that p38 may have a mutual feedback loop with S100A8. Our study discovered that Sec C was a powerful anti-colorectal CSC agent, and that the positive feedback loop of p38-S100A8 mediated Sec C activity. This showed that Sec C could act as a promising clinical candidate in colorectal cancer treatment, and S100A8 could be a prospective drug target.

Chemotherapy re-use versus anti-angiogenic monotherapy as the third-line treatment of patients with metastatic colorectal cancer: a real-world cohort study

BACKGROUND

There are various recommendations for third-line treatment in mCRC, however, there is no consensus on who is more suitable for particular strategy. Chemotherapy re-use in third-line setting is a common option in clinical practice. This study aimed to investigate the efficacy of third-line chemotherapy re-use by the comparison with that of anti-angiogenic monotherapy, and further find the population more suitable for third-line chemotherapy.

METHODS

Using electronic medical records of patients with mCRC, a retrospective cohort study was conducted. A total of 143 patients receiving chemotherapy and 40 patients receiving anti-angiogenic monotherapy in third-line setting as control group were retrospectively collected. Baseline characteristics were analyzed using the χ² test or the Fisher's exact test. ROC curve and surv_cutpoint function of 'survminer' package in R software were used to calculate the cut-off value. Survival curves were plotted with the Kaplan-Meier method and were compared using the log-rank test. The Cox proportional hazard regression model was used to analyze the potential risk factors.

RESULTS

A total of 143 patients receiving chemotherapy and 40 patients receiving anti-angiogenic monotherapy in third-line setting were retrospectively collected. Chemotherapy rechallenge was recorded in 93 patients (93/143, 65.0%), and the remaining patients chose new chemotherapeutic drugs that had not been previously used, including irinotecan-based (22/50), oxaliplatin-based (9/50), raltitrexed (9/50), gemcitabine (5/50) and other agents (5/50). The ORR and DCR of third-line chemotherapy reached 8.8%, 61.3%, respectively (anti-angiogenic monotherapy group: ORR 2.6%, DCR 47.4%). The mPFS and mOS of patients receiving chemotherapy were 4.9 and 12.0 m, respectively (anti-angiogenic monotherapy group: mPFS 2.7 m, mOS 5.2 m). Subgroup analyses found that patients with RAS/RAF mutation, longer PFS (greater than 10.6 m) in front-line treatment or larger tumor burden had better prognosis with third-line chemotherapy rather than anti-angiogenic monotherapy.

CONCLUSIONS

Third-line chemotherapy re-use was effective in mCRC. Those with more aggressive characteristics (RAS/RAF mutant, larger tumor burden) or better efficacy of previous chemotherapy (longer PFS) were more appropriate for third-line chemotherapy, rather than anti-angiogenic monotherapy.

PPP2R1B abolishes colorectal cancer liver metastasis and sensitizes Oxaliplatin by inhibiting MAPK/ERK signaling pathway

BACKGROUND

Patients with colorectal cancer (CRC) with liver metastasis or drug resistance have a poor prognosis. Previous research has demonstrated that PPP2R1B inactivation results in the development of CRC. However, the role of PPP2R1B in CRC metastasis and drug resistance is unclear.

METHODS

Venny 2.1 was used to determine the intersection between survival-related differentially expressed genes (DEGs) and liver metastasis-related DEGs according to RNA-seq data from The Cancer Genome Atlas (TCGA) and the GEO database (GSE179979). LC‒MS/MS and coimmunoprecipitation were performed to predict and verify the substrate protein of PPP2R1B. Gene Set Variation Analysis (GSVA) was subsequently utilized to assess pathway enrichment levels. The predictive performance of PPP2R1B was assessed by regression analysis, Kaplan-Meier (KM) survival analysis and drug sensitivity analysis. Immunohistochemistry (IHC), qRT-PCR and western blotting were performed to measure the expression levels of related mRNAs or proteins. Biological features were evaluated by wound healing, cell migration and invasion assays and CCK-8 assays. A mouse spleen infection liver metastasis model was generated to confirm the role of PPP2R1B in the progression of liver metastasis in vivo.

RESULTS

According to bioinformatics analysis, PPP2R1B is significantly associated with liver metastasis and survival in CRC patients, and these findings were further verified via immunohistochemistry (IHC), qPCR and Western blotting. Pathway enrichment and LC‒MS/MS analysis revealed that PPP2R1B is negatively associated with the MAPK/ERK signalling pathway. Additionally, PD98059, a MAPK/ERK pathway inhibitor, inhibited EMT in vitro by reversing the changes in key proteins involved in EMT signalling (ZEB1, E-cadherin and Snail) and ERK/MAPK signalling (p-ERK) mediated by PPP2R1B. Oxaliplatin sensitivity prediction and validation revealed that PPP2R1B silencing decreased Oxaliplatin chemosensitivity, and these effects were reversed by PD98059 treatment. Moreover, PPP2R1B was coimmunoprecipitated with p-ERK in vitro. A negative correlation between PPP2R1B and p-ERK expression was also observed in clinical CRC samples, and the low PPP2R1B/high p-ERK coexpression pattern indicated a poor prognosis in CRC patients. In vivo, PPP2R1B silencing significantly promoted liver metastasis.

CONCLUSIONS

This study revealed that PPP2R1B induces dephosphorylation of the p-ERK protein, inhibits liver metastasis and increases Oxaliplatin sensitivity in CRC patients and could be a potential candidate for therapeutic application in CRC.

