Labor and skills gap analysis of the biomedical research workforce.

The United States has experienced an unsustainable increase of the biomedical research workforce over the past 3 decades. This expansion has led to a myriad of consequences, including an imbalance in the number of researchers and available tenure-track faculty positions, extended postdoctoral training periods, increasing age of investigators at first U.S. National Institutes of Health R01 grant, and exodus of talented individuals seeking careers beyond traditional academe. Without accurate data on the biomedical research labor market, challenges will remain in resolving these problems and in advising trainees of viable career options and the skills necessary to be productive in their careers. We analyzed workforce trends, integrating both traditional labor market information and real-time job data. We generated a profile of the current biomedical research workforce, performed labor gap analyses of occupations in the workforce at regional and national levels, and assessed skill transferability between core and complementary occupations. We conclude that although supply into the workforce and the number of job postings for occupations within that workforce have grown over the past decade, supply continues to outstrip demand. Moreover, we identify practical skill sets from real-time job postings to optimally equip trainees for an array of careers to effectively meet future workforce demand.-Mason, J. L., Johnston, E., Berndt, S., Segal, K., Lei, M., Wiest, J. S. Labor and skills gap analysis of the biomedical research workforce.

Endothelial cell tube formation assay for the in vitro study of angiogenesis.

Angiogenesis is a vital process for normal tissue development and wound healing, but is also associated with a variety of pathological conditions. Using this protocol, angiogenesis may be measured in vitro in a fast, quantifiable manner. Primary or immortalized endothelial cells are mixed with conditioned media and plated on basement membrane matrix. The endothelial cells form capillary like structures in response to angiogenic signals found in conditioned media. The tube formation occurs quickly with endothelial cells beginning to align themselves within 1 hr and lumen-containing tubules beginning to appear within 2 hr. Tubes can be visualized using a phase contrast inverted microscope, or the cells can be treated with calcein AM prior to the assay and tubes visualized through fluorescence or confocal microscopy. The number of branch sites/nodes, loops/meshes, or number or length of tubes formed can be easily quantified as a measure of in vitro angiogenesis. In summary, this assay can be used to identify genes and pathways that are involved in the promotion or inhibition of angiogenesis in a rapid, reproducible, and quantitative manner.

Future directions for postdoctoral training in cancer prevention: insights from a panel of experts.

Cancer prevention postdoctoral fellowships have existed since the 1970s. The National Cancer Institute facilitated a meeting by a panel of experts in April 2013 to consider four important topics for future directions for cancer prevention postdoctoral training programs: (i) future research needs; (ii) underrepresented disciplines; (iii) curriculum; and (iv) career preparation. Panelists proffered several areas needing more research or emphasis, ranging from computational science to culture. Health care providers, along with persons from nontraditional disciplines in scientific training programs such as engineers and lawyers, were among those recognized as being underrepresented in training programs. Curriculum suggestions were that fellows receive training in topics such as leadership and human relations, in addition to learning the principles of epidemiology, cancer biologic mechanisms, and behavioral science. For career preparation, there was a clear recognition of the diversity of employment options available besides academic positions, and that program leaders should do more to help fellows identify and prepare for different career paths. The major topics and strategies covered at this meeting can help form the basis for cancer prevention training program leaders to consider modifications or new directions, and keep them updated with the changing scientific and employment climate for doctoral degree recipients and postdoctoral fellows.

Tpl2 knockout keratinocytes have increased biomarkers for invasion and metastasis.

