Can pharmacogenetics explain efficacy and safety of cisplatin pharmacotherapy?

Pharmacogenomics in Cytotoxic Chemotherapy of Cancer

Pharmacogenetic testing in patients with cancer requiring cytotoxic chemotherapy offers the potential to predict, prevent, and mitigate chemotherapy-related toxicities. While multiple drug-gene pairs have been identified and studied, few drug-gene pairs are currently used routinely in the clinical status. Here we review what is known, theorized, and unknown regarding the use of pharmacogenetic testing in cancer.

A case-control study of a combination of single nucleotide polymorphisms and clinical parameters to predict clinically relevant toxicity associated with fluoropyrimidine and platinum-based chemotherapy in gastric cancer

Background

Fluoropyrimidine plus platinum chemotherapy remains the standard first line treatment for gastric cancer (GC). Guidelines exist for the clinical interpretation of four DPYD genotypes related to severe fluoropyrimidine toxicity within European populations. However, the frequency of these single nucleotide polymorphisms (SNPs) in the Latin American population is low (< 0.7%). No guidelines have been development for platinum. Herein, we present association between clinical factors and common SNPs in the development of grade 3–4 toxicity.

Methods

Retrospectively, 224 clinical records of GC patient were screened, of which 93 patients were incorporated into the study. Eleven SNPs with minor allelic frequency above 5% in GSTP1, ERCC2, ERCC1, TP53, UMPS, SHMT1, MTHFR, ABCC2 and DPYD were assessed. Association between patient clinical characteristics and toxicity was estimated using logistic regression models and classification algorithms.

Results

Reported grade ≤ 2 and 3–4 toxicities were 64.6% (61/93) and 34.4% (32/93) respectively. Selected DPYD SNPs were associated with higher toxicity (rs1801265; OR = 4.20; 95% CI = 1.70–10.95, p = 0.002), while others displayed a trend towards lower toxicity (rs1801159; OR = 0.45; 95% CI = 0.19–1.08; p = 0.071). Combination of paired SNPs demonstrated significant associations in DPYD (rs1801265), UMPS (rs1801019), ABCC2 (rs717620) and SHMT1 (rs1979277). Using multivariate logistic regression that combined age, sex, peri-operative chemotherapy, 5-FU regimen, the binary combination of the SNPs DPYD (rs1801265) + ABCC2 (rs717620), and DPYD (rs1801159) displayed the best predictive performance. A nomogram was constructed to assess the risk of developing overall toxicity.

Conclusion

Pending further validation, this model could predict chemotherapy associated toxicity and improve GC patient quality of life.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08745-0.

Impact of genetic factors on platinum-induced gastrointestinal toxicity

Severe gastrointestinal (GI) toxicity is a common side effect after platinum-based chemotherapy. The incidence and severity of GI toxicity vary among patients with the same chemotherapy. Genetic factors involved in platinum transport, metabolism, detoxification, DNA repair, cell cycle control, and apoptosis pathways may account for the interindividual difference in GI toxicity. The influence of gene polymorphisms in the platinum pathway on GI toxicity has been extensively analyzed. Variations in study sample size, ethnicity, design, treatment schedule, dosing, endpoint definition, and assessment of toxicity make it difficult to precisely interpret the results. Hence, we conducted a review to summarize the most recent pharmacogenomics studies of GI toxicity in platinum-based chemotherapy and identify the most promising avenues for further research.

