BH3 Mimetic Peptides: An Effective Strategy to Complement Anticancer Therapy.

Apoptosis, a natural process of programmed cell death, is a promising therapeutic target as the disruption of apoptosis evolves in many diseases including cancer. Several pieces of evidence indicate that errors in apoptotic pathways result in the imbalance between cell proliferation and death, allowing cells with genetic abnormalities to survive. The intrinsic and extrinsic pathways of apoptosis utilize different caspases to execute the event of cell death through the cleavage of hundreds of proteins. Proteins from the Bcl-2 family, a pivotal component of the mitochondrial apoptosis pathway, activate the death signal either directly or indirectly involving mitochondrial translocation of Bax/Bak, which are recognized critical elements in defective apoptosis. The majority of chemotherapeutic drugs destroy cancer cells by activating the apoptotic machinery via Bcl-2/Bax-dependent process and failure of which leads to an intrinsic chemoresistance. Recent insights into the dynamic action of pro-survival Bcl-2 proteins in cancer pathogenesis and resistance has set the stage for the development of small molecules as Bcl-2 antagonist and modulators of apoptosis. The BH3-only proteins are vital inducers of the mitochondrial apoptosis mechanism that operate either by assuming the functional activity of the proapoptotic Bcl-2 family members or by impeding the antiapoptotic Bcl-2 proteins. Based on the structural interaction studies between the proapoptotic and anti-apoptotic proteins, several synthetic peptides have been designed to functionally mimic the BH3 domain, targeting directly the pro-survival Bcl-2 proteins. The "BH3-peptide mimetics" a novel class of Bcl-2 protein antagonists essentially play an important role in the treatment of malignancies as they are predicted to persuade non-receptor mediated programmed cell death. This review summarizes the most promising BH3-peptide mimetic compounds that function as selective antagonists of Bcl-2 proteins and would be effective in treating various cancers.

Combination of bendamustine-azacitidine against Syk target of breast cancer: an in silico study.

Breast cancer (BC) is the most serious and second leading cause of death in women worldwide. When breast cancer is diagnosed and treated early, the chance of long-term survival is up to 90%. On the other hand, 90% of BC patient deaths are due to metastasis and a lack of effective early diagnosis. The existing conventional chemotherapy provides negative feedback due to transportation barriers towards the action sites, multidrug resistance, poor bio-availability, non-specific delivery and systemic side effects on the healthy tissue. Syk protein Kinase has been reported in BC, as a tumor modulator, providing a pro-survival signal and also by restricting epithelial-mesenchymal transition, enhancing cell-cell interactions and inhibiting migration. In the present study, we explored the possibility of targeting BC by attenuating Syk protein Kinase. Hence, we have conjugated the hydrophobic Bendamustine (BEN) and hydrophilic Azacitidine (AZA) anticancer drugs to evaluate their efficacy against BC. The native drugs (BEN and AZA) and designed drug-drug conjugate (BEN-AZA) were docked with Syk protein. Then, the docked complex was performed for Binding Free Energy and Molecular Dynamics Simulations. Furthermore, DFT and ADME properties were carried out. The results revealed that the designed drug-drug conjugate has a better docking score, ΔGbind and admirable stability throughout the simulation when compared with native drugs. In DFT and ADME analyses, the designed drug-drug conjugate has shown good stereo electronic features and pharmaceutical relevant parameters than that of native drugs. The overall results suggested that the designed drug-drug conjugate may be a suitable candidate for BC treatment.Communicated by Ramaswamy H. Sarma.

HPV-mediated Cervical Cancer: A Systematic Review on Immunological Basis, Molecular Biology, and Immune Evasion Mechanisms.

BACKGROUND: Human papillomavirus (HPV), one of the most frequently transmitted viruses, causes several malignancies, including cervical cancer. AIM: Owing to its unique pathogenicity, the HPV virus can persist in the host organism for a longer duration than other viruses to complete its lifecycle. During its association with the host, HPV causes various pathological conditions affecting the immune system by evading the host's immune mechanisms, thereby leading to the progression of various diseases, including cancer. METHOD: To date, ~ 150 serotypes have been identified, and certain high-risk HPV types are known to be associated with genital warts and cervical cancer. As of now, two prophylactic vaccines are in use for the treatment of HPV infection; however, no effective antiviral drug is available for HPVassociated disease/infections. Numerous clinical and laboratory studies have been conducted to formulate an effective and specific vaccine against HPV infections and associated diseases. RESULT: As the immunological basis of HPV infection and associated disease progress persist indistinctly, deeper insights into immune evasion mechanism and molecular biology of disease would aid in developing an effective vaccine. CONCLUSION: Thus, this systematic review focuses on the immunological aspects of HPV-associated cervical cancer by uncovering immune evasion strategies adapted by HPV.

