Extra-mandibular Osteoradionecrosis after the Treatment of Head and Neck Cancer

AIMS

Osteoradionecrosis (ORN) is a serious toxicity of head and neck radiotherapy. It predominantly affects the mandible. Extra-mandibular ORN is rare. The aim of this study was to report the incidence and outcomes of extra-mandibular ORNs from a large institutional database.

MATERIALS AND METHODS

In total, 2303 head and neck cancer patients were treated with radical or adjuvant radiotherapy. Of these, extra-mandibular ORN developed in 13 patients (0.5%).

RESULTS

Maxillary ORNs (n = 8) were a consequence of the treatment of various primaries (oropharynx = 3, sinonasal = 2, maxilla = 2, parotid = 1). The median interval from the end of radiotherapy to the development of ORN was 7.5 months (range 3-42 months). The median radiotherapy dose in the centre of the ORN was 48.5 Gy (range 22-66.5 Gy). Four patients (50%) healed in 7, 14, 20 and 41 months. All temporal bone ORNs (n = 5) developed after treatment to the parotid gland (of a total of 115 patients who received radiotherapy for parotid gland malignancy). The median interval from the end of radiotherapy to the development of ORN was 41 months (range 20-68 months). The median total dose in the centre of the ORN was 63.5 Gy (range 60.2-65.3 Gy). ORN healed in only one patient after 32 months of treatment with repeated debridement and topical betamethasone cream.

CONCLUSION

Extra-mandibular ORN is a rare late toxicity and this current study provides useful information on its incidence and outcome. The risk of temporal bone ORN should be considered in the treatment of parotid malignancies and patients should be counselled. More research is required to determine the optimal management of extra-mandibular ORN, particularly on the role of the PENTOCLO regimen.

Role of Adjuvant Radiotherapy in Acinic Cell Carcinoma of the Salivary Glands: A Systematic Review

A systematic review was carried out to evaluate if adjuvant radiotherapy for acinic cell carcinomas (ACCs) of salivary glands improves survival. Twelve retrospective studies published between 2000 and 2020 that analysed the effect of radiotherapy on salivary gland neoplasms and ACCs of salivary glands and met the inclusion criteria were included in the review. The overall quality of the studies was moderate to low. There was no high-quality evidence for improved survival with radiotherapy for ACCs of the salivary gland. Some evidence suggests that there may be an advantage for patients with high-grade tumours, but these data should be interpreted with caution due to the small number of patients and low-quality evidence. Good quality of evidence is lacking. Recommendation for adjuvant radiotherapy for tumours with poor prognostic factors will require discussion and shared decision-making with the patients.

A Current Review on Analytical Tools for Determination of New Oral Antidiabetic Drugs, Empagliflozin, Linagliptin and Biguanides in Bulk Materials, Pharmaceuticals & Biological Samples

Worldwide the R & D divisions of Pharma industry are actively involved in the development of new therapeutic agents. These agents may be either new entities or partial structural modification of the existing one. The recent FDA statistics represent that the average number of drug filings are increasing every year in the thrust areas like anti-cancer agents, anti-diabetic, antibiotics, cardio-vascular drugs, respiratory drugs etc. Sodium glucose co-transporter-2(SGLT-2) inhibitors, dipeptidyl peptidase-4 (DPP-4) inhibitors and biguanides are effective oral anti-diabetic agents used in treatment of type 2 Diabetes Mellitus. Therefore, the necessity to explore and compare the existing analytical and bioanalytical assays used for determination of such drugs either single or in combination is crucial. Many methods were reported in the literature for the bio-analysis and analysis of four novel gliptins combinations, empagliflozin-linagliptin, empagliflozin-metformin HCl, linagliptin-metformin HCl, empagliflozin-linagliptin-metformin HCl combination with application on Glyxambi®, Synjardy®, Jentadueto®, Trijardy® XR tablets respectively. Furthermore, this review offered an overview of different methods used for determination of every drug alone as empagliflozin from SGLT-2 inhibitors, linagliptin from DPP-4 inhibitors and metformin from biguanides in a tabulated comparative way. Moreover, the current review emphasizes the most common stability indicating assays to be of interest to the analysts in the area of drug control. This review helps in understanding the further need for the development of analytical methods for the estimation of such drugs.

