Chapter seven--Cancer treatment with gene therapy and radiation therapy

Polymeric nanoparticles as a promising platform for treating triple-negative breast cancer: Current status and future perspectives

Triple-negative breast cancer (TNBC) is a highly aggressive subtype of breast cancer that lacks expression of estrogen, progesterone, and HER2 receptor targets for therapy. Polymeric nanoparticles help address the challenges in treating TNBC by enabling tailored and targeted drug delivery. Biocompatible polymeric nanoparticles leverage enhanced tumor permeability for site-specific accumulation and ligand-mediated active targeting to boost specificity. Controlled, sustained intratumorally release of encapsulated chemotherapies, such as paclitaxel and curcumin, improves antitumor efficacy as demonstrated through preclinical TNBC models. However, the practical application of these nanomedicines still has room for improvement. Advancing personalized nanoparticle platforms that align treatments to TNBC's expanding molecular subtypes shows promise. Expanding the polymer range through novel copolymers or drug conjugates may improve tumor penetration, stability, and drug encapsulation. Incorporating gene therapies, imaging agents, or triggering stimuli responsiveness into polymeric nanoparticles can also overcome innate and acquired drug resistance in TNBC while monitoring outcomes. This article reviews the different types of nanoparticles used to treat TNBC and the different mechanisms of nanoparticles that can deliver drugs to tumor cells. Collaboration across different disciplines aimed at developing combination therapies, immuno-oncology, tumor-targeting ligands, and translating preclinical safety/efficacy via scalable manufacturing practices is essential. Well-designed polymeric nanoparticles offer immense potential for patient-centric TNBC treatment, but continued optimization across bench to bedside efforts is critical for clinical realization and transforming patient outcomes.

Dissociative electron attachment to halogenated nucleotides: a quest for better radiosensitizers

Tumor hypoxia hampers radiotherapy efficacy, necessitating radiosensitizers. Substituted nucleobases offer advantages as radiosensitizers. They can be incorporated into DNA with minimal gene-expression alteration, selectively targeting tumor cells and having lower toxicity to normal tissues. They possess higher electron affinity than native DNA, facilitating rapid electron attachment for cancer-cell damage. Despite advancements, exploration beyond uracil nucleobases remains limited. Herein, we investigated electron attachment to potential radiosensitizers, specifically 5-halo-2'-deoxycytidine-3'-monophosphates (5X-3'-dCMPH). Our findings indicate that 5X-3'-dCMPH nucleotides possess higher electron affinity than unsubstituted 3'-dCMPH, suggesting halogenated nucleotides are better electron acceptors. Moreover, the high vertical detachment energy (VDE) implies minimal auto-detachment, and the dissociative electron attachment (DEA) pathways suggest that dehalogenation is the favored process for halogenated systems, supported by low dissociation barriers. Notably, 5Br-3'-dCMPH and 5I-3'-dCMPH exhibit nearly barrier-free dissociation after electron attachment, and thus, they may preferentially act as superior radiosensitizers.

Combined Effects of Annexin A5 Overexpression, 5-Fluorouracil Treatment, and Irradiation on Cell Viability of Caski Cervical Cancer Cell Line

Cervical cancer is the fourth leading cause of cancer deaths in women globally. Combining gene therapy with chemo- and radiotherapy may improve cervical cancer treatment outcomes. This study evaluated the effects of Annexin A5(ANXA5) overexpression alongside 5-fluorouracil (5-FU) and irradiation on the viability of CaSki cervical squamous cell carcinoma (SCC) cells. pAdenoVator-CMV-ANXA5-IRES-GFP-plasmid and mock plasmid were transfected into CaSki cells using calcium-phosphate. Seventy-two hours post-transfection, GFP expression was quantified by fluorescence microscopy and flow cytometry to evaluate transfection efficiency. ANXA5 overexpression was confirmed via qPCR. Twenty-four hours post-transfection, cells received a single dose of 8 Gy and were treated with 1 and 2 µg/ml of 5-FU (IC50 = 2.783 µg/ml). Cell viability, apoptosis, cell cycle stage, and Bcl-2 and Bax gene expression were assessed via MTT, annexin V/7-AAD, PI staining, and qPCR assays, respectively. ANXA5 was overexpressed 31.5-fold compared to control (p < 0.0001). MTT assays showed ANXA5 overexpression dose-dependently reduced CaSki cell viability (p < 0.001). IC50 of 5-FU was reduced from 2.783 μg/mL to 1.794 μg/mL when combined with ANXA5 overexpression. Additive effects on cell death were observed for ANXA5 plus 5-FU or irradiation versus ANXA5 alone. Apoptosis assays indicated combinatorial treatment increased CaSki cell apoptosis over ANXA5 alone. Cell cycle analysis revealed ANXA5 arrested cell cycle at G1/S phases; the percentage of cells in the S phase further rose with combination treatment. Finally, combination therapy significantly decreased Bcl-2 expression and increased Bax versus control (p < 0.001). Altogether, ANXA5 overexpression alongside 5-FU and irradiation may improve cervical squamous cell carcinoma (SCC) treatment efficacy. Further, in vivo investigations are warranted to confirm these in vitro results.

The role of viruses in cancer progression versus cancer treatment: A dual paradigm

Most human malignancies are attributed to exposure to infectious organisms such as viruses. Certain infections that can induce cancer can evade the immune system, leading to persistent inflammation that facilitates uncontrolled cell growth. Moreover, these pathogens can increase the likelihood of oncogenic transformation, leading to cancer development. Despite significant advancements in medicine, oncological research continues to seek innovative treatment techniques in light of the constraints imposed by traditional therapeutic agents. Virus-based therapy is a novel treatment method that has garnered significant interest due to its broad range of applications. Virotherapy employs oncolytic viruses that are genetically modified to target tumor cells specifically, undergo replication inside them and destroy the malignant cells. Additionally, this therapeutic approach elicits an anticancer response by boosting the patient's immune system. In addition, viruses are commonly employed as targeted delivery vectors for the precise transportation of various genes, medicinal compounds and immune-stimulating substances. Furthermore, virotherapy offers more excellent anticancer activity in combination with established treatment modalities such as immune therapy, chemotherapy and radiation therapy. This review presents a concise overview of the roles played by infectious agents, such as viruses in cancer progression. In addition, we have thoroughly summarized the advancements in utilizing viruses for their oncolytic properties in conjunction with established cancer treatment modalities such as chemotherapy, radiation and immunotherapy.

Exploring the Potential of Metformin in Mitigating Radiation-induced Gastrointestinal and Hematopoietic System Injury in Rats After Whole-body X-ray Radiation: An Experimental Study

BACKGROUND

The modern world faces a growing concern about the possibility of accidental radiation events. The Hematopoietic system is particularly vulnerable to radiationinduced apoptosis, which can lead to death. Metformin, a drug used to treat diabetes, has been shown to protect normal cells and tissues from the toxic effects of radiation. This study aimed to evaluate the effectiveness of metformin in mitigating radiation injury to the gastrointestinal and hematological systems of rats.

MATERIALS AND METHODS

The study involved 73 male rats. After total body irradiation with 7.5 Gy of X-rays, rats were treated with metformin. Seven days later, the rats were sacrificed and blood samples were taken for evaluation.

RESULTS

The study found that metformin was not effective in mitigating radiation injury. The histopathological assessment showed no significant changes in goblet cell injury, villi shortening, inflammation, or mucous layer thickness. In terms of biochemical evaluation, metformin did not significantly affect oxidative stress markers, but irradiation increased the mean MDA level in the radiation group. The complete blood count revealed a significant decrease in WBC and platelet, counts in the radiation group compared to the control group, but no significant difference was found between the radiation and radiation + metformin groups.