Nano drug delivery systems in upper gastrointestinal cancer therapy

Upper gastrointestinal (GI) carcinomas are characterized as one of the deadliest cancer types with the highest recurrence rates. Their treatment is challenging due to late diagnosis, early metastasis formation, resistance to systemic therapy and complicated surgeries performed in poorly accessible locations. Current cancer medication face deficiencies such as high toxicity and systemic side-effects due to the non-specific distribution of the drug agent. Nanomedicine has the potential to offer sophisticated therapeutic possibilities through adjusted delivery systems. This review aims to provide an overview of novel approaches and perspectives on nanoparticle (NP) drug delivery systems for gastrointestinal carcinomas. Present regimen for the treatment of upper GI carcinomas are described prior to detailing various NP drug delivery formulations and their current and potential role in GI cancer theranostics with a specific emphasis on targeted nanodelivery systems. To date, only a handful of NP systems have met the standard of care requirements for GI carcinoma patients. However, an increasing number of studies provide evidence supporting NP-based diagnostic and therapeutic tools. Future development and strategic use of NP-based drug formulations will be a hallmark in the treatment of various cancers. This article seeks to highlight the exciting potential of novel NPs for targeted cancer therapy in GI carcinomas and thus provide motivation for further research in this field.

Systemic anti-cancer treatment in malignant ovarian germ cell tumours (MOGCTs): current management and promising approaches

Malignant ovarian germ cell tumours (MOGCTs) are rare. Unlike epithelial ovarian cancer, MOGCTs typically occur in girls and young women. Fertility-sparing surgery and platinum-based chemotherapy remain the standard of care, providing high chance of cure at all stages. Given the lack of high-quality studies in this field, current practice guidelines recommend chemotherapy regimens adopted in testicular germ cell tumours. However, platinum-resistant/refractory MOGCTs retain a worse prognosis in comparison with their male counterpart. Herein, we focus on current systemic anti-cancer treatment options in MOGCTs and promising approaches. Future studies enrolling exclusively female participants or germ cell tumour trials allowing participation of MOGCT patients are strongly recommended in order to improve evidence on existing management and develop novel strategies.

Genetic Polymorphisms and the Efficacy of Platinum-Based Chemotherapy: Review

Previous studies have indicated that genetic variations in individuals may result in changes in gene expression and amino acids. The effect of these changes may lead to different responses to platinum-based chemotherapy. A vast response rate interval and a short survival rate indicate that the efficacy and efficiency of the selection of chemotherapy have not been optimized. This article aims to illustrate the potential relationship of various genetic polymorphisms in response to platinum-based chemotherapy for several types of cancer. This review was conducted using articles from the last three- and five-year periods (2014-2019) that use gene polymorphism and its relationship to the efficacy of platinum-based chemotherapy as their theme. A total of 26 out of 488 relevant articles were included based on specific criteria. Through various mechanisms, genes, including ERCC1, ERCC2/XPD, XPC, XPA, XRCC1, APE-1, PARP1, OGG1, ABCC2, MRP, GSTP1, GSTM1, GSTT1, MATE1, and OCT2, have been associated with patient response to platinum-based chemotherapy. We conclude that genetic polymorphism analysis is recommended for the management of cancer so that each patient can be administered therapy based on his or her genetic profile to achieve an effective and efficient outcome.

First-Line Treatment with Olaparib for Early Stage BRCA-Positive Ovarian Cancer: May It Be Possible? Hypothesis Potentially Generating a Line of Research

Olaparib is currently approved in maintenance treatment of advanced ovarian cancer after response to first-line chemotherapy for breast related cancer antigens (BRCA) mutated patients. The use of this agent is based on data from SOLO1 study that observed a decreased risk of disease progression or death and a median progression-free survival about 36 months longer in case of therapy with olaparib. However, this trial recruited only patients with advanced stage ovarian cancer. The aim of this review is to retrace the available data in order to clarify the potential efficacy and feasibility of olaparib administration in newly diagnosed epithelial ovarian cancer also in early stages.