Integrative miRNA-mRNA functional analysis identifies miR-182 as a potential prognostic biomarker in breast cancer.

Breast cancer (BC) is a heterogeneous disease distinct from major clinical hindrances, and microRNAs (miRNAs) have been accounted to partake in BC progression. Identifying potential miRNAs and their pathological significance in BC could pave the way for precisely targeted treatments. This study exploits transcriptomic BC miRNA, mRNA cohorts, and prognostic significance via an integrative functional approach. miRNA transcriptomic cohorts (GSE45666, GSE40267, and GSE19783) were utilized to disseminate differentially expressed miRNAs (DEmiRNAs) and their expression in the clinicopathological variables of BC. miR-182 was identified as a potent candidate, differentially expressed between each BC stage and its adjacent normal samples. The expression of miR-182 was significantly associated with estrogen receptor (ER) (p = 0.052), and closely related to progesterone receptor (PR) (p = 0.061) and human epidermal growth factor receptor 2 (Her2) (p = 0.077). miRNA-mRNA regulatory targets were predicted using six different databases, namely, TargetScan, miRDB, Diana, miRNet, TargetMiner, and miRWalk. Twenty-four promising mRNA regulatory targets were potentially identified for miR-182 and thus highly enriched with cellular metabolic processes, proteoglycans, and focal adhesion pathways in the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) terms. Subsequently, the F-box and WD repeat domain containing 7, E3 ubiquitin protein ligase (FBXW7) gene was recognized as a hub with the highest connectivity score in the protein-protein interaction network. Furthermore, miR-182 and FBXW7 were associated with poor prognostic clinical outcomes in BC patients. Thus, our integrated functional analysis suggests that miR-182 might lead to a new therapeutic target in BC manifestation.

Systemic Multi-Omics Analysis Reveals Amplified P4HA1 Gene Associated With Prognostic and Hypoxic Regulation in Breast Cancer.

Breast cancer (BC) is a common malignant tumor in females around the world. While multimodality therapies exist, the mortality rate remains high. The hypoxic condition was one of the potent determinants in BC progression. The molecular mechanisms underpinning hypoxia and their association with BC can contribute to a better understanding of tailored therapies. In this study, two hypoxic induced BC transcriptomic cohorts (GSE27813 and GSE47533) were assessed from the GEO database. The P4HA1 gene was identified as a putative candidate and significantly regulated in hypoxic BC cells compared to normal BC cells at different time intervals (6 h, 9 h, 16 h, 32 h, and 48 h). In patients with Luminal (p < 1E-12), triple-negative subclasses (p = 1.35059E-10), Stage 1 (p = 8.8817E-16), lymph node N1 (p = 1.62436E-12), and in the 40-80 age group (p = 1.62447E-12), the expression of P4HA1 was closely associated with the clinical subtypes of BC. Furthermore, at the 10q22.1 chromosomal band, the P4HA1 gene displayed a high copy number elevation and was associated with a poor clinical regimen with overall survival, relapse-free survival, and distant metastases-free survival in BC patients. In addition, using BioGRID, the protein-protein interaction (PPI) network was built and the cellular metabolic processes, and hedgehog pathways are functionally enriched with GO and KEGG terms. This tentative result provides insight into the molecular function of the P4HA1 gene, which is likely to promote hypoxic-mediated carcinogenesis, which may favor early detection of BC and therapeutic stratification.

Inhibitory potential of Hydroxychavicol on Ehrlich ascites carcinoma model and in silico interaction on cancer targets.

