Imatinib revives the therapeutic potential of metformin on ewing sarcoma by attenuating tumor hypoxic response and inhibiting convergent signaling pathways

Hypoxia and HIFs in Ewing sarcoma: new perspectives on a multi-facetted relationship

Hypoxia develops during the growth of solid tumors and influences tumoral activity in multiple ways. Low oxygen tension is also present in the bone microenvironment where Ewing sarcoma (EwS) - a highly aggressive pediatric cancer - mainly arises. Hypoxia inducible factor 1 subunit alpha (HIF-1-a) is the principal molecular mediator of the hypoxic response in cancer whereas EWSR1::FLI1 constitutes the oncogenic driver of EwS. Interaction of the two proteins has been shown in EwS. Although a growing body of studies investigated hypoxia and HIFs in EwS, their precise role for EwS pathophysiology is not clarified to date. This review summarizes and structures recent findings demonstrating that hypoxia and HIFs play a role in EwS at multiple levels. We propose to view hypoxia and HIFs as independent protagonists in the story of EwS and give a perspective on their potential clinical relevance as prognostic markers and therapeutic targets in EwS treatment.

Genetic Alterations and Deregulation of Hippo Pathway as a Pathogenetic Mechanism in Bone and Soft Tissue Sarcoma

The Hippo pathway is an evolutionarily conserved modulator of developmental biology with a key role in tissue and organ size regulation under homeostatic conditions. Like other signaling pathways with a significant role in embryonic development, the deregulation of Hippo signaling contributes to oncogenesis. Central to the Hippo pathway is a conserved cascade of adaptor proteins and inhibitory kinases that converge and regulate the activity of the oncoproteins YAP and TAZ, the final transducers of the pathway. Elevated levels and aberrant activation of YAP and TAZ have been described in many cancers. Though most of the studies describe their pervasive activation in epithelial neoplasms, there is increasing evidence pointing out its relevance in mesenchymal malignancies as well. Interestingly, somatic or germline mutations in genes of the Hippo pathway are scarce compared to other signaling pathways that are frequently disrupted in cancer. However, in the case of sarcomas, several examples of genetic alteration of Hippo members, including gene fusions, have been described during the last few years. Here, we review the current knowledge of Hippo pathway implication in sarcoma, describing mechanistic hints recently reported in specific histological entities and how these alterations represent an opportunity for targeted therapy in this heterogeneous group of neoplasm.

Is Metformin Use Associated with Prolonged Overall Survival in Patients with Soft Tissue Sarcoma? A SEER-Medicare Study

BACKGROUND

Metformin, an oral drug used to treat patients with diabetes, has been associated with prolonged survival in patients with various visceral carcinomas. Although the exact mechanisms are unknown, preclinical translational studies demonstrate that metformin may impair tumor cellular metabolism, alter matrix turnover, and suppress oncogenic signaling pathways. Currently used chemotherapeutic agents have not been very successful in the adjuvant setting or for treating patients with metastatic sarcomas. We wanted to know whether metformin might be associated with improved survival in patients with a soft tissue sarcoma.

QUESTIONS/PURPOSES

In patients treated for a soft tissue sarcoma, we asked: (1) Is there an association between metformin use and longer survival? (2) How does this association differ, if at all, among patients with and without the diagnosis of diabetes?

METHODS

The Surveillance, Epidemiology, and End Results-Medicare (SEER-Medicare) database was used to identify patients with a diagnosis of soft tissue sarcoma from 2007 to 2016. Concomitant medication use was identified using National Drug Codes using the Medicare Part D event files. This database was chosen because of the large number of captured sarcoma patients, availability of tumor characteristics, and longitudinal linkage of Medicare data. A total of 14,650 patients were screened for inclusion. Patients with multiple malignancies, diagnosis at autopsy, or discrepant linkage to the Medicare database were excluded. Overall, 4606 patients were eligible for the study: 598 patients taking metformin and 4008 patients not taking metformin. A hazard of mortality (hazard ratio) was analyzed comparing patients taking metformin with those patient groups not taking metformin and expressed in terms of a 95% confidence interval. Cox regression analysis was used to control for patient-specific, disease-specific, and treatment-specific covariates.

