BackgroundPituitary adenylate cyclase-activating polypeptide (PACAP) 38 is an endogenous neuropeptide with diverse functions, notably its critical role in inhibiting tumor proliferation. Radiotherapy is an important step in the standard treatment modality of many tumors. Combining radiotherapy with therapeutic agents represents a new and promising trend aimed at enhancing radiation sensitivity and improving tumor treatment efficacy. However, the efficacy of PACAP38 combined with radiotherapy on tumors has not yet been studied.ObjectiveThis study aimed to investigate the impact of PACAP38, both independently and in combination with irradiation, on glioma and breast cancer cells, while elucidating the underlying mechanisms involved.MethodsWe investigated the impact of PACAP38 independently and combined it with irradiation on glioma and breast cancer cells in vitro through cell counting kit-8, clonogenic formation, Edu assays, and in vivo through a xenograft tumor model. We further explored the molecular mechanisms underlying the inhibitory effects of PACAP38 on tumors using RNA sequencing, western blotting assay, immunohistochemistry, and immunofluorescence analysis. Further investigation of gene function and the downstream mechanism was carried out through small interfering RNA and overexpression lentivirus targeting the SRY-related high-mobility group box 6 (SOX6) gene and western blotting assay.ResultsOur findings revealed that PACAP38 could effectively synergize with radiation to suppress the proliferation of glioma and breast cancer cells in vivo and in vitro. Molecular studies revealed that the inhibitory effect of PACAP38 on tumor cell proliferation was mediated by upregulating SOX6 protein expression through histone acetylation, thereby inhibiting the Wnt-β-catenin signaling pathway.ConclusionPACAP38 synergizes with irradiation to suppress the proliferation of multiple cancer cells via regulating SOX6/Wnt/β-catenin signaling. This combination may represent a promising therapeutic strategy for cancer treatment, potentially improving outcomes for patients undergoing radiotherapy.

Some breast cancer patients with overexpression of human epidermal growth factor receptor 2 need both chest radiotherapy and targeted therapy with trastuzumab (TRZ). The cardiotoxicity associated with combined treatment potentially restricts the clinical benefits of antitumor therapy. There is no consensus on whether and how chest radiotherapy can be given in concurrent with TRZ at present, considering the cardiotoxicity. This study intends to establish an in vitro and in vivo heart injury model by irradiation and TRZ, analyze whether there is a synergistic effect in heart, and to explore the molecular changes. First, an in vitro irradiation model of H9C2 cardiomyocytes was established. The effects of TRZ and radiation on cardiomyocyte injury were observed by cell flow cytometry, CCK-8 test, Western blot, γ-H2AX fluorescence focus formation and cell Reactive Oxygen Species (ROS) content test. Second, the mouse heart injury model was set up by X-ray cardiac irradiation combined with TRZ. Six months later, the cardiac function was analyzed by small animal ultrasound and 18FDG-micro PET/CT. The morphological changes of heart tissue were assessed by histological section. We found that concurrent TRZ aggravates the injury effect of irradiation on cardiomyocytes in vitro. The influence of TRZ might be consequence of inhibiting Akt phosphorylation, promoting the excessive accumulation of ROS in cells and promoting intracellular DNA damage. In animal experiments, the dysfunction of diastolic and myocardial ischemia of mouse heart was observed by echocardiography and 18FDG-micro PET/CT, respectively; myocardial fibrosis and cardiomyocyte apoptosis were also observed. Therefore, our in vitro and in vivo experiments have revealed that TRZ combined irradiation caused more cardiotoxicity than irradiation or TRZ alone. These results suggested that the concurrent management of TRZ and radiotherapy should be carefully made in clinical practice, and more attention is needed on cardiac safety.