Impact of Conventional and Potential New Metal-Based Drugs on Lipid Metabolism in Osteosarcoma MG-63 Cells

This work investigated the mechanisms of action of conventional drugs, cisplatin and oxaliplatin, and the potentially less deleterious drug Pd2Spermine (Spm) and its Pt(II) analog, against osteosarcoma MG-63 cells, using nuclear-magnetic-resonance metabolomics of the cellular lipidome. The Pt(II) chelates induced different responses, namely regarding polyunsaturated-fatty-acids (increased upon cisplatin), suggesting that cisplatin-treated cells have higher membrane fluidity/permeability, thus facilitating cell entry and justifying higher cytotoxicity. Both conventional drugs significantly increased triglyceride levels, while Pt2Spm maintained control levels; this may reflect enhanced apoptotic behavior for conventional drugs, but not for Pt2Spm. Compared to Pt2Spm, the more cytotoxic Pd2Spm (IC50 comparable to cisplatin) induced a distinct phospholipids profile, possibly reflecting enhanced de novo biosynthesis to modulate membrane fluidity and drug-accessibility to cells, similarly to cisplatin. However, Pd2Spm differed from cisplatin in that cells had equivalent (low) levels of triglycerides as Pt2Spm, suggesting the absence/low extent of apoptosis. Our results suggest that Pd2Spm acts on MG-63 cells mainly through adaptation of cell membrane fluidity, whereas cisplatin seems to couple a similar effect with typical signs of apoptosis. These results were discussed in articulation with reported polar metabolome adaptations, building on the insight of these drugs' mechanisms, and particularly of Pd2Spm as a possible cisplatin substitute.

Platinum-Based Twin Drug Modulates Tumor-Infiltrating Immune Cells to Improve Immune Checkpoint Blockade Therapy

Chemoimmunotherapy is an area of active research and development with a growing body of evidence supporting its potential benefits for the treatment of cancer. However, chemotherapy components of chemoimmunotherapy have several limitations, including systemic toxicity and poor performance in reversing the immunosuppressive tumor microenvironment. Here, we designed a twin drug, MROP, complexed with all-trans retinoic acid and oxaliplatin, and showed that the twin drug significantly enhanced the synergetic therapeutic efficacy with anti-PD-1 in a colorectal cancer mouse model. We demonstrated by mechanistic analyses of tumor tissue that the combination of anti-PD-1 and MROP induced immunogenic cell death and regulated tumor-infiltrating immune cells, including the polarization of tumor-associated macrophages toward type 1, a reduction in myeloid-derived suppressor cells, and a significant increase in the proportion of T cells, particularly CD8+ T cells. This paper provides a promising strategy for cancer treatment and new insight into the mechanism of chemoimmunotherapy.

TGM2, HMGA2, FXYD3, and LGALS4 genes as biomarkers in acquired oxaliplatin resistance of human colorectal cancer: A systems biology approach

Acquired resistance to oxaliplatin is considered as the primary reason for failure in colorectal cancer (CRC) therapy. Identifying the underlying resistance mechanisms may improve CRC treatment. The present study aims to identify the key genes involved in acquired oxaliplatin-resistant in CRC by confirming the oxaliplatin resistance index (OX-RI). To this aim, two public microarray datasets regarding oxaliplatin-resistant CRC cells with different OX-RI, GSE42387, and GSE76092 were downloaded from GEO database to identify differentially expressed genes (DEGs). The results indicated that the OX-RI affects the gene expression pattern significantly. Then, 54 common DEGs in both datasets including 18 up- and 36 down-regulated genes were identified. Protein-protein interaction (PPI) analysis revealed 13 up- (MAGEA6, TGM2, MAGEA4, SCHIP1, ECI2, CD33, AKAP12, MAGEA12, CALD1, WFDC2, VSNL1, HMGA2, and MAGEA2B) and 12 down-regulated (PDZK1IP1, FXYD3, ALDH2, CEACAM6, QPRT, GRB10, TM4SF4, LGALS4, ALDH3A1, USH1C, KCNE3, and CA12) hub genes. In the next step, two novel up-regulated hub genes including ECI2 and SCHIP1 were identified to be related to oxaliplatin resistance. Functional enrichment and pathway analysis indicated that metabolic pathways, proliferation, and epithelial-mesenchymal transition may play dominant roles in CRC progression and oxaliplatin resistance. In the next procedure, two in vitro oxaliplatin-resistant sub-lines including HCT116/OX-R4.3 and HCT116/OX-R10 cells with OX-IR 3.93 and 10.06 were established, respectively. The results indicated the up-regulation of TGM2 and HMGA2 in HCT116/OX-R10 cells with high OX-RI and down-regulation of FXYD3, LGALS4, and ECI2 in both cell types. Based on the results, TGM2, HMGA2, FXYD3, and LGALS4 genes are related to oxaliplatin-resistant CRC and may serve as novel therapeutic targets.

Trifluridine-Tipiracil and Bevacizumab in Refractory Metastatic Colorectal Cancer

BACKGROUND

In a previous phase 3 trial, treatment with trifluridine-tipiracil (FTD-TPI) prolonged overall survival among patients with metastatic colorectal cancer. Preliminary data from single-group and randomized phase 2 trials suggest that treatment with FTD-TPI in addition to bevacizumab has the potential to extend survival.

METHODS

We randomly assigned, in a 1:1 ratio, adult patients who had received no more than two previous chemotherapy regimens for the treatment of advanced colorectal cancer to receive FTD-TPI plus bevacizumab (combination group) or FTD-TPI alone (FTD-TPI group). The primary end point was overall survival. Secondary end points were progression-free survival and safety, including the time to worsening of the Eastern Cooperative Oncology Group (ECOG) performance-status score from 0 or 1 to 2 or more (on a scale from 0 to 5, with higher scores indicating greater disability).

