Hydrogen gas activates coenzyme Q10 to restore exhausted CD8+ T cells, especially PD-1+Tim3+terminal CD8+ T cells, leading to better nivolumab outcomes in patients with lung cancer

As previously reported, hydrogen gas improves the prognosis of patients with cancer by restoring exhausted CD8⁺ T cells into active CD8⁺ T cells, possibly by activating mitochondria. As mitochondrial activators exhibit synergistic effects with nivolumab, the current study investigated whether hydrogen gas also affects the clinical outcomes of nivolumab. A total of 42 of 56 patients with lung cancer treated with nivolumab received hydrogen gas. Exhausted markers (PD-1 and Tim-3) on cell populations in the CD8⁺ T cell differentiation pathway were analyzed using flow cytometry. The concentration of coenzyme Q10 (CoQ10) was measured as a marker of mitochondrial function. The 42 patients treated with hydrogen gas and nivolumab (HGN) indicated a significantly longer overall survival (OS) compared with those treated with nivolumab only (n=14). In multivariate analysis, PD-1⁺Tim-3⁺terminal CD8⁺ T cells (PDT+) were an independent poor prognostic factor in OS, and CoQ10 showed a tendency to be associated with improved OS. The change in the rate of PDT+ and CoQ10 after vs. before HGN (PDT+ ratio and CoQ10 ratio, respectively) revealed that patients with low PDT+ ratio (<0.81) and high CoQ10 ratio (>1.175) had significantly longer OS compared with those with high PDT+ ratio and low CoQ10 ratio. Furthermore, PDT+, with a significant reverse correlation with CoQ10, was significantly lower in patients with high CoQ10 and/or CoQ10 ratio than in those low CoQ10 and/or CoQ10. Hydrogen gas has been suggested to enhance the clinical efficacy of nivolumab by increasing CoQ10 (mitochondria) to reduce PDT+, with PDT+ and CoQ10 as reliable negative and positive biomarkers of nivolumab, respectively.

Hydrogen gas restores exhausted CD8+ T cells in patients with advanced colorectal cancer to improve prognosis

Exhausted cluster of differentiation (CD)8+ T cells lose immunological activity due to mitochondrial dysfunction caused by peroxisome proliferator‑activated receptor γ coactivator 1α (PGC‑1α) inactivation, resulting in a poor prognosis in patients with cancer. As hydrogen gas was recently reported to activate PGC‑1α, the present study investigated whether it restores exhausted CD8+ T cells to improve prognosis in patients with stage IV colorectal cancer. A total of 55 patients with histologically and clinically diagnosed stage IV colorectal carcinoma were enrolled between July 2014 and July 2017. The patients inhaled hydrogen gas for 3 h/day at their own homes and received chemotherapy at the Tamana Regional Health Medical Center (Tamana, Kumamoto, Japan). The CD8+ T cells were isolated from the peripheral blood and their phenotype was analyzed by flow cytometry. It was found that exhausted terminal programmed cell death 1 (PD‑1)+ CD8+ T cells in the peripheral blood are independently associated with worse progression‑free survival (PFS) and overall survival (OS). Notably, hydrogen gas decreased the abundance of exhausted terminal PD‑1+ CD8+ T cells, increased that of active terminal PD‑1‑ CD8+ T cells, and improved PFS and OS times, suggesting that the balance between terminal PD1+ and PD1‑ CD8+ T cells is critical for cancer prognosis. Therefore, a novel system for patient classification (category 1‑4) was developed in the present study based on these two indices to assist in predicting the prognosis and therapeutic response. Collectively, the present results suggested that hydrogen gas reverses imbalances toward PD‑1+ CD8+ T cells to provide an improved prognosis.

[Immunological Effect of Hydrogen Gas-Hydrogen Gas Improves Clinical Outcomes of Cancer Patients]

It has been reported that PD-1-expressing CD8+ T cells in the peripheral blood of cancer patients are associated with poor cancer prognosis. In addition, these cells are in a state of energy shortage caused by mitochondrial dysfunction with a low level of PGC-1a. Recently, hydrogen gas was reported to activate PGC-1a, leading to the enhancement of mitochondrial activity. In the present study, we investigated whether hydrogen gas influences the proportion of PD-1+ CD8+ T cells in the peripheral blood of 55 Stage IV colorectal carcinoma patients. We found that the proportion of terminal PD-1+ CD8+ T cells was an independent factor for poor prognosis. We also found that the proportion of terminal PD-1+ CD8+ T cells was reduced in 35 out of 55 patients(63.6%)and was increased in 39 out of 55 patients(70.9%)after treatment with hydrogen gas. The ratio of the terminal PD-1+ CD8+ T cells after hydrogen gas treatment to that before hydrogen gas treatment(terminal PD-1+ CD8+ T cell ratio)was found to be an independent factor predicting PFS and OS. Out of another 26 patients treated with nivolumab, 14 patients treated with a combined therapy of hydrogen gas and nivolumab showed a significantly longer OS than the remaining 12 patients who were treated with nivolumab alone. These results suggest that hydrogen gas improves the prognosis of cancer patients by reducing the proportion of terminal PD-1+ CD8+ T cells.

CD57 ratio as a convenient and useful immunological and prognostic parameter for stage IV carcinoma

Cluster of differentiation (CD)8+CD57+ T cells are derived through the CD8+ T cell-differentiation signaling pathway from early differentiated CD27+CD8+CD57-T cells (early-CD8+ T cells) to terminal-differentiated CD27-CD8+CD57+ T cells (terminal-CD8+ T cells) via intermediate-differentiated CD27+CD8+CD57+ T cells (intermediate-CD8+ T cells). The increase of CD8+CD57+ T cells in the peripheral blood of patients with cancer has been associated with prognosis, which suggests their suitability as a candidate immunological marker. The present study investigated the association of these CD57-related CD8+ T cell populations in the peripheral blood of 100 Stage IV cancer patients with progression-free survival (PFS), using a Cox regression model. Univariate analysis indicated that early- and intermediate-CD8+ T cells were associated with shorter PFS, whereas terminal-CD8+ T cells were associated with longer PFS. A strong inverse correlation was observed between early- and terminal-CD8+ T cells, and multivariate analysis demonstrated that the CD57 ratio (terminal-CD8+ T cells/early-CD8+ T cells) was a more significant independent prognostic factor compared with early- or terminal-CD8+ T cells. Patients with a higher CD57 ratio had a significantly longer PFS compared with those with a lower CD57 ratio, in whom terminal-CD8+ T cells were supposed to be predominant. Conversely, results indicated inhibition of the CD8+ T cell differentiation signaling pathway in patients with a low CD57 ratio, which lead to a predominance of early-CD8+ T cells, a characteristic of immunosuppressive cells. The present findings suggested that the CD57 ratio appears to be a powerful immunological prognostic parameter obtained from the peripheral blood, precisely reflecting the state of CD8+ T cell-differentiation.