Epitope mapping of the White Spot Syndrome Virus (WSSV) VP28 monoclonal antibody through combined in silico and in vitro analysis reveals the potential antibody binding site

White Spot Syndrome Virus (WSSV) infecting shrimp is an enveloped double-stranded DNA virus. The WSSV is a member of the genus Whispovirus. The envelope protein VP28 is the most investigated protein of WSSV. In the present study, the epitope mapping of the monoclonal antibody (MAb) C-33 was carried out. Based on the epitope mapping results, an antigen-antibody interaction model was derived. Peptide scanning and confirmation of epitopes of MAb C-33 were carried out using the sequence data. The MAb was reactive to the epitope of both recombinant VP28 and the whole virus. The results of the study indicated the presence of an epitope region. The epitope region is found positioned within two peptides, covering 13 amino acids. Framework and CDR (complementarity determining regions) of heavy and light chain (VH & VL) sequences showed identity to germline immunoglobulin sequences. The Web Antibody Modelling (WAM) selected for further evaluation based on a comparative analysis of WAM and Rosetta server-generated models of the Fv region. The docking study using WAM generated model revealed that the residues from LEU98 to GLY105 are active in antibody binding. The findings of this study could form a structural basis for further research in VP28 based diagnostics and therapeutics or vaccine discovery.

Exploration of (hetero)aryl Derived Thienylchalcones for Antiviral and Anticancer Activities

BACKGROUND

Search for new antiviral and anticancer agents are essential because of the emergence of drug resistance in recent years. In continuation of our efforts in identifying the new small molecule antiviral and anticancer agents, we identified chalcones as potent antiviral and anticancer agents.

OBJECTIVE

With the aim of identifying the broad acting antiviral and anticancer agents, we discovered substituted aryl/heteroaryl derived thienyl chalcones as antiviral and anticancer agents.

METHOD

A focused set of thienyl chalcone derivaties II-VI was screened for selected viruses Hepatitis B virus (HBV), Herpes simplex virus 1 (HSV-1), Human cytomegalovirus (HCMV), Dengue virus 2 (DENV2), Influenza A (H1N1) virus, MERS coronavirus, Poliovirus 1 (PV 1), Rift Valley fever (RVF), Tacaribe virus (TCRV), Venezuelan equine encephalitis virus (VEE) and Zika virus (ZIKV) using the National Institute of Allergy and Infectious Diseases (NIAID)'s Division of Microbiology and Infectious Diseases (DMID) antiviral screening program. Additionally, a cyclopropylquinoline derivative IV has been screened for 60 human cancer cell lines using the Development Therapeutics Program (DTP) of NCI.

RESULTS

All thienyl chalcone derivatives II-VI displayed moderate to excellent antiviral activity towards several viruses tested. Compounds V and VI were turned out be active compounds towards human cytomegalovirus for both normal strain (AD169) as well as resistant isolate (GDGr K17). Particularly, cyano derivative V showed very high potency (EC50: <0.05 µM) towards AD169 strain of HCMV compared to standard drug Ganciclovir (EC50: 0.12 µM). Additionally, it showed moderate activity in the secondary assay (AD169; EC50: 2.30 µM). The cyclopropylquinoline derivative IV displayed high potency towards Rift Valley fever virus (RVFV) and Tacaribe virus (TCRV) towards Rift Valley fever virus (RVFV). The cyclopropylquinoline derivative IV is nearly 28 times more potent in our initial in vitro visual assay (EC50: 0.39 µg/ml) and nearly 17 times more potent in neutral red assay (EC50: 0.71 μg/ml) compared to the standard drug Ribavirin (EC50: 11 µg/ml; visual assay and EC50: 12 µg/ml; neutral red assay). It is nearly 12 times more potent in our initial in vitro visual assay (EC50: >1 µg/ml) and nearly 8 times more potent in neutral red assay (EC50: >1.3 µg/ml) compared to the standard drug Ribavirin (EC50: 12 µg/ml; visual assay and EC50: 9.9 µg/ml; neutral red assay) towards Tacaribe virus (TCRV). Additionally, cyclopropylquinoline derivative IV has shown strong growth inhibitory activity towards three major cancers (colon, breast, and leukemia) cell lines and moderate growth inhibition shown towards other cancer cell lines screened.

