Local excision of rectal cancer followed by radical surgery because of poor prognostic features does not compromise the long term oncologic outcome.

AIM: The outcome of patients undergoing full-thickness local excision (LE) of rectal cancers may be compromised if poor prognostic features are found in the LE specimen. Our aim was to evaluate the long-term results of radical surgery performed after LE because poor prognostic factors are identified. METHOD: Patients with biopsy-proven rectal cancer who had undergone full-thickness LE followed by radical surgery because of a positive margin, T stage ≥3, lymphovascular invasion, poor differentiation or mucinous histology were identified from a prospective database. Their records were retrospectively reviewed and follow up was updated. RESULTS: Between 1995 and 2003, 17 patients underwent LE followed by radical surgery because of poor prognostic features. Combined chemotherapy and radiotherapy was given to 11 (65%) patients before radical surgery. Patients underwent radical surgery after a median of 14 (range: 0-40) weeks from LE. Nine underwent a low anterior resection and eight an abdominoperineal resection. At the time of radical surgery, residual disease was found in six (35%) patients (in lymph nodes in three; intramural in two; and both lymph nodes and intramural in one). Four of the patients with residual disease had undergone neoadjuvant therapy before radical surgery. The mean follow up was 110 (95% CI: 92-129) months. Recurrence-free survival at 10 years was 88%. There was no case of local recurrence, and two patients died of metastatic disease. CONCLUSION: In this series patients who underwent early radical surgery because of poor prognostic features found at LE had good overall and cancer-specific long-term survival. Even after neoadjuvant therapy, more than a third of patients had residual disease at the time of radical surgery. We therefore recommend radical surgery with neoadjuvant therapy when poor prognostic features are found at LE.

Paclitaxel sensitivity of breast cancer cells with constitutively active NF-kappaB is enhanced by IkappaBalpha super-repressor and parthenolide.

The transcription factor nuclear factor-kappaB (NF-kappaB) regulates genes important for tumor invasion, metastasis and chemoresistance. Normally, NF-kappaB remains sequestered in an inactive state by cytoplasmic inhibitor-of-kappaB (IkappaB) proteins. NF-kappaB translocates to nucleus and activates gene expression upon exposure of cells to growth factors and cytokines. We and others have shown previously that NF-kappaB is constitutively active in a subset of breast cancers. In this study, we show that constitutive activation of NF-kappaB leads to overexpression of the anti-apoptotic genes c-inhibitor of apoptosis 2 (c-IAP2) and manganese superoxide dismutase (Mn-SOD) in breast cancer cells. Furthermore, expression of the anti-apoptotic tumor necrosis factor receptor associated factor 1 (TRAF1) and defender-against cell death (DAD-1) is regulated by NF-kappaB in certain breast cancer cells. We also demonstrate that NF-kappaB-inducible genes protect cancer cells against paclitaxel as MDA-MB-231 breast cancer cells modified to overexpress IkappaBalpha required lower concentrations of paclitaxel to arrest at the G2/M phase of the cell cycle and undergo apoptosis when compared to parental cells. The effect of NF-kappaB on paclitaxel-sensitivity appears to be specific to cancer cells because normal fibroblasts derived from embryos lacking p65 subunit of NF-kappaB and wild type littermate embryos were insensitive to paclitaxel-induced G2/M cell cycle arrest. Parthenolide, an active ingredient of herbal remedies such as feverfew (tanacetum parthenium), mimicked the effects of IkappaBalpha by inhibiting NF-kappaB DNA binding activity and Mn-SOD expression, and increasing paclitaxel-induced apoptosis of breast cancer cells. These results suggest that active ingredients of herbs with anti-inflammatory properties may be useful in increasing the sensitivity of cancers with constitutively active NF-kappaB to chemotherapeutic drugs. Oncogene (2000) 19, 4159 - 4169

Y2 receptors decrease human pancreatic cancer growth and intracellular cyclic adenosine monophosphate levels.

