Comparison of clinical outcomes between proximal and non-proximal right coronary artery occlusion in patients with inferior ST-segment elevation myocardial infarction.

BACKGROUND: The clinical outcomes of ST-segment elevation myocardial infarction (STEMI) due to the occlusion of left coronary artery are worse in patients with proximal occlusion than in those with non-proximal occlusion. However, there are few reports that focus on the comparison of clinical outcomes in patients with STEMI between proximal and non-proximal right coronary artery (RCA) occlusions. METHODS: We included 356 patients with STEMI whose infarct-related artery is RCA and divided them into the proximal group (n = 129) and the non-proximal group (n = 227). We defined segment 1 of RCA as proximal, and segments 2, 3, and 4 as non-proximal according to the reporting system of the American Heart Association. The primary endpoint was major cardiovascular events (MACE), which was defined as the composite of all-cause death, non-fatal myocardial infarction, readmission for heart failure, and ischemia-driven target vessel revascularization. RESULTS: Incidence of shock at admission, requirement for catecholamine during percutaneous coronary intervention (PCI), or mechanical support during PCI tended to be higher in the proximal group (42.6 %) than in the non-proximal group (33.5 %) (p = 0.088). Although the incidence of right ventricular infarction tended to be higher in the proximal group (17.8 %) than in the non-proximal group (10.6 %) without reaching statistical significance (p = 0.072), the incidence of in-hospital death was similar between the 2 groups (1.6 % versus 1.8 %, p = 1.000). The MACE-free survival curves were not different between the 2 groups (p = 0.400). Multivariate Cox hazard analysis revealed that proximal RCA occlusion was not associated with MACE (HR 1.095, 95%CI 0.691-1.737, p = 0.699). CONCLUSIONS: Although the acute phase conditions such as shock or right ventricular infarction tended to be more severe in patients with proximal occlusion, overall clinical outcomes including long-term outcomes were comparable between the proximal and distal RCA occlusions. Furthermore, multivariate analysis showed that the proximal RCA occlusion was not associated with MACE after hospital discharge.

Creatinine kinase-myocardial band (CK-MB) to creatinine kinase (CK) ratio for ST-segment elevation myocardial infarction in the era of the universal definition.

Although serum troponin level is the gold standard under the universal definition of acute myocardial infarction (AMI), serum creatinine kinase (CK) and creatine kinase-myocardial band (CK-MB) is still measured in clinical practice as the compliment of troponin level. The purpose of this retrospective study is to illustrate the dramatic change of CK-MB/CK ratio by comparing CK-MB/CK ratio in patients with ST-segment elevation myocardial infarction (STEMI) among ≤ 24 h before reaching peak CK, peak CK, ≤ 24 h after reaching peak CK, and 24-48 h after reaching peak CK. We included 502 patients with STEMI. We calculated each average CK-MB/CK ratio at ≤ 24 h before reaching peak CK, peak CK, ≤ 24 h after reaching peak CK, and 24-48 h after reaching peak CK. The average values were compared using Friedman test. The average CK-MB/CK ratio at ≤ 24 h before reaching peak CK, peak CK, ≤ 24 h after reaching peak CK, and 24-48 h after reaching peak CK was 0.096 (9.6% of CK), 0.098 (9.8% of peak CK), 0.076 (7.6% of CK), and 0.028 (2.8% of CK), respectively. The Friedman test suggested that the CK-MB/CK ratio significantly declined after reaching peak CK (p < 0.001). In conclusion, the CK-MB/CK ratio was around 0.1 (10% of CK) until CK-MB and CK reached the peak, but dropped sharply after reaching peak CK. The CK-MB/CK ratio less than 0.1 (10% of CK) cannot be used to rule out the possibility of AMI, when the onset of symptom is unclear or late presentation.

Determinants of serious in-hospital complications in patients with Killip class 1/2 ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention.

