Pilot study assessing gut microbial diversity among sexual and gender minority young adults.

Evidence supports that people identifying as a sexual or gender minority (SGMs) experience minority-related stress resulting from discrimination or expectations of prejudice, and that this is associated with increased mental and physical health problems compared to cisgender heterosexuals. However, the biological mechanisms driving minority-related stress impacts remain unknown, including the role of the gut microbiome. Thus, the aim of this study was to determine the relationship between SGM status and gut microbiome health among young adults attending a 4-year university. To this end, a prospective pilot study was completed in the fall and spring semesters of 2021-22. Self-identified SGMs (N = 22) and cisgender-heterosexuals (CIS-HET, N = 43) completed in-person interviews to provide mental health data and demographic information. Nail and saliva samples were collected at the time of interview to quantify chronic and acute cortisol. Stool samples were collected within 48 hours of interview for microbiome analysis. Assessment of the gut microbiota identified a significant reduction in alpha diversity among the SGM group, even when adjusting for mental health outcome. SGM group showed trends for higher abundance of microbes in phylum Bacteroidetes and lower abundance of microbes in phyla Firmicutes, Actinobacteria, and Proteobacteria compared to the CIS-HET group. These findings support that the gut microbiome could be contributing to negative health effects among the SGM community.

Appendectomy: a risk factor for colectomy in patients with Clostridium difficile.

BACKGROUND: The appendix, considered an intestinal microbiota reservoir, may be protective against the risk of fulminant Clostridium difficile infection. METHODS: Retrospective analysis was performed in patients with C. difficile infection at St. Francis Medical Center from 2007 to 2011. Outcome of infection and history of appendectomy were compared. Statistical analysis was by chi-square and multivariate logistic regression. RESULTS: In total, 507 patients were hospitalized for C. difficile. Of 388 patients with intact appendix, 20 (5.2%) developed fulminant infection and required colectomy, whereas of 119 patients with previous appendectomy, 13 (10.9%) required colectomy. An increased severity of disease, indicated by increased rate of colectomy, occurred for the group with a history of appendectomy (P = .03). Age and sex were adjusted by multivariant regression (P = .05). CONCLUSIONS: Appendectomy may be a risk factor for increased severity of C. difficile infection. Although the mechanism is unknown, further studies are warranted.

Bilateral and unilateral stenting for malignant hilar obstruction: a systematic review and meta-analysis.

BACKGROUND: Stents are used for palliating inoperable malignant bile duct hilar obstruction. It is not clear if bilateral stenting provides any advantage over unilateral stenting in these patients. Compare bilateral and unilateral stenting in malignant hilar obstruction. STUDY SELECTION CRITERIA: Studies using stents for palliation in patients with malignant hilar obstruction were selected. DATA COLLECTION AND EXTRACTION: Articles were searched in MEDLINE, PubMed, Ovid journals, CINAH, International Pharmaceutical Abstracts, OLDMEDLINE, MEDLINE nonindexed citations, and Cochrane Central Register of Controlled Trials and Database of Systematic Reviews. Two reviewers independently searched and extracted data. Any differences were resolved by mutual agreement. STATISTICAL METHODS: Pooled proportions were calculated using both the Mantel-Haenszel method (fixed effects model) and DerSimonian-Laird method (random effects model). The heterogeneity among studies was tested using Cochran's Q test based upon inverse variance weights. The initial search identified 1,640 reference articles, of which 169 were selected and reviewed. Thirteen studies (n = 340) for bilateral metallic stents, eight studies (n = 575) for unilateral metallic stents, eight studies (n = 367) for bilateral plastic stenting, and seven studies (n = 850) for unilateral plastic stenting which met the inclusion criteria were included in this analysis. Pooled data are shown in Tables 1 and 2. The pooled estimates by the fixed and random effect models were similar. The p for chi-squared heterogeneity for all the pooled accuracy estimates was >0.10. Bilateral metal stenting seems to have lower odds of overall complications when compared to unilateral metallic stenting. Bilateral metal stents seem to have higher odds of lowering bilirubin than unilateral metal stents, but the 30-day mortality was no different. For metal stents, bilateral metal stents are superior in palliating symptoms due to hyperbilirubinemia. Unilateral plastic stenting seems to have similar odds of overall complications, cholangitis, and 30-day mortality when compared to bilateral plastic stenting for malignant hilar strictures. In patients with malignant hilar stricture, unilateral plastic stenting is comparable to bilateral plastic stenting for adverse events.