Terminally differentiated CD8+ T cells and CD57-FOXP3+CD8+ T cells are highly associated with the efficacy of immunotherapy using activated autologous lymphocytes

Treatment with activated autologous lymphocytes (AALs) has demonstrated mixed results for cancer treatment. Preliminary results revealed that the proportion of cluster of differentiation (CD)8⁺CD57⁺ T cells is significantly increased in AALs, indicating that they are able to determine treatment outcome. Therefore, the role of CD8⁺CD57⁺ T cells in AAL efficacy was investigated. T lymphocytes were isolated from 35 patients with stage IV gastric carcinomas (17 men and 18 women; aged 41-84 years) receiving immunotherapy using AALs (IAAL). Using fluorescence activated cell sorting, CD8, CD27, CD57, and forkhead box protein 3 (FOXP3) expression was investigated on CD8⁺ T cell populations in CD8⁺ T cell differentiation prior to and following in vitro culture. The association between these populations and progression-free survival (PFS) was analyzed using Cox univariate, and multivariate analyses and Kaplan-Meier survival analysis. CD57 expression was negative in early-differentiated CD8⁺ T cells (CD27⁺CD8⁺CD57^-), and positive in intermediate- (CD27⁺CD8⁺CD57⁺) and terminal- (CD27^-CD8⁺CD57⁺) differentiated CD8⁺ T cells. Univariate analysis revealed a significant association between terminal-CD8⁺ T cells and longer PFS times (P=0.035), whereas CD57^-FOXP3⁺CD8⁺ T cells were associated with shorter PFS times. Multivariate analysis revealed that CD57^-FOXP3⁺CD8⁺ T cells was an independent poor prognostic factor, whereas CD57⁺FOXP3⁺CD8⁺ T cells were not associated with PFS. Although IAAL increased the proportion of terminal-CD8⁺ T cells relative to the pre-culture proportions, patients with a high CD57^-FOXP3⁺CD8⁺ T cell percentage exhibited repressed terminal-CD8⁺ T cell induction, leading to poor patient prognosis. Terminally differentiated CD27^-CD8⁺CD57⁺ T cells were responsible for the effectiveness of AALs; however, CD57^-FOXP3⁺CD8⁺ T cells abrogated their efficacy, possibly by inhibiting their induction.

Nutritional variables predict chances of returning home and activities of daily living in post-acute geriatric care

Background

Little is known about the association between malnutrition and the chances of returning home from post-acute facilities in older adult patients. This study aimed to understand whether malnutrition and malnutrition-related factors would be determinants for returning home and activities of daily living (ADL) at discharge after post-acute care.

Methods

Patients aged ≥65 years living at home before the onset of an acute disease and admitted to a post-acute ward were enrolled (n=207) in this prospective observational study. Malnutrition was defined based on the criteria of the European Society for Clinical Nutrition and Metabolism. Nutritional parameters included the nutritional intake at the time of admission and oral conditions evaluated by the Oral Health Assessment Tool (OHAT). The Barthel Index was used to assess daily activities. A Cox regression analysis of the length of stay was performed. Multivariable linear regression analyses to determine associations between malnutrition, returning home, and ADL at discharge were performed, after adjusting the variables of acute care setting.

Results

The mean patient age was 84.7±6.7 years; 38% were men. European Society for Clinical Nutrition and Metabolism-defined malnutrition was observed in 129 (62.3%) patients, and 118 (57.0%) of all patients returned home. Multivariable regression analyses showed that malnutrition was a negative predictor of returning home (hazard ratio: 0.517 [0.351–0.761], p=0.001), and an increase in the nutritional intake (kcal/kg/d) was a positive predictor of the Barthel Index at discharge (coefficient: 0.34±0.15, p=0.021). The OHAT was not associated with returning home and ADL.

Conclusion

Malnutrition and nutritional intake are associated with returning home and ADL at discharge, respectively, after post-acute care. Further studies investigating the effects of a nutritional intervention for post-acute patients would be necessary.

Interferential current sensory stimulation, through the neck skin, improves airway defense and oral nutrition intake in patients with dysphagia: a double-blind randomized controlled trial

Background

Neuromuscular electrical stimulation with muscle contraction, administered through the skin of the neck, improves a patient’s swallowing ability. However, the beneficial effects of transcutaneous electrical sensory stimulation (TESS), without muscle contraction, are controversial. We investigated the effect of TESS, using interferential current, in patients undergoing dysphagia rehabilitation.

Methods

This double-blind, randomized controlled trial involved 43 patients who were prescribed in-hospital dysphagia rehabilitation for ≥3 weeks. Patients were randomly assigned to the sensory stimulation (SS) or sham groups; all received usual rehabilitative care plus 2 weeks of SS or sham intervention. Outcome measures included cough latency times against a 1% citric acid mist, functional oral intake scale (FOIS) scores, and oral nutritional intake – each determined after the second and third week following treatment initiation.

Results

Mean patient age was 84.3±7.5 years; 58% were women. The SS and sham groups had similar baseline characteristics. Changes in cough latency time at 2 weeks (−14.1±14.0 vs −5.2±14.2 s, p=0.047) and oral nutrition intake at 3 weeks (437±575 vs 138±315 kcal/day, p=0.042) improved more in the SS group than in the sham group. Changes in cough frequency and FOIS scores indicated better outcomes in the SS group, based on substantial effect sizes.

Conclusion

TESS, using interferential current through the neck, improved airway defense and nutrition in patients suffering from dysphagia. Further large-scale studies are needed to confirm the technique’s effect on swallowing ability.

Decreased Skeletal Muscle Mass and Risk Factors of Sarcopenic Dysphagia: A Prospective Observational Cohort Study

Background

Dysphagia is a known risk factor for malnutrition and pneumonia. Although sarcopenia is hypothesized to cause dysphagia, its causality remains unclear. Thus, this study aimed to investigate causality and the risk factors for sarcopenic dysphagia.

Methods

We enrolled 95 hospitalized patients aged 65 years or older who had restricted oral intake without dysphagia. The skeletal muscle index and Functional Oral Intake Scale were used to evaluate muscle mass and swallowing ability, respectively. Nutritional status, assessed by body mass index, the Mini Nutritional Assessment-Short Form, and energy intake; activity of daily living, assessed by the Barthel Index; hand-grip strength; duration of oral intake restriction; and cognitive status were measured. Dysphagia (Functional Oral Intake Scale ≤ 5) was determined after 2 months.