RESULTS

Having adjusted for disease-, treatment-, and patient-specific characteristics, patients taking metformin experienced prolonged survival compared with all patients not taking metformin (HR 0.76 [95% CI 0.66 to 0.87]). Associated prolonged survival was also seen when patients taking metformin were compared with those patients not on metformin irrespective of a diabetes diagnosis (HR 0.79 [95% CI 0.66 to 0.94] compared with patients with a diagnosis of diabetes and HR 0.77 [95% CI 0.67 to 0.89] compared with patients who did not have a diagnosis of diabetes).

CONCLUSION

Without suggesting causation, we found that even after controlling for confounding variables such as Charlson comorbidity index, tumor grade, size, stage, and surgical/radiation treatment modalities, there was an association between metformin use and increased survival in patients with soft tissue sarcoma. When considered separately, this association persisted in patients not on metformin with and without a diabetes diagnosis. Although metformin is not normally prescribed to patients who do not have a diabetes diagnosis, these data support further study, and if these findings are substantiated, it might lead to the performance of multicenter, prospective clinical trials about the use of metformin as an adjuvant therapy for the treatment of soft tissue sarcoma in patients with and without a preexisting diabetes diagnosis.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Discovery of Potent and Orally Bioavailable Platelet-Derived Growth Factor Receptor (PDGFR) Inhibitors for the Treatment of Osteosarcoma

Platelet-derived growth factor receptors (PDGFRs) are now considered promising targets for the treatment of osteosarcoma. Herein, the design, synthesis, and structure-activity relationships (SAR) of novel pyrimidine-2,4-diamine derivatives that selectively inhibit PDGFRα/β kinases have been studied. The screening cascades revealed that 7m was the preferred compound among these derivatives, with IC₅₀ values of 2.4 and 0.9 nM for PDGFRα and PDGFRβ, respectively. Moreover, the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) experiment revealed that 7m has a substantial cytotoxic effect against all osteosarcoma cancer cell lines; 7m also displayed robust antitumor effects and low toxicity in a xenograft model. Additionally, 7m showed excellent bioavailability (F = 62.9%), suitable half-life (T_1/2 = 2.12 h), satisfactory metabolic stability, and weak CYP isoform inhibitory activity, suggesting that 7m is a potential drug candidate for PDGFR-driven osteosarcoma.

Converging multi-modality datasets to build efficient drug repositioning pipelines against Alzheimer's disease and related dementias

Alzheimer's disease and related dementias (AD/ADRD) affects more than 50 million people worldwide but there is no clear therapeutic option affordable for the general patient population. Recently, drug repositioning studies featuring collaborations between academic institutes, medical centers, and hospitals are generating novel therapeutics candidates against these devastating diseases and filling in an important area for healthcare that is poorly represented by pharmaceutical companies. Such drug repositioning studies converge expertise from bioinformatics, chemical informatics, medical informatics, artificial intelligence, high throughput and high-content screening and systems biology. They also take advantage of multi-scale, multi-modality datasets, ranging from transcriptomic and proteomic data, electronical medical records, and medical imaging to social media information of patient behaviors and emotions and epidemiology profiles of disease populations, in order to gain comprehensive understanding of disease mechanisms and drug effects. We proposed a recursive drug repositioning paradigm involving the iteration of three processing steps of modeling, prediction, and validation to identify known drugs and bioactive compounds for AD/ADRD. This recursive paradigm has the potential of quickly obtaining a panel of robust novel drug candidates for AD/ADRD and gaining in-depth understanding of disease mechanisms from those repositioned drug candidates, subsequently improving the success rate of predicting novel hits.

Artificial intelligence unifies knowledge and actions in drug repositioning

Drug repositioning aims to reuse existing drugs, shelved drugs, or drug candidates that failed clinical trials for other medical indications. Its attraction is sprung from the reduction in risk associated with safety testing of new medications and the time to get a known drug into the clinics. Artificial Intelligence (AI) has been recently pursued to speed up drug repositioning and discovery. The essence of AI in drug repositioning is to unify the knowledge and actions, i.e. incorporating real-world and experimental data to map out the best way forward to identify effective therapeutics against a disease. In this review, we share positive expectations for the evolution of AI and drug repositioning and summarize the role of AI in several methods of drug repositioning.