BACKGROUND: Peptide YY (PYY), a 36 amino acid enteric hormone, is known to decrease pancreatic exocrine and endocrine function. Previous studies with BIM-43004-1, a modified PYY(22-36) Y2 receptor agonist, have revealed diminished mitochondrial activity in pretreated pancreatic cancer cells in vitro. We investigated the effects of both PYY and BIM-43004-1 on pancreatic cancer growth in vivo. METHODS: The 100,000 to 150,000 human pancreatic cancer cells, Mia PaCa-2, were orthotopically transplanted into 48 male athymic mice. After 1 week animals were treated with either PYY or BIM-43004-1 at 200 pmol/kg/hr via miniosmotic pumps for 2, 3, or 4 weeks. Paired controls received saline solution. At death tumor size and mass were measured. Receptor binding studies and intracellular cyclic adenosine monophosphate (cAMP) levels were measured in vitro. RESULTS: All mice had significant human cancer growth within the pancreas by histologic sections at 2, 3, and 4 weeks. Tumor mass was decreased by 60.5% in BIM-43004-1 treated mice and 27.1% in PYY treated mice. Receptor binding studies revealed binding of [125I]-BIM-43004-1 and displacement of ligand on competitive addition of nonradioactive BIM-43004-1. K dissociation constant of 4.5 nmol and 27,000 receptors per cell were quantitated by receptor binding studies. In BIM-43004-1 treated pancreatic cells a 52.5% decrease in intracellular cAMP levels was noted, whereas a 15.3% decrease was seen in PYY treated cells. CONCLUSIONS: BIM-43004-1, a novel Y2 synthetic agonist, specifically binds to human pancreatic cancer cells, decreases intracellular cAMP levels, and suppresses tumor growth in vivo. Adjuvant hormonal treatment with this Y2 receptor analog may be beneficial in the treatment of patients with pancreatic adenocarcinoma.

Peptide YY: a potential proabsorptive hormone for the treatment of malabsorptive disorders.

Peptide YY (PYY) is a 36 amino acid peptide that is released from the endocrine cells of the distal ileum, colon, and rectum following a meal. PYY is strongly proabsorptive in the small intestine. We studied the effects of intravenous PYY on colonic water and electrolyte transport in awake dogs. Dogs had 20 cm neurovascularly intact colon Thiry-Vella fistulas (TVS) surgically constructed. Colonic transport was studied in three experimental groups. Group 1 animals received a standard mixed meal. Group 2 animals were unfed and received intravenous PYY and 100 pmol/kg/hr for two hours. This dose of PYY has previously been shown to simulate the plasma levels of PYY normally seen after a meal. Group 3 received intravenous PYY at the same dose in addition to a mixed meal. Our study shows an increase in colonic water, Na+, and Cl- absorption after a meal (P < 0.05). Infusion of PYY at a 100 pmol/kg/hr was significantly proabsorptive beginning at 60 minutes (P < 0.01). Infusion of PYY in addition to a meal further increased absorption (P < 0.05). PYY is a potent proabsorptive agent in the colon of the conscious dog. PYY, or its analogs, may be useful clinical agents in intestinal malabsorptive disorders or after bowel resection.

NF-kappaB activation and interleukin 6 production in fibroblasts by estrogen receptor-negative breast cancer cell-derived interleukin 1alpha.

Several angiogenic factors and extracellular matrix-degrading enzymes that promote invasion and metastasis of cancer are produced by stromal fibroblasts that surround cancer cells. The expression of genes that code for some of these proteins is regulated by the transcription factor NF-kappaB. In this report, we demonstrate that conditioned medium (CM) from estrogen receptor (ER)-negative but not ER-positive breast cancer cells induces NF-kappaB in fibroblasts. In contrast, CM from both ER-positive and ER-negative breast cancer cells induces NF-kappaB in macrophages and endothelial cells. NF-kappaB activation in fibroblasts was accompanied by induction of interleukin 6 (IL-6) and urokinase plasminogen activator (uPA), both of which promote angiogenesis and metastasis. A survey of cytokines known for their ability to induce NF-kappaB identified IL-1alpha as the factor responsible for NF-kappaB activation in fibroblasts. Analysis of primary breast carcinomas revealed the presence of IL-1alpha transcripts in majority of lymph node-positive breast cancers. These results along with the known role of IL-1alpha and IL-6 in osteoclast formation provide insight into the mechanism of metastasis and hypercalcemia in advanced breast cancers.

Intraluminal peptide YY induces colonic absorption in vivo.

