Impact of pathological nodal staging and tumour differentiation on survival and postoperative radiotherapy in completely resected stage IIIA Non-small-cell lung cancer

BACKGROUND

Tumour differentiation is an important index for adjuvant therapy in many cancers; however, non-small cell lung cancer (NSCLC) is an exception. Furthermore, postoperative radiotherapy (PORT) is controversial in patients with NSCLC with N0-1 and N2 disease. We aimed to evaluate the impact of tumour-related factors on overall survival (OS), cancer-specific survival (CSS), and distant control (DC) in patients with completely resected stage IIIA NSCLC.

MATERIALS AND METHODS

Patients with stage IIIA non-metastatic NSCLC who underwent complete resection and adjuvant chemotherapy were identified from the Taiwan Cancer Registry (January 2007-December 2017). Logistic regression analysis was performed to determine the factors associated with PORT. Survival and relapse outcomes were compared using log-rank tests and Cox regression analysis. Sensitivity analysis was performed using propensity score-matched pairs.

RESULTS

In total, 1,897 patients were included and stratified according to PORT use (PORT vs. non-PORT). After adjusting for covariates, PORT was not found to be associated with improved survival outcomes. In patients with poorly differentiated tumours and N2 disease, absolute benefits for OS (adjusted hazard ratio [aHR] 0.76), CSS (aHR 0.80), and DC (aHR 0.74) were observed. Multivariable hazard models of propensity score-matched pN2 disease and poorly differentiated tumour subgroups also showed significant survival benefit with PORT treatment.

CONCLUSIONS

Patients with poorly differentiated tumours and receiving PORT for pN2 disease showed a lower risk of distant recurrence and more favourable survival outcomes in stage IIIA NSCLC with R0 resection.

Carbohydrate Antigen 19-9 Response to Initial Adjuvant Chemotherapy Predicts Survival and Failure Pattern of Resected Pancreatic Adenocarcinoma but Not Which Patients Are Suited for Additional Adjuvant Chemoradiation Therapy: From a Prospective Randomized Study

PURPOSE

The predictive value of carbohydrate antigen 19-9 (CA19-9) for adjuvant chemo(radiation) therapy of resected pancreatic adenocarcinoma (PDAC) is undefined.

METHODS AND MATERIALS

We analyzed CA19-9 levels in patients with resected PDAC in a prospective randomized trial of adjuvant chemotherapy with or without additional chemoradiation therapy (CRT). Patients with postoperative CA19-9 ≤92.5 U/mL and serum bilirubin ≤2 mg/dL were randomized to 2 arms: patients in 1 arm received 6 cycles of gemcitabine, whereas those in the other received 3 cycles of gemcitabine followed by CRT and another 3 cycles of gemcitabine. Serum CA19-9 was measured every 12 weeks. Those who had CA19-9 levels always <3 U/mL were excluded from the exploratory analysis.

RESULTS

One hundred forty-seven patients were enrolled in this randomized trial. Twenty-two patients with CA19-9 levels always ≤3 U/mL were excluded from the analysis. For the 125 participants, median overall survival (OS) and recurrence-free survival were 23.1 and 12.1 months, respectively, with no significant differences between the study arms. Postresection CA19-9 levels and, to a lesser extent, CA19-9 change predicted OS (P = .040 and .077, respectively). For the 89 patients who completed the initial 3 cycles of adjuvant gemcitabine, the CA19-9 response was significantly correlated with initial failure over the distant site (P = .023) and OS (P = .0022). Despite a trend of less initial failure over the locoregional area (P = .031), neither postoperative CA19-9 level nor CA19-9 response helped to select patients who might have a survival benefit from additional adjuvant CRT.

CONCLUSIONS

CA19-9 response to initial adjuvant gemcitabine predicts survival and distant failure of PDAC after resection; however, it cannot select patients suited for additional adjuvant CRT. Monitoring CA19-9 levels during adjuvant therapy for postoperative patients with PDAC may guide therapeutic decisions to prevent distant failure.

Krüppel-like factor 10 modulates stem cell phenotypes of pancreatic adenocarcinoma by transcriptionally regulating notch receptors

BACKGROUND

Pancreatic adenocarcinoma (PDAC) is well known for its rapid distant metastasis and local destructive behavior. Loss of Krüppel-like factor 10 (KLF10) contributes to distant migration of PDAC. The role of KLF10 in modulating tumorigenesis and stem cell phenotypes of PDAC is unclear.

