Expression of mitotic-arrest deficiency 2 predicts the efficacy of neoadjuvant chemotherapy for locally advanced uterine cervical cancer

Single-cell sequencing reveals MYC targeting gene MAD2L1 is associated with prostate cancer bone metastasis tumor dormancy

Background

Among malignant tumors, bone metastasis is frequently associated with prostate cancer which is seen in about 80% of patients. During cancer treatments, some tumor cells switch to a "dormant mode" to help tumor cells avoid attack from the immune system and anti-tumor therapies. In this dormant mode, tumor cells can be resuscitated, causing cancer to reoccur. The generally accepted explanation for this phenomenon is that the tumor cells have spread to the bone marrow before treatment and are dormant in the bone marrow. However, the key mechanism for inducing and maintaining the dormancy of these prostate cancer disseminated tumor cells in the bone marrow is still unclear. Therefore, studying the dormancy mechanism of tumor cells in bone metastasis is of great significance for the treatment and the prevention of recurrence of prostate cancer.

Methods

We obtained single-cell RNA-seq data of tumors from mouse models of prostate cancer bone metastasis mouse model numbered (GSE147150) from the GEO database, and obtained RNA-seq expression data and clinical information from The Cancer Genome Atlas Program (TCGA) of prostate cancer patients from the USCS Xena database. Screening of differential genes and annotation of GO functions were performed separately. Subsequently, the screened differential genes were compared and analyzed with 50 classic Hallmark signaling pathways, and the prognosis analysis of prostate cancer patients in TCGA data was performed to discover the key genes of the dormant mechanism of tumor cells in bone metastasis, and obtain new biomarkers that can be used to predict the prognosis of patients.

Results

A total of 378 differentially expressed genes were screened, of which 293 were significantly up-regulated and 85 were significantly down-regulated. Among them, the up-regulated genes were mainly related to the immune response, and the down-regulated genes were mainly related to the cell cycle. Through GSVA (Gene set variation analysis), it is found that there are differences in a total of 3 signal pathways: COMPLEMENT, MYC_TARGETS_V1 and MYC_TARGETS_V2. By comparing and analyzing the significantly down-regulated genes in dormant tumor cells with MYC_TARGETS_V1, MYC_TARGETS_V2, three significantly down-regulated genes were obtained: Ccna2, Mad2L1 and Plk1.

Conclusion

In summary, our findings indicate that the MYC targeting gene Mad2L1 is potentially related to the dormancy mechanism of prostate cancer. At the same time, Mad2L1, a gene associated with dormant prostate cancer cells, may be used as a biomarker for prognostic survival.

Expression of epidermal growth factor-like domain 7 may be a predictive marker of the effect of neoadjuvant chemotherapy for locally advanced uterine cervical cancer

Neoadjuvant chemotherapy (NAC) followed by hysterectomy may be effective for the treatment of locally advanced uterine cervical cancer and improve patient prognosis. It is important to identify markers that are able to predict whether NAC may be successful. Epidermal growth factor-like domain 7 (EGFL7) regulates vascular sprouting in blood vessel formation. In numerous types of human cancer, EGFL7 is upregulated and inhibits endothelial cell adhesion molecules, decreasing vascular tightness and, thus, increasing vascular permeability. It is considered that the overexpression of EGFL7 is able to inhibit drug delivery, resistance to apoptosis and the epithelial-to-mesenchymal transition. In the current study, 63 patients with locally advanced uterine cervical cancer were reviewed and classified as stage IIIA-IIIB using the International Federation of Gynecology and Obstetrics criteria. These patients (aged <70 years) were treated at Osaka City University Medical School Hospital, Japan, between 1995 and 2010. Tumor tissue samples were obtained by biopsy prior to NAC. The tissue samples were classified as group 1 or 2 depending on the efficacy of NAC. Surgery and radiotherapy were administered in group 1 (n=36), for which NAC was effective. In the patients of group 2 NAC was not effective, and radiotherapy alone was administered (n=27). The expression of EGFL7 and Snail was examined in paraffin-embedded tissue sample sections using the avidin-biotin peroxidase complex method. The results indicated that EGFL7 expression levels were significantly higher in group 2, as compared with group 1 (P<0.001). A similar result was observed for the expression levels of Snail (P=0.001). Group 1 exhibited significantly longer overall survival times compared with group 2 (P=0.001). The patients were also classified into a low EGFL7 expression level group (weighted score of ≤6) and a high EGFL7 expression level group (weighted score of ≥8). NAC was observed to be significantly more effective in the low EGFL7 expression level group (P<0.001), as compared with the high expression level group. The results suggest that the expression levels of EGFL7 may be a potential predictive marker of the efficacy of NAC for the treatment of locally advanced uterine cervical cancer.

MAD2γ, a novel MAD2 isoform, reduces mitotic arrest and is associated with resistance in testicular germ cell tumors

Background: Prolonged mitotic arrest in response to anti-cancer chemotherapeutics, such as DNA-damaging agents, induces apoptosis, mitotic catastrophe, and senescence. Disruptions in mitotic checkpoints contribute resistance to DNA-damaging agents in cancer. MAD2 has been associated with checkpoint failure and chemotherapy response. In this study, a novel splice variant of MAD2, designated MAD2γ, was identified, and its association with the DNA damage response was investigated.

