Scriptaid overcomes hypoxia-induced cisplatin resistance in both wild-type and mutant p53 lung cancer cells

BMP8B Activates Both SMAD2/3 and NF-κB Signals to Inhibit the Differentiation of 3T3-L1 Preadipocytes into Mature Adipocytes

Bone morphogenetic protein 8B (BMP8B) has been found to regulate the thermogenesis of brown adipose tissue (BAT) and the browning process of white adipose tissue (WAT). However, there is no available information regarding the role of BMP8B in the process of adipocyte differentiation. Here, we showed that BMP8B down-regulates transcriptional regulators PPARγ and C/EBPα, thereby impeding the differentiation of 3T3-L1 preadipocytes into fully mature adipocytes. BMP8B increased the phosphorylation levels of SMAD2/3, and TP0427736 HCl (SMAD2/3 inhibitor) significantly reduced the ability of BMP8B to inhibit adipocyte differentiation, suggesting that BMP8B repressed adipocyte differentiation through the SMAD2/3 pathway. Moreover, the knockdown of BMP I receptor ALK4 significantly reduced the inhibitory effect of BMP8B on adipogenesis, indicating that BMP8B triggers SMAD2/3 signaling to suppress adipogenesis via ALK4. In addition, BMP8B activated the NF-κB signal, which has been demonstrated to impede PPARγ expression. Collectively, our data demonstrated that BMP8B activates both SMAD2/3 and NF-κB signals to inhibit adipocyte differentiation. We provide previously unidentified insight into BMP8B-mediated adipogenesis.

Tumor microenvironment-regulating nanomedicine design to fight multi-drug resistant tumors

The tumor microenvironment (TME) is a very cunning system that enables tumor cells to escape death post-traditional antitumor treatments through the comprehensive effect of different factors, thereby leading to drug resistance. Deep insights into TME characteristics and tumor resistance encourage the construction of nanomedicines that can remodel the TME against drug resistance. Tremendous interest in combining TME-regulation measurement with traditional tumor treatment to fight multidrug-resistant tumors has been inspired by the increasing understanding of the role of TME reconstruction in improving the antitumor efficiency of drug-resistant tumor therapy. This review focuses on the underlying relationships between specific TME characteristics (such as hypoxia, acidity, immunity, microorganisms, and metabolism) and drug resistance in tumor treatments. The exciting antitumor activities strengthened by TME regulation are also discussed in-depth, providing solutions from the perspective of nanomedicine design. This article is categorized under: Therapeutic Approaches and Drug Discovery > Emerging Technologies Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Study on the Predictive Value of P53 Protein Expression in Brain Metastasis in NSCLC and the Mechanism of miR-424 Reversing Platinum Resistance in NSCLC

In order to analyze the predictive value of P53 protein expression in brain metastases in NSCLC and the mechanism of miR-424 reversing platinum resistance in NSCLC, a retrospective analysis is conducted in this study. Eighty-two NSCLC patients who received relevant diagnosis and treatment in our hospital from September 2020 to September 2021 are chosen. The prognosis of the patients is observed, and the patients were divided into two groups according to the occurrence of BMS. The comparison of clinical baseline data and the expression of P53 protein and miR-424 after surgery are performed. Furthermore, the predictive value of the P53 protein gene on the occurrence of BMS in NSCLC is analyzed by the ROC curve, and the expression of miR-424 in serum of the patients before and after drug resistance is compared. The results demonstrate that the expression of P53 protein has a high predictive value for predicting the occurrence of BRAIN metastases in NSCLC patients. Also, the high expression of miR-424 suggests that it is closely related to the occurrence of platinum resistance in NSCLC patients.

FE65 in breast cancer and its clinicopathological significance

BACKGROUND

Transcription coregulator adapter protein FE65 is well known to play pivotal roles in pathogenesis of Alzheimer's disease by regulating amyloid precursor protein (APP) expression and processing. APP was recently reported to be also involved in development of human malignancies. Therefore, in this study, we studied FE65 status in different subtypes of human breast cancer and correlated the results with cell proliferation and migration of carcinoma cells and clinicopathological features of breast cancer patients to explore its biological and clinical significance in breast cancer.

METHODS

We first immunolocalized FE65 and APP in 138 breast cancer patients and correlated the results with their tumor grade. Then, we did further exploration by proximity ligation assay, WST-8, and wound-healing assay.

