Canonical and non-canonical integrin-based adhesions dynamically interconvert

Adhesions are critical for anchoring cells in their environment, as signaling platforms and for cell migration. In line with these diverse functions different types of cell-matrix adhesions have been described. Best-studied are the canonical integrin-based focal adhesions. In addition, non-canonical integrin adhesions lacking focal adhesion proteins have been discovered. These include reticular adhesions also known as clathrin plaques or flat clathrin lattices, that are enriched in clathrin and other endocytic proteins, as well as extensive adhesion networks and retraction fibers. How these different adhesion types that share a common integrin backbone are related and whether they can interconvert is unknown. Here, we identify the protein stonin1 as a marker for non-canonical αVβ5 integrin-based adhesions and demonstrate by live cell imaging that canonical and non-canonical adhesions can reciprocally interconvert by the selective exchange of components on a stable αVβ5 integrin scaffold. Hence, non-canonical adhesions can serve as points of origin for the generation of canonical focal adhesions.

The Impact of Co-Alterations on Outcomes after Local Therapy for Patients with KRAS-Mutant Lung Adenocarcinoma Brain Metastases

PURPOSE/OBJECTIVE(S)

Brain metastases are common in NSCLC with up to 25% of patients having brain metastases (BMs) at the time of diagnosis and 30% developing BMs during their disease course. KRAS is an oncogenic driver in approximately 25% of lung adenocarcinomas. Genomic alterations co-occurring with KRAS are associated with distinct biological landscapes which may influence prognosis. Herein, we sought to identify correlations between genomic profiles, intracranial progression free survival (iPFS), and overall survival (OS).

MATERIALS/METHODS

We retrospectively reviewed 156 patients with KRAS-mutant lung adenocarcinoma BM who underwent SRS for their BMs at MSKCC from 2010-2022. Each patient had at least one tumor sample profiled with MSK-IMPACT, a custom FDA-cleared next-generation sequencing. Mutations, copy number alterations, and fusions were filtered for driver alterations using OncoKB. Survival outcomes were calculated from date of MRI indicating metastatic brain disease.

RESULTS

Of the 156 patients, 80 patients presented with BMs at diagnosis whereas 76 developed BMs during their disease course, with a median 2 lines of therapy prior to BM diagnosis. The most common KRAS mutation was G12C (n = 64; 41%), G12V (n = 26, 17%), G12D (n = 17; 11%), and G12A (n = 11; 7%). The most frequently co-altered genes were TP53 (n = 71, 46%), STK11 (n = 51, 33%), CDKN2A (n = 27, 17%), KEAP1 (n = 17, 11%), and SMARCA4 (n = 10, 6%). The presence of a KEAP1 co-occurring alteration was associated with inferior iPFS (HR 1.95, 95% CI 1.05 - 3.59, p = 0.035) and the presence of SMARCA4 was also associated with inferior iPFS (HR 2.28, 95% CI 1.05 - 4.95, p = 0.038). The presence of an STK11 mutation was associated with worse OS (HR 1.57, 95% 1.01 - 2.43, p = 0.045). In a multi-variate clinico-genomic model, KEAP1 and STK11 co-occurring alterations remained significantly associated with iPFS. Patients with KEAP1-altered tumors had an increased incidence of intracranial regional progression. The 24-month cumulative incidence of regional progression amongst KEAP1-altered tumors was 57% (95% CI, 29%-77%) compared with 37% (95% CI, 29%-46%) among KEAP1-wildtype tumors (P = 0.041). Patients with CDKN2A-altered tumors had an increased incidence of leptomeningeal disease (LMD) as a form of intracranial progression. The 24-month cumulative incidence of LMD amongst CDKN2A-altered tumors was 11% (95% CI, 2.7%-27%) compared with 4.1% (95% CI, 1.5%-8.8%) among CDKN2A-wildtype tumors (P = 0.023).

CONCLUSION

In our cohort of molecularly profiled KRAS-mutant lung adenocarcinoma BM patients treated with SRS, we found that co-occurring KEAP1 and STK11 were significantly associated with worse iPFS. We also observed that CDKN2A co-altered tumors had an increased incidence of LMD. These findings have implications for future efforts to personalize brain metastasis management based on comprehensive genomic profiling.

A framework to rank genomic alterations as targets for cancer precision medicine: the ESMO Scale for Clinical Actionability of molecular Targets (ESCAT)

Background

In order to facilitate implementation of precision medicine in clinical management of cancer, there is a need to harmonise and standardise the reporting and interpretation of clinically relevant genomics data.