METHODS

Additional depletion of KLF10 in KC (LSL: Kras^G12D; Pdx1-Cre) mice, a spontaneous murine PDAC model, was established to evaluate tumorigenesis. Tumor specimens of PDAC patients were immune-stained of KLF10 to correlate with local recurrence after curative resection. Conditional overexpressing KLF10 in MiaPaCa and stably depleting KLF10 in Panc-1 (Panc-1-pLKO-shKLF10) cells were established for evaluating sphere formation, stem cell markers expression and tumor growth. The signal pathways modulated by KLF10 for PDAC stem cell phenotypes were disclosed by microarray analysis and validated by western blot, qRT-PCR, luciferase reporter assay. Candidate targets to reverse PDAC tumor growth were demonstrated in murine model.

RESULTS

KLF10, deficient in two-thirds of 105 patients with resected pancreatic PDAC, was associated with rapid local recurrence and large tumor size. Additional KLF10 depletion in KC mice accelerated progression from pancreatic intraepithelial neoplasia to PDAC. Increased sphere formation, expression of stem cell markers, and tumor growth were observed in Panc-1-pLKO-shKLF10 compared with vector control. Genetically or pharmacologically overexpression of KLF10 reversed the stem cell phenotypes induced by KLF10 depletion. Ingenuity pathway analysis and gene set enrichment analysis showed that Notch signaling molecules, including Notch receptors 3 and 4, were over-expressed in Panc-1-pLKO-shKLF10. KLF10 transcriptionally suppressed Notch-3 and -4 by competing with E74-like ETS transcription factor 3, a positive regulator, for promoter binding. Downregulation of Notch signaling, either genetically or pharmacologically, ameliorated the stem cell phenotypes of Panc-1-pLKO-shKLF10. The combination of metformin, which upregulated KLF10 expression via phosphorylating AMPK, and evodiamine, a non-toxic Notch-3 methylation stimulator, delayed tumor growth of PDAC with KLF10 deficiency in mice without prominent toxicity.

CONCLUSIONS

These results demonstrated a novel signaling pathway by which KLF10 modulates stem cell phenotypes in PDAC through transcriptionally regulating Notch signaling pathway. The elevation of KLF10 and suppression of Notch signaling may jointly reduce PDAC tumorigenesis and malignant progression.

A phase II randomised trial of induction chemotherapy followed by concurrent chemoradiotherapy in locally advanced pancreatic cancer: the Taiwan Cooperative Oncology Group T2212 study

BACKGROUND

The objective of this study was to evaluate the efficacy and safety of induction chemotherapy (ICT), GOFL (gemcitabine, oxaliplatin plus fluorouracil (5-FU)/leucovorin) versus modified FOLFIRINOX (irinotecan, oxaliplatin plus 5-FU/leucovorin), followed by concurrent chemoradiotherapy (CCRT) in locally advanced pancreatic adenocarcinoma (LAPC).

METHODS

Chemo-naive patients with measurable LAPC were eligible and randomly assigned to receive biweekly ICT with either mFOLFIRINOX or GOFL for 3 months. Patients without systemic progression would have 5-FU- or gemcitabine-based CCRT (5040 cGy/28 fractions) and were then subjected to surgery or continuation of chemotherapy until treatment failure. The primary endpoint was 9-month progression-free survival (PFS) rate.

RESULTS

Between July 2013 and January 2019, 55 patients were enrolled. After ICT, 21 (77.8%) of 27 patients who received mFOLFIRINOX and 17 (60.7%) of 28 patients who received GOFL completed CCRT. Of them, one and five had per-protocol R0/R1 resection. On intent-to-treat analysis, the 9-month PFS rate, median PFS and overall survival in mFOLFIRINOX and GOFL arms were 30.5% versus 35.9%, 6.6 (95% confidence interval: 5.9-12.5) versus 7.6 months (3.9-12.3) and 19.6 (13.4-22.9) versus 17.9 months (13.4-23.9), respectively. Grade 3-4 neutropenia and diarrhoea during induction mFOLFIRINOX and GOFL were 37.0% versus 21.4% and 14.8% versus 3.6%, respectively.