CONCLUSION

Compounds V and VI were demonstrated viral inhibition towards Human cytomegalovirus, whereas cyclopropylquinoline derivative IV towards Rift Valley fever virus and Tacaribe virus. Additionally, cyclopropylquinoline derivative IV has displayed very good cytotoxicity against colon, breast and leukemia cell lines in vitro.

Serum 25-hydroxyvitamin D levels and incident falls in older women

Three hundred eighty-seven home-dwelling older women were divided into quartiles based on mean serum 25-hydroxyvitamin D (S-25(OH)D) levels. The rates of falls and fallers were about 40% lower in the highest S-25(OH)D quartile compared to the lowest despite no differences in physical functioning, suggesting that S-25(OH)D levels may modulate individual fall risk.

INTRODUCTION

Vitamin D supplementation of 800 IU did not reduce falls in our previous 2-year vitamin D and exercise RCT in 70-80 year old women. Given large individual variation in individual responses, we assessed here effects of S-25(OH)D levels on fall incidence.

METHODS

Irrespective of original group allocation, data from 387 women were explored in quartiles by mean S-25(OH)D levels over 6-24 months; means (SD) were 59.3 (7.2), 74.5 (3.3), 85.7 (3.5), and 105.3 (10.9) nmol/L. Falls were recorded monthly with diaries. Physical functioning and bone density were assessed annually. Negative binomial regression was used to assess incidence rate ratios (IRRs) for falls and Cox-regression to assess hazard ratios (HR) for fallers. Generalized linear models were used to test between-quartile differences in physical functioning and bone density with the lowest quartile as reference.

RESULTS

There were 37% fewer falls in the highest quartile, while the two middle quartiles did not differ from reference. The respective IRRs (95% CI) for falls were 0.63 (0.44 to 0.90), 0.78 (0.55 to 1.10), and 0.87 (0.62 to 1.22), indicating lower falls incidence with increasing mean S-25(OH)D levels. There were 42% fewer fallers (HR 0.58; 040 to 0.83) in the highest quartile compared to reference. Physical functioning did not differ between quartiles.

CONCLUSIONS

Falls and faller rates were about 40% lower in the highest S-25(OH)D quartile despite similar physical functioning in all quartiles. Prevalent S-25(OH)D levels may influence individual fall risk. Individual responses to vitamin D treatment should be considered in falls prevention.

Understanding the structure and reactivity of the C–S linkage in biologically active 5-arylthio-5H-chromenopyridines

Biologically-active 5-arylthio-5H-chromenopyridines were examined to understand their chemical properties.

Identification of Novel 5,6-Dimethoxyindan-1-one Derivatives as Antiviral Agents

BACKGROUND

Discovery of novel antiviral agents is essential because viral infection continues to threaten human life globally. Various heterocyclic small molecules have been developed as antiviral agents. The 5,6-dimethoxyindan-1-on nucleus is of considerable interest as this ring is the key constituent in a range of bioactive compounds, both naturally occurring and synthetic, and often of considerable complexity.

OBJECTIVE

The main purpose of this research was to discover and develop small molecule heterocycles as broad-spectrum of antiviral agents.

