Risk of Cardiovascular Complications Among Type 2 Diabetes Mellitus Patients with GSTP1 Genetic Polymorphism: A Nested Case-Control Study and Docking Studies

The genetic alteration in the antioxidant gene Glutathione-S-Transferases Pi 1 (GSTP1) namely GSTP1*IIe105Val (rs1695) and GSTP1*Ala114Val (rs1138272) changes the individual susceptibility to cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM) by altering the substrate binding and catalytic activity. This study aims to investigate the association of GSTP1 rs1695 and rs1138272 polymorphism with CVD development in T2DM patients. Genotyping was performed with 400 study participants-group I: control; group II: T2DM; group III: CVD; and group IV: T2DM/CVD [n = 100 each] by PCR-RFLP. The rs1695 and rs1138272 polymorphism were docked against NPACT and NUBBE database and virtually screened using glide. The study reported that rs1695 polymorphism was associated with T2DM risk under dominant and allelic genetic models [OR = 1.97(1.08-3.59) p = 0.02 and OR = 1.79(1.20-2.66) p = 0.003, respectively]. The val/val genotype, dominant, recessive model, and T allelic genetic model were associated with increased CVD risk [OR = 4.15(1.97-8.73) p =  < 0.01; OR = 3.16(1.65-6.04) p =  < 0.01; OR = 3.47(1.91-6.31) p =  < 0.01; and OR = 2.94(1.95-4.43) p =  < 0.01, respectively]. In contrast, rs1695 polymorphism was not associated with CVD development among patients with T2DM. In rs1138272, the wild genotype was only detected and neither heterozygous nor val/val genotype was observed. The docking analysis revealed that the Ile105Val mutation plays a significant role in altering the GSTP1 capacity compared to the Ala115Val mutation. This suggests that the Ile105Val mutation has a greater impact on the protein's structure, function, or susceptibility to diseases compared to the Ala115Val mutation. In summary, genetic alteration in GSTP1 rs1695 potentially contributes to an increased risk of T2DM and CVD.

Neuroprotective Effect of Natural Compounds in Paclitaxel-Induced Chronic Inflammatory Pain

The current study explored the effects of natural compounds, berbamine, bergapten, and carveol on paclitaxel-associated neuroinflammatory pain. Berbamine, an alkaloid obtained from BerberisamurensisRuprhas been previously researched for anticancer and anti-inflammatory potential. Bergapten is 5-methoxsalenpsoralen previously investigated in cancer, vitiligo, and psoriasis. Carveol obtained from caraway is a component of essential oil. The neuropathic pain model was induced by administering 2 mg/kg of paclitaxel (PTX) every other day for a week. After the final PTX injection, a behavioral analysis was conducted, and subsequently, tissue was collected for molecular analysis. Berbamine, bergapten, and carveol treatment attenuated thermal hypersensitivity, improved latency of falling, normalized the changes in body weight, and increased the threshold for pain sensation. The drugs increased the protective glutathione (GSH) and glutathione S-transferase (GST) levels in the sciatic nerve and spinal cord while lowering inducible nitric oxide synthase (iNOS) and lipid peroxidase (LPO). Hematoxylin and eosin (H and E) and immunohistochemistry (IHC) examinations confirmed that the medication reversed the abnormal alterations. The aforementioned natural substances inhibited cyclooxygenase-2 (COX-2), tumor necrosis factor-alpha (TNF-α), and nuclear factor kappa B (NF-κb) overexpression, as evidenced by enzyme-linked immunosorbant assay (ELISA) and Western blot and hence provide neuroprotection in chronic constriction damage.

A novel docetaxel derivative exhibiting potent anti-tumor activity and high safety in preclinical animal models

As a taxoid agent, docetaxel (DTX) exhibits potent antitumor activity. However, severe toxic side effects and acquired multidrug resistance represent its clinical challenges. Herein, a novel docetaxel derivative (DTX-AI) is synthesized via the nucleophilic addition reaction of 4-acetylphenyl carbamate at the C10 position of the DTX framework. DTX-AI exhibits superior cytotoxicity and a higher apoptotic ratio in vitro against DTX-sensitive tumor cells (MCF-7, HeLa and A549 cells) and even DTX-resistant ones (HeLa/PTX cells), but displays less toxicity against normal cells (MRC-5 and L929 cells) compared with DTX. DTX-AI can effectively suppress the growth of HeLa-tumor xenografts in vivo and even induce complete tumor regression. Furthermore, DTX-AI shows sustained effects on the inhibition of A549-tumor xenograft growth and no obvious recurrence, even after the drug administration was stopped for 30 d. More importantly, DTX-AI has significantly reduced long-term and short-term animal toxicity and extended the survival of mice (100%) compared with DTX (0%). DTX-AI is expected to be a promising 'me-better' anti-tumor drug with higher efficiency and lower toxicity for improved chemotherapy in the clinic.

Single-nucleotide polymorphisms and the effectiveness of taxane-based chemotherapy in premenopausal breast cancer: a population-based cohort study in Denmark

Purpose

Taxane-based chemotherapy is the primary treatment for premenopausal breast cancer. Although being inconsistent, research suggests that variant alleles alter pharmacokinetics through reduced function of OATP transporters (limiting hepatic uptake), CYP-450 enzymes (hampering drug metabolism), and ABC transporters (decreasing clearance). Reduced function of DNA repair enzymes may hamper effectiveness through dose-limiting toxicities. We investigated whether single-nucleotide polymorphisms (SNPs) were associated with breast cancer recurrence or mortality in premenopausal women diagnosed with breast cancer.

Methods

We conducted a population-based cohort study of premenopausal women diagnosed with non-distant metastatic breast cancer in Denmark during 2007‒2011, when guidelines recommended adjuvant combination chemotherapy (taxanes, anthracyclines, and cyclophosphamide). Using archived formalin-fixed paraffin-embedded primary tumor tissue, we genotyped 26 SNPs using TaqMan assays. Danish health registries provided data on breast cancer recurrence (through September 25, 2017) and death (through December 31, 2019). We fit Cox regression models to calculate crude hazard ratios (HRs) and 95% confidence intervals (CIs) for recurrence and mortality across genotypes.

Results

Among 2,262 women, 249 experienced recurrence (cumulative incidence: 13%) and 259 died (cumulative incidence: 16%) during follow-up (median 7.0 and 10.1 years, respectively). Mortality was increased in variant carriers of GSTP1 rs1138272 (HR: 1.30, 95% CI 0.95–1.78) and CYP3A rs10273424 (HR: 1.33, 95% CI 0.98–1.81). SLCO1B1 rs2306283 (encoding OATP1B1) variant carriers had decreased recurrence (HR: 0.82, 95% CI 0.64–1.07) and mortality (HR: 0.77, 95% CI 0.60–0.98).

Conclusion

Docetaxel effectiveness was influenced by SNPs in GSTP1, CYP3A, and SLCO1B1 in premenopausal women with non-distant metastatic breast cancer, likely related to altered docetaxel pharmacokinetics. These SNPs may help determine individual benefit from taxane-based chemotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10549-022-06596-2.

Association between Genetic Polymorphism of GSTP1 and Toxicities in Patients Receiving Platinum-Based Chemotherapy: A Systematic Review and Meta-Analysis

Platinum-based chemotherapy regimens have been proven to be effective in various cancers; however, considerable toxicities may develop and can even lead to treatment discontinuation. Diverse factors may influence adverse treatment events, with pharmacogenetic variations being one prime example. Polymorphisms within the glutathione S-transferase pi 1 (GSTP1) gene may especially alter enzyme activity and, consequently, various toxicities in patients receiving platinum-based chemotherapy. Due to a lack of consistency in the degree of elevated complication risk, we performed a systematic literature review and meta-analysis to determine the level of platinum-associated toxicity in patients with the GSTP1 rs1695 polymorphism. We conducted a systematic search for eligible studies published before January 2022 from PubMed, Web of Science, and EMBASE based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to evaluate the strength of the association between the rs1695 polymorphism and various toxicities. Ten eligible studies met the inclusion criteria. The pooled ORs for hematological toxicity and neutropenia in the patients with the variant (G) allele were 1.7- and 2.6-times higher than those with the AA genotype (95% CI 1.06–2.73 and 1.07–6.35), respectively. In contrast, the rs1695 polymorphism resulted in a 44% reduced gastrointestinal toxicity compared to wild-type homozygotes. Our study found that the GSTP1 rs1695 polymorphism was significantly correlated with platinum-induced toxicities. The study also revealed that rs1695 expression exhibited tissue-specific patterns and thus yielded opposite effects in different tissues. A personalized chemotherapy treatment based on these polymorphisms may be considered for cancer patients in the future.

