Purpose

The effects of body mass index on pathologic complete response and survival have not been reported in Korean patients with breast cancer. The purpose of this study was to evaluate the predictive or prognostic value of obesity in breast cancer receiving neoadjuvant chemotherapy.

Methods

A total of 438 stage II or III breast cancer patients treated with neoadjuvant chemotherapy were enrolled and analyzed retrospectively.

Results

In the study, 319 patients (72.8%) were normal weight, 100 patients (22.8%) were overweight, and 19 patients (4.3%) were obese. Baseline clinicopathologic characteristics were not different among the groups, except for age. There were no differences in pathologic complete response rate between the groups (9.7% in normal weight, 10.0% in overweight, 5.3% in obese; p=0.804). Neither overweight nor obese patients showed a significant difference in relapse-free survival compared to normal weight patients (p=0.523 and p=0.931, respectively). Also, no significant difference in overall survival (p=0.520 and p=0.864, respectively) was observed.

Conclusion

Obesity or higher body mass index was not significantly associated with pathologic complete response and survival in Korean patients with breast cancer who received neoadjuvant chemotherapy. Our results suggest that the prognostic impact of body mass index is different from that of Western patients.

Background

To evaluate efficacy in patients with brain metastasis (BM) on entry into the lapatinib expanded access program (LEAP).

Methods

LEAP is a worldwide, single-arm, open-label study. HER2-positive, locally-advanced or metastatic breast cancer patients with progression after an anthracycline, taxane, and trastuzumab were eligible. Patients received capecitabine 2000 mg/m2 daily in two divided doses, days 1–14, every 21 days and lapatinib 1250 mg once daily.

Results

Among 186 patients enrolled in 6 Korean centers, 58 had BM. Progression-free survival (PFS) was 18.7 weeks in patients with BM and 19.4 weeks without BM (P = 0.88). In patients with BM, brain response was synchronized with systemic responses (P = 0.0001). Overall survival (OS) was 48.9 weeks in patients with BM and 64.6 weeks without BM (P = 0.23). Multivariable analysis found hormone receptor positivity (P = 0.003) and clinical benefit rate (CBR) of combined systemic and brain disease (P < 0.0001) significantly associated with prolonged brain PFS, and CBR of combined systemic and brain disease (P = 0.03) and longer trastuzumab use (P = 0.047) associated with prolonged OS in patients with BM; prior capecitabine did not affect PFS or OS in patients with BM.

Conclusion

Lapatinib plus capecitabine is equally effective in patients with or without BM.

Trial registration

ClinicalTrials.gov (NCT00338247)

Aberrations of Phosphoinositide 3-kinase (PI3K)/AKT signaling are frequently observed in many types of cancer, promoting its emergence as a promising target for cancer treatment. PI3K can become activated by various pathways, one of which includes RAS. RAS can not only directly activate the PI3K/AKT pathway via binding to p110 of PI3K, but also regulates mTOR via ERK or RSK independently of the PI3K/AKT pathway. Thus, actively mutated RAS can constitutively activate PI3K signaling. Additionally, in RAS tumorigenic transformation, signal transducer and activator of transcription 3 (STAT3) has been known also to be required. In this study, we examined the efficacy of NVP-BKM120, a pan-class I PI3K inhibitor in human gastric cancer cells and hypothesized that the combined inhibition of PI3K and STAT3 would be synergistic in KRAS mutant gastric cancer cells. NVP-BKM120 demonstrated anti-proliferative activity in 11 human gastric cancer cell lines by decreasing mTOR downstream signaling. But NVP-BKM120 treatment increased p-AKT by subsequent abrogation of feedback inhibition by stabilizing insulin receptor substrate-1. In KRAS mutant gastric cancer cells, either p-ERK or p-STAT3 was also increased upon treatment of NVP-BKM120. The synergistic efficacy study demonstrated that dual PI3K and STAT3 blockade showed a synergism in cells harboring mutated KRAS by inducing apoptosis. The synergistic effect was not seen in KRAS wild-type cells. Together, these findings suggest for the first time that the dual inhibition of PI3K and STAT3 signaling may be an effective therapeutic strategy for KRAS mutant gastric cancer patients.

