New Development of Novel Berberine Derivatives against Bacteria.

Many berberine derivatives have been synthesized for their antibacterial activity in the past years. In order to elucidate their new Structural Activity Relationship (SAR), the recently synthesized berberine derivatives are reviewed. The newly synthesized berberine derivatives are reported in this review with novel modifications on the berberine structure at various positions. It is hoped that this article would help scientists to design and synthesize new berberine derivatives with high potency and a broad spectrum of antimicrobial activities, more effectiveness and lower toxicity for improved antimicrobial therapy. These berberine derivatives could be developed as novel antibacterial agents to treat patients with infectious diseases, especially caused by resistant bacteria.

Gamma-H2AX - a novel biomarker for DNA double-strand breaks.

When DNA damage, whether it is endogenous or exogenous, forms double stranded breaks (DSBs), it is always followed by the phosphorylation of the histone, H2AX. H2AX is a variant of the H2A protein family, which is a component of the histone octomer in nucleosomes. It is phosphorylated by kinases such as ataxia telangiectasia mutated (ATM) and ATM-Rad3-related (ATR) in the PI3K pathway. This newly phosphorylated protein, gamma-H2AX, is the first step in recruiting and localizing DNA repair proteins. DSBs can be induced by mechanisms such as ionizing radiation or cytotoxic agents and subsequently, gamma-H2AX foci quickly form. These foci represent the DSBs in a 1:1 manner and can be used as a biomarker for damage. An antibody can be raised against gamma-H2AX which can therefore be visualized by immunofluorescence through secondary antibodies. The detection and visualization of gamma-H2AX by flow cytometry allow the assessment of DNA damage, related DNA damage proteins and DNA repair. Gamma-H2AX also has other applications in the detection of genomic damage caused by cytotoxic chemical agents and environmental and physical damage, especially in the context of cancer treatment and therapy.

A novel camptothecin analog with enhanced antitumor activity.

BACKGROUND: The use of camptothecin (CPT) derivatives is limited by severe toxicity associated with the instability of their chemical structure. We have developed a stable CPT derivative (CPT417) and have investigated its biological activity in comparison to the currently used CPT analogs. MATERIALS AND METHODS: The anticancer effects of CPT417 were assessed in vitro, with glioblastoma and colon cancer cell lines, and in vivo with mice bearing mammary adenocarcinoma tumors implanted subcutaneously in the flank. Cytotoxicity was assessed using vital dye exclusion, timelapse microscopy and colony formation. RESULTS: CPT417 and topotecan inhibited glioblastoma cell growth at comparable levels and both compounds inhibited clonogenicity of colon cancer cells more effectively than irinotecan. CPT417 showed a much greater inhibition of mammary tumor growth compared to topotecan, both by intraperitoneal and oral administration. CONCLUSION: CPT417 shows dramatically reduced toxicity and an enhanced antitumor activity compared to topotecan.

New molecular mechanisms of action of camptothecin-type drugs.

Camptothecin (CPT) derivatives have emerged as a promising group of chemotherapeutic agents. The FDA has approved the CPT derivatives topotecan and irinotecan for second line treatment of ovarian cancer and metastatic colorectal cancer, respectively. These and other CPT derivatives have become part of the multi-million dollar industry that is dedicated to finding better chemotherapeutic agents with excellent tumor kill and less normal tissue toxicity. In order to reach this goal it is imperative to understand the details of the mechanisms of action and the targets of these drugs, as well as the cellular response to the drugs. Although investigations of CPT date back to the 1960's, most of the studies that have been added to our present knowledge were done in the last 10 years. The purpose of this paper is to review the latest insights into the CPT binding site, CPT-induced gene expression and CPT-induced pathways to apoptosis.

Selective Toxicity of a Highly Potent Camptothecin Analogue: A Pilot Study with Glioblastoma Multiforme Cells.

BACKGROUND/AIM: We developed a novel camptothecin analogue, CPT417, that yields reduced toxicity compared to other analogues used in chemotherapeutic regimens. In this pilot study, we assessed the activity of CPT417 against glioblastoma multiforme (GBM) cells and glioma stem cells. MATERIALS AND METHODS: The human U251 GBM cell line and normal human astrocytes were cultured in parallel for clonogenic survival analysis following exposure to increasing concentrations of CPT417. Cell viability of a glioma stem cell line was assessed 5 days after exposure to a range of CPT417 concentrations. RESULTS: CPT417 completely inhibited clonogenic survival of GBM cells at 10 nM, whereas this concentration only inhibited astrocytes by approximately 50%. Cell viability analysis of glioma stem cell cultures yielded a half-maximal response at 15 nM. CONCLUSION: CPT417 acts selectively against GBM cells at concentrations that are at least an order of magnitude below reported values for related alkylating agents in clinical use.