Tolerability of Eribulin and correlation between polymorphisms and neuropathy in an unselected population of female patients with metastatic breast cancer: results of the multicenter, single arm, phase IV PAINTER study

BACKGROUND

Metastatic breast cancer (MBC) is an incurable disease and its treatment focuses on prolonging patients' (pts) overall survival (OS) and improving their quality of life. Eribulin is a microtubule inhibitor that increases OS in pre-treated MBC pts. The most common adverse events (AEs) are asthenia, neutropenia and peripheral neuropathy (PN).

METHODS

PAINTER is a single arm, phase IV study, aimed at evaluating the tolerability of eribulin in MBC pts. Secondary objectives were the description of treatment efficacy and safety, the assessment of the incidence and severity of PN and its association with genetic polymorphisms. Genomic DNA was isolated from blood samples and 15 Single Nucleotide Polymorphisms (SNPs) were genotyped by Taqman specific assays. The association between PN and SNPs were evaluated by Fisher exact test.

RESULTS

Starting from May 2014 until June 2018 180 pts were enrolled in this study by 20 Italian centers. 170 of these pts could be evaluated for efficacy and toxicity and 159 for polymorphisms analysis. The median age of pts was 60 years old and the biological subtypes were luminal type (64.7%), Her2 positive (18.3%) and triple negative (17%). Pts were pretreated with a median of 5 lines for MBC. The median follow up of this study was 15.4 months with a median number of 4.5 cycles administered (minimum-maximum 1-23). The median overall survival was 12 months. 48.8% of pts experienced a dose reduction, mainly for neutropenia (23.9%) and liver toxicity (12%). 65 pts (38.2%) reported at least one severe toxicity. Neutropenia and neurotoxicity were the most frequent severe AEs (15.3% and 14.7%, respectively); other reported toxicities were osteo-muscular, abdominal or tumor site pain (19.4%), liver toxicity (6.6%), pulmonary toxicity (6.5%) and dermatological toxicity (3.6%). Among the 15 evaluated SNPs, an association with PN was found for rs2233335 and rs7214723.

CONCLUSIONS

Eribulin is a well-tolerated treatment option in MBC. Schedule and dosage modifications were common, but toxicity rarely led to treatment discontinuation. SNPs rs2233335 (G/T and T/T) in the NDRG1 gene and rs7214723 (CC and CT) in the CAMKK1 gene were associated with PN. These findings, if validated, could allow a tailored treatment with eribulin in cancer patients.

TRIAL REGISTRATION

ClinicalTrials.gov ID: NCT02864030.

Management of Side Effects in the Personalized Medicine Era: Chemotherapy-Induced Peripheral Neurotoxicity

Pharmacogenomics is a powerful tool to predict individual response to treatment, in order to personalize therapy, and it has been explored extensively in oncology practice. Not only efficacy on the malignant disease has been investigated but also the possibility to predict adverse effects due to drug administration. Chemotherapy-induced peripheral neurotoxicity (CIPN) is one of those. This potentially severe and long-lasting/permanent side effect of commonly administered anticancer drugs can severely impair quality of life (QoL) in a large cohort of long survival patients. So far, a pharmacogenomics-based approach in CIPN regard has been quite delusive, making a methodological improvement warranted in this field of interest: even the most refined genetic analysis cannot be effective if not applied correctly. Here we try to devise why it is so, suggesting how THE "bench-side" (pharmacogenomics) might benefit from and should cooperate with THE "bed-side" (clinimetrics), in order to make genetic profiling effective if applied to CIPN.

DNA-PKc inhibition overcomes taxane resistance by promoting taxane-induced DNA damage in prostate cancer cells

BACKGROUND

Overcoming taxane resistance remains a major clinical challenge in metastatic castrate-resistant prostate cancer (mCRPC). Loss of DNA repair proteins is associated with resistance to anti-microtubule agents. We propose that alterations in DNA damage response (DDR) pathway contribute to taxane resistance, and identification of these alterations may provide a potential therapeutic target to resensitize docetaxel-refractory mCRPC to taxane-based therapy.

METHODS

Alterations in DDR gene expression in our prostate cancer cell line model of docetaxel-resistance (DU145-DxR) derived from DU-145 cells were determined by DDR pathway-specific polymerase chain reaction array and immunoblotting. The PRKDC gene encoding DNA-PKc (DNA-dependent protein kinase catalytic unit), was noted to be overexpressed and evaluated for its role in docetaxel resistance. Cell viability and clonogenic survival of docetaxel-treated DU145-DxR cells were assessed after pharmacologic inhibition of DNA-PKc with three different inhibitors-NU7441, LTURM34, and M3814. Response to second-line cytotoxic agents, cabazitaxel and etoposide upon DNA-PKc inhibition was also tested. The impact of DNA-PKc upregulation on DNA damage repair was evaluated by comet assay and analysis of double-strand breaks marker, γH2AX and Rad51. Lastly, DNA-PKc inhibitor's effect on MDR1 activity was assessed by rhodamine 123 efflux assay.

RESULTS

DDR pathway-specific gene profiling revealed significant upregulation of PRKDC and CDK7, and downregulation of MSH3 in DU145-DxR cells. Compared to parental DU145, DU145-DxR cells sustained significantly less DNA damage when exposed to etoposide and docetaxel. Pharmacologic inhibition of DNA-PKc, a component of NHEJ repair machinery, with all three inhibitors, significantly resensitized DU145-DxR cells to docetaxel. Furthermore, DNA-PKc inhibition also resensitized DU145-DxR to cabazitaxel and etoposide, which demonstrated cross-resistance. Inhibition of DNA-PKc led to increased DNA damage in etoposide- and docetaxel-treated DU145-DxR cells. Finally, DNA-PKc inhibition did not affect MDR1 activity, indicating that DNA-PKc inhibitors resensitized taxane-resistant cells via an MDR1-independent mechanism.

CONCLUSION

This study supports a role of DDR genes, particularly, DNA-PKc in promoting resistance to taxanes in mCRPC. Targeting prostatic DNA-PKc may provide a novel strategy to restore taxane sensitivity in taxane-refractory mCRPC.

An Example of Personalized Treatment in HR+ HER2+ Long Survivor Breast Cancer Patient (Case Report)

Background. Personalized therapy is becoming increasingly popular in oncological scenarios, not only based on molecular pharmacological targets, but also preventing any drug–drug–gene interaction (DDGI), which could lead to severe toxicities. Single nucleotide polymorphisms (SNPs), the individual germline sequence variations in genes involved in drug metabolism, are correlated to interindividual response to drugs and explain both efficacy and toxicity profiles reported by patients. Case presentation. We present the case of a woman suffering from triple-positive breast cancer; she had early-stage disease at the onset and after four years developed metastatic disease. During her history, she presented different toxicities due to antineoplastic treatments. Particularly, hypertransaminasemia was found during every line of treatment. Nevertheless, we were able to guarantee the patient an excellent therapeutic adhesion thanks to the supportive treatments and the reduction of drug dosage. Moreover, we conducted a simultaneous analysis of the patient’s biochemical and genomic data thanks to Drug-PIN software, and we found several significant SNPs of the main enzymes and transporters involved in drug metabolism. Conclusion. Our case report demonstrated the relevance of DDGI in clinical practice management of a patient treated for advanced breast cancer, suggesting the role of Drug-PIN software as an easy-to-use tool to prevent adverse events during cancer treatment and to help physicians in therapeutic algorithms. However, further studies are needed to confirm these results.

Association between Low-Grade Chemotherapy-Induced Peripheral Neuropathy (CINP) and Survival in Patients with Metastatic Adenocarcinoma of the Pancreas

The combination of nab-paclitaxel and gemcitabine demonstrated greater efficacy than gemcitabine alone but resulted in higher rates of chemotherapy-induced peripheral neuropathy (CINP) in patients with metastatic pancreatic cancer (mPC). We aimed to evaluate the correlation between the development of treatment-related peripheral neuropathy and the efficacy of nab-P/Gem combination in these patients. mPC patients treated with nab-paclitaxel 125 mg/m² and gemcitabine 1000 mg/m² as a first-line therapy were included. Treatment-related adverse events, mainly peripheral neuropathy, were categorized using the National Cancer Institute Common Toxicity Criteria scale, version 4.02. Efficacy outcomes, including overall survival (OS), progression-free survival (PSF), and disease control rate (DCR), were estimated by the Kaplan–Meier model. A total of 153 patients were analyzed; of these, 47 patients (30.7%) developed grade 1–2 neuropathy. PFS was 7 months (95% CI (6–7 months)) for patients with grade 1–2 neuropathy and 6 months (95% CI (5–6 months)) for patients without peripheral neuropathy (p = 0.42). Median OS was 13 months (95% CI (10–18 months)) and 10 months (95% CI (8–13 months)) in patients with and without peripheral neuropathy, respectively (p = 0.04). DCR was achieved by 83% of patients with grade 1–2 neuropathy and by 58% of patients without neuropathy (p = 0.03). In the multivariate analysis, grade 1–2 neuropathy was independently associated with OS (HR 0.65; 95% CI, 0.45–0.98; p = 0.03). nab-P/Gem represents an optimal first-line treatment for mPC patients. Among possible treatment-related adverse events, peripheral neuropathy is the most frequent, with different grades and incidence. Our study suggests that patients experiencing CINP may have a more favorable outcome, with a higher disease control rate and prolonged median survival compared to those without neuropathy.