Methods: Endogenous expression of MAD2γ and full-length MAD2 (MAD2α) was measured using RT-PCR in cancer cell lines, normal foreskin fibroblasts, and tumor samples collected from patients with testicular germ cell tumors (TGCTs). A plasmid expressing MAD2γ was transfected into HCT116 cells, and its intracellular localization and checkpoint function were evaluated according to immunofluorescence and mitotic index.

Results: MAD2γ was expressed in several cancer cell lines and non-cancerous fibroblasts. Ectopically expressed MAD2γ localized to the nucleus and reduced the mitotic index, suggesting checkpoint impairment. In patients with TGCTs, the overexpression of endogenous MAD2γ, but not MAD2α, was associated with resistance to cisplatin-based chemotherapy. Likewise, cisplatin induced the overexpression of endogenous MAD2γ, but not MAD2α, in HCT116 cells.

Conclusions: Overexpression of MAD2γ may play a role in checkpoint disruption and is associated with resistance to cisplatin-based chemotherapy in TGCTs.

Structure-biological function relationship extended to mitotic arrest-deficient 2-like protein Mad2 native and mutants-new opportunity for genetic disorder control

Overexpression of mitotic arrest-deficient proteins Mad1 and Mad2, two components of spindle assembly checkpoint, is a risk factor for chromosomal instability (CIN) and a trigger of many genetic disorders. Mad2 transition from inactive open (O-Mad2) to active closed (C-Mad2) conformations or Mad2 binding to specific partners (cell-division cycle protein 20 (Cdc20) or Mad1) were targets of previous pharmacogenomics studies. Here, Mad2 binding to Cdc20 and the interconversion rate from open to closed Mad2 were predicted and the molecular features with a critical contribution to these processes were determined by extending the quantitative structure-activity relationship (QSAR) method to large-size proteins such as Mad2. QSAR models were built based on available published data on 23 Mad2 mutants inducing CIN-related functional changes. The most relevant descriptors identified for predicting Mad2 native and mutants action mechanism and their involvement in genetic disorders are the steric (van der Waals area and solvent accessible area and their subdivided) and energetic van der Waals energy descriptors. The reliability of our QSAR models is indicated by significant values of statistical coefficients: Cross-validated correlation q² (0.53–0.65) and fitted correlation r² (0.82–0.90). Moreover, based on established QSAR equations, we rationally design and analyze nine de novo Mad2 mutants as possible promoters of CIN.

Sirtuin1 expression predicts the efficacy of neoadjuvant chemotherapy for locally advanced uterine cervical cancer

Cisplatin-based, cyclic balloon-occluded arterial infusion, neoadjuvant chemotherapy (NAC) has previously been reported to enable hysterectomy in patients with locally advanced cervical cancer. Sirtuin1 (SIRT1) is a nicotinamide adenine dinucleotide (NAD⁺)-dependent histone deacetylase that deacetylates a number of proteins and is overexpressed in several human malignancies. Upregulation of SIRT1 has been reported to induce tumorigenesis and chemoresistance. To assess the role of SIRT1 in uterine cervical cancer, the outcomes in 62 patients aged <70 years with locally advanced International Federation of Gynecology and Obstetrics (FIGO) stage IIIA-IIIB uterine cervical cancer were reviewed between 1995 and 2010. Tumor samples were obtained by biopsy prior to NAC. The patients were separated into two groups. One group comprised of the patients in which NAC was effective, surgery and radiotherapy were performed (NAC+OP+R group; n=35), and the second group contained patients in which NAC was ineffective and radiation therapy was performed (NAC+R group; n=27). SIRT1 and p53 expression was assessed immunohistochemically in paraffin-embedded sections. SIRT1 expression was significantly higher in the NAC+R compared to the NAC+OP+R group (P<0.001), as was p53 expression (P=0.001). The overall survival time was significantly longer in the NAC+OP+R compared to the NAC+R group (P=0.001). Following the division of patients into two groups based on SIRT1 level, low (weighted score ≤4, n=30), and high level (weighted score ≥6, n=32) groups, the former group was significantly more sensitive to NAC (P<0.001). Collectively, these results indicate that SIRT1 expression may predict the efficacy of NAC as a treatment for locally advanced uterine cervical cancer.

MAD2 Expression in Ovarian Carcinoma: Different Expression Patterns and Levels among Various Types of Ovarian Carcinoma and Its Prognostic Significance in High-Grade Serous Carcinoma

BACKGROUND

Mitotic arrest deficiency protein 2 (MAD2) is a key component of spindle assembly checkpoint function, which mediates cell apoptosis through microtubule kinetics. Aberrant expression of MAD2 is believed to be associated with the development of chromosome instability. MAD2 also has a signihicant role in cellular drug resistance to taxane chemotherapeutic agents.

METHODS

Expression of MAD2 and p53 was investigated using immunohistochemistry in 85 cases of ovarian carcinomas. Clinicopathological data including progression-free survival were analyzed.

RESULTS

A significant (p=.035) association was observed between the grade of serous carcinoma and the expression level of MAD2. While low-grade serous carcinoma showed a low-level expression of MAD2, high-grade serous carcinoma showed a high-level expression of MAD2. We also determined that low-level expression of MAD2 was associated with reduced progression-free survival (PFS) (p=.016) in high-grade serous carcinoma.

CONCLUSIONS

MAD2 expression in ovarian carcinoma is related to the grade of serous carcinoma and PFS of high-grade serous carcinoma. Expression level of MAD2 detected by immunohistochemistry may serve as an indicator in predicting the response of microtubule-interfering chemotherapeutic agents.