Cancer Chemotherapeutic Drugs Research Articles

An ABCG2 non-substrate anticancer agent FL118 targets drug-resistant cancer stem-like cells and overcomes treatment resistance of human pancreatic cancer

BackgroundPancreatic cancer is a deadly disease with a very low 5-year patient survival rate of 6–8%. The major challenges of eliminating pancreatic cancer are treatment resistance and stromal barriers to optimal drug access within the tumor. Therefore, effective molecular targeting drugs with high intra-tumor access and retention are urgently needed for managing this devastating disease in the clinic.MethodsThis study has used the following in vitro and in vivo techniques for the investigation of exceptional anticancer drug FL118’s efficacy in treatment of resistant pancreatic cancer: cell culture; immunoblotting analysis to test protein expression; DNA sub-G1 flow cytometry analyses to test cell death; MTT assay to test cell viability; pancreatic cancer stem cell assays (fluorescence microscopy tracing; matrigel assay; CD44-positive cell colony formation assay); human luciferase-labeled pancreatic tumor orthotopic animal model in vivo imaging; pancreatic cancer patient-derived xenograft (PDX) animal models; and toxicology studies with immune-competent BALB/cj mice and beagle dogs.ResultsOur studies found that FL118 alone preferentially killed cisplatin-resistant cancer cells, while a combination of FL118 with cisplatin synergistically killed resistant pancreatic cancer cells and reduced spheroid formation of treatment-resistant pancreatic cancer stem-like cells. Furthermore, using in vivo-imaging, we found that FL118 in combination with cisplatin strongly inhibited both drug-resistant pancreatic xenograft tumor growth and metastasis. In PDX model, we demonstrated that FL118 alone effectively eliminated PDX tumors, while FL118 in combination with gemcitabine eliminated PDX tumors that showed relative resistance (less sensitivity) to treatment with FL118. These FL118 efficacy results are consistent with our molecular-targeting data showing that FL118 inhibited the expression of multiple antiapoptotic proteins (survivin, Mcl-1, XIAP, cIAP2) and ERCC6, a critical regulator of DNA repair, in treatment-resistant pancreatic stem-like cancer cells. Furthermore, FL118 toxicity studies in BALB/cj mice and beagle dogs indicated that FL118 exhibits favorable hematopoietic and biochemical toxicities.ConclusionTogether, our studies suggest that FL118 is a promising anticancer drug for further clinical development to effectively treat drug-resistant pancreatic cancer alone or in combination with other pancreatic cancer chemotherapeutic drugs.

Intravital imaging of adriamycin-induced renal pathology using two-photon microscopy and optical coherence tomography

Adriamycin (doxorubicin), a common cancer chemotherapeutic drug, can be used to induce a model of chronic progressive glomerular disease in rodents. In our studies, we evaluated renal changes in a rat model after Adriamycin injection using two-photon microscopy (TPM), optical coherence tomography (OCT) and Doppler OCT (DOCT). Taking advantage of deep penetration and fast scanning speed for three-dimensional (3D) label-free imaging, OCT/DOCT system was able to reveal glomerular and tubular pathology noninvasively and in real time. By imaging renal pathology following the infusion of fluorophore-labeled dextrans of different molecular weights, TPM can provide direct views of glomerular and tubular flow dynamics with the onset and progression of renal disease. Specifically, glomerular permeability and filtration, proximal and distal tubular flow dynamics can be revealed. 6–8 weeks after injection of Adriamycin, TPM and OCT/DOCT imaging revealed glomerular sclerosis, compromised flow across the glomerular wall, tubular atrophy, tubular dilation, and variable intra-tubular flow dynamics. Our results indicate that TPM and OCT/DOCT provide real-time imaging of renal pathology in vivo that has not been previously available using conventional microscopic procedures.

Tdp1 processes chromate-induced single-strand DNA breaks that collapse replication forks.

