Lymph node ratio is an independent prognostic factor in patients with rectal cancer treated with preoperative chemoradiotherapy and curative resection

PURPOSE

To evaluate the prognostic effect of lymph node ratio (LNR) in patients with locally advanced rectal cancer who were treated with curative resection after preoperative chemoradiotherapy (CRT).

METHODS

Between October 2001 and December 2007, 519 patients who had undergone curative resection of primary rectal cancer after preoperative CRT were enrolled. Of these, 154 patients were positive for lymph node (LN) metastasis and were divided into three groups according to the LNR (≤ 0.15 [n=80], 0.16-0.3 [n=44], >0.3 [n=30]) to evaluate the prognostic effect on overall survival (OS) and disease-free survival (DFS).

RESULTS

LNR (≤ 0.15, 0.16-0.3, and >0.3) was significantly associated with 5-year OS (90.3%, 75.1%, and 45.1%; p<0.001) and DFS (66.7%, 55.8%, and 21.9%; p<0.001) rates. In a multivariate analysis, LNR (≤ 0.15, 0.16-0.3, and >0.3) was a significant independent prognostic factor for OS (hazard ratios [HRs], 1, 3.609, and 8.197; p<0.001) and DFS (HRs, 1, 1.699, and 3.960; p<0.001). LNR had a prognostic impact on OS and DFS in patients with <12 harvested LNs, as well as in those with ≥ 12 harvested LNs (p<0.05).

CONCLUSION

LNR was a significant independent prognostic predictor for OS and DFS in patients with locally advanced rectal cancer who were treated with curative resection after preoperative CRT.

Two cation transporters Ena1 and Nha1 cooperatively modulate ion homeostasis, antifungal drug resistance, and virulence of Cryptococcus neoformans via the HOG pathway

Maintenance of cation homeostasis is essential for survival of all living organisms in their biological niches. It is also important for the survival of human pathogenic fungi in the host, where cation concentrations and pH will vary depending on different anatomical sites. However, the exact role of diverse cation transporters and ion channels in virulence of fungal pathogens remains elusive. In this study we functionally characterized ENA1 and NHA1, encoding a putative Na(+)/ATPase and Na(+)/H(+) antiporter, respectively, in Cryptococcus neoformans, a basidiomycete fungal pathogen which causes fatal meningoencephalitis. Expression of NHA1 and ENA1 is induced in response to salt and osmotic shock mainly in a Hog1-dependent manner. Phenotypic analysis of the ena1Δ, nha1Δ, and ena1Δnha1Δ mutants revealed that Ena1 controls cellular levels of toxic cations, such as Na(+) and Li(+) whereas both Ena1 and Nha1 are important for controlling less toxic K(+) ions. Under alkaline conditions, Ena1 was highly induced and required for growth in the presence of low levels of Na(+) or K(+) salt and Nha1 played a role in survival under K(+) stress. In contrast, Nha1, but not Ena1, was essential for survival at acidic conditions (pH 4.5) under high K(+) stress. In addition, Ena1 and Nha1 were required for maintenance of plasma membrane potential and stability, which appeared to modulate antifungal drug susceptibility. Perturbation of ENA1 and NHA1 enhanced capsule production and melanin synthesis. However, Nha1 was dispensable for virulence of C. neoformans although Ena1 was essential. In conclusion, Ena1 and Nha1 play redundant and discrete roles in cation homeostasis, pH regulation, membrane potential, and virulence in C. neoformans, suggesting that these transporters could be novel antifungal drug targets for treatment of cryptococcosis.

Carotid atherosclerosis in patients with untreated chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is associated with systemic inflammation.

OBJECTIVE

To evaluate carotid artery intima-media thickness (IMT), high sensitivity C-reactive protein (hsCRP) and their correlation in newly diagnosed untreated patients with COPD.

DESIGN

Post-bronchodilator spirometry, carotid artery IMT and blood tests were measured in patients with COPD (COPD group). Age, sex, body mass index, smoking status and smoking amount were compared with matched healthy subjects (non-COPD group). Participants taking medications and/or with a history of hypertension, diabetes mellitus, dyslipidaemia, COPD or cardiovascular disease were excluded.