Results

The participants' mean age was 83.2 ± 8.0 years; 63% were women. Of the surviving 82 patients, 63 (77%) had sarcopenia and 21 (26%) developed dysphagia, all of whom had sarcopenia (p = .002). Most variables were risk factors for dysphagia on univariate analysis. Decreased skeletal muscle index (odds ratio [OR] 24.0, 95% confidence interval [CI] 3.6-159.0, p = .001), Barthel Index (OR 12.9, 95% CI 2.1-78.4, p = .005), and body mass index (OR 11.4, 95% CI 1.8-70.5, p = .009) were independent predictors of dysphagia in the multivariate analysis.

Conclusion

This study provides evidence for sarcopenic dysphagia and its risk factors. Preventive and therapeutic interventions require further study.

Predictive Accuracy of Calf Circumference Measurements to Detect Decreased Skeletal Muscle Mass and European Society for Clinical Nutrition and Metabolism-Defined Malnutrition in Hospitalized Older Patients

Background/Aims: The ability to readily diagnose sarcopenia and malnutrition in a clinical setting is essential. This study is aimed at clarifying the calf circumference (CC) cut-off values for decreased skeletal muscle mass (SMM), according to the Asian Work Group for Sarcopenia's criteria definition of sarcopenia, and those for European Society for Clinical Nutrition and Metabolism-defined malnutrition, in hospitalized Japanese patients. Methods: The study involved 1,164 patients aged ≥65 years. Predictive CC cut-off values were determined using receiver operating curve (ROC) analyses. The predictive validity of the cut-off values was confirmed against in-hospital mortality. Results: There were 654 females and 510 males (mean age, 83.5 ± 8.2 years). Decreased SMM and malnutrition were observed in 80.4 and 32.8% of all patients, respectively. ROC analyses identified CCs of ≤29 cm (female, area under the curve [AUC] 0.791) and ≤30 cm (male, AUC 0.832) as cut-off values for decreased SMM, and CCs of ≤26 cm (female, AUC 0.798) and ≤28 cm (male, AUC 0.837) for malnutrition. CC cut-off values for SMM and malnutrition were independently correlated with in-hospital mortality. Conclusions: The study determined appropriate cut-off values for CC to identify decreased SMM and malnutrition according to the relevant guidelines.

Effects of hydrogen gas on exhausted CD8+ T cells (PD-1-positive, terminally differentiated CD8+ T cells)

e23071

Background: CD8+ T cells progress from an early-differentiated (early-CD8+ T cells) to a terminally differentiated state (terminal-CD8+ T cells). PD-1 expression is rapidly upregulated in antigen-activated T cells, and rapidly downregulated when the antigen is cleared. In the presence of persistent antigen stimulation, such as that in cancer patients, PD-1 expression is not downregulated and terminal-CD8+T cells become exhausted. Methods: Using flow cytometry, we investigated PD-1 expression in CD8+T cells in the peripheral blood of 37 patients with stage IV cancer, before and after they received hydrogen gas treatment. We analyzed associations between treatment and progression-free survival (PFS) using Cox and Kaplan-Meier survival analyses. Results: Treatment lead to partial response (PR) in 12 patients and stable disease (SD) in 14 patients, with response rates of 32.4% and 37.8%, respectively (with an overall clinical response rate of 70.3%), and reduced the number of PD-1-positive, terminal-CD8+ T cells in 9 of 12 patients with PR (75%) and in 8 of 14 patients with SD (57%). However, in 8 of 11 patients with progressive disease (PD) (72.7%), these cell counts increased. Multivariate analyses demonstrated that higher PD-1-positive, terminal-CD8+ T cell counts were associated with shorter PFS periods, both before (hazard ratio [HR] = 3.23; 95% confidence interval [CI], 1.475–7.070; p = 0.003) and after (HR = 2.75; 95% CI, 1.273–5.951; p = 0.01) treatment, although the hazard ratio was decreased by treatment. Additional analysis showed that patients with higher PD-1-positive, terminal-CD8+ T cell counts had shorter survival rates than those with lower counts, both before and after treatment (log rank test, p = 0.001 and p = 0.005, respectively). The 20-month survival rates for patients with higher PD-1-positive, terminal-CD8+T cell counts improved from 0% to 36.7% after treatment. Conclusions: These results suggest that PD-1-positive, terminal-CD8+ T cell counts are highly associated with PFS duration in patients with stage IV carcinomas, and hydrogen gas treatment contributes to clinical outcomes by reducing PD-1-positive, terminal-CD8+ T cell counts.

Muscle Mass Loss Is a Potential Predictor of 90-Day Mortality in Older Adults with Aspiration Pneumonia

OBJECTIVES

To investigate the association between loss of muscle mass and aspiration pneumonia (AP).

DESIGN

Prospective observational cohort.

SETTING

Acute geriatric hospital.

PARTICIPANTS

Individuals admitted to the hospital for AP (N = 151; mean age 85.9; 49.7% male).

MEASUREMENTS

Appendicular skeletal muscle index (ASMI; appendicular skeletal muscle mass divided by height squared) was used to evaluate muscle mass. Data on age, sex, body mass index, Mini Nutritional Assessment-Short Form score, Barthel Index score, Charlson Comorbidity Index score, and pneumonia severity (Japanese version of the CURB-65 (C (confusion), U (blood urea nitrogen ≥20 mg/dL), R (respiratory rate ≥30 breaths/min), B (systolic blood pressure <90 mmHg or diastolic blood pressure ≤60 mmHg), 65 (aged ≥65) severity score (A-DROP)) were obtained. Outcomes included 30- and 90-day mortality.

RESULTS

Mild, moderate, severe, and extremely severe AP were observed in 1.3%, 70.2%, 25.8%, and 2.6% of participants, respectively. On Kaplan-Meier analysis, participants in the lowest ASMI quartile for each sex were more likely to die than those in the other quartiles (log-lank test P = .005). Multivariate logistic analyses showed that ASMI and A-DROP were independent predictors of 90-day mortality; only A-DROP was a significant predictor of 30-day mortality (P < .001). Cox regression analysis also showed that the first ASMI quartile was independently associated with mortality (hazard ratio = 2.19; 95% confidence interval = 1.06-4.52; P = .03).

CONCLUSION

Low muscle mass is a potential predictor of long-term mortality in individuals with AP. Prospectively preventing muscle mass deterioration may be beneficial for recovery from AP in older adults.

Cognitive impairment is independently associated with definitive and possible sarcopenia in hospitalized older adults: The prevalence and impact of comorbidities

AIM

Older adults often present with several comorbidities, including sarcopenia. However, the prevalence of sarcopenia and its associations with other comorbidities in hospitalized older adults are unknown. The present study aimed to determine the prevalence of sarcopenia, and its associations with other comorbidities in hospitalized older adults.