Skin cancer is the most common form of cancer in the USA, with an estimated two million cases diagnosed annually. Tumor progression locus 2 (Tpl2), also known as MAP3K8, is a serine/threonine protein kinase in the mitogen-activated protein kinase signal transduction cascade. Tpl2 was identified by our laboratory as having a tumor suppressor function in skin carcinogenesis, with the absence of this gene contributing to heightened inflammation and increased skin carcinogenesis. In this study, we used gene expression profiling to compare expression levels between Tpl2 (+/+) and Tpl2 (-) (/-) keratinocytes. We identified over 2000 genes as being differentially expressed between genotypes. Functional annotation analysis identified cancer, cell growth/proliferation, cell death, cell development, cell movement and cell signaling as the top biological processes to be differentially regulated between genotypes. Further microarray analysis identified several candidate genes, including Mmp1b, Mmp2, Mmp9 and Mmp13, involved in migration and invasion to be upregulated in Tpl2 (-) (/-) keratinocytes. Moreover, Tpl2 (-/-) keratinocytes had a significant downregulation in the matrix metalloproteinase (MMP) inhibitor Timp3. Real-time PCR validated the upregulation of the MMPs in Tpl2 (-/-) keratinocytes and zymography confirmed that MMP2 and MMP9 activity was higher in conditioned media from Tpl2 (-/-) keratinocytes. Immunohistochemistry confirmed higher MMP9 staining in 12-O-tetradecanoylphorbol-13-acetate-treated skin from Tpl2 (-/-) mice and grafted tumors formed from v-ras(Ha) retrovirus-infected Tpl2 (-/-) keratinocytes. Additionally, Tpl2 (-/-) keratinocytes had significantly higher invasion, malignant conversion rates and increased endothelial cell tube formation when compared with Tpl2 (+/+) keratinocytes. In summary, our studies reveal that keratinocytes from Tpl2 (-/-) mice demonstrate a higher potential to be invasive and metastatic.

TUSC1, a putative tumor suppressor gene, reduces tumor cell growth in vitro and tumor growth in vivo.

We previously reported the identification of TUSC1 (Tumor Suppressor Candidate 1), as a novel intronless gene isolated from a region of homozygous deletion at D9S126 on chromosome 9p in human lung cancer. In this study, we examine the differential expression of TUSC1 in human lung cancer cell lines by western blot and in a primary human lung cancer tissue microarray by immunohistochemical analysis. We also tested the functional activities and mechanisms of TUSC1 as a tumor suppressor gene through growth suppression in vitro and in vivo. The results showed no expression of TUSC1 in TUSC1 homozygously deleted cells and diminished expression in some tumor cell lines without TUSC1 deletion. Interestingly, the results from a primary human lung cancer tissue microarray suggested that higher expression of TUSC1 was correlated with increased survival times for lung cancer patients. Our data demonstrated that growth curves of tumor cell lines transfected with TUSC1 grew slower in vitro than those transfected with the empty vector. More importantly, xenograph tumors in nude mice grew significantly slower in vivo in cells stably transfected with TUSC1 than those transfected with empty vector. In addition, results from confocal microscopy and immunohistochemical analyses show distribution of TUSC1 in the cytoplasm and nucleus in tumor cell lines and in normal and tumor cells in the lung cancer tissue microarray. Taken together, our results support TUSC1 has tumor suppressor activity as a candidate tumor suppressor gene located on chromosome 9p.

Altered prostanoid signaling contributes to increased skin tumorigenesis in Tpl2 knockout mice.