Killip classification has been used to stratify the risk of patients with acute myocardial infarction (AMI). There were many reports that Killip class 3 or 4 is closely associated with poor clinical outcomes. In other words, Killip class 1 or 2 is associated with favorable clinical outcomes in patients with AMI, especially when patients received primary percutaneous coronary intervention (PCI). However, some patients with Killip class 1/2 suffer from serious in-hospital complications. This study aimed to identify factors associated with serious in-hospital complications of ST-segment elevation myocardial infarction (STEMI) in patients with Killip class 1/2. The primary endpoint was serious in-hospital complications defined as the composite of in-hospital death and mechanical complications. We included 809 patients with STEMI, and divided them into the non-complication group (n = 791) and the complication group (n = 18). In-hospital death was observed in 14 patients (1.7%), and mechanical complications were observed in 4 patients (0.5%). Final TIMI flow ≤ 2 was more frequently observed in the complication group (33.3%) than in the non-complication group (5.4%) (p < 0.001). Multivariate logistic regression analysis revealed that serious in-hospital complication was associated with final TIMI flow grade ≤ 2 (Odds ratio 6.040, 95% confidence interval 2.042-17.870, p = 0.001). In conclusion, serious in-hospital complication of STEMI was associated with insufficient final TIMI flow grade in patients with Killip class 1/2. If final TIMI flow grade is suboptimal after primary PCI, we may recognize the potential risk of serious complications even when patients presented as Killip class 1/2.

Clinical Impact of In-Stent Calcification in Coronary Arteries: Optical Coherence Tomography Study.

In-stent restenosis with neoatherosclerosis has been known as the predictor of target lesion revascularization (TLR) after percutaneous coronary intervention. However, the impact of in-stent calcification (ISC) alone on clinical outcomes remains unknown since neoatherosclerosis by optical coherence tomography includes in-stent lipid and calcification. We aimed to assess the effect of ISC on clinical outcomes and clinical differences among different types of ISC. We included 126 lesions that underwent optical coherence tomography-guided percutaneous coronary intervention and divided those into the ISC group (n = 38) and the non-ISC group (n = 88) according to the presence of ISC. The cumulative incidence of clinically driven TLR (CD-TLR) was compared between the ISC and non-ISC groups. The impact of in-stent calcified nodule and nodular calcification on CD-TLR was evaluated using the Cox hazard model. The incidence of CD-TLR was significantly higher in the ISC group than in the non-ISC group (p = 0.004). In the multivariate Cox hazard model, ISC was significantly associated with CD-TLR (hazard ratio [HR] 3.58, 95% confidence interval [CI] 1.33 to 9.65, p = 0.01). In-stent calcified nodule/nodular calcification and in-stent nodular calcification alone were also the factors significantly associated with CD-TLR (HR 3.34, 95%CI 1.15 to 9.65, p = 0.03 and HR 5.21, 95%CI 1.82 to 14.91, p = 0.002, respectively). ISC without in-stent calcified nodule/nodular calcification, which was defined as in-stent smooth calcification, was not associated with CD-TLR. In conclusion, ISC was associated with a higher rate of CD-TLR. The types of calcifications that led to a high rate of CD-TLR were in-stent calcified nodule/nodular calcification and in-stent nodular calcification alone but not in-stent smooth calcification. In-stent calcified nodule and nodular calcification should be paid more attention.

Determinants of successful parallel wire technique in percutaneous coronary intervention to coronary chronic total occlusion.

BACKGROUND: Many techniques and concepts have been developed in the field of percutaneous coronary intervention to chronic total occlusion (CTO). Parallel wire technique (PWT) is still an important technique in antegrade approach. The purpose of this study was to identify the determinants of successful PWT in coronary CTO. METHODS: We reviewed consecutive 451 CTO lesions that were treated with PCI in our medical center. The overall success rate of PCI to CTO during the study period was 92.2 % (416/451). Of 451 CTO lesions, we excluded 333 CTO lesions in which PTW was not performed. We included 118 CTO lesions in which PWT was performed, and divided them into the successful PWT group (n = 65) and the unsuccessful PWT group (n = 53) according to the procedure success of PWT. Multivariate logistic regression analysis were performed to find the determinants of successful PWT. RESULTS: The prevalence of the sufficient clarity of CTO exit site was significantly higher in the successful PWT group (46.2 %) than in the unsuccessful PWT group (11.3 %) (p < 0.01). Multivariate logistic regression analysis revealed that the J-CTO score was inversely associated with successful PWT (OR 0.66, 95 % CI 0.44-0.99, P = 0.04), whereas the sufficient clarity of CTO exit site was associated with successful PWT (OR 5.16, 95 % CI 1.75-15.20, P < 0.01). CONCLUSIONS: The J-CTO score was inversely associated with successful PWT, whereas the sufficient clarity of CTO exit site was associated with successful PWT. The low J-CTO score and the sufficient clarity of CTO exit site may be the determinants of successful PWT.