Synthesis and pharmacology of new camptothecin drugs.

Camptothecin (CPT) drugs exhibit antineoplastic activity against colorectal, breast, lung and ovarian cancers. This review briefly summarizes the pharmacology of CPT drugs, examines four strategies and methods for the synthesis of camptothecins, and finally discusses homocamptothecins and silatecans, two new classes of CPT analog.

Centrosome impairments and consequent cytokinesis defects are possible mechanisms of taxane drugs.

Taxol and taxotere are two of the most promising anticancer drugs. To determine the mechanisms responsible for cell death after exposure to low doses of taxane, PC3 cells were treated with taxol and taxotere, and observed with immunofluoroscence microscopy. Pericentriolar material dissociation and blockage of normal centrosome separation were found to result in two different abnormal spindle types; multipolar and monopolar spindles, respectively. The majority of abnormal spindles induced by taxol were monopolar spindles, whereas taxotere mostly induced abnormal multipolar spindles. Consequently, monopolar spindle mitosis resulted in cleavage failure, while multipolar spindle mitosis led to the formation of both cleavage failure and multipolar cell division. Multinucleation characterized interphase cells which had undergone cytokinesis defects. These cells subsequently became giant multinucleated cells after several rounds of cell cycle with sustained cleavage failure, and were gradually eliminated through cell death.

Novel camptothecin derivatives.

Efforts continue to be made in the field of oncology to find new and effective chemotherapeutic agents against cancer. From these efforts the camptothecins have emerged as a promising group of agents. Camptothecin, first discovered in 1958, was found to be an effective anti-chemotherapeutic agent, but the toxicities were too great to be used in a clinical setting. Derivatives of the original camptothecin molecule have been created by modifying one or more rings in an effort to improve the pharmacokinetics and toxicity profiles of the parent compound. This article reviews both the in vivo and in vitro characteristics of these novel agents.

Recent developments in radiosensitization.

Radiation therapy is essential for local tumor control for many types of cancer histologies. Technological advancements in recent years have allowed for precise irradiation of target tissues while minimizing the dose to non-target tissues. To enhance radiation damage to cancer cells and further limit the radiation effects on normal tissue, researchers have explored compounds that specifically target cancer cells and make them more sensitive to ionizing radiation. Recent radiosensitization research has focused on promising compounds that alter hypoxia, inhibit topoisomerases, interfere with microtubules, and activate caspases, among other mechanisms. Many such compounds have shown impressive results in pre-clinical trials against a variety of cell types, but their safety, efficacy and practicability in clinical trials remains to be demonstrated. This review seeks to provide an overview of recent research in radiosensitization, detailing some of the more successful compounds, and illustrating avenues for future research.

Radiation-associated Cardiac Injury.

Chest radiotherapy continues to play an important role in the treatment of breast cancer, Hodgkin's lymphoma, and other malignancies. Subsequent cardiac injury has been described involving essentially all structures of the heart, with most radiation-induced injury being progressive in nature. Our understanding over the multifactorial etiology and development of radiation-associated cardiac injury has advanced, leading to improved techniques aimed at decreasing cardiac radiation exposure and associated risks. Monitoring after radiotherapy clearly appears to be indicated; however, optimal recommendations regarding cardiac screening remain difficult to establish.

A Novel Microtubule-Disrupting Agent Induces Endoplasmic Reticular Stress-Mediated Cell Death in Human Hepatocellular Carcinoma Cells.