Exploring pharmacogenetics of paclitaxel- and docetaxel-induced peripheral neuropathy by evaluating the direct pharmacogenetic-pharmacokinetic and pharmacokinetic-neuropathy relationships

Introduction: Peripheral neuropathy (PN) is an adverse effect of several classes of chemotherapy including the taxanes. Predictive PN biomarkers could inform individualized taxane treatment to reduce PN and enhance therapeutic outcomes. Pharmacogenetics studies of taxane-induced PN have focused on genes involved in pharmacokinetics, including enzymes and transporters. Contradictory findings from these studies prevent translation of genetic biomarkers into clinical practice. Areas covered: This review discusses the progress toward identifying pharmacogenetic predictors of PN by assessing the evidence for two independent associations; the effect of pharmacogenetics on taxane pharmacokinetics and the evidence that taxane pharmacokinetics affects PN. Assessing these direct relationships allows the reader to understand the progress toward individualized taxane treatment and future research opportunities. Expert opinion: Paclitaxel pharmacokinetics is a major determinant of PN. Additional clinical trials are needed to confirm the clinical benefit of individualized dosing to achieve target paclitaxel exposure. Genetics does not meaningfully contribute to paclitaxel pharmacokinetics and may not be useful to inform dosing. However, genetics may contribute to PN sensitivity and could be useful for estimating patients' optimal paclitaxel exposure. For docetaxel, genetics has not been demonstrated to have a meaningful effect on pharmacokinetics and there is no evidence that pharmacokinetics determines PN.

Predictive value of clinical toxicities of chemotherapy with fluoropyrimidines and oxaliplatin in colorectal cancer by DPYD and GSTP1 gene polymorphisms

BACKGROUND

Fluoropyrimidines and platinum are still widely used for colorectal cancer (CRC) management. Several studies have reported that mutations of dihydropyrimidine dehydrogenase (DPYD) and glutathione S-transferase pi-1 (GSTP1) polymorphisms are related to chemotherapy-related adverse events. In the present study, we purposed to assess the impact of DPYD and GSTP1 variants on the toxicity of adjuvant chemotherapy risk among the Hakka population, minimize adverse events, and to maximize therapy outcome for individualized treatment.

METHODS

Genotyping was examined in 104 patients diagnosed with CRC cases and receiving fluoropyrimidine and platinum drug-based chemotherapy regimen by direct sequencing of DPYD and GSTP1 polymorphisms. Three DPYD variants including *2A, *5A, *9A, and GSTP1 c.313A>G were analyzed and clinical outcomes were assessed.

RESULTS

The data suggest that the incidence of DPYD*5A, DPYD*9A, and GSTP1 c.313A>G variants were 38.4%, 24%, and 32.7%, respectively. DPYD*2A variant was not found. A total of 23 patients (22.1%) suffered severe vomiting and 19 patients (18.3%) suffered severe anemia. DPYD*5A polymorphism was found significantly associated with grade 3/4 ulceration (p = 0.001). GSTP1 was determined to be an independent risk factor for severe vomiting and skin ulceration (p = 0.042 and p = 0.018, respectively). Patients with GSTP1 c. 313A>G mutant type contributed to a higher risk for grade severe toxicity compared with wild genotype (p = 0.027). Nevertheless, no significant difference was found between patients with DPYD*2A, *5A, and *9A for chemotherapeutic toxicity.

CONCLUSIONS

The results demonstrated that GSTP1 polymorphisms were useful predictors of severe events. Screening of single-nucleotide polymorphisms of GSTP1 in colorectal cancer patients before chemotherapy may help to realize personalized therapy.

The Role of Oxidative Stress in Peripheral Neuropathy

Peripheral neuropathy (PN) is a common disease affecting about 5% of the general population after the age of 50. Causes of PN are numerous and include genetic, diabetes, alcohol, vitamin deficiencies, and gluten sensitivity among others. This systematic review aimed to study the association between oxidative stress and PN in an attempt to better understand PN pathogenesis. A computer-based, systematic search was conducted on the PubMed database, and ensuing data from included articles was analyzed and discussed in this review. Sixty-nine papers were eligible and were used for this review. Peripheral neuropathy is associated with an increase of reactive oxygen species and a decrease in endogenous antioxidants. Genetic predisposition to oxidative damage may be a factor. Antioxidant treatment is promising regarding treatment. Though further research is necessary to better understand the underlying mechanism, it is evident that oxidative stress is implicated in the pathogenesis of - or is at least systematically present in - PN.

GSTP1 and cancer: Expression, methylation, polymorphisms and signaling (Review)

Glutathione S‑transferase Pi (GSTP1) is an isozyme encoded by the GST pi gene that plays an important regulatory role in detoxification, anti‑oxidative damage, and the occurrence of various diseases. The aim of the present study was to review the association between the expression of GSTP1 and the development and treatment of various cancers, and discuss GSTP1 methylation in several malignant tumors, such as prostate, breast and lung cancer, as well as hepatocellular carcinoma; to review the association between polymorphism of the GSTP1 gene and various diseases; and to review the effects of GSTP1 on electrophilic oxidative stress, cell signal transduction, and the regulation of carcinogenic factors. Collectively, GSTP1 plays a major role in the development of various diseases.

Pathogenesis of paclitaxel-induced peripheral neuropathy: A current review of in vitro and in vivo findings using rodent and human model systems

Paclitaxel (Brand name Taxol) is widely used in the treatment of common cancers like breast, ovarian and lung cancer. Although highly effective in blocking tumor progression, paclitaxel also causes peripheral neuropathy as a side effect in 60-70% of chemotherapy patients. Recent efforts by numerous labs have aimed at defining the underlying mechanisms of paclitaxel-induced peripheral neuropathy (PIPN). In vitro models using rodent dorsal root ganglion neurons, human induced pluripotent stem cells, and rodent in vivo models have revealed a number of molecular pathways affected by paclitaxel within axons of sensory neurons and within other cell types, such as the immune system and peripheral glia, as well skin. These studies revealed that paclitaxel induces altered calcium signaling, neuropeptide and growth factor release, mitochondrial damage and reactive oxygen species formation, and can activate ion channels that mediate responses to extracellular cues. Recent studies also suggest a role for the matrix-metalloproteinase 13 (MMP-13) in mediating neuropathy. These diverse changes may be secondary to paclitaxel-induced microtubule transport impairment. Human genetic studies, although still limited, also highlight the involvement of cytoskeletal changes in PIPN. Newly identified molecular targets resulting from these studies could provide the basis for the development of therapies with which to either prevent or reverse paclitaxel-induced peripheral neuropathy in chemotherapy patients.

Increased Oxidative Stress as a Risk Factor in Chronic Idiopathic Axonal Polyneuropathy

Chronic idiopathic axonal polyneuropathy (CIAP) is a disorder with insidious onset and slow progression, where no etiology is identified despite appropriate investigations. We aimed to investigate the role of oxidative stress as a risk factor for the pathogenesis of CIAP. Sera of patients with CIAP were tested for protein carbonyl (PC) and 8-hydroxydeoxyguanosine (8H). As a control group, we recruited patients with gluten neuropathy. Twenty-one patients with CIAP and 21 controls were recruited. The two groups did not differ significantly regarding demographics or clinical characteristics (i.e., neuropathy type or disease severity). After adjusting for gender, having CIAP was positively correlated with both the 8H titer (standardized beta coefficient 0.349, p = 0.013) and the PC titer (standardized beta coefficient 0.469, p = 0.001). Oxidative stress appears to be increased in CIAP and might have a role in the pathogenesis of the disease.

