Hypoxia can impair doxorubicin resistance of non-small cell lung cancer cells by inhibiting MRP1 and P-gp expression and boosting the chemosensitizing effects of MRP1 and P-gp blockers

Background

Non-small cell lung cancers (NSCLCs) frequently exhibit resistance to therapeutic drugs, which seriously hampers their treatment. Here, we set out to assess the roles of the multidrug resistance protein 1 (MRP1) and P-glycoprotein (P-gp) in the doxorubicin (DOX) resistance of NSCLC cells, as well as the putative therapeutic efficacy of MRP1 and P-gp blockers on DOX-treated NSCLC cells.

Methods

The impact of DOX on cell survival, DOX efflux and MRP1 and P-gp expression was assessed in 5 different NSCLC-derived cell lines (parental CH27, A549, H1299, H460, and DOX resistant CH27) in the absence or presence of MK571 (MRP1 inhibitor) or Verapamil (P-gp inhibitor), under both normoxic and hypoxic conditions.

Results

We found that in response to DOX treatment, NSCLC cells that express high levels of MRP1 and P-gp (such as CH27) showed a better DOX efflux and a higher DOX resistance. MK571 and Verapamil were found to abolish DOX resistance and to act as chemosensitizers for DOX therapy in all cell lines tested. We also found that hypoxia could inhibit MRP1 and P-gp expression in a HIF-1α-dependent manner, abolish DOX resistance and boost the chemosensitizer effect of MK571 and Verapamil on DOX treatment of all the NSCLC cells tested, except the DOX-resistant CH27 cells.

Conclusions

From our data we conclude that MRP1 and P-gp play critical roles in the DOX resistance of the NSCLC cells tested. MRP1 and P-gp targeted therapy using MK571, Verapamil, CoCl₂ or ambient hypoxia appeared to be promising in abolishing the DOX efflux and DOX resistance of the NSCLC cells. The putative therapeutic efficacies of MRP1 and/or P-gp blockers on NSCLC cells are worthy of note.

     

Targeting CXCR4 and FAK reverses doxorubicin resistance and suppresses invasion in non-small cell lung carcinoma

Background

Current high lung cancer mortality rates are mainly due to the occurrence of metastases and therapeutic resistance. Therefore, simultaneous targeting of these processes may be a valid approach for the treatment of this type of cancer. Here, we assessed relationships between CXC chemokine receptor type 4 (CXCR4) and focal adhesion kinase (FAK) gene expression levels and expression levels of the drug resistance-related genes ABCB1 and ABCC1, and tested the potential of CXCR4 and FAK inhibitors to reverse doxorubicin (DOX) resistance and to decrease the invasive capacity of non-small cell lung carcinoma (NSCLC) cells.

Methods

qRT-PCR was used for gene expression analyses in primary lung tissue samples obtained from 30 NSCLC patients and the human NSCLC-derived cell lines NCI-H460, NCI-H460/R and COR-L23. MTT, flow cytometry, cell death and β-galactosidase activity assays were used to assess the in vitro impact of CXCR4 and FAK inhibitors on DOX sensitivity. In addition, invasion and gelatin degradation assays were used to assess the in vitro impact of the respective inhibitors on metastasis-related processes in combination with DOX treatment.

Results

We found that ABCB1 over-expression was significantly associated with CXCR4 and FAK over-expression, whereas ABCC1 over-expression was associated with increased FAK expression. We also found that CXCR4 and FAK inhibitors strongly synergized with DOX in reducing cell viability, arresting the cell cycle in the S or G₂/M phases and inducing senescence. Additionally, we found that DOX enhanced the anti-invasive potential of CXCR4 and FAK inhibitors by reducing gelatin degradation and invasion.

Conclusions

From our data we conclude that targeting of CXCR4 and FAK may overcome ABCB1 and ABCC1-dependent DOX resistance in NSCLC cells and that simultaneous treatment of these cells with DOX may potentiate the anti-invasive effects of CXCR4 and FAK inhibitors.

     

Prognostic value of glucosylceramide synthase and P-glycoprotein expression in oral cavity cancer

Background

Glucosylceramide synthase (GCS) and P-glycoprotein (P-gp) overexpression are associated with multidrug resistance in several human cancers. This study investigated the prognostic value of GCS and P-gp in oral cavity squamous cell carcinoma (OSCC).