RESULTS

A total of 246 patients were assigned to each group. The median overall survival was 10.8 months in the combination group and 7.5 months in the FTD-TPI group (hazard ratio for death, 0.61; 95% confidence interval [CI], 0.49 to 0.77; P<0.001). The median progression-free survival was 5.6 months in the combination group and 2.4 months in the FTD-TPI group (hazard ratio for disease progression or death, 0.44; 95% CI, 0.36 to 0.54; P<0.001). The most common adverse events in both groups were neutropenia, nausea, and anemia. No treatment-related deaths were reported. The median time to worsening of the ECOG performance-status score from 0 or 1 to 2 or more was 9.3 months in the combination group and 6.3 months in the FTD-TPI group (hazard ratio, 0.54; 95% CI, 0.43 to 0.67).

CONCLUSIONS

Among patients with refractory metastatic colorectal cancer, treatment with FTD-TPI plus bevacizumab resulted in longer overall survival than FTD-TPI alone. (Funded by Servier and Taiho Oncology; SUNLIGHT ClinicalTrials.gov number, NCT04737187; EudraCT number, 2020-001976-14.).

Emerging roles of non-coding RNAs in colorectal cancer oxaliplatin resistance and liquid biopsy potential

Colorectal cancer (CRC) is one of the most common malignancies of the digestive tract, with the annual incidence and mortality increasing consistently. Oxaliplatin-based chemotherapy is a preferred therapeutic regimen for patients with advanced CRC. However, most patients will inevitably develop resistance to oxaliplatin. Many studies have reported that non-coding RNAs (ncRNAs), such as microRNAs, long non-coding RNAs, and circular RNAs, are extensively involved in cancer progression. Moreover, emerging evidence has revealed that ncRNAs mediate chemoresistance to oxaliplatin by transcriptional and post-transcriptional regulation, and by epigenetic modification. In this review, we summarize the mechanisms by which ncRNAs regulate the initiation and development of CRC chemoresistance to oxaliplatin. Furthermore, we investigate the clinical application of ncRNAs as promising biomarkers for liquid CRC biopsy. This review provides new insights into overcoming oxaliplatin resistance in CRC by targeting ncRNAs.

Oxaliplatin inhibits colorectal cancer progression by inhibiting CXCL11 secreted by cancer-associated fibroblasts and the CXCR3/PI3K/AKT pathway

PURPOSE

Colorectal cancer (CRC) is a malignant tumor. Oxaliplatin (OXA) can inhibit cancer-associated fibroblasts (CAFs)-induced cancer progression. This study sought to explore the mechanism of OXA in CAFs-induced CRC development.

METHODS

CRC cell lines (Caco-2, SW620), normal fibroblasts (NFs), and CAFs were treated with OXA. NFs and CAFs were cultured. CAFs were treated with/without OXA (0.4 mM), and the supernatant was extracted as the conditioned medium (CM) to culture CRC cells. Cell malignant episodes, E-cadherin and Vimentin levels, CXCL1, CXCL2, CXCL3, CXCL8, and CXCL11 mRNA levels, CXCL11 protein level, and extracellular release were assessed. CAFs were transfected with interfering RNA sh-CXCL11 to silence CXCL11 or transfected with CXCL11 overexpression plasmids and treated with OXA to explore the role of CXCL11 in OXA-mediated CRC cells through CAFs. CXCL11 receptor CXCR3 levels in CRC cells and the PI3K/AKT pathway changes were examined. The xenogeneic tumor was transplanted in nude mice. CXCL11 and CXCR3 levels in tumor tissues, tumor volume, shape, size, weight, and Ki67 positive expressions were assessed.

RESULTS

CRC cell growths and epithelial-mesenchymal transformation were stimulated after culture with CAFs-CM, while OXA averted these trends. CXCL11 mRNA level was elevated most significantly, and its protein and extracellular secretion levels were raised, while OXA diminished the levels. CXCL11 silencing weakened the effects of CAFs-CM on promoting CRC proliferation and malignant episodes and CXCL11 overexpression averted OXA property on inhibiting CAFs-promoted CRC cell growth. CXCR3 and PI3K and AKT1 phosphorylation levels were raised in the CAFs-CM group but diminished by OXA. CXCL11 overexpression in CAFs averted OXA property on inhibiting CAFs-activated CXCR3/PI3K/AKT in CRC cells. OXA also inhibited the progression of xenograft tumors by limiting CAFs-secreted CXCL11.

CONCLUSIONS

OXA repressed CRC progression by inhibiting CAFs-secreted CXCL11 and the CXCR3/PI3K/AKT pathway.

Zuo Jin Wan Reverses the Resistance of Colorectal Cancer to Oxaliplatin by Regulating the MALAT1/miR-200s/JNK Signaling Pathway

Background

Oxaliplatin (L-OHP) is a common chemotherapy drug used in the treatment of colorectal cancer (CRC). Our previous work showed that Zuo Jin Wan (ZJW), a traditional Chinese medicine prescription, could improve sensitivity to L-OHP in the treatment of CRC, but the detailed mechanism is not clear. In previous mechanistic studies, we found that the miR-200s expression in CRC is associated with L-OHP sensitivity through regulation of MDR1/p-gp and the downstream c-JunN-terminal kinase (JNK) signaling pathway. Moreover, lncRNA-MALAT1 offers great potential in the regulation of drug resistance by interacting with miR-200s. Therefore, in this work, we explored whether ZJW could reverse L-OHP resistance in CRC by regulating MALAT1, miR-200s, and the downstream signaling pathway.