METHOD

A focused small set of 5,6-dimethoxyindan-1-one analogs (6-8) along with a thiopene derivative (9) was screened for selected viruses (Vaccinia virus - VACA, Human papillomavirus - HPV, Zika virus - ZIKV, Dengue virus - DENV, Measles virus - MV, Poliovirus 3 - PV, Rift Valley fever virus - RVFV, Tacaribe virus - TCRV, Venezuelan equine encephalitis virus - VEEV, Herpes simplex virus 1 -HSV-1 and Human cytomegalovirus - HCMV) using the National Institute of Allergy and Infectious Diseases (NIAID)'s Division of Microbiology and Infectious Diseases (DMID) antiviral screening program.

RESULTS

These molecules demonstrated moderate to excellent antiviral activity towards variety of viruses. The 5,6-dimethoxyindan-1-one analog (7) demonstrated high efficacy towards vaccinia virus (EC50: <0.05 µM) and was nearly 232 times more potent than the standard drug Cidofovir (EC50: 11.59 µM) in primary assay whereas it demonstrated moderate activity (EC50: >30.00 µM) in secondary plaque reduction assay. The thiophene analog (9) has shown very good viral inhibition towards several viruses such as Human papillomavirus, Measles virus, Rift Valley fever virus, Tacaribe virus and Herpes simplex virus 1.

CONCLUSION

Our research identified a novel 5,6-dimethoxyindan-1-one analog (compound 7), as a potent antiviral agent for vaccinia virus, and heterocyclic chalcone analog (compound 9) as a broad spectrum antiviral agent.

Identification of Novel Bisbenzimidazole Derivatives as Anticancer Vacuolar (H⁺)-ATPase Inhibitors

The vacuolar (H⁺)-ATPases (V-ATPases) are a family of ATP-driven proton pumps and they have been associated with cancer invasion, metastasis, and drug resistance. Despite the clear involvement of V-ATPases in cancer, the therapeutic use of V-ATPase-targeting small molecules has not reached human clinical trials to date. Thus, V-ATPases are emerging as important targets for the identification of potential novel therapeutic agents. We identified a bisbenzimidazole derivative (V) as an initial hit from a similarity search using four known V-ATPase inhibitors (I–IV). Based on the initial hit (V), we designed and synthesized a focused set of novel bisbenzimidazole analogs (2a–e). All newly prepared compounds have been screened for selected human breast cancer (MDA-MB-468, MDA-MB-231, and MCF7) and ovarian cancer (A2780, Cis-A2780, and PA-1) cell lines, along with the normal breast epithelial cell line, MCF10A. The bisbenzimidazole derivative (2e) is active against all cell lines tested. Remarkably, it demonstrated high cytotoxicity against the triple-negative breast cancer (TNBC) cell line, MDA-MB-468 (IC₅₀ = 0.04 ± 0.02 μM). Additionally, it has been shown to inhibit the V-ATPase pump that is mainly responsible for acidification. To the best of our knowledge the bisbenzimidazole pharmacophore has been identified as the first V-ATPase inhibitor in its class. These results strongly suggest that the compound 2e could be further developed as a potential anticancer V-ATPase inhibitor for breast cancer treatment.

Microtubule inhibitor, SP-6-27 inhibits angiogenesis and induces apoptosis in ovarian cancer cells