Methods

The association between GCS and P-gp overexpression and clinical outcomes was assessed in 186 human clinical specimens of primary tumors obtained from curative surgery. Immunohistochemistry staining results were scored as high or low for GCS, and positive or negative for P-gp. Univariate and multivariate analyses using the Cox proportional hazards model were conducted to assess the significance of differences in recurrence or survival outcomes between variables.

Results

GCS overexpression was observed in 128 (68.8 %) patients and P-gp overexpression in 43 (23.1 %) patients. High GCS expression was significantly correlated with P-gp immunopositivity (P = 0.005). GCS and P-gp overexpression was significantly correlated with cervical nodal metastasis (P < 0.05). Univariate analyses showed that tumor lymphovascular invasion, positive neck lymph nodes, advanced overall TNM stage, high GCS expression, and P-gp immunopositivity were associated with poor locoregional control (LRC), disease-free survival (DFS), and overall survival (OS) (P < 0.05). Multivariate analyses showed that lymphovascular invasion, nodal positivity, and P-gp overexpression remained independent prognostic variables for LRC, DFS, and OS, and that GCS expression was an independent predictor of LRC and DFS (P < 0.05).

Conclusion

GCS and P-gp expression is associated with poor prognosis, suggesting suitability as novel biomarkers in OSCC.

     

miR-668 enhances the radioresistance of human breast cancer cell by targeting IκBα

Background

A large proportion of breast cancer patients are resistant to radiotherapy, which is a mainstay treatment for this malignancy, but the mechanisms of radioresistance remain unclear.

Methods and materials

To evaluate the role of miRNAs in radioresistance, we established two radioresistant breast cancer cell lines MCF-7R and T-47DR derived from parental MCF-7 and T-47D. Moreover, miRNA microarray, quantitative RT-PCR analysis, luciferase reporter assay and western blotting were used.

Results

We found that miR-668 was most abundantly expressed in radioresistant cells MCF-7R and T-47DR. miR-668 knockdown reversed radioresistance of MCF-7R and T-47DR, miR-668 overexpression enhanced radioresistance of MCF-7 and T-47D cells. Mechanically, bioinformatics analysis combined with experimental analysis demonstrated IκBα, a tumor-suppressor as well as an NF-κB inhibitor, was a direct target of miR-668. Further, miR-668 overexpression inhibited IκBα expression, activated NF-κB, thus, increased radioresistance of MCF-7 and T-47D cells. Conversely, miR-668 knockdown restored IκBα expression, suppressed NF-κB, increased radiosensitivity of MCF-7R and T-47DR cells.

Conclusion

Our findings suggest miR-668 is involved in the radioresistance of breast cancer cells and miR-668-IκBα-NF-κB axis may be a novel candidate for developing rational therapeutic strategies for human breast cancer treatment.

     

Efficacy of doxorubicin-transferrin conjugate in apoptosis induction in human leukemia cells through reactive oxygen species generation

Background

Doxorubicin (DOX) is a small molecular cytotoxic agent that can be transferred efficiently to cancer cells by nanocarriers. This anthracycline antibiotic serves as an effective anti-neoplastic drug against both hematological and solid malignancies. Here, we set out to assess the capacity of a novel doxorubicin - transferrin conjugate (DOX-TRF) to provoke apoptosis in human normal and leukemia cells through free radicals produced via a redox cycle of doxorubicin (DOX) when released from its conjugate.

Methods

After DOX-TRF exposure, we determined the time-course of apoptotic and necrotic events, the generation of reactive oxygen species (ROS), changes in mitochondrial membrane potential, as well as alterations in cytochrome c levels and intracellular calcium concentrations in human leukemia-derived cell lines (CCRF-CEM, K562 and its doxorubicin-resistant derivative K562/DOX) and normal peripheral blood-derived mononuclear cells (PBMC).

Results

We found that DOX-TRF can induce apoptosis in all leukemia-derived cell lines tested, which was associated with morphological changes and decreases in mitochondrial membrane potential. In comparison to free DOX treated cells, we observed a time-dependency between a higher level of ROS generation and a higher drop in mitochondrial membrane potential, particularly in the doxorubicin-resistant cell line. In addition, we found that the apoptotic cell death induced by DOX-TRF was directly associated with a release of cytochrome c from the mitochondria and an increase in intracellular calcium level in all human leukemia-derived cell lines tested.

Conclusions

Our data indicate that DOX-TRF is considerably more cytotoxic to human leukemia cells than free DOX. In addition, we show that DOX-TRF can effectively produce free radicals, which are directly involved in apoptosis induction.

