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

BACKGROUND

Oxaliplatin represents a main component of cytotoxic treatment regimens in colorectal cancer (CRC). Given its efficacy, oxaliplatin is frequently re-administered in the context of the continuum of care in metastatic CRC (mCRC). However, efficacy and tolerability of this therapeutic strategy has not been comprehensively assessed.

METHODS

We performed a systematic review of the literature on September 19th 2020, according to PRISMA criteria 2009. The research was performed on PubMed, ASCO Meeting Library, ESMO library and ClinicalTrials.gov for citations or ongoing trials.

RESULTS

64 records were retrieved and 13 included in the systematic review: 8 full-text articles, 4 abstracts and 1 ongoing clinical trial. According to readministration timing, studies were classified as rechallenge/reintroduction (n = 8) or stop & go/intermittent therapeutic strategies (n = 4). The studies presented wide heterogeneity in terms of efficacy (Response Rate 6-31%; Disease Control Rate 39-79%; median Progression-Free Survival 3.1-7 months). Those patients who received retreatment after prior adjuvant oxaliplatin or exploiting a stop-&-go strategy appeared to achieve better outcomes. However, no formal comparisons on treatment outcomes were feasible. The most frequent grade 3 or higher adverse events were hematologic toxicities (5-27%), peripheral neuropathy (5-14%) and hypersensitivity reactions (5-20%).

CONCLUSIONS

Retreatment with oxaliplatin for mCRC is practiced based on scarce and heterogeneous data indicating efficacy and manageable toxicity. The best strategy to exploit this approach remains to be defined, and the most promising research avenue to improve therapeutic index of oxaliplatin is represented by selection of responder patients whose tumors harbor molecular defects in the DNA damage repair pathway.

Oxaliplatin-Induced Thrombocytopenia: A Case Report and Review of Pathophysiology of Various Speculative Mechanisms

Oxaliplatin is one of the most common anti-neoplastic agents used in the treatment of small bowel adenocarcinoma. Peripheral neuropathy is one of the most common side effects of oxaliplatin. Oxaliplatin-induced thrombocytopenia is an extremely rare side effect and can result from various mechanisms. We present a case of a 66-year-old female who presented to the hospital for the ninth cycle of FOLFOX chemotherapy for her small bowel adenocarcinoma. The patient developed severe thrombocytopenia within 24 hours of administration of oxaliplatin. Physicians need to be aware of the sudden onset of severe thrombocytopenia associated with oxaliplatin use as early diagnosis and prompt treatment can prove lifesaving for these patients.

Minocycline for Symptom Reduction During Oxaliplatin-Based Chemotherapy for Colorectal Cancer: A Phase II Randomized Clinical Trial

CONTEXT

The most debilitating symptoms during oxaliplatin-based chemotherapy in patients with colorectal cancer (CRC) are neuropathy and fatigue. Inflammation has been suggested to contribute to these symptoms, and the anti-inflammatory agent minocycline is safe and readily available.

OBJECTIVES

This proof-of-concept study investigated minocycline's capacity to reduce treatment-related neuropathy and fatigue and its impact on inflammatory markers during chemotherapy in a Phase II randomized, double-blind, placebo-controlled clinical trial.

METHODS

Patients with locally advanced or metastatic CRC who were scheduled for oxaliplatin-based chemotherapy were randomly assigned to receive either minocycline (100 mg twice daily) or placebo over four months from started chemotherapy. Toxicity assessments and blood samples were prospectively collected monthly. The severity of fatigue and numbness/tingling was assessed weekly using the MD Anderson Symptom Inventory. The primary endpoint, area under the curve for numbness/tingling and fatigue over approximately four months, was compared between the two arms.

RESULTS

Of 66 evaluable participants, 32 received minocycline and 34 placebo. There was no observed significant symptom reduction on both fatigue and numbness/tingling in either arm, nor was there a difference in levels of serum proinflammatory and anti-inflammatory markers between arms. No Grade 3 adverse events nor disparity mediating effects on intervention were observed.

CONCLUSION

Minocycline treatment is feasible and has a low-toxicity profile. However, with 200 mg/day, it did not reduce numbness/tingling or fatigue nor moderate inflammatory biomarkers from this Phase II randomized study. Our results do not support further exploration of minocycline for fatigue or neuropathy symptom intervention in patients treated for CRC.