Squamous cell carcinoma is the second most common form of skin cancer with the incidence expected to double over the next 20 years. Inflammation is believed to be a critical component in skin cancer progression. Therefore, understanding genes involved in the regulation of inflammatory pathways is vital to the design of targeted therapies. Numerous studies show cyclooxygenases (COXs) play an essential role in inflammation-associated cancers. Tpl2 (MAP3K8) is a protein kinase in the MAP Kinase signal transduction cascade. Previous research using a two-stage skin carcinogenesis model revealed that Tpl2(-/-) mice have significantly higher tumor incidence and inflammatory response than wild-type (WT) controls. The current study investigates whether cyclooxygenase-2 (COX-2) and COX-2- regulated prostaglandins and prostaglandin receptors drive the highly tumorigenic state of Tpl2(-/-) mice by investigating the relationship between Tpl2 and COX-2. Keratinocytes from newborn WT or Tpl2(-/-) mice were treated with 12-O-tetradecanoylphorbol-13-acetate (TPA) for various times over 24 hours. Western analysis revealed significant differences in COX-2 and COX-2 dependent prostanoids and prostanoid receptors. Additionally, in vivo experiments confirmed that COX-2 and COX-2 downstream factors were elevated in TPA-treated Tpl2(-/-) skin, as well as in papillomas from Tpl2(-/-) mice. Use of the selective COX-2 inhibitor Celecoxib showed the increased tumorigenesis in the Tpl2(-/-) mice to primarily be mediated through COX-2. These experiments illustrate COX-2 induction in the absence of Tpl2 may be responsible for the increased tumorigenesis found in Tpl2(-/-) mice. Defining the relationship between Tpl2 and COX-2 may lead to new ways to downregulate COX-2 through the modulation of Tpl2.

Outcome evaluation of the National Cancer Institute career development awards program.

The National Cancer Institute (NCI) career development (K) awards program supports investigators to develop their cancer research programs and achieve independence. The NCI Center for Cancer Training conducted a K program evaluation by analyzing outcomes of awardees and individuals who applied to the program but were not funded. The evaluation covered seven NCI mechanisms (K01, K07, K08, K11, K22, K23, and K25) between 1980 and 2008. Descriptive statistics and regression modeling were performed on the full cohort (n = 2,893 individuals, 4,081 K applications) and a comparison cohort described herein. K awardees proportionately received more subsequent NIH grants and authored more publications, and time to first R01 grant was unaffected. Of those not pursuing research, K awardees were more likely to participate in activities signaling continued scientific engagement. The NCI K program had a positive impact, not only on participants' biomedical research careers but also on achieving outcomes significant to the scientific enterprise.

Expanding cancer prevention education to national and international audiences: the National Cancer Institute's Principles and Practice of Cancer Prevention and Control annual summer course.

The Summer Curriculum in Cancer Prevention has been sponsored by the National Cancer Institute's Cancer Prevention Fellowship Program for over two decades. This curriculum includes a 4-week course entitled "Principles and Practice of Cancer Prevention and Control." The ultimate goal of this course is to present the most current cancer prevention research to a diverse workforce of researchers and practitioners eager to address the current challenges in this field. The course covers the current status of cancer prevention research and practice, ranging from epidemiology and clinical practice, and from basic to behavioral science research. It is comprised of lectures grouped into nine modules representing broad and specific topics relevant to cancer prevention. Course participants come from a broad cross-section of career stages, professions, and research interests, and are from across the USA and other countries. Over time and in response to feedback from participants, the course has developed to meet the needs and expectations of this diverse audience, and may serve as a model for those interested in cancer prevention education and training in other countries.

A susceptibility locus on chromosome 6q greatly increases lung cancer risk among light and never smokers.

Cigarette smoking is the major cause for lung cancer, but genetic factors also affect susceptibility. We studied families that included multiple relatives affected by lung cancer. Results from linkage analysis showed strong evidence that a region of chromosome 6q affects lung cancer risk. To characterize the effects that this region of chromosome 6q region has on lung cancer risk, we identified a haplotype that segregated with lung cancer. We then performed Cox regression analysis to estimate the differential effects that smoking behaviors have on lung cancer risk according to whether each individual carried a risk-associated haplotype or could not be classified and was assigned unknown haplotypic status. We divided smoking exposures into never smokers, light smokers (<20 pack-years), moderate smokers (20 to <40 pack-years), and heavy smokers (>or=40 pack-years). Comparing results according to smoking behavior stratified by carrier status, compared with never smokers, there was weakly increasing risk for increasing smoking behaviors, with the hazards ratios being 3.44, 4.91, and 5.18, respectively, for light, moderate, or heavy smokers, whereas among the individuals from families without the risk haplotype, the risks associated with smoking increased strongly with exposure, the hazards ratios being, respectively, 4.25, 9.17, and 11.89 for light, moderate, and heavy smokers. The never smoking carriers had a 4.71-fold higher risk than the never smoking individuals without known risk haplotypes. These results identify a region of chromosome 6q that increases risk for lung cancer and that confers particularly higher risks to never and light smokers.

