Molecular markers of DNA damage and repair in cervical cancer patients treated with cisplatin neoadjuvant chemotherapy: an exploratory study

NUPR1 contributes to activate TFE3-dependent autophagy leading to cervical cancer proliferation

Cervical cancer is a malignant tumor that occurs in the cervix of women and endangers their lives. In this study, we aimed to assess the roles of NUPR1 and TFE3 in cervical cancer. The Cancer Genome Atlas (TCGA) database was used to assess the correlation between NUPR1 and TFE3 expression in cervical cancer. By silencing NUPR1 and TFE3, and through 3-MA treatment, we determined whether their silencing could lead to lysosomal dysfunction, thereby inhibiting autophagy and cervical cancer cell proliferation. Their roles were further analyzed using molecular biological methods. Silencing NUPR1 and TFE3 inhibited cell proliferation and decreased the expression levels of autophagy-related genes, p62 and LC3B. By tracing lysosomes within cells, NUPR1 and TFE3 knockdown were found to induce lysosomal dysfunction, thereby inhibiting autophagy. In vivo experimental studies have shown that knockdown of NUPR1 and TFE3 can inhibit tumor growth, while reducing the ki67, p62, and LC3B expression levels and promoting apoptosis. Furthermore, the expression levels of lamp1 and lamp2, and the phosphorylation of PI3K (p-PI3K) and Akt (p-Akt) were significantly reduced after NUPR1 and TFE3 knockdown. However, treatment with 3-MA and overexpression of TFE3 could partially reverse the effect of silencing NUPR1. Overall, silencing NUPR1 reduced autophagy by inhibiting TFE3 in cervical cancer. Our results supply new evidence for the use of NUPR1 as a therapeutic target in cervical cancer.

Genotoxicity and apoptotic effect of silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine on malignant melanoma cells, SK-MEL-28

Complexes of coinage metals can potentially be used as alternatives to platinum-based chemotherapeutic drugs. Silver is a coinage metal that can potentially improve the spectrum of efficacy in various cancers treatment, such as malignant melanoma. Melanoma is the most aggressive form of skin cancer that is often diagnosed in young and middle-aged adults. Silver has high reactivity with skin proteins and can be developed as a malignant melanoma treatment modality. Therefore, this study aims to identify the anti-proliferative and genotoxic effects of silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine ligands in the human melanoma SK-MEL-28 cell line. The anti-proliferative effects of a series of silver(I) complex compounds labelled as OHBT, DOHBT, BrOHBT, OHMBT, and BrOHMBT were evaluated on SK-MEL-28 cells by using the Sulforhodamine B assay. Then, DNA damage analysis was performed in a time-dependent manner (30 min, 1 h and 4 h) by using alkaline comet assay to investigate the genotoxicity of OHBT and BrOHMBT at their respective IC₅₀ values. The mode of cell death was studied using Annexin V-FITC/PI flow cytometry assay. Our current findings demonstrated that all silver(I) complex compounds showed good anti-proliferative activity. The IC₅₀ values of OHBT, DOHBT, BrOHBT, OHMBT, and BrOHMBT were 2.38 ± 0.3 μM, 2.70 ± 0.17 μM, 1.34 ± 0.22 μM, 2.82 ± 0.45 μM, and 0.64 ± 0.04 μM respectively. Then, DNA damage analysis showed that OHBT and BrOHMBT could induce DNA strand breaks in a time-dependent manner, with OHBT being more prominent than BrOHMBT. This effect was accompanied by apoptosis induction in SK-MEL-28, as evaluated using Annexin V-FITC/PI assay. In conclusion, silver(I) complexes with mixed-ligands of thiosemicarbazones and diphenyl(p-tolyl)phosphine exerted anti-proliferative activities by inhibiting cancer cell growth, inducing significant DNA damage and ultimately resulting in apoptosis.

Dose-Intense Cisplatin-Based Neoadjuvant Chemotherapy Increases Survival in Advanced Cervical Cancer: An Up-to-Date Meta-Analysis

PURPOSE

We set out to demonstrate the benefit of using dose-intense cisplatin-based neoadjuvant chemotherapy in terms of overall survival and progression-free survival.

METHODS

We searched through MEDLINE and Cochrane Library databases up to May 2021 to identify randomized clinical trials comparing the benefit of using cisplatin-based neoadjuvant chemotherapy followed by local treatment with local treatment alone for the treatment of locally advanced cervical cancer. The PRISMA statement was applied.