In ovarian cancer (OVCA), treatment failure due to chemo-resistance is a serious challenge. It is therefore critical to identify new therapies that are effective against resistant tumors and have reduced side effects. We recently identified 4-H-chromenes as tubulin depolymerizing agents that bind to colchicine site of beta-tubulin. Here, we screened a chemical library of substituted 4-H-chromenes and identified SP-6-27 to exhibit most potent anti-proliferative activity towards a panel of human cisplatin sensitive and resistant OVCA cell lines with 50% inhibitory concentration (IC₅₀; mean ± SD) ranging from 0.10 ± 0.01 to 0.84 ± 0.20 μM. SP-6-27 exhibited minimum cytotoxicity to normal ovarian epithelia. A pronounced decrease in microtubule density as well as G2/M cell cycle arrest was observed in SP-6-27 treated cisplatin sensitive/resistant OVCA cells. The molecular mechanism of SP-6-27 induced cell death revealed modulation in cell-cycle regulation by upregulation of growth arrest and DNA damage inducible alpha transcripts (GADD45). An enhanced intrinsic apoptosis was observed in OVCA cells through upregulation of Bax, Apaf-1, caspase-6, -9, and caspase-3. In vitro wound healing assay revealed reduced OVCA cell migration upon SP-6-27 treatment. Additionally, SP-6-27 and cisplatin combinatorial treatment showed enhanced cytotoxicity in chemo-sensitive/resistant OVCA cells. Besides effect on cancer cells, SP-6-27 further restrained angiogenesis by inhibiting capillary tube formation by human umbilical vein endothelial cells (HUVEC). Together, these findings show that the chromene analog SP-6-27 is a novel chemotherapeutic agent that offers important advantages for the treatment of ovarian cancer.

Novel 5-arylthio-5H-chromenopyridines as a new class of anti-fibrotic agents

Liver fibrosis is a critical wound healing response to chronic liver injury such as hepatitis C virus (HCV) infection. If persistent, liver fibrosis can lead to cirrhosis and hepatocellular carcinoma (HCC). The development of new therapies for preventing liver fibrosis and its progression to cancer associated with HCV infection remains a critical challenge. Identification of novel anti-fibrotic compounds will provide opportunities for innovative therapeutic intervention of HCV-mediated liver fibrosis. We designed and synthesized a focused set of 5-arylthio-5H-chromenopyridines as a new class of anti-fibrotic agents. Liver fibrosis assays demonstrated that the compounds 3a and 3c show inhibitory activity towards human hepatic stellate cells (LX2) activation at 10μM. The HCV NS3 and NS5A proteins in HCV subgenome-expressing cells were also significantly reduced in cells treated with 3a and 3c, suggesting the possible inhibitory role of the compounds in HCV translation/replication activities. We have also examined the reactivity of these compounds with medicinally-relevant metal compounds such as platinum and gold. The reactivity of these complexes with metals and during Mass Spectrometry suggests that CS bond cleavage is relatively facile.

Imidazoquinolines: Recent Developments in Anticancer Activity

Cancer remains one of the unsolved diseases of today's advanced drug discovery world even though it is known to humans for centuries. There is continued effort to discover new chemotherapeutic agents to improve the outcome of cancer patients. Small-molecule agonists at tolllike receptor 7 and 8 (TLR7/8) have recently generated renewed interest in cancer research owing to their profound antitumoral activity. TLR-7/8 agonist imidazoquinolines (Imiquimod, and Resiquimod) and dual inhibitor of phosphoinositide 3-kinase and mammalian target of rapamycin (NVP-BEZ235) have emerged as clinically important candidates for treating cancers. This article reviews briefly the synthesis, structure-activity relationship (SAR) and biological activities of clinically studied imidazoquinolines along with novel emerging preclinical imidazoquinolines for the anticancer activity.

Abstract 1231: Novel chromene analogs as small-molecule microtubule destabilizers for the treatment of chemo-resistant ovarian cancer

