Identification of GPC3 mutation and upregulation in a multidrug resistant osteosarcoma and its spheroids as therapeutic target

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GPC3 mutation in primary osteosarcoma becomes abundant in its metastasis.

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Mutant GPC3 is over-produced in metastatic spheroids with multidrug resistance.

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Anti-GPC3 antibody effectively commits metastatic spheroids to apoptosis.

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GPC3 would be a promising therapeutic target of osteosarcomas.

Background

Drug resistance and the lack of molecular therapeutic target are the main challenges in the management of osteosarcomas (OSs). Identification of novel genetic alteration(s) related with OS recurrence and chemotherapeutic resistance would be of scientific and clinical significance.

Methods

To identify potential genetic alterations related with OS recurrence and chemotherapeutic resistance, the biopsies of a 20-year-old male osteosarcoma patient were collected at primary site (p-OS) and from its metastatic tumor (m-OS) formed after 5 months of adjuvant chemotherapy. Both OS specimens were subjected to cancer-targeted next generation sequencing (NGS) and their cell suspensions were cultured under three-dimensional condition to establish spheroid therapeutic model. Transcript-oriented Sanger sequencing for GPC3, the detected mutated gene, was performed on RNA samples of p-OS and m-OS tissues and spheroids. The effects of anti-GPC3 antibody and its combination with cisplatin on m-OS spheroids were elucidated.

Results

NGS revealed 4 mutations (GPC3, SOX10, MDM4 and MAPK8) and 6 amplifications (MDM2, CDK4, CCND3, RUNX2, GLI1 and FRS2) in p-OS, and 3 mutations (GPC3, SOX10 and EGF) and 10 amplifications (CDK4, CCND3, MDM2, RUNX2, GLI1, FRS2, CARD11, RAC1, SLC16A7 and PMS2) in m-OS. Among those alterations, the mutation abundance of GPC3 was the highest (56.49%) in p-OS and showed 1.54 times increase in m-OS. GPC3 transcript-oriented Sanger sequencing confirmed the mutation at 1046 in Exon 4, and immunohistochemical staining showed increased GPC3 production in m-OS tissues and its spheroids. EdU cell proliferation and Calcein/PI cell viability assays revealed that of the anti-OS first line drugs (doxorubicin, cisplatin, methotrexate, ifosfamide and carboplatin), 10 μM carboplatin exerted the best inhibitory effects on the p-OS but not the m-OS spheroids. 2 μg/mL anti-GPC3 antibody effectively committed m-OS spheroids to death by itself (76.43%) or in combination with cisplatin (92.93%).

Conclusion

This study demonstrates increased abundance and up-regulated expression of mutant GPC3 in metastatic osteosarcoma and its spheroids with multidrug resistance. As GPC3-targeting therapy has been used to treat hepatocellular carcinomas and it is also effective to OS PDSs, GPC3 would be a novel prognostic parameter and therapeutic target of osteosarcomas.

The molecular feature of macrophages in tumor immune microenvironment of glioma patients

Background

Gliomas are one of the most common types of primary tumors in central nervous system. Previous studies have found that macrophages actively participate in tumor growth.

Methods

Weighted gene co-expression network analysis was used to identify meaningful macrophage-related gene genes for clustering. Pamr, SVM, and neural network were applied for validating clustering results. Somatic mutation and methylation were used for defining the features of identified clusters. Differentially expressed genes (DEGs) between the stratified groups after performing elastic regression and principal component analyses were used for the construction of MScores. The expression of macrophage-specific genes were evaluated in tumor microenvironment based on single cell sequencing analysis. A total of 2365 samples from 15 glioma datasets and 5842 pan-cancer samples were used for external validation of MScore.

Results

Macrophages were identified to be negatively associated with the survival of glioma patients. Twenty-six macrophage-specific DEGs obtained by elastic regression and PCA were highly expressed in macrophages at single-cell level. The prognostic value of MScores in glioma was validated by the active proinflammatory and metabolic profile of infiltrating microenvironment and response to immunotherapies of samples with this signature. MScores managed to stratify patient survival probabilities in 15 external glioma datasets and pan-cancer datasets, which predicted worse survival outcome. Sequencing data and immunohistochemistry of Xiangya glioma cohort confirmed the prognostic value of MScores. A prognostic model based on MScores demonstrated high accuracy rate.

Conclusion

Our findings strongly support a modulatory role of macrophages, especially M2 macrophages in glioma progression and warrants further experimental studies.

Machine Learning Identifies Clinical and Genetic Factors Associated With Anthracycline Cardiotoxicity in Pediatric Cancer Survivors

Background

Despite known clinical risk factors, predicting anthracycline cardiotoxicity remains challenging.

Objectives

This study sought to develop a clinical and genetic risk prediction model for anthracycline cardiotoxicity in childhood cancer survivors.

