MDR1 not CYP3A4 gene expression is the predominant mechanism of innate drug resistance in pediatric soft tissue sarcoma patients

Heparin and Heparin-Based Drug Delivery Systems: Pleiotropic Molecular Effects at Multiple Drug Resistance of Osteosarcoma and Immune Cells

One of the main problems of modern health care is the growing number of oncological diseases both in the elderly and young population. Inadequately effective chemotherapy, which remains the main method of cancer control, is largely associated with the emergence of multidrug resistance in tumor cells. The search for new solutions to overcome the resistance of malignant cells to pharmacological agents is being actively pursued. Another serious problem is immunosuppression caused both by the tumor cells themselves and by antitumor drugs. Of great interest in this context is heparin, a biomolecule belonging to the class of glycosaminoglycans and possessing a broad spectrum of biological activity, including immunomodulatory and antitumor properties. In the context of the rapid development of the new field of “osteoimmunology,” which focuses on the collaboration of bone and immune cells, heparin and delivery systems based on it may be of intriguing importance for the oncotherapy of malignant bone tumors. Osteosarcoma is a rare but highly aggressive, chemoresistant malignant tumor that affects young adults and is characterized by constant recurrence and metastasis. This review describes the direct and immune-mediated regulatory effects of heparin and drug delivery systems based on it on the molecular mechanisms of (multiple) drug resistance in (onco) pathological conditions of bone tissue, especially osteosarcoma.

Expression of Cytochrome P450 Enzymes in Pediatric Non-Rhabdomyosarcoma Soft Tissue Sarcomas: Possible Role in Carcinogenesis and Treatment Response

The 5-year relative survival rate estimate of treated patients with non-rhabdomyosarcoma soft tissue sarcomas (NRSTS) is ∼50% since they generally present with tumor progression, relapse, metastasis, and/or chemoresistance. The expression of cytochrome P450 (CYP) enzymes in malignancies can affect the pharmacology of drugs commonly used in chemotherapy or confer susceptibility to development of chemical carcinogenesis; in addition, their specific tumor expression can be used as a therapeutic target. Using qPCR and Western blot assays, the expression of CYP1B1, CYP2E1, CYP3A4, and CYP3A5 were analyzed in a cohort of tumor tissue paired with non-malignant adjacent tissue of patients with NRSTS. The mRNA and protein expression of CYP1B1, CYP2E1, and CYP3A4 were significantly increased in tumor tissue. We propose that the expression of these isoforms is related to carcinogenesis and chemoresistance frequently observed in these neoplasms.

Pharmacogenomics of soft tissue sarcomas: New horizons to understand efficacy and toxicity

Clinical responses to anticancer therapies in advanced soft tissue sarcoma (STS) are unfortunately limited to a small subset of patients. Much of the inter-individual variability in treatment efficacy and risk of toxicities is as result of polymorphisms in genes encoding proteins involved in drug pharmacokinetics and pharmacodynamics. Therefore, the detection of pharmacogenomics (PGx) biomarkers that might predict drug response and toxicity can be useful to explain the genetic basis for the differences in treatment efficacy and toxicity among STS patients. PGx markers are frequently located in transporters, drug-metabolizing enzyme genes, drug targets, or HLA alleles. Along this line, genetic variability harbouring in the germline genome of the patients can influence systemic pharmacokinetics and pharmacodynamics of the treatments, acting as predictive biomarkers for drug-induced toxicity and treatment efficacy. By linking drug activity to the functional complexity of cancer genomes, also systematic pharmacogenomic profiling in cancer cell lines and primary STS samples represents area of active investigation that could eventually lead to enhanced efficacy and offer a powerful biomarker discovery platform to optimize current treatments and improve the knowledge about the individual's drug response in STS patients into the clinical practice.

Resveratrol reduces drug resistance of SCLC cells by suppressing the inflammatory microenvironment and the STAT3/VEGF pathway

DNA‐damaging agents, such as doxorubicin (Adriamycin), are widely used for the treatment of small cell lung cancer (SCLC). However, drug resistance is one of the major challenges for treatment of SCLC. Herein, we investigated the mechanisms underlying drug resistance in SCLC cells and the effects of resveratrol (Res) on drug resistance. We report that Adriamycin treatment of H69AR (multidrug resistance phenotype) cells resulted in a lower rate of growth inhibition, up‐regulation of MRP1 and P‐glycoprotein (P‐gp), and higher P‐gp activity as compared with susceptible H69 cells treated with Adriamycin. Moreover, the signal transducer and activator of transcription 3/vascular endothelial growth factor (STAT3/VEGF) pathway was overactivated in H69AR cells, especially after interleukin‐23 treatment. The inflammatory microenvironment promoted the drug resistance of H69AR cells by activating the STAT3/VEGF pathway. The addition of Res suppressed the expression levels of inflammatory mediators, inhibited the STAT3/VEGF pathway, impeded P‐gp activity, and decreased the drug resistance of H69AR cells. H69AR cells exhibited Adriamycin resistance through activation of the STAT3/VEGF pathway, and Res ameliorated the inflammatory microenvironment to suppress the STAT3/VEGF pathway to reduce drug resistance. Our results suggest that Res may have therapeutic potential for SCLC treatment.

Academic paediatric surgery and work-life balance: Insights from Mexico

Academic pediatric surgery in Mexico has many challenges and opportunities. Work life balance, health service delivery and committements to our many students and residents must be tailored to goals and aspirations respecting talent at every opportunity when we encounter it. This article offers a perspective on the landscape and how we can shape the future in our nation to embrace new leadership in academic pediatric surgery.

The free amino acid profiles and metabolic biomarkers of predicting the chemotherapeutic response in advanced sarcoma patients

PURPOSE

Metabolomics is an emerging field in cancer research. Plasma free amino acid profiles (PFAAs) have shown different features in various cancers, but the characteristic in advanced sarcoma remains unclear. We aimed to uncover the specific PFAAs in advanced sarcoma and to find the relationship between the altering of PFAAs and response to chemotherapy.

PATIENTS AND METHODS

We analyzed the differences in PFAAs between 23 sarcoma patients and 30 healthy subjects basing on liquid chromatography-tandem mass spectrometry (LC-MS/MS). Then, we compared the dynamics of PFAAs after chemotherapy between improvement group and deterioration group.

RESULTS

We identified seven biological differential amino acids and four pathways which were perturbed in the sarcoma patients compared with healthy subjects. After one cycle chemotherapy, the levels of γ-aminobutyric acid (GABA) and carnosine (Car) decreased significantly in the improvement group but not in deterioration group. The levels of α-aminobutyric acid (Abu) increased significantly in the deterioration group but not in the improvement group.

CONCLUSION

Our study suggests the potential specific PFAAs in sarcoma patients. The unusual amino acids and metabolic pathways may provide ideas for clinical drugs targeting therapy. Three amino acids including Car, GABA and Abu may be metabolic biomarkers playing a role in dynamic monitoring of the therapeutic effect.