Ovarian cancer is the most lethal gynecological malignancy with a 5-year survival rate of less than 40%, primarily because of treatment failure due to emergence of chemo-resistance to standard agents. This indicates a dire need for new treatments to improve survival rates. The tubulin dynamics is a promising target for new chemotherapeutic agents. In continuation of our efforts, using medicinal chemistry approach, we recently identified small molecular inhibitors of tubulin polymerization called chromenes, as new ovarian anti-cancer agents. A set of chromene compounds were screened for anti-cancer effect on cisplatin sensitive (A2780, SKOV-3, TOV112D) and cisplatin resistant (OVCAR-3, A2780-cisR, TOV112D-cisR) ovarian cancer cells. In vitro cell viability was assessed by fluorescence based Alamar Blue assay. Our preliminary studies identified SP-6-27 (IC50 range: 0.102± 0.006 - 2.24±0.056 μM) and SP-6-37 (IC50 range: 0.258± 0.159 - 3.61±0.049 μM) as most potent chromene analogs. Both compounds exhibited a potent anticancer activity towards both cisplatin sensitive (SP-6-27 IC50: 0.14± 0.03 μM; SP-6-37 IC50: 1.35± 0.88 μM) and cisplatin resistant (SP-6-27 IC50: 0.81± 1.2 μM; SP-6-37 IC50: 2.09± 1.7 μM) cell lines. The compounds exhibited least cytotoxicity towards normal ovarian epithelial cells (SP-6-27- IC50: 83.35 ± 9.47 μM; SP-6-37- IC50: 75.77 ± 5.37 μM). Additionally, the analysis of apoptotic changes as determined by Annexin-V assay revealed an enhanced apoptosis in both cisplatin sensitive and resistant cells upon treatment with compounds SP-6-27 or SP-6-37. Together, the data demonstrates that ovarian cancer cell lines respond sensitively to SP-6-27 and SP-6-37, demonstrating that the chromene scaffold is effective in suppressing ovarian cancer cell growth. The findings indicate that the novel chromene analogs are a new class of chemotherapeutic agents that will offer advantages for the treatment of ovarian cancer.

Citation Format: Arpita Kulshrestha, Safaa A. Ibrahim, Gajendra K. Katara, Renukadevi Patil, Shivaputra Patil, Kenneth D. Beaman. Novel chromene analogs as small-molecule microtubule destabilizers for the treatment of chemo-resistant ovarian cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1231.

Novel Inhibitory Effect of a Lysophosphatidic Acid 2 Agonist on Allergen-Driven Airway Inflammation

Lysophosphatidic acid (LPA) is a pleiotropic lipid signaling molecule associated with asthma pathobiology. LPA elicits its effects by binding to at least six known cell surface G protein-coupled receptors (LPA1-6) that are expressed in the lung in a cell type-specific manner. LPA2 in particular has emerged as an attractive therapeutic target in asthma because it appears to transduce inhibitory or cell-protective signals. We studied a novel and specific small molecule LPA2 agonist (2-[4-(1,3-dioxo-1H,3H-benzoisoquinolin-2-yl)butylsulfamoyl] benzoic acid [DBIBB]) in a mouse model of house dust mite-induced allergic airway inflammation. Mice injected with DBIBB developed significantly less airway and lung inflammation compared with vehicle-treated controls. Levels of lung Th2 cytokines were also significantly attenuated by DBIBB. We conclude that pharmacologic activation of LPA2 attenuates Th2-driven allergic airway inflammation in a mouse model of asthma. Targeting LPA receptor signaling holds therapeutic promise in allergic asthma.

Annexin A5 levels or circulating microparticles: what we see depends mainly on what we look for

Click here to view the article Letter to the Editor by C. Reutelingsperger et al.

Cost-effectiveness of vitamin D supplementation and exercise in preventing injurious falls among older home-dwelling women: findings from an RCT

This study assessed the cost-effectiveness of vitamin D supplementation and exercise, separately and combined, in preventing medically attended injurious falls among older home-dwelling Finnish women. Given a willingness to pay of €3,000 per injurious fall prevented, the exercise intervention had an 86 % probability of being cost-effective in this population.

INTRODUCTION

The costs of falling in older persons are high, both to the individual and to society. Both vitamin D and exercise have been suggested to reduce the risk of falls. This study assessed the cost-effectiveness of vitamin D supplementation and exercise, separately and combined, in preventing medically attended injurious falls among older Finnish women.

METHODS

Economic evaluation was based on the results of a previously published 2-year randomized controlled trial (RCT) where 409 community-dwelling women aged 70 to 80 years were recruited into four groups: (1) no exercise + placebo (D-Ex-), (2) no exercise + vitamin D 800 IU/day (D+Ex-), (3) exercise + placebo (D-Ex+), and (4) exercise + vitamin D 800 IU/day (D+Ex+). The outcomes were medically attended injurious falls and fall-related health care utilization costs over the intervention period, the latter evaluated from a societal perspective based on 2011 unit costs. Incremental cost-effectiveness ratios (ICER) were calculated for the number of injurious falls per person-year prevented and uncertainty estimated using bootstrapping.