Numerous studies have attempted to identify gene expression profiles which can be utilized to predict responses to neoadjuvant chemotherapy (NAC), but their findings are not clinically applicable at present. In the present study, we sought to determine DNA copy number alterations (CNAs) in breast cancer tissues which are associated with the response to NAC. Frozen tumor tissues from 63 breast cancer patients were obtained using core needle biopsy prior to NAC (3 cycles of docetaxel plus adriamycin) and were microdissected. Array comparative genomic hybridization (array CGH) with 4,045 bacterial artificial chromosome (BAC) probes was performed to identify the CNAs. Changes in tumor size in response to NAC were measured via magnetic resonance imaging. Fluorescence in situ hybridization (FISH) was conducted to verify array CGH results and for independent validation studies. CNAs at eight chromosomal loci encompassing 24 clones were correlated with changes in tumor size after NAC (p<0.05; t-test). Two CNAs were selected, 17p12 deletion and 17q21.32-33 gain, which were significantly associated with a smaller reduction in tumor size following NAC, via prioritization of the regions containing the candidate genes. In an independent validation set of samples from 39 patients, FISH assay further showed that the 17p12 deletion was markedly associated with smaller changes in tumor size (p=0.006), while the 17q21.32-33 gain was not significant (p=0.309). In conclusion, we successfully identified a 17p12 deletion in breast cancer tissue which can be applied in predicting tumor resistance to NAC.

Background

Gastric hepatoid adenocarcinoma (HAC) is a special type of gastric cancer that morphologically mimics hepatocellular carcinoma. In this study, we performed an evaluation of clinicopathologic characteristics, treatment outcome, and prognosis in patients with gastric HAC.

Methods

We consecutively enrolled patients with pathologically proven gastric HAC at Seoul National University Hospital between January 1996 and December 2008 and conducted a retrospective review. Among 15,253 patients with gastric cancer, 26 patients (0.17%) were diagnosed as gastric HAC.

Results

Among 26 patients, 22 were male and the median age was 63. Stage at diagnosis was stage IB in 3 patients, stage II in 6 patients, stage III in 7 patients, and stage IV in 10 patients. Eight patients out of 18 patients with stage IB, II, III, and IV relapsed after curative surgery. Relapse-free survival for these patients was 16.67 months. The most common metastatic site was intraabdominal lymph nodes (n = 9), followed by the liver (n = 8). Thirteen patients received palliative chemotherapy. The most commonly used regimen was a combination of fluoropyrimidine and platinum. Partial response was observed in one patient and stable disease in 5 patients. Median overall survival and progression free survival of these patients were 8.03 (95% CI: 6.59-9.47) and 3.47 months (95% CI: 0.65-6.29), respectively.

Conclusions

Gastric HAC is a very rare but unique type of stomach cancer. Early detection of this type of cancer is of critical importance to patient prognosis. Additional studies to reveal the biology of this tumor are warranted.

Prognostic value of p53 and bcl-2 expression on treatment outcome in breast cancer patients has been extensively evaluated, but the results were inconclusive. We evaluated the prognostic significance of these molecular markers in patients treated with breast conserving surgery and radiotherapy. One hundred patients whose immunostaining of p53 and bcl-2 expression was available among 125 patients who underwent radiotherapy after breast conserving surgery and axillary lymph node dissection were enrolled into this study. Eighty-seven patients also received adjuvant chemotherapy and/or hormonal therapy. Conventional clinicopathologic variables and treatment-related factors were also considered. The 5-yr loco-regional relapse-free and distant metastasis-free survival rates were 91.7% and 90.9%, respectively. On univariate analysis, age, T stage and the absence of bcl-2 & estrogen receptor (ER) expression were associated with loco-regional relapse-free survival. When incorporating these variables into Cox proportional hazard model, only bcl-2(-)/ER(-) phenotype was an adverse prognostic factor (P=0.018). As for the distant metastasis-free survival, age, T stage, and p53 expression were significant on univariate analysis. However, p53 expression was the only prognosticator on multivariate analysis (P=0.009). A bcl-2(-)/ER(-) phenotype and p53 expression are useful molecular markers predicting loco-regional relapse-free and distant metastasis-free survival, respectively, in patients treated with breast conserving surgery and radiotherapy.