Melatonin Induces Apoptosis and Modulates Cyclin Expression and MAPK Phosphorylation in Pancreatic Stellate Cells Subjected to Hypoxia

In certain diseases of the pancreas, pancreatic stellate cells form an important part of fibrosis and are critical for the development of cancer cells. A hypoxic condition develops within the tumor, to which pancreatic stellate cells adapt and are able to proliferate. The consequence is the growth of the tumor. Melatonin, the product of the pineal gland, is gaining attention as an agent with therapeutic potential against pancreatic cancers. Its actions on tumor cells lead, in general, to a reduction in cell viability and proliferation. However, its effects on pancreatic stellate cells subjected to hypoxia are less known. In this study, we evaluated the actions of pharmacological concentrations of melatonin (1 mM–1 µM) on pancreatic stellate cells subjected to hypoxia. The results show that melatonin induced a decrease in cell viability at the highest concentrations tested. Similarly, the incorporation of BrdU into DNA was diminished by melatonin. The expression of cyclins A and D also was decreased in the presence of melatonin. Upon treatment of cells with melatonin, increases in the expression of major markers of ER stress, namely BIP, phospho-eIF2α and ATF-4, were detected. Modulation of apoptosis was noticed as an increase in caspase-3 activation. In addition, changes in the phosphorylated state of p44/42, p38 and JNK MAPKs were detected in cells treated with melatonin. A slight decrease in the content of α-smooth muscle actin was detected in cells treated with melatonin. Finally, treatment of cells with melatonin decreased the expression of matrix metalloproteinases 2, 3, 9 and 13. Our observations suggest that melatonin, at pharmacological concentrations, diminishes the proliferation of pancreatic stellate cells subjected to hypoxia through modulation of cell cycle, apoptosis and the activation of crucial MAPKs. Cellular responses might involve certain ER stress regulator proteins. In view of the results, melatonin could be taken into consideration as a potential therapeutic agent for pancreatic fibrosis.

Melatonin Modulates the Antioxidant Defenses and the Expression of Proinflammatory Mediators in Pancreatic Stellate Cells Subjected to Hypoxia

Pancreatic stellate cells (PSC) play a major role in the formation of fibrotic tissue in pancreatic tumors. On its side, melatonin is a putative therapeutic agent for pancreatic cancer and inflammation. In this work, the actions of melatonin on PSC subjected to hypoxia were evaluated. Reactive oxygen species (ROS) generation reduced (GSH) and oxidized (GSSG) levels of glutathione, and protein and lipid oxidation were analyzed. The phosphorylation of nuclear factor erythroid 2-related factor (Nrf2), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB), and the regulatory protein nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-alpha (IκBα) was studied. The expression of Nrf2-regulated antioxidant enzymes, superoxide dismutase (SOD) enzymes, cyclooxygenase 2 (COX-2), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were also studied. Total antioxidant capacity (TAC) was assayed. Finally, cell viability was studied. Under hypoxia and in the presence of melatonin generation of ROS was observed. No increases in the oxidation of proteins or lipids were detected. The phosphorylation of Nrf2 and the expression of the antioxidant enzymes catalytic subunit of glutamate-cysteine ligase, catalase, NAD(P)H-quinone oxidoreductase 1, heme oxygenase-1, SOD1, and of SOD2 were augmented. The TAC was increased. Protein kinase C was involved in the effects of melatonin. Melatonin decreased the GSH/GSSG ratio at the highest concentration tested. Cell viability dropped in the presence of melatonin. Finally, melatonin diminished the phosphorylation of NF-kB and the expression of COX-2, IL-6, and TNF-α. Our results indicate that melatonin, at pharmacological concentrations, modulates the red-ox state, viability, and the expression of proinflammatory mediators in PSC subjected to hypoxia.

