Prospective study of colorectal cancer risk in men and plasma levels of insulin-like growth factor (IGF)-I and IGF-binding protein-3

BACKGROUND

Insulin-like growth factor-I (IGF-I) is a potent mitogen for normal and neoplastic cells, whereas IGF-binding protein-3 (IGFBP-3) inhibits cell growth in many experimental systems. Acromegalics, who have abnormally high levels of growth hormone and IGF-I, have higher rates of colorectal cancer. We therefore examined associations of plasma levels of IGF-I and IGFBP-3 with the risk of colorectal cancer in a prospective case-control study nested in the Physicians' Health Study.

METHODS

Plasma samples were collected at baseline from 14916 men without diagnosed cancer. IGF-I, IGF-II, and IGFBP-3 were assayed among 193 men later diagnosed with colorectal cancer during 14 years of follow-up and among 318 age- and smoking-matched control subjects. All P values are two-sided.

RESULTS

IGFBP-3 levels correlated with IGF-I levels (r=.64) and with IGF-II levels (r=.90). After controlling for IGFBP-3, age, smoking, body mass index (weight in kg/[height in m]2), and alcohol intake, men in the highest quintile for IGF-I had an increased risk of colorectal cancer compared with men in the lowest quintile (relative risk [RR]=2.51; 95% confidence interval [CI]=1.15-5.46; P for trend = .02). After controlling for IGF-I and other covariates, men with higher IGFBP-3 had a lower risk (RR=0.28; 95% CI=0.12-0.66; P for trend = .005, comparing extreme quintiles). The associations were consistent during the first and the second 7-year follow-up intervals and among younger and older men. IGF-II was not associated with risk.

CONCLUSIONS

Our findings suggest that circulating IGF-I and IGFBP-3 are related to future risk of colorectal cancer.

The genome of the natural genetic engineer Agrobacterium tumefaciens C58

The 5.67-megabase genome of the plant pathogen Agrobacterium tumefaciens C58 consists of a circular chromosome, a linear chromosome, and two plasmids. Extensive orthology and nucleotide colinearity between the genomes of A. tumefaciens and the plant symbiont Sinorhizobium meliloti suggest a recent evolutionary divergence. Their similarities include metabolic, transport, and regulatory systems that promote survival in the highly competitive rhizosphere; differences are apparent in their genome structure and virulence gene complement. Availability of the A. tumefaciens sequence will facilitate investigations into the molecular basis of pathogenesis and the evolutionary divergence of pathogenic and symbiotic lifestyles.

Structure of the bacteriophage phi29 DNA packaging motor

Motors generating mechanical force, powered by the hydrolysis of ATP, translocate double-stranded DNA into preformed capsids (proheads) of bacterial viruses and certain animal viruses. Here we describe the motor that packages the double-stranded DNA of the Bacillus subtilis bacteriophage phi29 into a precursor capsid. We determined the structure of the head-tail connector--the central component of the phi29 DNA packaging motor--to 3.2 A resolution by means of X-ray crystallography. We then fitted the connector into the electron densities of the prohead and of the partially packaged prohead as determined using cryo-electron microscopy and image reconstruction analysis. Our results suggest that the prohead plus dodecameric connector, prohead RNA, viral ATPase and DNA comprise a rotary motor with the head-prohead RNA-ATPase complex acting as a stator, the DNA acting as a spindle, and the connector as a ball-race. The helical nature of the DNA converts the rotary action of the connector into translation of the DNA.

Improved survival in stage III melanoma patients with GM2 antibodies: a randomized trial of adjuvant vaccination with GM2 ganglioside

PURPOSE

To perform a double-blind randomized trial with American Joint Commission on Cancer (AJCC) stage III melanoma patients for the following reasons: (1) to confirm our previous finding that patients with antibodies against the melanoma differentiation antigen GM2 have an improved prognosis, and (2) to demonstrate clinical benefit from GM2 antibody induction.

PATIENTS AND METHODS

One hundred twenty-two patients with AJCC stage III melanoma who were free of disease after surgery were randomized: 58 to receive treatment with the GM2/BCG vaccine, and 64 to receive treatment with bacille Calmette-Guèrin (BCG) alone. All patients were pretreated with low-dose cyclophosphamide (Cy).

RESULTS

GM2 antibody was detected in 50 of 58 patients treated with GM2/BCG and seven of 64 patients treated with BCG alone. With a minimum follow-up period of 51 months, there was a highly significant increase in the disease-free interval (P = .004) and a 17% increase in overall survival (P = .02) in these 57 antibody-positive patients, confirming our earlier experience. Exclusion of all patients with preexisting GM2 antibodies (one in the GM2/BCG group and five in the BCG group) from statistical analysis resulted in a 23% increase in disease-free interval (P = .02) and a 14% increase in overall survival (P = .15) at 51 months for patients treated with the GM2/BCG vaccine. However, when all patients in the two treatment groups were compared as randomized, these increases were 18% for disease-free interval and 11% for survival in the GM2/BCG treatment group, with neither result showing statistical significance.