Hexavalent chromium [Cr(VI)] damages DNA and causes cancer, but it is unclear which DNA damage responses (DDRs) most critically protect cells from chromate toxicity. Here, genome-wide quantitative functional profiling, DDR measurements and genetic interaction assays in Schizosaccharomyces pombe reveal a chromate toxicogenomic profile that closely resembles the cancer chemotherapeutic drug camptothecin (CPT), which traps Topoisomerase 1 (Top1)-DNA covalent complex (Top1cc) at the 3’ end of single-stand breaks (SSBs), resulting in replication fork collapse. ATR/Rad3-dependent checkpoints that detect stalled and collapsed replication forks are crucial in Cr(VI)-treated cells, as is Mus81-dependent sister chromatid recombination (SCR) that repairs single-ended double-strand breaks (seDSBs) at broken replication forks. Surprisingly, chromate resistance does not require base excision repair (BER) or interstrand crosslink (ICL) repair, nor does co-elimination of XPA-dependent nucleotide excision repair (NER) and Rad18-mediated post-replication repair (PRR) confer chromate sensitivity in fission yeast. However, co-elimination of Tdp1 tyrosyl-DNA phosphodiesterase and Rad16-Swi10 (XPF-ERCC1) NER endonuclease synergistically enhances chromate toxicity in top1Δ cells. Pnk1 polynucleotide kinase phosphatase (PNKP), which restores 3’-hydroxyl ends to SSBs processed by Tdp1, is also critical for chromate resistance. Loss of Tdp1 ameliorates pnk1Δ chromate sensitivity while enhancing the requirement for Mus81. Thus, Tdp1 and PNKP, which prevent neurodegeneration in humans, repair an important class of Cr-induced SSBs that collapse replication forks.

The Influence of Nicotine on Lung Tumor Growth, Cancer Chemotherapy, and Chemotherapy-Induced Peripheral Neuropathy.

Studies in animal models have suggested that nicotine, an agonist of nicotinic acetylcholine receptors, may have the potential to prevent and/or reverse the peripheral neuropathy induced by cancer chemotherapeutic drugs, such as paclitaxel and oxaliplatin. However, a large body of evidence suggests that nicotine may also stimulate lung tumor growth and/or interfere with the effectiveness of cancer chemotherapy. Whereas the reported proliferative effects of nicotine are highly variable, the antagonism of antitumor drug efficacy is more consistent, although this latter effect has been demonstrated primarily in cell culture studies. In contrast, in vitro and in vivo studies from our own laboratory indicate that nicotine fails to enhance the growth of nonsmall cell lung cancer cells or attenuate the effects of chemotherapy (paclitaxel). Given the inconsistencies in the literature, coupled with our own findings, the weight of evidence suggests that caution may be warranted in proposing to use nicotine to mitigate chemotherapy-induced peripheral neuropathy in cancer patients receiving chemotherapy. Conversely, clinical trials could be performed in patients who have completed therapy and are considered to be disease-free to determine whether nicotine, in the form of commercially available patches or gum, is effective in alleviating peripheral neuropathy symptoms.

Variable termination sites of DNA polymerases encountering a DNA-protein cross-link.

DNA-protein cross-links (DPCs) are important DNA lesions induced by endogenous crosslinking agents such as formaldehyde or acetaldehyde, as well as ionizing radiation, cancer chemotherapeutic drugs, and abortive action of some enzymes. Due to their very bulky nature, they are expected to interfere with DNA and RNA synthesis and DNA repair. DPCs are highly genotoxic and the ability of cells to deal with them is relevant for many chemotherapeutic interventions. However, interactions of DNA polymerases with DPCs have been poorly studied due to the lack of a convenient experimental model. We have used NaBH4-induced trapping of E. coli formamidopyrimidine-DNA glycosylase with DNA to construct model DNA polymerase substrates containing a DPC in single-stranded template, or in the template strand of double-stranded DNA, or in the non-template (displaced) strand of double-stranded DNA. Nine DNA polymerases belonging to families A, B, X, and Y were studied with respect to their behavior upon encountering a DPC: Klenow fragment of E. coli DNA polymerase I, Thermus aquaticus DNA polymerase I, Pyrococcus furiosus DNA polymerase, Sulfolobus solfataricus DNA polymerase IV, human DNA polymerases β, κ and λ, and DNA polymerases from bacteriophages T4 and RB69. Although none were able to fully bypass DPCs in any context, Family B DNA polymerases (T4, RB69) and Family Y DNA polymerase IV were able to elongate the primer up to the site of the cross-link if a DPC was located in single-stranded template or in the displaced strand. In other cases, DNA synthesis stopped 4–5 nucleotides before the site of the cross-link in single-stranded template or in double-stranded DNA if the polymerases could displace the downstream strand. We suggest that termination of DNA polymerases on a DPC is mostly due to the unrelieved conformational strain experienced by the enzyme when pressing against the cross-linked protein molecule.