FAS and FASL variations in outcomes of tobacco- and alcohol-related head and neck squamous cell carcinoma patients

Radiotherapy and cisplatin lead to cell killing in head and neck squamous cell carcinoma patients, but adverse events and response to treatment are not the same in patients with similar clinicopathological aspects. The aim of this prospective study was to evaluate the roles of TP53 c.215G > C, FAS c.-671A > G, FAS c.-1378G > A, FASL c.-844 C > T, CASP3 c.-1191A > G, and CASP3 c.-182-247G > T single nucleotide variants in toxicity, response rate, and survival of cisplatin chemoradiation-treated head and neck squamous cell carcinoma patients. Genomic DNA was analyzed by polymerase chain reaction for genotyping. Differences between groups of patients were analyzed by chi-square test or Fisher's exact test, multiple logistic regression analysis, and Cox hazards model. One hundred nine patients with head and neck squamous cell carcinoma were enrolled in study. All patients were smokers and/or alcoholics. Patients with FAS c.-671GG genotype, FAS c.-671AG or GG genotype, and FASL c.-844CC genotype had 5.52 (95% confidence interval (CI): 1.42-21.43), 4.03 (95% CI: 1.51-10.79), and 5.77 (95% CI: 1.23-27.04) more chances of presenting chemoradiation-related anemia of grades 2-4, lymphopenia of grade 3 or 4, and ototoxicity of all grades, respectively, than those with the remaining genotypes. FAS c.-671GG genotype was also seen as an independent predictor of shorter event-free survival (hazard ratio (HR): 2.05; P = 0.007) and overall survival (HR: 1.83; P = 0.02) in our head and neck squamous cell carcinoma patients. These findings present, for the first time, preliminary evidence that inherited abnormalities in apoptosis pathway, related to FAS c.-671A > G and FASL c.-844 C > T single nucleotide variants, can alter toxicity and survival of tobacco- and alcohol-related head and neck squamous cell carcinoma patients homogeneously treated with cisplatin chemoradiation.

Association Study Among Candidate Genetic Polymorphisms and Chemotherapy-Related Severe Toxicity in Testicular Cancer Patients

Testicular cancer is one of the most commonly occurring malignant tumors in young men with fourfold higher rate of incidence and threefold higher mortality rates in Chile than the average global rates. Surgery is the initial line of treatment for testicular cancers, and is generally followed by chemotherapy, usually with combinations of bleomycin, etoposide, and cisplatin (BEP). However, the adverse effects of chemotherapy vary significantly among individuals; therefore, the present study explored the association of functionally significant allelic variations in genes related to the pharmacokinetics/pharmacodynamics of BEP and DNA repair enzymes with chemotherapy-induced toxicity in BEP-treated testicular cancer patients. We prospectively recruited 119 patients diagnosed with testicular cancer from 2010 to 2017. Genetic polymorphisms were analyzed using PCR and/or qPCR with TaqMan^®probes. Toxicity was evaluated based on the Common Terminology Criteria for Adverse Events, v4.03. After univariate analyses to define more relevant genetic variants (p < 0.2) and clinical conditions in relation to severe (III–IV) adverse drug reactions (ADRs), stepwise forward multivariate logistic regression analyses were performed. As expected, the main severe ADRs associated with the non-genetic variables were hematological (neutropenia and leukopenia). Univariate statistical analyses revealed that patients with ERCC2 rs13181 T/G and/or CYP3A4 rs2740574 A/G genotypes are more likely to develop alopecia; patients with ERCC2 rs238406 C/C genotype may develop leukopenia, and patients with GSTT1-null genotype could develop lymphocytopenia (III–IV). Patients with ERCC2 rs1799793 A/A were at risk of developing severe anemia. The BLMH rs1050565 G/G genotype was found to be associated with pain, and the GSTP1 G/G genotype was linked infection (p < 0.05). Multivariate analysis showed an association between specific ERCC1/2 genotypes and cumulative dose of BEP drugs with the appearance of severe leukopenia and/or febrile neutropenia. Grades III–IV vomiting, nausea, and alopecia could be partly explained by the presence of specific ERCC1/2, MDR1, GSTP1, and BLMH genotypes (p < 0.05). Hence, we provide evidence for the usefulness of pharmacogenetics as a tool for predicting severe ADRs in testicular cancer patients treated with BEP chemotherapy.