METHODS

The present cross-sectional study included 619 patients admitted to a geriatric hospital. The prevalence of comorbidities in the presence and absence of sarcopenia, nutritional status (according to body mass index and the Mini-Nutritional Assessment-Short Form), and activities of daily living (according to the Barthel Index) were assessed. Sarcopenia was defined as skeletal muscle loss evaluated by both bioelectrical impedance and handgrip strength analyses.

RESULTS

Of the 619 participants (mean age 83.0 ± 8.2 years), 417 (67.4%) and 87 (14.1%) had definitive and possible sarcopenia, respectively. The prevalence rates of cognitive impairment and stroke were significantly higher in patients with definitive sarcopenia and those with possible sarcopenia than in those without sarcopenia (cognitive impairment 54.4%, 70.1% and 20.9%, respectively, P < 0.001; stroke 31.2%, 48.3% and 19.1%, respectively, P < 0.001). Multivariate logistic regression analysis showed that cognitive impairment was independently associated with sarcopenia after adjusting for age, sex, the Mini-Nutritional Assessment-Short Form score, Barthel Index and primary disease (adjusted odds ratio 1.98, 95% confidence interval 1.06-3.71; P = 0.032).

CONCLUSIONS

Sarcopenia might be highly prevalent among hospitalized older adults. Furthermore, cognitive impairment might be an independent explanatory variable of sarcopenia. Therefore, further studies on sarcopenia in patients with cognitive impairment are warranted. Geriatr Gerontol Int 2017; 17: 1048-1056.

PSK may suppress CD57(+) T cells to improve survival of advanced gastric cancer patients

BACKGROUND

A recent report showed that oral adjuvant immunochemotherapy with protein-bound polysaccharide K (PSK) and tegafur/uracil (UFT) for stage II and III colorectal cancer improves overall survival compared with UFT alone. PSK has been supposed to improve survival through immunological mechanisms such as induction of cytokines, regulation of Th1/Th2 balance, and inhibition of immunosuppressive molecules.

METHODS

We investigated the mechanisms by which PSK influences immunological parameters such as Th1 cells (IFN-gamma-positive CD4(+) T cells), Th2 cells (IL-4-positive CD4(+) T cells), Th1/Th2 ratio, NKT cells (CD56(+) T cells and CD57(+) T cells), NK cells, and CD25(+)CD4(+) T cells in stage III gastric cancer patients. Patients were randomly assigned to receive either 3 g PSK plus 300 mg UFT (PSK group) or 300 mg UFT alone (control) orally each day for at least 1 year following their operation.

RESULTS

Twenty-one registered patients with stage III gastric cancer were analyzed. The 3-year overall survival was 62.2% in the PSK group (n = 10) and 12.5% in the control group (n = 11) (P = 0.038). Before operation, there were no significant differences in the proportions of Th1 cells, Th2 cells, Th1/Th2 ratio, CD56(+) T cells, CD57(+) T cells, NK cells, and CD4(+)CD25(+) T cells between PSK and control groups. However, after operation, CD57(+) T cells decreased significantly in the PSK group compared to the control (P = 0.0486). When all patients were analyzed, patients with increased proportion (>18%) of CD57(+) T cells showed worse survival than those with lower (< or = 18%) CD57(+) T cells (3-year survival, 25.0 and 45.7%, respectively; P = 0.046), consistent with our previous report that high CD57(+) is an indicator of poor prognosis in patients with advanced gastric cancer. However, in the group treated with PSK + UFT, 3-year survival of CD57-high patients was as great as that of CD57-low patients (66.7 and 51.4%, respectively; P = 0.67).

CONCLUSION

The present findings suggest that PSK improves overall survival of stage III gastric cancer patients partly by inhibiting CD57(+) T cells, a proven poor prognostic factor in advanced gastric cancer.

Prognostic value of CD57(+) T lymphocytes in the peripheral blood of patients with advanced gastric cancer

BACKGROUND

Natural killer (NK)-like T cells comprising CD56(+) T cells and CD57(+) T cells belong to a subset of CD1d-independent NKT cells playing an important role in regulating immune responses. Although NK-like T cells are reported to increase in patients with advanced gastric carcinomas, it remains unknown how NK-like T cells are involved in disease progression in gastric cancer patients.

METHODS

The proportions of Th1 cells (interferon [IFN]-gamma-producing CD4(+) T cells), Th2 cells (IL-4-producing CD4(+) T cells), and NK-like T cells (CD56(+) T cells and CD57(+) T cells) in the peripheral blood of 48 gastric cancer patients and 20 healthy controls were measured by two-color flow cytometry analysis and by intracellular cytokine analysis to investigate an association of these immune cells with the survival rate of gastric cancer patients.

RESULTS

Univariate analysis showed that Th1 cells and CD57(+) T cells, as well as some clinicopathological factors, significantly influenced the survival rate. CD57-high (> or ==18%) patients survived for a significantly shorter period after surgery compared to CD57-low patients (P = 0.046; Kaplan-Meier, log-rank test) in the stage III-IV patients, but not in the stage I-II patients. Further, multivariate analysis showed that lymphatic invasion was a statistically significant independent risk factor in all the gastric cancer patients, but the proportion of CD57(+) T cells as well as depth of tumor were statistically significant independent risk factors in patients with advanced carcinomas (stage III-IV).

CONCLUSION

An increased proportion (> or ==18%) of CD57(+) T cells in the peripheral blood of patients with advanced gastric carcinomas could indicate a poor prognosis.

[Long-term survival case of advanced gastric cancer with paraaortic lymph node metastasis and peritoneal metastasis from S-1/CDDP combination therapy after reductive operation]

A 72-year-old female patient with type 5 gastric cancer in the upper gastric region underwent surgery. Due to paraaortic lymph node metastasis (#16a1, #16a2) and peritoneal metastasis, total gastrectomy and D0 lymph node dissection were performed. Surgical and pathological findings were poorly differentiated adenocarcinoma, INFbeta, pT3(SE), PM (-), DM (-), ly0, v2, sN3 (#7, #9, #16a1-a2), M0, stage IV. The patient was administered S-1 for 2 weeks at 80 mg/day, received 24-hour continuous intravenous infusion of 80 mg/day on day 8, and then discontinued chemotherapy for 2 weeks, which was regarded as one course. After one course, CT scan showed that the paraaortic lymph node metastasis had almost entirely disappeared. However, due to grade 3 neutropenia, and grade 2 nausea and anorexia in the first course, the treatment was changed to oral administration of UFT (400 mg/day) , which was discontinued one month later due to anorexia. The patient has been in good health without a recurrence for 4 years after surgery. This case suggests that reduction surgery combined with a S-1 regimen is an effective treatment for long-term survival.