Advancements in the oral delivery of Docetaxel: challenges, current state-of-the-art and future trends.

The oral delivery of cancer chemotherapeutic drugs is challenging due to low bioavailability, gastrointestinal side effects, first-pass metabolism and P-glycoprotein efflux pumps. Thus, chemotherapeutic drugs, including Docetaxel, are administered via an intravenous route, which poses many disadvantages of its own. Recent advances in pharmaceutical research have focused on designing new and efficient drug delivery systems for site-specific targeting, thus leading to improved bioavailability and pharmacokinetics. A decent number of studies have been reported for the safe and effective oral delivery of Docetaxel. These nanocarriers, including liposomes, polymeric nanoparticles, metallic nanoparticles, hybrid nanoparticles, dendrimers and so on, have shown promising results in research papers and clinical trials. The present article comprehensively reviews the research efforts made so far in designing various advancements in the oral delivery of Docetaxel. Different strategies to improve oral bioavailability, prevent first-pass metabolism and inhibition of efflux pumping leading to improved pharmacokinetics and anticancer activity are discussed. The final portion of this review article presents key issues such as safety of nanomaterials, regulatory approval and future trends in nanomedicine research.

Cisplatin-DNA adduct repair of transcribed genes is controlled by two circadian programs in mouse tissues

Cisplatin is a major cancer chemotherapeutic drug. It kills cancer cells by damaging their DNA, mainly in the form of Pt-d(GpG) diadducts. However, it also has serious side effects, including nephrotoxicity and hepatotoxicity that limit its usefulness. Chronotherapy is taking circadian time into account during therapy to improve the therapeutic index, by improving efficacy and/or limiting toxicity. To this end, we tested the impact of clock time on excision repair of cisplatin-induced DNA damage at single-nucleotide resolution across the genome in mouse kidney and liver. We found that genome repair is controlled by two circadian programs. Repair of the transcribed strand (TS) of active, circadian-controlled genes is dictated by each gene's phase of transcription, which falls across the circadian cycle with prominent peaks at dawn and dusk. In contrast, repair of the nontranscribed strand (NTS) of all genes, repair of intergenic DNA, and global repair overall peaks at Zeitgeber time ZT08, as basal repair capacity, which is controlled by the circadian clock, peaks at this circadian time. Consequently, the TS and NTS of many genes are repaired out of phase. As most cancers are thought to have defective circadian rhythms, these results suggest that future research on timed dosage of cisplatin could potentially reduce damage to healthy tissue and improve its therapeutic index.

The Interaction of the Metallo-Glycopeptide Anti-Tumour Drug Bleomycin with DNA.

The cancer chemotherapeutic drug, bleomycin, is clinically used to treat several neoplasms including testicular and ovarian cancers. Bleomycin is a metallo-glycopeptide antibiotic that requires a transition metal ion, usually Fe(II), for activity. In this review, the properties of bleomycin are examined, especially the interaction of bleomycin with DNA. A Fe(II)-bleomycin complex is capable of DNA cleavage and this process is thought to be the major determinant for the cytotoxicity of bleomycin. The DNA sequence specificity of bleomycin cleavage is found to at 5′-GT* and 5′-GC* dinucleotides (where * indicates the cleaved nucleotide). Using next-generation DNA sequencing, over 200 million double-strand breaks were analysed, and an expanded bleomycin sequence specificity was found to be 5′-RTGT*AY (where R is G or A and Y is T or C) in cellular DNA and 5′-TGT*AT in purified DNA. The different environment of cellular DNA compared to purified DNA was proposed to be responsible for the difference. A number of bleomycin analogues have been examined and their interaction with DNA is also discussed. In particular, the production of bleomycin analogues via genetic manipulation of the modular non-ribosomal peptide synthetases and polyketide synthases in the bleomycin gene cluster is reviewed. The prospects for the synthesis of bleomycin analogues with increased effectiveness as cancer chemotherapeutic agents is also explored.