CONCLUSION

In conclusion, metformin may not be a good option for reducing radiation toxicity after accidental exposure. Despite treatment, there was no improvement in platelet, white blood cell, and lymphocyte counts, nor was there any decrease in oxidative stress. Further research is needed to explore other potential treatments for radiation injury.

A brain MRI dataset and baseline evaluations for tumor recurrence prediction after Gamma Knife radiotherapy

Prediction and identification of tumor recurrence are critical for brain cancer treatment design and planning. Stereotactic radiation therapy delivered with Gamma Knife has been developed as one of the common treatment approaches combined with others by delivering radiation that targets accurately on the tumor while not affecting nearby healthy tissues. In this paper, we release a fully publicly available brain cancer MRI dataset and the companion Gamma Knife treatment planning and follow-up data for the purpose of tumor recurrence prediction. The dataset contains original patient MRI images, radiation therapy data, and clinical information. Lesion annotations are provided, and inclusive preprocessing steps have been specified to simplify the usage of this dataset. A baseline framework based on a convolutional neural network is proposed companionably with basic evaluations. The release of this dataset will contribute to the future development of automated brain tumor recurrence prediction algorithms and promote the clinical implementations associated with the computer vision field. The dataset is made publicly available on The Cancer Imaging Archive (TCIA) ( https://doi.org/10.7937/xb6d-py67 ).

Application of nano-radiosensitizers in combination cancer therapy

Radiosensitizers are compounds or nanostructures, which can improve the efficiency of ionizing radiation to kill cells. Radiosensitization increases the susceptibility of cancer cells to radiation-induced killing, while simultaneously reducing the potentially damaging effect on the cellular structure and function of the surrounding healthy tissues. Therefore, radiosensitizers are therapeutic agents used to boost the effectiveness of radiation treatment. The complexity and heterogeneity of cancer, and the multifactorial nature of its pathophysiology has led to many approaches to treatment. The effectiveness of each approach has been proven to some extent, but no definitive treatment to eradicate cancer has been discovered. The current review discusses a broad range of nano-radiosensitizers, summarizing possible combinations of radiosensitizing NPs with several other types of cancer therapy options, focusing on the benefits and drawbacks, challenges, and future prospects.

Applications of tissue-specific and cancer-selective gene promoters for cancer diagnosis and therapy

Current treatment of solid tumors with standard of care chemotherapies, radiation therapy and/or immunotherapies are often limited by severe adverse toxic effects, resulting in a narrow therapeutic index. Cancer gene therapy represents a targeted approach that in principle could significantly reduce undesirable side effects in normal tissues while significantly inhibiting tumor growth and progression. To be effective, this strategy requires a clear understanding of the molecular biology of cancer development and evolution and developing biological vectors that can serve as vehicles to target cancer cells. The advent and fine tuning of omics technologies that permit the collective and spatial recognition of genes (genomics), mRNAs (transcriptomics), proteins (proteomics), metabolites (metabolomics), epiomics (epigenomics, epitranscriptomics, and epiproteomics), and their interactomics in defined complex biological samples provide a roadmap for identifying crucial targets of relevance to the cancer paradigm. Combining these strategies with identified genetic elements that control target gene expression uncovers significant opportunities for developing guided gene-based therapeutics for cancer. The purpose of this review is to overview the current state and potential limitations in developing gene promoter-directed targeted expression of key genes and highlights their potential applications in cancer gene therapy.

PBRM1 presents a potential prognostic marker and therapeutic target in duodenal papillary carcinoma

BACKGROUND

Due to its rarity, duodenal papillary carcinoma (DPC) is seldom studied as a unique disease and no specific molecular features or treatment guidelines are provided.

METHODS

Whole-exome sequencing was performed to gain new insights into the DPC mutation landscape and to identify potential signalling pathways and therapeutic targets. Mechanistically, immunohistochemistry (IHC), immunofluorescence, RNA-seq, ATAC-seq and in vitro cell function experiments were performed to confirm the underlying mechanisms.

RESULTS

We described the mutational landscape of DPC for the first time as a group of rare tumours with a high frequency of dysregulation in the chromatin remodelling pathway, particularly PBRM1-inactivating mutations that are significantly higher than duodenal adenocarcinomas and ampullary adenocarcinoma (27% vs. 0% vs. 7%, p < .01). In vitro cell experiments showed that downregulation of PBRM1 expression could significantly promote the cancer progression and epithelial-to-mesenchymal transition via the PBRM1-c-JUN-VIM axis. The IHC data indicated that PBRM1 deficiency (p = .047) and c-JUN expression (p < .001) were significantly associated with poor prognosis. Meanwhile, the downregulation of PBRM1 expression in HUTU-80 cells was sensitive to radiation, which may be due to the suppression of c-JUN by irradiation.

CONCLUSIONS

Our findings define a novel molecular subgroup of PBRM1-inactivating mutations in DPC. PBRM1 play an important role in DPC progression and may serve as a potential therapeutic target and prognostic indicator.

Microbial cytosine deaminase is a programmable anticancer prodrug mediating enzyme: antibody, and gene directed enzyme prodrug therapy

Cytosine deaminase (CDA) is a non-mammalian enzyme with powerful activity in mediating the prodrug 5-fluorcytosine (5-FC) into toxic drug 5-fluorouracil (5-FU), as an alternative directed approach for the traditional chemotherapies and radiotherapies of cancer. This enzyme has been frequently reported and characterized from various microorganisms. The therapeutic strategy of 5-FC-CDA involves the administration of CDA followed by the prodrug 5-FC injection to generate cytotoxic 5-FU. The antiproliferative activity of CDA-5-FC elaborates from the higher activity of uracil pathway in tumor cells than normal ones. The main challenge of the therapeutic drug 5-FU are the short half-life, lack of selectivity and emergence of the drug resistance, consistently to the other chemotherapies. So, mediating the 5-FU to the tumor cells by CDA is one of the most feasible approaches to direct the drug to the tumor cells, reducing its toxic effects and improving their pharmacokinetic properties. Nevertheless, the catalytic efficiency, stability, antigenicity and targetability of CDA-5-FC, are the major challenges that limit the clinical application of this approach. Thus, exploring the biochemical properties of CDA from various microorganisms, as well as the approaches for localizing the system of CDA-5-FC to the tumor cells via the antibody directed enzyme prodrug therapy (ADEPT) and gene directed prodrug therapy (GDEPT) were the objectives of this review. Finally, the perspectives for increasing the therapeutic efficacy, and targetability of the CDA-5-FC system were described.

Factors and molecular mechanisms of radiation resistance in cancer cells

PURPOSE

The aim of this work is to review the published studies on radiation resistance mechanisms and molecular markers involved in different tumors. The revision has been focused in the last 5 years (2016-2021).