Methods

Cell Counting Kit-8 and flow cytometry were used to detect the effects of ZJW combined with L-OHP on chemotherapy tolerance and cell apoptosis of HCT116/L-OHP cells. Western blotting and quantitative real-time PCR (qRT-PCR) were used to detect the activation of the JNK signaling pathway and the protein and mRNA expression levels of the drug resistance-related MDR1/ABCB1 gene in HCT116/L-OHP cells treated with ZJW. The binding sites of MALAT1 and miR-200s were predicted by bioinformatics tools and confirmed by qRT-PCR. qRT-PCR was used to detect the expression of miR-200s and MALAT1 in HCT116/L-OHP cells treated with ZJW. A xenograft model of CRC in nude mice was established to observe the effect of ZJW combined with L-OHP on the growth of subcutaneously transplanted tumors. Apoptosis in tumor cells was detected by TUNEL staining. The activation of the JNK signaling pathway and the expression of drug resistance-related proteins were detected by immunohistochemistry and immunofluorescence. qRT-PCR was used to detect the expression of miR-200s and the MALAT1 gene in the tumors.

Results

Our study showed that ZJW could significantly decrease the proliferation and promote apoptosis of HCT116/L-OHP cells treated with L-OHP. We further proved that ZJW could reverse the drug resistance of HCT116/L-OHP cells by reducing MALAT1, indirectly upregulating miR-200s, alleviating the activation of the JNK signaling axis, and downregulating the expression of resistance proteins such as MDR1/ABCB1 and ABCG2. ZJW combined with L-OHP inhibited the growth of subcutaneously transplanted tumors and induced apoptosis in nude mice. ZJW reduced the expression of MALAT1 and upregulated the expression of miR-200s in transplanted tumors. In addition, ZJW also alleviated the activation of the JNK signaling pathway while reducing the expression of MDR1/ABCB1 and ABCG2.

Conclusions

Our study identified that MALAT1 promotes colorectal cancer resistance to oxaliplatin by reducing the miR-200s expression. ZJW may reverse chemoresistance by inhibiting the expression of MALAT1 and regulating the miR-200s/JNK pathway, providing an experimental basis for the clinical application of ZJW in relieving chemotherapy resistance.

Isolinderalactone sensitizes oxaliplatin-resistance colorectal cancer cells through JNK/p38 MAPK signaling pathways

BACKGROUND

Isolinderalactone (ILL), a sesquiterpene lactone compound, can be extracted from the root of Lindera aggregate. Physiological activities of ILL, including anti-inflammatory and anti-proliferative effects, have been investigated in multiple diseases. Nevertheless, little is known regarding its anti-cancer activities and the mechanism of action of ILL in targeting human CRC cells.

PURPOSE

To determine ILL-mediated anti-proliferative effects on oxaliplatin (Ox)-sensitive and resistant colorectal cancer (CRC) cells and underlying mechanisms involved in its effects focusing on signal transduction.

METHODS

Inhibitory effect of ILL on CRC cells was evaluated by analyzing mitochondrial membrane potential (MMP) dysfunction and multi-caspase activity. Apoptosis-regulating proteins and JNK/p38 signaling molecules were monitored by Western blotting. ROS-dependent physiological modifications by ILL were confirmed by pretreatment with N-acetylcysteine (NAC). Moreover, the involvement of JNK/p38 signaling in ROS-mediated apoptosis was verified by treatment with SP600125 (JNK inhibitor) and SB203580 (p38 inhibitor).

RESULTS

ILL decreased cell viability and colony formation in both CRC Ox-sensitive (HCT116 and HT29) and Ox-resistant (OxR) (HCT116-OxR and HT29-OxR) cells. ILL induced G2/M phase cell cycle arrest, ROS generation, phosphorylated (p)JNK/p38 MAPK activation, mitochondrial membrane potential (MMP) depolarization, and multi-caspase activation, which eventually triggered apoptotic cell death of CRC cells. In addition, combined treatment with ILL and SP600125, SB203580, or pan-caspase inhibitor (Z-VAD-FMK) prevented decreases in cell viability seen after treatment with ILL alone. Pretreatment with NAC attenuated ILL-mediated apoptosis, ROS production, and p-JNK/p38 expression.

CONCLUSION

Taken together, our results suggest that ILL can exert its anticancer effect in CRC Ox-sensitive and OxR cells by inducing ROS-mediated apoptosis through JNK/p38 MAPK signaling pathways. This is the first study demonstrating that ILL has a potential to improve drug efficacy against resistance mechanisms, providing a new insight into therapeutic strategies targeting drug-resistant CRC.

Liposomal oxaliplatin prodrugs loaded with metformin potentiate immunotherapy for colorectal cancer

Tumor hypoxia is confirmed to be associated with the formation of tumor immunosuppression, a general feature of solid tumors, and thus attenuates the effectiveness of various cancer therapies in clinic. We herein develop a tumor microenvironment (TME) modulating liposomal nanomedicine by encapsulating metformin with amphiphilic oxaliplatin prodrug constructed liposomes to potentiate cancer immunotherapy. While metformin could regulate metabolisms of tumor cells to reduce their oxygen consumption and relieve tumor hypoxia, oxaliplatin is a chemotherapy drug that induces immunogenic cell death (ICD). The obtained met-oxa(IV)-liposome upon intravenous injection effectively attenuates tumor hypoxia and induce ICD of cancer cells, thereby collectively suppresses the growth of murine colorectal tumors by eliciting potent antitumor immunity and reversing the immunosuppressive TME. As the result, the treatment with met-oxa(IV)-liposome effectively potentiates the immune checkpoint blockade (ICB) therapy against murine colorectal tumors. This liposomal nanomedicine is highlighted to be a TME modulating liposomal nanomedicine with high potency in suppressing tumor growth, particularly promising in synergizing with ICB therapy by boosting antitumor immune responses.