Multifunctional roles of urokinase plasminogen activator (uPA) in cancer stemness and chemoresistance of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is almost always lethal. One of the underlying reasons for this lethality is believed to be the presence of cancer stem cells (CSC), which impart chemoresistance and promote recurrence, but the mechanisms responsible are unclear. Recently the poor prognosis of PDAC has been correlated with increased expression of urokinase plasminogen activator (uPA). In the present study we examine the role of uPA in the generation of PDAC CSC. We observe a subset of cells identifiable as a side population (SP) when sorted by flow cytometry of MIA PaCa-2 and PANC-1 pancreatic cancer cells that possess the properties of CSC. A large fraction of these SP cells are CD44 and CD24 positive, are gemcitabine resistant, possess sphere-forming ability, and exhibit increased tumorigenicity, known characteristics of cancer stemness. Increased tumorigenicity and gemcitabine resistance decrease after suppression of uPA. We observe that uPA interacts directly with transcription factors LIM homeobox-2 (Lhx2), homeobox transcription factor A5 (HOXA5), and Hey to possibly promote cancer stemness. uPA regulates Lhx2 expression by suppressing expression of miR-124 and p53 expression by repressing its promoter by inactivating HOXA5. These results demonstrate that regulation of gene transcription by uPA contributes to cancer stemness and clinical lethality.

Diagnostic accuracy of endoscopic ultrasound in pancreatic neuroendocrine tumors: a systematic review and meta analysis.

AIM: To detect pancreatic neuroendocrine tumors (PNETs) has been varied. This study is undertaken to evaluate the accuracy of endoscopic ultrasound (EUS) in detecting PNETs. METHODS: Only EUS studies confirmed by surgery or appropriate follow-up were selected. Articles were searched in Medline, Ovid journals, Medline nonindexed citations, and Cochrane Central Register of Controlled Trials and Database of Systematic Reviews. Pooling was conducted by both fixed and random effects model). RESULTS: Initial search identified 2610 reference articles, of these 140 relevant articles were selected and reviewed. Data was extracted from 13 studies (n = 456) which met the inclusion criteria. Pooled sensitivity of EUS in detecting a PNETs was 87.2% (95%CI: 82.2-91.2). EUS had a pooled specificity of 98.0% (95%CI: 94.3-99.6). The positive likelihood ratio of EUS was 11.1 (95%CI: 5.34-22.8) and negative likelihood ratio was 0.17 (95%CI: 0.13-0.24). The diagnostic odds ratio, the odds of having anatomic PNETs in positive as compared to negative EUS studies was 94.7 (95%CI: 37.9-236.1). Begg-Mazumdar bias indicator for publication bias gave a Kendall's tau value of 0.31 (P = 0.16), indication no publication bias. The P for χ² heterogeneity for all the pooled accuracy estimates was > 0.10. CONCLUSION: EUS has excellent sensitivity and specificity to detect PNETs. EUS should be strongly considered for evaluation of PNETs.

Updated analysis of SWOG-directed intergroup study 0116: a phase III trial of adjuvant radiochemotherapy versus observation after curative gastric cancer resection.