L-Carnosine protects against Oxaliplatin-induced peripheral neuropathy in colorectal cancer patients: A perspective on targeting Nrf-2 and NF-κB pathways

BACKGROUND

Chemotherapy-induced peripheral neuropathy is a common side effect afflicting cancer patients treated with oxalipatin based chemotherapy.

AIM

The study investigated the potential prophylactic effect of L-carnosine against acute oxaliplatin neurotoxicity in colorectal cancer patients with emphasis on the redox (Nrf-2, MDA), inflammatory (NF-κB, TNF-α), and apoptotic (caspase-3) parameters.

METHODS

In this pilot study, 65 patients were recruited using a prospective randomized controlled study design and enrolled randomly into two arms; Arm A, 31 patients received FOLFOX-6 regimen (oxaliplatin, 5FU & leucovorin) and Arm B, 34 patients received FOLFOX-6 regimen and daily oral L-carnosine (500 mg) along the treatment period. Patients were followed up for three months, then both arms were analyzed for neuropathy incidence/grade and any additional toxicities according to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI-CTC version 4).

RESULTS

The neuropathy grading evaluation of Arm B vs Arm A revealed that 17 patients (56.7%) vs 11 patients (35.5%) suffered grade 1, one patient (3.3%) vs 19 patients (61.3%) suffered grade 2, while 12 patients (40%) vs one patient (3.2%) were normal. In arm B, the addition of L-carnosine decreased significantly the levels/activity of NF-κB (27%) and TNF-α (36.6%); this anti-inflammatory effect entailed also its anti-oxidative and anti-apoptotic effects, thus MDA level (51.8%) and caspase-3 activity (49%) were also reduced, whereas Nrf-2 was increased (38.7%) as compared to Arm A. In both arms a significant correlation was only evident between TNF-α and the neuropathy grading score (P < .03); the correlation analysis was significantly positive between NF-κB and both Nrf-2 and caspase 3.

CONCLUSION

L-Carnosine exerted a neuroprotective effect against oxaliplatin-induced peripheral neuropathy in colorectal cancer patients by targeting Nrf-2 and NF-κB pathways.

Prechemotherapy Touch Sensation Deficits Predict Oxaliplatin-Induced Neuropathy in Patients with Colorectal Cancer

OBJECTIVE

We examined the emergence of chemotherapy-induced peripheral neuropathy (CIPN), a dose-limiting toxicity of oxaliplatin, over the course of oxaliplatin-based chemotherapy for colorectal cancer (CRC). Predicting which patients will likely develop CIPN is an ongoing clinical challenge.

METHODS

Oxaliplatin-naïve patients with CRC underwent quantitative sensory testing (QST) before beginning oxaliplatin-based chemotherapy and then rated CIPN-related symptoms via the MD Anderson Symptom Inventory (MDASI) weekly for 26 weeks. Mixed modeling examined the value of QST for predicting higher CIPN (MDASI numbness/tingling) during treatment. Trajectory analysis identified a patient subgroup with consistently higher CIPN symptoms.

RESULTS

Numbness/tingling was the most frequent, most severe symptom, with 51% of patients clustering into a high CIPN subgroup. Touch sensation deficits (Bumps Detection test) significantly predicted the development of more severe numbness/tingling [estimate (est) = 0.106, p = 0.0003]. The high CIPN subgroup reported increased pain (est = 0.472, p < 0.0001) and interference with walking (est = 0.840, p < 0.0001). In the high CIPN subgroup, patient-reported numbness/tingling worsened rapidly in weeks 0-5 (est = 0.57, p < 0.0001) and then more gradually in weeks 6-26 (est = 0.07, p < 0.0001).

CONCLUSION

Prechemotherapy screening with a simple, easily administered objective measure of touch sensation deficits (Bumps Detection test) and monitoring of patient-reported numbness/tingling during the first 2-3 chemotherapy cycles may support improved personalized care of CRC patients with oxaliplatin-induced CIPN.