CONCLUSION

(1) Vaccination with GM2/BCG induced immunoglobulin M (IgM) antibodies in most patients. (2) GM2 antibody production was associated with a prolonged disease-free interval and survival. (3) Comparison of the two arms of this trial as randomized fails to show a statistically significant improvement in disease-free interval or survival for patients treated with GM2/BCG vaccines.

Factors affecting long-term outcome after hepatic resection for hepatocellular carcinoma

BACKGROUND

Experience with hepatocellular carcinoma (HCC) is limited in the West and factors affecting outcome after resection are not clearly defined.

METHODS

Between 1970 and 1992, 106 patients (including 74 Caucasians, 31 Orientals, and 1 black) underwent hepatic resection for HCC at Memorial Sloan-Kettering Cancer Center. Clinical and histopathologic factors of outcome were analyzed.

RESULTS

Cirrhosis was present in 33% and 95% were Child-Pugh A. Operative mortality was 6%, 14% in cirrhotics versus 1% in non-cirrhotics (P = 0.013). Orientals had a higher prevalence of cirrhosis (68% versus 19%) (P < 0.0001) and smaller tumors (mean 8.7 cm versus 11.0 cm) (P = 0.028) compared to Caucasians. Overall survival was 41% and 32% at 5 and 10 years, respectively. By univariate analysis, survival was greater in association with the following: absence of vascular invasion (69% versus 28%, P = 0.002); absence of symptoms (66% versus 38%, P = 0.014); solitary tumor (53% versus 28%, P = 0.014); negative margins (46% versus 21%, P = 0.022); small tumor (< or = 5 cm) (75% versus 36%, P = 0.027); and presence of tumor capsule (69% versus 35%, P = 0.047). Ethnic origin, cirrhosis, necrosis and grade did not affect survival. By multivariate analysis, only vascular invasion predicted outcome (P = 0.0025, risk ratio 2.9).

CONCLUSIONS

One third of patients resected for HCC can be expected to survive long-term. Except for a higher incidence of cirrhosis in Orientals, no major histopathologic or prognostic differences were noted between Orientals and Caucasians undergoing resection. Early cirrhosis (Child-Pugh A) did not adversely affect survival. Vascular invasion predicted long-term outcome.

Decreased growth of established human prostate LNCaP tumors in nude mice fed a low-fat diet

BACKGROUND

Geographic variation in the incidence of clinically detected prostate cancer is considerable, with a 120-fold greater incidence in the United States than in China. The incidence of latent prostate cancer, however, shows little variation worldwide, with approximately 30% of men older than age 50 years having microfocal disease (determined by autopsy). Some epidemiologic studies have suggested that a high intake of dietary fat may constitute a risk factor for the development of advanced prostate cancer.

PURPOSE

We studied the influence of dietary fat content on the growth of tumors established in athymic nude mice with androgen-sensitive, human prostatic adenocarcinoma cells (LNCaP cells). We also investigated whether manipulation of dietary fat content altered prostate-specific antigen (PSA) production by these tumors.

METHODS

Tumors were induced in nude mice by subcutaneous injection of 10(6) LNCaP cells. Both the American Type Culture Collection (ATCC) LNCaP cell line and a more androgen-responsive subline derived from it (i.e., the Harris LNCaP cell line) were used. Mice were fed a 40.5-kcal% fat diet at the time of tumor cell injection. Three weeks later, after measurable tumors were formed, the animals were assigned to receive diets with one of the following fat contents: 40.5, 30.8, 21.2, 11.6, or 2.3 kcal% fat. Food intake, animal weights, and tumor volumes were recorded weekly; serum PSA and testosterone levels were measured at the termination of the study. Post hoc multiple comparisons were made using the Student-Newman-Keuls procedure. Two-sided tests of statistical significance were used to evaluate pairwise comparisons.

RESULTS

Tumor growth rates, final tumor weights, and ratios of final tumor weights to animal weights were substantially greater in groups that continued to receive a 40.5-kcal% fat diet than in groups whose diets were changed to 2.3 kcal%, 11.6 kcal%, or 21.2 kcal% fat (all P values < .04). Comparison of these parameters among the 2.3-kcal%, 11.6-kcal%, and 21.2-kcal% dietary fat groups did not reveal any statistically significant differences. No statistically significant differences were noted in total ingested calories, animal weight gain, serum testosterone levels, or histopathologic characteristics of the tumors among the tested dietary groups. Serum PSA levels were highest in the 40.5-kcal% fat group and lowest in the 2.3-kcal% fat group (evaluated only for ATCC LNCaP cells; P < .05).