PURPOSE: Surgical resection of gastric cancer has produced suboptimal survival despite multiple randomized trials that used postoperative chemotherapy or more aggressive surgical procedures. We performed a randomized phase III trial of postoperative radiochemotherapy in those at moderate risk of locoregional failure (LRF) following surgery. We originally reported results with 4-year median follow-up. This update, with a more than 10-year median follow-up, presents data on failure patterns and second malignancies and explores selected subset analyses. PATIENTS AND METHODS: In all, 559 patients with primaries ≥ T3 and/or node-positive gastric cancer were randomly assigned to observation versus radiochemotherapy after R0 resection. Fluorouracil and leucovorin were administered before, during, and after radiotherapy. Radiotherapy was given to all LRF sites to a dose of 45 Gy. RESULTS: Overall survival (OS) and relapse-free survival (RFS) data demonstrate continued strong benefit from postoperative radiochemotherapy. The hazard ratio (HR) for OS is 1.32 (95% CI, 1.10 to 1.60; P = .0046). The HR for RFS is 1.51 (95% CI, 1.25 to 1.83; P < .001). Adjuvant radiochemotherapy produced substantial reduction in both overall relapse and locoregional relapse. Second malignancies were observed in 21 patients with radiotherapy versus eight with observation (P = .21). Subset analyses show robust treatment benefit in most subsets, with the exception of patients with diffuse histology who exhibited minimal nonsignificant treatment effect. CONCLUSION: Intergroup 0116 (INT-0116) demonstrates strong persistent benefit from adjuvant radiochemotherapy. Toxicities, including second malignancies, appear acceptable, given the magnitude of RFS and OS improvement. LRF reduction may account for the majority of overall relapse reduction. Adjuvant radiochemotherapy remains a rational standard therapy for curatively resected gastric cancer with primaries T3 or greater and/or positive nodes.

N-cadherin mediates angiogenesis by regulating monocyte chemoattractant protein-1 expression via PI3K/Akt signaling in prostate cancer cells.

Over the past decade, evidence continues to mount showing that N-cadherin is a critical protein in cancer progression and metastasis. In the present study, we evaluated the expression of N-cadherin in human prostate cancer tissue specimens and cell lines. Enhanced expression of N-cadherin was observed in both the malignant and bone-metastasized prostate tissue specimens compared to the healthy prostate tissues. Consistent with the tissue array data, N-cadherin was highly expressed in PC3, but not in Du145 and LNCaP human prostate cell lines. Based on cell to cell binding assay, we found that N-cadherin expression facilitates homotypic interaction between human prostate cancer cells and human microvascular endothelial cells (HMEC). Human angiogenesis antibody array and in vitro angiogenesis assay showed that siRNA-mediated knockdown of N-cadherin reduced the secretion of monocyte chemoattractant protein-1 (MCP-1), which played a potential role in stimulating capillary network formation of HMEC. Additionally, culture supernatant of Du145 cells transfected with full-length N-cadherin expressing plasmid showed increased MCP-1 expression and chemoattractant ability compared to normal Du145 cells. Further, we noticed that blocking PI3K activity inhibited N-cadherin mediated MCP-1 expression. Our data demonstrated that N-cadherin in prostate cancer cell mediates cell-cell adhesion and regulates MCP-1 expression via the PI3K/Akt signaling pathway.

Localization of uPAR and MMP-9 in lipid rafts is critical for migration, invasion and angiogenesis in human breast cancer cells.

BACKGROUND: uPAR and MMP-9, which play critical roles in tumor cell invasion, migration and angiogenesis, have been shown to be associated with lipid rafts. METHODS: To investigate whether cholesterol could regulate uPAR and MMP-9 in breast carcinoma, we used MßCD (methyl beta cyclodextrin, which extracts cholesterol from lipid rafts) to disrupt lipid rafts and studied its effect on breast cancer cell migration, invasion, angiogenesis and signaling. RESULTS: Morphological evidence showed the association of uPAR with lipid rafts in breast carcinoma cells. MßCD treatment significantly reduced the colocalization of uPAR and MMP-9 with lipid raft markers and also significantly reduced uPAR and MMP-9 at both the protein and mRNA levels. Spheroid migration and invasion assays showed inhibition of breast carcinoma cell migration and invasion after MßCD treatment. In vitro angiogenesis studies showed a significant decrease in the angiogenic potential of cells pretreated with MßCD. MßCD treatment significantly reduced the levels of MMP-9 and uPAR in raft fractions of MDA-MB-231 and ZR 751 cells. Phosphorylated forms of Src, FAK, Cav, Akt and ERK were significantly inhibited upon MßCD treatment. Increased levels of soluble uPAR were observed upon MßCD treatment. Cholesterol supplementation restored uPAR expression to basal levels in breast carcinoma cell lines. Increased colocalization of uPAR with the lysosomal marker LAMP1 was observed in MßCD-treated cells when compared with untreated cells. CONCLUSION: Taken together, our results suggest that cholesterol levels in lipid rafts are critical for the migration, invasion, and angiogenesis of breast carcinoma cells and could be a critical regulatory factor in these cancer cell processes mediated by uPAR and MMP-9.