2-Deoxyglucose conjugated platinum (II) complexes for targeted therapy: design, synthesis, and antitumor activity

Malignant neoplasms exhibit an elevated rate of glycolysis over normal cells. To target the Warburg effect, we designed a new series of 2-deoxyglucose (2-DG) conjugated platinum (II) complexes for glucose transporter 1 (GLUT1)-mediated anticancer drug delivery. The potential GLUT1 transportability of the complexes was investigated through a comparative molecular docking analysis utilizing the latest GLUT1 protein crystal structure. The key binding site for 2-DG as GLUT1's substrate was identified with molecular dynamics simulation, and the docking study demonstrated that the 2-DG conjugated platinum (II) complexes can be recognized by the same binding site as potential GLUT1 substrate. The conjugates were synthesized and evaluated for in vitro cytotoxicity study with seven human cancer cell lines. The results of this study revealed that 2-DG conjugated platinum (II) complexes are GLUT1 transportable substrates and exhibit improved cytotoxicities in cancer cell lines that over express GLUT1 when compared to the clinical drug, Oxaliplatin. The correlation between GLUT1 expression and antitumor effects are also confirmed. The study provides fundamental information supporting the potential of the 2-DG conjugated platinum (II) complexes as lead compounds for further pharmaceutical R&D.

Repetitive Acupuncture Point Treatment with Diluted Bee Venom Relieves Mechanical Allodynia and Restores Intraepidermal Nerve Fiber Loss in Oxaliplatin-Induced Neuropathic Mice

The chemotherapeutic agent, oxaliplatin, produces a robust painful neuropathy that results in the loss of intraepidermal nerve fibers (IENFs). We have previously reported that an acupuncture point (acupoint) injection of diluted bee venom (DBV) produces a temporary antiallodynic effect in oxaliplatin-induced neuropathic mice. Herein we show a significant long-lasting antinociceptive effect of repetitive DBV acupoint treatment on oxaliplatin-induced mechanical allodynia and a significant reduction in the loss of IENFs. DBV (0.1 mg/kg, subcutaneous) was administered once a day for 18 days beginning on day 15 after oxaliplatin injection. Immunohistochemistry for IENF was performed on the glabrous skin of the hind paw footpad using the pan-neuronal marker, protein gene product 9.5. A temporary increase in mechanical threshold was observed 60 minutes after a single DBV injection into the Zusanli acupoint, and this effect was enhanced over time with repetitive DBV treatments. The basal mechanical threshold before daily DBV injection also increased from day 7 after DBV injections, and peaked at day 14 after DBV treatment. Moreover, the oxaliplatin-induced loss of IENFs was significantly reduced in mice treated repetitively with DBV. Repetitive pretreatment with the α-2 adrenoceptor antagonist, yohimbine, (5 mg/kg, subcutaneous) completely prevented the antiallodynic effects and the increase in IENFs observed in mice treated repetitively with DBV.

PERSPECTIVE

We showed that repetitive acupoint stimulation with DBV gradually and significantly reduced oxaliplatin-induced mechanical allodynia and restored the loss of IENFs in neuropathic mice via an α-2 adrenoceptor mechanism. Collectively, results of this study suggest that repetitive acupoint treatment with DBV can be a potential strategy for the management of chemotherapy-induced neuropathy.

Autophagy contributes to the enrichment and survival of colorectal cancer stem cells under oxaliplatin treatment

Currently, chemoresistance is an important cause of treatment failure in colorectal cancer. Cancer stem cells, which are a population of multi-potent cells with the capacity to self-renew and differentiate, have been found to participate in chemoresistance. In the present study, the chemotherapeutic drug oxaliplatin induced autophagy in colorectal cancer cell lines, which in turn protected cancer cells from apoptosis. Further results showed that oxaliplatin-induced autophagy enriched the population of colorectal CSCs and participated in maintaining the stemness of colorectal CSCs, thus making the cells more resistant to chemotherapy. Taken together, the results indicate that autophagy might enhance the chemoresistance of colorectal cancer cells by protecting the stemness and chemoresistance of colorectal CSCs. Our study demonstrates that autophagy plays a pro-survival role in colorectal CSCs subjected to oxaliplatin. Therefore, targeting autophagy may be considered as a potential therapeutic strategy to address chemoresistance in the treatment of colorectal cancer.

Chemotherapy-induced peripheral neurotoxicity: a critical analysis

With a 3-fold increase in the number of cancer survivors noted since the 1970s, there are now over 28 million cancer survivors worldwide. Accordingly, there is a heightened awareness of long-term toxicities and the impact on quality of life following treatment in cancer survivors. This review will address the increasing importance and challenge of chemotherapy-induced neurotoxicity, with a focus on neuropathy associated with the treatment of breast cancer, colorectal cancer, testicular cancer, and hematological cancers. An overview of the diagnosis, symptomatology, and pathophysiology of chemotherapy-induced peripheral neuropathy will be provided, with a critical analysis of assessment strategies, neuroprotective approaches, and potential treatments. The review will concentrate on neuropathy associated with taxanes, platinum compounds, vinca alkaloids, thalidomide, and bortezomib, providing clinical information specific to these chemotherapies.