(Invited) Carbon Nanotube Photoluminescence Spectroscopy for Applications in Cancer Research

The detection of biomarkers and drugs in live cells and animals would allow for more effective studies of the dynamics of cancer and treatment. Toward these ends, single-walled carbon nanotube photoluminescence is suitable for measurements in live cells and in vivo, and nanotube near-infrared emission exhibits sensitivity to the local environment via solvatochromic responses. We developed new optical instrumentation to image carbon nanotubes and to measure spectral changes of carbon nanotube photoluminescence in live cells and animals. Concomitantly, we developed new methods to exacerbate the nanotube emission response to produce large spectral shifts (> 14 nm) upon the binding of cancer biomarkers and chemotherapeutic drugs. The ability to improve measurements and control of carbon nanotube solvatochromism may improve sensitivity and selectivity of nanosensors and potentially expand the application of nanotube-based optical measurements to new classes of bioanalytes.

Genetic Ablation of the ABC Transporter Abcc4 Impairs Lymphoid Leukemogenesis

ABCC4 is an ABC transporter of the C sub‐family that is ubiquitously expressed and exports key endogenous compounds including cAMP and prostaglandins, and cancer chemotherapeutic drugs. cAMP and prostaglandins are signaling molecules that, among other functions, regulate thymocyte development and function. Thymocyte progenitors, IL7 receptor positive cells, migrate from the bone marrow to the thymus and give rise to mature T‐cells. The maturation of thymocytes can be followed by monitoring for the presence of surface markers CD4 and CD8. Briefly, thymocytes are initially double negative (DN) cells, with neither CD4 nor CD8; after T‐cell receptor rearrangement, CD4 and CD8 are expressed on double positive cells (DP), which following positive and negative selection, become mature, single positive (SP) cells expressing either CD4 or CD8. Abcc4 is highly expressed in DP and CD4‐positve thymocytes, while being undetectable in DN thymocytes from wild‐type (WT) mice, suggesting a developmental regulation of Abcc4. Therefore, we hypothesized that ablation of Abcc4 from mice would lead to aberrant T‐cell development and function.ABCC4 absence had no measureable impact on the number of hematopoietic progenitors. We hypothesized that lymphoid progenitors in Abcc4‐knockout(KO) mice may have an impaired leukemogenesis potential. To test this hypothesis, hematopoietic progenitors from Abcc4‐KO or WT mice were transduced with a retrovirus harboring a MYCN cDNA, a known driver of lymphoid leukemia, and subsequently transplanted into lethally irradiated congenic WT recipient mice. Mice transplanted with either WT or Abcc4‐KO MYCN‐transduced hematopoietic progenitors developed both B‐ and T‐cell leukemia, with tumors expressing Abcc4 on the plasma membrane. Kaplan‐Meier survival analysis revealed that mice transduced with Abcc4‐KO progenitors had a dramatic increase in median survival from 81.5 days in mice who received WT progenitors to 112 days in mice who received Abcc4‐KO progenitors. These studies suggested the lymphoid progenitors from Abcc4‐KO mice harbored an intrinsic defect manifested by reduced lymphoid leukemia. This was further investigated by performing a competitive bone‐marrow transplantation experiment. Briefly, hematopoietic progenitors from Abcc4‐KO and wildtype mice were isolated and mixed in equal numbers (each harboring a different surface marker to enable identification), then transplanted into congenic wildtype mice following lethal irradiation; subsequently the differentiated lymphoid progeny were identified in the peripheral blood. These studies revealed that the number of CD4+ cells from Abcc4‐KO donors was reduced, thus confirming a defect in Abcc4‐KO lymphoid progenitors. A defect in peripheral thymocyte function is also a potential mechanism, as genes in the arachidonic acid pathway regulate further differentiation and function of mature thymocytes. We discovered altered expression of genes in the arachidonic acid pathway such as Cox‐1 and Ptger4, when compared to age‐matched WT mice. These data suggest that genetic ablation of Abcc4 has an effect on arachidonic acid signaling, which may in turn affect thymocyte function.Overall, the data presented herein suggest that ABCC4 impacts lymphoid progenitors and differentiated thymocytes. One implication of these findings is that deficiency or insufficiency of ABCC4 may reduce the possibility of developing lymphoid malignancies.Support or Funding InformationThis work was funded by NIH and ALSACThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