Further reduction of hospital stay for laparoscopic colon resection by modifications of the fast-track care plan.

BACKGROUND: Fast-track surgery has been described as a plan to facilitate early recovery. We present one surgeon's modifications to fast-track surgery for laparoscopic colectomy patients. METHODS: We performed a retrospective review of 48 consecutive patients undergoing elective laparoscopic colectomy treated by a modified fast-track plan between 2004 and 2008. Elements included preoperative education, pre-anesthesia dexamethasone, immediate postoperative general diet, no urinary catheter, no epidural anesthesia, and no flatus or bowel movement as a discharge requirement. Data collected included the following: age, sex, body mass index, resection indications, surgical time, blood loss, pain score, time to ambulation, time to bowel function, length of stay, complications, and mortality. RESULTS: The mean length of stay was 37 hours (1.5 d), with 29 of 48 patients discharged without passage of flatus or stool. Only 1 patient required readmission. CONCLUSIONS: Our modified fast-track plan achieved significant improvement in length of stay for laparoscopic colectomy compared with previous results.

Small interfering RNA-directed knockdown of uracil DNA glycosylase induces apoptosis and sensitizes human prostate cancer cells to genotoxic stress.

Uracil DNA glycosylase (UNG) is the primary enzyme responsible for removing uracil residues from DNA. Although a substantial body of evidence suggests that DNA damage plays a role in cancer cell apoptosis, the underlying mechanisms are poorly understood. In particular, very little is known about the role of base excision repair of misincorporated uracil in cell survival. To test the hypothesis that the repair of DNA damage associated with uracil misincorporation is critical for cancer cell survival, we used small interfering RNA (siRNA) to target the human UNG gene. In a dose-dependent and time-dependent manner, siRNA specifically inhibited UNG expression and modified the expression of several genes at both mRNA and protein levels. In LNCaP cells, p53, p21, and Bax protein levels increased, whereas Bcl2 levels decreased. In DU145 cells, p21 levels were elevated, although mutant p53 and Bax levels remained unchanged. In PC3 cells, UNG inhibition resulted in elevated p21 and Bax levels. In all three cell lines, UNG inhibition reduced cell proliferation, induced apoptosis, and increased cellular sensitivity to genotoxic stress. Furthermore, an in vitro cleavage experiment using uracil-containing double-stranded DNA as a template has shown that siRNA-mediated knockdown of UNG expression significantly reduced the uracil-excising activity of UNG in human prostate cancer cells, which was associated with DNA damage analyzed by comet assay. Taken together, these findings indicate that RNA interference-directed targeting of UNG is a convenient, novel tool for studying the biological role of UNG and raises the potential of its application for prostate cancer therapy.

Stat3-siRNA induces Fas-mediated apoptosis in vitro and in vivo in breast cancer.

Stat3, a member of the signal transducer and activator of transcription family, has the potential to mediate cell survival, growth and differentiation. Stat3 is constitutively activated in numerous cancers, including >50% of breast cancers. Previous studies demonstrated that constitutively activated Stat3 plays an important role in breast cancer development and progression by promoting cell proliferation and inhibiting apoptosis. The present study was designed to investigate the potential use of RNA interference (RNAi) to block Stat3 expression and activation, as well as the subsequent effect on human breast cancer cell growth. Our studies show that knockdown of STAT3 expression by siRNA reduced expression of Bcl-xL and survivin in MDA-MB-231 cells, and also led to Fas mediated intrinsic apoptotic pathway by activating caspases -8, -9, -3 and PARP1 cleavage. In nude mice, pRNAi-Stat3 significantly suppressed tumor growth compared with controls. It also suppressed Stat3 expression, and downregulated BcL-xL and upregulated Fas, Fas-L and cleaved caspase-3 expression within the tumor, which significantly induced apoptosis and led to tumor suppression. Thus, targeting Stat3 signaling using siRNA may serve as a novel therapeutic strategy for the treatment of breast cancers expressing constitutively activated Stat3.