Drug rechallenge and treatment beyond progression--implications for drug resistance

The established dogma in oncology for managing recurrent or refractory disease dictates that therapy is changed at disease progression, because the cancer is assumed to have become drug-resistant. Drug resistance, whether pre-existing or acquired, is largely thought to be a stable and heritable process; thus, reuse of therapeutic agents that have failed is generally contraindicated. Over the past few decades, clinical evidence has suggested a role for unstable, non-heritable mechanisms of acquired drug resistance pertaining to chemotherapy and targeted agents. There are many examples of circumstances where patients respond to reintroduction of the same therapy (drug rechallenge) after a drug holiday following disease relapse or progression during therapy. Additional, albeit limited, evidence suggests that, in certain circumstances, continuing a therapy beyond disease progression can also have antitumour activity. In this Review, we describe the anticancer agents used in these treatment strategies and discuss the potential mechanisms explaining the apparent tumour re-sensitization with reintroduced or continued therapy. The extensive number of malignancies and drugs that challenge the custom of permanently switching to different drugs at each line of therapy warrants a more in-depth examination of the definitions of disease progression and drug resistance and the resulting implications for patient care.

Diluted bee venom injection reduces ipsilateral mechanical allodynia in oxaliplatin-induced neuropathic mice

Oxaliplatin, which is used as one of anti-cancer drugs, commonly induces peripheral neuropathic pain. We have previously reported that an injection of diluted bee venom (DBV) produced a significant anti-nociceptive effects in several pain models of mice or rats. In this study, we evaluated time- and dose-dependent development of oxaliplatin-induced mechanical allodynia in bilateral hind paws of mice, and investigated the effect of DBV injection on this mechanical allodynia. DBV (0.1 mg/kg) was subcutaneously injected into the Zusanli acupoint 2 weeks after oxaliplatin (10 mg/kg) injection. One hour after DBV injection, we observed a significant reduction of mechanical allodynia in the ipsilateral hind paw, but not in the contralateral hind paw to DBV injection site. We subsequently examined whether this effect of DBV was related to the activation of peripheral nerves in DBV injected site, and then whether it was mediated by the activation of spinal cord alpha-2 adrenoceptors or opioid receptors. Subcutaneous pre-injection of 2% lidocaine (40 mg/kg) into the Zusanli acupoint completely blocked the anti-allodynic effect of DBV. Intrathecal pretreatment with yohimbine (25 µg/mouse), an alpha-2 adrenoceptor antagonist, also prevented the anti-allodynic effect of DBV, whereas pretreatment with naloxone (20 µg/mouse), an opioid receptor antagonist, did not block the effect of DBV. Taken together, these findings demonstrate that DBV injection into the Zusanli acupoint significantly reduces ipsilateral mechanical allodynia generated by oxaliplatin in mice, and also suggest that this anti-allodynic effect is dependent on the peripheral nerve activation in injected site and spinal cord alpha-2 adrenoceptors.

Spinal astrocyte gap junctions contribute to oxaliplatin-induced mechanical hypersensitivity

Spinal glial cells contribute to the development of many types of inflammatory and neuropathic pain. Here the contribution of spinal astrocytes and astrocyte gap junctions to oxaliplatin-induced mechanical hypersensitivity was explored. The expression of glial fibrillary acidic protein (GFAP) in spinal dorsal horn was significantly increased at day 7 but recovered at day 14 after oxaliplatin treatment, suggesting a transient activation of spinal astrocytes by chemotherapy. Astrocyte-specific gap junction protein connexin 43 (Cx43) was significantly increased in dorsal horn at both day 7 and day 14 following chemotherapy, but neuronal (connexin 36 [Cx36]) and oligodendrocyte (connexin 32 [Cx32]) gap junction proteins did not show any change. Blockade of astrocyte gap junction with carbenoxolone (CBX) prevented oxaliplatin-induced mechanical hypersensitivity in a dose-dependent manner and the increase of spinal GFAP expression, but had no effect once the mechanical hypersensitivity induced by oxaliplatin had fully developed. These results suggest that oxaliplatin chemotherapy induces the activation of spinal astrocytes and this is accompanied by increased expression of astrocyte-astrocyte gap junction connections via Cx43. These alterations in spinal astrocytes appear to contribute to the induction but not the maintenance of oxaliplatin-induced mechanical hypersensitivity. Combined, these results suggest that targeting spinal astrocyte/astrocyte-specific gap junction could be a new therapeutic strategy to prevent oxaliplatin-induced neuropathy.