Methods

The European Society for Medical Oncology (ESMO) Translational Research and Precision Medicine Working Group (TR and PM WG) launched a collaborative project to propose a classification system for molecular aberrations based on the evidence available supporting their value as clinical targets. A group of experts from several institutions was assembled to review available evidence, reach a consensus on grading criteria and present a classification system. This was then reviewed, amended and finally approved by the ESMO TR and PM WG and the ESMO leadership.

Results

This first version of the ESMO Scale of Clinical Actionability for molecular Targets (ESCAT) defines six levels of clinical evidence for molecular targets according to the implications for patient management: tier I, targets ready for implementation in routine clinical decisions; tier II, investigational targets that likely define a patient population that benefits from a targeted drug but additional data are needed; tier III, clinical benefit previously demonstrated in other tumour types or for similar molecular targets; tier IV, preclinical evidence of actionability; tier V, evidence supporting co-targeting approaches; and tier X, lack of evidence for actionability.

Conclusions

The ESCAT defines clinical evidence-based criteria to prioritise genomic alterations as markers to select patients for targeted therapies. This classification system aims to offer a common language for all the relevant stakeholders in cancer medicine and drug development.

EGFR mutation subtypes and response to immune checkpoint blockade treatment in non-small-cell lung cancer

BACKGROUND

Although EGFR mutant tumors exhibit low response rates to immune checkpoint blockade overall, some EGFR mutant tumors do respond to these therapies; however, there is a lack of understanding of the characteristics of EGFR mutant lung tumors responsive to immune checkpoint blockade.

PATIENTS AND METHODS

We retrospectively analyzed de-identified clinical and molecular data on 171 cases of EGFR mutant lung tumors treated with immune checkpoint inhibitors from the Yale Cancer Center, Memorial Sloan Kettering Cancer Center, University of California Los Angeles, and Dana Farber Cancer Institute. A separate cohort of 383 EGFR mutant lung cancer cases with sequencing data available from the Yale Cancer Center, Memorial Sloan Kettering Cancer Center, and The Cancer Genome Atlas was compiled to assess the relationship between tumor mutation burden and specific EGFR alterations.

RESULTS

Compared with 212 EGFR wild-type lung cancers, outcomes with programmed cell death 1 or programmed death-ligand 1 (PD-(L)1) blockade were worse in patients with lung tumors harboring alterations in exon 19 of EGFR (EGFRΔ19) but similar for EGFRL858R lung tumors. EGFRT790M status and PD-L1 expression did not impact response or survival outcomes to immune checkpoint blockade. PD-L1 expression was similar across EGFR alleles. Lung tumors with EGFRΔ19 alterations harbored a lower tumor mutation burden compared with EGFRL858R lung tumors despite similar smoking history.

CONCLUSIONS

EGFR mutant tumors have generally low response to immune checkpoint inhibitors, but outcomes vary by allele. Understanding the heterogeneity of EGFR mutant tumors may be informative for establishing the benefits and uses of PD-(L)1 therapies for patients with this disease.

Investigating best practices of district-wide physical activity programmatic efforts in US schools- a mixed-methods approach

Background

The majority of US children do not meet physical activity recommendations. Schools are an important environment for promoting physical activity in children, yet most school districts do not offer enough physical activity opportunities to meet recommendations. This study aimed to identify school districts across the country that demonstrated exemplary efforts to provide students with many physical activity opportunities and to understand the factors that facilitated their programmatic success.

Methods

A total of 59 districts were identified as model districts by members of the Physical Activity and Health Innovation Collaborative, an ad hoc activity associated with the Roundtable on Obesity Solutions at the National Academies of Sciences, Engineering, and Medicine. Semi-structured interviews were conducted with consenting stakeholders from 23 school districts to understand physical education and activity efforts and elucidate factors that led to the success of these districts’ physical activity programming. Districts were geographically and socioeconomically diverse and varied in their administrative and funding structure.

Results

Most districts did not offer the recommended 150 or 225 min of physical activity a week through physical education alone; yet all districts offered a range of programs outside of physical education that provided additional opportunities for students to be physically active. The average number of school-based physical activity programs offered was 5.5, 3.5 and 2.1 for elementary, middle and high schools, respectively. Three overarching and broadly relevant themes were identified that were associated with successfully enhancing physical activity opportunities for students: soliciting and maintaining the support of champions, securing funding and/or tangible support, and fostering bi-directional partnerships between the district and community organizations and programs. Not only were these three themes critical for the development of physical activity opportunities, but they also remained important for the implementation, evaluation and sustainability of programs. These themes also did not differ substantially by the socioeconomic status of districts.