RESULTS

FE65 immunoreactivity in carcinoma cells was significantly associated with lymph-node metastasis, ERα, and high pathological N factor. APP immunoreactivity was significantly positively correlated with high pathological N factor. FE65, APP, and p-APP were all significantly correlated with shorter disease-free survival of breast cancer patients. In addition, the status of FE65 was significantly associated with overall survival. Results of in vitro analysis revealed that FE65 promoted the migration and proliferation of T-47D and ZR-75-1 breast carcinoma cells. In situ proximity ligation assay revealed that FE65 could bind to APP in the cytoplasm. FE65 was also associated with APP and ERα in carcinoma cells, suggesting their cooperativity in promoting carcinoma cell proliferation and migration. APP was also significantly associated with adverse clinical outcome of the patients.

CONCLUSIONS

This is the first study to explore the clinical significance of FE65 in human breast cancer. The significant positive correlation of FE65 with poor clinical outcome, direct binding to APP, and promotion of carcinoma cell proliferation and migration indicated that FE65-APP pathway could serve as the potential candidate of therapeutic intervention in breast cancer patients.

Tumor hypoxia: The major culprit behind cisplatin resistance in cancer patients

Cisplatin is the most commonly used first-line drug for cancer treatment. However, many patients develop resistance to cisplatin therapy which ultimately results in therapy failure and increased mortality. A growing body of evidence shows that the hypoxic microenvironment is the prime factor underlying tumor insensitivity to cisplatin treatment. Since tumors in the majority of cancer patients are under hypoxic stress (low oxygen supply), it becomes necessary to understand the pathobiology behind hypoxia-induced cisplatin resistance in cancer cells. Here, we discuss the molecular events that render hypoxic tumors insensitive to cisplatin therapy. Furthermore, various drugs and tumor oxygenation techniques have been developed to circumvent cisplatin resistance in hypoxic tumors. However, their pharmaceutical applications are limited due to failures in clinical investigations and a lack of preclinical studies in the hypoxic tumor microenvironment. This review addresses these challenges and provides new directions for the strategic deployment of cisplatin sensitizers in the hypoxic tumor microenvironment.

RAD51 is a potential marker for prognosis and regulates cell proliferation in pancreatic cancer

BACKGROUND

The DNA damage and repair pathway is considered a promising target for developing strategies against cancer. RAD51, also known as RECA, is a recombinase that performs the critical step in homologous recombination. RAD51 has recently received considerable attention due to its function in tumor progression and its decisive role in tumor resistance to chemotherapy. However, its role in pancreatic cancer has seldom been investigated. In this report, we provide evidence that RAD51, regulated by KRAS, promotes pancreatic cancer cell proliferation. Furthermore, RAD51 regulated aerobic glycolysis by targeting hypoxia inducible factor 1α (HIF1α).

METHODS

TCGA (The Cancer Genome Atlas) dataset analysis was used to examine the impact of RAD51 expression on overall survival of pancreatic cancer patients. Lentivirus-mediated transduction was used to silence RAD51 and KRAS expression. Quantitative real-time PCR and western blot analysis validated the efficacy of the knockdown effect. Analysis of the glycolysis process in pancreatic cancer cells was also performed. Cell proliferation was determined using a CCK-8 (Cell Counting Kit-8) proliferation assay.

RESULTS

Pancreatic cancer patients with higher levels of RAD51 exhibited worse survival. In pancreatic cancer cells, RAD51 positively regulated cell proliferation, decreased intracellular reactive oxygen species (ROS) production and increased the HIF1α protein level. KRAS/MEK/ERK activation increased RAD51 expression. In addition, RAD51 was a positive regulator of aerobic glycolysis.

CONCLUSION

The present study reveals novel roles for RAD51 in pancreatic cancer that are associated with overall survival prediction, possibly through a mechanism involving regulation of aerobic glycolysis. These findings may provide new predictive and treatment targets for pancreatic cancer.