We evaluated the efficacy and safety of weekly paclitaxel plus trastuzumab as firs-tline chemotherapy in women with HER2-overexpressing metastatic breast cancer (MBC), and we investigated the prognostic factors including magnitude of HER2/neu amplification in this population. We analyzed 54 patients with HER2-overexpressing MBC that were treated with weekly paclitaxel plus trastuzumab as first-line chemotherapy from February 2004 to December 2006. At a median follow-up of 28 months, median time to progression (TTP) was 16.6 months (95% CI, 9.4 to 23.7 months) and median overall survival was 25.6 months (95% CI, 21.8 to 27.3 months). Therapy was generally well tolerated, although three patients (5.5%) experienced reversible, symptomatic heart failure. Of the 27 patients evaluable for the HER2 FISH, patients with a HER2/CEP17 ratio of ≤4.0 had significantly shorter TTP than those with a HER2/CEP17 ratio of >4.0 (10.8 vs. 23.2 months, P=0.034). A HER2/CEP17 ratio of >4.0 was identified as significant predictive factor of TTP by multivariate analysis (P=0.032). The combination of weekly paclitaxel plus trastuzumab as first-line chemotherapy is an effective regimen in patients with HER2-FISH-positive MBC. Furthermore, the magnitude of HER2 amplification is an independent predictive factor of TTP.

Tinnitus-the perception of sound in the absence of an actual external sound-represents a symptom of an underlying condition rather than a single disease. Several theories have been proposed to explain the mechanisms underlying tinnitus. Tinnitus generators are theoretically located in the auditory pathway, and such generators and various mechanisms occurring in the peripheral auditory system have been explained in terms of spontaneous otoacoustic emissions, edge theory, and discordant theory. Those present in the central auditory system have been explained in terms of the dorsal cochlear nucleus, the auditory plasticity theory, the crosstalk theory, the somatosensory system, and the limbic and autonomic nervous systems. Treatments for tinnitus include pharmacotherapy, cognitive and behavioral therapy, sound therapy, music therapy, tinnitus retraining therapy, massage and stretching, and electrical suppression. This paper reviews the characteristics, causes, mechanisms, and treatments of tinnitus.

We previously reported that trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, induced DLC-1 mRNA expression and accumulated acetylated histones H3 and H4 associated with the DLC-1 promoter in DLC-1 non-expressing gastric cancer cells. In this study, we demonstrated the molecular mechanisms by which TSA induced the DLC-1 gene expression. Treatment of the gastric cancer cells with TSA activates the DLC-1 promoter activity through Sp1 sites located at -219 and -174 relative to the transcription start site. Electrophoretic mobility-shift assay (EMSA) revealed that Sp1 and Sp3 specifically interact with these Sp1 sites and showed that TSA did not change their binding activities. The ectopic expression of Sp1, but not Sp3, enhances the DLC-1 promoter responsiveness by TSA. Furthermore, the TSA-induced DLC-1 promoter activity was increased by p300 expression and reduced by knockdown of p300. These results demonstrated the requirement of specific Sp1 sites and dependence of Sp1 and p300 for TSA-mediated activation of DLC-1 promoter.

Background

There is no standard palliative chemotherapy regimen in biliary tract cancers (BTC). Fluoropyrimidine or gemcitabine, with or without platinum, are most frequently used. We conducted this study to clarify the efficacy of palliative chemotherapy in BTC.

Methods

Patients with unresectable BTC treated with palliative chemotherapy between Oct 2001 and Aug 2006 at Seoul National University Hospital were reviewed retrospectively. Histologically confirmed cases of intrahepatic cholangiocarcinoma, gallbladder cancer, extrahepatic bile duct cancer, and ampulla of Vater carcinoma were enrolled. We analyzed the efficacy of regimens: gemcitabine (G) versus fluoropyrimidine (F) and with or without platinum (P).

Results

A total of 243 patients were enrolled. 159 patients (65%) were male and the median age of the patients was 60 years (range 26–81). Intrahepatic cholangiocarcinoma, gallbladder cancer, extrahepatic bile duct cancer, and ampulla of Vater carcinoma were 92, 72, 58, and 21 cases, respectively. The median progression free survival (PFS) was 4.3 months (95% CI, 3.7–4.9) and median overall survival (OS) was 8.7 months (95% CI, 7.4–10.0). Ninety-nine patients received G-based chemotherapy (94 GP, 5 G alone), and 144 patients received F-based chemotherapy (83 FP, 61 F alone). The response rate (RR), disease control rate (DCR), PFS and OS of G-based chemotherapy versus F-based chemotherapy were 16.7% vs. 19.5% (P = 0.591), 52.8% vs. 58.9% (P = 0.372), 4.0 months vs. 4.3 months (P = 0.816), and 7.8 months vs. 9.1 months (P = 0.848), respectively. Sixty-six patients received F or G without P, and 177 patients received F or G with P. The RR, DCR, PFS and OS of chemotherapy without P versus chemotherapy including P were 12.7% vs. 20.6% (P = 0.169), 46.0% vs. 60.6% (P = 0.049), 3.3 months vs. 4.4 months (P = 0.887), and 10.6 months vs. 8.1 months (P = 0.257), respectively.