Lymphocyte antigen 6G6D-mediated modulation through p38α MAPK and DNA methylation in colorectal cancer

In addition to being novel biomarkers for poor cancer prognosis, members of Lymphocyte antigen-6 (Ly6) gene family also play a crucial role in avoiding immune responses to tumors. However, it has not been possible to identify the underlying mechanism of how Ly6 gene regulation operates in human cancers. Transcriptome, epigenome and proteomic data from independent cancer databases were analyzed in silico and validated independently in 334 colorectal cancer tissues (CRC). RNA mediated gene silencing of regulatory genes, and treatment with MEK and p38 MAPK inhibitors were also tested in vitro. We report here that the Lymphocyte antigen 6G6D is universally downregulated in mucinous CRC, while its activation progresses through the classical adenoma-carcinoma sequence. The DNA methylation changes in LY6G6D promoter are intimately related to its transcript regulation, epigenomic and histological subtypes. Depletion of DNA methyltransferase 1 (DNMT1), which maintains DNA methylation, results in the derepression of LY6G6D expression. RNA-mediated gene silencing of p38α MAPK or its selective chemical inhibition, however, reduces LY6G6D expression, reducing trametinib’s anti-inflammatory effects. Patients treated with FOLFOX-based first-line therapy experienced decreased survival due to hypermethylation of the LY6G6D promoter and decreased p38α MAPK signaling. We found that cancer-specific immunodominant epitopes are controlled by p38α MAPKs signaling and suppressed by DNA methylation in histological variants with Mucinous differentiation. This work provides a promising prospective for clinical application in diagnosis and personalized therapeutic strategies of colorectal cancer.

The structural maintenance of chromosomes 5 is a possible biomarker for individualized treatment of colorectal cancer

BACKGROUND

Although the understanding of resistance to oxaliplatin (OXA) chemotherapy in colorectal cancer (CRC) has been sought for many years, drug tolerance remains a major challenge for cancer therapy. Revealing the molecular mechanism of OXA resistance could help to explain the poor prognosis of patients.

METHODS

Gene expression omnibus (GEO) database was searched, GSE83129, which contains RNA profiling in metastatic CRC patients treated first-line with OXA, was chosen for the following analysis. Differential expressed genes (DEGs) between the adenocarcinoma and adjacent_normal team, respectively, in the OXA responders and no-responders were analyzed. The Gene Ontology (GO) and hub genes in the protein-protein interaction (PPI) network were used for the molecular mechanism of OXA resistance. Tumor-related databases were used for the clinical relevance of the structural maintenance of chromosomes 5 (SMC5) in CRC. The in vitro assays were used to detect the molecular function of SMC5 in CRC cells. Quantitative real-time PCR (qRT-PCR) and western blot were used to detect the expression of the structural maintenance of chromosomes 5/6 (SMC5/6) complex components upon OXA and raltitrexed (RTX) treatment. CCK-8 was used to detect the cell viability of cells with different treatment.

RESULTS

SMC5 was downregulated in CRC tissues of OXA no-response patients. Lower expression of SMC5 was correlated with a poor prognosis in CRC patients, improved this gene expression, inhibited the CRC cell growth and invasion in vitro. Furthermore, SMC5 was downregulated upon OXA treatment in CRC cells, while RTX would reverse its expression, and the combination of these two drugs restored the SMC5 level to the normal situation. Finally, RTX treatment enhanced the OXA cytotoxicity.

CONCLUSION

SMC5 is a tumor suppressor, that low expression of this gene is benefit for the development of CRC. Combination treatment with RTX and OXA may be more suitable for those OXA no-responders with lower SMC5.

Efficacy of Retreatment with Oxaliplatin-Based Regimens in Metastatic Colorectal Cancer Patients: The RETROX-CRC Retrospective Study

Background: oxaliplatin with fluoropyrimidine is a “mainstay” regarding the upfront treatment of metastatic colorectal cancer (mCRC). In contrast, the efficacy and safety of oxaliplatin-based regimens in late-care settings have been poorly reported. Methods: we identified a real-world mCRC patient cohort who were re-treated with oxaliplatin, and in which clinicopathological features were retrospectively analyzed to identify efficacy–predictive determinants (RETROX-CRC study). Results: of 2606 patients, 119 fulfilled the eligibility criteria. Oxaliplatin retreatment response rate (RR) and disease control rate (DCR) were 21.6% (CI 14.4–31.0%), and 57.8% (CI 47.7–67.4). A trend towards better RR and DCR was observed among patients who had first oxaliplatin in an adjuvant setting; a poorer outcome was observed if two or more intervening treatments were delivered. Median progression-free survival (PFS) was 5.1 months (95%CI 4.3–6.1), reducing to 4.0 months (95%CI 3.07–5.13) if oxaliplatin was readministered beyond third-line (HR 2.02; 1.25–3.25; p = 0.004). Safety data were retrieved in 65 patients (54.6%); 18.5% (12/65) and 7.7% (5/65) had G3–4 toxicities. Toxicities led to discontinuation in 34/119 (28.6%). Conclusions: oxaliplatin retreatment produced further RR in around one-fifth of patients and DCR 57.8%. Efficacy decreased in more pre-treated patients and around one-third of patients discontinued treatment due to adverse events. Translational studies improving patient selection are warranted.

