Li Yang

Research Progress of PARP Inhibitor Monotherapy and Combination Therapy for Endometrial Cancer

: Endometrial cancer is one of the three most common malignant tumors in the female reproductive system. Advanced and recurrent endometrial cancers have poor prognoses and lack effective treatments. Poly (ADP-ribose) polymerase (PARP) inhibitors have been applied to many different types of tumors, and they can selectively kill tumor cells that are defective in homologous recombination repair. Endometrial cancer is characterized by mutations in homologous recombination repair genes; accordingly, PARP inhibitors have achieved positive results in off-label treatments of endometrial cancer cases. Clinical trials of PARP inhibitors as monotherapies and within combination therapies for endometrial cancer are ongoing. For this review, we searched PubMed with “endometrial cancer” and “PARP inhibitor” as keywords, and we used “olaparib”, “rucaparib”, “niraparib” and “talazoparib” as search terms in clinicaltrials.gov for ongoing trials. The literature search ended in October 2020, and only English-language publications were selected. Multiple studies confirm that PARP inhibitors play an important role in killing tumor cells with defects in homologous recombination repair. Its combination with immune checkpoint inhibitors, PI3K/AKT/mTOR pathway inhibitors, cell cycle checkpoint inhibitors, and other drugs can improve the treatment of endometrial cancer.

Applications and Prospects of Single‐Cell RNA Sequencing and Spatial Transcriptomics in Cervical Cancer

Cervical cancer (CC) is the fourth commonest malignant tumor among women worldwide and is characterized by high heterogeneity and a complex ecosystem. A comprehensive understanding of the heterogeneity of tumors and the tumor microenvironment (TME) is crucial for effective CC management. Single‐cell RNA sequencing (scRNA‐seq) is a powerful tool that can be employed to unveil the heterogeneity of tumors and the TME, as well as to elucidate the evolutionary trajectories of tumors. Spatial transcriptomics (ST) technology, on the other hand, can address the complexity and diversity of the spatial microenvironment of tumors, thereby compensating for the limitations of scRNA‐seq. As emerging technologies, both scRNA‐seq and ST are increasingly being utilized in CC research. In this review, we summarized the latest advancements in scRNA‐seq and ST for CC, with a focus on investigating tumor heterogeneity, the TME, tumor evolutionary trajectories, treatment resistance mechanisms, and potential therapeutic targets. These insights collectively contribute to the development of more effective treatment and prevention strategies for CC.

Pan-cancer analysis of ARNT2 and its oncogenic role in cervical cancer

This study aims to elucidate the role of aryl hydrocarbon receptor nuclear transporter 2 (ARNT2) in cervical cancer (CC) and explore the potential mechanism by which ARNT2 promotes the progression of CC through the protein phosphatase 2A (PP2A)/Akt signaling pathway. Bioinformatics tools were used to analyze the expression level of ARNT2 in cancer and its correlation with cancer prognosis. Western Blot and immunohistochemistry staining were used to detect the expression of ARNT2 protein in CC tissues and cells. ARNT2 was knocked down in SiHa and HeLa cells, respectively. Cell Counting Kit-8 assay and colony formation assay were used to detect changes in cell proliferation. Transwell assay and plate scratch assay were used to detect changes in cell migration and invasion. Western Blot assay was used to detect changes in the expression of PP2A/Akt signaling pathway after ARNT2 expression was downregulated. Finally, a CC xenograft tumor model was constructed to evaluate the effect of ARNT2 on SiHa cell tumorigenesis in vivo. ARNT2 is highly expressed in tumor tissues and cell lines. ARNT2 knockdown can significantly inhibit the proliferation, invasion and migration of SiHa and HeLa cells in vitro and in xenograft models. Further studies have shown that ARNT2 may promote tumor formation by regulating the PP2A/Akt pathway. ARNT2 promotes the malignant biological behavior of CC cells through the PP2A/Akt signaling pathway, confirming its potential as a prognostic marker for CC.

LncRNA MAFG-AS1 promotes the malignant phenotype of ovarian cancer by upregulating NFKB1-dependent IGF1

Long non-coding RNAs (lncRNAs) were recently recognized to vitally function in a variety of cancer cellular events, including epithelial-mesenchymal transition (EMT), invasion, and migration, particularly in ovarian cancer (OC). Herein, we sought to investigate the potential role of MAFG-AS1 in the malignant behaviors of OC cells. The binding affinity between MAFG-AS1, miR-339-5p, NFKB1 or IGF1 was characterized so as to identify the underlying mechanism of corresponding their interactions. We conducted MAFG-AS1 overexpression or knockdown along with NFKB1 and IGF1 silencing to examine their effects on the EMT, migration, and invasion of OC cells. Tumors were xenografted in nude mice to validate the in vitro findings. Our data showed significantly high expression pattern of MAFG-AS1 in the OC tissues and cells. Further mechanistic investigations revealed that MAFG-AS1 upregulated the IGF1 expression pattern through recruitment of NFKB1, whereas MAFG-AS1 upregulated the NFKB1 expression pattern through binding to miR-339-5p. Thus, MAFG-AS1 overexpression accelerated the EMT, invasion, and migration of OC cells, which could be annulled by silencing of IGF1 or NFKB1. Besides, our in vitro findings were successfully recapitulated in the xenograft mice. These results determined that MAFG-AS1 stimulated the OC malignant progression by upregulating the NFKB1-mediated IGF1 via miR-339-5p, thus highlighting a novel potential therapeutic target against OC.

circANKRD17(has_circ_0007883) confers paclitaxel resistance of ovarian cancer via interacting with FUS to stabilize FOXR2

Emerging numbers of endogenous circular RNAs (circRNAs) have gained much attention to serve as essential regulators in the carcinogenesis of human cancers. Unfortunately, the occurrence of paclitaxel (PTX) resistance to ovarian cancer remains to be responsible for the poor prognosis. Herein, the aim of our study is to reveal a dysregulation of a particular circRNA, circANKRD17 (has_circ_0007883), and its exact role involving in chemoresistance of ovarian cancer. Expression patterns of circANKRD17 in PTX-resistant ovarian cancer tissues and cell lines was examined using quantitative real-time PCR analysis. Role of circANKRD17 on drug resistance and cell viability was evaluated by CCK-8 assay. Colony formation was subjected to measure cell proliferation. Flow cytometry was employed to evaluate cell cycle either or cell apoptosis. Xenograft models were constructed for further in vivo confirmation. The cicrANKRD17/FUS/FOXR2 axis was demonstrated using bioinformatics analysis, RNA pull-down, as well as RNA immunoprecipitation assays. Dramatically high expressed circANKRD17 observed in ovarian cancer tissues and cells was correlated with PTX resistance, which indicated the poor prognosis. Functionally, knockdown of circANKRD17 decreased PTX resistance via inhibiting cell viability and inducing cell apoptosis. Mechanistically, circANKRD17 interacted with the RNA-binding protein, fused in sarcoma (FUS) to stabilize FOXR2. In summary, our study uncovered a novel machinery of circANKRD17/FUS/FOXR2 referring to ovarian cancer drug sensitivity and tumorigenesis, highlighting a potential strategy for circRNAs in chemoresistance.