Conclusion

In unresectable BTC, F-based and G-based chemotherapy showed similar efficacy in terms of RR, DCR, PFS and OS. The benefit of adding P to F or G was not significant except for DCR. Further prospective studies which define the efficacy of various chemotherapeutic regimens in BTC are warranted.

Hypoxia-inducible factor 1α (HIF-1α) is rapidly degraded by the ubiquitin-proteasome pathway under normoxic conditions. Ubiquitination of HIF-1α is mediated by interaction with von Hippel-Lindau tumor suppressor protein (pVHL). In our previous report, we found that hypoxia-induced active signal transducer and activator of transcription3 (STAT3) accelerated the accumulation of HIF-1α protein and prolonged its half-life in solid tumor cells. However, its specific mechanisms are not fully understood. Thus, we examined the role of STAT3 in the mechanism of pVHL-mediated HIF-1α stability. We found that STAT3 interacts with C-terminal domain of HIF-1α and stabilizes HIF-1α by inhibition of pVHL binding to HIF-1α. The binding between HIF-1α and pVHL, negative regulator of HIF-1α stability, was interfered dose-dependently by overexpressed constitutive active STAT3. Moreover, we found that the enhanced HIF-1α protein levels by active STAT3 are due to decrease of poly-ubiquitination of HIF-1α protein via inhibition of interaction between pVHL and HIF-1α. Taken together, our results suggest that STAT3 decreases the pVHL-mediated ubiquitination of HIF-1α through competition with pVHL for binding to HIF-1α, and then stabilizes HIF-1α protein levels.

This study was performed to evaluate the efficacy and toxicity of low-dose paclitaxel/cisplatin chemotherapy in patients with metastatic or recurrent gastric cancer that had failed 5-fluorouracil/platinum-based chemotherapy. Thirty-two patients with documented progression on or within 6 months after discontinuing 5-fluorouracil/platinum-based chemotherapy were enrolled. As a second-line treatment, paclitaxel (145 mg/m2) and cisplatin (60 mg/m2) was administered on day 1 every 3 weeks. Among 32 patients enrolled, 8 (25%) responded partially to paclitaxel/cisplatin, 8 (25%) had stable disease, and 14 (44%) had progressive disease. Two patients (6%) were not evaluable. The median time to progression (TTP) and overall survival for all patients were 2.9 months and 9.1 months, respectively. The most common hematologic toxicity was anemia (47%). Grade 3 neutropenia developed in three patients (9%), but no other grade 3/4 hematologic toxicity occurred. The most common non-hematologic toxicities were emesis (31%) and peripheral neuropathy (38%). Three cases (9%) of grade 3/4 emesis and 2 cases (6%) of grade 3 peripheral neuropathy developed. In conclusion, low-dose paclitaxel and cisplatin chemotherapy showed moderate activity with favorable toxicity profiles. However, relatively short TTP of this regimen warrants the development of more effective paclitaxel-based regimens other than combination with cisplatin in these patients as second-line therapies.

Despite advances in the characterization of anaplastic large cell lymphoma (ALCL), little data is available on Asian patients. We report here upon single Korean institution's experience regarding the clinical characteristics and outcomes of ALCL. We performed a retrospective study of 32 adults with ALCL. Most of the patients received anthracycline-based chemotherapy. Ann Arbor stage III-IV, B symptoms, high-intermediate/high International Prognostic Index (IPI), and extranodal disease at diagnosis were present in 56%, 44%, 41%, and 63%, respectively. Compared with Western studies, the male/female ratio (4.3) was markedly higher and skin (9%) and bone involvement (9%) were less frequent. The staining results for anaplastic lymphoma kinase were positive in 6 (33%) of 18 cases available. The complete response (CR) rate was 62% (95% CI, 44-80%). With a median follow-up of 51.0 months, 5 yr overall survival was 40±11%. The 3 yr relapse-free survival for the 18 patients who achieved CR was 74±12%. Age, performance status, lactate dehydrogenase, extranodal disease sites number, and IPI were correlated with treatment response and survival. Our data suggest that Korean ALCL patients appear to have a higher male/female ratio, less frequent skin/bone involvement, and lower CR rate compared with those of Western studies.