Hyaluronic Acid-Zein Core-Shell Nanoparticles Improve the Anticancer Effect of Curcumin Alone or in Combination with Oxaliplatin against Colorectal Cancer via CD44-Mediated Cellular Uptake

Curcumin (CUR) has been reported to enhance the chemotherapeutic efficacy of oxaliplatin (OXA) in colorectal cancer (CRC) and inhibit OXA-induced side effects. However, shortcomings, including poor solubility and sensitivity to metabolic transformation, have greatly undermined its value in clinical applications. In this study, the potential of CUR-encapsulated hyaluronic acid (HA)–zein composite nanoparticles (HZ-CUR) as an oral adjuvant for OXA-based chemotherapy was assessed in representative CRC models in mice. Cell viability and colony formation assays in three human CRC cell lines showed that HZ-CUR had a stronger anti-CRC effect than free CUR when given alone and a stronger synergistic effect when combined with OXA, especially in HCT116 and HT29 cell lines. Western blotting, cellular uptake, and RNA interference assays revealed that OXA-induced upregulation of CD44 likely contributed to enhanced cellular uptake of HZ-CUR and thus the enhanced anticancer effect. The significantly improved anti-CRC effects and potential underlying mechanism of HZ-CUR alone and in combination with OXA were further validated in a subcutaneous xenograft and an in situ CRC model in mice. These findings support that HZ-CUR may be an effective oral adjuvant for OXA-based CRC chemotherapy that would not only improve its efficacy but also help reduce the associated side effects.

Circulating tumor DNA to guide rechallenge with panitumumab in metastatic colorectal cancer: the phase 2 CHRONOS trial

Anti-epidermal growth factor receptor (EGFR) monoclonal antibodies are approved for the treatment of RAS wild-type (WT) metastatic colorectal cancer (mCRC), but the emergence of resistance mutations restricts their efficacy. We previously showed that RAS, BRAF and EGFR mutant alleles, which appear in circulating tumor DNA (ctDNA) during EGFR blockade, decline upon therapy withdrawal. We hypothesized that monitoring resistance mutations in blood could rationally guide subsequent therapy with anti-EGFR antibodies. We report here the results of CHRONOS, an open-label, single-arm phase 2 clinical trial exploiting blood-based identification of RAS/BRAF/EGFR mutations levels to tailor a chemotherapy-free anti-EGFR rechallenge with panitumumab (ClinicalTrials.gov: NCT03227926 ; EudraCT 2016-002597-12). The primary endpoint was objective response rate. Secondary endpoints were progression-free survival, overall survival, safety and tolerability of this strategy. In CHRONOS, patients with tissue-RAS WT tumors after a previous treatment with anti-EGFR-based regimens underwent an interventional ctDNA-based screening. Of 52 patients, 16 (31%) carried at least one mutation conferring resistance to anti-EGFR therapy and were excluded. The primary endpoint of the trial was met; and, of 27 enrolled patients, eight (30%) achieved partial response and 17 (63%) disease control, including two unconfirmed responses. These clinical results favorably compare with standard third-line treatments and show that interventional liquid biopsies can be effectively and safely exploited in a timely manner to guide anti-EGFR rechallenge therapy with panitumumab in patients with mCRC. Further larger and randomized trials are warranted to formally compare panitumumab rechallenge with standard-of-care therapies in this patient setting.

Inhibition of cathepsin K sensitizes oxaliplatin-induced apoptotic cell death by Bax upregulation through OTUB1-mediated p53 stabilization in vitro and in vivo

Cathepsin K is highly expressed in various types of cancers. However, the effect of cathepsin K inhibition in cancer cells is not well characterized. Here, cathepsin K inhibitor (odanacatib; ODN) and knockdown of cathepsin K (siRNA) enhanced oxaliplatin-induced apoptosis in multiple cancer cells through Bax upregulation. Bax knockdown significantly inhibited the combined ODN and oxaliplatin treatment-induced apoptotic cell death. Stabilization of p53 by ODN played a critical role in upregulating Bax expression at the transcriptional level. Casein kinase 2 (CK2)-dependent phosphorylation of OTUB1 at Ser16 played a critical role in ODN- and cathepsin K siRNA-mediated p53 stabilization. Interestingly, ODN-induced p53 and Bax upregulation were modulated by the production of mitochondrial reactive oxygen species (ROS). Mitochondrial ROS scavengers prevented OTUB1-mediated p53 stabilization and Bax upregulation by ODN. These in vitro results were confirmed by in mouse xenograft model, combined treatment with ODN and oxaliplatin significantly reduced tumor size and induced Bax upregulation. Furthermore, human renal clear carcinoma (RCC) tissues revealed a strong correlation between phosphorylation of OTUB1(Ser16) and p53/Bax expression. Our results demonstrate that cathepsin K inhibition enhances oxaliplatin-induced apoptosis by increasing OTUB1 phosphorylation via CK2 activation, thereby promoting p53 stabilization, and hence upregulating Bax.

Phase I Dose-Escalation Trial of an Innovative Chemotherapy Regimen Combining a Fractionated Dose of Irinotecan Plus Bevacizumab, Oxaliplatin, 5-Fluorouracil, and Folinic Acid (bFOLFIRINOX-3) in Chemorefractory Metastatic Colorectal Cancer

Simple Summary

Treatment of non-resectable metastatic colorectal cancer (mCRC) involves chemotherapy based on 5-fluorouracil, oxaliplatin and irinotecan and monoclonal antibodies targeting VEGF or EGFR. After an initial progression, it is usual to change the chemotherapy regimen and targeted therapy, with rather moderate results. Several studies have focused on the interest of using again already used molecules and rechallenge with oxaliplatin and irinotecan bi fractionation (FOLFIRI3) have previously shown efficacy in chemorefractory patients, but desynchronized triplet chemotherapy was never tested. The aim of this study was to evaluate the safety and efficacy of a new regimen so-called: FOLFIRINOX-3 bevacizumab in chemorefractory metastatic colorectal cancer.