Impact of controlled blood pressure and pulse rate at discharge on clinical outcomes in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Although major guidelines recommend the routine introduction of angiotensin-converting enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs) and beta-blockers for patients with ST-segment elevation myocardial infarction (STEMI), evidence regarding the target blood pressure (BP) or pulse rate (PR) at hospital discharge is sparse. This retrospective study aimed to compare the clinical outcomes in patients with STEMI between those with good BP and PR control and those with poor BP or PR control. METHODS: We included 748 patients with STEMI who received both ACE inhibitors/ARBs and beta-blockers at hospital discharge, and divided them into a good control group (systolic BP ≤140 mmHg and PR ≤80 bpm, n = 564) and a poor control group (systolic BP >140 mmHg or PR >80 bpm, n = 184). The primary endpoint was major cardiovascular events (MACE) defined as the composite of all-cause death, non-fatal myocardial infarction, and re-admission for heart failure. RESULTS: During the median follow-up duration of 568 days, a total of 119 MACE were observed. The Kaplan-Meier curves showed that MACE were more frequently observed in the poor control group (p = 0.009). In the multivariate Cox hazard analysis, the good control group was inversely associated with MACE (HR 0.656, 95 % CI: 0.444-0.968, p = 0.034) after controlling for multiple confounding factors. CONCLUSIONS: The good control of systolic BP and PR at discharge was inversely associated with long-term adverse events in STEMI patients treated with both ACE inhibitors/ARBs and beta blockers. This study suggests the importance of titration of ACE inhibitors/ARBs and beta-blockers for better clinical outcomes in patients with STEMI.

Development of a simple prediction model for mechanical complication in ST-segment elevation myocardial infarction patients after primary percutaneous coronary intervention.

Mechanical complication (MC) is a rare but serious complication in patients with ST-segment elevation myocardial infarction (STEMI). Although several risk factors for MC have been reported, a prediction model for MC has not been established. This study aimed to develop a simple prediction model for MC after STEMI. We included 1717 patients with STEMI who underwent primary percutaneous coronary intervention (PCI). Of 1717 patients, 45 MCs occurred after primary PCI. Prespecified predictors were determined to develop a tentative prediction model for MC using multivariable regression analysis. Then, a simple prediction model for MC was generated. Age ≥ 70, Killip class ≥ 2, white blood cell ≥ 10,000/µl, and onset-to-visit time ≥ 8 h were included in a simple prediction model as "point 1" risk score, whereas initial thrombolysis in myocardial infarction (TIMI) flow grade ≤ 1 and final TIMI flow grade ≤ 2 were included as "point 2" risk score. The simple prediction model for MC showed good discrimination with the optimism-corrected area under the receiver-operating characteristic curve of 0.850 (95% CI: 0.798-0.902). The predicted probability for MC was 0-2% in patients with 0-4 points of risk score, whereas that was 6-50% in patients with 5-8 points. In conclusion, we developed a simple prediction model for MC. We may be able to predict the probability for MC by this simple prediction model.

Association of Increased Inter-arm Blood Pressure Difference with Long-term Clinical Outcomes in Patients with Acute Myocardial Infarction Who Underwent Percutaneous Coronary Intervention.