Matrix metalloproteinase-9 inhibition down-regulates radiation-induced nuclear factor-kappa B activity leading to apoptosis in breast tumors.

PURPOSE: Novel strategies are needed to prevent the high mortality rates of several types of cancer. These high rates stem from tumor resistance to radiation therapy, which is thought to result from the induction of matrix metalloproteinases (MMP) and plasminogen activators. In the present study, we show that the modulation of MMP-9 expression, using adenoviral-mediated transfer of the antisense MMP-9 gene (MMP-9 adenoviral construct, Ad-MMP-9), affects breast cancer sensitivity to radiation. EXPERIMENTAL DESIGN: In the present study, we used antisense Ad-MMP-9 to down-regulate the expression of MMP-9 in MDA MB 231 breast cancer cell lines in vitro before irradiation and subsequently incubated cells in hypoxic condition. In vivo studies were done with orthotopic breast tumors, and radiosensitivity was evaluated both in vitro and in vivo. RESULTS: Ad-MMP-9 infection resulted in down-regulation of radiation-induced levels of hypoxia-inducible factor 1 alpha and MMP-9 under hypoxic conditions in MDA MB 231 breast cancer cells. In addition, Ad-MMP-9, in combination with radiation, decreased levels of the transcription factors nuclear factor-kappaB and activator protein 1, both of which contribute to the radioresistance of breast tumors. Finally, the triggering of the Fas-Fas ligand apoptotic cascade, which resulted in the cleavage of PARP-1 and caspase-10, caspase-3, and caspase-7, signifies the efficiency of combined treatment of Ad-MMP-9 and radiation. Treatment with Ad-MMP-9 plus radiation completely regressed tumor growth in orthotopic breast cancer model. CONCLUSIONS: In summary, integrating gene therapy (adenovirus-mediated inhibition of MMP-9) with radiotherapy could have a synergistic effect, thereby improving the survival of patients with breast cancer.

Cks1 regulates cdk1 expression: a novel role during mitotic entry in breast cancer cells.

Cks1, a small protein whose expression is strongly associated with aggressive breast tumors, is a component of cyclin-cdk complexes, as well as the SCF(Skp2) ubiquitin ligase. In these studies, we explored its roles in estrogen receptor-positive breast tumor cells. When exposed to the antiestrogen ICI 182780, these cells accumulate in G(1) by reducing the expression of Cks1, and increasing the levels of p130/Rb2, a cdk2 inhibitor and SCF(Skp2) target. Heregulin beta1 or estradiol abrogate antiestrogen effects by increasing Cks1 expression, down-regulating p130/Rb2 and inducing S phase entry. Depletion of Cks1 in these cells by RNA interference concomitantly decreased Skp2 and up-regulated p130/Rb2 and another SCF(Skp2) target, p27(Kip1). Remarkably, however, Cks1-depleted cells not only exhibit slowed G(1) progression, but also accumulate in G(2)-M due to blocked mitotic entry. Notably, we show that cdk1 expression, which is crucial for M phase entry, is drastically diminished by Cks1 depletion, and that restoration of cdk1 reduces G(2)-M accumulation in Cks1-depleted cells. cdk1 reduction in Cks1-depleted cells is a consequence of a marked decrease in its mRNA and not due to alteration in its proteolytic turnover. Both heregulin beta1 and estradiol could neither restore cdk1 nor sustain cycling in Cks1-depleted cells, although classical estrogen receptor function remained unaltered. Cks1 depletion also decreased Skp2 in human mammary epithelial cells without altering cell cycle progression. Thus, the indispensability of Cks1 to the breast cancer cell cycle, versus its redundancy in normal cells, suggests that Cks1 abrogation could be an effective interventional strategy in breast cancer.