RESULTS

A total of 126 patients (COPD group 42, non-COPD group 84) were enrolled. The IMT and hsCRP of the COPD group were significantly higher than in the non-COPD group (P < 0.05). The decrease in the forced expiratory volume in 1 second/forced vital capacity (FEV(1)/FVC) ratio and FEV(1) was significantly correlated with an increase in the hsCRP and IMT (P < 0.05); there was no correlation between the IMT and hsCRP (P = 0.152).

CONCLUSION

In newly diagnosed untreated patients with COPD, the carotid artery IMT and hsCRP were significantly higher than in healthy subjects. These findings suggest that systemic inflammation may play a potential role in preclinical atherosclerosis in COPD.

P5-13-11: PTEN and Tau-Protein Expression: Predictive Value of Poor Response to Trastuzumab Plus Paclitaxel in Patients with HER2−Positive Breast Cancer

Backgrounds: Trastuzumab-based chemotherapy has been an active treatment in patients (pts) with HER2−positive breast cancer; however, primary and secondary resistance has occurred in pts treated with trastuzumab (H) alone or in combination with chemotherapy. Material and Methods: Biomarkers were searched using tissue microarrays (TMA) in the HER2−positive breast cancer pts treated with H and paclitaxel (P) combination chemotherapy between October 2004 and August 2010. Tumor blocks of 101 pts were analyzed for VEGF, IGF-1R, p-Akt, beta-III tubulin, CD44, Tau-protein, p27 and PTEN by immunohistochemical (IHC) analysis. Eight biomarkers were assessed to investigate the correlation with the clinical outcomes, including response rate (RR), progression free survival (PFS), and overall survival (OS).

Results: With a median follow-up duration of 21.7 months (range, 9.1−55.2 months), 101 pts received H+P chemotherapy in neoadjuvant setting (n=36, 35.6%) and recurrent or metastatic setting (n=65, 64.4%). Median age was 48 (range, 19–83 years), and the majority of pts (n=95, 94.1%) had good performance status. Premenopausal pts and hormone receptor-negative pts were 48 (47.5%) and 52 (51.5%), respectively. The median cycle of H+P chemotherapy was six (range, H 1–43; P 1–21). Overall RR was 68.3% (n=69) including complete response with 7 pts, and PFS and OS were significantly longer in pts responsive to H+P chemotherapy compared with non-responsive patients (PFS, p=0.001; OS, p=0.015). Although VEGF, IGF-1R, p-Akt, beta-III tubulin, CD44, p27 and PTEN status by IHC were not significantly associated with response to H+P chemotherapy, Tau-protein showed a trend of association without statistical significance (RR, 46.2% vs. 71.6%, p=0.066). Among 13 pts with high Tau protein expression, 9 pts with both high Tau-protein and low PTEN level showed statistically significant lower RR compared with other 92 pts (22.2% vs. 72.8%; p=0.002). None of the biomarkers was related to PFS and OS in pts with recurrent or metastatic disease, and to pathologic complete response in pts after H+P chemotherapy as neoadjuvant therapy.

Conclusion: Our data showed that both low PTEN level and high Tauprotein expression were significantly associated with poor response to H+P chemotherapy in patients with HER2−positive breast cancer.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-13-11.

High-flexion total knee arthroplasty improves flexion of stiff knees

PURPOSE

High-flexion knee prosthesis designs are generally thought to be of benefit only in patients with a satisfactory preoperative flexion angle. The aim of the study was to evaluate whether high-flexion designs were indeed worthless in osteoarthritis patients with severe preoperative flexion limitation.

METHODS

The postoperative maximum flexion was compared in osteoarthritis patients with a preoperative maximum flexion of 100° or less, using LPS and LPS-flex implants (NexGen®; Zimmer, Warsaw, IN) in total knee arthroplasties. Data on 39 knees in the LPS group and 41 in the LPS-flex group, with a minimum of 2 years of follow-up, were reviewed retrospectively, focused on the postoperative maximum flexion.