Objective Patients with acute myocardial infarction (AMI) often have peripheral artery disease (PAD). It is well known that the long-term clinical outcomes of AMI are worse in patients with a low ankle-brachial index (ABI) than in patients with a preserved ABI. Unlike ABI, the association between the inter-arm blood pressure difference (IABPD) and clinical outcomes in patients with AMI has not yet been established. This retrospective study examined whether or not the IABPD is associated with long-term clinical outcomes in patients with AMI. Methods We included 979 patients with AMI and divided them into a high-IABPD group (IABPD ≥10 mmHg, n=31) and a low-IABPD group (IABPD <10 mmHg, n=948) according to the IABPD measured during hospitalization for AMI. The primary endpoint was the all-cause mortality rate. Results During a median follow-up duration of 694 days (Q1, 296 days; Q3, 1,281 days), 82 all-cause deaths were observed. Kaplan-Meier curves showed that all-cause death was more frequently observed in the high-IABPD group than in the low-IABPD group (p<0.001). A multivariate Cox hazard analysis revealed that a high IABPD was significantly associated with all-cause death (hazard ratio 2.061, 95% confidence interval 1.012-4.197, p=0.046) after controlling for multiple confounding factors. Conclusion A high IABPD was significantly associated with long-term all-cause mortality in patients with AMI. Our results suggest the usefulness of the IABPD as a prognostic marker for patients with AMI.

Impact of the Japanese Version of High Bleeding Risk Criteria on Clinical Outcomes in Patients with ST-segment Elevation Myocardial Infarction.

AIMS: Bleeding complications are often observed in patients with ST-segment elevation myocardial infarction (STEMI). Although the Japanese version of the high bleeding risk criteria (J-HBR) were established, it has not been sufficiently validated in patients with STEMI. This retrospective study aims to examine whether J-HBR is associated with cardiovascular and bleeding events in patients with STEMI. METHODS: We included 897 patients with STEMI and divided them into the J-HBR group (n=567) and the non-J-HBR group (n=330). The primary endpoint was the major adverse cardiovascular events (MACE), defined as the composite of all-cause death, non-fatal myocardial infarction, ischemic stroke, and systemic embolism. Another primary endpoint was total bleeding events defined as type 3 or 5 bleeding events as defined by the Bleeding Academic Research Consortium . RESULTS: During the median follow-up duration of 573 days, 187 MACE and 141 total bleeding events were observed. The Kaplan-Meier curves showed that MACE and total bleeding events were more frequently observed in the J-HBR group than in the non-J-HBR group (p＜0.001). Multivariate Cox hazard analysis revealed that after controlling for multiple confounding factors, the J-HBR group was significantly associated with MACE (hazard ratio [HR] 4.676, 95% confidence interval (CI) 2.936-7.448, p＜0.001) and total bleeding events (HR 6.325,95% CI 3.376-11.851, p＜0.001). CONCLUSIONS: J-HBR is significantly associated with MACE and total bleeding events in patients with STEMI. This study validated J-HBR as a risk marker for bleeding events and suggests J-HBR as a potential risk marker for MACE in patients with STEMI.

Impact of Excessive Increase in Systolic Blood Pressure after Exercise on Clinical Outcomes in Patients with ST-Segment Elevation Myocardial Infarction.

OBJECTIVE: Although the clinical outcomes for patients with ST-elevation myocardial infarction (STEMI) have improved significantly, some patients still experience poor clinical outcomes. The available risk classifications focus on the short-term outcomes, and it remains important to find high-risk features among patients with STEMI. In Japan, the 200 m walk electrocardiogram (ECG) test is widely performed before discharge. The purpose of this study was to investigate the association between the excessive increase in systolic blood pressure (SBP) following a 200 m walk and the long-term clinical outcomes in patients with STEMI. METHODS: We included 680 patients with STEMI and divided those into an excessive increase in SBP group (n = 144) and a non-excessive increase in SBP group (n = 536) according to the SBP increase after a 200 m walk ECG test. We defined an excessive increase in SBP as SBP ≥ 20 mmHg either just after or 3 min after a 200 m walk ECG test. The primary endpoint consisted of major cardiovascular events (MACE), defined as the composite of all-cause death, non-fatal myocardial infarction, readmission for heart failure, and ischemia-driven target vessel revascularization. RESULTS: The median follow-up duration was 831 days. MACE was more frequently observed in the excessive increase in SBP group (24.3%) than in the non-excessive increase in SBP group (15.1%). Multivariate Cox hazard analysis revealed that the excessive increase in SBP was significantly associated with MACE (HR 1.509, 95% CI: 1.005-2.267, p = 0.047) after controlling for multiple confounding factors. CONCLUSION: An excessive increase in SBP after the 200 m walk ECG test was significantly associated with MACE in patients with STEMI. The 200 m walk ECG test is simple and low-cost, but may help to identify high-risk patients with STEMI.