Hydroxychavicol (HC), a major phenolic derivative isolated from the leaves of Piper betle L. is well known for its antibacterial, antifungal and antimutagenic properties. The present study evaluated the in vivo antitumor activity of HC against Ehrlich Ascites Carcinoma (EAC) cells in Swiss albino mice and in silico interaction of HC with the receptors involved in the cancer. Hydroxychavicol (200 and 400 mg/kg bw) was orally administered for 21 consecutive days and was effective in inhibiting the tumor growth in ascitic mouse model. HC consistently reduced the tumor volume, viable cell count, lipid peroxidation and elevated the life span of HC treated mice. Besides the hematological profiles, SGOT and SGPT levels reverted back to normal and oxidative stress markers GSH, SOD and CAT also increased in HC treated groups. In silico docking analysis revealed that HC possessed potent antagonist activity against all the cancer targets demonstrating its inhibitory activity.

Ligand-based pharmacophore mapping and virtual screening for identification of potential discoidin domain receptor 1 inhibitors.

AbbreviationsADMEabsorption, distribution, metabolism, and excretionMMGB/SAmolecular mechanics generalized born surface areaIFDinduced fit dockingRTKreceptor tyrosine kinaseNSCLCnon-small-cell lung cancerATPadenosine triphosphateOPLSoptimized potential for liquid stimulationRMSDroot mean square deviationHTVShigh-throughput virtual screeningSPstandard precisionXPextra precisionOPLS-AAoptimized potential for liquid stimulation-all atomMDmolecular simulationMMEmolecular mechanics energiesSGBsurface generalized bornPOPC membrane1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine membranePDBProtein Data BankDDR1discoidin domain receptor 1DDR2discoidin domain receptor 2DDRsdiscoidin domain receptorsECMextracellular matrixTIP4Ptransferable intermolecular potential 4 pointNPTconstant particle number, pressure and temperatureRMSFroot mean square fluctuationCommunicated by Ramaswamy H. Sarma.

Nannochloropsis Extract-Mediated Synthesis of Biogenic Silver Nanoparticles, Characterization and In Vitro Assessment of Antimicrobial, Antioxidant and Cytotoxic Activities.

Objective: To investigate the biogenic synthesis of silver nanoparticles (AgNPs) using partially purified ethyl acetate extract of Nannochloropsis sp. hexane (EAENH) fraction of microalga. Methods: The green synthesis of AgNPs was confirmed with UV-Vis spectrum which shows the surface plasmon resonance (SPR) at 421 nm. Fourier Transform Infrared Spectra (FTIR) presented the involvement of functional groups like carboxyl groups of fatty acids, tetraterpenoids of xanthophylls, hydroxyl groups of polyphenols, carbonyl and amide linkage of proteins in the AgNP synthesis. Gas Chromatography-Mass Spectrometry analysis (GCMS) revealed that phytochemicals like octadecanoic acid and hexadecanoic acid imply in capping, bioreduction, and stabilization of AgNps. Result: High-resolution Transmission electron microscope (HRTEM), Dynamic light scattering (DLS), X-ray diffraction (XRD) and EDX analysis showed the crystalline form of the AgNPs with Z-average size 57.25 nm. The zeta potential value of -25.7 mV demonstrated the negative surface charge and colloidal stability of AgNPs. The antimicrobial activity of AgNPs displayed effective inhibition zone against selected bacterial and fungal pathogens. In vitro, antioxidant effects were assessed by 1,1-diphenyl-2-picryl-hydrazyl (DPPH), hydrogen peroxide and reducing power assays which revealed excellent scavenging potential for AgNPs than the extracts. The anti-proliferative potential of biofabricated AgNPs and extracts on Human Non-small lung cancer cell line (A549) was assessed using 3­(4,5-dimethylthiazol-2-yl)-2,5- diphenyl-tetrazolium bromide (MTT) assay with IC50 values of 15 µgmL-1 and 175 µgmL-1 respectively. Conclusion: The study reveals that the microalgae-mediated AgNPs possesses potent antimicrobial and antioxidant activity along with the ability to stimulate apoptosis in A-549 cell line.

Enzyme Immobilization on Nanomaterials for Biosensor and Biocatalyst in Food and Biomedical Industry.