Clinical significance of MHC class II-associated invariant chain expression in human gastric carcinoma

MHC class II antigens serve as restricted elements for cell presenting antigens to CD4+ helper T cells. CD4+ T cells and CD8+ cytotoxic T cells, which are tumor-infiltrating lymphocytes (TILs), and play a major role in the survey and attack against tumor cells in primary lesions. Invariant chain (Ii) has several functions in MHC class II-restricted antigen presentation. In addition, Ii is found to be closely involved in the regulation of anti-tumor immunity in several tumor types. However, the significance of Ii expression in tumor cells is not fully illustrated. Immunohistochemical staining of Ii expression was performed in 58 cases of human gastric carcinoma specimens. The prognostic analysis of patients with gastric carcinoma was also performed. A total of 67.2% (39/58) gastric carcinomas were found to be Ii-positive, whereas only 20.7% (12/58) showed positive immunoreactivity with anti-MHC class II determinants. Furthermore, Ii expression showed significant correlation with the differentiation of gastric carcinoma (p<0.05). Ii expression also showed an inverse correlation with the frequency of TILs around carcinoma tissues, as well as with the prognosis of gastric carcinoma (p<0.01). Ii expression is closely correlated with anti-tumor immunity in human gastric carcinoma. Therefore, Ii may serve as an independent clinical marker for poor biological behavior and prognostic analysis in patients with gastric carcinoma.

Identification of genes related to invasion and metastasis in pancreatic cancer by cDNA representational difference analysis

The difference in gene expression between the highly invasive and metastatic cell line PC-1.0 and the weakly invasive and metastatic cell line PC-1 both derived from a pancreatic ductal carcinoma induced by N-nitrosobis (2-oxopropyl) amine (BOP) in Syrian golden hamster was examined using the Representational Difference Analysis (RDA) method. Within 8 clones (cDNA fragments) successfully isolated after subtraction hybridization of PC-1 cDNA from PC-1.0, 5 clones were shown to be specific or highly expressed in PC-1.0 as confirmed by RT-PCR. Among these 5 clones, two known genes, MAP kinase kinase 2 (MKK2) and phosphatidylinositol 4-kinase (PI4K230) were detected by gene sequencing. The specific expressions of MKK2 and PI4K230 in the highly invasive and metastatic cell line PC-1.0 were confirmed by RT-PCR and Northern blotting. By adding the CM of PC1.0 which included the cancer cell dissociation factor (DF), PC-1 cells began to dissociate and migrate from the colonies, and in addition the expression of MKK2 was found to be induced. On the other hand, the expression of PI4K230 was not induced in PC-1 cells by adding the CM of PC-1.0. Interestingly, in PC-1.0 the expression of PI4K230 was completely abolished and apoptosis induced by the PI3K inhibitor wortmannin. These results suggest that both MKK2 and PI4K230 are factors of a signal transduction pathway that might play an important role related to invasion and metastasis through the induction of cell motility and/or the inhibition of apoptosis.

CD3+CD56+CD8+ cells demonstrating a suppressor T cell-like function in the peripheral blood of colon cancer patients

We previously reported that HLA-unrestricted CTLs against MUC-1 were induced from colon cancer patients by stimulating peripheral blood lymphocytes (PBLs) with recombinant MUC-1 vaccinia virus (rVMUC-1). We have performed adoptive immunotherapy (AI) for two gastric and two colon cancer patients, using the rVMUC-1-stimulated T lymphocytes. A significant level of HLA-unrestricted cytotoxicity against MUC-1 was induced in the two colon cancer patients (pA and pB) during the first adoptive immunotherapy, but extremely reduced during the second AI. During the second stimulation phase, the rate of CD3+CD56+CD8+ cells were significantly increased and that of CD3+CD56-CD4+ cells were significantly decreased in the two colon cancer patients as compared to the first AI. CD3+CD56+CD8+ and CD3+CD56-CD4+ cells were isolated from the second AI of the colon cancer patient (pB) and designated as D856 and D4, respectively. The D4 cells demonstrated a high level of HLA-unrestricted CTL activity against MUC-1, but D856 cells did not. When D856 cells were mixed with D4 cells at a D856/D4 ratio of 1:3, 1:2, and 1:1 and used as effector cells, the HLA-unrestricted and MUC-1-specific CTL activity of D4 cells was suppressed in a D856/D4 ratio-dependent manner. Further, D856 cells were highly lytic for the D4 cells demonstrating HLA-unrestricted cytotoxicity against MUC-1. It is concluded that the reduction in HLA-unrestricted cytotoxicity against MUC-1 during the second AI is attributed to the D856 cells killing MUC-1-specific CTLs (D4). Thus, the CD3+CD56+ CD8+ cells seem likely to behave as a suppressor T cell.

CA19-9 epitope a possible marker for MUC-1/Y protein

It has been reported that MUC-1 molecules devoid of the tandem repeat region (MUC-1/Y) are detected preferentially in carcinoma cells and are associated with their progression. However, its clinical significance is still unknown. We constructed a mouse colon adenocarcinoma cell line (MC-38) transduced with either MUC-1/Y cDNA defecting the tandem repeat region (Y-MC-38) or MUC-1/R cDNA containing ten tandem repeats (R-MC-38). RT-PCR of mRNAs derived from Y-MC-38 cells using the specific primers to MUC-1/Y mRNAs, proved the existence of 600 bp RT-PCR products generated only from MUC-1/Y mRNAs. DF3 and CA19-9 epitopes out of the MUC-1-related tumor-associated antigens, have been reported to be involved in the prognosis of cancer patients. We examined the expression of DF3 and CA19-9 epitopes on Y-MC-38 and R-MC-38 cells. Fluorescence-activated cell sorting (FACS) analysis of R-MC-38 and Y-MC-38 cells using two monoclonal antibodies against DF3 (mAb DF3) and CA19-9 (mAb CA19-9) epitopes revealed that R-MC-38 cells expressed DF3 but not CA19-9 [DF3(+)CA19-9(-)], while Y-MC-38 cells expressed CA19-9 but not DF3 [DF3(-)CA19-9(+)]. On Western blot, a 40 kDa protein product was recognized by mAb CA19-9 but not by mAb DF3 on cell lysates of Y-MC-38 cells, whereas a 70 kDa protein product was recognized by mAb DF3 but not by mAb CA19-9 on the cell lysates of R-MC-38. Further, we analyzed the expression of MUC-1/Y mRNAs by RT-PCR on various human cancer cell lines: the gastric cancer cell line AZ521, the pancreatic cancer cell lines PANC-1 and Capan-1, the gall bladder cell line GBK-1, the breast cancer cell line MCF-7, and the colon cancer cell lines HT-29 and Colo205. HT-29 and Capan-1 cells producing the 600 bp RT-PCR product, were positive for mAb CA19-9. These results demonstrate that CA19-9 epitope is produced only on MUC-1/Y core protein, suggesting that CA19-9 epitope may be a specific marker for MUC-1/Y protein.