PERSPECTIVE

Spinal astrocytes but not microglia were recently shown to be recruited in paclitaxel-related chemoneuropathy. Here, spinal astrocyte gap junctions are shown to play an important role in the induction of oxaliplatin neuropathy.

HOCl oxidation-modified CT26 cell vaccine inhibits colon tumor growth in a mouse model

Despite progress in elucidating mechanisms associated with colorectal cancer and improvement of treatment methods, it remains a frequent cause of death worldwide. New and more effective therapies are therefore urgently needed. Recent studies have shown that immunogenicity of whole ovarian tumor cells and subsequent T cell response were potentiated by oxidation modification with hypochlorous acid (HOCl) in vitro and ex vivo. These results prompted us to investigate the protective antitumor response with an HOCl treated CT26 colorectal cancer cell vaccine in an in vivo mouse model. Administration of HOCl modified vaccine triggered robust antitumor immunity to autologous tumor cells in mice and prolonged survival period significantly. In addition, increased necrosis and apoptosis were found in tumor tissue from the oxidation group. Interestingly, ELISPOT assays showed that specific T cell responses were not elicited in response to the immunizing cellular antigen, in contrast to raising sera antibody titer and antibody binding activity shown by ELISA assay and flow cytometry. Further evaluation of the mechanisms underlying HOCl modified vaccine mediated humoral immunity highlighted the role of antibody-dependent cell-mediated cytotoxicity. These results combined with previous studies suggest that HOCl oxidation modified whole cell vaccine has wide applicability as a cancer vaccine because it can target both T cell- and B cell-specific responses. It may thus represent a promising approach for the immunotherapy of colorectal cancer.

Autophagy protects against oxaliplatin-induced cell death via ER stress and ROS in Caco-2 cells

Oxaliplatin is included in a number of effective combination regimens used as first and subsequent lines of therapy for metastatic colorectal cancer. Accumulating evidence indicates that autophagy plays a significant role in response to cancer therapy. However, the role of autophagy in oxaliplatin-induced cell death remains to be clarified. In this study, we showed that oxaliplatin induced cell death and autophagy in Caco-2 colorectal cancer cells. The suppression of autophagy using either pharmacologic inhibitors (3-methyladenine, bafilomycin A1) or RNA interference in essential autophagy genes (ATG5 or Beclin1) enhanced the cell death and reactive oxygen species (ROS) production induced by oxaliplatin in Caco-2 cells. Blocking oxaliplatin-induced ROS production by using ROS scavengers (NAC or Tiron) decreased autophagy. Furthermore, numerous dilated endoplasmic reticula (ER) were present in oxaliplatin-treated Caco-2 cells, and blocking ER stress by RNA interference against candidate of metastasis-1 (P8) and C/EBP-homologous protein (CHOP) decreased autophagy and ROS production. Taken together, these data indicate that oxaliplatin activates autophagy as a cytoprotective response via ER stress and ROS in human colorectal cancer cells.

Overview of biomarkers in metastatic colorectal cancer: tumour, blood and patient-related factors

During the last 20 years there have been major therapeutic developments in colorectal cancer (CRC) with the introduction of multiple novel therapeutic agents into routine clinical practice. This has improved survival in both the adjuvant and advanced disease settings. However, improvements have come with substantial increases in expense to the community and potential toxicity to the patient. There has been substantial research to identify tumour factors in CRC that predict treatment response and survival outcomes. This research has identified clinically useful predictive biomarkers to aid clinical decision making, such as the presence or absence of KRAS gene mutations which can determine the benefit of using epidermal growth factor receptor (EGFR) inhibiting antibodies. However, less attention has been paid to the identification and impact of predictive patient-derived factors such as age, gender and the presence of comorbid conditions or evidence of a systemic inflammatory response. In this article, the current concepts of tumour and patient-related predictive factors in CRC management are reviewed.