Conclusions

These findings demonstrate the success of school districts across the nation in providing ample opportunities for physical activity despite considerable variability in socioeconomic status and resources. These results can inform future research and provide actionable evidence for school districts to enhance physical activity opportunities to students.

Electronic supplementary material

The online version of this article (10.1186/s12889-018-5889-4) contains supplementary material, which is available to authorized users.

Clinical and molecular characterization of patients with cancer of unknown primary in the modern era

Background

On the basis of historical data, patients with cancer of unknown primary (CUP) are generally assumed to have a dismal prognosis with overall survival of less than 1 year. Treatment is typically cytotoxic chemotherapy guided by histologic features and the pattern of metastatic spread. The purpose of this study was to provide a clinical and pathologic description of patients with CUP in the modern era, to define the frequency of clinically actionable molecular alterations in this population, to determine how molecular testing can alter therapeutic decisions, and to investigate novel uses of next-generation sequencing in the evaluation and treatment of patients with CUP.

Patients and methods

Under Institutional Review Board approval, we identified all CUP patients evaluated at our institution over a recent 2-year period. We documented demographic information, clinical outcomes, pathologic evaluations, next-generation sequencing of available tumor tissue, use of targeted therapies, and clinical trial enrollment.

Results

We identified 333 patients with a diagnosis of CUP evaluated at our institution from 1 January 2014 through 30 June 2016. Of these patients, 150 had targeted next-generation sequencing carried out on available tissue. Median overall survival in this cohort was 13 months. Forty-five of 150 (30%) patients had potentially targetable genomic alterations identified by tumor molecular profiling, and 15 of 150 (10%) received targeted therapies. Dominant mutation signatures were identified in 21 of 150 (14%), largely implicating exogenous mutagen exposures such as ultraviolet radiation and tobacco.

Conclusions

Patients with CUP represent a heterogeneous population, harboring a variety of potentially targetable alterations. Next-generation sequencing may provide an opportunity for CUP patients to benefit from novel personalized therapies.

Oncologist use and perception of large panel next-generation tumor sequencing

BACKGROUND

Genomic profiling is increasingly incorporated into oncology research and the clinical care of cancer patients. We sought to determine physician perception and use of enterprise-scale clinical sequencing at our center, including whether testing changed management and the reasoning behind this decision-making.

PATIENTS AND METHODS

All physicians who consented patients to MSK-IMPACT, a next-generation hybridization capture assay, in tumor types where molecular profiling is not routinely performed were asked to complete a questionnaire for each patient. Physician determination of genomic 'actionability' was compared to an expertly curated knowledgebase of somatic variants. Reported management decisions were compared to chart review.

RESULTS

Responses were received from 146 physicians pertaining to 1932 patients diagnosed with 1 of 49 cancer types. Physicians indicated that sequencing altered management in 21% (331/1593) of patients in need of a treatment change. Among those in whom treatment was not altered, physicians indicated the presence of an actionable alteration in 55% (805/1474), however, only 45% (362/805) of these cases had a genomic variant annotated as actionable by expert curators. Further evaluation of these patients revealed that 66% (291/443) had a variant in a gene associated with biologic but not clinical evidence of actionability or a variant of unknown significance in a gene with at least one known actionable alteration. Of the cases annotated as actionable by experts, physicians identified an actionable alteration in 81% (362/445). In total, 13% (245/1932) of patients were enrolled to a genomically matched trial.

CONCLUSION

Although physician and expert assessment differed, clinicians demonstrate substantial awareness of the genes associated with potential actionability and report using this knowledge to inform management in one in five patients.

CLINICAL TRIAL NUMBER

NCT01775072.

Veterans' Service Utilization Patterns After Alcohol and Opioid Detoxification in VHA Care

OBJECTIVE

This study aimed to examine detoxification-related service utilization in the Veterans Health Administration (VHA).

METHODS

VHA data for 266,908 patients were used to examine rates and predictors of receiving detoxification, attending post-detoxification appointments, and entering specialty treatment. Multilevel, mixed-effects logistic regressions were used to examine associations between patient and facility characteristics and service utilization.