Comprehensive Analysis of Aerobic Exercise-Related Genes Identifies CDCA4 That Promotes the Progression of Osteosarcoma

Background

Exercise has a positive impact on patients with osteosarcoma, improving function, reducing disability, maintaining independence and quality of life. Exercise may also directly affect the effectiveness of cancer treatment. Cell division cycle-associated protein 4 (CDCA4) is reported to function importantly during numerous human cancers development. Nevertheless, the details toward CDCA4 function are still to be investigated.

Methods

This study comprehensively analyzed the GSE74194 database and obtained aerobic exercise-related genes. Protein-protein interaction network (PPI) and Gene Ontology (GO) analysis were performed on the differentially expressed genes (DEGs). Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and tumor genome atlas (TCGA) data mining were applied to measure aerobic exercise-related gene CDCA4 level in osteosarcoma tissue. We conducted lots of functional experiments to uncover CDCA4 function and its corresponding mechanism in osteosarcoma.

Results

We screened a total of 547 DEGs related to aerobic exercise, of which 373 were up-regulated and 174 were down-regulated. PPI analysis revealed 90 genes that might play key roles. GO analysis showed that aerobic exercise-related DEGs were significantly enriched during the mitotic cell cycle, cell division, mitotic nuclear division and sister chromatid segregation, nuclear division, microtubule cytoskeleton organization involved protein, microtubule-based process, spindle organization, G2/M transition of mitotic cell cycle. Our results indicated that CDCA4 was increased in osteosarcoma tissues and cell lines, and its level had association with high mortality of osteosarcoma patients. Further studies revealed that absence of CDCA4 largely hindered osteosarcoma cancer cell proliferation, invasion, and migration.

Conclusion

Comprehensive bioinformatics analysis improves our understanding of the underlying molecular mechanisms of aerobic exercise on osteosarcoma. This provides evidence for the effect of aerobic exercise on CDCA4 expression. Our data suggested that CDCA4 could facilitate osteosarcoma development, and gave a hint that CDCA4 was a candidate target in the treatment of osteosarcoma, aerobic exercise might help the treatment and prognosis of patients with osteosarcoma.

Use of Antiangiogenic Therapies in Pediatric Solid Tumors

Cancer is an important cause of death in childhood. In recent years, scientists have made an important effort to achieve greater precision and more personalized treatments against cancer. But since only a few pediatric patients have identifiable therapeutic targets, other ways to stop the neoplastic cell proliferation and dissemination are needed. Therefore, the inhibition of general processes involved in the growth and behavior of tumors can be a relevant strategy for the development of new cancer therapies. In the case of solid tumors, one of these processes is angiogenesis, essential for tumor growth and generation of metastases. This review summarizes the results obtained with the use of antiangiogenic drugs in the main pediatric malignant solid tumors and also an overview of clinical trials currently underway. It should be noted that due to the rarity and heterogeneity of the different types of pediatric cancer, most studies on antiangiogenic drugs include only a small number of patients or isolated clinical cases, so they are not conclusive and further studies are needed.

The Role of Tyrosine Kinases as a Critical Prognostic Parameter and Its Targeted Therapies in Ewing Sarcoma

Ewing sarcoma (ES) is a rare, highly aggressive, bone, or soft tissue-associated tumor. Although this sarcoma often responds well to initial chemotherapy, 40% of the patients develop a lethal recurrence of the disease, with death recorded in 75-80% of patients with metastatic ES within 5 years, despite receiving high-dose chemotherapy. ES is genetically well-characterized, as indicated by the EWS-FLI1 fusion protein encoded as a result of chromosomal translocation in 80-90% of patients with ES, as well as in ES-related cancer cell lines. Recently, tyrosine kinases have been identified in the pathogenesis of ES. These tyrosine kinases, acting as oncoproteins, are associated with the clinical pathogenesis, metastasis, acquisition of self-renewal traits, and chemoresistance of ES, through the activation of various intracellular signaling pathways. This review describes the recent progress related to cellular and molecular functional roles of tyrosine kinases in the progression of ES.