CONCLUSIONS

Radioresistance is a cause of concern as it causes failure of radiation therapy and subsequent tumor relapse. Combination chemotherapy and radiation therapy are clinically successful in treating many types of tumors. Despite continued improvements in cancer treatment, locoregional recurrence or metastatic spread continues to occur in a high proportion of patients after being treated with radiation therapy or combination treatments. There is strong evidence that cancer stem cells contribute to radiation resistance, contributing to treatment failure. The mechanisms of radiation resistance in different tumors are not fully understood. A better understanding of cancer stem cells and the associated signaling pathways that regulate radiation resistance will open up new strategies for treating cancer by radiation therapy. Radiation can damage malignant cells mainly by the induction of DNA double strand breaks. However, in some tumors appear resistant cells that repopulate the tumor following therapy leading over time to the failure of the treatment. Native mechanisms and induced pathways, are the cause of radiation resistance. It has been described that numerous molecular markers acting through numerous mechanisms of action involved in radiation resistance, such as apoptosis resistance, alterations of cell growth, proliferation and DNA repair, hypoxia, increase in invasiveness and migration capacity, cell cycle alterations and expression of heat shock proteins, among others. Therefore, resistance to radiation is a multifactorial phenomenon that, in different cell types, it occurs through different regulatory mechanisms in which different molecules intervene. Resistance can be acquired by altering different regulatory pathways in different tumors. The knowledge of radiation resistance markers could help in the classification and treatment of patients with more aggressive tumors.

Design, synthesis and anticancer evaluation of 6,7-disubstituted-4-phenoxyquinoline derivatives bearing 1,8-naphthyridine-3-carboxamide moiety as novel multi-target TKIs

Giving the fact that the disorders of multiple receptor tyrosine kinases (RTKs) are characteristics of various cancers, we assumed that developing novel multi-target drugs might have an advantage in treating the complex cancers. Taking the multi-target c-Met inhibitor Foretinib as the leading compound, we discovered a novel series of 6,7-disubstituted-4-phenoxyquinoline derivatives bearing 1,8-naphthyridine-3-carboxamide moiety with the help of molecular docking. Among them, the most promising compound 33 showed a prominent activity against Hela (IC₅₀ = 0.21 µM), A549 (IC₅₀ = 0.39 µM), and MCF-7 (IC₅₀ = 0.33 µM), which were 3.28-4.82 times more active than that of Foretinib. Additionally, compound 33 dose dependently induced apoptosis by arresting A549 cells at G1 phase. Enzymatic assays and docking analyses were further confirmed that compound 33 was a multi-target inhibitor with the strong potencies against c-Met (IC₅₀ = 11.77 nM), MEK1 (IC₅₀ = 10.71 nM), and Flt-3 (IC₅₀ = 22.36 nM). In the A549 cells mediated xenograft mouse model, compound 33 inhibited the tumor growth (TGI = 64%) without obvious toxicity, establishing compound 33 as a promising candidate for cancer therapy.

Exploiting the efficacy of Tyro3 and folate receptors to enhance the delivery of gold nanoparticles into colorectal cancer cells in vitro

Colorectal cancer (CRC) is the fourth most common cancer in the world. Due to its asymptomatic nature, CRC is diagnosed at an advanced stage where the survival rate is <5%. Besides, CRC treatment using chemotherapy, radiotherapy and surgery often causes undesirable side-effects. As such, gold nanoparticles (GNPs) are envisaged in the field for the diagnosis and treatment of CRC. GNPs have unique physical, chemical and electrical properties at the nanoscale which make them suitable for application in biomedicine. However, for GNPs to become clinically effective, their internalisation efficiency in cancer cells must be enhanced. Folate receptor-α (FR) is overexpressed in CRC cells wherein FR helps in the uptake of folic acid within the cells. Tyro3, a novel tyrosine kinase receptor, drives cell proliferation and its overexpression is correlated with poor prognosis in CRC. Their upregulated expression in CRC cells relative to normal cells makes them an ideal target for GNPs using active targeting. Therefore, in this study receptors FR and Tyro3 were simultaneously targeted using specific antibody-coated GNPs in order to enhance the uptake and internalisation of GNPs in CRC cells in vitro. Four different types of coated-GNPs were synthesised GNPs-PEG, GNPs-anti-FR, GNPs-anti-Tyro3 and GNPs-anti-(FR + Tyro3) and incubated (0-50 ng) with three CRC cell lines namely CRL1790, CRL2159 and HCT116. Simultaneous targeting of these receptors by GNPs-anti-(FR + Tyro3) was found to be the most effective in internalisation in CRC cells compared with GNPs targeted singly to FR or Tyro3 (p <0.05). Besides this, results show that Tyro3 mediated similar internalisation efficacy to FR (p <0.05) in CRC cells using ICP-OES.

Step-by-Step Immune Activation for Suicide Gene Therapy Reinforcement

Gene-directed enzyme prodrug gene therapy (GDEPT) theoretically represents a useful method to carry out chemotherapy for cancer with minimal side effects through the formation of a chemotherapeutic agent inside cancer cells. However, despite great efforts, promising preliminary results, and a long period of time (over 25 years) since the first mention of this method, GDEPT has not yet reached the clinic. There is a growing consensus that optimal cancer therapies should generate robust tumor-specific immune responses. The advent of checkpoint immunotherapy has yielded new highly promising avenues of study in cancer therapy. For such therapy, it seems reasonable to use combinations of different immunomodulators alongside traditional methods, such as chemotherapy and radiotherapy, as well as GDEPT. In this review, we focused on non-viral gene immunotherapy systems combining the intratumoral production of toxins diffused by GDEPT and immunomodulatory molecules. Special attention was paid to the applications and mechanisms of action of the granulocyte-macrophage colony-stimulating factor (GM–CSF), a cytokine that is widely used but shows contradictory effects. Another method to enhance the formation of stable immune responses in a tumor, the use of danger signals, is also discussed. The process of dying from GDEPT cancer cells initiates danger signaling by releasing damage-associated molecular patterns (DAMPs) that exert immature dendritic cells by increasing antigen uptake, maturation, and antigen presentation to cytotoxic T-lymphocytes. We hypothesized that the combined action of this danger signal and GM–CSF issued from the same dying cancer cell within a limited space would focus on a limited pool of immature dendritic cells, thus acting synergistically and enhancing their maturation and cytotoxic T-lymphocyte attraction potential. We also discuss the problem of enhancing the cancer specificity of the combined GDEPT–GM–CSF–danger signal system by means of artificial cancer specific promoters or a modified delivery system.

An overview on breast cancer genetics and recent innovations: Literature survey

Breast cancer is one of the leading cancers nowadays. The genetical mechanism behind breast cancer development is an intricate one. In this review, the genetical background of breast cancer, particularly BRCA 1 and BRCA 2 had been included. Moreover, to summarize the genetics of breast cancer, the recent and ongoing preclinical and clinical studies on the treatment of BRCA-associated breast cancer had also been included. A prime knowledge is that the BRCA gene is the basis of breast cancer risk. How it mediates cell proliferation and associated mechanisms are reviewed here. BRCA 1 gene can influence all phases of the cell cycle and regulate cell cycle progression. BRCA 1 gene can also respond to DNA damages and induce responsive mechanisms. The action of the BRCA gene on associated protein has a wide consideration in breast cancer development. Heterogeneity in breast cancer makes them a fascinating and challenging stream to diagnose and treat. Several clinical therapies are available for breast cancer treatments. Chemotherapy, endocrine therapy, radiation therapy and immunotherapy are the milestones in the cancer treatments. Ral binding protein 1 is a promising target for breast cancer treatment and the platinum-based chemotherapies are the other remarkable fields. In immunotherapy, the usage of anti-programmed death (PD)-1 antibody is a new class of cancer immunotherapy that hinders immune effecter inhibition and potentially expanding preexisting anticancer immune responses. Breast cancer genetics and treatment strategies are crucial in escalating survival rates.