Purpose

We wanted to demonstrate the anti-cancer effect and interaction between belotecan and cisplatin on gastric cancer cell line and we evaluated the mechanisms of this synergistic effect in vitro.

Materials and Methods

The growth inhibitory effect of belotocan and cisplatin against several gastric cancer cell lines (SNU-5, SNU-16 and SNU-601) was estimated by tetrazolium dye assay. The effect of a combination treatment was evaluated by the isobologram method. The biochemical mechanisms for the interaction between the drugs were analyzed by measuring the formation of DNA interstrand cross-links (ICLs) and DNA topo-I activity.

Results

Belotecan showed synergism with cisplatin for growth inhibitory effect on the gastric cancer cell lines SNU-5, and SNU-16, but this was subadditive on the SNU-601 cell line. The formation of DNA ICLs in SNU-16 cells by cisplatin was increased by combination with belotecan, but this was not affected in SNU-601 cells. The topo-I inhibition by belotecan was enhanced at high concentrations of cisplatin in SNU-16, but not in SNU-601 cells.

Conclusion

Belotecan and cisplatin show various combination effect against gastric cancer cells. The synergism between cisplatin and belotecan could be the result of one of the following mechanisms: the modulating effect of belotecan on the repair of cisplatin-induced DNA adducts and the enhancing effect of cisplatin on the belotecan-induced topo-I inhibitory effect.

Although Smad2 and Smad3, critical transcriptional mediators of transforming growth factor-β (TGF-β) signaling, are supposed to play a role in the TGF-β cytostatic program, it remains unclear whether TGF-β delivers cytostatic signals through both Smads equally or through either differentially. Here, we report that TGF-β cytostatic signals rely on a Smad3-, but not a Smad2-, dependent pathway and that the intensity of TGF-β cytostatic signals can be modulated by changing the endogenous ratio of Smad3 to Smad2. Depleting endogenous Smad3 by RNA interference sufficiently interfered with TGF-β cytostatic actions in various TGF-β-sensitive cell lines, whereas raising the relative endogenous ratio of Smad3 to Smad2, by depleting Smad2, markedly enhanced TGF-β cytostatic response. Consistently, Smad3 activation and its transcriptional activity upon TGF-β stimulation were facilitated in Smad2-depleted cells relative to controls. Most significantly, a single event of increasing this ratio by Smad2 depletion was sufficient to restore TGF-β cytostatic action in cells resistant to TGF-β. These findings suggest a new important determinant of sensitivity to TGF-β cytostatic signaling.

To evaluate the toxicity and efficacy of a reduced dose intensity (mini-) FOLFOX-4 regimen as a first-line palliative chemotherapy in elderly patients (≥70 yr of age) with advanced colorectal cancer, data from prospective databases at Seoul National University Bundang Hospital and Seoul Municipal Boramae Hospital were analyzed. A total of 20 patients were enrolled between January 2001 and August 2004, and were treated with oxaliplatin 65 mg/m2 on day 1, and with 2-hr infusions of leucovorin 150 mg/m2 followed by a 5-FU bolus (300 mg/m2) and 22-hr continuous infusions (450 mg/m2) for 2 consecutive days every 2 weeks until progression, unacceptable toxicity or patient refusal. Sixteen patients were evaluable for response with an overall response rate of 43.8%. Median progression-free survival was 4.8 months (95% CI: 3.0-6.7) and overall survival was 13.5 months (95% CI: 11.1-16.0). The main side effects were anemia and neutropenia, which were observed in 20.8% and 17.7%, respectively, of the total cycles administered. There were no grade 4 toxicities and only one patient suffered from febrile neutropenia. No grade 3 toxicities occurred except for anemia (5.2%) and vomiting (1.0%). In conclusion, the mini-FOLFOX-4 regimen was found to be well tolerated with acceptable toxicity, and to provide a benefit for elderly patients with colorectal cancer.