Haplotype and cell proliferation analyses of candidate lung cancer susceptibility genes on chromosome 15q24-25.1.

Recent genome-wide association studies have linked the chromosome 15q24-25.1 locus to nicotine addiction and lung cancer susceptibility. To refine the 15q24-25.1 locus, we performed a haplotype-based association analysis of 194 familial lung cases and 219 cancer-free controls from the Genetic Epidemiology of Lung Cancer Consortium (GELCC) collection, and used proliferation and apoptosis analyses to determine which gene(s) in the 15q24-25.1 locus mediates effects on lung cancer cell growth in vitro. We identified two distinct subregions, hapL (P = 3.20 x 10(-6)) and hapN (P = 1.51 x 10(-6)), which were significantly associated with familial lung cancer. hapL encompasses IREB2, LOC123688, and PSMA4, and hapN encompasses the three nicotinic acetylcholine receptor subunit genes CHRNA5, CHRNA3, and CHRNB4. Examination of the genes around hapL revealed that PSMA4 plays a role in promoting cancer cell proliferation. PSMA4 mRNA levels were increased in lung tumors compared with normal lung tissues. Down-regulation of PSMA4 expression decreased proteasome activity and induced apoptosis. Proteasome dysfunction leads to many diseases including cancer, and drugs that inhibit proteasome activity show promise as a form of cancer treatment. Genes around hapN were also investigated, but did not show any direct effect on lung cancer cell proliferation. We concluded that PSMA4 is a strong candidate mediator of lung cancer cell growth, and may directly affect lung cancer susceptibility through its modulation of cell proliferation and apoptosis.

Fine mapping of chromosome 6q23-25 region in familial lung cancer families reveals RGS17 as a likely candidate gene.

PURPOSE: We have previously mapped a major susceptibility locus influencing familial lung cancer risk to chromosome 6q23-25. However, the causal gene at this locus remains undetermined. In this study, we further refined this locus to identify a single candidate gene, by fine mapping using microsatellite markers and association studies using high-density single nucleotide polymorphisms (SNP). EXPERIMENTAL DESIGN: Six multigenerational families with five or more affected members were chosen for fine-mapping the 6q linkage region using microsatellite markers. For association mapping, we genotyped 24 6q-linked cases and 72 unrelated noncancer controls from the Genetic Epidemiology of Lung Cancer Consortium resources using the Affymetrix 500K chipset. Significant associations were validated in two independent familial lung cancer populations: 226 familial lung cases and 313 controls from the Genetic Epidemiology of Lung Cancer Consortium, and 154 familial cases and 325 controls from Mayo Clinic. Each familial case was chosen from one high-risk lung cancer family that has three or more affected members. RESULTS: A region-wide scan across 6q23-25 found significant association between lung cancer susceptibility and three single nucleotide polymorphisms in the first intron of the RGS17 gene. This association was further confirmed in two independent familial lung cancer populations. By quantitative real-time PCR analysis of matched tumor and normal human tissues, we found that RGS17 transcript accumulation is highly and consistently increased in sporadic lung cancers. Human lung tumor cell proliferation and tumorigenesis in nude mice are inhibited upon knockdown of RGS17 levels. CONCLUSION: RGS17 is a major candidate for the familial lung cancer susceptibility locus on chromosome 6q23-25.

Familial aggregation of common sequence variants on 15q24-25.1 in lung cancer.