     

<Emphasis Type="Italic">Hdac7</Emphasis> promotes lung tumorigenesis by inhibiting Stat3 activation

Background

Lung cancer is the leading cause of cancer death worldwide. However, the molecular mechanisms underlying lung cancer development have not been fully understood. The functions of histone deacetylases (HDACs), a class of total eighteen proteins (HDAC1–11 and SIRT1–7 in mammals) that deacetylate histones and non-histone proteins, in cancers are largely unknown.

Methods

Hdac7 ^+/?/K-Ras mice and HDAC7-depleted human lung cancer cell lines were used as models for studying the function of Hdac7 gene in lung cancer. Kaplan-Meier survival analysis was performed to explore the relationship between HDAC7 expression and prognosis of human lung cancers. Recombinant lentivirus-mediated in vivo gene expression or knockdown, Western blotting, and pull-down assay were applied to investigate the underlying molecular mechanism by which Hdac7 promotes lung tumorigenesis.

Results

The number and burden of lung tumor were dramatically reduced in Hdac7 ^+/?/K-Ras mice compared to control K-Ras mice. Also, in Hdac7 ^+/?/K-Ras mice, cell proliferation was significantly inhibited and apoptosis in lung tumors was greatly enhanced. Similarly, cell proliferation and anchorage-independent growth of human lung cancer cell lines expressing shHDAC7 were also significantly suppressed and apoptosis was dramatically elevated respectively. Mechanistic study revealed that Hdac7 mutation in mouse lung tumors or HDAC7 depletion in human tumor cell lines resulted in significantly enhanced acetylation and tyrosine-phosphorylation of Stat3 and HDAC7 protein directly interacted with and deacetylateed STAT3. The Hdac7 mutant-mediated inhibitory effects on lung tumorigenesis in mice and cell proliferation/soft agar colony formation of human lung cancer cell lines were respectively reversed by expressing dnStat3. Finally, the high HDAC7 mRNA level was found to be correlated with poor prognosis of human lung cancer patients.

Conclusion

Our study suggests that Hdac7 promotes lung tumorigenesis by inhibiting Stat3 activation via deacetylating Stat3 and may shed a light on the design of new therapeutic strategies for human lung cancer.

     

Leptin promotes the migration and invasion of breast cancer cells by upregulating <Emphasis Type="Italic">ACAT2</Emphasis>

Background

Previously, it has been shown that obesity may be considered as a risk factor for breast cancer in postmenopausal women. Leptin, a hormone whose level is elevated in obesity, has been suggested to be involved in the development of breast cancer, and univariate survival analyses have shown that over-expression of ACAT2, an enzyme that is involved in the production of cholesteryl esters, may be associated with a poor prognosis. Here, we aimed to investigate the effect of leptin on the proliferation, migration and invasion of breast cancer cells, as well as to elucidate its underlying mode of action.

Methods

Gene expression changes in leptin treated breast cancer-derived MCF-7, T47D and BT474 cells were assessed using PCR array, qRT-PCR and Western blot analyses. The expression patterns of Ob-R (leptin receptor) and ACAT2 in breast cancer cells and primary breast cancer tissue samples were analyzed using immunofluorescence and immunohistochemistry, respectively. Leptin-induced proliferation of breast cancer cells was assessed using a CCK8 assay, and scratch wound and Transwell assays were used to assess breast cancer cell invasion and migration.

Results

We found that, among the genes tested, ACAT2 expression exhibited the most significant changes in the leptin treated cells. In addition, we found that inhibition of ACAT2 expression using pyripyropene A (PPPA) or siRNA-mediated gene silencing significantly decreased leptin-induced proliferation, migration and invasion of MCF-7 and T47D cells. Subsequent Western blot analyses strongly indicated that the PI3K/AKT/SREBP2 signaling pathway was involved in leptin-induced ACAT2 upregulation in both MCF-7 and T47D cells. Finally, through the analysis of primary breast cancer tissue samples we found that ACAT2 may affect cancer progression through activation of the Ob-R.

Conclusions

Our data indicate that leptin may enhance the proliferation, migration and invasion of breast cancer cells via ACAT2 up-regulation through the PI3K/AKT/SREBP2 signaling pathway. Therefore, the leptin/ACAT2 axis may represent an attractive therapeutic target for breast cancer, particularly in postmenopausal and/or obese women.