A UHPLC–MS/MS-based method for the simultaneous monitoring of eight antiblastic drugs in plasma and urine of exposed healthcare workers

Exposure of healthcare workers to anticancer drugs requires the combined action of environmental and biological monitoring to assess the effective level of exposure to these chemicals, to improve awareness and to avoid adverse health effects on this category of workers. Cancer chemotherapeutic drugs show different mechanisms of action due to diverse chemical structures; consequently, they differ in hydrophobicity, pharmacokinetics and pharmacodynamics. Therefore, the appearance, accumulation and elimination of each of these molecules in body fluids and tissues might be extremely variable; this prompts the need for a rapid and versatile analytical protocol for the biological monitoring of possible exposure of workers involved in the manipulation, administration and disposal of cancer chemotherapeutic drugs. In this paper we describe the development, optimization and validation of a UHPLC–MS/MS method for the simultaneous quasi-quantitative analysis of eight widely used antineoplastic drugs, which can be used for the analysis of both urine and blood samples. This methodology was applied to the biological monitoring of healthcare workers exposed to different extents to antiblastic drugs at the University Hospital “San Giovanni di Dio e Ruggi d’Aragona” in Salerno (Italy), and allowed to identify two subjects exposed to irinotecan out of a total of fifteen workers analyzed.

Immunogenic chemotherapy: Dose and schedule dependence and combination with immunotherapy

Conventional cytotoxic cancer chemotherapy is often immunosuppressive and associated with drug resistance and tumor regrowth after a short period of tumor shrinkage or growth stasis. However, certain cytotoxic cancer chemotherapeutic drugs, including doxorubicin, mitoxantrone, and cyclophosphamide, can kill tumor cells by an immunogenic cell death pathway, which activates robust innate and adaptive anti-tumor immune responses and has the potential to greatly increase the efficacy of chemotherapy. Here, we review studies on chemotherapeutic drug-induced immunogenic cell death, focusing on how the choice of a conventional cytotoxic agent and its dose and schedule impact anti-tumor immune responses. We propose a strategy for effective immunogenic chemotherapy that employs a modified metronomic schedule for drug delivery, which we term medium-dose intermittent chemotherapy (MEDIC). Striking responses have been seen in preclinical cancer models using MEDIC, where an immunogenic cancer chemotherapeutic agent is administered intermittently and at an intermediate dose, designed to impart strong and repeated cytotoxic damage to tumors, and on a schedule compatible with activation of a sustained anti-tumor immune response, thereby maximizing anti-cancer activity. We also discuss strategies for combination chemo-immunotherapy, and we outline approaches to identify new immunogenic chemotherapeutic agents for drug development.

Tumor necrosis factor-related apoptosis inducing ligand overexpression and Taxol treatment suppresses the growth of cervical cancer cells in vitro and in vivo.