RESULTS

Incidence rate ratios (95 % CI) for medically attended injurious falls were lower in both Ex+ groups compared with D-Ex-: 0.46 (0.22 to 0.95) for D-Ex+, 0.38 (0.17 to 0.81) for D+Ex+. Step-wise calculation of ICERs resulted in exclusion of D+Ex- as more expensive and less effective. Recalculated ICERs were €221 for D-Ex-, €708 for D-Ex+, and €3,820 for D+Ex+; bootstrapping indicated 93 % probability that each injurious fall avoided by D-Ex+ per person year costs €708. At a willingness to pay €3,000 per injurious fall prevented, there was an 85.6 % chance of the exercise intervention being cost-effective in this population.

CONCLUSIONS

Exercise was effective in reducing fall-related injuries among community-dwelling older women at a moderate cost. Vitamin D supplementation had marginal additional benefit. The results provide a firm basis for initiating feasible and cost-effective exercise interventions in this population.

Dental notation for primary teeth: a review and suggestion of a novel system

BACKGROUND

Tooth designation systems are routinely used in dental practice, for identification of teeth, recording dental data and communication among dental professionals. There are various dental notations systems for the primary and permanent dentition. The most popular are the Zsigmondy-Palmer system, the Universal Numbering System, and the FDI system. Others includes the Victor Haderup system, the Woelfel system, and the MICAP system. The majority of dental notations are focused on permanent teeth and are modified for primary teeth, even though the latter erupt before the permanent dentition.

CONCLUSION

Advantages and disadvantages of notations for primary dentition are discussed and compared to a new alphanumeric system for primary teeth which is considered simple and convenient.

Combined mitigation of the gastrointestinal and hematopoietic acute radiation syndromes by an LPA2 receptor-specific nonlipid agonist

Pharmacological mitigation of injuries caused by high-dose ionizing radiation is an unsolved medical problem. A specific nonlipid agonist of the type 2 G protein coupled receptor for lysophosphatidic acid (LPA2) 2-[4-(1,3-dioxo-1H,3H-benzoisoquinolin-2-yl)butylsulfamoyl]benzoic acid (DBIBB) when administered with a postirradiation delay of up to 72 hr reduced mortality of C57BL/6 mice but not LPA2 knockout mice. DBIBB mitigated the gastrointestinal radiation syndrome, increased intestinal crypt survival and enterocyte proliferation, and reduced apoptosis. DBIBB enhanced DNA repair by augmenting the resolution of γ-H2AX foci, increased clonogenic survival of irradiated IEC-6 cells, attenuated the radiation-induced death of human CD34(+) hematopoietic progenitors and enhanced the survival of the granulocyte/macrophage lineage. DBIBB also increased the survival of mice suffering from the hematopoietic acute radiation syndrome after total-body irradiation. DBIBB represents a drug candidate capable of mitigating acute radiation syndrome caused by high-dose γ-radiation to the hematopoietic and gastrointestinal system.

Abstract B28: Autotaxin, LPA1 and LPA5 receptors in the tumor microenvironment determine melanoma invasion and metastasis

Autotaxin (ATX), a lysophospholipase D that generates the growth factor-like mediator lysophosphatidic acid LPA, is up-regulated in metastatic and chemotherapy-resistant carcinomas. Many cancer cells secrete ATX, and it contributes to their invasive properties. The biological functions of ATX are mediated by LPA acting on G protein-coupled receptors (LPAR1-8). Many cancers overexpress multiple subtypes of LPAR and the overexpression of LPAR leads to malignant transformation, metastasis, and resistance to therapy. We have previously shown that knockdown of ATX expression in B16F10 melanoma cells decreased tumor invasion in vitro and lung metastasis in vivo. In our present study, we sought to understand the roles of LPAR both in the tumor cells and stromal cells of the tumor microenvironment.

