NM23-H1 BLOCKS CELL MOTILITY INDEPENDENTLY OF ITS KNOWN ENZYMATIC ACTIVITIES IN A COHORT OF HUMAN MELANOMA CELLS

The metastasis suppressor gene NM23-H1 has been shown to possess three enzymatic activities including nucleoside diphosphate kinase, histidine-dependent protein kinase and 3’-5’ exonuclease activity. While these properties have been demonstrated in vitro using recombinant proteins, the contribution of these activities to suppression of metastatic dissemination is unknown. Site-directed mutagenesis studies were used to identify amino acid residues which are required for proper function of each enzymatic activity associated with H1, providing a platform for studying the importance of each function on an individual basis. To assess the relevance of these activities to melanoma progression, a panel of mutants harboring selective lesions disrupting the enzymatic activities of H1 were overexpressed using stable transfection in two melanoma cell lines, WM793 (isolated from a vertical growth phase human melanoma), and the metastatic derivative cell line 1205LU. In vitro correlates of metastasis measuring motility and invasion were used in an attempt to identify the mechanism mediating H1-dependent motility suppression of cancer cells. Surprisingly, all mutants studied retained full motility suppression in this setting, suggesting that the enzymatic functions associated with H1 are not required for inhibiting cell migration. Instead, gene expression analyses conducted on the panel of stable transfectants indicate that differences in steady-state mRNA levels of genes involved in mitogen-activated protein kinase (MAPK) signaling showed significant correlations with H1 expression and motility suppression. RNAi studies have confirmed that H1-dependent modulation of the expression of two genes in particular, BRAP and IQGAP2, contribute to the observed phenotype, suggesting a novel mechanism used by NM23 to control cellular migration in human melanoma

Preclinical Evaluation of Artesunate as an Antineoplastic Agent in Ovarian Cancer Treatment

BACKGROUND: Ovarian cancer is the deadliest gynecologic malignancy despite current first-line treatment with a platinum and taxane doublet. Artesunate has broad antineoplastic properties but has not been investigated in combination with carboplatin and paclitaxel for ovarian cancer treatment. METHODS: Standard cell culture technique with commercially available ovarian cancer cell lines were utilized in cell viability, DNA damage, and cell cycle progression assays to qualify and quantify artesunate treatment effects. Additionally, the sequence of administering artesunate in combination with paclitaxel and carboplatin was determined. The activity of artesunate was also assessed in 3D organoid models of primary ovarian cancer and RNAseq analysis was utilized to identify genes and the associated genetic pathways that were differentially regulated in artesunate resistant organoid models compared to organoids that were sensitive to artesunate. RESULTS: Artesunate treatment reduces cell viability in 2D and 3D ovarian cancer cell models. Clinically relevant concentrations of artesunate induce G1 arrest, but do not induce DNA damage. Pathways related to cell cycle progression, specifically G1/S transition, are upregulated in ovarian organoid models that are innately more resistant to artesunate compared to more sensitive models. Depending on the sequence of administration, the addition of artesunate to carboplatin and paclitaxel improves their effectiveness. CONCLUSIONS: Artesunate has preclinical activity in ovarian cancer that merits further investigation to treat ovarian cancer

Association of an Inherited Genetic Variant With Vincristine-Related Peripheral Neuropathy in Children With Acute Lymphoblastic Leukemia

ImportanceWith cure rates of childhood acute lymphoblastic leukemia (ALL) exceeding 85%, there is a need to mitigate treatment toxicities that can compromise quality of life, including peripheral neuropathy from vincristine treatment.ObjectiveTo identify genetic germline variants associated with the occurrence or severity of vincristine-induced peripheral neuropathy in children with ALL.Design, setting, and participantsGenome-wide association study of patients in 1 of 2 prospective clinical trials for childhood ALL that included treatment with 36 to 39 doses of vincristine. Genome-wide single-nucleotide polymorphism (SNP) analysis and vincristine-induced peripheral neuropathy were assessed in 321 patients from whom DNA was available: 222 patients (median age, 6.0 years; range, 0.1-18.8 years) enrolled in 1994-1998 in the St Jude Children's Research Hospital protocol Total XIIIB with toxic effects follow-up through January 2001, and 99 patients (median age, 11.4 years; range, 3.0-23.8 years) enrolled in 2007-2010 in the Children's Oncology Group (COG) protocol AALL0433 with toxic effects follow-up through May 2011. Human leukemia cells and induced pluripotent stem cell neurons were used to assess the effects of lower CEP72 expression on vincristine sensitivity.ExposureTreatment with vincristine at a dose of 1.5 or 2.0 mg/m2.Main outcomes and measuresVincristine-induced peripheral neuropathy was assessed at clinic visits using National Cancer Institute criteria and prospectively graded as mild (grade 1), moderate (grade 2), serious/disabling (grade 3), or life threatening (grade 4).ResultsGrade 2 to 4 vincristine-induced neuropathy during continuation therapy occurred in 28.8% of patients (64/222) in the St Jude cohort and in 22.2% (22/99) in the COG cohort. A SNP in the promoter region of the CEP72 gene, which encodes a centrosomal protein involved in microtubule formation, had a significant association with vincristine neuropathy (meta-analysis P = 6.3×10(-9)). This SNP had a minor allele frequency of 37% (235/642), with 50 of 321 patients (16%; 95% CI, 11.6%-19.5%) homozygous for the risk allele (TT at rs924607). Among patients with the high-risk CEP72 genotype (TT at rs924607), 28 of 50 (56%; 95% CI, 41.2%-70.0%) developed at least 1 episode of grade 2 to 4 neuropathy, a higher rate than in patients with the CEP72 CC or CT genotypes (58/271 patients [21.4%; 95% CI, 16.9%-26.7%]; P = 2.4×10(-6)). The severity of neuropathy was greater in patients homozygous for the TT genotype compared with patients with the CC or CT genotype (2.4-fold by Poisson regression [P<.0001] and 2.7-fold based on mean grade of neuropathy: 1.23 [95% CI, 0.74-1.72] vs 0.45 [95% CI, 0.3-0.6]; P = .004 by t test). Reducing CEP72 expression in human neurons and leukemia cells increased their sensitivity to vincristine.Conclusions and relevanceIn this preliminary study of children with ALL, an inherited polymorphism in the promoter region of CEP72 was associated with increased risk and severity of vincristine-related peripheral neuropathy. If replicated in additional populations, this finding may provide a basis for safer dosing of this widely prescribed anticancer agent