Long-term results of RTOG trial 8911 (USA Intergroup 113): a random assignment trial comparison of chemotherapy followed by surgery compared with surgery alone for esophageal cancer.

PURPOSE: We update Radiation Therapy Oncology Group trial 8911 (USA Intergroup 113), a comparison of chemotherapy plus surgery versus surgery alone for patients with localized esophageal cancer. The relationship between resection type and between tumor response and outcome were also analyzed. PATIENTS AND METHODS: The chemotherapy group received preoperative cisplatin plus fluorouracil. Outcome based on the type of resection (R0, R1, R2, or no resection) was evaluated. The main end point was overall survival. Disease-free survival, relapse pattern, the influence of postoperative treatment, and the relationship between response to preoperative chemotherapy and outcome were also evaluated. RESULTS: Two hundred sixteen patients received preoperative chemotherapy, 227 underwent immediate surgery. Fifty-nine percent of surgery only and 63% of chemotherapy plus surgery patients underwent R0 resections (P = .5137). Patients undergoing less than an R0 resection had an ominous prognosis; 32% of patients with R0 resections were alive and free of disease at 5 years, only 5% of patients undergoing an R1 resection survived for longer than 5 years. The median survival rates for patients with R1, R2, or no resections were not significantly different. While, as initially reported, there was no difference in overall survival for patients receiving perioperative chemotherapy compared with the surgery only group, patients with objective tumor regression after preoperative chemotherapy had improved survival. CONCLUSION: For patients with localized esophageal cancer, whether or not preoperative chemotherapy is administered, only an R0 resection results in substantial long-term survival. Even microscopically positive margins are an ominous prognostic factor. After a R1 resection, postoperative chemoradiotherapy therapy offers the possibility of long-term disease-free survival to a small percentage of patients.

RNAi-mediated downregulation of urokinase plasminogen activator receptor and matrix metalloprotease-9 in human breast cancer cells results in decreased tumor invasion, angiogenesis and growth.

The serine protease urokinase-type plasminogen activator (uPA) plays a significant role in tumor cell invasion and metastasis when bound to its specific receptor, uPAR (also known as CD87). In addition to the uPA-uPAR system, matrix metalloproteinases (MMPs) are involved in tumor cell invasion and metastasis. In this study, we achieved specific inhibition of uPAR and MMP-9 using RNAi technology. We introduced small interfering RNA to downregulate the expression of uPAR and MMP-9 (pUM) in breast cancer cell lines (MDA MB 231 and ZR 75 1). In vitro angiogenesis studies indicated a decrease in the angiogenic potential of the treated cells; in particular, a remarkable decrease was observed in the cells treated with bicistronic construct (pUM) in comparision to the controls. Additionally, bicistronic construct inhibited the formation of capillary-like structures in in vivo models of angiogenesis. Similarly, the invasive potential and migration decreased dramatically when treated with the bicistronic construct as shown by matrigel invasion and migration assays. These results suggest a synergistic effect from the simultaneous downregulation of uPAR and MMP-9. We also assessed the levels of phosphorylated forms of MAPK, ERK and AKT signaling pathway molecules and found reduction in the levels of these molecules in cells treated with the bicistronic construct as compared to the control cells. Furthermore, targeting both uPAR and MMP-9 totally regressed orthotopic breast tumors in nude mice. In conclusion, our results provide evidence that the simultaneous downregulation of uPAR and MMP-9 using RNAi technology may provide an effective tool for breast cancer therapy.

Demethylation-linked activation of urokinase plasminogen activator is involved in progression of prostate cancer.

Increased expression of urokinase plasminogen activator (uPA) has been reported in various malignancies including prostate cancer. However, the mechanism by which uPA is abnormally expressed in prostate cancer remains elusive. Here, we show that uPA is aberrantly expressed in a high percentage of human prostate cancer tissues but rarely expressed either in tumor-matched nonneoplastic adjacent tissues or benign prostatic hyperplasia samples. This aberrant expression is associated with cancer-linked demethylation of the uPA promoter. Furthermore, treatment with demethylation inhibitor S-adenosylmethionine or stable expression of uPA short hairpin RNA significantly inhibits uPA expression and tumor cell invasion in vitro and tumor growth and incidence of lung metastasis in vivo. Collectively, these findings strongly suggest that DNA demethylation is a common mechanism underlying the abnormal expression of uPA and is a critical contributing factor to the malignant progression of human prostate tumors.