Here, we present evidence of a novel microtubule-disrupting agent, N-deacetyl-N-(chromone-2-carbonyl)-thiocolchicine (TCD), exhibiting potent antitumor activity (with IC50 values in the nanomolar range) against hepatocellular carcinoma cell lines. Cell cycle analysis revealed that TCD induced G2/M cell-cycle arrest in a dose- and time-dependent manner in both Hep-J5 and Mahlavu HCC cell lines. TCD also induced a decrease in mitochondrial membrane potential (ΔΨm) and caused DNA damage. Mechanistically, TCD activated protein kinase RNA-like endoplasmic reticular kinase and several transcription factors, including activating transcription factor (ATF) 6, ATF4, ATF3, and the CCAAT-enhancer binding protein homologous protein. These data clearly demonstrate that the antitumor activity of TCD is mechanistically linked to its capacity to trigger both intrinsic and extrinsic apoptotic cell death via endoplasmic reticular stress pathway. The potent antitumor activity of TCD was similarly demonstrated in a hepatocellular carcinoma xenograft model, where 5 and 10 mg/kg doses of TCD significantly arrested Hep-J5 and Mahlavu tumor growth. Our finding suggests that TCD is a promising therapeutic agent against hepatocellular carcinoma; further translational assessment of its clinical usage is warranted.

Study of the G2/M cell cycle checkpoint in irradiated mammary epithelial cells overexpressing Cul-4A gene.

PURPOSE: Members of the cullin gene family are known to be involved in cell cycle control. One of the cullin genes, Cul-4A, is amplified and overexpressed in breast cancer cells. This study investigates the effect of Cul-4A overexpression upon G2/M cell cycle checkpoint after DNA damage induced by either ionizing or nonionizing radiation. METHODS AND MATERIALS: The normal mammary epithelial cell line MCF10A was stably transfected with full-length Cul-4A cDNA. Independent clones of MCF10A cells that overexpress Cul-4A proteins were selected and treated with either 8 Gy of ionizing radiation or 7 J/M(2) of UV radiation. The profile of cell cycle progression and the accumulation of several cell cycle proteins were analyzed. RESULTS: We found that overexpression of Cul-4A in MCF10A cells abrogated the G2/M cell cycle checkpoint in response to DNA damage induced by ionizing irradiation, but not to DNA damage induced by nonionizing radiation. Analysis of cell cycle proteins showed that after ionizing irradiation, p53 accumulated in the mock-transfected MCF10A cells, but not in the Cul-4A transfectants. CONCLUSION: Our results suggest a role for Cul-4A in tumorigenesis and/or tumor progression, possibly through disruption of cell cycle control.

Centrosomes--their role in tumors and cancer therapy.

The centrosome is a small organelle located near the nucleus which acts as the microtubule organizing center for the cell. Abnormalities in centrosome replication resulting in centrosome amplification have been identified in most of the common human cancers and implicated in the development of genetic instability and cancer. Research in centrosomes is evolving rapidly with identification of key regulatory proteins. This knowledge could help to explain the mechanisms of action of existing cancer treatments and also lead to the development of new molecularly-targeted therapy.

Anticancer effects and mechanisms of polysaccharide-K (PSK): implications of cancer immunotherapy.

Polysaccharide-K (polysaccharide-Kureha; PSK), also known as krestin, is a unique protein-bound polysaccharide, which has been used as a chemoimmunotherapy agent in the treatment of cancer in Asia for over 30 years. PSK and Polysaccharopeptide (PSP) are both protein-bound polysaccharides which are derived from the CM-101 and COV-1 strains of the fungus Coriolus versicolor by Japanese and Chinese researchers, respectively. Both polysaccharide preparations have documented anticancer activity in vitro, in vivo and in human clinical trials, though PSK has been researched longer and has therefore undergone more thorough laboratory, animal and clinical testing. Several randomized clinical trials have demonstrated that PSK has great potential as an adjuvant cancer therapy agent, with positive results seen in the adjuvant treatment of gastric, esophageal, colorectal, breast and lung cancers. These studies have suggested the efficacy of PSK as an immunotherapy or biological response modifier (BRM). BRMs potentially have the ability to improve the "host versus tumor response," thereby increasing the ability of the host to defend itself from tumor progression. The mechanisms of biological response modification by PSK have yet to be clearly and completely elucidated. Some studies suggest that PSK may act to increase leukocyte activation and response through up-regulation of key cytokines. Indeed, natural killer (NK) and lymphocyte-activated killer (LAK) cell activation has been demonstrated in vivo and in vitro, and recent genetic studies reveal increased expression of key immune cytokines in response to treatment with PSK. An antimetastatic action of PSK has also been demonstrated and is perhaps attributed to its potential to inhibit metalloproteinases and other enzymes involved in metastatic activity. PSK has also been shown to cause differentiation of leukemic cells in vitro, and this effect has been attributed to induction of differentiation cytokines. PSK has further been shown to have antioxidant capacity which may allow it to play a role as a normal tissue chemo- and radio-protector when used in combination with adjuvant or definitive chemotherapy and/or radiotherapy in the treatment of cancer, while it may also enable it to defend the host from oxidative stress. Interestingly, studies have also shown that PSK may actually inhibit carcinogenesis by inhibiting the action of various carcinogens on vulnerable cell lines. This action of PSK may play a role in preventing second primary tumors when an inducing agent, such as tobacco or asbestos, is suspected and may also prevent second malignancies due to the carcinogenic effects of radiotherapy and cytotoxic chemotherapy. Another very important aspect of chemoimmunotherapy, in general is that it may be used on debilitated patients such as those with AIDS and the elderly who might otherwise be denied potentially helpful adjuvant cytotoxic chemotherapy. Further determination of the mechanisms of these anti-cancer, immunostimulating and biological response modifying effects of PSK as well as of other protein-bound polysaccharides is certainly warranted. Indeed, with modern cellular and molecular biology techniques, a better understanding of the specific molecular effects of PSK on tumor cells as well as leukocytes may be determined. Much of the research that has been done on PSK is outlined in this paper and may serve as a foundation toward determining the mechanisms of action of this and other protein-bound polysaccharides in the treatment of cancer. This information may open new doors in the development of novel strategies for the treatment of malignancies using adjuvant immunotherapy in combination with surgery, chemotherapy and/or radiotherapy.