Enzymes exhibit a great catalytic activity for several physiological processes. Utilization of immobilized enzymes has a great potential in several food industries due to their excellent functional properties, simple processing and cost effectiveness during the past decades. Though they have several applications, they still exhibit some challenges. To overcome the challenges, nanoparticles with their unique physicochemical properties act as very attractive carriers for enzyme immobilization. The enzyme immobilization method is not only widely used in the food industry but is also a component methodology in the pharmaceutical industry. Compared to the free enzymes, immobilized forms are more robust and resistant to environmental changes. In this method, the mobility of enzymes is artificially restricted to changing their structure and properties. Due to their sensitive nature, the classical immobilization methods are still limited as a result of the reduction of enzyme activity. In order to improve the enzyme activity and their properties, nanomaterials are used as a carrier for enzyme immobilization. Recently, much attention has been directed towards the research on the potentiality of the immobilized enzymes in the food industry. Hence, the present review emphasizes the different types of immobilization methods that is presently used in the food industry and other applications. Various types of nanomaterials such as nanofibers, nanoflowers and magnetic nanoparticles are significantly used as a support material in the immobilization methods. However, several numbers of immobilized enzymes are used in the food industries to improve the processing methods which not only reduce the production cost but also the effluents from the industry.

Mitochondrial genome variations in idiopathic dilated cardiomyopathy.

Idiopathic dilated cardiomyopathy (DCM) is a structural heart disease with strong genetic background. The aim of this study was to assess the role of mitochondrial DNA (mtDNA) variations and haplogroups in Indian DCM patients. Whole mtDNA analysis of 221 DCM patients revealed 48 novel, 42 disease-associated and 97 private variations. The frequency of reported variations associated with hearing impairment, DEAF, SNHL and LHON are significantly high in DCM patients than controls. Haplogroups H and HV were over represented in DCM than controls. Functional analysis of two private variations (m.8812A>G & m.10320G>A) showed decrease in mitochondrial functions, suggesting the role of mtDNA variations in DCM.

Surface engineered Amphora subtropica frustules using chitosan as a drug delivery platform for anticancer therapy.

Drug delivery using synthetic mesoporous nanomaterials, including porous silicon, has been extensively used to ameliorate the constraints currently experienced with conventional chemotherapy. Owing to the amazing potential, the silica based nanomaterials have been used widely. Nevertheless, synthetic nanomaterial involves high cost, lack of scalability, and the use of toxic substances limits its utilization. These issues can be overcome by the use of nature generated nanoscale materials, such as diatoms would serve as a boon for pharmaceutical industries. In this study we investigate the use of a mesoporous, biodegradable nanomaterial obtained from the natural silica found in the diatom species Amphora subtropica (AMPS) for drug delivery applications. AMPS cultures cleaned and chemically treated to obtain Amphora frustules (exoskeleton) (AF), followed by surface functionalization with chitosan (Chi). Results of our experiments demonstrate high drug loading, strong luminescence, biodegradable and biocompatible nature of the doxorubicin tethered diatom. Further, toxicity studies employing immortalized lung cancer cell line (A549) indicates sustained drug delivery and less toxic compared to the free doxorubicin (DOX), suggesting AF could be an excellent substitute for synthetic nanomaterials used in drug delivery applications.

Somatic Bi-allelic Loss of TSC Genes in Eosinophilic Solid and Cystic Renal Cell Carcinoma.

Renal cell carcinomas (RCC) with overlapping histomorphologic features poses diagnostic challenges. This is exemplified in RCCs with eosinophilic cytoplasm that include eosinophilic solid and cystic RCC (ESC RCC), RCCs in germline aberrations of tuberous sclerosis complex (TSC) genes mutated (TSC RCC) individuals, and other RCC subtypes. We used next-generation sequencing (NGS) technology to molecularly profile seven ESC RCC tumors. Mutational and copy number analysis of NGS data revealed mutually exclusively somatic bi-allelic loss of TSC1 or TSC2 genes-both negative regulators of the mammalian target of rapamycin (mTOR) pathway in 85% (6/7) of evaluated cases. Thus, lack of germline TSC aberration in matched non-neoplastic renal parenchyma distinguishes ESC RCC from TSC RCC. Immunohistochemistry data shows mTOR pathway activation in all tumors, thus supporting a pathognomonic role for TSC aberrations in ESC RCC. Our study clarifies the molecular identity of ESC RCC, provides basis for the revision of current RCC classification, and may guide future therapeutic strategies. PATIENT SUMMARY: Molecular characterization of eosinophilic solid and cystic renal cell carcinomas (ESC RCC) revealed recurrent and mutually exclusive somatic homozygous loss of tuberous sclerosis complex family genes. This observation provides greater insight into the unique biology of this novel type of tumor and potentially expands the therapeutic options for ESC RCC patients.