CONCLUSIONS

Reduction of dietary fat substantially slows the growth of tumors established from human prostatic adenocarcinoma cells in a murine xenograft model. A positive association persists between tumor volumes and serum PSA levels even after extreme modification of dietary fat content.

Prognostic factors in patients with metastatic malignant melanoma. A multivariate analysis

BACKGROUND

Current methods to predict survival in patients with advanced, metastatic melanoma are limited. To determine clinical prognostic factors that accurately predict survival in patients with metastatic melanoma, a retrospective analysis was performed.

METHODS

Clinical, hematologic, and biochemical pretreatment parameters from 284 patients entered on 18 Phase I and II clinical trials were analyzed to determine their prognostic effect on survival. A multivariate parametric regression based on the Weibull distribution was derived to estimate survival.

RESULTS

Multivariate Weibull survival regression analysis showed that a simple model using the logarithm of the pretreatment values of lactate dehydrogenase and serum albumin, dichotomized as high and low, significantly and adequately predicted survival. A more complex multivariate model was also derived that involved the pretreatment platelet count, visceral organ involvement, and gender as additional factors. However, a larger study is needed to statistically validate such a model.

CONCLUSIONS

The pretreatment values of serum lactate dehydrogenase and albumin are independent prognostic factors for survival in patients with metastatic melanoma. These two factors can be used to estimate survival of patients with advanced, metastatic melanoma and should be considered when designing melanoma trials in which survival is an endpoint.

Octreotide as an antineoplastic agent in the treatment of functional and nonfunctional neuroendocrine tumors

BACKGROUND

Although patients with neuroendocrine tumors typically exhibit an indolent clinical course, the pace of disease accelerates and the prognosis deteriorates once objective progression of disease begins. Thirty-four patients with advanced neuroendocrine tumors were treated with octreotide as antineoplastic therapy. This treatment was begun only after documentation of clear objective progression of disease.

METHODS

A Phase II trial was performed at a tertiary comprehensive cancer center.

RESULTS

The median survival for this patient population from the start of octreotide therapy has not been reached, with a median follow-up of 29 months (range, 1-47 months). No major objective tumor regressions were seen. Seventeen patients (50%) experienced a computed tomography-documented stabilization of disease that was maintainable for a minimum of 2 months (median, 5 months; range, 0-27 months). Of the 34 patients, 20 patients received octreotide as their first antineoplastic therapy. The median survival for these 20 patients has not been reached, with a median follow-up also of 29 months (range, 12-41 months).

CONCLUSIONS

Octreotide may influence the natural history of neuroendocrine tumors. The survival in patients treated with octreotide, as measured from the time of progression of disease, compares favorably with that of historical controls. Proof of a survival advantage for patients treated with octreotide would require a multicenter, randomized trial.

Structure of bacteriophage T4 fibritin: a segmented coiled coil and the role of the C-terminal domain

BACKGROUND

Oligomeric coiled-coil motifs are found in numerous protein structures; among them is fibritin, a structural protein of bacteriophage T4, which belongs to a class of chaperones that catalyze a specific phage-assembly process. Fibritin promotes the assembly of the long tail fibers and their subsequent attachment to the tail baseplate; it is also a sensing device that controls the retraction of the long tail fibers in adverse environments and, thus, prevents infection. The structure of fibritin had been predicted from sequence and biochemical analyses to be mainly a triple-helical coiled coil. The determination of its structure at atomic resolution was expected to give insights into the assembly process and biological function of fibritin, and the properties of modified coiled-coil structures in general.

RESULTS

The three-dimensional structure of fibritin E, a deletion mutant of wild-type fibritin, was determined to 2.2 A resolution by X-ray crystallography. Three identical subunits of 119 amino acid residues form a trimeric parallel coiled-coil domain and a small globular C-terminal domain about a crystallographic threefold axis. The coiled-coil domain is divided into three segments that are separated by insertion loops. The C-terminal domain, which consists of 30 residues from each subunit, contains a beta-propeller-like structure with a hydrophobic interior.

CONCLUSIONS

The residues within the C-terminal domain make extensive hydrophobic and some polar intersubunit interactions. This is consistent with the C-terminal domain being important for the correct assembly of fibritin, as shown earlier by mutational studies. Tight interactions between the C-terminal residues of adjacent subunits counteract the latent instability that is suggested by the structural properties of the coiled-coil segments. Trimerization is likely to begin with the formation of the C-terminal domain which subsequently initiates the assembly of the coiled coil. The interplay between the stabilizing effect of the C-terminal domain and the labile coiled-coil domain may be essential for the fibritin function and for the correct functioning of many other alpha-fibrous proteins.

Osteoporosis in china

SUMMARY

Based on related studies published between 1980 and May 2008, we examine the prevalence of osteoporoses in mainland China, Hong Kong, and Taiwan. Overall, the prevalence of osteoporosis among these Chinese populations remains low compared to other Caucasian populations; in the mainland, it was approximately 13%.