Evaluation of the Betulinic Acid-Cisplatin conjugate APC and its precursor DE9B for the treatment of human malignant glioma

Despite the existence of multimodal therapy concepts, glioblastoma remains a tumor type with one of the worst prognoses. In particular, the poor prognosis is due to the lack of therapeutic efficacy of chemical agents and irradiation in hypoxic tumor areas. New therapeutic strategies could improve the treatment of glioblastoma. In this study, we investigated the therapeutic efficacy of a conjugate of cisplatin (DDP), a widely used chemotherapeutic agent, and betulinic acid (BA), a natural product from plane tree bark, in glioblastoma cells under different oxygen conditions. We investigated the effects of the BA-DDP conjugate κN',N''-{3-acetyloxy-BA-28-[2-(2-aminoethyl)aminoethyl]amide} dichlorido platinum(II) (APC) and its precursor 3-acetyloxy-BA-28-[2-(2-aminoethyl)aminoethyl]amide (DE9B) on cytotoxicity, cell growth, apoptosis, migration and radiosensitivity compared to BA or DDP alone under different oxygen conditions. Based on the EC₅₀ values, the precursor DE9B exhibited the strongest cytotoxic effects of the analyzed chemotherapeutic agents. The BA-DDP conjugate APC achieved a moderate cytotoxic effect in glioma cells. Both of the newly developed agents induced cell growth delay, apoptosis and inhibition of migration. Furthermore, additive effects could be achieved in combination with irradiation. In contrast to those of BA and DDP, the cell biological effects of APC and DE9B were not influenced by the oxygen concentration. In this study, the linking of BA and DDP did not produce a compound with additive therapeutic effects on glioblastoma cell lines in vitro. Nevertheless, the results of this study suggest that the precursor DE9B is an effective BA derivative for the treatment of glioblastoma in vitro.

Hypercapnic tumor microenvironment confers chemoresistance to lung cancer cells by reprogramming mitochondrial metabolism in vitro

The tumor microenvironment has previously been reported to be hypercapnic (as high as ~84 mmHg), although its effect on tumor cell behaviors is unknown. In this study, high CO₂ levels, ranging from 5% to 15%, protected lung cancer cells from anticancer agents, such as cisplatin, carboplatin and etoposide, by suppressing apoptosis. The cytoprotective effect of a high CO₂ level was independent of acidosis and was due to mitochondrial metabolic reprogramming that reduced mitochondrial respiration, as assessed by oxygen consumption, oxidative phosphorylation, mitochondrial membrane and oxidative potentials, eventually leading to reduced reactive oxidant species production. In contrast, high CO₂ levels did not affect cisplatin-mediated DNA damage responses or the expression of Bcl-2 family proteins. Although high CO₂ levels inhibited glycolysis, this inhibition was not mechanistically involved in high CO₂-mediated reductions in mitochondrial respiration, because a high CO₂ concentration inhibited isolated mitochondria. A cytoprotective effect of high CO₂ levels on mitochondria DNA-depleted cells was not noted, lending support to our conclusion that high CO₂ levels act on mitochondria to reduce the cytotoxicity of anticancer agents. High CO₂-mediated cytoprotection was also noted in a 3D culture system. In conclusion, the hypercapnic tumor microenvironment reprograms mitochondrial respiratory metabolism causing chemoresistance in lung cancer cells. Thus, tumor hypercapnia may represent a novel target to improve chemosensitivity.

Epigenetic agents in combined anticancer therapy

In the last decade, epigenetic drugs (such as inhibitors of DNA methyltransferases and histone deacetylases) have been intensively used for cancer treatment. Their applications have shown high anticancer effectivity and tolerable side effects. However, they are unfortunately not effective in the treatment of some types and phenotypes of cancers. Nevertheless, several studies have demonstrated that problems of drug efficacy can be overcome through the combined application of therapeutic modulates. Therefore, combined applications of epigenetic agents with chemotherapy, radiation therapy, immunotherapy, oncolytic virotherapy and hyperthermia have been presented. This review summarizes and discusses the general principles of this approach, as introduced and supported by numerous examples. In addition, predictions of the future potential applications of this methodology are included.

Mxd1 mediates hypoxia-induced cisplatin resistance in osteosarcoma cells by repression of the PTEN tumor suppressor gene

Hypoxia-induced chemoresistance remains a major obstacle to treating osteosarcoma effectively. Mxd1, a member of the Myc/Max/Mxd family, was shown to be involved in the development of drug resistance under hypoxia. However, the effect of Mxd1 on hypoxia-induced cisplatin (CDDP) resistance and its mechanism in osteosarcoma have not been fully elucidated. In this study, we demonstrated that HIF-1α-induced Mxd1 contributed to CDDP resistance in hypoxic U-2OS and MG-63 cells. The knockdown of Mxd1 expression elevated PTEN expression at both protein and RNA levels in these hypoxic cells. Using Luciferase reporter and ChIP assays, we confirmed that Mxd1 directly bound to the E-box sites within the PTEN promoter region. We further demonstrated that PTEN knockdown decreased CDDP sensitivity in Mxd1 siRNA-transfected U-2OS and MG-63 cells under hypoxia. Our results also showed that Mxd1 deficiency in hypoxic U-2OS and MG-63 cells lead to inactivation of PI3K/AKT signaling, which is the downstream of PTEN. Furthermore, blockade of PI3K/AKT signal re-sensitized hypoxic U-2OS and MG-63 cells to CDDP. Taken together, these findings suggest that HIF-1α-induced Mxd1 up-regulation suppresses the expression of PTEN under hypoxia, which leads to the activation of PI3K/AKT antiapoptotic and survival pathway. As a result CDDP resistance in osteosarcoma cells is induced.