Presence of RON receptor tyrosine kinase and its splicing variant in malignant and non-malignant human colonic mucosa

The presence of RON and its variant isoform in malignant and non-malignant human colonic tissues was examined by immunohistochemistry using paraffin-embedded sections and RT-PCR analysis followed by direct sequencing of PCR product using RNAs isolated from frozen tissues. In normal colonic mucosa, RON was uniformly expressed in crypt cells, especially in the bottom of crypta. On the other hand, the expression was distributed heterogeneously in adenomas and in colon cancer. The expression of RON was significantly related to the degree of differentiation of colon cancer and the deletion of the expression was observed in colon cancer specimens with high incidence. The RT-PCR analysis of RNA isolated from non-malignant and malignant colonic tissue revealed the presence of two RON mRNA isoforms with 432-bp and 286-bp. Direct sequencing of major product of 432-bp was revealed to be identical to that of human wild-type RON. On the other hand, major product of 286-bp was revealed to be almost identical to that of a splicing variant of RON transcript which has been found in human gastric cancer cell line, KATO-III. The results obtained in this study may indicate that both wild-type RON and its variant isoform play an important role in regulating the normal function of colonic mucosa such as differentiation and motile activity and the expression of both wild-type RON and its variant isoform could be considered to be reduced during malignancy of human colonic mucosa.

Prognostic values of MUC-1 molecule expressing cytokine receptor-like epitope and DF3 in patients with gastric carcinoma

As recently reported, DF3/MUC-1 molecules having cytokine receptor-like sequences (CRL) at the extracellular region, are likely to function in signal transduction pathways. To elucidate the functional significance of CRL expressed on the DF3/MUC1 molecule, immunohistochemical localization of CRL and/or DF3 was investigated in cases of 115 patients with gastric carcinomas, treated by surgical resection. CRL was detected in 65 of 115 patients (56.5%), DF3 in 85 (73.9%), and both DF3 and CRL in 52 (45.2%). The combined immunohistochemical analysis of CRL and/or DF3, revealed that simultaneous expression of DF3 and CRL (DF3+/CRL+) significantly correlated to lymph node metastasis and to blood vessel invasion, and that patients with DF3+/CRL+-tumors survived for a significantly shorter period after surgery than did the other three groups (DF3+/CRL-, DF3-/CRL+, and DF3-/CRL-). Multivariate analysis showed independent prognostic significance for DF3+/CRL+ expression (hazard ratio [HR]=2.733, P=0.0085), and surgical cure (HR=4.334, P=0.003). To investigate the biological role of the simultaneous expression of DF3 and CRL, we constructed DF3-/CRL+ (NR-MC-38) and DF3+/CRL+ (R-MC-38) cells by transducing a mouse colon adenocarcinoma cell line MC-38 expressing neither DF3 nor CRL with MUC-1 cDNA containing ten tandem repeats (R-MC-38) or MUC-1 cDNA devoid of tandem repeats (NR-MC-38). R-MC-38 (DF3+/CRL+) cells were more invasive than NR-MC-38 (DF3-/CRL+) and MC-38 (DF3-/CRL-) cells. When these transfectants were incubated with pAb CRL, the invasiveness of R-MC-38 (DF3+/CRL+) was strikingly elevated over the case with native MC-38 (DF3-/CRL-) and NR-MC-38 (DF3-/CRL+) cells. The pAb CRL-induced invasiveness of R-MC-38 cells was inhibited by adding mAb DF3 or CRL peptides together with pAb CRL. These results suggest that an expression of DF3/MUC1 is highly associated with cell-invasiveness, and the DF3/MUC1-associated invasiveness is amplified by CRL. Thus DF3+/CRL+-MUC-1 molecule seems to be closely involved in a poor prognosis for gastric cancer patients.

Induction of HLA-unrestricted and HLA-class-II-restricted cytotoxic T lymphocytes against MUC-1 from patients with colorectal carcinomas using recombinant MUC-1 vaccinia virus

We recently reported that immunization with a recombinant MUC-1 vaccinia virus (rVMUC-1) protected C57BL/6 mice from challenge with DF3/MUC-1-positive syngeneic tumors. To elucidate whether anti-MUC-1 tumor immunity, especially MUC-1-specific cytotoxic T lymphocytes (CTI), can be induced in cancer patients by rVMUC-1, we stimulated the peripheral blood lymphocytes from patients with DF3/MUC-1+ or DF3/MUC-1 colon carcinomas using the autologous monocytes infected with rVMUC-1 (rVAMN). The stimulated T lymphocytes from two patients with DF3/MUC-1-positive colorectal carcinomas (rVPY+T and rVPW+T) demonstrated HLA-unrestricted cytotoxicity against MUC-1, whereas those from the patient with DF3/MUC-1-negative colon carcinoma (rVPA-T) did not. The HLA-unrestricted cytotoxicity was demonstrated by the CD8+ T cells possibly recognizing an epitope present on the tandem repeats. Adoptive immunotherapy who performed three times with patient PY, at 4-week intervals. The adoptive transfer of the first stimulated lymphocytes, demonstrating a high level of HLA-unrestricted cytotoxicity against MUC-1, resulted in the significant reduction of the liver metastasis of patient PY. However, HLA-unrestricted cytotoxicity against MUC-1 was extremely reduced at the second transfer and finally eliminated at the third, whereas the CD4+ T cells demonstrating HLA-class-II-restricted cytotoxicity against MUC-1 predominantly proliferated at the third adoptive immunotherapy treatment. The liver metastasis and the serum levels of tumor markers (carcinoembryonic antigen CA19-9) demonstrated a rapid and marked increment after the second transfer and especially after the third. These results suggest that the HLA-unrestricted cytotoxic CD8+ T cells against MUC-1, induced in patients with DF3/MUC-1+ colorectal carcinomas using rVMUC-1, correlate with the antitumor activity in vivo.