Appetite Predicts Long-Term Clinical Outcomes in Patients with Acute Myocardial Infarction.

BACKGROUND: Recently, the nutritional status of patients has drawn attention in an aging society. Early studies have reported that nutritional status is related to long-term outcomes in patients with acute myocardial infarction (AMI). However, it is not necessarily simple to evaluate the nutritional status of patients with AMI. We hypothesized that appetite before discharge can be a predictor for long-term adverse cardiovascular events in patients with AMI. This retrospective study aimed to investigate whether appetite is related to long-term adverse outcomes in patients with AMI. METHODS: This study included 1006 patients with AMI, and divided them into the good appetite group (n = 860) and the poor appetite group (n = 146) according to the percentage of the dietary intake on the day before discharge. Major adverse cardiac events (MACE), which were defined as a composite of all-cause death, non-fatal MI, and re-admission for heart failure, were set as the primary outcome. RESULTS: The median follow-up duration was 996 days, and a total of 243 MACE was observed during the study period. MACE was more frequently observed in the poor appetite group than in the good appetite group (42.5% versus 21.0%, p < 0.001). In the multivariate COX hazard model, poor appetite was significantly associated with MACE (Hazard ratio 1.698, 95% confidence interval 1.243-2.319, p < 0.001) after controlling for multiple confounding factors. CONCLUSION: Appetite at the time of discharge was significantly associated with long-term clinical outcomes in patients with AMI. Patients with poor appetite should be carefully followed up after discharge from AMI.

Factors Associated with In-Hospital Death in Patients with Killip Class 3 Acute Myocardial Infarction.

The clinical outcomes in acute myocardial infarction (AMI) patients with Killip class 3 are often inconsistent with those in the literature, and the factors associated with poor outcomes have not been sufficiently investigated. The purpose of this study was to identify factors associated with in-hospital death in AMI patients with Killip class 3. We included 205 AMI patients with Killip class 3, and divided them into a survived group (n = 189) and in-hospital death group (n = 16). The primary objective was to identify factors associated with in-hospital death using multivariate analysis. Age was significantly younger in the survived group than in the in-hospital death group (73.1 ± 11.2 versus 83.2 ± 6.2 years, P < 0.001). Systolic blood pressure (SBP) was significantly higher in the survived group than in the in-hospital death group (150.0 ± 31.2 versus 124.8 ± 25.3 mmHg, P = 0.002). The prevalence of TIMI thrombus grade ≥ 2 was significantly greater in the in-hospital death group than in the survived group (56.3 versus 22.2%, P = 0.005). In multivariate logistic regression analysis, in-hospital death was significantly associated with age [odds ratio (OR) 1.168, 95% confidence interval (CI) 1.061-1.287, P = 0.002] and TIMI thrombus grade ≥ 2 (versus ≤ 1: OR 5.743, 95% CI 1.717-19.214, P = 0.005), and inversely associated with SBP on admission (per 10 mmHg increase: OR 0.764, 95% CI 0.613-0.953, P = 0.017). In conclusion, in-hospital death was associated with age and coronary thrombus burden, and was inversely associated with SBP on admission in patients with Killip class 3. It may be important to recognize these high risk features to improve the clinical outcomes of patients with Killip class 3.

Comparison of long-term outcomes after trans-catheter aortic valve implantation between patients primarily diagnosed by cardiac murmur and those diagnosed by other reasons.