Impact of GSTM1, GSTT1 and GSTP1 genes polymorphisms on clinical toxicities and response to concomitant chemoradiotherapy in cervical cancer

BACKGROUND

Certain forms of chemoradiotherapy generate toxic reactive oxygen species, which may be ameliorated by antioxidant enzymes such as glutathione S-transferase (GST). Genetic polymorphisms of GST may predict treatment outcomes and can be used as genetic marker to screen patients before treatment. We hypothesised an effect of GST polymorphisms on the response and toxicities produced by chemoradiation therapy.

MATERIALS AND METHODS

GST polymorphisms were determined by multiplex polymerase chain reaction and PCR-restriction fragment length polymorphism (PCR-RFLP) in 227 women with cervical cancer receiving cisplatin based chemoradiotherapy. Treatment response and toxicities were evaluated by standard internationally recognised criteria (RECIST and RTOG).

RESULTS

Severe (grade 3-4) gastrointestinal and haematological toxicities were present in 22 (9.4%) and 16 (7.0%) patients, respectively. GSTM1 null, GSTT1 null and GSTP1 AG genotypes brought marginally better non-significant associations. In single locus analysis GSTP1 AG and GG was linked to greatest risk of severe (grade 3-4) gastrointestinal toxicity (OR = 3.12, P = 0.035 and OR = 6.99, P = 0.01, respectively). In gene-gene interaction analysis, GSTM1 null-GSTP1 GG showed 4.2-fold higher risk of severe gastrointestinal toxicity (P = 0.014). GSTT1 null-GSTP1 AG reached statistical significance with a 3.9-fold higher risk of high grade gastrointestinal toxicity (P = 0.038).

CONCLUSIONS

Although no significant links were found between GST polymorphism and treatment response, null genotypes of GSTM1, GSTT1 and 'G' allele of GSTP1 bring a higher risk of severe gastrointestinal toxicity due to chemoradiation therapy in cervical cancer.

Predictive biomarkers of chemotherapy-induced peripheral neuropathy: a review

Chemotherapy-induced peripheral neuropathy (CIPN) is a common side effect of taxane treatment during chemotherapy. Identifying predictive biomarkers of CIPN would allow physicians to alter treatment given to patients according to a personal risk of developing this condition. The current literature on CIPN biomarkers is reviewed, identifying biomarkers which have been found to be significantly related to CIPN. Three genetic biomarkers are identified (ARHGEF10 rs9657362, CYP2C8 rs11572080/rs10509681 and FGD4 rs10771973) which have been found to act as predictive CIPN biomarkers in multiple studies. Possible mechanisms underlying the relationship between these single nucleotide polymorphisms and CIPN development are explored. The biomarkers identified in this study should be investigated further to generate predictive biomarkers that may be used in a clinical setting.

Effects of gene polymorphisms on the risk of severe hyponatremia during DCF chemotherapy for patients with esophageal squamous cell carcinoma

Combination chemotherapy using docetaxel, cisplatin and 5-fluorouracil (DCF) is a promising treatment option for patients with advanced esophageal squamous cell carcinoma (ESCC), although its clinical application is limited by severe systemic toxicities. There are no validated markers for predicting the adverse effects caused by this regimen. This pharmacogenetic study enrolled 57 patients with chemotherapy-naive advanced ESCC between July 2012 and March 2016 (UMIN000008462). All patients received at least one course of DCF chemotherapy (docetaxel, 60 mg/m² on day 1; cisplatin, 70 mg/m² on day 1; 5-fluorouracil, 600 mg/m² on days 1-5). The associations between four gene polymorphisms (ERCC1 rs11615, GSTP1 rs1695, TYMS rs151264360 and XPD rs13181) and the development of grade 3/4 adverse events during the first course of chemotherapy were prospectively investigated. The patients had a median age of 66 years (range, 45-77 years) and the majority were male (51 males vs. 6 females). The treatment settings were neoadjuvant (47 patients), adjuvant (1 patient) and salvage (9 patients), with dose intensities of 100% (51 patients) or 80% (6 patients). The severe adverse events were leukopenia (70.2%), neutropenia (86.0%), febrile neutropenia (36.8%), acute kidney injury (29.1%) and hyponatremia (43.9%). Two polymorphisms were independently associated with the development of severe hyponatremia among patients carrying the minor allele (vs. patients with major homozygote genotype): TYMS 3'-UTR rs151264360 (odds ratio, 3.64; 95% confidence interval, 1.11-11.9) and XPD Lys751Gln rs13181 (odds ratio, 10.1; 95% confidence interval, 1.10-93.3). Therefore, the presence of the TYMS and XPD polymorphisms may aid in identifying patients with a high risk of developing severe hyponatremia during DCF chemotherapy.

GSTP1 rs1695 is associated with both hematological toxicity and prognosis of ovarian cancer treated with paclitaxel plus carboplatin combination chemotherapy: a comprehensive analysis using targeted resequencing of 100 pharmacogenes

Purpose

To find genetic variants that predicted toxicity and/or efficacy of paclitaxel plus carboplatin combination therapy (TC therapy).

Patients and methods

In a retrospective case-control study, we analyzed 320 patients who had received TC therapy for gynecological cancers (ovarian, fallopian tube, peritoneal, uterine, and cervical cancers) and collected their germline DNA. We performed a comprehensive pharmacogenomic analysis using a targeted resequencing panel of 100 pharmacogenes. For 1,013 variants passing QC, case-control association studies and survival analyses were conducted.

Results

GSTP1 rs1695 showed the smallest p value for hematotoxicity association, and the ¹⁰⁵Ile wild type allele had a significantly higher risk of severe hematotoxicity (neutropenia G4, thrombocytopenia ≥ G3 and anemia ≥ G3) than the ¹⁰⁵Val allele (p=0.00034, odds ratio=5.71 (95% confidence interval:1.77-18.44)). Next, we assessed 5-year progression-free survival (PFS) and overall survival (OS) in 56 advanced ovarian cancer patients who received tri-weekly TC as a first-line chemotherapy. Patients with the ¹⁰⁵Ile/¹⁰⁵Ile genotype showed significantly better PFS (p=0.00070) and OS (p=0.0012) than those with the ¹⁰⁵Ile/¹⁰⁵Val or ¹⁰⁵Val/¹⁰⁵Val genotype.

Conclusion

Our study indicates that the GSTP1 rs1695 ¹⁰⁵Ile/¹⁰⁵Ile genotype is associated with both severe hematotoxicity and high efficacy of TC therapy, identifying a possible prognostic indicator for patients with TC therapy.

Efficacy and treatment-related adverse events of gemcitabine plus nab-paclitaxel for treatment of metastatic pancreatic cancer "in a Korean" population: A single-center cohort study

Pancreatic cancer has poor prognosis because of its rapid progression and treatment resistance. Based on the results of the Metastatic Pancreatic Adenocarcinoma Clinical Trial (MPACT), a combination regimen of gemcitabine with nab-paclitaxel is currently used as standard therapy for the treatment of metastatic pancreatic cancer. However, because studies in Asian populations are lacking, we investigated the treatment efficacy and safety of this combination therapy in Korean population. Patients with metastatic pancreatic cancer (n=81) treated with gemcitabine and nab-paclitaxel (1,000 and 125 mg/m², respectively) as the first-line chemotherapy from January 2016 were identified using the Severance Hospital Pancreatic Cancer Cohort Registry. Treatment efficacy and treatment-related adverse events (AEs) were analyzed. The median follow-up period was 10.7 months (range, 1.5-23.3 months). Median overall survival, progression-free survival, and objective response rates were 12.1 months (95% confidence interval [CI], 10.7-not estimable), 8.4 months (95% CI, 5.0-11.8), and 46.9%, respectively. The incidence of grade ≥3 neurotoxicity and neutropenia were 18.5% and 46.9%, respectively. Febrile neutropenia and grade ≥3 gastrointestinal AEs occurred in 13 (16.0%) and 16 (19.8%) patients, respectively. Dose reductions because of AEs were required in 60.5% of patients. The combination of gemcitabine with nab-paclitaxel is an effective anti-cancer regimen in Korean population of patients with metastatic pancreatic adenocarcinoma. However, careful monitoring and management are required because of occurrence of treatment-related AEs.