EBI1-ligand chemokine (ELC) attracts a broad spectrum of lymphocytes: activated T cells strongly up-regulate CCR7 and efficiently migrate toward ELC

EBI1-ligand chemokine (ELC) is a CC chemokine constitutively expressed in various lymphoid tissues and a high-affinity functional ligand for EBI1/CCR7, a seven transmembrane G-protein-coupled receptor originally identified as an Epstein-Barr virus (EBV)-inducible gene. Here we examined chemotactic activity of ELC on peripheral blood leukocytes. ELC attracted both CD4+ and CD8+ T cells, particularly efficiently after activation with IL-2 or with phytohemagglutinin (PHA) plus IL-2, as well as CD19+ B cells, but not CD16+ NK cells, CD14+ monocytes or neutrophils. Among CD3+ T cells, ELC attracted both CD45RO- naive and CD45RO+ memory subsets. ELC also induced vigorous calcium mobilization in T cells stimulated with IL-2 with an ED50 of 3 nM. ELC fused with the secreted form of alkaline phosphatase (ELC-SEAP) specifically bound to lymphocytes and this binding was blocked only by ELC among 10 CC chemokines so far tested. Notably, lymphocytes stimulated with IL-2 or T cells expanded by PHA plus IL-2 showed much higher levels of binding than fresh lymphocytes. Consistently, CCR7 mRNA was detected in CD4+ and CD8+ T cells as well as B cells, but not in NK cells, monocytes or neutrophils, and was dramatically increased in T cells upon treatment with IL-2 or with PHA plus IL-2. Like ELC mRNA, CCR7 mRNA was expressed in various lymphoid tissues. By in situ hybridization, ELC and CCR7 mRNA were detected in the parafollicular and inner cortical regions of a lymph node, and in the parafollicular regions of an appendix. Collectively, ELC and CCR7 may be involved in the trafficking of a broad spectrum of lymphocytes, especially activated T cells, into and within various lymphoid tissues.

A lymphocyte-specific CC chemokine, secondary lymphoid tissue chemokine (SLC), is a highly efficient chemoattractant for B cells and activated T cells

Secondary lymphoid tissue chemokine (SLC) is a CC chemokine expressed mainly in lymph nodes, appendix and spleen, and specifically chemotactic for lymphocytes (Nagira et al., J. Biol. Chem. 1997. 272: 19518-19524). Here, we carried out transendothelial migration assays to determine the classes and subsets of lymphocytes migrating toward SLC. SLC attracted freshly isolated B cells with high efficiency and T cells modestly. Thus, SLC is the first CC chemokine with a strong chemotactic activity on fresh B cells. Among T cell types and subsets, SLC broadly attracted CD4+ and CD8+ cells, CD45RO- (naive) and CD45RO+ (memory) cells, and CD26high (activated) and CD26low- (resting) cells. SLC also attracted both L-selectin+ and L-selectin- subpopulations of various T cell subsets and B cells. Furthermore, mitogenic stimulation strongly enhanced migratory responses of T cells and B cells toward SLC. By in situ hybridization, SLC mRNA was detected in the cortical parafollicular regions (the T cell areas) of a lymph node and an appendix. Collectively, SLC may be a basic chemokine supporting homeostatic migration of a broad spectrum of lymphocytes into the secondary lymphoid tissues. SLC may also be involved in immune responses by inducing highly efficient migration of T and B cells following antigenic stimulation.

A lymphocyte-specific CC chemokine, secondary lymphoid tissue chemokine (SLC), is a highly efficient chemoattractant for B cells and activated T cells

Secondary lymphoid tissue chemokine (SLC) is a CC chemokine expressed mainly in lymph nodes, appendix and spleen, and specifically chemotactic for lymphocytes (Nagira et al., J. Biol. Chem. 1997. 272: 19518-19524). Here, we carried out transendothelial migration assays to determine the classes and subsets of lymphocytes migrating toward SLC. SLC attracted freshly isolated B cells with high efficiency and T cells modestly. Thus, SLC is the first CC chemokine with a strong chemotactic activity on fresh B cells. Among T cell types and subsets, SLC broadly attracted CD4+ and CD8+ cells, CD45RO- (naive) and CD45RO+ (memory) cells, and CD26high (activated) and CD26low- (resting) cells. SLC also attracted both L-selectin+ and L-selectin- subpopulations of various T cell subsets and B cells. Furthermore, mitogenic stimulation strongly enhanced migratory responses of T cells and B cells toward SLC. By in situ hybridization, SLC mRNA was detected in the cortical parafollicular regions (the T cell areas) of a lymph node and an appendix. Collectively, SLC may be a basic chemokine supporting homeostatic migration of a broad spectrum of lymphocytes into the secondary lymphoid tissues. SLC may also be involved in immune responses by inducing highly efficient migration of T and B cells following antigenic stimulation.

Signal transduction pathway of the induction of cell motility in hamster pancreatic ductal adenocarcinoma cell

Recently, we reported that low (PC-1)- and high-invasive cell lines (PC-1.0) were established on the basis of hamster pancreatic ductal adenocarcinomas, and PC-1.0 cells were secreting the dissociation factor in the supernatant (DF-CM) which induced cell dissociation and enhancement of cell motility. The cell motility of PC-1.0 is about 6 times as high as that of PC-1, which was continuously maintained in an autocrine fashion by DF-CM. In contrast, cell motility of PC-1 was rapidly induced by DF-CM with a high level of induction of endogenous c-fos mRNA and returned to a basal level within 6 h. The inhibition experiment using antisense oligonucleotides to c-fos indicated that the high level of induction of c-fos mRNA observed in the DF-CM-treated PC-1 cells was closely associated with their induction of cell motility. To elucidate these differences of responses against DF-CM between PC-1 and PC-1.0, signal transduction pathways of induction of the cell motilities were analyzed, using protein kinase C (PKC) inhibitor, 12-O-tetradecanoylphorbol-13-acetate, cyclic AMP antagonist, and cyclic AMP agonist. The transiently enhanced cell motility of DF-CM-treated PC-1 cells was completely inhibited by the cyclic AMP antagonist, and the cyclic AMP agonist was able to induce a similar pattern of induction of cell motility in PC-1 cells to DF-CM. On the other hand, the highly enhanced cell motility of PC-1.0 was completely inhibited by protein kinase C inhibitor, but not by cyclic AMP antagonist. These results suggest that cell motility of low-invasive PC-1 cells is under control through cyclic AMP-dependent protein kinase A, while the protein kinase C pathway seems favorable for high-invasive PC-1.0 cells to maintain the continuously enhanced cell motility responsible for their high invasiveness.