Glutathione Transferases: Potential Targets to Overcome Chemoresistance in Solid Tumors

Multifunctional enzymes glutathione transferases (GSTs) are involved in the development of chemoresistance, thus representing a promising target for a novel approach in cancer treatment. This superfamily of polymorphic enzymes exhibits extraordinary substrate promiscuity responsible for detoxification of numerous conventional chemotherapeutics, at the same time regulating signaling pathways involved in cell proliferation and apoptosis. In addition to upregulated GST expression, different cancer cell types have a unique GST signature, enabling targeted selectivity for isoenzyme specific inhibitors and pro-drugs. As a result of extensive research, certain GST inhibitors are already tested in clinical trials. Catalytic properties of GST isoenzymes are also exploited in bio-activation of specific pro-drugs, enabling their targeted accumulation in cancer cells with upregulated expression of the appropriate GST isoenzyme. Moreover, the latest approach to increase specificity in treatment of solid tumors is development of GST pro-drugs that are derivatives of conventional anti-cancer drugs. A future perspective is based on the design of new drugs, which would selectively target GST overexpressing cancers more prone to developing chemoresistance, while decreasing side effects in off-target cells.

Association between genetic polymorphisms and platinum-induced ototoxicity in children

Platinum is extensively used in the treatment of several childhood cancers. However, ototoxicity is one of the most notable adverse effects, especially in children. Several studies suggest that genetics may predict its occurrence. Here, polymorphisms associated with platinum-induced ototoxicity were selected from the literature and were investigated in a pediatric population treated with platinum-based agents. In this retrospective study, patients treated with cisplatin and/or carboplatin were screened. The patients with pre- and post-treatment audiogram (Brock criteria) available were included. We selected polymorphisms that have previously been associated with cisplatin ototoxicity with a minor allele frequency ≥30%. Deletion of GSTM1 and GSTT1, rs1799735 (GSTM3), rs1695 (GSTP1), rs4880 (SOD2), rs2228001 (XPC), rs1799793 (XPD) and rs4788863 (SLC16A5) were investigated. Data of one hundred and six children matching the eligible criteria were analyzed. Thirty-three patients (31%) developed ototoxicity (with a Brock grade ≥2). The probability of hearing loss increased significantly in patients carrying the null genotype for GSTT1 (P = 0.03), A/A genotype at rs1695 (P = 0.01), and C/C genotype at rs1799793 (P = 0.008). We also showed an association of the cumulative doses of carboplatin with cisplatin ototoxicity (P <0.05). To conclude, deletion of GSTT1, rs1695 and rs1799793 may constitute potential predictors of platinum-induced ototoxicity.

Pharmacogenetics of platinum-based chemotherapy in non-small cell lung cancer: predictive validity of polymorphisms of ERCC1

INTRODUCTION

The efficacy of platinum-based chemotherapy for patients with non-small cell lung cancer (NSCLC) is limited by chemoresistance. Platinum drugs damage DNA by introducing intrastrand and interstrand crosslinks which result in cell death. Excision repair cross-complementing 1 (ERCC1) is a member of the nucleotide excision repair (NER) pathway which erases such defects. Single nucleotide polymorphisms (SNPs) in ERCC1 impair this activity and have been suggested to predict the response to chemotherapy. Area covered: Among the polymorphisms of proteins involved in uptake, metabolism, cytotoxicity and efflux of platinum drugs, codon 118 C/T and C8092A in ERCC1 are the best characterized SNPs studied for their predictive power. Here, the divergent results for studies of these markers in NSCLC are summarized and the reasons for this contradictory data discussed. Expert opinion: Cytotoxicity of platinum compounds comprise complex cellular processes for which DNA repair may not constitute the rate limiting step. These drugs are administered as doublets to histologically diverse patients and, furthermore, the NER pathway in ERCC1 wildtype cohorts may be still impaired by the chemotherapeutics applied. At present, assessment of a limited number of polymorphism in DNA repair proteins is not reliably associated with response to treatment in NSCLC patients.