Association of an Inherited Genetic Variant With Vincristine-Related Peripheral Neuropathy in Children With Acute Lymphoblastic Leukemia

IMPORTANCE: With cure rates of childhood acute lymphoblastic leukemia (ALL) exceeding 85%, there is compelling need to mitigate treatment toxicities that can compromise quality of life. Peripheral neuropathy is the major dose-limiting toxicity of the microtubule inhibitor vincristine, an anticancer agent given to every child with ALL. OBJECTIVE: Identify genetic germline variants associated with the occurrence or severity of vincristine-induced peripheral neuropathy in children with ALL. DESIGN, SETTING AND PARTICIPANTS: All patients had been enrolled in one of two prospective clinical trials for childhood ALL that included treatment with 36–39 doses of vincristine. Genome-wide single nucleotide polymorphism (SNP) analysis and vincristine-induced peripheral neuropathy were assessed in all patients from whom DNA was available (n=321 patients); 222 patients (median age at 6.0 years, range 0.1–18.8 years) enrolled between 1994–1998 on the St. Jude Children’s Research Hospital protocol Total XIIIB (St. Jude cohort) with toxicity followed through January 2001, and 99 patients (median age 11.4 years, range 3.0–23.8 years) enrolled between 2007–2010 on the Children’s Oncology Group protocol AALL0433 (COG cohort) with toxicity followed through May 2011. Human leukemia cells and induced pluripotent stem cell neurons were used to assess the effects of lower CEP72 expression on vincristine sensitivity. EXPOSURES: Treatment with vincristine at a dosage of 1.5 or 2.0 mg/m(2) as a component of protocol directed chemotherapy for childhood ALL. MAIN OUTCOMES AND MEASURES: Vincristine-induced peripheral neuropathy was assessed at each clinic visit using the National Cancer Institute Common Terminology Criteria for Adverse Events and prospectively graded as mild (grade 1), moderate (grade 2), serious/disabling (grade 3), or life-threatening (grade 4). RESULTS: Grade 2–4 vincristine-induced neuropathy during continuation therapy occurred in 28.8% of patients (n=64 of 222) in the St. Jude cohort and in 22.2% of patients (n=22 of 99) in the COG cohort. A SNP in the promoter region of the CEP72 gene, which encodes a centrosomal protein involved in microtubule formation, had a significant association with vincristine neuropathy (meta p =6.3 × 10(−9)). This SNP had a minor allele frequency of 37% (235/642), with 50 of 321 patients (16%, 95% CI 11.6%–19.5%) homozygous for the risk allele (TT at rs924607). Among patients with the high-risk CEP72 genotype (TT at rs924607), 28 of 50 patients (56%, 95% CI 41.2–70.0) developed at least one episode of grade 2–4 neuropathy, a higher rate than in patients with the CEP72 CC or CT genotype (58 of 271 patients; 21.4%, 95% CI 16.9–26.7); p=2.4×10(−6). The severity (grade) of neuropathy was greater (2.4-fold by Poisson regression (p<0.0001), 2.7-fold based on mean grade of neuropathy (1.23 [95% CI 0.74 – 1.72] versus 0.45 [95% CI 0.3 – 0.6]; t test p=0.004)) in patients homozygous for the CEP72 risk allele (TT genotype), compared to patients with the CC or CT genotype. The CEP72 promoter SNP was shown to create a binding site for a transcriptional repressor causing lower mRNA expression, and reducing CEP72 expression in human neurons and leukemia cells increased their sensitivity to vincristine. CONCLUSIONS: In this preliminary study of children with ALL, an inherited polymorphism in the promoter region of CEP72 was associated with increased risk and severity of vincristine-related peripheral neuropathy. If replicated in additional populations, this finding may provide a basis for safer dosing of this widely prescribed anticancer agent