INTRODUCTION

Osteoporosis is a significant public health problem and has received great attention in industrialized countries. However, limited is known in many developing countries including China, where aging and changing lifestyles likely contribute to increased osteoporosis. The objectives of the study is to examine the disease burden (prevalence) and time trends of osteoporosis in mainland China, Hong Kong, and Taiwan.

METHODS

Related studies published in English and Chinese between January 1980 and May 2008 were reviewed and analyzed.

RESULTS

The prevalence increased with age and varied dramatically based on local versus international diagnosis criteria. In the mainland, reported overall prevalence of osteoporosis based on nationwide surveys ranged from 6.6% to 19.3% (average = 13.0%). The prevalence varied considerably across studies, and by regions, gender, and bone sites, but the urban to rural difference was small. In Hong Kong, the prevalence among women > or =50 years ranged from 34.1-37% in the spine; was 7% in the same aged men. In Taiwan, among those aged > or =50 years, average prevalence of osteoporosis was 11.4% in women and 1.6% in men.

CONCLUSIONS

Future national programs need to monitor the burden of osteoporosis in China though available data indicate that the prevalence of osteoporosis remains low compared to that of other Caucasian populations.

Randomized trial of breast self-examination in Shanghai: methodology and preliminary results

BACKGROUND

The efficacy of breast self-examination in helping to reduce mortality from breast cancer has not been rigorously demonstrated.

PURPOSE

To assess efficacy, a large, randomized trial was initiated in Shanghai, China.

METHODS

From October 1989 to October 1991, 267040 current and retired female employees associated with 520 factories in the Shanghai Textile Industry Bureau were randomly assigned on the basis of factory to either a self-examination instruction group (133375 women) or a control group (133665 women). The women were born within the period from 1925 through 1958. Women in the instruction group were given intensive training in breast self-examination, including the use of silicone breast models and personalized instruction, plus two subsequent reinforcement sessions and multiple reminders to practice the technique. Women in the control group were asked to attend training sessions on the prevention of low back pain. All women have been followed for the development of breast diseases and for death from breast cancer.

RESULTS

A high level of participation during the first 4-5 years of the trial was documented among women in the instruction group. Randomly sampled women in this group demonstrated greater proficiency in detecting lumps in breast models than did randomly sampled women in the control group. Approximately equal numbers of breast cancers were detected in the two groups (331 in the instruction group and 322 in the control group) through 1994, which is the last year for which case-finding efforts have been completed. The breast cancers detected in the instruction group were not diagnosed at an appreciably earlier stage or smaller size than those in the control group. More benign breast lesions were detected in the instruction group than in the control group (1457 versus 623, respectively), suggesting a higher index of suspicion for women who received training. Cumulative breast cancer mortality rates through 5 years from entry into the study were nearly equivalent for the two groups.

CONCLUSIONS

Breast self-examination has not led to a reduction in mortality from breast cancer in this study cohort in the first several years since the trial began. A shift toward the diagnosis of disease at a less advanced stage in women given instruction has also not been demonstrated. Longer follow-up of participants in this trial is required before final assessment can be made of the efficacy of breast self-examination.

IMPLICATIONS

At this time, there is insufficient evidence to recommend for or against the teaching of breast self-examination.

Sex-ratio segregation distortion associated with reproductive isolation in Drosophila

Sex-ratio distortion is the most common form of non-Mendelian segregation observed in natural populations. It may occur even more frequently than direct observations suggest, because the dysgenic population consequences of a biased sex ratio are expected to result in the rapid evolution of suppressors, resulting in suppressed or "cryptic" segregation distortion. Here we report evidence for cryptic sex-ratio distortion that was discovered by introgressing segments of the genome of Drosophila mauritiana into the genome of Drosophila simulans. The autosomal suppressor of sex-ratio distortion, which is also associated with a reduction in hybrid male fertility, has been genetically localized to a region smaller than 80-kb pairs in chromosome 3.

Pain and depression in patients with newly diagnosed pancreas cancer

PURPOSE

To evaluate the prevalence of pain and depression, their correlation, and their effect on quality of life in patients with recently diagnosed adenocarcinoma of the pancreas (PC).

MATERIALS AND METHODS

Cross-sectional pain and psychosocial distress were assessed using validated instruments, including the Memorial Pain Assessment Card (MPAC), Beck Depression Inventory (BDI), Hopelessness Scale (BHS), and Functional Living Index-Cancer (FLIC). Patients were evaluated before their first operation for PC or first treatment with chemotherapy at a large tertiary-care cancer center.