Therapeutic antitumor response after immunization with an admixture of recombinant vaccinia viruses expressing a modified MUC1 gene and the murine T-cell costimulatory molecule B7

Tumor-associated antigens have considerable promise not only as diagnostic or prognostic markers but also as targets for active or passive immunotherapy. DF3/MUC1 is a tumor-associated antigen that is overexpressed with an abnormal glycosylation pattern in breast, ovarian, lung, and pancreatic cancers. The major extracellular portion of MUC1 is composed of tandem repeat units of 20 amino acids. Recombinant vaccinia viruses encoding mucin molecules have been constructed by several groups. However, these recombinants have met with limited success in protecting animals from MUC1-expressing tumors because of the vaccinia genome being subject to high-frequency homologous recombination, therefore being unstable in expression of the tandem repeats. In light of these studies, two concurrent strategies were used to improve immune responses to MUC1: a recombinant vaccinia virus was constructed containing a modified "mini" MUC1 gene containing only 10 tandem repeat sequences to minimize vaccinia-mediated rearrangement (designated rV-MUC1); and an admixture was used containing rV-MUC1 and a recombinant vaccinia virus containing the gene for the murine T-cell costimulatory molecule B7-1 (rV-B7). The rV-MUC1 gene product maintained a consistent molecular weight throughout several passages, indicating stability of the inserted gene. Mice inoculated with rV-MUC1 demonstrated MUC1-specific cytolytic responses that were further enhanced by admixture with rV-B7. In a MUC1-expressing pulmonary metastases prevention model, mice inoculated two times with rV-MUC1 were protected from the establishment of metastases. No additive effect on antitumor immunity (> 90% with rV-MUC1 alone) was observed in mice primed with an admixture of rV-MUC1 and rV-B7 and boosted with rV-MUC1. When rV-MUC1 was used to treat established MUC1 positive metastases, however, three administrations of rV-MUC1 were not sufficient to confer antitumor effects. In contrast, when tumor-bearing mice were primed with an admixture of rV-MUC1 and rV-B7, followed by two boosts with rV-MUC1, there was a significant reduction in pulmonary metastases (p = < 0.0001), which correlated to 100% survival. Coexpression of the B7 molecule, although not necessary for the induction of an immune response of sufficient magnitude to prevent MUC1 tumors, was thus essential in a treatment setting.

Production of group II phospholipase A(2) in advanced gastric cancer

We examined the immunohistochemical expression of membrane-associated phospholipase A(2) (M-PLA(2)), belonging to group II PLA(2), in 44 advanced gastric cancers, using the ABC method and monoclonal antibody anti-human M-PLA(2). M-PLA(2) mRNA was also examined in the same rumours by Northern blot analysis. In addition, the content of M-PLA(2) protein and prostaglandin E(2) (PGE(2)) in the malignant lesion and in the non-malignant gastric mucosa was examined. The expression was detected in cancer cells in 31 out of 44 advanced gastric cancer tissues (70.4%) by the ABC method. M-PLA(2) mRNA was detected in 36 out of 44 gastric cancer tissues (81.8%), and the density was observed to be higher in tumour tissues than in the adjacent nonmalignant gastric mucosa. The M-PLA(2) protein was detected both in malignant tissues and in non-malignant gastric mucosa, and the content of M-PLA(2) protein was significantly higher in malignant tissues than in the non-malignant gastric mucosa. There was a significant positive correlation between the expression of M-PLA(2) mRNA and the amount of M-PLA(2) protein. PGE, was also detected in the malignant tissues and in the non-malignant mucosa. The content of PGE, was significantly higher in the former. These results indicate that M-PLA(2) is produced both in malignant and nonmalignant cells of the stomach, the former producing higher amounts of this enzyme than the latter. M-PLA(2) may be involved in cancer progression through its function or through the function of products of this enzyme's action such as PGE(2) in gastric cancer.

Characterization of cancer cell dissociation factor in a highly invasive pancreatic cancer cell line

BACKGROUND

Two pancreatic cancer cell lines, the highly invasive and metastatic cell line PC-1.0 and the weakly invasive and rarely metastatic cell line PC-1, were established from a pancreatic ductal carcinoma induced by N-nitrosobis (2-oxopropyl) amine in a Syrian golden hamster.

METHODS

The cancer cell dissociation activity in serum-free conditioned medium of PC-1.0 cells was partially purified using a heparin column, a hydroxylapatite column, anion exchange, and gel filtration high-performance liquid chromatography. Several biologic properties of the partially purified activity were evaluated.

RESULTS

Two cell lines exhibited different growth morphologic changes in vitro: the weakly invasive cell line PC-1 formed islandlike colonies, and the highly invasive cell line PC-1.0 grew mainly as single cells. The conditioned medium of PC-1.0 cells induced dissociation of islandlike colonies and morphologic changes of PC-1 cells to elongated cells, with a high frequency of pseudopodia formation similar to the morphologic findings of PC-1.0 cells. The dissociation activity did not bind to the heparin column and had an apparent molecular mass of > 400 kDa, as deduced from gel filtration. Several immunoreactive proteinous bands were observed in immunoblotting analysis using a polyclonal blocking antibody. The partially purified activity enhanced cell motility, chemoinvasion, and cell adhesion to plastic plates and fibronectin.

CONCLUSIONS

Highly invasive and metastatic PC-1.0 cells produce a soluble proteinous factor, called "dissociation factor" (DF), which induces cell dissociation of weakly invasive and rarely metastatic PC-1 cells. It seems likely that DF has a role in tumor invasion and metastasis.

Messenger RNA expressed in mouse teratocarcinoma stem cells and down-regulated by a tumor-promoting phorbol ester codes for a novel transmembrane protein

Cloning and sequence analysis of a DNA complementary to the mRNA expressed in undifferentiated mouse F9 teratocarcinoma stem cells but disappearing rapidly after treatment with a tumor-promoting phorbol ester revealed it to be a 1.9 kilobase pairs-long cDNA encoding a protein of 323 amino acid residues. Computer-assisted analyses of the deduced amino acid sequence indicated that this protein contains a typical hydrophobic signal peptide consisting of 33 amino acid residues and six putative membrane-spanning segments. The deduced amino acid sequence, as a whole, bears no significant sequence homology to any previously described protein.

Isolation of complementary DNA clones for genes exhibiting reduced expression after treatment of mouse teratocarcinoma stem cells with a tumor-promoting phorbol ester

For the study of the effects of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) on early mammalian cell differentiation, a complementary DNA (cDNA) library was constructed on the poly(A)+RNAs extracted from undifferentiated F9 cells derived from a 129/Sv mouse teratocarcinoma OTT6050, and screening was done for the cNDA sequences corresponding to the mRNAs, the levels of which decreased significantly in the F9 cells after the TPA treatment. From about 80,000 clones screened, 3 different cDNA clones, pFT27, pFT43, and pFT60, were isolated and characterized. Levels of the RNAs hybridizable to these clones were decreased by fourfold to more than fiftyfold within 1-10 hours in the presence of TPA. Northern blotting experiments identified transcripts corresponding to these clones: pFT27 hybridized to 3.0 kb RNA, pFT43 hybridized to 1.5 kb RNA, and pFT60 hybridized to 1.0 kb RNA. The levels of these 3 transcripts were also decreased after treatment of the undifferentiated F9 cells with retinoic acid (RA) and dibutyryl cyclic AMP (cAMP). The TPA-induced as well as the RA- and cAMP-induced decreases in the RNAs hybridizable to pFT27 were regulated at the transcriptional level, whereas similar decreases in the RNAs hybridizable to pFT43 and pFT60 were regulated at the post-transcriptional level. These findings show that TPA treatment shares common effects with RA and cAMP on the undifferentiated F9 cells.