Clopidogrel in a combined therapy with anticancer drugs-effect on tumor growth, metastasis, and treatment toxicity: Studies in animal models

Clopidogrel, a thienopyridine derivative with antiplatelet activity, is widely prescribed for patients with cardiovascular diseases. In addition to antiplatelet activity, antiplatelet agents possess anticancer and antimetastatic properties. Contrary to this, results of some studies have suggested that the use of clopidogrel and other thienopyridines accelerates the progression of breast, colorectal, and prostate cancer. Therefore, in this study, we aimed to evaluate the efficacy of clopidogrel and various anticancer agents as a combined treatment using mouse models of breast, colorectal, and prostate cancer. Metastatic dissemination, selected parameters of platelet morphology and biochemistry, as well as angiogenesis were assessed. In addition, body weight, blood morphology, and biochemistry were evaluated to test toxicity of the studied compounds. According to the results, clopidogrel increased antitumor and/or antimetastatic activity of chemotherapeutics such as 5-fluorouracil, cyclophosphamide, and mitoxantrone, whereas it decreased the anticancer activity of doxorubicin, cisplatin, and tamoxifen. The mechanisms of such divergent activities may be based on the modulation of tumor vasculature via factors, such as transforming growth factor β1 released from platelets. Moreover, clopidogrel increased the toxicity of docetaxel and protected against mitoxantrone-induced toxicity, which may be due to the modulation of hepatic enzymes and protection of the vasculature, respectively. These results demonstrate that antiplatelet agents can be useful but also dangerous in anticancer treatment and therefore use of thienopyridines in patients undergoing chemotherapy should be carefully evaluated.

Independent replication of polymorphisms predicting toxicity in breast cancer patients randomized between dose-dense and docetaxel-containing adjuvant chemotherapy

Introduction

Although pharmacogenomics has evolved substantially, a predictive test for chemotherapy toxicity is still lacking. We compared the toxicity of adjuvant dose-dense doxorubicin-cyclophosphamide (ddAC) and docetaxel-doxorubicin-cyclophosphamide (TAC) in a randomized multicenter phase III trial and replicated previously reported associations between genotypes and toxicity.

Results

646 patients (97%) were evaluable for toxicity (grade 2 and higher). Whereas AN was more frequent after ddAC (P < 0.001), TAC treated patients more often had PNP (P < 0.001). We could replicate 2 previously reported associations: TECTA (rs1829; OR 4.18, 95% CI 1.84-9.51, P = 0.001) with PNP, and GSTP1 (rs1138272; OR 2.04, 95% CI 1.13-3.68, P = 0.018) with PNP.

Materials and methods

Patients with pT1-3, pN0-3 breast cancer were randomized between six cycles A60C600 every 2 weeks or T75A50C500 every 3 weeks. Associations of 13 previously reported single nucleotide polymorphisms (SNPs) with the most frequent toxicities: anemia (AN), febrile neutropenia (FN) and peripheral neuropathy (PNP) were analyzed using logistic regression models.

Conclusions

In this independent replication, we could replicate an association between 2 out of 13 SNPs and chemotherapy toxicities. These results warrant further validation in order to enable tailored treatment for breast cancer patients.

Assessment of Pharmacogenomic Panel Assay for Prediction of Taxane Toxicities: Preliminary Results

Backbone: Paclitaxel and docetaxel are the primary taxane anticancer drugs regularly used to treat, breast, gastric, ovarian, head/neck, lung, and genitourinary neoplasm. Suspension of taxane treatments compromising patient benefits is more frequently caused by peripheral neuropathy and allergy, than to tumor progression. Several strategies for preventing toxicity have been investigated so far. Recently, findings on the genetic variants associated with toxicity and resistance to taxane-based chemotherapy have been reported.

Methods: An extensive panel of five polymorphisms on four candidate genes (ABCB1, CYP2C8^*3, CYP3A4^*1B, XRCC3), previously validated as significant markers related to paclitaxel and Docetaxel toxicity, are analyzed and discussed. We genotyped 76 cancer patients, and 35 of them received paclitaxel or docetaxel-based therapy. What is more, an early outline evaluation of the genotyping costs and benefit was assessed.

Results: Out of 35 patients treated with a taxane, six (17.1%) had adverse neuropathy events. Pharmacogenomics analysis showed no correlation between candidate gene polymorphisms and toxicity, except for the XRCC3 AG+GG allele [OR 2.61 (95% CI: 0.91–7.61)] which showed a weak significant trend of risk of neurotoxicities vs. the AG allele [OR 1.52 (95% CI: 0.51–4.91)] P = 0.03.

Summary: Based on our experimental results and data from the literature, we propose a useful and low-cost genotyping panel assay for the prevention of toxicity in patients undergoing taxane-based therapy. With the individual pharmacogenomics profile, clinicians will have additional information to plan the better treatment for their patients to minimize toxicity and maximize benefits, including determining cost-effectiveness for national healthcare sustainability.

The molecular genetics of chemotherapy-induced peripheral neuropathy: A systematic review and meta-analysis

Chemotherapy-induced peripheral neuropathy (CIPN) can adversely affect completion of systemic anti-cancer treatment and cause long-term morbidity. Increasingly pharmacogenetic studies have been performed to explore susceptibility to this important adverse effect. A systematic review was conducted to identify pharmacogenetic studies, assess their quality and findings and undertake meta-analysis where possible. 93 studies were included. Notable methodological issues included lack of standardisation and detail in phenotype definition and acknowledgement of potential confounding factors. Insufficient data was presented in many studies meaning only a minority could be included in meta-analysis showing mainly non-significant effects. Nonetheless, SNPs in CYP2C8, CYP3A4, ARHGEF10, EPHA and TUBB2A genes (taxanes), FARS2, ACYP2 and TAC1 (oxaliplatin), and CEP75 and CYP3A5 (vincristine) are of potential interest. These require exploration in large cohort studies with robust methodology and well-defined phenotypes. Seeking standardisation of phenotype, collaboration and subsequently, individual-patient-data meta-analysis may facilitate identifying contributory SNPs which could be combined in a polygenic risk score to predict those most at risk of CIPN.

Identification of predictive markers of the therapeutic effect of eribulin chemotherapy for locally advanced or metastatic breast cancer

Background

The recently developed reagent, eribulin mesylate (eribulin), is a microtubule dynamics inhibitor with a mechanism of action that differs from those of taxanes and vinca alkaloids. This drug is considered to be a promising chemotherapeutic agent for the treatment of locally advanced or metastatic breast cancer (MBC). In this study, we investigated if variables such as tumor expression of β-tubulin class III, glutathione S-transferase pi (GSTP) 1 or transducin-like enhancer of split (TLE) 3 might act as predictive factors on the therapeutic effect of eribulin chemotherapy.

Methods

The subjects included 52 patients with MBC who underwent chemotherapy with eribulin. The expression levels of Estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor (HER) 2, Ki67, β-tubulin class III, GSTP-1 and TLE-3 were evaluated using immunostaining employing needle biopsy specimens.

Results

Patients with TLE3-negative tumors displayed significantly poorer outcomes regarding progression-free survival than patients with TLE3-positive tumors when prognosis within the group of patients with triple-negative breast cancer (TNBC) lesions was analyzed (p = 0.011, log-rank). In contrast, no such difference in prognosis was found in a comparison of TLE-3 positive/negative patients in the group of all patients (p = 0.433, log-rank) or of patients with non-TNBC lesions (p = 0.659, log-rank). Based on a univariate analysis of 22 TNBC cases, a better progression-free survival correlated significantly with a positive TLE3 expression in the tumor (p = 0.025). A multivariate logistic regression analysis including 22 patients with TNBC also showed that a positive TLE3 expression significantly correlated with a better progression-free survival (p = 0.037).

Conclusions

Our findings suggest that TLE3 is a useful marker for predicting the therapeutic effect of eribulin chemotherapy for TNBC.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3598-5) contains supplementary material, which is available to authorized users.

Energy landscape of a GSTP1 polymorph linked with cytological function decay in response to chemical stressors

Gene polymorphisms lead to varied structure and functional properties. A single nucleotide polymorphism (SNP) i.e. Ile105Val (rs1695) in glutathione S-transferase P1 (GSTP1) gene influences cytological toxicity and modulates the risk to occupational diseases. Apart from this, cancer, neuropathy, NOx, SOx and ozone mediated respiratory function decline including lung inflammation, asthma, allergy etc., have been reported in people with this missense mutation. Here, the functional properties of rs1695 polymorph are revisited through a computational approach. Changes incurred by GSTP1 antioxidant protein as a result of alteration in its sequence, have been studied through docking followed by Poisson-Boltzmann electrostatic equation interpretation, grid and coulombic energy profile mapping for protein polymorphs with DelPhi. Molecular docking simulation of variant and wild type (WT) protein was carried out with eight FDA approved compounds that target GSTP1 for treatment of various diseases. This was to observe binding pattern variation upon mutation induction. Grid, reaction field and coulombic energy calculation of WT and mutated polymorph, complexed with and without these moieties was then attempted. Alteration in conformation and energy was observed in apo- and holo- form of GSTP1 and their ligand-bound complexes as a result of this mutation. This study is a demo of appraising gene-environment interaction based deleteriousness through molecular docking and dynamics simulation approach.