Non-viral Suicide Gene Therapy: Cytosine Deaminase Gene Directed by VEGF Promoter and 5-fluorocytosine as a Gene Directed Enzyme/prodrug System in Breast Cancer Model

The present study investigated the potential of vascular endothelial growth factor (VEGF) promoter to derive cytosine deaminase (CD) transfected by polyamidoamine (G4-PAMAM) dendrimers to 4T1 murine breast cancer cell line as gene-directed enzyme/prodrug therapy. The VEGF promoter and cytosine deaminase gene were cloned into the pEGFP-N1vector from the genomic DNA of 4T1 and E. coli, respectively. The frequency of transfection for VEGF-CD-pEGFP-N1 and pEGFP-N1- CD treated groups was 35±3 and 36±4, respectively. MTT assay was perform to evaluate the cytotoxic effects of converted 5-flurocytosine on 4T1 cells. Also, the optimal concentration of 5-FC in 4T1 cells transfected by VEGF-CD-pEGFP-N1 plasmid was evaluated. The GFP expression of transfected 4T1 cells by VEGF-CD-pEGFP-N1were observed by fluorescent microscopy and flowcytometry. Results demonstrated that the suicide CD gene was successfully expressed in 4T1 cells determined by RT-PCR and GFP expression. A concentration of 200 μg/ml 5-FC was identified as optimal dose of prodrug. Furthermore, the CD/5-FC enzyme/prodrug system not only demonstrated toxicity on transformed 4T1 cells but also exerted a 'bystander effect' determined by MTT assay. The results showed that by 35% transfection with VEGF-CD-pEGFP-N1and CD-pEGFP-N1 plasmids, 80% and 90% inhibition of the cells growth occurred, respectively.

Identification and Functional Validation of Radioresistance-Related Genes AHNAK2 and EVPL in Esophageal Squamous Cell Carcinoma by Exome and Transcriptome Sequencing Analyses

Introduction

Esophageal squamous cell carcinoma (ESCC) is often resistant to radiotherapy, likely due to sub-clones that survive and repopulate in the tumor. The analysis of genomic sequencing data related to radiotherapy will provide a better understanding of the intratumoral heterogeneity and genetic evolution of ESCC during radiotherapy.

Methods

We analyzed whole-exome sequencing data from pre- and post-irradiation ESCC patients at single-cell and bulk levels in public datasets. We investigated the gene functions involving radioresistance in ESCC cell lines. Furthermore, we established gene knockdown cell lines and explored the transcriptional alterations induced by RNA interference (RNAi) of these genes in KYSE-150 ESCC cell line.

Results

We identified three candidate genes related to radioresistance: AHNAK2, EVPL and LAMA5. Knockdown of AHNAK2 and EVPL genes led to increased radioresistance in ESCC cell lines, but not LAMA5. The transcriptome analysis indicated that these genes may regulate the expression of interleukins, interleukin receptors and chemokines by inhibiting the NF-κB and TNF signaling pathways in radioresistant ESCC cells, thereby suppressing their immune response.

Conclusion

These data may provide new therapeutic strategies by targeting general ESCC radioresistance-related genes, which may eventually help the development of targeted therapies.

Design, synthesis and biological evaluation of 7H-pyrrolo[2,3-d]pyrimidine derivatives containing 1,8-naphthyridine-4-one fragment

In this study, a series of pyrrolo [2,3-d]pyrimidine derivatives containing 1,8-naphthyridine-4-one fragment were synthesized and their biological activity were tested. Most of the target compounds displayed moderate to excellent activity against one or more cancer cell lines and low activity against human normal cell LO2 in vitro. The most promising compound 51, of which the IC₅₀ values were 0.66 μM, 0.38 μM and 0.44 μM against cell lines A549, Hela and MCF-7, shown more remarkable activity and better apoptosis effect than the positive control Cabozantinib. The structure-activity relationships (SARs) indicated that double-EWGs (such as R₃ = 2-Cl-4-CF₃) on the terminal phenyl rings was a key factor in improving the biological activity. In addition, the further research on compound 51 mainly included c-Met kinase activity and selectivity, concentration dependence, and molecular docking.

Cisplatin's dual-effect on the circadian clock triggers proliferation and apoptosis

The circadian clock, which generates the internal daily rhythm largely mediated through release of melatonin, can be disrupted in various ways. Multiple factors result in a disruption of the circadian cycle in the clinical context, of interest are anti-cancer drugs such as cisplatin. Cisplatin modulates the circadian clock through two mechanisms: 1) the circadian clock control of DNA excision repair and 2) the effect of circadian clock disruption on apoptosis. Cisplatin can stimulate multiple classified molecules, including DNA repair factors, DNA damage recognition factors and transcription factors in drug resistance and cisplatin-induced signal transduction. These factors interact with each other and can be transformed by DNA damage. Hence, these molecular interactions are intimately involved in cell proliferation and damage-induced apoptosis. Cisplatin has a dual-effect on circadian genes: upregulation of CLOCK expression causes an increase in proliferation but upregulation of BMAL1 expression causes an increase in apoptosis. Therefore, the interference of circadian genes by cisplatin can have multiple, opposing effects on apoptosis and cell proliferation, which may have unintended pro-cancer effects. Melatonin and intracellular Ca²⁺ also have a dual-effect on cell proliferation and apoptosis and can disrupt circadian rhythms.

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Cisplatin has a dual-effect on components of the circadian clock, increasing or decreasing cell proliferation and apoptosis.

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DNA excision repair and apoptosis are controlled by circadian rhythms.

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When cisplatin is combined with other agents, the effects are enhanced.

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These findings provide clinicians with the prospect to create effective chrono-cisplatin regimens for patients.

Oxidative stress associated metabolic adaptations regulate radioresistance in human lung cancer cells

Differential inherent and acquired radioresistance of human lung cancer cells contribute to poor therapeutic outcome and tumor recurrence after radiotherapy. Inherent radioresistance of lung cancer cells is known to be associated with ROS^Low cancer stem cells (CSCs). However, mechanism of acquired radioresistance in lung cancer cells is poorly understood. Here, we exposed human lung cancer cells (A549) to a cumulative dose of 40Gy and allowed the radioresistant (RR) survivors to divide and form macroscopic colonies after each fraction of 5Gy dose. The RR subline exhibited enrichment of cytosolic ROS^High cells without specific increase in mitochondrial ROS levels. We found a concomitant increase in the expression of redox regulatory transcription factor Nrf2 and its dependent antioxidant genes in RR cells and cell cycle delay as compared to parental cells. The treatment of RR cells with Nrf2 inhibitor resulted in decreased clonogenic survival indicating their addiction to Nrf2 for metabolic adaptations under high levels of cytosolic ROS. A causal role of inherent ROS levels in conferring radioresistance was established by sorting ROS^High and ROS^Low populations from parental and RR cells. It was observed that ROS^High population from both parental and RR cells exhibited radioresistance as observed by clonogenic assay. Interestingly, ROS^High population of cells exhibited higher levels of cellular thiols in both parental and RR cells. Thus, our observations highlight presence of a novel subpopulation in lung cancer cells, which exhibits radioresistance by maintaining 'oxidative stress' and Nrf2 dependent metabolic adaptations. We also posit Nrf2 pathway as a druggable target for radiosensitization of RR A549 cells.

A review of ultrasound-mediated microbubbles technology for cancer therapy: a vehicle for chemotherapeutic drug delivery

Background:

The unique behaviour of microbubbles under ultrasound acoustic pressure makes them useful agents for drug and gene delivery. Several studies have demonstrated the potential application of microbubbles as a non-invasive, safe and effective technique for targeted delivery of drugs and genes. The drugs can be incorporated into the microbubbles in several different approaches and then carried to the site of interest where it can be released by destruction of the microbubbles using ultrasound to achieve the required therapeutic effect.