Integrin-mediated cell adhesion and spreading enables cells to respond to extracellular stimuli for cellular functions. Using a gastric carcinoma cell line that is usually round in adhesion, we explored the mechanisms underlying the cell spreading process, separate from adhesion, and the biological consequences of the process. The cells exhibited spreading behavior through the collaboration of integrin-extracellular matrix interaction with a Smad-mediated transforming growth factor β1 (TGFβ1) pathway that is mediated by protein kinase Cδ (PKCδ). TGFβ1 treatment of the cells replated on extracellular matrix caused the expression and phosphorylation of PKCδ, which is required for expression and activation of integrins. Increased expression of integrins α2 and α3 correlated with the spreading, functioning in activation of focal adhesion molecules. Smad3, but not Smad2, overexpression enhanced the TGFβ1 effects. Furthermore, TGFβ1 treatment and PKCδ activity were required for increased motility on fibronectin and invasion through matrigel, indicating their correlation with the spreading behavior. Altogether, this study clearly evidenced that the signaling network, involving the Smad-dependent TGFβ pathway, PKCδ expression and phosphorylation, and integrin expression and activation, regulates cell spreading, motility, and invasion of the SNU16mAd gastric carcinoma cell variant.

Purpose

The aim of this study is to compare the antiemetic efficacy and tolerability of intravenous dolasetron mesylate and ondansetron in the prevention of acute and delayed emesis.

Material and Methods

From April 2002 through October 2002, a total of 112 patients receiving cisplatin- based combination chemotherapy were randomized to receive a single i.v. dose of dolasetron 100 mg or ondansetron 8 mg, 30 minutes before the initiation of chemotherapy. In the ondansetron group, two additional doses of ondansetron 8 mg were given at intervals of 2 to 4 hours. To prevent delayed emesis, dolasetron 200 mg p.o. daily or ondansetron 8 mg p.o. bid was administered from the 2nd days to a maximum of 5 days. The primary end point was the proportion of patients that experienced no emetic episodes and required no rescue medication (complete response, CR) during the 24 hours (acute period) and during Day 2 to Day 5±2 days (delayed period), after chemotherapy. The secondary end points included the incidence and severity of emesis.

Results

105 patients were evaluable for efficacy. CR rates during the acute period were 36.0% for a single dose of dolasetron 100 mg, and 43.6% for three doses of ondansetron 8 mg. CR rates during the delayed period were 8.0% and 10.9%, respectively. There was no significant difference in the efficacy between the two groups. Adverse effects were mostly mild to moderate and not related to study medication.

Conclusions

A single i.v. dose of dolasetron 100 mg is as effective as three i.v. doses of ondansetron 8 mg in preventing acute and delayed emesis after cisplatin-based chemotherapy, with a comparable safety profile.

To date, two major apoptotic pathways, the death receptor and the mitochondrial pathway, have been well documented in mammalian cells. However, the involvement of these two apoptotic pathways, particularly the death receptor pathway, in transforming growth factor-β1 (TGF-β1)-induced apoptosis is not well understood. Herein, we report that apoptosis of human gastric SNU-620 carcinoma cells induced by TGF-β1 is caused by the Fas death pathway in a Fas ligand-independent manner, and that the Fas death pathway activated by TGF-β1 is linked to the mitochondrial apoptotic pathway via Bid mediation. We showed that TGF-β1 induced the expression and activation of Fas and the subsequent caspase-8-mediated Bid cleavage. Interestingly, expression of dominant negative FADD and treatment with caspase-8 inhibitor efficiently prevented TGF-β1-induced apoptosis, whereas the treatment with an activating CH11 or a neutralizing ZB4 anti-Fas antibody, recombinant Fas ligand, or Fas-Fc chimera did not affect activation of Fas and the subsequent induction of apoptosis by TGF-β1. We further demonstrated that TGF-β1 also activates the mitochondrial pathway showing Bid-mediated loss of mitochondrial membrane potential and subsequent cytochrome c release associated with the activations of caspase-9 and the effector caspases. Moreover, all these apoptotic events induced by TGF-β1 were found to be effectively inhibited by Smad3 knockdown and also completely abrogated by Smad7 expression, suggesting the involvement of the Smad3 pathway upstream of the Fas death pathway by TGF-β1.

Different cyclins mediate different cell-cycle transitions. Some cyclins, such as cyclin A and cyclin E, form stable complexes with proteins that bind directly or indirectly to DNA and thus might be recruited to certain regions of the genome at specific times in the cell cycle. Furthermore, cyclins contain structural motifs that are also present in known transcriptional modulators. We found that cyclin A is a potent transcriptional repressor and cyclin E is a potent transcriptional activator when bound to DNA via a heterologous DNA binding domain. The former activity was linked to the integrity of the cyclin A cyclin fold, whereas the latter activity related to the ability of cyclin E to activate cdk2 and recognize substrates. Furthermore, we found that cyclin E, but not cyclin A, activated transcription in a cell-cycle–dependent manner when present in physiological concentrations as an unfused protein. These results suggest that cyclin A and cyclin E intrinsically differ with respect to their ability to modulate transcription when tethered to DNA.