Careful auscultation is the first step to diagnose aortic stenosis (AS). The aim of this study was to compare clinical outcomes following transcatheter aortic valve implantation (TAVI) between the patients primarily diagnosed by heart murmur and those diagnosed by other reasons. We retrospectively included 258 patients who underwent TAVI in our medical center, and divided those into the murmur group (n = 81) and the other-reason group (n = 177) according to the primary reason for AS diagnosis. The primary endpoint was the major adverse cardiovascular and cerebrovascular events (MACCE), which was defined as the composite of cardiovascular death, hospitalization due to acute decompensated heart failure, and disabling stroke. The murmur group included younger patients than the other-reason group (82.8 year-old vs. 84.0 year-old, P = 0.02). History of AF was more frequently observed in the other-reason group than in the murmur group (21.5% vs. 7.4%, P <0.01). STS score and logistic EuroSCORE were lower in the murmur group than in the other-reason group (STS: 4.7% vs. 7.2%, P <0.01, logistic EuroSCORE: 8.3% vs. 11.2%, P <0.01). The median follow-up period was 562 days. MACCE was more frequently observed in the other-reason group than in the murmur group (27.7% vs. 9.9%, Log Rank P <0.01). The multivariate COX hazard analysis revealed that the AS patients primarily diagnosed by heart murmur was inversely associated with MACCE (HR 0.38, 95%CI 0.17-0.86, P = 0.020). Among AS patients who underwent TAVI, the patients primarily diagnosed by heart murmur were significantly associated with favorable long-term clinical outcomes.

S-1 mediates the inhibition of lymph node metastasis in oral cancer cells.

S-1, an oral fluorouracil antitumor drug, is composed of three agents: tegafur (FT), 5-chloro-2,4-dihydroxypyridine (CDHP), and potassium oxonate (Oxo). Approximately 50% of oral squamous cell carcinomas (OSCC) exhibit cervical lymph node metastasis. The extent of lymph node involvement is a major determinant in both staging and prognosis of the majority of OSCC. The purpose of this study was to examine the effect of S-1 on the metastatic potential of OSCC cells. We used orthotopic green fluorescence protein (GFP) SAS-L1, in BALB/c nu/nu mice. Mice received oral doses of either 5% hydroxypropylmethylcellulose (HPMC) for control or S-1 (20 mg/kg) and were autopsied at 2 weeks. We also performed in vitro experiments using concomitant 5-fluorouracil (5-FU) and CDHP as a drug model of S-1 to determine the effect of S-1 on OSCC invasion and metastasis. Although 100% (11 of 11) of mice not treated with S-1 showed cervical lymph node metastasis, only 54.4% (6 of 11) of S-1 treated mice demonstrated metastasis. In in vitro experiments, OSCC cells treated with 5-FU and CDHP showed a marked reduction in invasiveness and in adhesion to laminin coated plates. Western blot analysis revealed that treatment with 5-FU and CDHP suppressed expression of integrins alphav, alpha3, alpha6, beta1, beta3, beta4, beta5, and beta6. These results suggest that S-1 inhibits tumor proliferation and lymph node metastasis in OSCC cells. Moreover, expression of integrin subunits and the integrin signal transduction pathway may be closely related to metastasis suppression.

Telomerase-specific virotheranostics for human head and neck cancer.

PURPOSE: Long-term outcomes of patients with squamous cell carcinoma of the head and neck (SCCHN) remain unsatisfactory despite advances in combination of treatment modalities. SCCHN is characterized by locoregional spread and it is clinically accessible, making it an attractive target for intratumoral biological therapies. EXPERIMENTAL DESIGN: OBP-301 is a type 5 adenovirus that contains the replication cassette in which the human telomerase reverse transcriptase promoter drives expression of the E1 genes. OBP-401 contained the replication cassette and the green fluorescent protein (GFP) gene. The antitumor effects of OBP-301 were evaluated in vitro by the sodium 30-[1-(phenylaminocarbonyl)-3,4-tetrazolium]-bis(4-methoxy-6-nitro)benzene sulfonic acid hydrate assay and in vivo in an orthotopic xenograft model. Virus spread into the lymphatics was also orthotopically assessed by using OBP-401. RESULTS: Intratumoral injection of OBP-301 resulted in the shrinkage of human SCCHN tumors orthotopically implanted into the tongues of BALB/c nu/nu mice and significantly recovered weight loss by enabling oral ingestion. The levels of GFP expression following ex vivo infection of OBP-401 may be of value as a positive predictive marker for the outcome of telomerase-specific virotherapy. Moreover, whole-body fluorescent imaging revealed that intratumorally injected OBP-401 could visualize the metastatic lymph nodes, indicating the ability of the virus to traffic to the regional lymphatic area and to selectively replicate in neoplastic lesions, resulting in GFP expression and cell death in metastatic lymph nodes. CONCLUSIONS: These results illustrate the potential of telomerase-specific oncolytic viruses for a novel therapeutic and diagnostic approach, termed theranostics, for human SCCHN.