Methods:

The objective of this article is to report on a review of the recent advances of ultrasound-mediated microbubbles as a vehicle for delivering drugs and genes and its potential application for the treatment of cancer.

Conclusion:

Ultrasound-mediated microbubble technology has the potential to significantly improve chemotherapy drug delivery to treatment sites with minimal side effects. Moreover, the technology can induce temporary and reversible changes in the permeability of cells and vessels, thereby allowing for drug delivery in a spatially localised region which can improve the efficiency of drugs with poor bioavailability due to their poor absorption, rapid metabolism and rapid systemic elimination.

Increasing the colon cancer cells sensitivity toward radiation therapy via application of Oct4-Sox2 complex decoy oligodeoxynucleotides

Low sensitivity of cancer stem cells toward regular cancer therapy strategies is an important issue in the field of cancer remedy. The concept of cancer stem cell elimination has been a topic of interest in the field of molecular medicine for a long time. At the current study, it was aimed to elevate the sensitivity of cancer stem-like cells toward radiotherapy by treating with Oct4-Sox2 complex decoy oligodeoxynucleotides (ODNs). After treating HT29 and HT29-ShE cells with Oct4-Sox2 complex decoy ODNs, and analyzing the cellular uptake and localization of decoys, treated cells and control groups were subjected to irradiation by fractionated 6MV X-ray with a final dose of 2 Gy. Thereafter, the influence of radiotherapy on ODNs treated groups and control group was investigated on cell viability, cell cycle, apoptosis, colonosphere formation and scratch assay. Cellular uptake and localization assays demonstrated that decoy ODNs can efficiently be transfected to the cells and reside in subcellular compartment, where they pose their action on gene regulation. Post radiotherapy analysis indicated statistical significance in decoy ODNs treated cells by means of lower cell viability, cell cycle arrest in G2/M phase, increased cellular apoptosis, and reduced cell motility. Also, formed colonospheres were smaller in size and fewer in numbers. Considering the role of Oct4, and Sox2 transcription factors in signaling pathways of preserving stemness and inducing reverse EMT, application of decoy strategy could increase the sensitivity of cancer cells toward irradiation, which has a potential to eliminate the cancerous cells from tumors and support cancer treatment.

Improving the Efficacy of Tumor Radiosensitization Through Combined Molecular Targeting

Chemoradiation, either alone or in combination with surgery or induction chemotherapy, is the current standard of care for most locally advanced solid tumors. Though chemoradiation is usually performed at the maximum tolerated doses of both chemotherapy and radiation, current cure rates are not satisfactory for many tumor entities, since tumor heterogeneity and plasticity result in chemo- and radioresistance. Advances in the understanding of tumor biology, a rapidly growing number of molecular targeting agents and novel technologies enabling the in-depth characterization of individual tumors, have fuelled the hope of entering an era of precision oncology, where each tumor will be treated according to its individual characteristics and weaknesses. At present though, molecular targeting approaches in combination with radiotherapy or chemoradiation have not yet proven to be beneficial over standard chemoradiation treatment in the clinical setting. A promising approach to improve efficacy is the combined usage of two targeting agents in order to inhibit backup pathways or achieve a more complete pathway inhibition. Here we review preclinical attempts to utilize such dual targeting strategies for future tumor radiosensitization.

Combination of NDRG2 overexpression, X-ray radiation and docetaxel enhances apoptosis and inhibits invasiveness properties of LNCaP cells

OBJECTIVE

N-myc downstream regulated gene 2 (NDRG2) is identified as a promising candidate tumor suppressor in several human malignancies including prostate cancer (PCa). Here, we investigated the effect of combined NDRG2 overexpression, x-ray radiation (RTX), and docetaxel (DTX) against viability and invasiveness properties of LNCaP cells.

MATERIAL AND METHODS

A plasmid harboring NDRG2 gene under transcriptional control of prostate-specific enhancing sequence regulatory element was constructed to overexpress NDRG2 in PCa cell lines. The effects of NDRG2 overexpression in combination with RTX and DTX on viability, proliferation, and apoptosis of LNCaP cells were evaluated using MTT, colony formation, and annexin V flowcytometirc assays. Migration and invasion of NDRG2-overexpressed cells as well as expression of matrix metalloproteinses-2 (MMP2) and -9 (MMP9) were also assessed using transwell chamber assay and real-time PCR.

RESULTS

The results of fluorescence microscopy and real-time PCR showed a high and specific overexpression of NDRG2 in LNCaP cells. Overexpression of NDRG2 significantly reduced cell viability and increased apoptosis of LNCaP cell. Migration, invasion, as well as the expression of MMP2 and MMP9, was decreased following NDRG2 overexpression. Combination of NDRG2 overexpression with RTX and DTX decreased the viability, invasion, and migration of LNCaP cells synergistically.

CONCLUSION

These results indicate that a combination of NDRG2 overexpression with chemotherapy and radiotherapy can be considered for effective treatment of PCa.

A phase 1 trial of the safety, tolerability and biological effects of intravenous Enadenotucirev, a novel oncolytic virus, in combination with chemoradiotherapy in locally advanced rectal cancer (CEDAR)

BACKGROUND

Chemoradiotherapy remains the standard of care for locally advanced rectal cancer. Efforts to intensify treatment and increase response rates have yet to yield practice changing results due to increased toxicity and/or absence of increased radiosensitization. Enadenotucirev (EnAd) is a tumour selective, oncolytic adenovirus which can be given intravenously. Pre-clinical evidence of synergy with radiation warrants further clinical testing and assessment of safety with radiation.

METHODS

Eligibility include histology confirmed locally advanced rectal cancer that require chemoradiation. The trial will use a Time-to-Event Continual Reassessment Model-based (TiTE-CRM) approach using toxicity and efficacy as co-primary endpoints to recommend the optimal dose and treatment schedule 30 patients will be recruited. Secondary endpoints include pathological complete response the neoadjuvant rectal score. A translational program will be based on a mandatory biopsy during the second week of treatment for 'proof-of-concept' and exploration of mechanism. The trial opened to recruitment in July 2019, at an expected rate of 1 per month for up to 4 years.

DISCUSSION

Chemoradiation with Enadenotucirev as a radiosensitiser in locally Advanced Rectal cancer (CEDAR) is a prospective multicentre study testing a new paradigm in radiosensitization in rectal cancer. The unique ability of EnAd to selectively infect tumour cells following intravenous delivery is an exciting opportunity with a clear translational goal. The novel statistical design will make efficient use of both toxicity and efficacy data to inform subsequent studies.

TRIAL REGISTRATION

ClinicalTrial.gov, NCT03916510. Registered 16th April 2019.

Bioengineered smart bacterial carriers for combinational targeted therapy of solid tumours

Despite many endeavours for the development of new anticancer drugs, effective therapy of solid tumours remains a challenging issue. The current cancer chemotherapies may associate with two important limitations, including the lack/trivial specificity of treatment modalities towards diseased cells/tissues resulting in undesired side effects, and the emergence of drug-resistance mechanisms by tumour cells causing the failure of the treatment. Much attention, therefore, has currently been paid to develop smart and highly specific anticancer agents with maximal therapeutic impacts and minimal side effects. Among various strategies used to target cancer cells, bacteria-based cancer therapies (BCTs) have been validated as potential gene/drug delivery carriers, which can also be engineered to be used in diagnosis processes. They can be devised to selectively target the tumour microenvironment (TME), within which they may preferentially proliferate in the necrotic and anaerobic parts - often inaccessible to other therapeutics. BCTs are capable to sense and respond to the environmental signals, upon which they are considered as smart microrobots applicable in the controlled delivery of therapeutic agents to the TME. In this review, we aimed to provide comprehensive insights into the potentials of the bioengineered bacteria as smart and targeted bio-carriers and discuss their applications in cancer therapy.