RESULTS

One hundred thirty patients with proven PC were studied: 83 before their operation and 47 before their first chemotherapy treatment. At the time of study entrance, 37% of patients had no pain and an additional 34% had pain that was mild or less severe. Only 29% of patients had moderate, strong, or severe pain. Chemotherapy patients reported significantly more intense pain than did preoperative patients (P = .02). Symptoms of depression were assessed using the BDI and BHS scales. A substantial minority of patients (38%) had BDI scores > or = 15, which suggests high levels of depressive symptoms. There was a significant correlation between increasing pain and depressive symptoms among those who experienced pain. Quality of life was assessed using the Weekly Activity Checklist (WAC) and the FLIC. Compared with patients who had no pain or mild pain, patients with moderate or greater pain had significantly impaired functional activity (P = .03) and poorer quality-of-life scores (P = .02) when compared with those with lesser degrees of pain. There were significant correlations between increasing pain and depression and between pain and depressive symptoms and impaired quality of life and function.

CONCLUSION

Our results indicate that moderate or severe pain and symptoms of depression are not as prevalent in recently diagnosed PC patients as is generally believed. However, one third have inadequate pain control despite the use of oral analgesics. These patients can be identified by the use of a simple self-report instrument (the MPAC card). Quality of life and function are adversely affected by moderate or greater levels of perceived pain intensity. A simple and rapid assessment is possible and can identify high-risk patients in need of intervention that may improve quality of life.

NF-kappaB functions as both a proapoptotic and antiapoptotic regulatory factor within a single cell type

Recently NF-kappaB has been shown to have both proapoptotic and antiapoptotic functions. In T cell hybridomas, both T cell activators and glucocorticoids induce apoptosis. Here we show that blockade of NF-kappaB activity, using a dominant negative IkappaBalpha, has opposite effects on these two apoptotic signals. Treatment with PMA plus ionomycin (P/I) results in the upregulation of Fas Ligand (FasL) and induction of apoptosis. Inhibition of NF-kappaB activity inhibits the P/I mediated induction of FasL mRNA and decreases the level of apoptosis in these cultures, thus establishing NF-kappaB as a proapoptotic factor in this context. Conversely, inhibition of NF-kappaB confers a tenfold increase in glucocorticoid mediated apoptosis, establishing that NF-kappaB also functions as an antiapoptotic factor. We conclude that NF-kappaB is a context-dependent apoptosis regulator. Our data suggests that NF-kappaB may function as an antiapoptotic factor in thymocytes while functioning as a proapoptotic factor in mature peripheral T cells.

Quantitation of RNA polymerase II and its transcription factors in an HeLa cell: little soluble holoenzyme but significant amounts of polymerases attached to the nuclear substructure

Various complexes that contain the core subunits of RNA polymerase II associated with different transcription factors have been isolated from eukaryotes; their precise molecular constitution depends on the purification procedure. We estimated the numbers of various components of such complexes in an HeLa cell by quantitative immunoblotting. The cells were lysed with saponin in a physiological buffer; approximately 140,000 unengaged polymerases (mainly of form IIA) were released. Only approximately 4,000 of these soluble molecules sedimented in glycerol gradients as holoenzyme-sized complexes. About 180,000 molecules of polymerases (approximately 110,000 molecules of form IIO) and 10,000 to 30,000 molecules of each of TFIIB, TFIIEalpha, TFIIEbeta, TFIIF-RAP74, TFIIF-RAP30, and TFIIH-MAT1 remained tightly associated with the nuclear substructure. Most proteins and run-on activity were retained when approximately 50% of the chromatin was detached with a nuclease, but approximately 45,000 molecules of bound TATA binding protein (TBP) were detached. Similar results were obtained after cross-linking living cells with formaldehyde. The results provide little support for the existence of a large pool of soluble holoenzyme; they are consistent with TBP-promoter complexes in nuclease-sensitive chromatin being assembled into preinitiation complexes attached to the underlying structure.

A randomized trial of induction docetaxel-cisplatin-5FU followed by concomitant cisplatin-RT versus concomitant cisplatin-RT in nasopharyngeal carcinoma (GORTEC 2006-02)

Background

Concomitant chemotherapy (CT)-radiotherapy (RT) is a standard of care in locally advanced nasopharyngeal carcinoma (NPC) and a role for induction CT is not established.

Methods

Patients with locally advanced NPC, WHO type 2 or 3, were randomized to induction TPF plus concomitant cisplatin-RT or concomitant cisplatin-RT alone. The TPF regimen consisted of three cycles of Docetaxel 75 mg/m2 day 1; cisplatin 75 mg/m2 day 1; 5FU 750 mg/m2/day days 1-5. RT consisted of 70 Gy in 7 weeks plus concomitant cisplatin 40 mg/m2 weekly.