Abstract

The care of metastatic colorectal cancers is based on combination chemotherapies including 5-fluorouracil, oxaliplatin, irinotecan, and monoclonal antibodies targeting the epidermal growth factor receptor or vascular endothelial growth factor. The regimen is determined based on the patient’s molecular biology and general condition. Irinotecan bifractionation showed efficacy in chemorefractory patients in a previous study, FOLFIRI-3, but a desynchronized triplet has never been tested. The aim of bFOLFIRINOX-3 is to determine the safety, tolerance, and efficacy of a new regimen (FOLFIRINOX-3 bevacizumab) in chemorefractory patients. The aim of this study was to evaluate the safety and efficacy of FOLFIRINOX-3 bevacizumab in chemorefractory metastatic colorectal cancer (mCRC). A standard phase I, “3 + 3” design study was performed. The standard protocol comprised simplified FOLFOX 4 (folinic acid 400 mg/m²), 5-fluorouracil (a 400 mg/m² bolus followed by 2400 mg/m² for 46 h), oxaliplatin (85 mg/m²) and irinotecan (administered before and after 5-fluorouracil infusion), plus bevacizumab (5 mg/kg). In a “3 + 3” design, three different doses of irinotecan were tested: 60, 70 and 90 mg/m². The primary endpoint was the maximum tolerable dose (MTD) of irinotecan. The secondary endpoints included the objective response (at 8 and 16 weeks) according to the RECIST 1.1 criteria and progression free survival. Thirteen patients were enrolled, and twelve patients were finally evaluated for dose-limiting toxicity (DLT). The dose level defined was 70 mg/m² irinotecan. A total of three DLTs were observed (grade 3 diarrhea): two DLTs at the 90 mg/m² dose level and one at the 70 mg/m² dose level. The most frequently described adverse events were asthenia (93%), diarrhea (77%), nausea (62%) and peripheral sensory neuropathy (46%). The most frequent biological event was thrombopenia (54%). Regarding efficacy, among the 11 evaluable patients, no progression was observed at 8 weeks, and the partial response rate was 18.2%. At 16 weeks, a partial response rate of 27.3% was observed, and five patients had a stable disease. The new regimen of bFOLFIRINOX-3 with irinotecan at 70 mg/m² was well tolerated. In chemorefractory patients, this protocol shows a high response rate.

Retreatment of Irinotecan in Later Lines of Therapy for Metastatic Colorectal Cancer: A Retrospective Study

BACKGROUND

Due to few efficacious options in later lines of therapy in metastatic colorectal cancer (mCRC), there has been considerable interest in the possibility of retreatment with previously administered agents. This study investigated the efficacy and safety of irinotecan retreatment (IRI2) in patients with refractory mCRC.

METHODS

We performed a retrospective analysis of patients with mCRC who were retreated with irinotecan-based regimens. The retreatment regimens with anti-epidermal growth factor receptor therapies were excluded.

RESULTS

A total of 64 patients were included. Patients had a median age of 56 years and were offered mainly in the setting of third- or fourth-line therapy with IRI2. The disease control rate was 78.2% including an objective response of 23.5%. Median progression-free survival and overall survival were 5.5 and 19.3 months, respectively. The most frequent grade 3 or higher toxicities were nausea/vomiting (27.9%) and neutropenia (25%).

CONCLUSION

IRI2 might be a reasonable option for heavily pretreated patients with mCRC who achieved disease control with prior irinotecan therapy.

Response of Osteosarcoma Cell Metabolism to Platinum and Palladium Chelates as Potential New Drugs

This paper reports the first metabolomics study of the impact of new chelates Pt₂Spm and Pd₂Spm (Spm = Spermine) on human osteosarcoma cellular metabolism, compared to the conventional platinum drugs cisplatin and oxaliplatin, in order to investigate the effects of different metal centers and ligands. Nuclear Magnetic Resonance metabolomics was used to identify meaningful metabolite variations in polar cell extracts collected during exposure to each of the four chelates. Cisplatin and oxaliplatin induced similar metabolic fingerprints of changing metabolite levels (affecting many amino acids, organic acids, nucleotides, choline compounds and other compounds), thus suggesting similar mechanisms of action. For these platinum drugs, a consistent uptake of amino acids is noted, along with an increase in nucleotides and derivatives, namely involved in glycosylation pathways. The Spm chelates elicit a markedly distinct metabolic signature, where inverse features are observed particularly for amino acids and nucleotides. Furthermore, Pd₂Spm prompts a weaker response from osteosarcoma cells as compared to its platinum analogue, which is interesting as the palladium chelate exhibits higher cytotoxicity. Putative suggestions are discussed as to the affected cellular pathways and the origins of the distinct responses. This work demonstrates the value of untargeted metabolomics in measuring the response of cancer cells to either conventional or potential new drugs, seeking further understanding (or possible markers) of drug performance at the molecular level.