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) is a member of tumor necrosis factor (TNF) superfamily and functions to promote apoptosis by binding to cell surface death receptor (DR)4 and DR5. Cancer cells are more sensitive than normal cells to TRAIL-induced apoptosis, and TRAIL-based therapeutic strategies have shown promise for the treatment of cancer. The present study investigated whether enforced overexpression of TRAIL in cervical cancer cells promoted cell death in the presence or absence of Taxol, an important first-line cancer chemotherapeutic drug. Hela human cervical cancer cells were transfected with a TRAIL expression plasmid, and the effects of the combination treatment with Taxol on apoptosis was investigated in vitro and in tumor xenografts in vivo. The results indicated that Taxol treatment and TRAIL overexpression enhanced apoptosis compared with either treatment alone. The present data indicate that Taxol may enhance the pro-apoptotic effects of TRAIL overexpression in HeLa cells by increasing cleaved caspase-3 and DR5 expression levels and decreasing Bcl-2 expression levels. Furthermore, the findings suggest a possible novel treatment option for cervical cancer and uncovers a potential mechanism of the enhancing effects of Taxol on TRAIL-induced apoptosis.

Leveraging Epigenetics to Enhance the Cellular Response to Chemotherapies and Improve Tumor Immunogenicity.

Cancer chemotherapeutic drugs have greatly advanced our ability to successfully treat a variety of human malignancies. The different forms of stress produced by these agents in cancer cells result in both cell autonomous and cell nonautonomous effects. Desirable cell autonomous effects include reduced proliferative potential, cellular senescence, and cell death. More recently recognized cell nonautonomous effects, usually in the form of stimulating an antitumor immune response, have significant roles in therapeutic efficiency for a select number of chemotherapies. Unfortunately, the success of these therapeutics is not universal as not all tumors respond to treatment, and those that do respond will frequently relapse into therapy-resistant disease. Numerous strategies have been developed to sensitize tumors toward chemotherapies as a means to either improve initial responses, or serve as a secondary treatment strategy for therapy-resistant disease. Recently, targeting epigenetic regulators has emerged as a viable method of sensitizing tumors to the effects of chemotherapies, many of which are cytotoxic. In this review, we summarize these strategies and propose a path for future progress.

Phthalate exposure promotes chemotherapeutic drug resistance in colon cancer cells.

Phthalates are widely used as plasticizers. Humans can be exposed to phthalates through ingestion, inhalation, or treatments that release di(2-ethylhexyl) phthalate (DEHP) and its metabolite, mono(2-ehylhexyl) phthalate (MEHP), into the body from polyvinyl chloride-based medical devices. Phthalate exposure may induce reproductive toxicity, liver damage, and carcinogenesis in humans. This study found that colon cancer cells exposed to DEHP or MEHP exhibited increased cell viability and increased levels of P-glycoprotein, CD133, Bcl-2, Akt, ERK, GSK3β, and β-catenin when treated with oxaliplatin or irinotecan, as compared to control. The P-glycoprotein inhibitor, tariquidar, which blocks drug efflux, reduced the viability of DEHP- or MEHP-treated, anti-cancer drug-challenged cells. DEHP or MEHP treatment also induced colon cancer cell migration and epithelial-mesenchymal transformation. Elevated stemness-related protein levels (β-catenin, Oct4, Sox2, and Nanog) and increased cell sphere sizes indicated that DEHP- or MEHP-treated cells were capable of self-renewal. We also found that serum DEHP concentrations were positively correlated with cancer recurrence. These results suggest phthalate exposure enhances colon cancer cell metastasis and chemotherapeutic drug resistance by increasing cancer cell stemness, and that P-glycoprotein inhibitors might improve outcomes for advanced or drug-resistant colon cancer patients.

Regulation of DNA replication-coupled histone gene expression.

The expression of core histone genes is cell cycle regulated. Large amounts of histones are required to restore duplicated chromatin during S phase when DNA replication occurs. Over-expression and excess accumulation of histones outside S phase are toxic to cells and therefore cells need to restrict histone expression to S phase. Misregulation of histone gene expression leads to defects in cell cycle progression, genome stability, DNA damage response and transcriptional regulation. Here, we discussed the factors involved in histone gene regulation as well as the underlying mechanism. Understanding the histone regulation mechanism will shed lights on elucidating the side effects of certain cancer chemotherapeutic drugs and developing potential biomarkers for tumor cells.