     

ATM-depletion in breast cancer cells confers sensitivity to PARP inhibition

Background

Mutations in the DNA damage response (DDR) factors, breast cancer 1 (BRCA1) and BRCA2, sensitize tumor cells to poly(ADP-ribose) polymerase (PARP) inhibitors. The ataxia telangiectasia mutated (ATM) kinase is a key DDR protein whose heterozygous germline mutation is a moderate–risk factor for developing breast cancer. In this study, we examined whether ATM inactivation in breast cancer cell lines confers sensitivity to PARP inhibitors.

Methods

Wild-type BRCA1/2 breast cancer cells (i.e., MCF-7 and ZR-75-1 lines) were genetically manipulated to downregulate ATM expression then assayed for cytostaticity/cytotoxicity upon treatment with PARP inhibitors, olaparib and iniparib.

Results

When ATM-depleted cells and their relative controls were treated with olaparib (a competitive PARP-1/2 inhibitor) and iniparib (a molecule originally described as a covalent PARP-1 inhibitor) a different response to the two compounds was observed. ATM-depletion sensitized both MCF-7 and ZR-75-1 cells to olaparib-treatment, as assessed by short and long survival assays and cell cycle profiles. In contrast, iniparib induced only a mild, ATM-dependent cytostatic effect in MCF-7 cells whereas ZR-75-1 cells were sensitive to this drug, independently of ATM inactivation. These latest results might be explained by recent observations indicating that iniparib acts with mechanisms other than PARP inhibition.

Conclusions

These data indicate that ATM-depletion can sensitize breast cancer cells to PARP inhibition, suggesting a potential in the treatment of breast cancers low in ATM protein expression/activity, such as those arising in mutant ATM heterozygous carriers.

     

Genetic mutation analysis of the malignant transformation of sinonasal inverted papilloma by targeted amplicon sequencing

Background

The mechanism underlying the malignant transformation of inverted papilloma (IP) has not yet been elucidated.

Methods

To clarify the genes responsible for the malignant transformation, we analyzed 10 cases of IP, 8 of IP with dysplasia, and 11 of squamous cell carcinoma (SCC) by targeted amplicon sequencing.

Results

The number of mutant genes increased in the order of IP?<?dysplasia?<?SCC. Significant differences were observed in the mutation rates of three genes (KRAS, APC and STK11) in particular. TP53 was altered frequently in each group and might be involved in malignant transformation based on to the site of the mutation. A comparison of the genetic variants by region of IP tissue among patients with IP alone, and those with dysplasia or SCC revealed significant differences in the mutation rate of the KRAS gene.

Conclusion

Identification of genetic mutations in KRAS is effective for predicting the malignant transformation of IP.

     

Cancers et environnement : explorer les comportements de recherche et les sources d’information des personnes atteintes et non atteintes d’un cancer

Aim

To explore information-seeking behaviors on links between cancers and environment.

Method

Focus groups and individual semi-structured interviews realized, respectively, with individuals without and with personal cancer experience.

Results

The majority of respondents reported informationscanning behaviors. Only half cancer patients searched for information regarding the links between cancers and environment.

Conclusion

Little information is sought on links between cancers and environment.

     

Assessing the relationship between fear of cancer recurrence and health care utilization in early-stage breast cancer survivors

Purpose

The purpose of this study was to determine whether fear of cancer recurrence (FCR) is associated with greater health care utilization (HCU) in early-stage breast cancer survivors.

Methods

Three hundred early-stage breast cancer survivors diagnosed within the past 7 years reported on FCR as well as calls and visits to oncology providers and primary care providers during the preceding 3 months. Participants also reported on use of mental health services and psychotropic medications since diagnosis. Structural equation modeling was used to create a latent FCR factor and evaluate this factor as a predictor of various HCU outcomes controlling for age at diagnosis, years since diagnosis, generalized anxiety, objective risk of recurrence, and number of comorbidities.

Results

FCR predicted more visits to both oncology providers (RR?=?1.53, p?=?.002) and primary care providers (RR?=?1.31, p?=?.013), as well as more phone calls to oncology providers (RR?=?2.08, p?=?.007). FCR was not a significant predictor of phone calls to primary care providers (RR?=?1.39, p?=?.054), utilization of mental health treatment (OR?=?1.27, p?=?.362), or use of psychotropic medications (OR?=?1.37, p?=?.178).

Conclusions

FCR was associated with increases in some types of HCU, which may reflect excessive medical reassurance-seeking and lead to unnecessary medical costs.

Implications for Cancer Survivors

FCR is a serious concern that warrants greater attention to reduce distress-related health care utilization. Utilization of mental health services to address FCR may represent higher-value health care.