RESULTS

Twenty-two randomized clinical trials were retrieved between 1991 and 2019, corresponding to 3632 women with FIGO stages IB2-IVA cervical cancer. More than 50% of the randomized clinical trials were assessed as having a low risk of bias. There was no benefit of neoadjuvant chemotherapy on overall survival, but there was significant heterogeneity across studies (I2 = 45%, p = 0.01). In contrast, dose-intense cisplatin at over 72.5 mg/m2/3 weeks was significantly associated with increased overall survival (RR = 0.87, p < 0.05) with no heterogeneity across the pooled studies (I2 = 36%, p = 0.11). The survival benefit was even greater when cisplatin was administered at a dose over 105 mg/m2/3 weeks (RR = 0.79, p < 0.05).

CONCLUSION

Even though radiotherapy combined with weekly cisplatin-based chemotherapy remains standard of care for the treatment of locally advanced cervical cancer, our meta-analysis makes it possible to consider the use of dose-intense cisplatin-based neoadjuvant chemotherapy when local treatment is suboptimal and opens perspectives for designing new clinical trials in this setting. Neoadjuvant chemotherapy could be proposed when surgery is local treatment instead of standard chemoradiotherapy for the treatment of locally advanced cervical cancer.

MAP4K4 mediates the SOX6-induced autophagy and reduces the chemosensitivity of cervical cancer

There are nearly 40% of cervical cancer patients showing poor response to neoadjuvant chemotherapy that can be induced by autophagy, however, the underlying mechanism has not yet been fully clarified. We previously found that Sex-determining region of Y-related high-mobility-group box 6 (SOX6), a tumor suppressor gene or oncogene in several cancers, could induce autophagy in cervical cancer. Accordingly, this study aims to investigate the mechanism of SOX6-induced autophagy and its potential significance in the platinum-based chemotherapy of cervical cancer. Firstly, we found that SOX6 could promote autophagy in cervical cancer cells depending on its HMG domain. Mitogen-activated protein kinase kinase kinase kinase-4 (MAP4K4) gene was identified as the direct target gene of SOX6, which was transcriptionally upregulated by binding the HMG domain of SOX6 protein to its double-binding sites within MAP4K4 gene promoter. MAP4K4 mediated the SOX6-induced autophagy through inhibiting PI3K-Akt-mTOR pathway and activating MAPK/ERK pathway. Further, the sensitivity of cervical cancer cells to cisplatin chemotherapy could be reduced by the SOX6-induced autophagy in vitro and in vivo, while such a phenomenon could be turned over by autophagy-specific inhibitor and MAP4K4 inhibitor, respectively. Moreover, cisplatin itself could promote the expression of endogenous SOX6 and subsequently the MAP4K4-mediated autophagy in cervical cancer cells, which might in turn reduce the sensitivity of these cells to cisplatin treatment. These findings uncovered the underlying mechanism and potential significance of SOX6-induced autophagy, and shed new light on the usage of MAP4K4 inhibitor or autophagy-specific inhibitor for sensitizing cervical cancer cells to the platinum-based chemotherapy.

USP37 regulates DNA damage response through stabilizing and deubiquitinating BLM

The human RecQ helicase BLM is involved in the DNA damage response, DNA metabolism, and genetic stability. Loss of function mutations in BLM cause the genetic instability/cancer predisposition syndrome Bloom syndrome. However, the molecular mechanism underlying the regulation of BLM in cancers remains largely elusive. Here, we demonstrate that the deubiquitinating enzyme USP37 interacts with BLM and that USP37 deubiquitinates and stabilizes BLM, thereby sustaining the DNA damage response (DDR). Mechanistically, DNA double-strand breaks (DSB) promotes ATM phosphorylation of USP37 and enhances the binding between USP37 and BLM. Moreover, knockdown of USP37 increases BLM polyubiquitination, accelerates its proteolysis, and impairs its function in DNA damage response. This leads to enhanced DNA damage and sensitizes breast cancer cells to DNA-damaging agents in both cell culture and in vivo mouse models. Collectively, our results establish a novel molecular mechanism for the USP37-BLM axis in regulating DSB repair with an important role in chemotherapy and radiotherapy response in human cancers.

Targeting NUPR1 for Cancer Treatment: A Risky Endeavor

NUPR1 is a transcription factor that has attracted great attention because of its various roles in cancer. Several studies were carried out to determine its molecular targets and mechanism of action to develop novel therapies against cancer. Here, we shed light on the role of NUPR1 in different types of cancer. NUPR1 regulates a complex network of pathways that may be affected by its silencing, which can cause varying effects. Its role in some types of cancer has been reported but remains incompletely understood, whereas its roles in other types of cancers have not been reported yet. Therefore, targeting NUPR1 for cancer treatment remains challenging and risky.