Relationship between clinical toxicities and ERCC1 rs3212986 and XRCC3 rs861539 polymorphisms in cervical cancer patients

BACKGROUND

Several studies have suggested that there are single nucleotide polymorphisms (SNPs) that can be considered potential biomarkers in the prognosis and therapeutic response of cancer patients. The present study investigated the association between ERCC1 rs3212986 and XRCC3 rs861539 polymorphisms and clinical toxicities induced by chemoradiotherapy (CRT) in cervical cancer.

METHODS

This hospital-based retrospective cohort study included 260 patients with cervical cancer, FIGO stages Ib2-IVa, who underwent CRT (cisplatin). Genetic polymorphisms analysis was performed by allelic discrimination with real-time polymerase chain reaction (RT-PCR).

RESULTS

Our results indicated a link between ERCC1 rs3212986 and the onset of late gastrointestinal toxicity (p = 0.038). Furthermore, using a recessive model (AA vs. CC/CA), we found that patients carrying AA homozygous genotype presented a fourfold increased risk of developing late gastrointestinal toxicity when compared with patients with the C allele (odds ratio = 3.727, 95% confidence interval, 1.199-11.588; p = 0.017). No association was found regarding the XRCC3 rs861539 polymorphism and any clinical toxicity event.

CONCLUSIONS

This is the first study evaluating the relationship between these polymorphisms and clinical toxicities in cervical cancer patients submitted to CRT with cisplatin. These results may contribute toward a better understanding of the influence of genetic polymorphisms in genes associated with DNA repair in the clinical response to CRT of patients with cervical cancer.

Genotypes Affecting the Pharmacokinetics of Anticancer Drugs

Cancer treatment is becoming more and more individually based as a result of the large inter-individual differences that exist in treatment outcome and toxicity when patients are treated using population-based drug doses. Polymorphisms in genes encoding drug-metabolizing enzymes and transporters can significantly influence uptake, metabolism, and elimination of anticancer drugs. As a result, the altered pharmacokinetics can greatly influence drug efficacy and toxicity. Pharmacogenetic screening and/or drug-specific phenotyping of cancer patients eligible for treatment with chemotherapeutic drugs, prior to the start of anticancer treatment, can identify patients with tumors that are likely to be responsive or resistant to the proposed drugs. Similarly, the identification of patients with an increased risk of developing toxicity would allow either dose adaptation or the application of other targeted therapies. This review focuses on the role of genetic polymorphisms significantly altering the pharmacokinetics of anticancer drugs. Polymorphisms in DPYD, TPMT, and UGT1A1 have been described that have a major impact on the pharmacokinetics of 5-fluorouracil, mercaptopurine, and irinotecan, respectively. For other drugs, however, the association of polymorphisms with pharmacokinetics is less clear. To date, the influence of genetic variations on the pharmacokinetics of the increasingly used monoclonal antibodies has hardly been investigated. Some studies indicate that genes encoding the Fcγ-receptor family are of interest, but more research is needed to establish if screening before the start of therapy is beneficial. Considering the profound impact of polymorphisms in drug transporters and drug-metabolizing enzymes on the pharmacokinetics of chemotherapeutic drugs and hence, their toxicity and efficacy, pharmacogenetic and pharmacokinetic profiling should become the standard of care.

M3 Macrophages Stop Division of Tumor Cells In Vitro and Extend Survival of Mice with Ehrlich Ascites Carcinoma

Background

M1 macrophages target tumor cells. However, many tumors produce anti-inflammatory cytokines, which reprogram the anti-tumor M1 macrophages into the pro-tumor M2 macrophages. We have hypothesized that the problem of pro-tumor macrophage reprogramming could be solved by using a special M3 switch phenotype. The M3 macrophages, in contrast to the M1 macrophages, should respond to anti-inflammatory cytokines by increasing production of pro-inflammatory cytokines to retain its anti-tumor properties. Objectives of the study were to form an M3 switch phenotype in vitro and to evaluate the effect of M3 macrophages on growth of Ehrlich ascites carcinoma (EAC) in vitro and in vivo.