Results

A total of 83 patients were included in the study. Demographics and tumour characteristics were well balanced between both arms. Most of the patients (95%) in the TPF arm received three cycles of induction CT. The rate of grade 3-4 toxicity and the compliance (NCI-CTCAE v3) during cisplatin-RT were not different between both arms. With a median follow-up of 43.1 months, the 3-year PFS rate was 73.9% in the TPF arm versus 57.2% in the reference arm [hazard ratio (HR) = 0.44; 95% confidence interval (CI): 0.20-0.97, P = 0.042]. Similarly the 3 years overall survival rate was 86.3% in the TPF arm versus 68.9% in the reference arm (HR = 0.40; 95% CI: 0.15-1.04, P = 0.05).

Conclusion

In conclusion, several important aspects can be emphasized: the compliance to induction TPF was good and TPF did not compromise the tolerance of the concomitant RT-cisplatin phase. The improved PFS and overall survival rates needs to be confirmed by further trials.

Subunit composition determines E2F DNA-binding site specificity

The product of the retinoblastoma (Rb) susceptibility gene, Rb-1, regulates the activity of a wide variety of transcription factors, such as E2F, in a cell cycle-dependent fashion. E2F is a heterodimeric transcription factor composed of two subunits each encoded by one of two related gene families, denoted E2F and DP. Five E2F genes, E2F-1 through E2F-5, and two DP genes, DP-1 and DP-2, have been isolated from mammals, and heterodimeric complexes of these proteins are expressed in most, if not all, vertebrate cells. It is not yet clear whether E2F/DP complexes regulate overlapping and/or specific cellular genes. Moreover, little is known about whether Rb regulates all or a subset of E2F-dependent genes. Using recombinant E2F, DP, and Rb proteins prepared in baculovirus-infected cells and a repetitive immunoprecipitation-PCR procedure (CASTing), we have identified consensus DNA-binding sites for E2F-1/DP-1, E2F-1/DP-2, E2F-4/DP-1, and E2F-4/DP-2 complexes as well as an Rb/E2F-1/DP-1 trimeric complex. Our data indicate that (i) E2F, DP, and Rb proteins each influence the selection of E2F-binding sites; (ii) E2F sites differ with respect to their intrinsic DNA-bending properties; (iii) E2F/DP complexes induce distinct degrees of DNA bending; and (iv) complex-specific E2F sites selected in vitro function distinctly as regulators of cell cycle-dependent transcription in vivo. These data indicate that the specific sequence of an E2F site may determine its role in transcriptional regulation and suggest that Rb/E2F complexes may regulate subsets of E2F-dependent cellular genes.

Pain as a predictor of outcome in patients with operable pancreatic carcinoma

BACKGROUND

The purpose of our study was to evaluate the relationship between pain and resectability and survival in patients with operable pancreatic carcinoma.

METHODS

Pain, pain intensity, and pain location were prospectively assessed in newly diagnosed patients with operable adenocarcinoma of the pancreas. Patients were evaluated before their first operation at a large tertiary care cancer center. Pain factors were then correlated with outcomes of surgery, including resectability and survival.

RESULTS

Seventy-seven patients with operable pancreatic carcinoma were evaluated before operation. With the Memorial Pain Assessment Card and a demographic questionnaire, an analysis of analgesic use and pain prevalence and intensity were quantitated. Twenty-two (29%) of 77 patients reported no pain. Fifty-five had mild to severe pain. Moderately severe or greater pain (Memorial Pain Assessment Card Tursky scores of 5 or greater or visual analogue self-assessment pain intensity scores greater than 30) was found in 20 patients. Twenty-six (34%) patients had resectable disease. Of the 51 patients who did not have resections, 35 had metastatic disease. Locoregional unresectable disease without metastases was found in 16 patients. Resectability was correlated with the presence of pain (p = 0.04). The median survival for all patients was 6.7 months. Not surprisingly, patients undergoing resection had a significantly better median survival than did those whose disease was unresectable (5.5 versus 15.1 months). Pain before operation significantly predicted survival (median survival for those with pain, 5.7 months; for those without pain, 15 months; p = 0.003). Even among patients who underwent resection, the presence of pain was associated with a worse survival (21.9 months versus 9.2 months; p = 0.045). In a multivariate analysis the two significant variables were inability to undergo resection and presence of any pain.

CONCLUSIONS

The presence of pain in newly diagnosed patients with potentially operable pancreatic cancer is an ominous predictor of resectability and of survival. Even if the patient can undergo resection, the presence of preoperative pain is associated with a poor prognosis. Patients with operable pancreatic cancer who present with pain, even those whose evaluation shows a likelihood of resectability, are at high risk for recurrence with an impaired survival compared with those patients without pain.