Biomarker-Guided Anti-Egfr Rechallenge Therapy in Metastatic Colorectal Cancer

Simple Summary

The survival of patients with metastatic colorectal cancer (mCRC) has been improved over the years and now reaches 30–40 months. However, few therapeutic options are available after failure of first- and second-line treatments. In fact, prognosis of chemo-refractory mCRC remains poor. Therefore, new therapeutic strategies are needed. Emerging evidence suggest that retreatment with epidermal growth factor (EGFR) inhibitors after a treatment break, in patients that obtained a clinical benefit by previous anti-EGFR, could lead to prolonged survival. The rationale beyond this “rechallenge” strategy is that after a “treatment holiday” EGFR resistant cancer cells decay, restoring the sensibility to EGFR blockade. In this review we analyze the current knowledge of retreatment with EGFR inhibitors, examine the role of novel biomarkers that can guide the appropriate selection of patients. Finally, we discuss future perspectives and on-going clinical trials.

Abstract

The prognosis of patients with metastatic colorectal cancer (mCRC) who progressed to the first and the second lines of treatment is poor. Thus, new therapeutic strategies are needed. During the last years, emerging evidence suggests that retreatment with anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (MAbs) in the third line of mCRC patients, that have previously obtained clinical benefit by first-line therapy with anti-EGFR MAbs plus chemotherapy, could lead to prolonged survival. The rationale beyond this “rechallenge” strategy is that, after disease progression to first line EGFR-based therapy, a treatment break from anti-EGFR drugs results in RAS mutant cancer cell decay, restoring the sensitivity of cancer cells to cetuximab and panitumumab. In fact, rechallenge treatment with anti-EGFR drugs has shown promising clinical activity, particularly in patients with plasma RAS and BRAF wild type circulating tumor DNA, as defined by liquid biopsy analysis at baseline treatment. The aim of this review is to analyze the current knowledge on rechallenge and to investigate the role of novel biomarkers that can guide the appropriate selection of patients that could benefit from this therapeutic strategy. Finally, we discuss on-going trials and future perspectives.

A Computational Framework to Identify Biomarkers for Glioma Recurrence and Potential Drugs Targeting Them

Background: Recurrence is still a major obstacle to the successful treatment of gliomas. Understanding the underlying mechanisms of recurrence may help for developing new drugs to combat gliomas recurrence. This study provides a strategy to discover new drugs for recurrent gliomas based on drug perturbation induced gene expression changes. Methods: The RNA-seq data of 511 low grade gliomas primary tumor samples (LGG-P), 18 low grade gliomas recurrent tumor samples (LGG-R), 155 glioblastoma multiforme primary tumor samples (GBM-P), and 13 glioblastoma multiforme recurrent tumor samples (GBM-R) were downloaded from TCGA database. DESeq2, key driver analysis and weighted gene correlation network analysis (WGCNA) were conducted to identify differentially expressed genes (DEGs), key driver genes and coexpression networks between LGG-P vs LGG-R, GBM-P vs GBM-R pairs. Then, the CREEDS database was used to find potential drugs that could reverse the DEGs and key drivers. Results: We identified 75 upregulated and 130 downregulated genes between LGG-P and LGG-R samples, which were mainly enriched in human papillomavirus (HPV) infection, PI3K-Akt signaling pathway, Wnt signaling pathway, and ECM-receptor interaction. A total of 262 key driver genes were obtained with frizzled class receptor 8 (FZD8), guanine nucleotide-binding protein subunit gamma-12 (GNG12), and G protein subunit β2 (GNB2) as the top hub genes. By screening the CREEDS database, we got 4 drugs (Paclitaxel, 6-benzyladenine, Erlotinib, Cidofovir) that could downregulate the expression of up-regulated genes and 5 drugs (Fenofibrate, Oxaliplatin, Bilirubin, Nutlins, Valproic acid) that could upregulate the expression of down-regulated genes. These drugs may have a potential in combating recurrence of gliomas. Conclusion: We proposed a time-saving strategy based on drug perturbation induced gene expression changes to find new drugs that may have a potential to treat recurrent gliomas.

Oxaliplatin rechallenge in metastatic colorectal cancer patients with clinically significant oxaliplatin-induced peripheral neurotoxicity

We investigated whether rechallenge with oxaliplatin (OXA) can worsen the pre-existing oxaliplatin-induced peripheral neurotoxicity (OXAIPN) in metastatic colorectal cancer (mCRC) patients. Patients previously treated with OXA, having clinically significant grade 1 or 2 OXAIPN were assessed, after receiving rechallenge with OXA, using the clinical version of the Total Neuropathy Score (TNSc). Peripheral neuropathy was assessed at the end of first OXA exposure and at completion of OXA rechallenge. The first line OXA-based chemotherapy was completed at least 9 months earlier (OXA-free interval). We studied 25 mCRC patients, 14 males and 11 females, with a median age of 63 (35-77) years. After their first exposure to OXA-based chemotherapy, 9 (36%) patients developed grade 1 OXAIPN and 16 patients grade 2 (64%) neurotoxicity. OXA reintroduction with a median of 10 (8-14) cycles led to grade 1 OXAIPN in two patients (8%), grade 2 in 19 patients (76%), and grade 3 neuropathy in 4 (16%) patients Worsening of pre-existing OXAIPN was documented in seven (28%) patients and was significantly associated with higher OXA delivered cumulative dose (P < .001). Median TNSc scores following treatment (10; range 4-18) were significantly increased (P < .001), when compared to the scores recorded at the end of first line treatment (8; range 2-12). Rechallenging OXA appears to relatively worsen the severity of existing OXAIPN. However, the majority of rechallenged patients developed a clinically significant (grade 2) OXAIPN, rather than treatment-emergent grade 3. As such, OXA rechallenge might be a feasible option in patients previously having OXAIPN.