RESULTS

Nationally, 8.0% of VHA patients with alcohol or opiate dependence received detoxification in fiscal year 2013 (facility range=.1%-20.4%); 43.1% of detoxified patients received follow-up (11.1%-76.4%), and 49.9% entered specialty treatment (13.0%-77.2%). In adjusted analyses, detoxification was more likely among male, younger, white, and homeless patients with documented alcohol or opiate disorders and comorbid general medical conditions but without previous addiction treatment. Detoxification was also more likely in facilities with fewer vacant addiction therapist positions. Follow-up and specialty treatments were more likely among younger, healthier homeless patients with previous addiction treatment and a documented alcohol use disorder.

CONCLUSIONS

Detoxification-related service utilization was highly variable across the VHA. Interventions are needed to optimize use.

Viral safety in homoeopathic medicinal products

To guarantee the safety of medicinal products as regards infectious agents, numerous national guidelines and recommendations have in recent years been included in the pharmacopoeia general monographs and have influenced the content of the substance monographs. Although the stipulations of the European Pharmacopoeia set out objectives, there is still a certain scope in how the requirements are implemented. This is reflected in the very different responses in Europe to the problems of safety from infection. Different traditions in the use of homoeopathic and anthroposophic therapy and varying levels of expertise among the regulatory authorities within the European Union have resulted in varying standard of assessment. The aim of this publication is to present a standard form of assessment for medicinal products in these therapeutic systems. Demonstrated hereunder is an approach that can be adopted to ensure that the high safety standard required is met for homoeopathic and anthroposophic medicinal products.

MAPKs are essential upstream signaling pathways in proteolytic cartilage degradation--divergence in pathways leading to aggrecanase and MMP-mediated articular cartilage degradation

OBJECTIVES

Matrix metalloproteinases (MMPs) and aggrecanases are essential players in cartilage degradation. However, the signaling pathways that results in MMP and/or aggrecanase synthesis and activation are not well understood. We investigated the molecular events leading to MMP- and aggrecanase-mediated cartilage degradation.

METHODS

Cartilage degradation was induced in bovine articular cartilage explants by oncostatin M (OSM) and tumor necrosis factor (TNF), in the presence or absence of specific inhibitors of the mitogen-activated protein kinases (MAPKs) P38, P44/42 and Src family. Toxicity was followed by the AlamarBlue colorimetric assay. MMP-activity was assessed using a fluorescent substrate assay and MMP-9 and -2 activities by gelatinase zymography. MMP-mediated collagen type II degradation and MMP as well as aggrecanase-mediated aggrecan degradation was investigated with specific ELISA and hydroxyproline release by standard methods. The findings were verified by immunohistochemistry and histology.

RESULTS

Stimulation of cartilage degradation by OSM+TNF resulted in 100-fold induction of CTX-II release (P<0.01). This was dose-dependently inhibited by MAPK P38 inhibitors and by the MAPK P44/42 inhibitors. MMP-activity and expression was significantly decreased, as evaluated by cleavage of fluorescence MMP-substrate and zymography. Immunohistochemistry confirmed these findings. Interestingly, only the P44/42 inhibitors abrogated aggrecanase-mediated aggrecan degradation.

CONCLUSION

We found that inhibition of MAPK P38, P44/42 and Src family abrogated proteolytic cartilage degradation by blocking MMP synthesis and activity. However, only MAPK P44/42 was essential for aggrecanase-mediated aggrecan degradation. These data suggest that various aspects of cartilage degradation can be targeted independently by inhibiting specific upstream signaling pathway.

Kinetics and dose-response of residual 53BP1/γ-H2AX foci: Co-localization, relationship with DSB repair and clonogenic survival

PURPOSE

Recent studies revealed that some foci produced by phosphorylated histone 2A family member X (gamma-H2AX) and tumor suppressor p53 binding protein 1 (53BP1) that co-localize with radiation-induced DNA double-strand breaks (DSB) remain in cells at relatively long times after irradiation and indicated a possible correlation between cellular radiosensitivity and residual foci. In this study, we investigated dose-responses and kinetics for radiation-induced 53BP1/gamma-H2AX foci formation in relation to their co-localization, DSB repair and cell survival.

MATERIALS AND METHODS

Cell survival, DSB and foci were analyzed by clonogenic assay, pulsed field gel electrophoresis (PFGE), and confocal laser microscopy, respectively, in normal human fibroblasts (VH-10) and in a cancer cell line (HeLa). Computer analysis was used to determine both the number and the area of foci.