Debugging a cancer therapy

Cancer Microbes contribute not only to the development of human diseases but also to the response of diseases to treatment. Geller et al. show that certain bacteria express enzymes capable of metabolizing the cancer chemotherapeutic drug gemcitabine into an inactive form. When bacteria were introduced into tumors growing in mice, the tumors became resistant to gemcitabine, an effect that was reversed by antibiotic treatment. Interestingly, a high percentage of human pancreatic ductal adenocarcinomas, a tumor type commonly treated with gemcitabine, contain the culprit bacteria. These correlative results raise the tantalizing possibility that the efficacy of an existing therapy for this lethal cancer might be improved by cotreatment with antibiotics. Science , this issue p. [1156][1] [1]: /lookup/doi/10.1126/science.aah5043

Need of an Ancient Roots to Modern Medicine in the Treatment of Cancer- A review

<p>The already available expensive conventional therapies for cancer like chemotherapy and radiotherapy have a number of side effects such as myelosuppression and neurological, cardiac, pulmonary, and renal toxicity, which pose serious harm to the quality of life. Therefore, there is a need to develop treatment options that include more potent and less toxic anticancer drugs as compared to existing drugs. Studies have shown that regular consumption of fruits and vegetables because of phytochemical compounds extracted from them inhibiting the activity of antioxidant and free radicals which in turn showing anti-cancer activities. More recent semi-synthetic analogues of these agents are vinorelbine (VRLB) and vindesine (VDS). These agents are primarily used in combination with other cancer chemotherapeutic drugs for the treatment of a variety of cancers. VLB is used for the treatment of leukaemia, lymphomas, advanced testicular cancer, breast and lung cancers, and Kaposi’s sarcoma, and VCR, in addition to the treatment of lymphomas, also shows efficacy against leukaemia, particularly acute lymphocytic leukaemia in childhood. VRLB has shown activity against non-small-cell lung cancer and advanced breast cancer. Therefore there is need of developing cell cycle-based, mechanism-targeted ancient based modern cancer therapies that emulate the body's natural process in order to stop the growth of cancer cells. This approach can limit the damage to normal cells and the accompanying side effects caused by conventional chemotherapeutic agents. This review focuses on the role of ancient medicine in modern research and anticancer drug development. The current findings and known anticancer agents from natural sources are discussed, and recent therapeutic advances in this field are presented.</p>

Abstract 2120: Distinct molecular effects of chemotherapeutic agents on choline phospholipid metabolism of triple-negative breast cancer cells

Abstract The magnetic resonance spectroscopy (MRS)-detected total choline (tCho) signal is a promising non-invasive surrogate marker able to predict chemotherapy response in breast cancer patients early on. However, the molecular mechanisms by which common chemotherapeutic drugs affect the tCho signal, which consists of glycerophosphocholine (GPC), phosphocholine (PC), and free choline (Cho), are mostly unknown. Here we have employed some widely used cancer chemotherapeutic drugs such as doxorubicin, paclitaxel, and vinorelbine to treat triple-negative human MDA-MB-231 breast cancer cells to elucidate their molecular effects on choline phospholipid metabolism. High-resolution (HR) 1H MRS of water-soluble cell extracts was employed to detect changes in cellular choline metabolite profiles, and quantitative RT-PCR (qRT-PCR) to assess the corresponding changes in the expression levels of choline-metabolizing enzymes. After 48 hours of doxorubicin treatment, the GPC levels in MDA-MB-231 cells significantly increased, while PC level decreased, and the tCho concentration remained unchanged. Vinorelbine treatment displayed a comparable effect to doxorubicin, but the GPC increase and PC decrease occurred to a lesser extent. Paclitaxel treatment caused an increased GPC level along with an unaltered PC level, leading to a slightly increased tCho level. In all these cases, the PC/GPC ratio decreased from 3.5 in the control to about 2.0 in paclitaxel- or vinorelbine-treated samples, to about 1.0 in doxorubicin-treated samples. qRT-PCR-detected mRNA expression levels showed that GDPD6 and Chkα were downregulated by doxorubicin. GDPD5, GDPD6, and Chkα genes displayed a reduced mRNA expression level following vinorelbine treatment, while no significant change in these three genes was detected after paclitaxel treatment. For comparison, the known GDPD6 inhibitor dipyridamole significantly increased cellular GPC levels, but, as expected, did not affect GDPD6 mRNA expression levels as it acts as an enzyme inhibitor. Our study demonstrates that choline containing metabolites change differently depending on the type of drug used for breast cancer treatment. However, all tested chemotherapeutic treatments resulted in metabolic alteration away from the ‘cholinic phenotype’, which was caused in some cases by decreases in expression of Chkα, GDPD6, and GDPD5 following drug treatment. The choline metabolite concentrations of GPC and/or PC and/or the PC/GPC ratio may serve as non-invasive surrogate makers of therapeutic response in triple-negative breast cancer patients undergoing chemotherapy. Note: This abstract was not presented at the meeting. Citation Format: Menglin Cheng, Zaver M. Bhujwalla, Kristine Glunde. Distinct molecular effects of chemotherapeutic agents on choline phospholipid metabolism of triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2120. doi:10.1158/1538-7445.AM2017-2120