CONCLUSION

Induction GOFL and mFOLFIRINOX followed by CCRT provided similar clinical outcomes in LAPC patients. CLINICALTRIAL.

GOV IDENTIFIER

NCT01867892.

High expression of krüppel-like factor 10 or Smad4 predicts clinical benefit of adjuvant chemoradiotherapy in curatively resected pancreatic adenocarcinoma: From a randomized phase III trial

PURPOSE

Our previous studies have demonstrated that Krüppel-like factor 10 (Klf10) modulated tumor radiation resistance and helps to predict clinical outcomes of pancreatic adenocarcinoma (PDAC). This study aimed to evaluate whether the expression levels of Klf10, Smad4 and Runx3 can help predict the benefits of adjuvant chemoradiotherapy (CRT) in resected PDAC.

METHODS AND MATERIALS

Tissue specimens were collected from 111 patients with curatively resected PDAC who were enrolled into a randomized trial comparing adjuvant gemcitabine with or without CRT. Immunohistochemical expression of biomarkers was quantified by pathologists blinded to patient outcomes through a grading system based on the extent and intensity of staining. The predictive value of biomarkers was analyzed using SAS statistical software.

RESULTS

In total, 56 and 55 patients received adjuvant gemcitabine alone and additional CRT, respectively. The expression levels of Klf10, Smad4 and postoperative CA19-9 were significantly correlated with overall survival (OS) (p = 0.013, 0.045, and 0.047, respectively). Multivariable analysis showed that the expression level of postoperative serum CA19-9 and tumor tissue Klf10 expression level were significant predictors for OS (p = 0.038, and 0.028, respectively). Patients with high Klf10 or Smad4 (n = 55), had a significantly better local recurrence-free survival (∞ vs 19.8 months; p = 0.026) and a longer OS (33.0 vs 23.0 months; p = 0.12) if they received additional adjuvant CRT than gemcitabine only. The results were similar after adjusted by postoperative level of CA19-9.

CONCLUSION

Patients with curatively resected PDAC and a high expression of either Klf10 or Smad4 have high chances of benefiting from adjuvant CRT. Combining Klf10 and Smad4 to predict the benefits of adjuvant CRT in resected PDAC deserves further validation.

Abstract C11: Linoleic acid elevates sirtuin 6 expression and modulates glycolysis and epithelial-mesenchymal transition of pancreatic cancer with loss of Krüpple like factor 10

Introduction: Pancreatic adenocarcinoma (PDAC) is well known for its deregulated TGFβ signaling. TGFβ signaling exerts a contextual effect that suppresses malignant growth early in epithelial tumorigenesis but promotes metastasis at later stages. The Krüppel-like factor 10 (Klf10) is an early response gene that mediates the antiproliferative effects of TGFβ but opposes the prometastatic effects of TGFβ by limiting its ability to induce epithelial-to-mesenchymal transition (EMT). The distinction between the antiproliferative versus prometastatic functions of TGFβ makes Klf10 a potential target for the development of therapy in cancers with aberrant TGFβ pathway such as PDAC. Klf10 knock-out mice do not have abnormal pancreas development or carcinogenesis. However, ablating Klf10 in murine PDAC models increases pancreatic tumorigenesis and distant metastasis. Genome-wide comparison of mRNA profiles from wild-type and Klf10 knock-out mice revealed significant enrichment for transcripts involved in glucose metabolism. We propose that Klf10 modulates PDAC progression via enhanced glycolysis, which leads to EMT and cancer stemness phenotypes.

Materials and Methods: Genetically manipulated Klf10 of human PDAC cell lines was established to measure EMT markers, glycolysis activity and stemness related proteins, cell migration, and murine liver metastasis after intrasplenic injection. Chip-Chip assay was performed to find sirtuin 6 (Sirt6), governing both cancer metabolism and progression, to be one of the candidate molecules regulated by Klf10. The interaction between Klf10 and Sirt6 was evaluated by ChIP-PCR and luciferase reporter assay. PDAC cell lines with or without Klf10 mRNA silencing were overexpressed with Sirt6 to reverse malignant phenotypes induced by Klf10 deficiency. Linoleic acid, a specific Sirt6 activator, was used in vitro and in vivo to ameliorate the aberrant glucose metabolism, EMT phenotype, and distant metastasis of PDAC with loss of Klf10 expression.