Hypoxia stimulates microenvironment in human embryonic stem cell through inflammatory signalling: An integrative analysis.

Despite, several lines of evidence suggesting the possible role of hypoxia in stem cell development and differentiation its significance in conferring the stemness and pluripotency remains elusive. In the present study we sought to delineate the candidate genes and molecular pathways imposed during hypoxic microenvironment and its physiological relevance in tipping the balance between the niche and cellular differentiation. Integrated meta-analysis was performed between the hypoxia exposed and normal human embryonic stem cells, employing three transcriptomic cohorts (GSE35819, GSE9510 and GSE37761) retrieved from Gene expression omnibus (GEO) database. Results reveal that a total number of 12 genes were consistently differentially expressed (6up regulated and 6 down regulated) with FDR <0.05 and fold change >1.5. The Gene Ontology (GO) functions and Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis was performed using DAVID. The GO analysis showed DEG significantly enriched in terms of Cellular process (GO:0009987), protein binding (GO:0005515) and cell part (GO:0044464). KEGG analysis indicated participation of genes associated with circadian rthyum regulation and PPAR signalling pathway. Further, gene-set signature (MsigDB) enrichment analysis showed positive regulation with inflammatory signals and negative association with PPAR and p53 pathway. Protein-protein network of gene modules suggests significant hub proteins viz. CTTNB1 (Degree = 18), IL8 (Degree = 15), NFKB1 (Degree = 15) and RELA (Degree = 15) in the PPI network. MCODE algorithm was used for subnetworks of the PPI network. Our integrative analysis documents the potential candidate genes which serves distinct roles influencing metabolic shift and induce inflammatory effectors contributing to hypoxic mediated stem cell niche.

Gold and Silver Nanoparticles Biomimetically Synthesized Using Date Palm Pollen Extract-Induce Apoptosis and Regulate p53 and Bcl-2 Expression in Human Breast Adenocarcinoma Cells.

Recently, several attempts have been made to use the phytopharmaceuticals from plant extracts as reducing, capping and stabilizing agents for the biomimetic synthesis of various metal nanoparticles conjugated to the phytopharmaceuticals. These biogenic metal nanoparticles are non-toxic and can be used as contrast agents, drug delivery vehicles and photothermal agents for cancer therapy. Herein, we report the synthesis of both silver and gold nanoparticles using the pollen extract of Phoenix dactylifera (Date Palm), characterization using UV-visible spectroscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy, quantitation of phytochemicals capping the nanoparticles using Folin - Ciocalteu's method, cytotoxicity studies on MCF-7 breast cancer cells, cancer cell death analysis using fluorescent microscopy, and modulation of expression of the pro-apoptotic p53 and anti-apoptotic Bcl-2 proteins. The biosynthesis resulted in stable and poly-dispersed silver nanoparticles and gold nanoparticles, exhibiting strong and broad surface plasmon absorption peaks. The elemental analysis confirmed the presence of gold and silver of high purity and also the organic moieties from the plant extract acting as capping and stabilizing agents. The biogenic nanoparticles also exhibited dose-dependent cytotoxicity on MCF-7 cells and showed signs of apoptotic cell death. Immunoassays revealed the upregulation of the pro-apoptotic protein p53 and down-regulation of the anti-apoptotic protein Bcl-2 after the nanoparticle treatment.

Biallelic Alteration and Dysregulation of the Hippo Pathway in Mucinous Tubular and Spindle Cell Carcinoma of the Kidney.