Pharmacogenetic Discovery in CALGB (Alliance) 90401 and Mechanistic Validation of a VAC14 Polymorphism that Increases Risk of Docetaxel-Induced Neuropathy

PURPOSE

Discovery of SNPs that predict a patient's risk of docetaxel-induced neuropathy would enable treatment individualization to maximize efficacy and avoid unnecessary toxicity. The objectives of this analysis were to discover SNPs associated with docetaxel-induced neuropathy and mechanistically validate these associations in preclinical models of drug-induced neuropathy.

EXPERIMENTAL DESIGN

A genome-wide association study was conducted in metastatic castrate-resistant prostate cancer patients treated with docetaxel, prednisone and randomized to bevacizumab or placebo on CALGB 90401. SNPs were genotyped on the Illumina HumanHap610-Quad platform followed by rigorous quality control. The inference was conducted on the cumulative dose at occurrence of grade 3+ sensory neuropathy using a cause-specific hazard model that accounted for early treatment discontinuation. Genes with SNPs significantly associated with neuropathy were knocked down in cellular and mouse models of drug-induced neuropathy.

RESULTS

A total of 498,081 SNPs were analyzed in 623 Caucasian patients, 50 (8%) of whom experienced grade 3+ neuropathy. The 1,000 SNPs most associated with neuropathy clustered in relevant pathways including neuropathic pain and axonal guidance. An SNP in VAC14 (rs875858) surpassed genome-wide significance (P = 2.12 × 10^-8, adjusted P = 5.88 × 10^-7). siRNA knockdown of VAC14 in stem cell-derived peripheral neuronal cells increased docetaxel sensitivity as measured by decreased neurite processes (P = 0.0015) and branches (P < 0.0001). Prior to docetaxel treatment, VAC14 heterozygous mice had greater nociceptive sensitivity than wild-type litter mate controls (P = 0.001).

CONCLUSIONS

VAC14 should be prioritized for further validation of its potential role as a predictor of docetaxel-induced neuropathy and biomarker for treatment individualization. Clin Cancer Res; 22(19); 4890-900. ©2016 AACR.

Antioxidant Intake and Antitumor Therapy: Toward Nutritional Recommendations for Optimal Results

The role of the induction of oxidative stress as the mechanism of action of many antitumor drugs is acquiring an increasing interest. In such cases, the antitumor therapy success may be conditioned by the antioxidants present in our own body, which can be synthesized de novo (endogenous) or incorporated through the diet and nutritional supplements (exogenous). In this paper, we have reviewed different aspects of antioxidants, including their classification, natural sources, importance in diet, consumption of nutritional supplements, and the impact of antioxidants on health. Moreover, we have focused especially on the study of the interaction between antioxidants and antitumor therapy, considering both radiotherapy and chemotherapy. In this regard, we found that the convenience of administration of antioxidants during cancer treatment still remains a very controversial issue. In general terms, antioxidants could promote or suppress the effectiveness of antitumor treatment and even protect healthy tissues against damage induced by oxidative stress. The effects may depend on many factors discussed in the paper. These factors should be taken into consideration in order to achieve precise nutritional recommendations for patients. The evidence at the moment suggests that the supplementation or restriction of exogenous antioxidants during cancer treatment, as appropriate, could contribute to improving its efficiency.

Informative gene network for chemotherapy-induced peripheral neuropathy

BACKGROUND

Host genetic variability has been implicated in chemotherapy-induced peripheral neuropathy (CIPN). A dose-limiting toxicity for chemotherapy agents, CIPN is also a debilitating condition that may progress to chronic neuropathic pain. We utilized a bioinformatics approach, which captures the complexity of intracellular and intercellular interactions, to identify genes for CIPN.

METHODS

Using genes pooled from the literature as a starting point, we used Ingenuity Pathway Analysis (IPA) to generate gene networks for CIPN.

RESULTS

We performed IPA core analysis for genes associated with platinum-, taxane- and platinum-taxane-induced neuropathy. We found that IL6, TNF, CXCL8, IL1B and ERK1/2 were the top genes in terms of the number of connections in platinum-induced neuropathy and TP53, MYC, PARP1, P38 MAPK and TNF for combined taxane-platinum-induced neuropathy.

CONCLUSION

Neurotoxicity is common in cancer patients treated with platinum compounds and anti-microtubule agents and CIPN is one of the debilitating sequela. The bioinformatic approach helped identify genes associated with CIPN in cancer patients.

Management of side effects in the personalized medicine era: chemotherapy-induced peripheral neuropathy

Pharmacogenomics has been establishing itself as a powerful tool to predict individual response to treatment, in order to personalize therapy management; this field has been explored in particular in Oncology. Not only efficacy on the malignant disease has been investigated, but also the possibility to predict adverse effects due to drug administration. Chemotherapy-Induced Neurotoxicity (CIPN) is one of those. This potentially severe and long-lasting/permanent side effect of commonly administered anticancer drugs can severely impair Quality of Life (QoL) in a large cohort of long survival patients. So far, a pharmacogenomics-based approach in CIPN regard has been quite delusive, making a methodological improvement warranted in this field of interest: even the most refined genetic analysis cannot be effective if not applied correctly. Here, we try to devise why it is so, suggesting how THE "bench-side" (Pharmacogenomics) might benefit from and should cooperate with THE "bed-side" (Clinimetrics), in order to make genetic profiling effective if applied to CIPN.

Taxane induced neuropathy in patients affected by breast cancer: Literature review

Taxane induced neuropathy (TIN) is the most limiting side effect of taxane based chemotherapy, relative to the majority of breast cancer patients undergoing therapy with both docetaxel and paclitaxel. The symptoms begin symmetrically from the toes, because the tips of the longest nerves are affected for first. The patients report sensory symptoms such as paresthesia, dysesthesia, numbness, electric shock-like sensation, motor impairment and neuropathic pain. There is a great inter-individual variability among breast cancer women treated with taxanes, in fact 20-30% of them don't develop neurotoxicity. Actually, there is no standard therapy for TIN, although many medications, antioxidants and natural substances have been tested in vitro and in vivo. We will summarize all most recent literature data on TIN prevention and treatment, in order to reach an improvement in TIN management. Further studies are needed to evaluate new therapies that restore neuronal function and improve life quality of patients.

Docetaxel-induced neuropathy: a pharmacogenetic case-control study of 150 women with early-stage breast cancer

BACKGROUND

Docetaxel is a highly effective treatment of a wide range of malignancies but is often associated with peripheral neuropathy. The genetic variability of genes involved in the transportation or metabolism of docetaxel may be responsible for the variation in docetaxel-induced peripheral neuropathy (DIPN). The main purpose of this study was to investigate the impact of genetic variants in GSTP1 and ABCB1 on DIPN.

MATERIAL AND METHODS

DNA was extracted from whole blood from 150 patients with early-stage breast cancer who had received adjuvant docetaxel from February 2011 to May 2012. Two polymorphisms in GSTP1 and three in ABCB1 were selected for the primary analysis, and a host of other candidate genes was explored and compared between 75 patients with clinician-reported DIPN grade ≥ 2 and 75 patients without DIPN.

RESULTS

Patients with the genetic variants GSTP1 rs1138272 C/T or T/T (114Ala/114Val or 114Val/114Val) genotype had an adjusted odds ratio of 3.82; 95% confidence interval 1.34-11.09 of developing DIPN. This result was confirmed in both analysis of cumulated docetaxel dose and haplotype analysis. None of the explorative genes investigated were significantly correlated with DIPN. Patients with a BMI ≥ 30 were five-fold more likely to have DIPN than patients with BMI < 25.

CONCLUSION

We found that GSTP1 Ala114Val polymorphism is associated with occurrence of DIPN. This supports the theory that oxidative stress is involved in DIPN pathophysiology. If confirmed, this may be helpful in the risk assessment of DIPN and perhaps help to achieve better management of neurotoxicity.