RESULTS

Two years after operation, the LPS-flex group had a mean postoperative maximum flexion of 131±10° (range, 105-140°), which was significantly higher than the 121±12° (range, 95-140°) in the LPS group (P<0.001). In the LPS-flex group, about half of the knees (n=18, 44%) could achieve a maximum flexion of 140° postoperatively, but in the LPS group only five knees (13%) achieved a maximum flexion of 140°.

CONCLUSION

Despite a different period of the operation between groups, this study suggested that osteoarthritis patients with severe preoperative flexion limitation could achieve more postoperative gain in flexion when a high-flexion prosthesis was used, compared to the flexion obtained using a standard prosthesis.

Acetabularia rhodopsin I is a light-stimulated proton pump

We cloned an intronless, nuclear-encoded opsin gene from an EST library of Acetabularia acetabulum. Acetabularia rhodopsin I (ARI) encodes a protein of 246 amino acids with molecular weight of 27 kDa. ARI was reconstituted in the Xenopus oocyte expression system to characterize its electrophysiological properties utilizing the two-electrode voltage-clamping technique. Oocytes where ARI cRNA was injected displayed outward directed currents in response to light. The maximum action spectrum of ARI was detected at 520 nm green light. Light-stimulated ARI current amplitude was altered by the protons, but not by the other ions in recording solutions, suggesting that the algal rhodopsin is a light-stimulated proton pump. Typical proton-mediated outward current elicited by 520 nm light was characterized with two phases of non-inactivating outward current following initial transient current. Taken together, we here reported cloning of a novel Acetabularia opsin gene which was characterized to be a proton-pump stimulated by light.

ATP regeneration system using E. coli ATP synthase and Gloeobacter rhodopsin and its stability

Great efforts in using non-photosynthetic bacteria as light-utilizing bacteria for producing biomaterials have been developed recently as increasing interest in renewable resources such as light energy. With respect to producing bio-materials industrially such as food ingredients and amino acids, huge amount of adenosine-5'-triphosphate (ATP) is required. In this work, we developed a bio-ATP-synthesis system using ATP synthase of Escherichia coil as a biocatalyst and a microbial rhodopsin which is from primitive cyanobacteria, Gloeobacter violaceus. Gloeobacter rhodopsin (GR) is a light-driven proton pump. Besides electro-chemical gradient produced by cellular respiration system, GR produces a proton gradient using light illumination which is used in additional driving force of synthesizing ATP by ATP synthase. Inverted membrane vesicle was prepared so that it could be incorporated with both of GR and ATP synthase and produced ATP in the exterior side of the vesicle in the presence of light. Since inverted membrane vesicle does not contain precursors for ATP, we added ADP and inorganic phosphate (P(i)). Then, we measured the amounts of ATP produced by ATP synthase in the presence of light. As the average value of 6 samples, 4.79 x 10(-2) micromole of ATP produced for 1 microg of GR per minute. Also, we measured again after 7 days and 65 days, respectively, in order to check the stability of the bio-ATP-synthesis system. Amount of ATP produced decayed double-exponentially and an expected value of half-life of the system was 1.5 days and 39.7 days. Our results demonstrate that ATP was regenerated successfully by using GR and ATP synthase. However, the stability of ATP synthase should be increased to use this system industrially in the near future.

An inward proton transport using Anabaena sensory rhodopsin

ATP is synthesized by an enzyme that utilizes proton motive force and thus nature creates various proton pumps. The best understood proton pump is bacteriorhodopsin (BR), an outward-directed light-driven proton pump in Halobacterium salinarum. Many archaeal and eubacterial rhodopsins are now known to show similar proton transport activity. Proton pumps must have a specific mechanism to exclude transport in the reverse direction to maintain a proton gradient, and in the case of BR, a highly hydrophobic cytoplasmic domain may constitute such machinery. Although an inward proton pump has neither been created naturally nor artificially, we recently reported that an inward-directed proton transport can be engineered from a bacterial rhodopsin by a single amino acid replacement Anabaena sensory rhodopsin (ASR) is a photochromic sensor in freshwater cyanobacteria, possessing little proton transport activity. When we replace Asp217 at the cytoplasmic domain (distance ∼ 15 Å from the retinal chromophore) to Glu, ASR is converted into an inward proton transport, driven by absorption of a single photon. FTIR spectra clearly show an increased proton affinity for Glu217, which presumably controls the unusual directionality opposite to normal proton pumps.