Material/Methods

Tumor growth was initiated by an intraperitoneal injection of EAC cells into C57BL/6J mice.

Results

1) The M3 switch phenotype can be programed by activation of M1-reprogramming pathways with simultaneous inhibition of the M2 phenotype transcription factors, STAT3, STAT6, and/or SMAD3. 2) M3 macrophages exerted an anti-tumor effect both in vitro and in vivo, which was superior to anti-tumor effects of cisplatin or M1 macrophages. 3) The anti-tumor effect of M3 macrophages was due to their anti-proliferative effect.

Conclusions

Development of new biotechnologies for restriction of tumor growth using in vitro reprogrammed M3 macrophages is very promising.

Genome-wide association study identifies four SNPs associated with response to platinum-based neoadjuvant chemotherapy for cervical cancer

To identify genomic markers associated with the response to neoadjuvant chemotherapy (NACT) in patients with cervical cancer, we performed a three-stage genome-wide association study (GWAS) in the Han Chinese population. A total of 596 patients with stage IA2-IIIB cervical cancer were enrolled in this study. One single nucleotide polymorphism (SNP) (rs6812281, per allele OR = 2.37, P = 9.0 × 10⁻⁹) located at 4q34.3 reached GWAS significance (P < 5.0 × 10⁻⁸). Another three SNPs, rs4590782 (10q26.2, P = 1.59 × 10⁻⁵, per allele OR = 0.48), rs1742101 (14q32.11, P = 7.11 × 10⁻⁶, per allele OR = 0.52), and rs1364121 (16q23.3, P = 3.15 × 10⁻⁶, per allele OR = 1.98), exhibited strong evidence of associations with response to neoadjuvant chemotherapy. Patients with a C allele (CT + CC) of rs4590782 had better 5-year overall survival rates (82.9% vs. 75.8%, P = 0.083) and 5-year disease-free survival rate (80.8% vs. 72.7%, P = 0.021) than those without a C allele. Our findings help to characterize the genetic etiology of the response to neoadjuvant chemotherapy in patients with cervical cancer.

Neuroblastoma

Neuroblastoma is the most common extracranial solid tumour occurring in childhood and has a diverse clinical presentation and course depending on the tumour biology. Unique features of these neuroendocrine tumours are the early age of onset, the high frequency of metastatic disease at diagnosis and the tendency for spontaneous regression of tumours in infancy. The most malignant tumours have amplification of the MYCN oncogene (encoding a transcription factor), which is usually associated with poor survival, even in localized disease. Although transgenic mouse models have shown that MYCN overexpression can be a tumour-initiating factor, many other cooperating genes and tumour suppressor genes are still under investigation and might also have a role in tumour development. Segmental chromosome alterations are frequent in neuroblastoma and are associated with worse outcome. The rare familial neuroblastomas are usually associated with germline mutations in ALK, which is mutated in 10-15% of primary tumours, and provides a potential therapeutic target. Risk-stratified therapy has facilitated the reduction of therapy for children with low-risk and intermediate-risk disease. Advances in therapy for patients with high-risk disease include intensive induction chemotherapy and myeloablative chemotherapy, followed by the treatment of minimal residual disease using differentiation therapy and immunotherapy; these have improved 5-year overall survival to 50%. Currently, new approaches targeting the noradrenaline transporter, genetic pathways and the tumour microenvironment hold promise for further improvements in survival and long-term quality of life.