Astragaloside II (AS II), a novel saponin purified from Astragalus membranes, has been reported to modulate the immune response, repair tissue injury, and prevent inflammatory response. However, the protective effects of AS II on podocyte injury in diabetic nephropathy (DN) have not been investigated yet. In this study, we aimed to investigate the beneficial effects of AS II on podocyte injury and mitochondrial dysfunction in DN. Diabetes was induced with streptozotocin (STZ) by intraperitoneal injection at 55 mg/kg in rats. Diabetic rats were randomly divided into four groups, namely, diabetic rats and diabetic rats treated with losartan (10 mg·kg−1·d−1) or AS II (3.2 and 6.4 mg·kg−1·d−1) for 9 weeks. Normal Sprague-Dawley rats were chosen as nondiabetic control group. Urinary albumin/creatinine ratio (ACR), biochemical parameters, renal histopathology and podocyte apoptosis, and morphological changes were evaluated. Expressions of mitochondrial dynamics-related and autophagy-related proteins, such as Mfn2, Fis1, P62, and LC3, as well as Nrf2, Keap1, PINK1, and Parkin, were examined by immunohistochemistry, western blot, and real-time PCR, respectively. Our results indicated that AS II ameliorated albuminuria, renal histopathology, and podocyte foot process effacement and podocyte apoptosis in diabetic rats. AS II also partially restored the renal expression of mitochondrial dynamics-related and autophagy-related proteins, including Mfn2, Fis1, P62, and LC3. AS II also increased the expression of PINK1 and Parkin associated with mitophagy in diabetic rats. Moreover, AS II facilitated antioxidative stress ability via increasing Nrf2 expression and decreasing Keap1 protein level. These results suggested that AS II ameliorated podocyte injury and mitochondrial dysfunction in diabetic rats partly through regulation of Nrf2 and PINK1 pathway. These important findings might provide an innovative therapeutic strategy for the treatment of DN.

BRCA1-BARD1 heterodimers act in multiple steps during homologous recombination (HR) to ensure the prompt repair of DNA double strand breaks. Dysfunction of the BRCA1 pathway enhances the therapeutic efficiency of poly-(ADP-ribose) polymerase inhibitors (PARPi) in cancers, but the molecular mechanisms underlying this sensitization to PARPi are not fully understood. Here, we show that cancer cell sensitivity to PARPi is promoted by the ring between ring fingers (RBR) protein RNF19A. We demonstrate that RNF19A suppresses HR by ubiquitinating BARD1, which leads to dissociation of BRCA1-BARD1 complex and exposure of a nuclear export sequence in BARD1 that is otherwise masked by BRCA1, resulting in the export of BARD1 to the cytoplasm. We provide evidence that high RNF19A expression in breast cancer compromises HR and increases sensitivity to PARPi. We propose that RNF19A modulates the cancer cell response to PARPi by negatively regulating the BRCA1-BARD1 complex and inhibiting HR-mediated DNA repair.

Multiple studies have highlighted the importance of long noncoding RNAs in tumorigenesis. However, the molecular mechanisms underlying the role of lncRNAs in breast cancer are not well understood. Recently, the lncRNA HOXC-AS3 has drawn significant attention due to its regulatory effects on the tumorigenesis of human cancers. However, the potential molecular mechanisms whereby it mediates breast cancer progression remain unknown. Based on public breast cancer expression data and using bioinformatics methods, we discovered significantly upregulated expression levels of HOXC-AS3 in diseased tissues. We verified this result in breast cancer samples and found that the expression of HOXC-AS3 was well correlated with the prognosis of breast cancer. In vitro and in vivo experimental evidence suggests that HOXC-AS3 has the potential to regulate tumorigenesis. Further, mechanistic studies demonstrated the potential of HOXC-AS3 in the transcriptional activation of TK1 via its binding to YBX1. Furthermore, the silencing of TK1 reversed HOXC-AS3-mediated increase in breast cancer cell growth and migration. In conclusion, these results indicated the potential value of HOXC-AS as a prognostic biological marker for breast cancer, and possibly, as a therapeutic target.