Methods

We performed exome sequencing in 289 childhood cancer survivors at least 3 years from anthracycline exposure. In a nested case-control design, 183 case patients with reduced left ventricular ejection fraction despite low-dose doxorubicin (≤250 mg/m²), and 106 control patients with preserved left ventricular ejection fraction despite doxorubicin >250 mg/m² were selected as extreme phenotypes. Rare/low-frequency variants were collapsed to identify genes differentially enriched for variants between case patients and control patients. The expression levels of 5 top-ranked genes were evaluated in human induced pluripotent stem cell–derived cardiomyocytes, and variant enrichment was confirmed in a replication cohort. Using random forest, a risk prediction model that included genetic and clinical predictors was developed.

Results

Thirty-one genes were differentially enriched for variants between case patients and control patients (p < 0.001). Only 42.6% case patients harbored a variant in these genes compared to 89.6% control patients (odds ratio: 0.09; 95% confidence interval: 0.04 to 0.17; p = 3.98 × 10^–15). A risk prediction model for cardiotoxicity that included clinical and genetic factors had a higher prediction accuracy and lower misclassification rate compared to the clinical-only model. In vitro inhibition of gene-associated pathways (PI3KR2, ZNF827) provided protection from cardiotoxicity in cardiomyocytes.

Conclusions

Our study identified variants in cardiac injury pathway genes that protect against cardiotoxicity and informed the development of a prediction model for delayed anthracycline cardiotoxicity, and it also provided new targets in autophagy genes for the development of cardio-protective drugs. (Preventing Cardiac Sequelae in Pediatric Cancer Survivors [PCS2]; NCT01805778)

Discovery of Genetic Variants of the Kinases That Activate Tenofovir in a Compartment-specific Manner

Tenofovir (TFV) is used in combination with other antiretroviral drugs for human immunodeficiency virus (HIV) treatment and prevention. TFV requires two phosphorylation steps to become pharmacologically active; however, the kinases that activate TFV in cells and tissues susceptible to HIV infection have yet to be identified. Peripheral blood mononuclear cells (PBMC), vaginal, and colorectal tissues were transfected with siRNA targeting nucleotide kinases, incubated with TFV, and TFV-monophosphate (TFV-MP) and TFV-diphosphate (TFV-DP) were measured using mass spectrometry–liquid chromatography. Adenylate kinase 2 (AK2) performed the first TFV phosphorylation step in PBMC, vaginal, and colorectal tissues. Interestingly, both pyruvate kinase isozymes, muscle (PKM) or liver and red blood cell (PKLR), were able to phosphorylate TFV-MP to TFV-DP in PBMC and vaginal tissue, while creatine kinase, muscle (CKM) catalyzed this conversion in colorectal tissue. In addition, next-generation sequencing of the Microbicide Trials Network MTN-001 clinical samples detected 71 previously unreported genetic variants in the genes encoding these kinases. In conclusion, our results demonstrate that TFV is activated in a compartment-specific manner. Further, genetic variants have been identified that could negatively impact TFV activation, thereby compromising TFV efficacy in HIV treatment and prevention.

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The anti-HIV drug tenofovir is activated in a tissue-specific manner.

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AK2 phosphorylates tenofovir to tenofovir-monophosphate in PBMC, vagina, and colon.

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PKM, PKLR phosphorylate tenofovir-monophosphate to diphosphate in PBMC and vagina.

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CKM phosphorylates tenofovir-monophosphate to diphosphate in colon.

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Because these enzymes are polymorphic and may be dysfunctional in some individuals, these findings suggest that tenofovir-based HIV PrEP may not be protective for all individuals.

Decoding the Molecular and Mutational Ambiguities of Gastroenteropancreatic Neuroendocrine Neoplasm Pathobiology

Gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN), considered a heterogeneous neoplasia, exhibit ill-defined pathobiology and protean symptomatology and are ubiquitous in location. They are difficult to diagnose, challenging to manage, and outcome depends on cell type, secretory product, histopathologic grading, and organ of origin. A morphologic and molecular genomic review of these lesions highlights tumor characteristics that can be used clinically, such as somatostatin-receptor expression, and confirms features that set them outside the standard neoplasia paradigm. Their unique pathobiology is useful for developing diagnostics using somatostatin-receptor targeted imaging or uptake of radiolabeled amino acids specific to secretory products or metabolism. Therapy has evolved via targeting of protein kinase B signaling or somatostatin receptors with drugs or isotopes (peptide-receptor radiotherapy). With DNA sequencing, rarely identified activating mutations confirm that tumor suppressor genes are relevant. Genomic approaches focusing on cancer-associated genes and signaling pathways likely will remain uninformative. Their uniquely dissimilar molecular profiles mean individual tumors are unlikely to be easily or uniformly targeted by therapeutics currently linked to standard cancer genetic paradigms. The prevalence of menin mutations in pancreatic NEN and P27^KIP1 mutations in small intestinal NEN represents initial steps to identifying a regulatory commonality in GEP-NEN. Transcriptional profiling and network-based analyses may define the cellular toolkit. Multianalyte diagnostic tools facilitate more accurate molecular pathologic delineations of NEN for assessing prognosis and identifying strategies for individualized patient treatment. GEP-NEN remain unique, poorly understood entities, and insight into their pathobiology and molecular mechanisms of growth and metastasis will help identify the diagnostic and therapeutic weaknesses of this neoplasia.