Up-regulation of IRF-3 expression through GATA-1 acetylation by histone deacetylase inhibitor in lung adenocarcinoma A549 cells

Interferon regulatory factor 3 (IRF-3) is an important transcription factor for interferon genes. Although its functional activation by viral infection has been widely explicated, the regulatory mechanism of IRF-3 gene expression in cancer cells is poorly understood. In this study, we demonstrated treatment of lung adenocarcinoma A549 cells with trichostatin A (TSA) and valproic acid (VPA), two different classes of histone deacetylase inhibitors, strongly stimulated IRF-3 gene expression. Truncated and mutated IRF-3 promoter indicated that a specific GATA-1 element was responsible for TSA-induced activation of IRF-3 promoter. Chromatin immunoprecipitation and electrophoretic mobility shift assay showed that TSA treatment increased the binding affinity of GATA-1 to IRF-3 promoter. Using immunoprecipitation assay and immunoblotting, we demonstrated that TSA increased the level of acetylated GATA-1 in A549 cells. In summary, our study implied that TSA enhanced IRF-3 gene expression through increased GATA-1 recruitment to IRF-3 promoter and the acetylation level of GATA-1 in lung adenocarcinoma A549 cells.

Berberine Reverses Hypoxia-induced Chemoresistance in Breast Cancer through the Inhibition of AMPK- HIF-1α

Breast cancer is the most common type of cancer and the second leading cause of cancer death in American women. Chemoresistance is common and inevitable after a variable period of time. Therefore, chemosensitization is a necessary strategy on drug-resistant breast cancer. In this study, MCF-7 breast cancer cell was cultured under hypoxia for a week to induce the resistance to doxorubincin (DOX). The effect of different doses of berberine, a traditional Chinese medicine, on DOX sensitivity to MFC-7/hypoxia cells was observed. We found that hypoxia increased DOX resistance on breast cancer cells with the AMPK activation. Low-dose berberine could resensitize DOX chemosensitivity in MCF-7/hypoxia cell, however, high-dose berberine directly induced apoptosis. The intriguing fact was that the protein expressions of AMPK and HIF-1α were down-regulated by berberine, either low dose or high dose. But the downstream of HIF-1α occurred the bifurcation dependent on the dosage of berberine: AMPK-HIF-1α-P-gp inactivation played a crucial role on the DOX chemosensitivity of low-dose berberine, while AMPK-HIF-1α downregulaton inducing p53 activation led to apoptosis in high-dose berberine. These results were consistent to the transplanted mice model bearing MCF-7 drug-resistance tumor treated by berberine combined with DOX or high-dose berberine alone. This work shed light on a potentially therapeutic attempt to overcome drug-resistant breast cancer.

Pinus massoniana bark extract inhibits migration of the lung cancer A549 cell line

The bark of Pinus massoniana is a traditional Chinese medicine for the treatment of various health disorders. Previous studies have demonstrated that P. massoniana bark extract (PMBE) may induce the apoptosis of hepatoma and cervical cancer cells. However, whether PMBE is able to inhibit the migration of lung cancer cells requires further investigation. In the current study, the effects of PMBE on the viability of human lung cancer A549 cells were detected using an MTT assay. The migration of lung cancer cells following exposure to PMBE were quantified using wound healing and Transwell assays, respectively. The expression levels of matrix metalloproteinase (MMP)-9 were determined using western blotting. The results revealed that PMBE significantly inhibited the growth of the lung cancer cells. In addition, the wound closure rate and the migration of the lung cancer cells were suppressed by PMBE. Furthermore, the expression levels of MMP-9 were reduced. These findings indicated that PMBE is able to restrict the migration and invasion of lung cancer cells, and that PMBE may serve as a novel therapeutic agent for patients with metastatic lung cancer in the future.