Necroptosis inhibitor necrostatin-1 promotes cell protection and physiological function in traumatic spinal cord injury

Spinal cord injury (SCI) is a common and serious trauma which lacks efficient treatment. Inhibition of cell death in the trauma area is important for spinal cord protection during this process. In this study, necroptosis inhibitor necrostatin-1 (Nec-1) was used to treat SCI rats, to investigate the role of Nec-1 in the recovery of SCI. Nec-1 was found to reduce lesions, cytokines and reactive oxygen species (ROS), improve pathological conditions and blood supply in the spinal cord trauma area. Further study indicated that Nec-1 could inhibit necroptosis by inhibiting RIP1/3-MLKL recruitment and inhibit apoptosis by inhibiting Caspase 3 and Bax while activating Bcl-2. Ethological performance of SCI rats confirmed improvement and protection of physiological function by Nec-1. Nec-1 as a potential treatment for SCI warrants further study. To our knowledge, this is the first study on the role of Nec-1 in the treatment of traumatic SCI. Our research also found inhibition effects of Nec-1 on apoptosis, not only necroptosis - as reported by most publications.

Effects of garlic thioallyl derivatives on growth, glutathione concentration, and polyamine formation of human prostate carcinoma cells in culture

This study investigated whether naturally occurring garlic derivatives and synthetic S-cysteinyl compounds that resemble garlic constituents have antiproliferative effects on human prostate carcinoma (LNCaP) cells. Studies also examined whether S-allylmercaptocysteine and S-allylcysteine affect two important molecular targets, namely reduced glutathione and polyamines. Results showed that S-allylmercaptocysteine (50 mg/L) diminished LNCaP cell growth whereas the antiproliferative effect of S-allylcysteine was not as pronounced. Studies using synthetic S-cysteinyl analogues revealed that growth inhibition was most effective with compounds containing a disulfide or an active diallyl moiety. Marginal to no inhibitory effect was observed with monosulfinic analogues. Both S-allylmercaptocysteine and S-allylcysteine caused an increase in LNCaP cell reduced glutathione concentrations. Putrescine and spermine concentrations decreased and spermidine increased 3 d after S-allylmercaptocysteine treatment. At 5 d after S-allylmercaptocysteine treatment, polyamine concentrations were similar to those of saline-treated controls. Diminished cell growth and altered polyamine concentrations suggest that S-allylmercaptocysteine may impede the polyamine synthesizing enzyme, ornithine decarboxylase, either by enhancing the formation of reduced glutathione, a known inhibitor of ornithine decarboxylase, or by reacting directly with ornithine decarboxylase at its nucleophilic thiol moiety. Because S-allylcysteine also increases reduced glutathione formation but does not significantly inhibit growth, the latter mechanism may be more likely for this compound. These data provide further evidence that nonessential nutrients derived from garlic may modulate tumor growth. Further research is required on effects of garlic derivatives in vivo before information from the present studies can be used to assist in the development of effective nutritional strategies for preventing progression of prostate cancer.

Phase I clinical and pharmacology study of topotecan given daily for 5 consecutive days to patients with advanced solid tumors, with attempt at dose intensification using recombinant granulocyte colony-stimulating factor

BACKGROUND

Topotecan has been shown in previous studies to be a specific inhibitor of topoisomerase I, a nuclear enzyme required for DNA replication and transcription.

PURPOSE

Our objectives in this phase I clinical trial were to determine the maximum tolerated dose, dose-limiting toxic effects, and recommended phase II dose of topotecan and to define the pharmacokinetics of topotecan in humans.

METHODS

Forty-three patients with advanced, incurable solid tumors were treated. Doses ranged from 0.5 to 2.0 mg/m2 daily for five days [corrected], with treatment cycles repeated initially every 28 days. Following the identification of the standard maximum tolerated dose, further dose escalations were attempted by following topotecan cycles with recombinant granulocyte colony-stimulating factor (rG-CSF).

RESULTS

The maximum tolerated dose without rG-CSF for patients without prior cytotoxic therapy was 1.75 mg/m2 daily. The maximum tolerated dose for previously treated patients was 1.50 mg/m2 daily. The dose-limiting toxic effect was myelosuppression, with granulocytopenia being most commonly observed. Use of rG-CSF did not permit topotecan dose intensification, since thrombocytopenia and fatigue rapidly emerged as dose-limiting toxic effects. Plasma half-lives of topotecan (lactone form) were approximately 10 and 100 minutes for distribution and elimination phases, respectively.

CONCLUSIONS

The doses of topotecan recommended for use in phase II clinical trials in solid tumors are 1.5 and 1.25 mg/m2 daily in previously untreated and previously treated patients, respectively. Based on observed rates of recovery from myelosuppression, treatment should be possible on a 21-day cycle. Dose intensification was not possible with the use of rG-CSF; however, rG-CSF may be a useful addition to the regimens of those few patients who experience either prolonged granulocytopenia or neutropenic sepsis or those who are not able to receive their second treatment cycle by day 21.