Three recent genome-wide association studies identified associations between markers in the chromosomal region 15q24-25.1 and the risk of lung cancer. We conducted a genome-wide association analysis to investigate associations between single-nucleotide polymorphisms (SNPs) and the risk of lung cancer, in which we used blood DNA from 194 case patients with familial lung cancer and 219 cancer-free control subjects. We identified associations between common sequence variants at 15q24-25.1 (that spanned LOC123688 [a hypothetical gene], PSMA4, CHRNA3, CHRNA5, and CHRNB4) and lung cancer. The risk of lung cancer was more than fivefold higher among those subjects who had both a family history of lung cancer and two copies of high-risk alleles rs8034191 (odds ratio [OR] = 7.20, 95% confidence interval [CI] = 2.21 to 23.37) or rs1051730 (OR = 5.67, CI = 2.21 to 14.60, both of which were located in the 15q24-25.1 locus, than among control subjects. Thus, further research to elucidate causal variants in the 15q24-25.1 locus that are associated with lung cancer is warranted.

EGFR-T790M is a rare lung cancer susceptibility allele with enhanced kinase activity.

The use of tyrosine kinase inhibitors (TKI) has yielded great success in treatment of lung adenocarcinomas. However, patients who develop resistance to TKI treatment often acquire a somatic resistance mutation (T790M) located in the catalytic cleft of the epidermal growth factor receptor (EGFR) enzyme. Recently, a report describing EGFR-T790M as a germ-line mutation suggested that this mutation may be associated with inherited susceptibility to lung cancer. Contrary to previous reports, our analysis indicates that the T790M mutation confers increased Y992 and Y1068 phosphorylation levels. In a human bronchial epithelial cell line, overexpression of EGFR-T790M displayed a growth advantage over wild-type (WT) EGFR. We also screened 237 lung cancer family probands, in addition to 45 bronchoalveolar tumors, and found that none of them contained the EGFR-T790M mutation. Our observations show that EGFR-T790M provides a proliferative advantage with respect to WT EGFR and suggest that the enhanced kinase activity of this mutant is the basis for rare cases of inherited susceptibility to lung cancer.

Identification of a novel tumor suppressor gene p34 on human chromosome 6q25.1.

In this study, we observed loss of heterozygosity (LOH) in human chromosomal fragment 6q25.1 in sporadic lung cancer patients. LOH was observed in 65% of the 26 lung tumors examined and was narrowed down to a 2.2-Mb region. Single-nucleotide polymorphism (SNP) analysis of genes located within this region identified a candidate gene, termed p34. This gene, also designated as ZC3H12D, C6orf95, FLJ46041, or dJ281H8.1, carries an A/G nonsynonymous SNP at codon 106, which alters the amino acid from lysine to arginine. Nearly 73% of heterozygous lung cancer tissues with LOH and the A/G SNP also exhibited loss of the A allele. In vitro clonogenic and in vivo nude mouse studies showed that overexpression of the A allele exerts tumor suppressor function compared with the G allele. p34 is located within a recently mapped human lung cancer susceptibility locus, and association of the p34 A/G SNP was tested among these families. No significant association between the less frequent G allele and lung cancer susceptibility was found. Our results suggest that p34 may be a novel tumor suppressor gene involved in sporadic lung cancer but it seems not to be the candidate familial lung cancer susceptibility gene linked to chromosomal region 6q23-25.

The biology of tobacco and nicotine: bench to bedside.

Strong epidemiologic evidence links smoking and cancer. An increased understanding of the molecular biology of tobacco-related cancers could advance progress toward improving smoking cessation and patient management. Knowledge gaps between tobacco addiction, tumorigenesis, and cancer brought an interdisciplinary group of investigators together to discuss "The Biology of Nicotine and Tobacco: Bench to Bedside." Presentations on the signaling pathways and pathogenesis in tobacco-related cancers, mouse models of addiction, imaging and regulation of nicotinic receptors, the genetic basis for tobacco carcinogenesis and development of lung cancer, and molecular mechanisms of carcinogenesis were heard. Importantly, new opportunities to use molecular biology to identify and abrogate tobacco-mediated carcinogenesis and to identify high-risk individuals were recognized.