Background

Lapatinib plus capecitabine is an effective treatment option for trastuzumab-refractory HER2-positive metastatic breast cancer. We have investigated the correlation between quantitative measures of HER2, p95HER2, and HER3 and treatment outcomes using lapatinib and capecitabine.

Methods

Total HER2 (H2T), p95HER2 (p95), and total HER3 (H3T) expression were quantified in formalin-fixed paraffin-embedded samples using the VeraTag assays. Patients received lapatinib and capecitabine treatment following trastuzumab failure according to the Lapatinib Expanded Access Program. The association between the protein expression levels and clinical outcomes was analyzed.

Results

A total of 52 patients were evaluable. H2T level was significantly higher in responders (median 93.49 in partial response, 47.66 in stable disease, and 17.27 in progressive disease; p = 0.020). Longer time-to-progression (TTP) was observed in patients with high H2T [p = 0.018, median 5.2 months in high (>14.95) vs. 1.8 in low (<14.95)] and high H3T [p = 0.017, median 5.0 months in high (>0.605) vs. 2.2 in low (<0.605)]. Patients having both high H2T and high H3T had significantly longer TTP [adjusted hazard ratio (HR) 0.38 (95% CI 0.20–0.73), p = 0.004] and overall survival [adjusted HR 0.46 (95% CI 0.24–0.89), p = 0.020]. No significant association between p95 and response or survival was observed.

Conclusions

These data suggest a correlation between high HER2 and high HER3 expression and treatment outcome, while no significant difference was observed between clinical outcome and p95 expression level in this cohort of HER2-positive, trastuzumab-refractory metastatic breast cancer patients treated with lapatinib and capecitabine.

The N-end rule pathway is a proteolytic system in which its recognition components (N-recognins) recognize destabilizing N-terminal residues of short-lived proteins as an essential element of specific degrons, called N-degrons. The RING E3 ligases UBR2 and UBR1 are major N-recognins that share size (200 kDa), conserved domains and substrate specificities to N-degrons. Despite the known function of the N-end rule pathway in degradation of cytosolic proteins, the major phenotype of UBR2-deficient male mice is infertility caused by arrest of spermatocytes at meiotic prophase I. UBR2-deficient spermatocytes are impaired in transcriptional silencing of sex chromosome-linked genes and ubiquitylation of histone H2A. In this study we show that the recruitment of UBR2 to meiotic chromosomes spatiotemporally correlates to the induction of chromatin-associated ubiquitylation, which is significantly impaired in UBR2-deficient spermatocytes. UBR2 functions as a scaffold E3 that promotes HR6B/UbcH2-dependent ubiquitylation of H2A and H2B but not H3 and H4, through a mechanism distinct from typical polyubiquitylation. The E3 activity of UBR2 in histone ubiquitylation is allosterically activated by dipeptides bearing destabilizing N-terminal residues. Insufficient monoubiquitylation and polyubiquitylation on UBR2-deficient meiotic chromosomes correlate to defects in double strand break (DSB) repair and other meiotic processes, resulting in pachytene arrest at stage IV and apoptosis. Some of these functions of UBR2 are observed in somatic cells, in which UBR2 is a chromatin-binding protein involved in chromatin-associated ubiquitylation upon DNA damage. UBR2-deficient somatic cells show an array of chromosomal abnormalities, including hyperproliferation, chromosome instability, and hypersensitivity to DNA damage-inducing reagents. UBR2-deficient mice enriched in C57 background die upon birth with defects in lung expansion and neural development. Thus, UBR2, known as the recognition component of a major cellular proteolytic system, is associated with chromatin and controls chromatin dynamics and gene expression in both germ cells and somatic cells.

Background

Identification of predictive biomarkers is essential for the successful development of targeted therapy. Insulin-like growth factor 1 receptor (IGF1R) has been examined as a potential therapeutic target for various cancers. However, recent clinical trials showed that anti-IGF1R antibody and chemotherapy are not effective for treating lung cancer.