INTRODUCTION: Peptide YY (PYY) is a 36 amino acid hormone released into the circulation and lumen of the intestine after a meal. Previous studies have shown that exogenous administration of intravenous PYY stimulates water and electrolyte absorption in both the small and large intestines. The purpose of this study was to examine the effects of intraluminal administration of PYY on colonic absorption of electrolytes and water. METHODS: Six conditioned 25-kg dogs had 20 cm of colonic Thiry-Vella fistulae surgically constructed under general anesthesia. After a two-week recovery period, the animals received intraluminal PYY at 600 pmol/kg/hour after a 90-minute steady-state basal period. The Thiry-Vella fistulae were perfused with an isotonic buffer solution containing [14C]polyethylene glycol as a volume marker. Ion and water transport were measured every 15 minutes. RESULTS: On intraluminal infusion of PYY, increased absorption of water, sodium, and chloride was observed in the colon. A twofold increase in absorption rates occurred compared with basal rates lasting more than one hour after cessation of intraluminal PYY (N = 6; P < 0.05 vs. basal by analysis of variance). CONCLUSION: PYY-secreting cells of the colon may contribute to the regulation of absorption after a meal. Exogenous administration of intraluminal PYY may also be a therapeutic treatment modality for malabsorption.

Negative regulation of transactivation function but not DNA binding of NF-kappaB and AP-1 by IkappaBbeta1 in breast cancer cells.

The transcription factor NF-kappaB regulates the expression of genes involved in cancer cell invasion, metastasis, angiogenesis, and resistance to chemotherapy. In normal cells NF-kappaB is maintained in the cytoplasm by protein-protein interaction with inhibitor IkappaBs. In contrast, in cancer cells a substantial amount of NF-kappaB is in the nucleus and constitutively activates target genes. To understand the mechanisms of constitutive NF-kappaB activation, we have analyzed the function of IkappaBalpha and IkappaBbeta in breast cancer cells. In most cases, constitutive NF-kappaB DNA binding correlated with reduced levels of either IkappaBalpha or IkappaBbeta isoforms. Overexpression of IkappaBalpha but not IkappaBbeta1 resulted in reduced constitutive DNA binding of NF-kappaB in MDA-MB-231 cells. Unexpectedly, IkappaBbeta1 overexpression moderately increased 12-O-tetradecanoylphorbol-13-acetate- and interleukin-1-inducible NF-kappaB DNA binding. 12-O-Tetradecanoylphorbol-13-acetate- and interleukin-1-induced transactivation by NF-kappaB, however, was lower in IkappaBbeta1-overexpressing cells. Mutants of IkappaBbeta1 lacking the C-terminal casein kinase II phosphorylation sites, which form a stable complex with DNA bound NF-kappaB without inhibiting its transactivation in other cell types, repressed the transactivation by NF-kappaB in MDA-MB-231 cells. Consistent with the results of transient transfections, the expression of urokinase plasminogen activator, an NF-kappaB target gene, was reduced in IkappaBbeta1-overexpressing cells. These results suggest that depending on the cell type, IkappaBbeta1 represses the expression of NF-kappaB-regulated genes by inhibiting either DNA binding or transactivation function of NF-kappaB.

EGF and TGF stimulate proabsorption of glucose and electrolytes by Na+/glucose cotransporter in awake canine model.

Growth factor-stimulated intestinal absorption has recently been described, but the cellular transport mechanisms mediating this response are unknown. The purposes of this study were to examine the effect that intraluminal and systemic EGF and TGF have in intestinal absorption, elucidate a possible mechanism through which they exert their activity, and compare this response to that of a mixed meal only. Jejunal and ileal Thiry-Vella intestinal segments were constructed in six dogs. Absorption was measured by infusing the loops with a physiological electrolyte solution containing either 10 mmol or 50 mmol glucose and [14C]PEG as the impermeant marker. In vivo studies show that the addition of either EGF or TGF resulted in increased absorption of Na+, Cl-, H2O, and glucose in the intestine. This response was significantly greater than that seen when giving a mixed meal alone. Luminal phloridzin, an inhibitor of the SGLT-1 transporter, inhibited intestinal absorption observed in response to EGF and TGF. In conclusion, these results suggest that growth factors are capable of up-regulating intestinal absorption of electrolytes and nutrients and, these effects are mediated, at least in part, by SGLT-1 pathways.

Tumour necrosis factor and PI3-kinase control oestrogen receptor alpha protein level and its transrepression function.