B16F10 melanoma cells predominantly express the LPA5 receptor. We found that these cells do not invade across a matrigel layer in response to LPA. shRNA knockdown of LPA5 receptors in B16F10 attenuates this inhibition, suggesting that the LPA5 receptor acts as an anti-invasive receptor in these tumor cells. Interestingly, we identified a different role for host LPA5 receptor. We found that the incidence of B16F10 lung metastasis was significantly reduced in the LPA5 knockout mice compared to wild type mice. In addition, LPA1 knockout mice also showed diminished B16F10 lung metastasis suggesting that host LPA1 and LPA5 receptors play critical roles in the seeding of metastasis. The decrease in tumor cell residence in the lungs of these knockout animals was apparent at 24 hours after injection. However, deletion of LPA1 or LPA5 did not affect the subcutaneous growth of B16F10 tumors.

In summary, our results suggest that LPAR, in particular LPA5 and LPA1 receptors in tumor and stromal cells may play different roles in invasion and the seeding of metastasis.

Citation Format: Sue-Chin Lee, Yuko Fujiwara, Jianxiong Liu, Junming Yue, Ryoko Tsukahara, Erzsebet Szabo, Renukadevi Patil, Duane D. Miller, Louisa Balazs, Tamas Oravecz, Gabor J. Tigyi. Autotaxin, LPA1 and LPA5 receptors in the tumor microenvironment determine melanoma invasion and metastasis. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B28. doi:10.1158/1538-7445.CHTME14-B28

Autotaxin and LPA1 and LPA5 receptors exert disparate functions in tumor cells versus the host tissue microenvironment in melanoma invasion and metastasis

Autotaxin (ENPP2/ATX) and lysophosphatidic acid (LPA) receptors represent two key players in regulating cancer progression. The present study sought to understand the mechanistic role of LPA G protein-coupled receptors (GPCR), not only in the tumor cells but also in stromal cells of the tumor microenvironment. B16F10 melanoma cells predominantly express LPA5 and LPA2 receptors but lack LPA1. LPA dose dependently inhibited invasion of cells across a Matrigel layer. RNAi-mediated knockdown of LPA5 relieved the inhibitory effect of LPA on invasion without affecting basal invasion. This suggests that LPA5 exerts an anti-invasive action in melanoma cells in response to LPA. In addition, both siRNA-mediated knockdown and pharmacologic inhibition of LPA2 reduced the basal rate invasion. Unexpectedly, when probing the role of this GPCR in host tissues, it was found that the incidence of melanoma-derived lung metastasis was greatly reduced in LPA5 knockout (KO) mice compared with wild-type (WT) mice. LPA1-KO but not LPA2-KO mice also showed diminished melanoma-derived lung metastasis, suggesting that host LPA1 and LPA5 receptors play critical roles in the seeding of metastasis. The decrease in tumor cell residence in the lungs of LPA1-KO and LPA5-KO animals was apparent 24 hours after injection. However, KO of LPA1, LPA2, or LPA5 did not affect the subcutaneous growth of melanoma tumors.

IMPLICATIONS

These findings suggest that tumor and stromal LPA receptors, in particular LPA1 and LPA5, play different roles in invasion and the seeding of metastasis.

Design and synthesis of sulfamoyl benzoic acid analogues with subnanomolar agonist activity specific to the LPA2 receptor

Lysophosphatidic acid (LPA) is a growth factor-like mediator and a ligand for multiple GPCR. The LPA₂ GPCR mediates antiapoptotic and mucosal barrier-protective effects in the gut. We synthesized sulfamoyl benzoic acid (SBA) analogues that are the first specific agonists of LPA₂, some with subnanomolar activity. We developed an experimental SAR that is supported and rationalized by computational docking analysis of the SBA compounds into the LPA₂ ligand-binding pocket.