Mutational activation of the MAP3K8 protooncogene in lung cancer.

The MAP3K8 protooncogene (Cot/Tpl-2) activates the MAP kinase, SAP kinase, and NF-kappaB signaling pathways. MAP3K8 mutations occur in the rat homologue, but activating mutations have yet to be identified in primary human tumors. We have identified MAP3K8 as a transforming gene from a human lung adenocarcinoma and characterized a 3' end mutation in the cDNA. In addition, we confirmed that the mutation occurs in the original lung tumor, and we screened a series of lung cancer cell lines to determine whether the MAP3K8 mutation is a common occurrence in lung tumorigenesis. The oncogene was isolated and identified with the NIH3T3 nude mouse tumorigenicity assay and cDNA library screening. The gene was analyzed by polymerase chain reaction (PCR), single-strand conformational polymorphism (SSCP), and 3'RACE for mutations. The mutation was localized to MAP3K8 exon 8 and confirmed in the primary tumor DNA. Both wild-type and mutant MAP3K8 cDNAs transformed NIH3T3 cells, but the transforming activity of the mutant was much greater than that of the wild type. PCR-SSCP screening of cell line cDNAs identified one silent polymorphism in cell line SK-LU-1. Although we were unable to find additional activating mutations, these data support a role for MAP3K8 activity in cellular transformation, but suggest that mutational activation of the gene is a rare event in lung cancer.

Identifying novel homozygous deletions by microsatellite analysis and characterization of tumor suppressor candidate 1 gene, TUSC1, on chromosome 9p in human lung cancer.

Loss of heterozygosity (LOH) studies indicate that genetic alterations of chromosome 9p occur in numerous tumor types, suggesting the presence of tumor suppressor genes (TSGs) on chromosome 9p critical in carcinogenesis. Our previous LOH analyses in primary lung tumors led us to propose that chromosome 9p harbors other TSGs important in lung tumorigenesis. In this study, 30 non-small-cell lung cancer and 12 small-cell lung cancer cell lines were screened with 55 markers to identify new regions of homozygous deletion (HD) on chromosome 9p. Three novel noncontiguous homozygously deleted regions were detected and ranged in size from 840 kb to 7.4 Mb. One gene identified in the deletion at D9S126, TUSC1 (tumor suppressor candidate 1), is an intronless gene. Multiplex polymerase chain reaction and Southern blot confirmed the HD of TUSC1. Northern blot analysis of TUSC1 demonstrated two transcripts of approximately 2 and 1.5 kb that are likely generated by alternative polyadenylation signals. Both transcripts are expressed in several human tissues and share an open-reading frame encoding a peptide of 209 amino acids. Analysing cell line cDNAs by reverse transcriptase (RT)-PCR demonstrated downregulation of TUSC1 in cell lines with or without HDs, suggesting that TUSC1 may play a role in lung tumorigenesis.

LOH of chromosome 12p correlates with Kras2 mutation in non-small cell lung cancer.

Previous observation has shown that the wild-type Kras2 allele is a suppressor of lung cancer in mice. Here we report that loss of heterozygosity (LOH) of chromosome 12p was detected in approximately 50% of human lung adenocarcinomas and large cell carcinomas, and Kras2 mutations were detected at codon 12 in approximately 40% of adenocarcinomas and large cell carcinomas. Interestingly, all of the lung adenocarcinomas and large cell carcinomas containing a Kras2 mutation exhibited allelic loss of the wild-type Kras2 allele when a correlation between LOH of the region on chromosome 12p and Kras2 mutation was made. These results from human lung cancer tissues provide a strong evidence in support of our previous observation in mouse models that the wild-type Kras2 is a tumor suppressor of lung cancer.