Overview of neuropathy associated with taxanes for the treatment of metastatic breast cancer

Taxanes are an established option in the standard treatment paradigm for patients with metastatic breast cancer (MBC). Neuropathy is a common, dose-limiting side effect of taxane therapy that is often managed by dose reductions and delays. The severity, time to onset, and improvement in neuropathy are important considerations for patient management and vary among currently approved taxanes. The rate of grade ≥3 neuropathy with taxanes has been shown to be dose and schedule dependent; however, time to improvement to grade ≤1 is typically shorter for nab-paclitaxel than for other taxanes in patients with MBC. Many tools for assessing patient-reported neuropathy exist. Because MBC is incurable and patient quality of life must be critically considered when making treatment decisions, there is a need for more prospective trials to assess patient-reported neuropathy. Validated predictors of taxane-related neuropathy may play an important role in treatment decisions in the future. This review will focus on the toxicity profile (i.e., neuropathy) of each of the taxanes used in the treatment of MBC, will provide updates on tools used for the assessment of neuropathy, and will highlight newly discovered predictors of taxane-related neuropathy.

Genetic variability in drug transport, metabolism or DNA repair affecting toxicity of chemotherapy in ovarian cancer

Background

This study aimed to determine whether single nucleotide polymorphisms (SNPs) in genes involved in DNA repair or metabolism of taxanes or platinum could predict toxicity or response to first-line chemotherapy in ovarian cancer.

Methods

Twenty-six selected SNPs in 18 genes were genotyped in 322 patients treated with first-line paclitaxel-carboplatin or carboplatin mono-therapy. Genotypes were correlated with toxicity events (anemia, neutropenia, thrombocytopenia, febrile neutropenia, neurotoxicity), use of growth factors and survival.

Results

The risk of anemia was increased for variant alleles of rs1128503 (ABCB1, C > T; p = 0.023, OR = 1.71, 95% CI = 1.07-2.71), rs363717 (ABCA1, A > G; p = 0.002, OR = 2.08, 95% CI = 1.32-3.27) and rs11615 (ERCC1, T > C; p = 0.031, OR = 1.61, 95% CI = 1.04-2.50), while it was decreased for variant alleles of rs12762549 (ABCC2, C > G; p = 0.004, OR = 0.51, 95% CI = 0.33-0.81). Likewise, increased risk of thrombocytopenia was associated with rs4986910 (CYP3A4, T > C; p = 0.025, OR = 4.99, 95% CI = 1.22-20.31). No significant correlations were found for neurotoxicity. Variant alleles of rs2073337 (ABCC2, A > G; p = 0.039, OR = 0.60, 95% CI = 0.37-0.98), rs1695 (ABCC1, A > G; p = 0.017, OR = 0.55, 95% CI 0.33-0.90) and rs1799793 (ERCC2, G > A; p = 0.042, OR = 0.63, 95% CI 0.41-0.98) associated with the use of colony stimulating factors (CSF), while rs2074087 (ABCC1, G > C; p = 0.011, OR = 2.09, 95% CI 1.18-3.68) correlated with use of erythropoiesis stimulating agents (ESAs). Homozygous carriers of the rs1799793 (ERCC2, G > A) G-allele had a prolonged platinum-free interval (p = 0.016).

Conclusions

Our data reveal significant correlations between genetic variants of transport, hepatic metabolism, platinum related detoxification or DNA damage repair and toxicity or outcome in ovarian cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/s40360-015-0001-5) contains supplementary material, which is available to authorized users.

Replication of genetic polymorphisms reported to be associated with taxane-related sensory neuropathy in patients with early breast cancer treated with Paclitaxel

PURPOSE

Associations between taxane-related sensory neuropathy (TRSN) and single-nucleotide polymorphisms (SNP) have previously been reported, but few have been replicated in large, independent validation studies. This study evaluates the association between previously investigated SNPs and TRSN, using genotype data from a study of chemotherapy-related toxicity in patients with breast cancer.

EXPERIMENTAL DESIGN

We investigated 73 SNPs in 50 genes for their contribution to TRSN risk, using genotype data from 1,303 European patients. TRSN was assessed using National Cancer Institute common toxicity criteria for adverse events classification. Unconditional logistic regression evaluated the association between each SNP and TRSN risk (primary analysis). Cox regression analysis assessed the association between each SNP and cumulative taxane dose causing the first reported moderate/severe TRSN (secondary analysis). The admixture likelihood (AML) test, which considers all SNPs with a prior probability of association with TRSN together, tested the hypothesis that certain SNPs are truly associated.

RESULTS

The AML test provided strong evidence for the association of some SNPs with TRSN (P = 0.023). The two most significantly associated SNPs were rs3213619(ABCB1) [OR = 0.47; 95% confidence interval (CI), 0.28-0.79; P = 0.004] and rs9501929(TUBB2A) (OR = 1.80; 95% CI, 1.20-2.72; P = 0.005). A further 9 SNPs were significant at P-value ≤ 0.05.

CONCLUSION

This is currently the largest study investigating SNPs associated with TRSN. We found strong evidence that SNPs within genes in taxane pharmacokinetic and pharmacodynamic pathways contribute to TRSN risk. However, a large proportion of the inter-individual variability in TRSN remains unexplained. Further validated results from GWAS will help to identify new pathways, genes, and SNPs involved in TRSN susceptibility.

Toxic and drug-induced peripheral neuropathies: updates on causes, mechanisms and management

PURPOSE OF REVIEW

This review discusses publications highlighting current research on toxic, chemotherapy-induced peripheral neuropathies (CIPNs), and drug-induced peripheral neuropathies (DIPNs).

RECENT FINDINGS

The emphasis in clinical studies is on the early detection and grading of peripheral neuropathies, whereas recent studies in animal models have given insights into molecular mechanisms, with the discovery of novel neuronal, axonal, and Schwann cell targets. Some substances trigger inflammatory changes in the peripheral nerves. Pharmacogenetic techniques are underway to identify genes that may help to predict individuals at higher risk of developing DIPNs. Several papers have been published on chemoprotectants; however, to date, this approach has not been shown effective in clinical trials.

SUMMARY

Both length and nonlength-dependent neuropathies are encountered, including small-fiber involvement. The introduction of new diagnostic techniques, such as excitability studies, skin laser Doppler flowmetry, and pharmacogenetics, holds promise for early detection and to elucidate underlying mechanisms. New approaches to improve functions and quality of life in CIPN patients are discussed. Apart from developing less neurotoxic anticancer therapies, there is still hope to identify chemoprotective agents (erythropoietin and substances involved in the endocannabinoid system are promising) able to prevent or correct painful CIPNs.

Oxidative stress induced in rat liver by anticancer drugs doxorubicin, paclitaxel and docetaxel

PURPOSE

Oxidative stress generated by anticancer drugs in non-targeted tissues, is considered as a significant factor responsible for their severe side effects, e.g. cardiotoxicity, neurotoxicity and hepatotoxicity. Lack of data on the effect of concurrent administration of commonly used anticancer drugs: doxorubicin (DOX), paclitaxel (PTX) and docetaxel (DTX) on normal tissue, prompted us to examine the markers of oxidative stress in the liver of rats treated with these drugs.

MATERIAL/METHODS

Male Wistar rats of average weight 200 g were injected intraperitoneally (i.p.) with 10 mg/kg of body weight (b.w.) of DOX, PTX and DTX. The drugs were given alone or in combinations DOX+taxane. The activities of superoxide dismutase (SOD), catalase (CAT), low molecular weight and total thiols and thiobarbituric acid-reactive substances (TBARS) were estimated.

RESULTS

Combination of two drugs generated greater changes than single agents. Concurrent administration of DOX and PTX increased SOD activity and TBARS, decreased the amount of low molecular weight and total thiols, but did not cause any changes in the activity of catalase. Combination of DOX and DTX induced similar changes except for the activity of catalase, which decreased after the treatment. Of the three drugs only DTX significantly decreased the activity of SOD. However, both taxanes increased the activity of catalase. Although a decrease in concentration of -SH groups, depletion of glutathione and an increase of TBARS were observed after treatment with single drugs, the changes were not statistically significant.

CONCLUSION

Concurrent administration of DOX and taxane induced enhanced oxidative stress in comparison to single drugs, which suggests their synergistic prooxidant mode of action in liver.