Inhibition of cyclooxygenase-2 suppresses the invasiveness of oral squamous cell carcinoma cell lines via down-regulation of matrix metalloproteinase-2 production and activation.

Increased cyclooxygenase (COX-2) expression in tumors is known to be correlated with tumor invasion, angiogenesis, resistance to apoptosis, and suppression of host immunity. We previously reported that the invasiveness of human oral squamous cell carcinoma (OSCC) cell lines NA and HSC-4 was suppressed by treatment with either NS-398, a selective COX-2 inhibitor, or COX-2 antisense oligonucleotide (AS). In the present study, to explore the effects of COX-2 inhibition on the interaction between cancer cells and fibroblasts, we examined the effects of these anti-COX-2 reagents on the expression of matrix metalloproteinases (MMPs) in fibroblast cell lines WI-38 and MRC-5. Western blotting and enzyme-linked immunosorbent assay revealed that NS-398 and COX-2 AS down-regulated the expression and secretion of MMP-2 and the tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) in human fibroblast cell lines. Furthermore, invasion activity of OSCC cells was down-regulated by the addition of culture supernatant from fibroblasts treated with anti-COX-2 reagents in a Matrigel invasion assay. These results suggest that selective COX-2 inhibition suppresses the invasion activity of OSCC cells via down-regulation of an MMP-2-activating mechanism involving TIMP-2 and production of the MMP-2 protein by an interaction between cancer cells and stromal fibroblasts. Genetic or pharmacological inhibition of COX-2 may therefore be a beneficial strategy in the treatment of OSCC.

Antitumor activity of suberoylanilide hydroxamic acid against human oral squamous cell carcinoma cell lines in vitro and in vivo.

It has been reported recently that histone deacetylase inhibitors (HDACIs) can block the growth of a variety of malignant tumor cells by reversing the silencing of the tumor suppressor genes; these will be the anticancer agents of the next generation. In this study, we evaluated the antitumor effects of the HDACI suberoylanilide hydroxamic acid (SAHA) on oral squamous cell carcinoma (OSCC) and investigated its molecular mechanism. SAHA suppressed the in vitro proliferation of OSCC cell lines in a dose- and time-dependent manner. Flow cytometric analyses showed that treatment with SAHA led to G1 phase cell-cycle arrest of OSCC cells, accompanying a decrease in the percentage of S-phase cells. Western blot analyses demonstrated that the expression of p21 protein was remarkably augmented and hyperacetylation of p53 was induced after SAHA treatment. These results suggest that administration of SAHA suppresses OSCC growth through G1 phase arrest. Additionally, we observed that the growth of xenograft SAS tumors in nude mice was significantly blocked by the administration of SAHA without major adverse effects.

Inhibition of TGF-beta1 suppresses motility and invasiveness of oral squamous cell carcinoma cell lines via modulation of integrins and down-regulation of matrix-metalloproteinases.

