Current Cancer Drug Targets - Volume 23, Issue 2, 2023

Evidence shows that there is a synergistic, bidirectional association between cancer and aging with many shared traits. Age itself is a risk factor for the onset of most cancers, while evidence suggests that cancer and its treatments might accelerate aging by causing genotoxic and cytotoxic insults. Aging has been associated with a series of alterations that can be linked to cancer: i) genomic instability caused by DNA damage or epigenetic alterations coupled with repair errors, which lead to progressive accumulation of mutations; ii) telomere attrition with possible impairment of telomerase, shelterin complex, or the trimeric complex (Cdc13, Stn1 and Ten1 - CST) activities associated with abnormalities in DNA replication and repair; iii) altered proteostasis, especially when leading to an augmented proteasome, chaperon and autophagy-lysosome activity; iv) mitochondrial dysfunction causing oxidative stress; v) cellular senescence; vi) stem cells exhaustion, intercellular altered communication and deregulated nutrient sensing which are associated with microenvironmental modifications which may facilitate the subsequential role of cancer stem cells. Nowadays, anti-growth factor agents and epigenetic therapies seem to assume an increasing role in fighting aging-related diseases, especially cancer. This report aims to discuss the impact of age on cancer growth.

Background: Cancer stem-like cells in triple-negative breast cancer (TNBC-SLCs) are the tumorigenic core for malignancy. Aberrant expression of the RON receptor tyrosine kinase has implications in TNBC tumorigenesis and malignancy. Objective: In this study, we identified the RON receptor as a pathogenic factor contributing to TNBC cell stemness and validated anti-RON antibody-drug conjugate Zt/g4-MMAE for eradication of RONexpressing TNBC-SLCs. Methods: Immunofluorescence and Western blotting were used for analyzing cellular marker expression. TNBC-SLCs were isolated by magnetic-immunofluorescence cell-sorting techniques. Spheroids were generated using the ultralow adhesion culture methods. Levels of TNBC-SLC chemosensitivity were determined by MTS assays. TNBC-SLC mediated tumor growth was determined in athymic nude mice. The effectiveness of Zt/g4-induced RON internalization was measured by immunofluorescence analysis. Efficacies of Zt/g4-MMAE in killing TNBC-SLCs in vitro and in eradicating TNBC-SLCmediated tumors were determined in mouse models. All data were statistically analyzed using the GraphPad Prism 7 software. Results: Increased RON expression existed in TNBC-SLCs with CD44+/CD24- phenotypes and ALDH activities and facilitated epithelial to mesenchymal transition. RON-positive TNBC-SLCs enhanced spheroid-formatting capability compared to RON-negative TNBC-SLCs, which were sensitive to small molecule kinase inhibitor BMS-777607. Increased RON expression also promoted TNBC-SLC chemoresistance and facilitated tumor growth at an accelerated rate. In vitro, Zt/g4-MMAE caused massive TNBC-SLC death with an average IC50 value of ~1.56 μg per/ml and impaired TNBC cell spheroid formation. In mice, Zt/g4-MMAE effectively inhibited and/or eradicated TNBC-SLC mediated tumors in a single agent regimen. Conclusion: Sustained RON expression contributes to TNBC-SLC tumorigenesis. Zt/g4-MMAE is found to be effective in vivo in killing TNBC-SLC-mediated xenograft tumors. Our findings highlight the feasibility of Zt/g4-MMAE for the eradication of TNBC-SLCs in the future.

Background: Breast cancer (BC) has a complex and heterogeneous etiology, and the emergence of resistance to conventional chemo-and radiotherapy results in unsatisfactory outcomes during BC treatment. Targeted nanomedicines have tremendous therapeutic potential in BC treatment over their free drug counterparts. Objective: Hence, this study aimed to evaluate the newly fabricated pH-sensitive multifunctional FAHA- Amygdalin@Fe2O3 nano-core-shell composite (AF nanocomposite) and/or γ-radiation for effective localized BC therapy. Methods: The physicochemical properties of nanoparticles were examined, including stability, selectivity, responsive release to pH, cellular uptake, and anticancer efficacy. MCF-7 and MDA-MB-231 cells were treated with AF at the determined IC50 doses and/or exposed to γ-irradiation (RT) or were kept untreated as controls. The antitumor efficacy of AF was proposed via assessing anti-proliferative effects, cell cycle distribution, apoptosis, and determination of the oncogenic effectors. Results: In a bio-relevant medium, AF nanoparticles demonstrated extended-release characteristics that were amenable to acidic pH and showed apparent selectivity towards BC cells. The bioassays revealed that the HA and FA-functionalized AF markedly hindered cancer cell growth and enhanced radiotherapy (RT) through inducing cell cycle arrest (pre-G1 and G2/M) and increasing apoptosis, as well as reducing the tumorigenicity of BCs by inhibiting Silent information regulation factor 1 (SIRT1) and restoring p53 expression, deactivating the Yes-associated protein (YAP)/ Transcriptional coactivator with PDZ-binding motif (TAZ) signaling axis, and interfering with the tumor growth factor- β(TGF- β)/SMAD3 and HIF-1α/VEGF signaling hub while up-regulating SMAD7 protein expression. Conclusion: Collectively, the novel AF alone or prior RT abrogated BC tumorigenicity.