Abstract P1-01-08: Lymph Node Ratio as an Alternative to pN Staging in Node Positive Breast Cancer: A report from the Korean Breast Cancer Society

Background: To compare the lymph node ratio(LNR) and pN staging as a prognostic predictor and find out high risk subgroup which can not predict prognosis using pN staging.

Patients and Methods: Using information from two large databases, including Korean nationwide registry, we compared the survival using LNR and pN stage parameters by Cox regression analysis. Moreover survival data were analysed according to age subgroups and intrinsic subtypes. Results: In an analysis of 2264 node positive patients from single institution, adjusted cancer specific mortality risks of low (≥0.20), intermediate (&gt;0.20 and ≥0.65) and high risk (&gt;0.65) LNR groups were 1(reference), 1.9 (95%CI, 1.6 to 2.4), 4.6(95%CI, 3.6 to 5.8). The difference of mortality risk between LNR parameters were wider than that of N1, N2 and N3 in DFS, CSS, OS. In contrast to LNR risk categories, survival curve in pN1 and pN2 overlapped in the patients below 35 years old. Survival curve in pN1 and pN2 also overlapped in patients in her2/neu enriched as well as triple negative subtype. These finding were validated by an analysis of nationwide registry data on 15488 node positive patients. The patients who had N1 and LNR2-3 disease showed poor DFS (HR 1.7 95% CI 1.4 to 2.2) and CSS (HR 1.6, 95% CI 1.1 to 2.2) compared with the patients who had N2 and LNR1 disease. Conclusion: LNR define breast cancer prognosis more adequate than the pN categories especially high risk breast cancer like young age, her2/neu enriched and triple negative intrinsic subtype. It is more reasonable that treatment decision like radiotherapy might be depend on the LNR than pN staging. We argue that LNR should be considered as an alternative to pN staging.

Figures available in online version.

Comparison of mammography, sonography, MRI and clinical examination in patients with locally advanced or inflammatory breast cancer who underwent neoadjuvant chemotherapy

OBJECTIVES

The purpose of this study was to determine the relative accuracies of mammography, sonography, MRI and clinical examination in predicting residual tumour size and pathological response after neoadjuvant chemotherapy for locally advanced or inflammatory breast cancer. Each prediction method was compared with the gold standard of surgical pathology.

METHODS

43 patients (age range, 25-62 years; mean age, 42.7 years) with locally advanced or inflammatory breast cancer who had been treated by neoadjuvant chemotherapy were enrolled prospectively. We compared the predicted residual tumour size and the predicted response on imaging and clinical examination with residual tumour size and response on pathology. Statistical analysis was performed using weighted kappa statistics and intraclass correlation coefficients (ICC).

RESULTS

The ICC values between predicted tumour size and pathologically determined tumour size were 0.65 for clinical examination, 0.69 for mammography, 0.78 for sonography and 0.97 for MRI. Agreement between the response predictions at mid-treatment and the responses measured by pathology had kappa values of 0.28 for clinical examination, 0.32 for mammography, 0.46 for sonography and 0.68 for MRI. Agreement between the final response predictions and the responses measured by pathology had kappa values of 0.43 for clinical examination, 0.44 for mammography, 0.50 for sonography and 0.82 for MRI.

CONCLUSION

Predictions of response and residual tumour size made on MRI were better correlated with the assessments of response and residual tumour size made upon pathology than were predictions made on the basis of clinical examination, mammography or sonography. Thus, the evaluation of predicted response using MRI could provide a relatively sensitive early assessment of chemotherapy efficacy.

