The Fanconi anemia pathway sensitizes to DNA alkylating agents by inducing JNK-p53-dependent mitochondrial apoptosis in breast cancer cells

Genetic modulation of longitudinal change in neurocognitive function among adult glioma patients

PURPOSE

Impaired neurocognitive function (NCF) is extremely common in patients with higher grade primary brain tumor. We previously reported evidence of genetic variants associated with NCF in glioma patients prior to treatment. However, little is known about the effect of genetic variants on NCF decline after adjuvant therapy.

METHODS

Patients (N = 102) completed longitudinal NCF assessments that included measures of verbal memory, processing speed, and executive function. Testing was conducted in the postoperative period with an average follow up interval of 1.3 years. We examined polymorphisms in 580 genes related to five pathways (inflammation, DNA repair, metabolism, cognitive, and telomerase).

RESULTS

Five polymorphisms were associated with longitudinal changes in processing speed and 14 polymorphisms with executive function. Change in processing speed was strongly associated with MCPH1 rs17631450 (P = 2.2 × 10^-7) and CCDC26 rs7005206 (P = 9.3 × 10^-7) in the telomerase pathway; while change in executive function was more strongly associated with FANCF rs1514084 (P = 2.9 × 10^-6) in the DNA repair pathway and DAOA rs12428572 (P = 2.4 × 10^-5) in the cognitive pathway. Joint effect analysis found significant genetic-dosage effects for longitudinal changes in processing speed (P_trend = 1.5 × 10^-10) and executive function (P_trend = 2.1 × 10^-11). In multivariable analyses, predictors of NCF decline included progressive disease, lower baseline NCF performance, and more at-risk genetic variants, after adjusting for age, sex, education, tumor location, histology, and disease progression.

CONCLUSION

Our longitudinal analyses revealed that polymorphisms in telomerase, DNA repair, and cognitive pathways are independent predictors of decline in NCF in glioma patients.

Development of a 3D functional assay and identification of biomarkers, predictive for response of high-grade serous ovarian cancer (HGSOC) patients to poly-ADP ribose polymerase inhibitors (PARPis): targeted therapy

Background

Poly(ADP-ribose) polymerase inhibitors (PARPis) specifically target homologous recombination deficiency (HRD) cells and display good therapeutic effect in women with advanced-stage BRCA1/2-mutated breast and epithelial ovarian cancer (EOC). However, about 50% of high grade serous ovarian cancers (HGSOC) present with HRD due to epigenetic BRCA1 inactivation, as well as genetic/epigenetic inactivation(s) of other HR genes, a feature known as “BRCAness”. Therefore, there is a potential for extending the use of PARPis to these patients if HR status can be identified.

Methods

We have developed a 3D (spheroid) functional assay to assess the sensitivity of two PARPis (niraparib and olaparib) in ascites-derived primary cell cultures (AsPCs) from HGSOC patients. A method for AsPCs preparation was established based on a matrix (agarose), allowing for easy isolation and successive propagation of monolayer and 3D AsPCs. Based on this method, we performed cytotoxicity assays on 42 AsPCs grown both as monolayers and spheroids.

Results

The response to PARPis treatment in monolayer AsPCs, was significantly higher, compared to 3D AsPCs, as 88% and 52% of the monolayer AsPCs displayed sensitivity to niraparib and olaparib respectively, while 66% of the 3D AsPCs were sensitive to niraparib and 38% to olaparib, the latter being more consistent with previous estimates of HRD (40%–60%) in EOC. Moreover, niraparib displayed a significantly stronger cytotoxic effect in both in 3D and monolayer AsPCs, which was confirmed by consecutive analyses of the HR pathway activity (γH2AX foci formation) in PARPis-sensitive and resistant AsPCs. Global gene expression comparison of 6 PARPi-resistant and 6 PARPi-sensitive 3D AsPCs was indicative for the predominant downregulation of numerous genes and networks with previously demonstrated roles in EOC chemoresistance, suggesting that the PARPis-sensitive AsPCs could display enhanced sensitivity to other chemotherapeutic drugs, commonly applied in cancer management. Microarray data validation identified 24 potential gene biomarkers associated with PARPis sensitivity. The differential expression of 7 selected biomarkers was consecutively confirmed by immunohistochemistry in matched EOC tumor samples.