     

Nuclear β-catenin and CD44 upregulation characterize invasive cell populations in non-aggressive MCF-7 breast cancer cells

Background

In breast cancer cells, the metastatic cell state is strongly correlated to epithelial-to-mesenchymal transition (EMT) and the CD44⁺/CD24^- stem cell phenotype. However, the MCF-7 cell line, which has a luminal epithelial-like phenotype and lacks a CD44⁺/CD24^- subpopulation, has rare cell populations with higher Matrigel invasive ability. Thus, what are the potentially important differences between invasive and non-invasive breast cancer cells, and are the differences related to EMT or CD44/CD24 expression?

Methods

Throughout the sequential selection process using Matrigel, we obtained MCF-7-14 cells of opposite migratory and invasive capabilities from MCF-7 cells. Comparative analysis of epithelial and mesenchymal marker expression was performed between parental MCF-7, selected MCF-7-14, and aggressive mesenchymal MDA-MB-231 cells. Furthermore, using microarray expression profiles of these cells, we selected differentially expressed genes for their invasive potential, and performed pathway and network analysis to identify a set of interesting genes, which were evaluated by RT-PCR, flow cytometry or function-blocking antibody treatment.

Results

MCF-7-14 cells had enhanced migratory and invasive ability compared with MCF-7 cells. Although MCF-7-14 cells, similar to MCF-7 cells, expressed E-cadherin but neither vimentin nor fibronectin, β-catenin was expressed not only on the cell membrane but also in the nucleus. Furthermore, using gene expression profiles of MCF-7, MCF-7-14 and MDA-MB-231 cells, we demonstrated that MCF-7-14 cells have alterations in signaling pathways regulating cell migration and identified a set of genes (PIK3R1, SOCS2, BMP7, CD44 and CD24). Interestingly, MCF-7-14 and its invasive clone CL6 cells displayed increased CD44 expression and downregulated CD24 expression compared with MCF-7 cells. Anti-CD44 antibody treatment significantly decreased cell migration and invasion in both MCF-7-14 and MCF-7-14 CL6 cells as well as MDA-MB-231 cells.

Conclusions

MCF-7-14 cells are a novel model for breast cancer metastasis without requiring constitutive EMT and are categorized as a "metastable phenotype", which can be distinguished from both epithelial and mesenchymal cells. The alterations and characteristics of MCF-7-14 cells, especially nuclear β-catenin and CD44 upregulation, may characterize invasive cell populations in breast cancer.

     

Clinical and biological roles of Kelch-like family member 7 in breast cancer: a marker of poor prognosis

Background

The functions of many proteins are tightly regulated with a complex array of cellular functions including ubiquitination. In cancer cells, aberrant ubiquitination may promote the activity of oncogenic pathways with subsequent tumour progression. Kelch-like family member 7 (KLHL7) is involved in the regulation of ubiquitination and may play a role in breast cancer (BC). Present study aims to evaluate the biological and clinical usefulness of KLHL7 in BC utilising large well-characterised cohorts with long-term follow-up.

Methods

The relationships between KLHL7 gene copy number alteration (CNA) and mRNA expression and clinicopathological variables and clinical outcomes were evaluated in 1980 patients from the METABRIC BC cohort. Prognostic significance of KLHL7 mRNA was validated using the Breast Cancer Gene-Expression Miner v4.0 datasets (n?=?5206). KLHL7 protein expression was assessed using immunohistochemistry in a large annotated series of early-stage BC (n?=?917) with long-term follow-up.

Results

KLHL7 CNA was significantly correlated with its mRNA expression. KLHL7 mRNA expression was higher in luminal B and basal-like molecular subtypes and in higher grade tumours. Increased KLHL7 protein expression was significantly correlated with features of aggressive phenotype including lymphovascular invasion, high histological grade, hormonal receptor negativity, high PIK3CA and p53 expression. Outcome analysis showed that high KLHL7 expression is an independent predictor of shorter survival (p?=?0.0011).

Conclusions

KLHL7 appears to play an important role in BC progression. High KLHL7 protein expression identified a subgroup of BC with aggressive behaviour and provided independent prognostic information.

     

Germline promoter hypermethylation in <Emphasis Type="Italic">BRCA1</Emphasis> and <Emphasis Type="Italic">BRCA2</Emphasis> genes is not present in hereditary breast cancer patients

Purpose

Germline promoter hypermethylation of BRCA1 and BRCA2 genes is an alternative event of gene silencing that has not been widely investigated in hereditary breast and ovarian cancer (HBOC) syndrome.