Predictive role of host constitutive variants in neoadjuvant therapy of esophageal cancer

Chemoradiotherapy followed by surgery is at present the standard therapeutic approach for esophageal cancer (EC) in patients with resectable tumor. However, response to neoadjuvant therapy is characterized by a strong interpatient variability, and the identification of markers predictive of outcome is mandatory. In this review, taking into account the currently available literature, we report the impact that host genetic variables can have on EC neoadjuvant therapy. We mainly focused on the gene variants involved in the pharmacokinetics and pharmacodynamics of the common chemotherapeutic drugs used to treat EC patients, commented on the weakness of the present knowledge, and discussed the future strategies to achieve a more personalized and effective EC treatment.

A germline predictive signature of response to platinum chemotherapy in esophageal cancer

Platinum-based neoadjuvant therapy is the standard treatment for esophageal cancer (EC). At present, no reliable response markers exist, and patient therapeutic outcome is variable and very often unpredictable. The aim of this study was to understand the contribution of host constitutive DNA polymorphisms in discriminating between responder and nonresponder patients. DNA collected from 120 EC patients treated with platinum-based neoadjuvant chemotherapy was analyzed using drug metabolism enzymes and transporters (DMET) array platform that interrogates polymorphisms in 225 genes of drug metabolism and disposition. Four gene variants of DNA repair machinery, 2 in ERCC1 (rs11615; rs3212986), and 2 in XPD (rs1799793; rs13181) were also studied. Association analysis was performed with pTest software and corrected by permutation test. Predictive models of response were created using the receiver-operating characteristics curve approach and adjusted by the bootstrap procedure. Sixteen single nucleotide polymorphisms (SNPs) of the DMET array resulted significantly associated with either good or poor response; no association was found for the 4 variants mapping in DNA repair genes. The predictive power of 5 DMET SNPs mapping in ABCC2, ABCC3, CYP2A6, PPARG, and SLC7A8 genes was greater than that of clinical factors alone (area under the curve [AUC] = 0.74 vs 0.62). Interestingly, their combination with the clinical variables significantly increased the predictivity of the model (AUC = 0.78 vs 0.62, P = 0.0016). In conclusion, we identified a genetic signature of response to platinum-based neoadjuvant chemotherapy in EC patients. Our results also disclose the potential benefit of combining genetic and clinical variables for personalized EC management.

Macrophages Reprogrammed In Vitro Towards the M1 Phenotype and Activated with LPS Extend Lifespan of Mice with Ehrlich Ascites Carcinoma

Background

The majority of tumors trigger macrophage reprogramming from an anti-tumor M1 phenotype towards a pro-tumor M2 phenotype. The M2 phenotype promotes tumor growth. We hypothesized that increasing the number of M1 macrophages in a tumor would limit carcinogenesis and extend the lifespan of the tumor host. The aim of this study was to verify this hypothesis in Ehrlich ascites carcinoma (EAC). The objectives were to evaluate effects of 1) EAC on a macrophage phenotype and NO-producing macrophage activity in vivo; 2) ascitic fluid from mice with EAC on a macrophage phenotype and NO-producing macrophage activity in vitro; and 3) in vitro reprogrammed M1 macrophages on lifespan of mice with EAC.

Material/Methods

The study was conducted using C57BL/6J mice.

Results

Concentration of nitrite, a stable NO metabolite and an index of NO production, was measured spectrophotometrically. Shifts of macrophage phenotype were assessed by changes in NO production as well as by amounts of CD80, a marker of M1 phenotype, and CD206, a marker of M2 phenotype. The CD markers were measured by flow cytometry. Macrophages were reprogrammed towards the M1 phenotype using two reprogramming factors: 0% FBS and 20 ng/ml IFN-γ. The study results showed that 1) EAC inhibited the macrophage NO production in vivo and reprogrammed macrophages towards the M2 phenotype; 2) ascitic fluid of mice with EAC inhibited the macrophage NO production in vitro and reprogrammed macrophages towards the M2 phenotype; and 3) injection of in vitro reprogrammed M1 macrophages into mice with EAC significantly increased the lifespan of mice.

Conclusions

These findings suggest that promising biotechnologies for restriction of tumor growth could be developed based on the in vitro macrophage reprogramming.