RESULTS

We show that even at doses down to 1 cGy a statistically significant induction of 53BP1 foci is observed. While the number of foci was found to constantly decrease with post-irradiation time, the per-cell normalized area of foci does not change within a time window of approximately 4 h post-irradiation. Co-localization of gamma-H2AX and 53BP1 foci is shown to depend on dose and post-irradiation time. No clear correlations were established between radiosensitivity and foci formation because the dose response for 53BP1/gamma-H2AX foci may depend on time after irradiation and duration of the cell cycle. We show that the kinetics of foci disappearance within 24 h post-irradiation do not coincide with those of DSB repair.

CONCLUSIONS

The data suggest that the post-irradiation time used for estimation of radiosensitivity at therapeutically relevant low doses (e.g., <3 Gy) in proliferating cells by scoring residual foci should be limited by the duration of the cell cycle, and that direct comparison of the kinetics of DSB repair and disappearance of DSB-co-localizing foci is not possible. Therefore, results obtained from the counting of foci should be interpreted with caution in terms of DSB repair.

Increased expression of androgen receptor (AR) and enzymes involved in androgen synthesis in metastatic prostate cancer: Targets for novel personalized therapies

5002

Background: Androgen receptor (AR) signaling remains active in castration-resistant prostate cancer (CRPC) despite castrate levels of circulating androgens. This is indicated by continuous expression of androgen-responsive genes and is due to mechanisms that include: increased AR expression; AR mutations allowing promiscuous activation by alternative ligands; and increased intratumoral androgen levels, resulting from in situ steroidogenesis. Methods: Gene expression profiles of 30 normal prostate tissue samples, 131 primary prostate carcinomas (PCas) and 16 metastatic PCas, generated using Affymetrix Exon arrays, were interrogated for levels of 40 mRNAs encoding AR, SHBG, 28 enzymes involved in androgen synthesis and 10 enzymes involved in androgen inactivation. For individual tumors, a transcript was considered to be overexpressed or underexpressed when its levels were >2 SDs higher or lower, respectively, than its average levels in normal tissue. Results: Metastatic PCas expressed higher average transcript levels for AR and several steroidogenic enzymes, including SRD5A1 and SRD5A3, than primary PCas and normal prostate tissue. Expression of SRD5A2, CYP3A4, CYP3A5, and CYP3A7 mRNAs was decreased both in primary and metastatic tumors compared to normal prostate tissue. In analysis involving AR and 28 steroidogenic transcripts in individual tumors, all (16/16) metastatic PCas overexpressed at least one transcript (range: 2–14, median: 5 transcripts) compared to normal tissue, while 100/131 (76%) primary PCas overexpressed at least one transcript (range: 2–16, median: 2). Conclusions: Metastatic PCas overexpress AR and several steroidogenic enzymes, while they express lower levels of the androgen-inactivating enzymes CYP3A4, CYP3A5, and CYP3A7. These data highlight the role of AR and the androgen synthetic pathway as a therapeutic target in CRPC. Novel antiandrogens (MDV3100) and CYP17 inhibitors (abiraterone) are already in clinical trials in CRPC. Overexpression of AR or steroidogenic enzymes may serve as a biomarker (e.g. by detection via RT-PCR in circulating tumor cells) to predict for sensitivity to these agents and guide patient selection for participation in clinical trials.

No significant financial relationships to disclose.

RAD51C (RAD51L2) is involved in maintaining centrosome number in mitosis

The RAD51C (RAD51L2) protein is one out of five RAD51 paralogs and forms a complex that includes either XRCC2 or XRCC3. Both of these complexes may have important functions in homologous recombination (HR). Here, we confirm that the frequency of DNA double-strand break (DSB)-induced HR is reduced in the RAD51C deficient cell line CL-V4B, in agreement with a role for RAD51C in HR. We report that mitotic RAD51C deficient CL-V4B cells also have an increased number of centrosomes in mitosis resulting in aberrant mitotic spindles. These data suggest that the RAD51C protein is important in maintaining correct centrosome numbers and that the complexes including RAD51C and XRCC2 or XRCC3 may be of importance in maintaining correct centrosome numbers in mitosis. Increased centrosome numbers following a RAD51C defect indicates that this protein might be important in preventing aneuploidy, suggesting that it could be a potential tumour suppressor in mammals.