Enhanced apoptotic effects of novel paclitaxel analogs on NCI/ADR-RES breast cancer cells.

This study aimed to investigate the apoptotic effects of novel paclitaxel analogs on NCI/ADR-RES breast cancer cells. Using the colony formation assay, the cytotoxicity of three novel paclitaxel analogs were evaluated on NCI/ADR-RES cells which overexpress multidrug-resistant gene (MDR1). All three novel paclitaxel analogs exhibited significantly higher cytotoxicity on NCI/ADR-RES cells than paclitaxel. One analog, TL139, was 140 times more effective than paclitaxel. Using TUNEL and DNA fragmentation assay, remarkably increased apoptosis in the paclitaxel analog-treated cells was observed at 48-72 hours, but not in paclitaxel-treated cells. Caspases-3/7 were dramatically activated at 48-72 hours by the novel paclitaxel analogs. The enhanced activity of caspases-3/7 was evidently verified by the measurement of the cleavage of poly(ADP-ribose) polymerase (PARP). The increased activity of caspases-3/7 significantly correlated with the enhanced apoptosis and cell survival data. Treatment with paclitaxel analogs resulted in a significant amount of mitotic arrest. Using Western blot, the phosphorylation of Bcl-2 protein was found in palictaxel analog-treated cells in a time-dependent manner similar to that of mitotic arrest, thereby indicating that there existed a close correlation between Bcl-2 phosphorylation and mitotic arrest that preceded apoptosis. We conclude that novel taxane analogs could effectively kill MDR1-positive breast cancer cells via the mode of apoptosis.

Radioprotectants to reduce the risk of radiation-induced carcinogenesis.

PURPOSE: Development of radioprotective agents has focused primarily on cytoprotection from relatively high doses of therapeutic radiation and nuclear disasters. Epidemiological studies and radiobiological models report the potential for stochastic effects from relatively low-dose radiation exposure. Diagnostic studies like computed tomography (CT) expose the patient to a small but significant amount of radiation, which has been reported to increase the risk for carcinogenesis. Young patients expected to undergo multiple CT studies may benefit from a protective agent given prior to CT. This review includes published data of agents that have been shown to protect against radiation-induced carcinogenesis. A discussion follows regarding the data that describes the extent of radiation exposure during CT, as well as technical modifications, which also reduce radiation exposure. RESULTS/CONCLUSIONS: Most experiments have used in vivo animal models or in vitro cell lines. Ethical barriers prevent large-scale human studies, although, there are two prospective human studies from the Chernobyl nuclear accident. Collectively, all of these studies provide evidence of statistically significant reductions in radiation-induced carcinogenesis. Protection is achieved by several mechanisms, which include free radical scavenging, caloric restriction, non-steroidal anti-inflammatory agents, humoral factors, and an oxidative agent. Enhanced efficacy is achieved when targeting multiple mechanisms. The data presented provides the scientific foundation for future development of a radioprotectant that may reduce the risk of carcinogenesis from low-dose exposure when certain at-risk populations undergo diagnostic studies like CT.