Mucinous tubular and spindle cell carcinoma (MTSCC) is a relatively rare subtype of renal cell carcinoma (RCC) with distinctive morphologic and cytogenetic features. Here, we carry out whole-exome and transcriptome sequencing of a multi-institutional cohort of MTSCC (n = 22). We demonstrate the presence of either biallelic loss of Hippo pathway tumor suppressor genes (TSG) and/or evidence of alteration of Hippo pathway genes in 85% of samples. PTPN14 (31%) and NF2 (22%) were the most commonly implicated Hippo pathway genes, whereas other genes such as SAV1 and HIPK2 were also involved in a mutually exclusive fashion. Mutations in the context of recurrent chromosomal losses amounted to biallelic alterations in these TSGs. As a readout of Hippo pathway inactivation, a majority of cases (90%) exhibited increased nuclear YAP1 protein expression. Taken together, nearly all cases of MTSCC exhibit some evidence of Hippo pathway dysregulation. SIGNIFICANCE: MTSCC is a rare and relatively recently described subtype of RCC. Next-generation sequencing of a multi-institutional MTSCC cohort revealed recurrent chromosomal losses and somatic mutations in the Hippo signaling pathway genes leading to potential YAP1 activation. In virtually all cases of MTSCC, there was evidence of Hippo pathway dysregulation, suggesting a common mechanistic basis for this disease. Cancer Discov; 6(11); 1258-66. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 1197.

Impact of Anthocyanidins on Mitoxantrone-Induced Cytotoxicity and Genotoxicity: An In Vitro and In Vivo Analysis.

Hypothesis Anthocyanins possess well-known biological effects and suppress DNA damage induced by therapeutic topoisomerase poisons. Our study focusses on the modulatory effects of anthocyanidins-malvidin (MAL) and pelargonidin (PEL)-on topoisomerase II poison mitoxantrone (MXT)-induced cytotoxicity and genotoxicity in in vitro and in vivo conditions. Study design HepG2 cells were treated with MXT (1-10 µM), MAL (10-100 µM,) and PEL (5-640 µM) to determine cell viability. Further, experiments on cytotoxicity and apoptosis induction by single agents or combinations were performed. In vitro and in vivo antigenotoxic effect of MAL/PEL against MXT was evaluated in human lymphocytes and mouse bone marrow cells. Methods Cytotoxicity of test agents and apoptosis induction in HepG2 cells was assessed by MTT assay, trypan blue dye exclusion assay and Hoechst 33258 staining. Antigenotoxic effects of MAL/PEL against MXT were assessed in co-treated human lymphocytes and bone marrow from mice that received MXT intraperitoneally 30 minutes post MAL/PEL oral administration Results Dose-dependent cytotoxicity was observed with all 3 test agents in HepG2 cells. Highest test concentration of 100 µM MAL, 640 µM PEL, and 10 µM MXT decreased HepG2 cell viability by 80%, 30%, and 90%, respectively. The combination of 1 µM MXT + 80 µM MAL reduced cell viability better than single agents. MAL/PEL treatment significantly reduced MXT-induced genotoxicity in human lymphocytes and micronuclei formation in mice. Conclusion Combination of MAL/PEL with lower doses of MXT, especially MAL+MXT increases the cytotoxicity in cancer cells. In addition, MXT treatment with MAL/PEL reduced MXT-induced genotoxicity and protected normal cells during chemotherapy.

Nomadic genetic elements contribute to oncogenic translocations: Implications in carcinogenesis.

Chromosomal translocations as molecular signatures have been reported in various malignancies but, the mechanism behind which is largely unknown. Swapping of chromosomal fragments occurs by induction of double strand breaks (DSBs), most of which were initially assumed de novo. However, decoding of human genome proved that transposable elements (TE) might have profound influence on genome integrity. TEs are highly conserved mobile genetic elements that generate DSBs, subsequently resulting in large chromosomal rearrangements. Previously TE insertions were thought to be harmless, but recently gains attention due to the origin of spectrum of post-insertional genomic alterations and subsequent transcriptional alterations leading to development of deleterious effects mainly carcinogenesis. Though the existing knowledge on the cancer-associated TE dynamics is very primitive, exploration of underlying mechanism promises better therapeutic strategies for cancer. Thus, this review focuses on the prevalence of TE in the genome, associated genomic instability upon transposition activation and impact on tumorigenesis.

Low-dose chemotherapeutic drugs induce reactive oxygen species and initiate apoptosis-mediated genomic instability.