Abstract 5120: Cryptolepine a plant alkaloid, inhibits the growth of nonmelanoma skin cancer cells through inhibition of topoisomerase and induction of DNA damage

Abstract Topoisomerases are highly specialized nuclear enzymes that remove superhelical tension on chromosomal DNA that allows replication and transcription of DNA. Many cancer chemotherapeutic drugs used in the clinics inhibit tumor growth by targeting topoisomerase functions resulting in DNA damage and cancer cell death. Cryptolepine, a major alkaloid isolated from Cryptolepis sanguinolenta plant’s roots, has shown anti-malarial, anti-bacterial, anti-fungal, and anti-inflammatory activities. In the present study, we examined the therapeutic effect of cryptolepine on non-melanoma skin cancer cells (NMSCC), SCC-13 and A431 as an in vitro model, and underlying mechanism of action with special emphasis on topoisomerases and DNA damage check points. Western blot analysis and enzyme activity evaluation assays demonstrated that SCC-13 and A431 cells express comparatively higher levels of topoisomerases and higher enzymatic activities compared with normal human epidermal keratinocytes (NHEK). Topoisomerase expression and activity was greatly reduced after 24 h treatment with 2.5, 5.0 and 7.5 µM cryptolepine. Inhibition of topoisomerases expression and function by cryptolepine resulted in significant DNA damage and enhanced expression of DNA-PK expressions. Cryptolepine induced DNA damage activated DNA damage response proteins as demonstrated by increased phosphorylation of ATM/ATR, BRCA1, Chk1/Chk2 and γH2AX. Consequences of cryptolepine induced DNA damage were also associated with activation of p53 signaling cascade. Cryptolepine induced post-translational modifications such as phosphorylation and acetylation of p53, and inhibition of mdm2 protein expression resulted in activation and accumulation of p53 in SCC-13 and A431 cells. In turn, activated p53 enhanced protein expression of cyclin-dependent kinase inhibitors p16 and p21. Activation of p16 and p21 proteins downregulated expression of cyclin-dependent kinase 2 (CDK2), cyclin A, cyclin D1 and cyclin E and thus induced S-phase cell cycle arrest in NMSC cells with reduced expression of cell division proteins Cdc25a and Cdc25b. Cryptolepine treatment also enhanced release of cytochrome c from mitochondria due to increased disruption of mitochondrial membrane potential. Inhibition of topoisomerase activity and activation of DNA damage response signaling culminated in significantly reduced cell viability and enhanced cell death of SCC-13 and A431 cells. However, NHEK cells were least sensitive to cryptolepine induced cell death. Results of our study strongly suggest for detailed preclinical investigations in animal models to further assess its anti-skin cancer potential and its possible use in human patients. Note: This abstract was not presented at the meeting. Citation Format: Harish C. Pal, Santosh K. Katiyar. Cryptolepine a plant alkaloid, inhibits the growth of nonmelanoma skin cancer cells through inhibition of topoisomerase and induction of DNA damage [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5120. doi:10.1158/1538-7445.AM2017-5120