Transforming growth factor (TGF)-beta1 is a multifunctional polypeptide that regulates a variety of cellular processes. Several studies have indicated that it is associated with epithelial-mesenchymal transition, angiogenesis, migration and metastases in many types of malignant tumors. We have used a wound-healing assay and a Matrigel invasion assay to evaluate the effects of TGF-beta1 and TGF-beta receptor I kinase inhibitor (TRI) on the cell motility and invasiveness of the human oral squamous cell carcinoma (OSCC) cell lines SAS-L1 and HSC-3. While TGF-beta1 enhanced the migration and invasion of OSCC cells, TRI significantly suppressed the migration and invasion of these cells. Exogenous TGF-beta1 up-regulated the activity of type IV collagenase (gelatinase A and gelatinase B), whereas TRI down-regulated the activity of these matrix metalloproteinases. Western blot analysis revealed that TGF-beta1 enhanced the expression of alpha5, alphav, beta1, beta6 and alphavbeta3 integrin subunits, and these enhanced integrins were down-regulated by treatment with TRI. These results suggest that the inhibition of TGF-beta1 suppresses motility and invasiveness of OSCC cells via modulation of integrins and matrix-metalloproteinases. Therefore, targeting the TGF-beta1 signaling pathway could be beneficial in the treatment of patients with OSCC.

Hypoxia induces resistance to 5-fluorouracil in oral cancer cells via G(1) phase cell cycle arrest.

Malignant tumors are exposed to various levels of hypoxic condition in vivo. It has been known that tumor cells under hypoxia are resistant to chemotherapies. To clarify the mechanism of the hypoxia-induced chemoresistance, we evaluated the effects of hypoxia on the resistance of oral squamous cell carcinoma (OSCC) cell lines to 5-fluorouracil (5-FU). OSCC cells were divided to two groups by the proliferation activity under hypoxic condition; hypoxia-resistant (HR) and hypoxia-sensitive (HS) cells. Growth of HS cells were inhibited by hypoxia and introduced to G(1) arrest in cell cycle. 5-FU effect on HS cell viability was markedly reduced in hypoxic condition without an induction of chemoresistant related protein, P-glycoprotein. However, proliferation, cell cycle, and 5-FU sensitivity of HR cells were not affected by hypoxia. Hypoxia-inducible factor (HIF)-1alpha was induced by hypoxia in all OSCC cell lines, but diminished in HS cells within 48h. Expression of p21 and p27 was strongly augmented and CyclinD expression was reduced by hypoxia in HS cells. However, the expression of these proteins was constitutive in HR cells during 48h hypoxic culture. Phosphorylation of mammalian target of rapamycin (mTOR) was reduced by hypoxia in HS cells. From these findings, we concluded that HS OSCC cells acquire 5-FU resistance under hypoxia by G(1)/S transition through an upregulation of cell cycle inhibitors.

Enhanced susceptibility to apoptosis of oral squamous cell carcinoma cells subjected to combined treatment with anticancer drugs and phosphatidylinositol 3-kinase inhibitors.

The purpose of this study was to determine whether phosphatidylinositol 3-kinase (PI 3-K) inhibitors could modulate the apoptotic activity of the anticancer drugs cisplatin, 5-fluorouracil or docetaxel in an oral squamous cell carcinoma (OSCC) cell line, HSC-2. In preliminary experiments, cisplatin, 5-fluorouracil and docetaxel inhibited the proliferation of OSCC cells in a dose-dependent manner. We found that two PI 3-K inhibitors, wortmannin and LY294002, markedly suppressed the phosphorylation of Akt in OSCC cells. Treatment of OSCC cells with PI 3-K inhibitors significantly enhanced cisplatin-, 5-fluorouracil- or docetaxel-induced apoptosis. Caspase-3 and -9 inhibitors, but not a caspase-8 inhibitor, reduced anticancer drug-mediated apoptosis in PI 3-K inhibitor-treated OSCC cells, suggesting that the apoptotic pathway induced by the combination of anticancer drug therapy and PI 3-K inhibition may be functionally related to the intrinsic apoptotic pathway in OSCC cells. Expression of Bcl-2, cellular inhibitor of apoptosis protein-1 (cIAP-1), and X-linked IAP was down-regulated, and expression of Bax was up-regulated by PI 3-K inhibitors, while that of Bcl-xL, Bak and cIAP-2 was not attenuated. We also found that Bad phosphorylation was down-regulated by PI 3-K inhibitors. These results suggested that inhibition of PI 3-K enhances the susceptibility of OSCC cells to anticancer drug-mediated apoptosis through regulation of expression and post-translational modification of both pro- and anti-apoptotic proteins. These findings could potentially lead to new strategies for improving the efficacy of anticancer drugs in OSCC cells.