MEK ablation in MCF-7 cells blocks DNA synthesis induced by serum, but not by estradiol or growth factors.

The role of mitogen-activated protein/extracellular signal-regulated kinase kinase (MEK) signaling in estrogen receptor positive (ER(+)) MCF-7 breast carcinoma cells is not well understood. We depleted MEK by cotransfection of MEK1 and MEK2 siRNA duplexes in a MCF-7 derived line (MCF-7/ lacZ, ML-20) and determined its effect on serum, 17beta-estradiol (E(2)), and growth factor induced DNA synthesis. MEK knockdown did not decrease fetal bovine serum-induced DNA synthesis in ML-20 cells although it did inhibit DNA synthesis induced by estrogen-stripped calf serum (CCS) suggesting that MEK activation plays an important role in growth signaling induced by serum components other than estrogen. Consistent with this notion, MEK knockdown only modestly decreased DNA synthesis induced by E(2)-supplemented CCS medium in ML-20 cells. Similarly, MEK knockdown only caused moderate decreases in DNA synthesis induced by fibroblast growth factor-1 (FGF-1) or heregulin-beta1 (HRGbeta1) in this media. Also, there were only minimal effects of MEK knockdown in cells treated with growth factor-supplemented serum-free medium. Although MEK depletion inhibited ERK1/2 phosphorylation induced by CCS in these cells, that induced by growth factor supplemented CCS media was relatively unaffected. Similarly, ERK1/2 phosphorylation induced by growth factor-supplemented serum-free media was also relatively unaffected by MEK depletion. These results suggest that pathways regulating DNA synthesis induced by serum in MCF-7 cells are significantly more dependent on constitutive MEK levels than that induced by E(2) or growth factors.

Phase III trial of fluorouracil-based chemotherapy regimens plus radiotherapy in postoperative adjuvant rectal cancer: GI INT 0144.

PURPOSE: Adjuvant chemoradiotherapy after or before resection of high-risk rectal cancer improves overall survival (OS) and pelvic control. We studied three postoperative fluorouracil (FU) radiochemotherapy regimens. PATIENTS AND METHODS: After resection of T3-4, N0, M0 or T1-4, N1, 2M0 rectal adenocarcinoma, 1,917 patients were randomly assigned to arm 1, with bolus FU in two 5-day cycles every 28 days before and after radiotherapy (XRT) plus FU via protracted venous infusion (PVI) 225 mg/m2/d during XRT; arm 2 (PVI-only arm), with PVI 42 days before and 56 days after XRT + PVI; or arm 3 (bolus-only arm), with bolus FU + leucovorin (LV) in two 5-day cycles before and after XRT, plus bolus FU + LV (levamisole was administered each cycle before and after XRT). Patients were stratified by operation type, T and N stage, and time from surgery. RESULTS: Median follow-up was 5.7 years. Lethal toxicity was less than 1%, with grade 3 to 4 hematologic toxicity in 49% to 55% of the bolus arms versus 4% in the PVI arm. No disease-free survival (DFS) or OS difference was detected (3-year DFS, 67% to 69% and 3-year OS, 81% to 83% in all arms). Locoregional failure (LRF) at first relapse was 8% in arm 1, 4.6% in arm 2, and 7% in arm 3. LRF in T1-2, N1-2, and T3, N0-2 primaries who received low anterior resection (those most suitable for primary resection) was 5% in arm 1, 3% in arm 2, and 5% in arm 3. CONCLUSION: All arms provide similar relapse-free survival and OS, with different toxicity profiles and central catheter requirements. LRF with postoperative therapy is low, justifying initial resection for T1-2, N0-2 and T3, and N0-2 anterior resection candidates.