Methodology/Principal Findings

In order to define biomarkers for predicting successful IGF1R targeted therapy, we evaluated the anti-proliferation effect of figitumumab (CP-751,871), a humanized anti-IGF1R antibody, against nine gastric and eight hepatocellular cancer cell lines. Out of 17 cancer cell lines, figitumumab effectively inhibited the growth of three cell lines (SNU719, HepG2, and SNU368), decreased p-AKT and p-STAT3 levels, and induced G 1 arrest in a dose-dependent manner. Interestingly, these cells showed co-overexpression and altered mobility of the IGF1R and insulin receptor (IR). Immunoprecipitaion (IP) assays and ELISA confirmed the presence of IGF1R/IR heterodimeric receptors in figitumumab-sensitive cells. Treatment with figitumumab led to the dissociation of IGF1-dependent heterodimeric receptors and inhibited tumor growth with decreased levels of heterodimeric receptors in a mouse xenograft model. We next found that both IGF1R and IR were N-linked glyosylated in figitumumab-sensitive cells. In particular, mass spectrometry showed that IGF1R had N-linked glycans at N913 in three figitumumab-sensitive cell lines. We observed that an absence of N-linked glycosylation at N913 led to a lack of membranous localization of IGF1R and figitumumab insensitivity.

Conclusion and Significance

The data suggest that the level of N-linked glycosylated IGF1R/IR heterodimeric receptor is highly associated with sensitivity to anti-IGF1R antibody in cancer cells.

Background

Epigenetic alteration of gene expression is a common event in human cancer. DNA methylation is a well-known epigenetic process, but verifying the exact nature of epigenetic changes associated with cancer remains difficult.

Methods

We profiled the methylome of human gastric cancer tissue at 50-bp resolution using a methylated DNA enrichment technique (methylated CpG island recovery assay) in combination with a genome analyzer and a new normalization algorithm.

Results

We were able to gain a comprehensive view of promoters with various CpG densities, including CpG Islands (CGIs), transcript bodies, and various repeat classes. We found that gastric cancer was associated with hypermethylation of 5' CGIs and the 5'-end of coding exons as well as hypomethylation of repeat elements, such as short interspersed nuclear elements and the composite element SVA. Hypermethylation of 5' CGIs was significantly correlated with downregulation of associated genes, such as those in the HOX and histone gene families. We also discovered long-range epigenetic silencing (LRES) regions in gastric cancer tissue and identified several hypermethylated genes (MDM2, DYRK2, and LYZ) within these regions. The methylation status of CGIs and gene annotation elements in metastatic lymph nodes was intermediate between normal and cancerous tissue, indicating that methylation of specific genes is gradually increased in cancerous tissue.

Conclusions

Our findings will provide valuable data for future analysis of CpG methylation patterns, useful markers for the diagnosis of stomach cancer, as well as a new analysis method for clinical epigenomics investigations.

Background

This study was aimed 1) to investigate the predictive value of FDG PET/CT (fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography) for histopathologic response and 2) to explore the results of FDG PET/CT by molecular phenotypes of breast cancer patients who received neoadjuvant chemotherapy.

Methods

Seventy-eight stage II or III breast cancer patients who received neoadjuvant docetaxel/doxorubicin chemotherapy were enrolled in this study. FDG PET/CTs were acquired before chemotherapy and after the first cycle of chemotherapy for evaluating early metabolic response.

Results

The mean pre- and post-chemotherapy standard uptake value (SUV) were 7.5 and 3.9, respectively. The early metabolic response provided by FDG PET/CT after one cycle of neoadjuvant chemotherapy was correlated with the histopathologic response after completion of neoadjuvant chemotherapy (P = 0.002). Sensitivity and negative predictive value were 85.7% and 95.1%, respectively. The estrogen receptor negative phenotype had a higher pre-chemotherapy SUV (8.6 vs. 6.4, P = 0.047) and percent change in SUV (48% vs. 30%, P = 0.038). In triple negative breast cancer (TNBC), the pre-chemotherapy SUV was higher than in non-TNBC (9.8 vs. 6.4, P = 0.008).

Conclusions

The early metabolic response using FDG PET/CT could have a predictive value for the assessment of histopathologic non-response of stage II/III breast cancer treated with neoadjuvant chemotherapy. Our findings suggest that the initial SUV and the decline in SUV differed based on the molecular phenotype.

Trial Registration

ClinicalTrials.gov: NCT01396655