Diabetic kidney disease (DKD) is a major cause of end-stage renal disease (ESRD), and therapeutic strategies for delaying its progression are limited. Loss of podocytes by apoptosis characterizes the early stages of DKD. To identify novel therapeutic options, we investigated the effects of Xuesaitong (XST), consisting of total saponins from Panax notoginseng, on podocyte apoptosis in streptozotocin- (STZ-) induced diabetic rats. XST (5 mg/kg·d) or Losartan (10 mg/kg·d) was given to diabetic rats for 12 weeks. Albuminuria, renal function markers, and renal histopathology morphological changes were examined. Podocyte apoptosis was determined by triple immunofluorescence labelling including a TUNEL assay, WT1, and DAPI. Renal expression of Nox4, miRNA-214, PTEN, PDK1, phosphorylated Akt, mTOR, and mTORC1 was detected. In diabetic rats, severe hyperglycaemia and albuminuria developed, and apoptotic podocytes were markedly increased in diabetic kidneys. However, XST attenuated albuminuria, mesangial expansion, podocyte apoptosis, and morphological changes of podocytes in diabetic rats. Decreased expression of PTEN, as well as increased expression of Nox4, miRNA-214, PDK1, phosphorylated Akt, mTOR, and mTORC1, was detected. These abnormalities were partially restored by XST treatment. Thus, XST ameliorated podocyte apoptosis partly through modulating the PTEN-PDK1-Akt-mTOR pathway. These novel findings might point the way to a natural therapeutic strategy for treating DKD.

Diabetic kidney disease (DKD) is an important diabetic microvascular complication, which has become the main cause of end-stage renal disease (ESRD) all over the world. It is of great significance to find effective therapeutic targets and improve the prognosis of the disease. Traditionally, it is believed that the activation of the renin–angiotensin–aldosterone system (RAAS) is the main reason for the progression of DKD, but with the progress of research, it is known that the production of proteinuria in patients with DKD is also related to podocyte injury and loss. Many studies have shown that mitochondrial dysfunction in podocytes plays an important role in the occurrence and development of DKD, and oxidative stress is also the main pathway and common hub of diabetes to the occurrence and development of microvascular and macrovascular complications. Thus, the occurrence and progression of DKD is correlated with not only the activation of the RAAS, but also the damage of mitochondria, oxidative stress, and inflammatory mediators. Besides, diabetes-related metabolic disorders can also cause abnormalities in mitochondrial dynamics, autophagy and cellular signal transduction, which are intertwined in a complex way. Therefore, in this review, we mainly explore the mechanism and the latest research progress of podocyte mitochondria in DKD and summarize the main signal pathways involved in them. Thus, it provides feasible clinical application and future research suggestions for the prevention and treatment of DKD, which has important practical significance for the later treatment of patients with DKD.

Cardiac toxicity is one of the major advese effect associated with thoracic irradiation. Breast cancer patients with human epidermal factor receptor-2 (Her-2) overexpression could be indicated for both radiation and anti-Her2 target therapy. We aimed to investigate the early detection of radiation and Trastuzumab (TRZ) induced acute cardiotoxicity in mice. In the present study, the heart of animal was subjected to irradiation (IR, 14 Gy/1 Fx), TRZ was intraperitonealy (i.p.) administrated to mice in 2 weeks (6 fractions). The IR plus TRZ group received heart IR after TRZ. We found that body weight of mouse in treatment groups reduced significantly as compared with that of mouse in control group (P<0.05). At day 21, the diastolic function of mice decreased significantly in IR plus TRZ group compared with control group measured by E/E' parameter using echocardiography (57.72 vs 40.82, P<0.05). The left ventricular posterior wall (LVPW) and interventricular septum (IVS) were also increased significantly in diastolic phase at day 21 in the combined group compared with TRZ alone (LVPW: 0.95 mm vs 0.70 mm, P<0.05; IVS: 0.94 mm vs 0.65 mm P<0.05). Moreover, hematoxylin and eosin (HE) staining of cardiac tissue showed that the arrangement of myocardial cell was disordered in the combined group with vacuolar and adipocyte changes, as well as the loose of structure of myocardial cells and the pyknosis of the nucleus. Moderate damage was observed in irradiation-treated group and TRZ-treated group. The expressions of γ-H2AX, vascular cell adhesion molecule-1 (VCAM-1) and von Willebrand Factor (vWF) were remarkedly appeared in co-treatment group. Heart irradiation combined with TRZ treatment simultaneously might cause acute cardiac toxicity in terms of the parameter of E/E', LVPW and IVS. Our results suggest that the diastolic function could detect the early stage of acute cardiotoxicity in heart exposed to irradiation and TRZ co-treatment in mice. The DNA injury and microangiopathy might involve in cardiac injury that aggravated by radiation and Trastuzumab treatments.