Bromelain Inhibitory Effect on Colony Formation: An In vitro Study on Human AGS, PC3, and MCF7 Cancer Cells

Bromelain is dotted with anticancer properties on various cancer cell lines. Anticancer pathways of bromelain, as well related intervening signalization are under investigation. Investigating the inhibitory potential of bromelain on AGS, PC3, and MCF7 cells proliferation and colony formation. The bromelain inhibitory potential on AGS, PC3, and MCF7 cells proliferation at various bromelain concentrations was assessed by MTT; thereby, bromelain potency on colony formation impediment was evaluated using clonogenic assays at determined 50% inhibitory concentrations (IC₅₀) on four different cell densities (10, 50, 100, and 200 cells per well). Bromelain inhibits AGS, PC3, and MCF7 cells proliferation in such a dose-dependent manner. Determined IC₅₀ to AGS, PC3, and MCF7 cells were 65, 60 and 65μg/ml respectively. At IC₅₀, bromelain significantly suppressed the AGS, PC3, and MCF7 cells colony formation at four treated densities (10, 50, 100 and 200 cells per well). Plating efficiency percentage and cell surviving fraction were decreased after bromelain treatment to AGS, PC3, and MCF7 human cancer cells as a function of initial cell density. The 50, 50 or 100, and 10 or 50 cells per well were considered to be optimum number of initial cell density for AGS, PC3, and MCF7 cells. Cell proliferative and colony formation inhibition are two pathways to in vitro bromelain anticancer effects. The current study displayed a dose-dependent inhibitory effect of bromelain, as well impeding colony formation AGS, PC3, and MCF7 human cancer cells.

Nanomedicines for cancer therapy: current status, challenges and future prospects

The emergence of nanomedicine as an innovative and promising alternative technology shows many advantages over conventional cancer therapies and provides new opportunities for early detection, improved treatment, and diagnosis of cancer. Despite the cancer nanomedicines’ capability of delivering chemotherapeutic agents while providing lower systemic toxicity, it is paramount to consider the cancer complexity and dynamics for bridging the translational bench-to-bedside gap. It is important to conduct appropriate investigations for exploiting the tumor microenvironment, and achieving a more comprehensive understanding of the fundamental biological processes in cancer and their roles in modulating nanoparticle–protein interactions, blood circulation, and tumor penetration. This review provides an overview of the current cancer nanomedicines, the major challenges, and the future opportunities in this research area.

Cucurbitacin I induces cancer cell death through the endoplasmic reticulum stress pathway

Endoplasmic reticulum stress (ERS) is usually involved in tumor development and progression, and anticancer agents have recently been recognized to induce ERS. Cucurbitacin-I showed a potent anticancer action by inducing apoptosis through the inhibition of signal transducer and activator of transcription 3 pathway and triggering autophagic cell death. It is not known whether ERS mediates the cancer cell death induced by cucurbitacin-I. Here, we investigated the role of ERS in cucurbitacin-I-treated SKOV3 ovarian cancer cells and PANC-1 pancreatic cancer cells. We confirmed that cucurbitacin-I caused cell death and stirred excessive ERS levels by activating inositol requiring enzyme 1α (IRE1α) and protein kinase R-like endoplasmic reticulum kinase (PERK), as well as PERK downstream factors, including IRE1α and C/EBP homologous protein, but not activating transcription factor 6 (ATF6α) pathway, which was in parallel with the increased Bax and caspase-12-dependent ERS-associated apoptosis, autophagy and autophagy flux levels and caspase-independent nonapoptotic cell death. Furthermore, 4-phenylbutyrate, an ERS inhibitor, suppressed cucurbitacin-I-induced apoptosis, autophagy, autophagy flux, and autophagic cell death. Simultaneously, there are positive correlations among ERS and cucurbitacin-I-induced reactive oxygen species and Ca ²⁺ . Our results suggested that cucurbitacin-I-induced cancer cell death through the excessive ERS and CHOP-Bax and caspase-12-dependent ERS-associated apoptosis, as well as ERS-dependent autophagy, autophagy flux, and caspase-independent nonapoptotic cell death. These novel signaling insights may be useful for developing new, effective anticancer strategies in oncotherapy.

Cell penetrating peptides in preclinical and clinical cancer diagnosis and therapy

Delivery of imaging reagents and drugs to tumors is essential for cancer diagnosis and therapy. In addition to therapeutic and diagnostic functionalities, peptides have potential benefits such as biocompatibility, ease to synthesize, smaller size, by-passing off-target side effects, and achieving the beneficial effects with lower-administered dosages. A particular type of peptide known as cell penetrating peptides (CPP) have been predominantly studied during last twenty years as they are not only capable to translocate themselves across membranes but also allow carrier drugs to translocate across plasma membrane, by different mechanisms depending on the CPP. This is of great potential importance in drug delivery systems, as the ability to pass across membranes is crucial to many drug delivery systems. In spite of significant progress in design and application of CPP, more investigations are required to further improve their delivery to tumors, with reduced side-effect and enhanced therapeutic efficacy. In this review, we emphasis on current advancements in preclinical and clinical trials based on using CPP for more efficient delivery of anti-cancer drugs and imaging reagents to cancer tissues and individual cells associated with them. We discuss the evolution of the CPPs-based strategies for targeted delivery, their current status and strengths, along with summarizing the role of CPPs in targeted drug delivery. We also discuss some recently reported diagnostic applications of engineered protease-responsive substrates and activable imaging complexes. We highlight the recent clinical trial data by providing a road map for better design of the CPPs for future preclinical and clinical applications.

Apoptotic role of marine sponge symbiont Bacillus subtilis NMK17 through the activation of caspase-3 in human breast cancer cell line

The aim of the present study was to evaluate the diverse potential biological activity of partially purified crude extract (PPCEBS) of marine Bacillus subtilis NMK17 associated with marine sponge Clathria frondifera. Symbionts were isolated from a marine sponge, only the potential strain which exhibited apoptosis was sequenced using 16S rRNA and extract of the active strain was subjected to purification using HPLC. The potential pro-apoptotic role of PPCEBS was investigated in MCF-7 human breast cancer cell line for cytotoxicity by MTT assay, which showed dose-dependent cytotoxicity on 24 h of exposure. The apoptotic findings demonstrated that PPCEBS significantly induces apoptosis, which was characterised by apoptotic morphological changes. Further, an increased expression of the Caspase 3 and Bax whereas decreased Bcl-2 was confirmed by immunofluorescence and western blotting analysis in MCF-7 cell line, which revealed that PPCEBS has potent apoptosis-inducing property. Added to the desirable apoptotic activity, PPCEBS exhibited excellent antibacterial and antioxidant activities too. The pharmacological effect of the marine sponge-associated bacteria from Gulf of Mannar India needs further attention in discovering new bioactive compounds. Our results suggested that the compounds present in the PPCEBS in marine bacterial B. subtilis NMK17 could be candidates for developing an apoptosis-specific drug with minimal toxicity. This study indicated that marine sponge-associated bacteria could be a good source to find the cytotoxic metabolites which would induce apoptosis and cause cancer cell death. Also, this study explores that marine natural products as a potential source of pharmaceuticals.