Spindle positioning in fibroblasts supports an astral microtubule length dependent force generation at the basal membrane

V79 Chinese hamster fibroblasts that maintain an elongated shape in metaphase occur at a low frequency and often show the spindle asymmetrically positioned. We show here that this aberrant position is corrected in anaphase by an external force, pulling the spindle into place. The force was applied on astral microtubules because spindle motility was hampered when astral microtubules were poorly developed spontaneously, or destroyed by colcemid. Colcemid also abolished the observed downward positioning of centrosomes in anaphase. One pole of the spindle was usually dominant during correction, but occasionally both poles could become subject to pulling making the spindle move perpendicular to the long axis of the cell, which induced reshaping of the cell. The pulling force acted unevenly with short intervals of resting between the pulling. Spindle elongation also varied in rate but showed a different periodicity than translocation of the spindle, and therefore appeared independently regulated. The length of the spindle increased with the length of the cell, and the rate of spindle elongation and pole movement increased with distance moved, indicating that the forces mediated by astral microtubules increase with their length. Arp1/dynactin, not colocalising with tubulin, was more often continuous with microtubules in anaphase B than in metaphase, and was primarily located at the bottom of the cell. Further, shifts in the geometric gravity centre of the cell occurred in the same direction as migration of the spindle. To explain these results, we suggest that astral microtubles transiently anchored at the bottom of the cell are of particular importance for spindle translocation in fibroblasts.

Sensitivity of cytokinesis to hydrophobic interactions. Chemical induction of bi-and multinucleated cells

We have tested whether cytokinesis is as sensitive to hydrophobic interactions as karyokinesis, and evaluated the usefulness of the frequency of binucleated cells as end-point. Treating cultured cells for 2 or 24 h, with different lipophilic alcohols and chlorinated hydrocarbons made this possible. Colcemid and cytochalasin B were applied as positive controls for inhibition of karyokinesis and cytokinesis, respectively. Several-fold increases of binucleated cells could be seen with cytochalasin B after 2 h of treatment, while there was no increase with colcemid, which instead blocked cells in prometaphase/metaphase. The solvent acted primarily through hydrophobic interactions. For each solvent, the blocking of cells in prometaphase/metaphase and a minor increase in binucleated cells, were seen at approximately the same concentration; the binucleated cells probably emanated from cells in anaphase/telophase at the start of treatment. We conclude that the spindle function and cleavage show similar sensitivity to hydrophobic interactions. After prolonged treatment, allowing escape from the metaphase block, the solvents induced binucleated and multinucleated cells. By forming the quotient between multinucleated (MULTI) and binucleated (BIN) cells one could distinguish between effects primarily on the spindle or cytokinesis, respectively. All solvents, and a combination of colcemid and cytochalasin B, showed quotients intermediate between those observed with colcemid (high MULTI/BIN) and cytochalasin B (low MULTI/BIN), respectively. Both protocols revealed the same relationship between lowest active concentration and lipophilicity for the solvents, implying that concentration, not dose were of prime importance. The specific inhibitors acted at low concentrations in relation to lipophilicity, clearly demonstrating their chemical mechanisms. This approach can be used for rapid screening of potential aneugens, distinguishing between routes, and when lipophilicity is known, also reveal the principal mechanism of action, i.e. physico-chemical or chemical.

Cloning of novel transcripts of the human guanine-nucleotide-exchange factor Mss4: in situ chromosomal mapping and expression in pancreatic cancer

In a previous large-scale analysis of gene expression in pancreatic cancer using gridded arrays of cDNA libraries and differential hybridizations, a gene that was a homolog to human mss4 was identified. Mss4 is a guanine-nucleotide-exchange factor for the Sec4/ Ypt1/Rab family of small GTP-binding proteins involved in the regulation of intracellular vesicular transport. By fluorescence in situ hybridization the human mss4 gene was assigned to chromosome 1q32-q41. Northern blot analysis revealed that three mss4 mRNA species are transcribed in human tissues of 780, 1200, and 2800 bp in length, respectively. Cloning and sequencing of the human mss4 transcripts from a pancreatic cancer cDNA library revealed that these mRNA species differ in the length of the 3-untranslated region and are probably due to the alternate use of polyadenylation sites. All mRNA species were detected at moderate to high levels in pancreatic cancer cell lines and were overexpressed in pancreatic cancer tissue compared to both normal pancreas and chronic pancreatitis tissue. However, the 1200-bp transcript was the Mss4 mRNA species with the highest level of expression in more than 50% of tumor cells and tissues. High levels of expression were found as well in other human tumor tissues. Mss4 as guanine-exchange factor required in the regulation of intracellular transport may be of importance for the function and growth of human tumor cells. However, the precise role of mss4 in human tumor cells is unknown and remains to be elucidated.