Results: In vitro and in vivo studies demonstrated Klf10 deficiency in pancreatic cancer enhanced metastasis, EMT, stemness, and glycolysis. Klf10 bond to the promoter and transcriptionally regulated Sirt6. Sirt6 expression paralleled the level of Klf10 in PDAC. Modulating Sirt6 genetically or pharmacologically, by linoleic acid, reversed the EMT, glycolysis, and metastatic phenotypes of PDAC with KLF10 deficiency. Using PDK1, a glycolysis inhibitor, and BSI#38, an EMT inhibitor, we demonstrated the interaction of cancer metabolism and EMT phenotypes in PDAC.

Discussion: Loss of Klf10 contributes to pancreatic cancer progression and enhances glycolysis, EMT, and cancer stemness by transcriptionally regulating Sirt6. Overexpressing Sirt6 genetically or pharmacologically by linoleic acid may ameliorate PDAC progression. Targeting Klf10/Sirt6 signaling is a potential strategy to modulate glycolysis and EMT simultaneously in PDAC for preventing malignant progression.

Citation Format: Hui-Ju Ch'ang, Yi-Chih Tsai, Su-Liang Chen, Vincent H.S. Chang. Linoleic acid elevates sirtuin 6 expression and modulates glycolysis and epithelial-mesenchymal transition of pancreatic cancer with loss of Krüpple like factor 10 [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2019 Sept 6-9; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2019;79(24 Suppl):Abstract nr C11.

Therapeutic Effect of Repurposed Temsirolimus in Lung Adenocarcinoma Model

Lung cancer is one of the major cause of cancer-related deaths worldwide. The poor prognosis and resistance to both radiation and chemotherapy urged the development of potential targets for lung cancer treatment. In this study, using a network-based cellular signature bioinformatics approach, we repurposed a clinically approved mTOR inhibitor for renal cell carcinomans, temsirolimus, as the potential therapeutic candidate for lung adenocarcinoma. The PI3K-AKT-mTOR pathway is known as one of the most frequently dysregulated pathway in cancers, including non-small-cell lung cancer. By using a well-documented lung adenocarcinoma mouse model of human pathophysiology, we examined the effect of temsirolimus on the growth of lung adenocarcinoma in vitro and in vivo. In addition, temsirolimus combined with reduced doses of cisplatin and gemcitabine significantly inhibited the lung tumor growth in the lung adenocarcinoma mouse model compared with the temsirolimus alone or the conventional cisplatin–gemcitabine combination. Functional imaging techniques and microscopic analyses were used to reveal the response mechanisms. Extensive immunohistochemical analyses were used to demonstrate the apparent effects of combined treatments on tumor architecture, vasculature, apoptosis, and the mTOR-pathway. The present findings urge the further exploration of temsirolimus in combination with chemotherapy for treating lung adenocarcinoma.

The Role of Consolidation Chemoradiotherapy in Locally Advanced Pancreatic Cancer Receiving Chemotherapy: An Updated Systematic Review and Meta-Analysis

Purpose

The role of consolidation chemoradiation (CCRT) after systemic chemotherapy in locally advanced pancreatic cancer (LAPC) is still controversial. We aim to evaluate the effectiveness of CCRT in LAPC using systematic review and meta-analysis of prospective studies.

Materials and Methods

Prospective clinical trials of LAPC receiving chemotherapy with or without subsequent CCRT were included in the analysis. We systematically searched in PubMed, MEDLINE, Embase, and Web of Science. The primary outcome of interest was 1-year survival. Secondary endpoints were median overall survival, progression-free survival, toxicity, and resection rate.

Results

Forty-one studies with 49 study arms were included with a total of 1,018 patients receiving CCRT after induction chemotherapy (ICT) and 954 patients receiving chemotherapy alone. CCRT after ICT did not improve 1-year survival significantly in LAPC patients compared with chemotherapy alone (58% vs. 52%). ICT lasted for at least 3 months revealed significantly improved survival of additional CCRT to LAPC patients compared to chemotherapy alone (65% vs. 52%). A marginal survival benefit of consolidation CCRT was noted in studies using maintenance chemotherapy (59% vs. 52%), and fluorouracil-based CCRT (64% vs. 52%), as well as in studies conducted after the 2010 (64% vs. 55%).