Radiation therapy affects the mechanical behavior of human umbilical vein endothelial cells

Radiation therapy has been widely utilized as an effective method to eliminate malignant tumors and cancerous cells. However, subjection of healthy tissues and the related networks of blood vessels adjacent to the tumor area to irradiation is inevitable. The aim of this study was to investigate the consequent effects of fractionation radiotherapy on the mechanical characteristics of human umbilical vein endothelial cells (HUVECs) through alterations in cytoskeleton organization and cell and nucleus morphology. In order to simulate the clinical condition of radiotherapy, the HUVECs were exposed to the specific dose of 2 Gy for 1-4 times among four groups with incremental total dose from 2 Gy up to 8 Gy. Fluorescence staining was performed to label F-actin filaments and nuclei. Micropipette aspiration and standard linear solid model were employed to evaluate the elastic and viscoelastic characteristics of the HUVECs. Radiotherapy significantly increased cell elastic moduli. Due to irradiation, instantaneous and equilibrium Young's modulus were also increased. Radiotherapy diminished HUVECs viscoelastic behavior and shifted their creep compliance curves downward. Furthermore, gamma irradiation elevated the nuclei sizes and to a lesser extent the cells sizes resulting in the accumulation of F-actin filaments within the rest of cell body. Endothelial stiffening correlates with endothelial dysfunction, hence the results may be helpful when the consequent effects of radiotherapy are the focus of concern.

Engineering functional inorganic-organic hybrid systems: advances in siRNA therapeutics

Cancer treatment still faces a lot of obstacles such as tumor heterogeneity, drug resistance and systemic toxicities. Beyond the traditional treatment modalities, exploitation of RNA interference (RNAi) as an emerging approach has immense potential for the treatment of various gene-caused diseases including cancer. The last decade has witnessed enormous research and achievements focused on RNAi biotechnology. However, delivery of small interference RNA (siRNA) remains a key challenge in the development of clinical RNAi therapeutics. Indeed, functional nanomaterials play an important role in siRNA delivery, which could overcome a wide range of sequential physiological and biological obstacles. Nanomaterial-formulated siRNA systems have potential applications in protection of siRNA from degradation, improving the accumulation in the target tissues, enhancing the siRNA therapy and reducing the side effects. In this review, we explore and summarize the role of functional inorganic-organic hybrid systems involved in the siRNA therapeutic advancements. Additionally, we gather the surface engineering strategies of hybrid systems to optimize for siRNA delivery. Major progress in the field of inorganic-organic hybrid platforms including metallic/non-metallic cores modified with organic shells or further fabrication as the vectors for siRNA delivery is discussed to give credit to the interdisciplinary cooperation between chemistry, pharmacy, biology and medicine.

Tip60 is associated with resistance to X-ray irradiation in prostate cancer

Tip60, an oncogene, accelerates cell growth by regulating androgen receptor translocation into the nucleus in prostate cancer. However, the mechanism of Tip60 in the response of prostate cancer to radiotherapy, and radioresistance, has not been studied. Using human prostate cancer samples and two human prostate cancer cell lines (LNCaP and DU145), Tip60 protein expression and the acetylation of ataxia telangiectasia mutant (ATM) were analysed by western blotting and immunoprecipitation. Tip60 was downregulated with small interfering RNA. Cells were irradiated using X‐rays at 0.25 Gy·min⁻¹. Cell viability was assessed by the MTT assay. The expression of Tip60 protein was increased in radioresistant prostate cancer tissues in comparison with radiosensitive tissues, which was also confirmed in both irradiated DU145 and LNCaP cells. Furthermore, the acetylation of ATM was also upregulated in a time‐dependent manner after irradiation of both DU145 and LNCaP cells. Additionally, depletion of Tip60 decreased the survival of LNCaP and DU145 cells by inducing apoptosis, reduced the acetylation of ATM and decreased the expression of phosphorylated ATM, Chk2 and cdc25A in both DU145 and LNCaP cells after X‐ray irradiation. The results of this study demonstrated that the expression of Tip60 may be related to the radioresistance of prostate cancer and could serve as a promising predictive factor for prostate cancer patients receiving radiotherapy.

Radiation-Induced Changes of microRNA Expression Profiles in Radiosensitive and Radioresistant Leukemia Cell Lines with Different Levels of Chromosome Abnormalities

In our study, we estimate an effect from chromosome aberrations and genome mutations on changes in microRNA expression profiles in cancer cell lines demonstrating different radiosensitivity. Here, cell viability and microRNA spectrum have been estimated 1, 4, and 24 h after irradiation. MiSeq high-throughput sequencing system (Illumina, San Diego, CA, USA) is employed to perform microRNA spectrum estimation. In the K562 cell line, the number of expressed microRNAs in chromosomes demonstrates a more pronounced variation. An analysis of microRNA effects on signaling pathway activity demonstrates differences in post-transcriptional regulation of the expression of genes included into 40 signaling pathways. In the K562 cell line, microRNA dynamics analyzed for their dependence on chromosome localization show a wider scattering of microRNA expression values for a pair of chromosomes compared to the HL-60 cell line. An analysis of microRNAs expression in the K562 and HL-60 cell lines after irradiation has shown that chromosome abnormalities can affect microRNA expression changes. A study of radiation-induced changes of microRNA expression profiles in the K562 and HL-60 cell lines has revealed a dependence of microRNA expression changes on the number of chromosome aberrations and genome mutations.

Synergistic Effects of NDRG2 Overexpression and Radiotherapy on Cell Death of Human Prostate LNCaP Cells

BACKGROUND

Radiation therapy is among the most conventional cancer therapeutic modalities with effective local tumor control. However, due to the development of radio-resistance, tumor recurrence and metastasis often occur following radiation therapy. In recent years, combination of radiotherapy and gene therapy has been suggested to overcome this problem. The aim of the current study was to explore the potential synergistic effects of N-Myc Downstream-Regulated Gene 2 (NDRG2) overexpression, a newly identified candidate tumor suppressor gene, with radiotherapy against proliferation of prostate LNCaP cell line.

MATERIALS AND METHODS

In this study, LNCaP cells were exposed to X-ray radiation in the presence or absence of NDRG2 overexpression using plasmid PSES- pAdenoVator-PSA-NDRG2-IRES-GFP. The effects of NDRG2 overexpression, X-ray radiation or combination of both on the cell proliferation and apoptosis of LNCaP cells were then analyzed using MTT assay and flow cytometery, respectively.

RESULTS

Results of MTT assay showed that NDRG2 overexpression and X-ray radiation had a synergistic effect against proliferation of LNCaP cells. Moreover, NDRG2 overexpression increased apoptotic effect of X-ray radiation in LNCaP cells synergistically.

CONCLUSION

Our findings suggested that NDRG2 overexpression in combination with radiotherapy may be an effective therapeutic option against prostate cancer.

Accelerated senescence in skin in a murine model of radiation-induced multi-organ injury

Accidental high-dose radiation exposures can lead to multi-organ injuries, including radiation dermatitis. The types of cellular damage leading to radiation dermatitis are not completely understood. To identify the cellular mechanisms that underlie radiation-induced skin injury in vivo, we evaluated the time-course of cellular effects of radiation (14, 16 or 17 Gy X-rays; 0.5 Gy/min) in the skin of C57BL/6 mice. Irradiation of 14 Gy induced mild inflammation, observed histologically, but no visible hair loss or erythema. However, 16 or 17 Gy radiation induced dry desquamation, erythema and mild ulceration, detectable within 14 days post-irradiation. Histological evaluation revealed inflammation with mast cell infiltration within 14 days. Fibrosis occurred 80 days following 17 Gy irradiation, with collagen deposition, admixed with neutrophilic dermatitis, and necrotic debris. We found that in cultures of normal human keratinocytes, exposure to 17.9 Gy irradiation caused the upregulation of p21/waf1, a marker of senescence. Using western blot analysis of 17.9 Gy-irradiated mice skin samples, we also detected a marker of accelerated senescence (p21/waf1) 7 days post-irradiation, and a marker of cellular apoptosis (activated caspase-3) at 30 days, both preceding histological evidence of inflammatory infiltrates. Immunohistochemistry revealed reduced epithelial stem cells from hair follicles 14-30 days post-irradiation. Furthermore, p21/waf1 expression was increased in the region of the hair follicle stem cells at 14 days post 17 Gy irradiation. These data indicate that radiation induces accelerated cellular senescence in the region of the stem cell population of the skin.