Transcription activation via enhanced preinitiation complex assembly in a human cell-free system lacking TAFIIs

In contrast to previous findings in cell-free systems reconstituted with partially purified metazoan factors, we demonstrate dramatic activation of transcription in a TBP-dependent but TAFII-independent manner in HeLa nuclear extracts immunodepleted of TBP and major TAFIIs. Single-round transcription assays reveal that TAFII-independent activation is manifested at the level of productive preinitiation complex formation and that TAFIIs actually impair functional preinitiation complex assembly in a core promoter-specific manner. Furthermore, TAFIIs appear to elevate absolute levels of transcription under multiple-round transcription conditions, presumably by facilitating secondary initiation events. Finally, human coactivator activities related to those in yeast RNA polymerase II/mediator complexes appear to function in unfractionated HeLa nuclear extracts.

Genetic factors related to racial variation in plasma levels of insulin-like growth factor-1: implications for premenopausal breast cancer risk

The oral contraceptive pill is associated with a modest increase in the risk of early-onset breast cancer in the general population, but it is possible that the risk is higher in certain subgroups of women. The relative risk of breast cancer associated with oral contraceptive use has been reported to be higher for African-American women than for white women. African-American women also have a higher incidence of premenopausal breast cancer than white women. Circulating levels of insulin-like growth factor-1 (IGF-I) vary between ethnic groups and are positively associated with the risk of premenopausal breast cancer. In general, the plasma level of IGF-I is lower in women who take oral contraceptives than in women who do not. In an attempt to explain the observed ethnic difference in IGF-I levels with oral contraceptive use, we sought to identify polymorphic variants of genes that are associated with IGF-I levels and estrogen metabolism. We measured IGF-I and IGFBP-3 plasma levels in 503 nulligravid women between the ages of 17 and 35. All women filled out a questionnaire that included information about ethnic background and oral contraceptive use. Samples of DNA were used to genotype the women for known polymorphic variants in the IGF1, AIB1, and CYP3A4 genes. Black women had significantly higher mean IGF-I levels than white women (330 ng/ml versus 284 ng/ml; P = 0.001, adjusted for age and oral contraceptive use). IGF-I levels were significantly suppressed by oral contraceptives in white women (301 ng/ml versus 267 ng/ml; P = 0.0003), but not in black women. Among oral contraceptive users, the IGF-I level was positively associated with the absence of the IGF1 19-repeat allele (338 ng/ml versus 265 ng/ml; P = 0.00007), with the presence of the CYP3A4 variant allele (320 ng/ml versus 269 ng/ml; P = 0.01), and with the presence of the AIB1 26-repeat allele (291 ng/ml versus 271; P = 0.08). After adjusting for genotypes, ethnic group was no longer a significant predictor of the IGF-I level. IGF-I levels are higher among black than white women. Polymorphic variants in the CYP3A4, IGF1, and AIB1 genes are associated with increases in the plasma levels of IGF-I among oral contraceptive users and the variant alleles are much more common in black women than in white women. The high incidence of premenopausal breast cancer among black women may be mediated through genetic modifiers of circulating levels of IGF-I.

Neurogenesis in neonatal rat brain is regulated by peripheral injection of basic fibroblast growth factor (bFGF)

Many major diseases of human brain involve deficiencies of select neuronal populations. As one approach to repair, we examined regulation of neurogenesis directly in vivo, employing postnatal day 1 (P1) cerebellar cortex, which is composed primarily of granule neurons and dividing precursors. We focused on basic fibroblast growth factor (bFGF), which stimulates precursor mitosis in culture and which is highly expressed in cerebellum during neurogenesis. Subcutaneous injection of bFGF increased [3H]thymidine ([3H]dT) incorporation, a marker for DNA synthesis, by 50% in whole cerebellar homogenates, suggesting that peripherally administered factor altered ongoing neural proliferation. Further, assay of isolated granule precursors revealed a 4-fold increase in [3H]dT incorporation following in vivo bFGF treatment, indicating that granule neuroblasts were the major bFGF-responsive population. Morphologic analysis indicated that twice as many granule precursors were in S-phase of the mitotic cycle after peripheral bFGF. To determine whether other neurogenetic populations respond to peripheral bFGF, we examined additional brain regions in vivo. bFGF stimulated DNA synthesis by 68% in hippocampus, and by > 250% in pontine subventricular zone (SVZ). In contrast, incorporation was not altered in basal pons or cerebral cortex, regions in which neurogenesis has already ceased. To define potential direct actions of peripherally administered factor, 125I-bFGF was used to study distribution. Intact 18 kDa 125I-bFGF was recovered from brain following peripheral injection, suggesting that the factor acted directly to stimulate mitosis in dividing neuroblasts. The stimulation of neuronal proliferation by exogenous bFGF suggests that the factor normally regulates neurogenesis, and provides new therapeutic approaches to promote functional recovery from nervous system diseases.