Sirt5 Attenuates Cisplatin-Induced Acute Kidney Injury through Regulation of Nrf2/HO-1 and Bcl-2

Cisplatin- (CDDP) induced acute kidney injury (AKI) limits the clinical use of cisplatin. Several sirtuin (SIRT) family proteins are involved in AKI, while the roles of Sirt5 in cisplatin-induced AKI remain unknown. In the present study, we characterized the role and mechanism of Sirt5 in cisplatin-induced apoptosis using the human kidney 2 (HK-2) cell line. CDDP treatment decreased Sirt5 expression of HK-2 cells in a dose-dependent manner. In addition, Sirt5 overexpression enhanced the metabolic activity in CDDP-treated HK-2 cells while Sirt5 siRNA attenuated it. Forced expression of Sirt5 inhibited CDDP-induced apoptosis while Sirt5 siRNA showed the opposite effects. Accordingly, Sirt5 overexpression inhibited the level of caspase 3 cleavage and cytochrome c levels. Furthermore, we found that Sirt5 increased mitochondrial membrane potentials and ameliorated intracellular ROS production. Mitotracker Red staining indicated that Sirt5 overexpression was able to maintain the mitochondrial density during CDDP treatment. We also investigated possible downstream targets of Sirt5 and found that Sirt5 increased Nrf2, HO-1, and Bcl-2 while it decreased Bax protein expression. Sirt5 siRNA showed the opposite effect on these proteins. The levels of Nrf2, HO-1, and Bcl-2 proteins in HK-2 cells were also decreased after CDDP treatment. Moreover, Nrf2 and Bcl-2 siRNA partly abolished the protecting effect of Sirt5 on CDDP-induced apoptosis and cytochrome c release. Catalase inhibitor 3-AT also abolished the cytoprotective effect of Sirt5. Together, the results demonstrated that Sirt5 attenuated cisplatin-induced apoptosis and mitochondrial injury in human kidney HK-2 cells, possibly through the regulation of Nrf2/HO-1 and Bcl-2.

Bloom Syndrome Protein Activates AKT and PRAS40 in Prostate Cancer Cells

Purpose

Prostate cancer (PC) is a common malignant tumor and a leading cause of cancer-related death in men worldwide. In order to design new therapeutic interventions for PC, an understanding of the molecular events underlying PC tumorigenesis is required. Bloom syndrome protein (BLM) is a RecQ-like helicase, which helps maintain genetic stability. BLM dysfunction has been implicated in tumor development, most recently during PC tumorigenesis. However, the molecular basis for BLM-induced PC progression remains poorly characterized. In this study, we investigated whether BLM modulates the phosphorylation of an array of prooncogenic signaling pathways to promote PC progression.

Methods

We analyzed differentially expressed proteins (DEPs) using iTRAQ technology. Site-directed knockout of BLM in PC-3 prostate cancer cells was performed using CRISPR/Cas9-mediated homologous recombination gene editing to confirm the effects of BLM on DEPs. PathScan® Antibody Array Kits were used to analyze the phosphorylation of nodal proteins in PC tissue. Immunohistochemistry and automated western blot (WES) analyses were used to validate these findings.

Results

We found that silencing BLM in PC-3 cells significantly reduced their proliferative capacity. In addition, BLM downregulation significantly reduced levels of phosphorylated protein kinase B (AKT (Ser473)) and proline-rich AKT substrate of 40 kDa (PRAS40 (Thr246)), and this was accompanied by enhanced ROS (reactive oxygen species) levels. In addition, we found that AKT and PRAS40 inhibition reduced BLM, increased ROS levels, and induced PC cell apoptosis.

Conclusions

We demonstrated that BLM activates AKT and PRAS40 to promote PC cell proliferation and survival. We further propose that ROS act in concert with BLM to facilitate PC oncogenesis, potentially via further enhancing AKT signaling and downregulating PTEN expression. Importantly, inhibiting the BLM-AKT-PRAS40 axis induced PC cell apoptosis. Thus, we highlight new avenues for novel anti-PC treatments.

Evaluation of Polymer Nanoformulations in Hepatoma Therapy by Established Rodent Models

Hepatoma is one of the most severe malignancies usually with poor prognosis, and many patients are insensitive to the existing therapeutic agents, including the drugs for chemotherapy and molecular targeted therapy. Currently, researchers are committed to developing the advanced formulations with controlled drug delivery to improve the efficacy of hepatoma therapy. Numerous inoculated, induced, and genetically engineered hepatoma rodent models are now available for formulation screening. However, animal models of hepatoma cannot accurately represent human hepatoma in terms of histological characteristics, metastatic pathways, and post-treatment responses. Therefore, advanced animal hepatoma models with comparable pathogenesis and pathological features are in urgent need in the further studies. Moreover, the development of nanomedicines has renewed hope for chemotherapy and molecular targeted therapy of advanced hepatoma. As one kind of advanced formulations, the polymer-based nanoformulated drugs have many advantages over the traditional ones, such as improved tumor selectivity and treatment efficacy, and reduced systemic side effects. In this article, the construction of rodent hepatoma model and much information about the current development of polymer nanomedicines were reviewed in order to provide a basis for the development of advanced formulations with clinical therapeutic potential for hepatoma.