The detection and evaluation of aneugenic chemicals

Although aneuploidy makes a significant contribution to both somatic and inherited disease the mechanisms by which environmental chemicals may induce numerical chromosome aberrations are only poorly defined. The European Union Project was aimed to further our understanding of those chemical interactions with the components of the mitotic and meiotic cell division cycle which may lead to aneuploidy and to characterise the parameters such as cellular metabolism which may influence the activity of aneugenic chemicals. C-mitosis can be induced by the highly lipophilic polychlorinated biphenyl and the completion of mitosis and cleavage can be modified by agents which deplete cellular levels of reduced glutathione. Modifications of the fidelity of chromosome segregation were produced by inhibiting the functioning of topoisomerase II during chromatid separation. In contrast, the modification of centromere integrity resulted in chromosome breakage as opposed to disturbance of segregation. Modifiers of tubulin assembly and centriolar functioning in somatic cells such as acrylamide, vinblastine and diazepam reproduced their activity in rodent bone marrow and male germ cells. The analysis of chromosome malsegregation in Aspergillus nidulans by a structurally related series of halogenated hydrocarbons was used to develop a QSAR model which had high predictive value for the results of fungal tests for previously untested related chemicals. Metabolic studies of potential aneugens in genetically engineered human lymphoblastoid cells demonstrated the detoxification of the aneugenic activity of chloral hydrate and the activation of 2,3-dichlorobutane, 1,1,2-trichloroethane and trichloroethylene by Phase I biotransforming enzymes. Cell transformation studies in Syrian hamster dermal cultures using a panel of 22 reference and or potential aneugens indicated that 15 of the 22 produced positive results following single exposures. Five of the aneugens which were negative following single exposures produced positive results where cultures were continuously exposed for up to 6 weeks to low concentrations following a single non-transforming exposure to the mutagen dimethyl sulphate. The transformation studies indicate that a significant proportion of chemical aneugens are potential complete carcinogens and/or co-carcinogens. To optimise the enumeration of chromosomes following exposure to potential chemical aneugens whole chromosome paints and centromere specific probes suitable for use in fluorescence in situ hybridisation (FISH) were developed for the rat, mouse and Chinese hamster and selected human probes evaluated for their suitability for routine use. Molecular chromosome probes were used to develop protocols for enumerating chromosomes in metaphase cells and centromeres and micronuclei in interphase cells. The analysis of segregation of specific centromeres in binucleate cells following cytochalasin B treatment was shown to be a potentially valuable system for characterising non-disjunction following chemical exposure. Whole chromosome paints and centromere specific probes were used to demonstrate the presence of dose-response thresholds following treatment with a reference panel of spindle inhibiting chemicals. These data indicate that the FISH technology is suitable for evaluating the relative hazards of low-dose exposures to aneugenic chemicals.

Effect of DETOX as an adjuvant for melanoma vaccine

The identification of effective adjuvants is critical for tumor vaccine development. Towards this end, we examined whether the immunogenicity of a melanoma vaccine could be potentiated by DETOX, an adjuvant consisting of monophosphoryl lipid A (MPL) and purified mycobacterial cell-wall skeleton (CWS). Nineteen patients with resected stage III melanoma were immunized with a polyvalent melanoma antigen vaccine (40 micrograms) admixed with DETOX, q3 wks x 4. Seven patients received vaccine + low-dose DETOX (10 micrograms MPL + 100 micrograms CWS) and 12 received vaccine + high-dose DETOX (20 micrograms MPL + 200 micrograms CWS). A non-randomized control group of 35 patients was treated similarly with 40 micrograms vaccine + alum. One week after the fourth vaccine immunization, melanoma antibodies were increased over baseline in 7/7 (100%) patients treated with vaccine + low-dose DETOX, 8/12 (67%) patients treated with vaccine + high-dose DETOX, and in 4/19 (21%) of vaccine + alum patients. For the entire DETOX group, the antibody response rate was 15/19 (79%) compared 4/19 (21%) in the alum group (p < 0.001). In contrast, a strong delayed-type hypersensitivity (DTH) response (> or = 15 mm increase in DTH response over baseline) was induced in 50% of the entire DETOX group versus in 47% of the alum group. Median disease-free (DF) survival for the entire DETOX group was 17.8 months compared with 32.1 months in the alum group (p < 0.05). In conclusion, DETOX markedly potentiated antibody but had little effect on DTH responses to melanoma vaccine immunization. It did not appear to improve disease-free survival in comparison to alum in this non-randomized study.