Novel carbohydrate-substituted metallo-porphyrazine comparison for cancer tissue-type specificity during PDT

A longstanding obstacle to cancer eradication centers on the heterogeneous nature of the tissue that manifests it. Variations between cancer cell resistance profiles often result in a survival percentage following classic therapeutics. As an alternative, photodynamic therapys' (PDT) unique non-specific cell damage mechanism and high degree of application control enables it to potentially deliver an efficient treatment regime to a broad range of heterogeneous tissue types thereby overcoming individual resistance profiles. This study follows on from previous design, characterization and solubility analyses of three novel carbohydrate-ligated zinc-porphyrazine (Zn(II)Pz) derivatives. Here we report on their PDT application potential in the treatment of five common cancer tissue types in vitro. Following analyses of metabolic homeostasis, toxicity and cell death induction, overall Zn(II)Pz-PDT proved comparably efficient between all cancer tissue populations. Differential localization patterns of Zn(II)Pz derivatives between cell types did not appear to influence the overall PDT effect. All cell types exhibited significant disruptions to mitochondrial activity and associated ATP production levels. Toxicity and chromatin structure profiles revealed indiscernible patterns of damage between Zn(II)Pz derivatives and cell type. The subtle differences observed between individual Zn(II)Pz derivatives is most likely due to a combination of carbohydrate moiety characteristics on energy transfer processes and associated dosage optimization requirements per tissue type. Collectively, this indicates that resistance profiles are negated to a significant extent by Zn(II)Pz-PDT making these derivatives attractive candidates for PDT applications across multiple tissue types and subtypes.

MiR-20a-5p promotes radio-resistance by targeting Rab27B in nasopharyngeal cancer cells

BACKGROUND

MicroRNAs (miRNAs) was reported to be involved in cancer radio-resistance, which remains a major obstacle for effective cancer therapy.

METHODS

The differently expressed miRNAs were detected by RNA-seq experiment in nasopharyngeal cancer (NPC) cells. MiR-20a-5p was selected as our target, which was subject to finding its target gene Rab27B via bioinformatics analysis. The qRT-PCR, western blot and the luciferase reporter assays were performed to confirm Rab27B as the target of miR-20a-5p. In addition, the roles of miR-20a-5p in NPC radio-resistance were detected by transfection of either miR-20a-5p-mimic or miR-20a-5p-antagomiR. The involvement of Rab27B with NPC radio-resistance was also detected by the experiments with siRNA-mediated repression of Rab27B or over-expression of GFP-Rab27B. Wound healing and invasion assays were performed to detect the roles of both miR-20a-5p and Rab27B.

RESULTS

MiR-20a-5p promotes NPC radio-resistance. We identified that its target gene Rab27B negatively correlates with miR-20a-5p-mediated NPC radio-resistance by systematic studies of a radio-sensitive (CNE-2) and resistant (CNE-1) NPC cell lines. Repression of Rab27B by siRNA suppresses cell apoptosis and passivates CNE-2 cells, whereas over-expression of Rab27B triggered cell apoptosis and sensitizes CNE-1 cells.

CONCLUSIONS

MiR-20a-5p and its target gene Rab27B might be involved in the NPC radio-resistance. Thus the key players and regulators involved in this pathway might be the potential targets for developing effective therapeutic strategies against NPC.

Retargeted adenoviruses for radiation-guided gene delivery

The combination of radiation with radiosensitizing gene delivery or oncolytic viruses promises to provide an advantage that could improve the therapeutic results for glioblastoma. X-rays can induce significant molecular changes in cancer cells. We isolated the GIRLRG peptide that binds to radiation-inducible 78 kDa glucose-regulated protein (GRP78), which is overexpressed on the plasma membranes of irradiated cancer cells and tumor-associated microvascular endothelial cells. The goal of our study was to improve tumor-specific adenovirus-mediated gene delivery by selectively targeting the adenovirus binding to this radiation-inducible protein. We employed an adenoviral fiber replacement approach to conduct a study of the targeting utility of GRP78-binding peptide. We have developed fiber-modified adenoviruses encoding the GRP78-binding peptide inserted into the fiber-fibritin. We have evaluated the reporter gene expression of fiber-modified adenoviruses in vitro using a panel of glioma cells and a human D54MG tumor xenograft model. The obtained results demonstrated that employment of the GRP78-binding peptide resulted in increased gene expression in irradiated tumors following infection with fiber-modified adenoviruses, compared with untreated tumor cells. These studies demonstrate the feasibility of adenoviral retargeting using the GRP78-binding peptide that selectively recognizes tumor cells responding to radiation treatment.

Functional Genomic Investigation of the Molecular Biological Impact of Electron Beam Radiation in Lymphoma Cells

PURPOSE

The biological response of electron beam radiation (EBR) in tumors remains underexplored. This study describes the molecular biological and genomic impact of EBR on tumor cells.

METHODS

A mouse model bearing Dalton's lymphoma ascites cells was exposed to an 8-MeV pulsed electron beam, at a dose rate of 2 Gy/min using a microtron, a linear accelerator. The radiation-induced changes were assessed by histopathology, fluorescence-activated cell sorting, signaling pathway-focused reporter assays, and gene expression by microarray analysis.

RESULTS

EBR was found to increase apoptosis and G2-M cell cycle arrest with concomitant tumor regression in vivo. The microarray data revealed that EBR induced tumor regression, apoptosis, and cell cycle arrest mediated by p53, PPAR, and SMAD2/3/4 signaling pathways. Activation of interferon regulatory factor and NFkB signaling were also found upon EBR. Chemo-genomics exploration revealed the possibility of drugs that can be effectively used in combination with EBR.

CONCLUSION

For the first time, an 8-MeV pulse EBR induced genomic changes, and their consequence in molecular and biological processes were identified in lymphoma cells. The comprehensive investigation of radiation-mediated responses in cancer cells also revealed the potential therapeutic features of EBR.

Progress and problems with the use of suicide genes for targeted cancer therapy

Among various gene therapy methods for cancer, suicide gene therapy attracts a special attention because it allows selective conversion of non-toxic compounds into cytotoxic drugs inside cancer cells. As a result, therapeutic index can be increased significantly by introducing high concentrations of cytotoxic molecules to the tumor environment while minimizing impact on normal tissues. Despite significant success at the preclinical level, no cancer suicide gene therapy protocol has delivered the desirable clinical significance yet. This review gives a critical look at the six main enzyme/prodrug systems that are used in suicide gene therapy of cancer and familiarizes readers with the state-of-the-art research and practices in this field. For each enzyme/prodrug system, the mechanisms of action, protein engineering strategies to enhance enzyme stability/affinity and chemical modification techniques to increase prodrug kinetics and potency are discussed. In each category, major clinical trials that have been performed in the past decade with each enzyme/prodrug system are discussed to highlight the progress to date. Finally, shortcomings are underlined and areas that need improvement in order to produce clinical significance are delineated.