Reconstitution of gloeobacter rhodopsin with echinenone: role of the 4-keto group

In previous work, we reconstituted salinixanthin, the C(40)-carotenoid acyl glycoside that serves as a light-harvesting antenna to the light-driven proton pump xanthorhodopsin, into a different protein, gloeobacter rhodopsin expressed in Escherichia coli, and demonstrated that it transfers energy to the retinal chromophore [Imasheva, E. S., et al. (2009) Biochemistry 48, 10948]. The key to binding of salinixanthin was the accommodation of its ring near the retinal β-ionone ring. Here we examine two questions. Do any of the native Gloeobacter carotenoids bind to gloeobacter rhodopsin, and does the 4-keto group of the ring play a role in binding? There is no salinixanthin in Gloeobacter violaceous, but a simpler carotenoid, echinenone, also with a 4-keto group but lacking the acyl glycoside, is present in addition to β-carotene and oscillol. We show that β-carotene does not bind to gloeobacter rhodopsin, but its 4-keto derivative, echinenone, does and functions as a light-harvesting antenna. This indicates that the 4-keto group is critical for carotenoid binding. Further evidence of this is the fact that salinixanthol, an analogue of salinixanthin in which the 4-keto group is reduced to hydroxyl, does not bind and is not engaged in energy transfer. According to the crystal structure of xanthorhodopsin, the ring of salinixanthin in the binding site is turned out of the plane of the polyene conjugated chain. A similar conformation is expected for echinenone in the gloeobacter rhodopsin. We suggest that the 4-keto group in salinixanthin and echinenone allows for the twisted conformation of the ring around the C6-C7 bond and probably is engaged in an interaction that locks the carotenoid in the binding site.

Immune regulatory effects of simvastatin on regulatory T cell-mediated tumour immune tolerance

Statins are potent inhibitors of hydroxyl-3-methylglutaryl co-enzyme A (HMG-CoA) reductase, and have emerged as potential anti-cancer agents based on preclinical evidence. In particular, compelling evidence suggests that statins have a wide range of immunomodulatory properties. However, little is known about the role of statins in tumour immune tolerance. Tumour immune tolerance involves the production of immunosuppressive molecules, such as interleukin (IL)-10, transforming growth factor (TGF)-beta and indoleamine-2,3-dioxygenase (IDO) by tumours, which induce a regulatory T cell (T(reg)) response. In this study, we investigated the effect of simvastatin on the production of IL-10, TGF-beta and IDO production and the proliferation of T(regs) using several cancer cell lines, and Lewis lung cancer (3LL) cells-inoculated mouse tumour model. Simvastatin treatment resulted in a decrease in the number of cancer cells (3LL, A549 and NCI-H292). The production of the immune regulatory markers IL-10, TGF-beta in 3LL and NCI-H292 cells increased after treatment with simvastatin. The expression of IDO and forkhead box P3 (FoxP3) transcription factor was also increased in the presence of simvastatin. In a murine 3LL model, there were no significant differences in tumour growth rate between untreated and simvastatin-treated mice groups. Therefore, while simvastatin had an anti-proliferative effect, it also exhibited immune tolerance-promoting properties during tumour development. Thus, due to these opposing actions, simvastatin had no net effect on tumour growth.

Engineering an inward proton transport from a bacterial sensor rhodopsin

ATP is synthesized by an enzyme that utilizes proton motive force, and thus, nature has created various proton pumps. The best-understood proton pump is bacteriorhodopsin (BR), an outward-directed, light-driven proton pump in Halobacterium salinarum. Many archaeal and eubacterial rhodopsins are now known to show similar proton transport activity. We previously converted BR into an inward-directed chloride ion pump, but an inward proton pump has never been created. Proton pumps must have a specific mechanism to exclude transport in the reverse direction in order to maintain a proton gradient, and in the case of BR, a highly hydrophobic cytoplasmic domain may constitute such machinery. Here we report that an inward-directed proton transport can be engineered from a bacterial rhodopsin by a single amino acid replacement. Anabaena sensory rhodopsin (ASR) is a photochromic sensor in freshwater cyanobacteria that possesses little proton pump activity. When we replaced Asp217 in the cytoplasmic domain (a distance of approximately 15 A from the retinal chromophore) by Glu, ASR exhibited an inward proton transport activity driven by absorption of a single photon. FTIR spectra clearly showed an increased proton affinity for Glu217, which presumably controls the unusual directionality opposite to that in normal proton pumps.