Methods

We analyzed germline BRCA promoter hypermethylation in HBOC patients with and without BRCA mutations and control subjects, using a recently developed BRCA methylation-specific multiplex ligation-dependent probe amplification (MS-MLPA) assay.

Results

Neither the patients tested nor the control subjects showed germline hypermethylation of the BRCA1 and BRCA2 promoter regions analyzed.

Conclusions

Despite the results achieved at somatic levels by other researchers, these were not confirmed in our study at the germline level. Our results show the need to establish more predictive CpG sites in the BRCA promoter regions to optimize the MS-MLPA assayfor the detection of germline hypermethylation as an effective pre-screening tool for whole-BRCA genetic analysis in HBOC, because we can not rule out the existence of germline promoter hypermethylation in BRCA.

     

Survivorship care plans and adherence to lifestyle recommendations among breast cancer survivors

Purpose

The effectiveness of survivorship care plans has not been widely tested. We evaluated whether a one-time brief lifestyle consultation as part of a broader survivorship care plan was effective at changing diet and lifestyle patterns.

Methods

A diverse sample of women with stage 0-III breast cancer were randomized to control or intervention groups within 6 weeks of completing adjuvant treatment. Both groups received the National Cancer Institute publication, “Facing Forward: Life after Cancer Treatment.” The intervention group also met with a nurse (1 h) and a nutritionist (1 h) to receive personalized lifestyle recommendations based upon national guidelines. Diet, lifestyle, and perceived health were assessed at baseline, 3 and 6 months. Linear regression analyses evaluated the effects of the intervention adjusted for covariates.

Results

A total of 126 women completed the study (60 control/66 intervention, 61 Hispanic/65 non-Hispanic). At 3 months, the intervention group reported greater knowledge of a healthy diet (P?=?0.047), importance of physical activity (P?=?0.03), and appropriate use of dietary supplements (P?=?0.006) and reported lower frequency of alcohol drinking (P?=?0.03) than controls. At 6 months, only greater knowledge of a healthy diet (P?=?0.01) persisted. The intervention was more effective among non-Hispanics than Hispanics on improving attitude towards healthy eating (P?=?0.03) and frequency of physical activity (P?=?0.006).

Conclusions

The intervention changed lifestyle behaviors and knowledge in the short-term, but the benefits did not persist.

Implications for Cancer Survivors

Culturally competent long-term behavioral interventions should be tested beyond the survivorship care plan to facilitate long-term behavior change among breast cancer survivors.

     

Short stature in retinoblastoma survivors: a cross-sectional study of 138 patients

Purpose

Short stature has been reported in pediatric cancer survivors. Data on retinoblastoma survivors are limited. We conducted a cross-sectional study to assess the height in retinoblastoma survivors.

Method

The recorded height was compared with median height for age and sex as per the Indian Academy of Pediatrics. Z-score less than ?2 was considered short statured.

Result

Thirty percent of the survivors were short statured. The mean height was shorter than the mean 50th percentile height (119.7 ± 14.8 vs 128.7 ± 15 cm, p < 0.001). Previous chemotherapy showed a trend toward association (p = 0.09).

Conclusion

Short stature affects a significant number of retinoblastoma survivors.

     

Pentoxifylline during steroid window phase at induction to remission increases apoptosis in childhood with acute lymphoblastic leukemia

Purpose

Pentoxifylline (PTX) has been shown to increase chemotherapy-induced apoptosis. A clinical trial was developed to evaluate the effect of the addition of PTX to the induction steroid window phase in children with acute lymphoblastic leukemia (ALL).

Methods

Thirty-two children were enrolled on this study. Children with a new diagnosis of ALL were randomly assigned to receive prednisone (PRD) 40 mg/m²/day only during the 7-day treatment pre-phase (PRD group, 11 patients) or to receive PRD with PTX (10 mg/kg/day) (PTX group, 11 patients); the control group included children with normal bone marrow (10 patients). Bone marrow aspiration (BMA) was performed at diagnosis (day ?7) in all groups, and at day 0 (end of PRD window) for patients with ALL (PRD and PTX groups). Apoptosis was evaluated by flow cytometry (FC) using Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) stains. Statistical analysis was performed using the Mann–Whitney U test.

Results

Apoptotic index at day ?7 was similar in all groups. However, at day 0 post-treatment, apoptosis was significantly higher in the PTX group than in the PRD group (p < 0.001). There were no serious adverse effects associated with PTX.

Conclusions

PTX potentiates blast apoptosis induced by PRD in children with ALL during steroid window phase.