Oestrogen receptor alpha (ERalpha) is an oestrogen-activated transcription factor, which regulates proliferation and differentiation of mammary epithelial cells by activating or repressing gene expression. ERalpha is a critical prognostic indicator and a therapeutic target for breast cancer. Patients with tumours that express higher level of ERalpha have better prognosis than patients with tumours that are ERalpha negative or express lower level of ERalpha. Better prognosis in ERalpha-positive patients is believed to be due to repression of proinvasive gene expression by ERalpha. Oestrogen receptor alpha represses gene expression by transrepressing the activity of the transcription factors such as nuclear factor-kappaB or by inducing the expression of transcriptional suppressors such as MTA3. In this report, we show that ERalpha transrepresses the expression of the proinvasive gene interleukin 6 (IL-6) in ERalpha-negative MDA-MB-231 breast cancer cells stably overexpressing ERalpha. Using these cells as well as ERalpha-positive MCF-7 and ZR-75-1 cells, we show that tumour necrosis factor alpha (TNFalpha) and the phosphatidylinositol-3-kinase (PI3-kinase) modulate transrepression function of ERalpha by reducing its stability. From these results, we propose that TNFalpha expression or PI3-kinase activation lead to reduced levels of ERalpha protein in cancer cells and corresponding loss of transrepression function and acquisition of an invasive phenotype.

A novel synthetic analog of peptide YY, BIM-43004, given intraluminally, is proabsorptive.

Peptide YY (PYY), a proabsorptive hormone, is released into the circulation and lumen of the small intestine after a meal. We have recently found that intraluminal PYY is proabsorptive in the ileum. The purpose of this study was to examine the effects of intraluminal administration of a new substituted PYY (22-36) analog on intestinal absorption of electrolytes and water. Twelve conditioned 20-kg dogs had 25-cm jejunal, 25-cm ileal, or 20-cm colonic Thiry-Vella fistulas (TVF) surgically constructed under general anesthesia (jejunal and ileal TVF, N = 6, and colonic TVF, N = 6). After a 2-week recovery period, the animals received the intraluminal PYY analog, BIM-43004, in the ileum (200 pmole/kg) or colon (300 pmole/kg) for 60 min after a 90-min steady-state basal period was confirmed. The TVF were perfused with an isotonic buffer solution containing [14C]polyethylene glycol as a volume marker. Ion and water transport were measured every 15 min. Net water absorptions were significant in the ileum and colon but not in the jejunum upon intraluminal administration of the PYY analog, BIM-43004. Colonic water absorptions were increased more than twofold above basal absorption rates and ileal absorptions were increased more than 1.5-fold upon addition of intraluminal BIM-43004. Sodium and chloride ion absorption in the colon and ileum paralleled water fluxes. We are describing for the first time a synthetic peptide analog of PYY that produces significant water and electrolyte absorption in the ileum and colon when administered luminally. This synthetic analog may have therapeutic potential in patients with malabsorptive disorders.

Cholecystokinin mediation of colonic absorption via peptide YY: foregut-hindgut axis.

Peptide YY (PYY), a 36-amino-acid polypeptide, is found in abundance in the colon, a region where its physiologic roles are unknown. Previous studies have revealed a substantial increase in plasma PYY after cholecystokinin (CCK) administration. PYY is released from the hindgut in response to a meal and inhibits CCK release. In this study we evaluated the effects of CCK and PYY on intestinal absorption of water and electrolytes. Colonic, ileal, or jejunal Thiry-Vella fistulas (TVFs) were created in 12 dogs, and intestinal continuity was reestablished. The TVFs were perfused with an isotonic buffer solution containing [14C] PEG as a volume marker. Electrolyte and water transport were measured every 15 minutes, and plasma PYY and CCK levels were measured by radioimmunoassay. Group 1 dogs received an intravenous bolus of MK329, a specific CCK receptor antagonist, at 20 nmol/kg after a standard mixed meal; group 2 colonic TVF dogs received a meal and an intravenous bolus of PYY polyclonal antibody at 1 mg/kg. Postprandially, all three regions of the bowel became significantly proabsorptive for water, sodium, and chloride. In the colon postprandial absorption was abolished by MK329 starting 60 minutes after a meal, whereas specific CCK receptor blockade blunted ileal absorption. CCK receptor blockade did not affect postprandial absorption in the jejunum. Postprandial PYY levels did not rise in MK329-treated animals. PYY antibody reduced colonic absorption during the postprandial phase. Reduction of meal-induced colonic absorption and PYY release by MK329 in awake dogs suggests an important foregut-hindgut hormonal feedback loop. Foregut-derived CCK stimulates hindgut PYY release, which in turn stimulates colonic absorption while inhibiting further CCK release.