Aims: The study aims to explore new potential treatments for cervical cancer. Background: Cervical cancer is the second most common cancer in women, causing >250,000 deaths worldwide. Patients with cervical cancer are mainly treated with platinum compounds, which often cause severe toxic reactions. Furthermore, the long-term use of platinum compounds can reduce the sensitivity of cancer cells to chemotherapy and increase the drug resistance of cervical cancer. Therefore, exploring new treatment options is meaningful for cervical cancer. Objective: The present study was to investigate the effect of sildenafil on the growth and epithelial-tomesenchymal transition (EMT) of cervical cancer. Methods: HeLa and SiHa cells were treated with sildenafil for different durations. Cell viability, clonogenicity, wound healing, and Transwell assays were performed. The levels of transforming growth factor-β1 (TGF-β1), transforming growth factor-β type I receptor (TβRI), phosphorylated (p-) Smad2 and p-Smad3 in cervical cancer samples were measured. TGF-β1, Smad2 or Smad3 were overexpressed in HeLa cells, and we measured the expression of EMT marker proteins and the changes in cell viability, colony formation, etc. Finally, HeLa cells were used to establish a nude mouse xenograft model with sildenafil treatment. The survival rate of mice and the tumor size were recorded. Results: High concentrations of sildenafil (1.0-2.0 μM) reduced cell viability, the number of HeLa and SiHa colonies, and the invasion/migration ability of HeLa and SiHa cells in a dose- and time-dependent manner. The expression of TGF-β1, TβRI, p-Smad2 and p-Smad3 was significantly enhanced in cervical cancer samples and cervical cancer cell lines. Sildenafil inhibited the expression of TGF-β1-induced EMT marker proteins (Snail, vimentin, Twist, E-cadherin and N-cadherin) and p-Smad2/3 in HeLa cells. Overexpression of TGF-β1, Smad2, and Smad3 reversed the effect of sildenafil on EMT, viability, colony formation, migration, and invasion ability of HeLa cells. In the in vivo study, sildenafil significantly increased mouse survival rates and suppressed xenograft growth. Conclusion: Sildenafil inhibits the proliferation, invasion ability, and EMT of human cervical cancer cells by regulating the TGF-β1/Smad2/3 pathway.

Background: Chemotherapy is the common treatment for cervical cancer, and the occurrence of drug resistance seriously affects the therapeutic effect of cervical cancer. Our previous study found that PRKD2 mutations occurred only in cervical cancer patients with chemotherapy resistance. However, the relationship between PRKD2 and drug resistance of cervical cancer remains unknown. Objective: We aim to clarify the relationship between PRKD2 and drug resistance of cervical cancer. Methods: Samples of patient tumor tissue were collected before chemotherapy and sequenced by WES. Chemotherapy clinical response was determined by measuring tumor volume. The expression of PRKD2, cell viability, and apoptosis were assessed by qRT-PCR, Western blot, CCK8, and flow cytometry in SiHa and ME180 cells after transfected with siPRKD2. The chemotherapy sensitivity signaling- related proteins were analyzed by Western blot. The expression levels of PRKD2TP53, and CDKN1A in tissues were detected by immunohistochemistry staining. Results: The expression of PRKD2 was higher in chemotherapy-resistant cervical cancer patients. PRKD2 knockdown increased the chemotherapy sensitivity of cervical cancer cells via the TP53/CDKN1A pathway, which led to G1 arrest and cell apoptosis. Furthermore, downregulation of PRKD2 enhances chemotherapeutic sensitivity in cervical cancer patients through the TP53/CDKN1A pathway. Conclusion: In summary, PRKD2 may be a promising therapeutic target to improve the efficacy of chemotherapy.