Cardiotoxicity of molecular-targeted drug therapy.

Cardiotoxicity is a well-known side-effect described in patients receiving various antineoplastic agents. With the abundance of clinical research and a heavy focus on drug development over the past decade, there has been a major shift in the use of non-specific cytotoxic drugs to molecular-targeted drug therapy. However, as a result, it has become clear that these drugs have numerous adverse effects, both on-target and off-target. Small-molecule tyrosine kinase inhibitors and other molecular-targeted agents, including monoclonal antibodies, have been the primary agents associated with cardiotoxicity. As more molecular-targeted therapies are developed, early recognition and management of drug-related cardiotoxicity will be extremely important in order to reduce morbidity and mortality. Pre-treatment evaluation with a surface electrocardiogram, echocardiography, cardiac history, and comprehensive review of concomitant medications are the current mainstay of treatment. However, much is still unknown about the potential cardiotoxic side-effects of these drug and optimal management. In the present article, we aim to review the cardiovascular implications and related cardiotoxicities associated with molecular target-based chemotherapeutic agents, with special emphasis on hypertension, cardiac dysfunction, and QT prolongation. Their implication, mechanism, and management are discussed where possible.

Current status in chemotherapy for advanced pancreatic adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal types of cancer in the United States. Surgical resection remains the only curative treatment, but fewer than 20% of patients qualify as candidates. The past two decades saw major changes in the treatment of advanced PDA, a shift of standard protocol from 5-fluorouracil to gemcitabine and gemcitabine-based combinations, the introduction of molecular target therapy and multi-agent regimens. However, even with advancements in medicine, PDA is still extremely resistant to currently available regimens, which results in poor prognosis, with only 5.2% of patients alive at three years. This provides a challenge to scientists as they seek to find the best active regimen with the least side-effects. In this article, we review the current recommended guidelines from the National Comprehensive Cancer Network. In addition, we highlight major clinical trials since 2011.

Brentuximab vedotin: first-line agent for advanced Hodgkin lymphoma.

Hodgkin lymphoma (HL) is characterized by malignant Reed-Sternberg cells which express CD30. Current National Comprehensive Cancer Network guidelines for patients with advanced HL (stage III/IV disease) recommend adriamycin, bleomycin, vinblastine, and dacarbazine (ABVD), or escalated bleomycin, etoposide, adriamycin, cyclophosphamide, vincristine, procarbazine, and prednisone (BEACOPP) as first-line regimens. ABVD appears to be as effective, with fewer side effects, as escalated BEACOPP. Escalated BEACOPP leads to a greater progression-free survival but no difference in overall survival. Recent advancements in technology have enabled an exciting shift to molecular-targeted cancer therapy. Brentuximab vedotin, a CD30-directed antibody conjugate, specifically targets malignant HL cells. It is approved by the Food and Drug Administration for the treatment of systemic anaplastic large-cell lymphoma and refractory HL that has progressed after autologous stem cell transplant, or after two prior multiagent chemotherapy regimens among patients ineligible to receive a transplant.

Improved radiotherapy for primary and secondary liver cancer: stereotactic body radiation therapy.

BACKGROUND: Radiation therapy for primary and secondary liver cancer has been limited due to dose-limiting radiation-associated liver injury. Stereotactic body radiation therapy (SBRT) permits higher dose to tumors while minimizing radiation to uninvolved liver. The purpose of this study was to assess the efficacy and safety of SBRT for treating primary and secondary hepatic neoplasms. MATERIALS AND METHODS: We performed a systematic review of prospective clinical trials published in English. RESULTS: Fifteen studies involving 158 patients with primary tumors and 341 patients with metastases to the liver were included. Treatment was performed in 1-10 fractions to total doses of 18-60 Gy. One year local control and overall survival rates were 50-100% and 33-100% respectively. There were 13 cases of radiation-induced liver disease and 4 grade 5, 6 grade 4, and 69 grade 3 adverse events reported. CONCLUSION: For patients who are unable or unwilling to undergo local therapy, SBRT is safe and efficacious for treating primary and secondary liver cancer.