Conclusion

The application of this assay and the potential biomarkers with possible predictive significance to PARPis therapy of EOC patients now need testing in the setting of a clinical trial.

Nitidine chloride induces S phase cell cycle arrest and mitochondria-dependent apoptosis in HaCaT cells and ameliorates skin lesions in psoriasis-like mouse models

Psoriasis is a common dermatosis causing considerable inconvenience to 4% of the general population. Traditional psoriasis treatments often cause side effects, drug resistance and complications, necessitating development of safer and more effective treatments. In this study, we screened over 600 natural compounds to identify viability inhibitors of human HaCaT keratinocytes cultured in vitro. The results showed that nitidine chloride was a highly effective inhibitor. Further studies revealed that nitidine chloride inhibited HaCaT proliferation and induced S phase cell cycle arrest; these effects were associated with reduced DNA synthesis, decreased Ki67, cyclin A, and cyclin D1 levels, and increased p53 protein expression. Nitidine chloride also significantly downregulated bcl-2 and upregulated bax, cleaved caspase-9 and cleaved caspase-3. Mechanistic studies revealed that nitidine chloride-induced apoptosis involved the c-Jun N-terminal kinase (JNK) pathway. More importantly, in 12-O-tetradecanoyl-phorbol-13-acetate (TPA)- and imiquimod (IMQ)-induced epidermal hyperplasia and inflammation models, nitidine chloride inhibited topical edema in mouse ear and back skin, substantially reducing tissue thickness and weight. In some cases, nitidine chloride also ameliorated conditions caused by TPA and IMQ, such as angiogenesis and infiltration of large numbers of inflammatory cells around blood vessels. Additionally, nitidine chloride inhibited the expression of various proinflammatory cytokines in the two animal models. In conclusion, our results are the first to demonstrate that nitidine chloride inhibits the proliferation of HaCaT cells, induces apoptosis partly via the JNK signaling pathway in vitro and ameliorates skin lesions and inflammation in vivo, making it an appropriate candidate for psoriasis treatment.

Alteronol Enhances the Anti-tumor Activity and Reduces the Toxicity of High-Dose Adriamycin in Breast Cancer

The first-line chemotherapy drug adriamycin (ADM) is widely used for the treatment of breast cancer, but the acquired drug resistance and the normal tissue toxicity remain clinical challenges. Alteronol has been reported to exert wide-ranging anti-tumor activity. In this study, we firstly examined the synergistic anti-tumor effects and the underlying mechanisms of alteronol combined with ADM in breast cancer. We have found that the combination of alteronol and ADM significantly suppressed the expression levels of the cell cycle-related proteins (CDC2 and Cyclin B1) and induced cell cycle arrest at the G2/M phase, leading to cell proliferation inhibition in breast cancer 4T1 cells. Moreover, co-treatment of alteronol and ADM (i) remarkably activated p38 and JNK kinases, (ii) elevated ROS levels, (iii) triggered mitochondrial dysfunction, (iv) released cytochrome c into the cytoplasm, (v) upregulated apoptosis-related proteins, e.g., cleaved PARP, Bax, and cleaved caspase-3/9, and (vi) downregulated the expression of Bcl-2, followed by apoptosis. Furthermore, our in vivo studies showed that the low-dose combination of alteronol (2 mg/kg) and ADM (1 mg/kg) significantly inhibited tumor growth in tumor bearing mice, and the anti-tumor effect of the combination was the same as that of high-dose ADM (8 mg/kg). In addition, the low-dose combination group showed lower toxicities to major organs than the high-dose ADM group. Taken together, these data demonstrate that the low-dose combination of alteronol and ADM could notably improve the anti-tumor activity and have lower toxicities to major organs than those in high-dose ADM group.