Prolonged cancer cell survival, acquiring drug resistance, and secondary cancer development despite chemotherapy are the major challenges during cancer treatment, whose underlying mechanism still remains elusive. In this study, low-doses of chemotherapeutic drugs (LDCD) - doxorubicin (DOX), etoposide (ETOP), and busulfan (BUS) were used to ascertain the effect of residual concentrations of drugs on breast cancer cells. Our results showed that exposure to LDCD caused significant induction of ROS, early signs of apoptosis and accumulation of cells in S and G2-M phases of the cell cycle in MCF-7 and MDA-MB-231 cell lines. Under drug-free recovery conditions, a decrease in the number of apoptotic cells and an increase in the number of colonies formed were observed. Analysis of the molecular mechanism showed lower expression of cleaved products of caspase 3, 9, PARP and occurrence of DNA strand breaks in recovered cells compared to LDCD-treated cells, suggesting incomplete cell death activation and survival of cells with genomic damage after therapeutic insult. Thus, LDCD induces defective apoptosis in cancer cells allowing a small population of cells to escape from cell cycle check points and survive with accumulated genetic damage that could eventually result in secondary cancers that warrants further studies for better therapeutic strategies.

Doxorubicin loaded polymeric gold nanoparticles targeted to human folate receptor upon laser photothermal therapy potentiates chemotherapy in breast cancer cell lines.

The current research focuses on the application of folate conjugated and doxorubicin loaded polymeric gold nanoparticles (GNPs) for the targeted treatment of folate receptor overexpressing breast cancers, augmented by adjunctive laser photothermal therapy. Herein, GNPs surface modified with folate, drug doxorubicin and polyethylene glycol were engineered and were used as vehicles for folate receptor targeted delivery of doxorubicin into cancer cells. Subsequently, the GNPs were photo-excited using laser light for mediating hyperthermia in the cancer cells. In vitro studies were performed to validate the efficacy of the combined modality of folate conjugated and doxorubicin loaded polymeric GNP mediated chemotherapy followed by photothermal therapy in comparison to treatment with free drug; and the combination modality showed better therapeutic efficacy than that of plain doxorubicin treatment in MDA-MB-231 breast cancer cells that express increased levels of surface folate receptors when compared to MCF-7 breast cancer cells that express low levels of folate receptor. The mechanism of cell death was investigated using fluorescent microscopy. Immunoassays showed the up-regulation of the pro-apoptotic protein p53 and down-regulation of the anti-apoptotic protein Bcl-2. Collectively, these results suggest that the folate tagged doxorubicin loaded GNPs are an attractive platform for targeted delivery of doxorubicin and are agents suitable for photothermal cancer therapy.

Near infra-red laser mediated photothermal and antitumor efficacy of doxorubicin conjugated gold nanorods with reduced cardiotoxicity in swiss albino mice.

Development of a multifunctional drug delivering system without side effects and compromising its therapeutic efficacy is a major concern in anticancer research. Recently, we have developed and demonstrated doxorubicin conjugated gold nanorod (DOX@PSS-GNR) as a sustained drug delivery vehicle. Here, we investigate the biodistribution, antitumor and photothermal efficacy of DOX@PSS-GNR along with its potential impact on cardiotoxicity in in vivo. The studies revealed that the accumulation of Free DOX in myocardium was 4-fold reduced in DOX@PSS-GNR animals, which further minimizes its cardiotoxicity by decreasing cardiac injury via preservation of cardiac markers. Further, DOX@PSS-GNR exhibits effective antitumor efficacy against Dalton lymphoma ascites (DLA) as evidenced by cell cycle analysis, apoptotic signals and reduced tumor volume and weight. In addition, DOX@PSS-GNR exhibits higher photothermal response and dominates DLA growth upon 0.1 W/cm(2) laser irradiation. In conclusion, multifunctional DOX@PSS-GNR with improved therapeutic index and reduced cardiotoxicity represents a promising candidate for cancer treatment. FROM THE CLINICAL EDITOR: Doxorubicin is a widely used agent for cancer therapy. However, the side effects are still significant, despite the development of liposomal formulation. In this study, the authors investigated the use of doxorubicin conjugated gold nanorods (DOX@PSS-GNR) in terms of biodistribution, antitumor activity and systemic side effects. The much reduced cardiotoxicity of the new delivery system should provide an improved agent for future clinical use.