Pathobiology of cancer chemotherapy-induced peripheral neuropathy (CIPN)

Chemotherapy induced peripheral neuropathy (CIPN) is a type of neuropathic pain that is a major dose-limiting side-effect of potentially curative cancer chemotherapy treatment regimens that develops in a "stocking and glove" distribution. When pain is severe, a change to less effective chemotherapy agents may be required, or patients may choose to discontinue treatment. Medications used to alleviate CIPN often lack efficacy and/or have unacceptable side-effects. Hence the unmet medical need for novel analgesics for relief of this painful condition has driven establishment of rodent models of CIPN. New insights on the pathobiology of CIPN gained using these models are discussed in this review. These include mitochondrial dysfunction and oxidative stress that are implicated as key mechanisms in the development of CIPN. Associated structural changes in peripheral nerves include neuronopathy, axonopathy and/or myelinopathy, especially intra-epidermal nerve fiber (IENF) degeneration. In patients with CIPN, loss of heat sensitivity is a hallmark symptom due to preferential damage to myelinated primary afferent sensory nerve fibers in the presence or absence of demyelination. The pathobiology of CIPN is complex as cancer chemotherapy treatment regimens frequently involve drug combinations. Adding to this complexity, there are also subtle differences in the pathobiological consequences of commonly used cancer chemotherapy drugs, viz platinum compounds, taxanes, vincristine, bortezomib, thalidomide and ixabepilone, on peripheral nerves.

Pharmacogenetics, enzyme probes and therapeutic drug monitoring as potential tools for individualizing taxane therapy

The taxanes are a class of chemotherapeutic agents that are widely used in the treatment of various solid tumors. Although taxanes are highly effective in cancer treatment, their use is associated with serious complications attributable to large interindividual variability in pharmacokinetics and a narrow therapeutic window. Unpredictable toxicity occurrence necessitates close patient monitoring while on therapy and adverse effects frequently require decreasing, delaying or even discontinuing taxane treatment. Currently, taxane dosing is based primarily on body surface area, ignoring other factors that are known to dictate variability in pharmacokinetics or outcome. This article discusses three potential strategies for individualizing taxane treatment based on patient information that can be collected before or during care. The clinical implementation of pharmacogenetics, enzyme probes or therapeutic drug monitoring could enable clinicians to personalize taxane treatment to enhance efficacy and/or limit toxicity.

Tubulin: an example of targeted chemotherapy

Anticancer drugs directed against the microtubule, including taxanes and vinca alkaloids, have been the backbone of many chemotherapy regimes for decades. These drugs have, however, significant limitations, which have prompted the development of novel microtubule targeting agents (MTAs). This article will discuss MTAs for anticancer therapies and recent debates regarding their mechanisms of action. Furthermore, the limitations of taxanes, including hypersensitivity reactions, neurotoxicity, drug resistance and lack of validated biomarkers to guide therapy will be discussed, all of which have driven the development of novel agents. The mechanisms of action and drug development of new generations of MTAs will also be outlined. Agents demonstrating utility in Phase III clinical trials, including eribulin, ixabepilone, cabazitaxel and trastuzumab-DM1 will be highlighted, as well as novel agents currently in development and future directions for MTAs.

Association between GSTP1 Ile105Val polymorphism and oxaliplatin-induced neuropathy: a systematic review and meta-analysis

BACKGROUND AND AIMS

The association between glutathione-S-transferase P1 (GSTP1) Ile105Val polymorphism and oxaliplatin-induced neuropathy has been investigated in a number of published studies. However, most of these studies were based on small sample sizes and the results remained inconsistent. To assess the relationship between GSTP1 gene Ile105Val polymorphism and its susceptibility to oxaliplatin-induced neuropathy, a meta-analysis of previous studies was conducted.

METHODS

Two investigators independently searched studies published up to December 2012 from the databases of PubMed, EMBASE and The Cochrane Library. The pooled effect was calculated as odds ratio (OR) and corresponding 95 % confidence intervals (CIs) using fixed-effect or random-effect model.

RESULTS

Twelve prospective trials and two retrospective clinical trials involving 2,191 participants met the inclusion criteria. Combined analyses of these studies showed no significant associations between GSTP1 Ile105Val polymorphism and oxaliplatin-induced neuropathy, yielding OR of 1.08 (95 %CI 0.67-1.74, P = 0.754) in dominant model. Similar results were also obtained in recessive model (OR = 1.67, 95 %CI 0.56-4.93, P = 0.357) and allelic analysis (OR = 1.22, 95 %CI 0.67-2.24, P = 0.513). Since significant heterogeneity across studies, the pooled effects were calculated by random-effect model. No evidence of publication biases was identified in this meta-analysis.

CONCLUSION

This meta-analysis did not support the hypothesis that GSTP1 Ile105Val polymorphism was related to the occurrence of neurotoxicity in oxaliplatin-treated patients. Given the limited number of studies and potential bias, large-scale and well-designed clinical trials should be needed to confirm these hypotheses.

Association between the rs1050450 glutathione peroxidase-1 (C > T) gene variant and peripheral neuropathy in two independent samples of subjects with diabetes mellitus

Glutathione peroxidase-1 (GPx-1) is an endogenous anti-oxidant enzyme. The T allele of the GPx-1 rs1050450 (C > T) gene variant is associated with reduced enzyme activity. Our aim was to examine the association between this gene variant and peripheral neuropathy in two cross-sectional samples of subjects with diabetes: (i) 773 Caucasian subjects were genotyped from the UCL Diabetes and Cardiovascular disease Study (UDACS) and (ii) 382 Caucasian subjects from the Ealing Diabetes Study (EDS). Peripheral neuropathy status (and oxidised-LDL [Ox-LDL:LDL] and plasma Total Ant-ioxidant Status [TAOS] in UDACS), were analysed in relation to genotype. We observed that: (i) In UDACS, the odds ratio (OR) for peripheral neuropathy in the T allele carriers compared to the CC genotype was 1.61 [1.10-2.28], p = 0.01. This remained significant after adjustment for other risk factors. Ox-LDL:LDL ratio was significantly elevated in T allele carriers (CC vs. CT/TT: 16.3 ± 2.4 v 18.0 ± 2.9 U/mmol LDL, p = 0.02). (ii) In EDS, the OR for peripheral neuropathy in the T allele carriers compared to the CC genotype was 1.95 [1.11-3.42], p = 0.02. This remained significant after adjustment for other risk factors. In conclusion, we observed a significant association between the T allele and peripheral neuropathy and LDL oxidation. This is the first paper to examine the rs1050450 variant in two samples of Caucasian subjects with diabetes. Prospective analysis of the gene variant is required in diabetic and healthy cohorts with measured plasma markers of oxidative stress to investigate the described association further.

Proposed medications for taxane-induced myalgia and arthralgia (Review)

Taxanes inhibit the disassembly of microtubules, which are involved in mitosis and axoplasmatic transport, and may cause the degeneration of peripheral, mainly small, sensory nerves. Peripheral neurotoxicity is a dose-limiting side-effect of taxanes. Neuroprotective agents may aid in the reduction of neurotoxicity, thus allowing the intensification of cytostatic therapy in patients. An increasing number of medications for the prevention of taxane-induced arthralgia and myalgia are becoming available to oncology teams. The most widely studied medications include so-called analgesics such as Shakuyaku-kanzo-to (a herbal medicine), corticosteroids and antihistamines. Arthralgias and myalgias (muscle spasms, fasciculations and prolonged contractions) may be extremely distressing for patients. New anti-epileptic drugs, particularly gabapentin and pregabalin, have proven to be safe and effective in the treatment of taxane-induced neurotoxicity. The aim of this review was to examine the topical choices available for the protective management of taxane-induced neurotoxicity monitored in preliminary case studies and clinical trials. At present, there is no standard of care for the prevention of taxane-induced arthralgia and myalgia. In combination with taxane-based chemotherapeutic regimens, these medical agents may be crucial in the treatment of a variety of types of cancer.

Genetic polymorphism of the glutathione-S-transferase P1 gene (GSTP1) and susceptibility to prostate cancer in the Kashmiri population

Glutathione-S-transferase P1 (GSTP1) is a critical enzyme of the phase II detoxification pathway. One of the common functional polymorphisms of GSTP1 is A→G at nucleotide 313, which results in an amino acid substitution (Ile105Val) at the substrate binding site of GSTP1 and reduces catalytic activity of GSTP1. To investigate the GSTP1 Ile105Val genotype frequency in prostate cancer cases in the Kashmiri population, we designed a case-control study, in which 50 prostate cancer cases and 45 benign prostate hyperplasia cases were studied for GSTP1 Ile105Val polymorphism, compared to 80 controls taken from the general population, employing the PCR-RFLP technique. We found the frequency of the three different genotypes of GSTP1 Ile105Val in our ethnic Kashmir population, i.e., Ile/Ile, Ile/Val and Val/Val, to be 52.4, 33.3 and 14.3% among prostate cancer cases, 48.5, 37.5 and 14% among benign prostate hyperplasia cases and 73.8, 21.3 and 5% in the control population, respectively. There was a significant association between the GSTP1 Ile/Val genotype and the advanced age group among the cases. We conclude that GSTP1 Ile/Val polymorphism is involved in the risk of prostate cancer development in our population.