Video time-lapse study of mitosis in binucleate V79 cells: chromosome segregation and cleavage

Binucleate V79 Chinese hamster cells were video time-lapse recorded during mitosis. The general pattern found was: formation of one integrated metaphase plate, most often in a tetra- or tripolar spindle, prolonged prometaphase/metaphase, and normal duration of anaphase and contraction of cleavage furrows. Cleavage, however, often showed partial regression. Reversal of cleavage usually occurred late and then was not clearly separable from fusion of daughter cells. Reversal/fusion was more common the more furrows were initiated in late anaphase. This suggests that a final part of cleavage, or establishment of daughter cell integrity, is hampered by the preceding complex chromosome/spindle arrangements in the binucleate cells. Lagging of chromosomes in anaphase and formation of micronuclei were found to be frequent events. The nuclei formed from cells with a tetra- or tripolar spindle were often uneven in size, suggesting that the cells have difficulties in distributing the chromosomes in an organized way between many poles. A comparison with previous studies of binucleate mitoses in other cell lines shows major similarities in the mitotic performance. It is suggested that induction of binucleate cells should be included as a relevant end point when screening novel compounds for toxicity and aneuploidy.

Double-masked, paired-comparison clinical study of ketorolac tromethamine 0.5% ophthalmic solution compared with placebo eyedrops in the treatment of seasonal allergic conjunctivitis

In a multicenter, double-masked, clinical study, we compared the ocular safety and efficacy of ketorolac 0.5% ophthalmic solution with placebo in alleviating the signs and symptoms of allergic conjunctivitis. The study was conducted in 93 patients who received one drop of the appropriate treatments in each eye, four times a day, for seven days. Of these subjects, 74 were evaluated for efficacy. The principal clinical sign of allergic conjunctivitis, conjunctival inflammation, and six allergic symptoms (itching, swollen eyes, burning or stinging, discharge or tearing, foreign body sensation, and photophobia) were evaluated by the investigators at midweek (day 3 or 4) and at the end of the study (day 7 or 8). Ketorolac was superior to placebo in reducing conjunctival inflammation (p = 0.003) and itching (p = 0.020), the principal clinical symptom, at the final examination. In addition, ketorolac was favored over placebo in reducing the other five symptoms evaluated. On the day of final examination, overall therapeutic response evaluated by the investigators rated ketorolac as superior to placebo (p = 0.007). A significant placebo effect was noted in this study, as has been previously reported in clinical studies of allergic conjunctivitis patients. Results of this study demonstrate that 0.5% ketorolac ophthalmic solution used topically four times daily, for seven days, was effective in alleviating the principal sign and the symptoms associated with allergic conjunctivitis.

Effects of tamoxifen on corpus luteum function and luteal phase length in cynomolgus monkeys

Previous data in nonhuman primates have demonstrated that tamoxifen prolongs the luteal phase without altering reproductive hormone levels. A small study in humans found no effect on menstrual cycle length, but an increase in luteal ovarian steroid levels. In view of these conflicting results, we studied the effect of tamoxifen on corpus luteum (CL) function in monkeys (n = 20). Blood was obtained daily beginning cycle day 8, and sera assayed for estradiol (E2), progesterone (P), luteinizing hormone, and follicle-stimulating hormone. Four days after the midcycle E2 peak, laparoscopy confirmed CL formation, and the animals were administered (1) lactose (n = 7), (2) tamoxifen, 0.5 mg.kg-1.d-1 (n = 6), or (3) tamoxifen, 3.0 mg.kg-1.d-1 (n = 7) for 12 consecutive days. Serum collection continued until cycle day 50 or menses, whichever came first. Results indicate a biphasic response among tamoxifen-treated animals, with 7 of 13 developing prolonged luteal phases. There was, however, no significant difference in luteal phase length among the three groups, although when the two groups given tamoxifen were combined, the difference in luteal phase length versus controls approached significance. No differences were found among peak P levels, mean luteal phase P levels, or mean luteal phase gonadotropin levels. No variables were found to correlate significantly with luteal phase length. These results suggest that luteal phase administration of the antiestrogen tamoxifen does not alter pituitary gonadotropin secretion or CL function. However, tamoxifen does prolong luteal phase length in a subset of monkeys, perhaps via a direct effect on the endometrium.