Conclusion

The survival benefit of ICT+CCRT over chemotherapy alone in treating LAPC was noted when ICT lasted for at least 3 months. Fluorouracil-based CCRT, and maintenance chemotherapy were associated with improved clinical outcomes.

Second malignant neoplasms in a nationwide population-based cohort of childhood cancer survivors in Taiwan

10569

Background: Childhood cancer survivors have excess risk of second malignant neoplasms, but data are limited in Asian populations. We established a nationwide retrospective cohort of childhood cancer survivors in Taiwan to study the risk of second malignant neoplasms in the population. Methods: Children and adolescents diagnosed with cancer before age 21 years between 1990 and 2011 were identified from the Taiwan Cancer Registry, the national cancer registry in Taiwan. One-year survivors of childhood cancer were ascertained through data linkage with the national death registry. Survivors were followed up through December 2012. Standardized incidence ratios (SIRs), absolute excess risks (AERs), and cumulative incidence of second malignant neoplasms were calculated. Results: A total of 186 second malignant neoplasms occurred among 15,263 1-year survivors of childhood cancer after a mean follow-up time of 8.0 years (SIR = 5.4, 95% confidence interval [CI] = 4.6-6.2; AER = 12.4 per 10,000 person-years). The most common types of second malignant neoplasms were gastrointestinal cancers (n = 37), leukemia (n = 28), endocrine cancers (n = 18), and brain cancer (n = 17). Cancers in the liver (n = 11, including 9 hepatocellular carcinoma) and colorectum (n = 16) accounted for 73% of second gastrointestinal malignant neoplasms in this population. The cumulative incidence of second malignant neoplasms at 10 and 20 years from follow-up was 1.0% (95% CI = 0.8-1.2%) and 3.0% (95% CI = 2.3-3.6%), respectively. Conclusions: Childhood cancer survivors in Taiwan experience excess risk of second malignant neoplasms, in particular gastrointestinal cancers, compared with the general population.

Krüpple-like factor 10 regulates radio-sensitivity of pancreatic cancer via UV radiation resistance-associated gene

BACKGROUND AND PURPOSE

Krüpple-like factor 10 (Klf10), an early response gene of TGFβ, was reported to be a prognostic biomarker for pancreatic cancer survival. The role of Klf10 in predicting tumor response to cancer treatment is unknown.

MATERIALS AND METHODS

Genetically manipulated MiaPaCa and Panc-1 cells were established to evaluate clonogenic survival, autophagy, apoptosis and DNA repair after radiation. The interaction between Klf10 and UV radiation resistance-associated gene (UVRAG) was demonstrated by ChiP-PCR and luciferase reporter assay. Orthotopic murine tumor model and clinical specimens were used to evaluate radio-sensitivity of pancreatic cancer.

RESULTS

We found Klf10 silencing correlates with enhanced pancreatic cancer clonogenic survival and murine tumor growth after radiation. UVRAG was an essential down-stream mediator transcriptionally suppressed by Klf10. Silencing UVRAG mRNA in Klf10 depleted Panc-1 cells reversed the radio-resistant phenotypes including decreased apoptosis and enhanced DNA repair as well as autophagy. Metformin, an anti-diabetic agent, was found to increase Klf10 and suppress UVRAG expression to improve radiation cytotoxicity in pancreatic cancer. The predictive value of Klf10 in radiation response and the inverse correlation with UVRAG were confirmed in cohorts of pancreatic cancer patients.

CONCLUSIONS

Klf10 is a potential biomarker in predicting and sensitizing radiation effect in pancreatic cancer.

A phase I clinical study of immunotherapy for advanced colorectal cancers using carcinoembryonic antigen-pulsed dendritic cells mixed with tetanus toxoid and subsequent IL-2 treatment

BACKGROUND

To better evaluate and improve the efficacy of dendritic cell (DC)-based cancer immunotherapy, we conducted a clinical study of patients with advanced colorectal cancer using carcinoembryonic antigen (CEA)-pulsed DCs mixed with tetanus toxoid and subsequent interleukin-2 treatment. The tetanus toxoid in the vaccine preparation serves as an adjuvant and provides a non-tumor specific immune response to enhance vaccine efficacy. The aims of this study were to (1) evaluate the toxicity of this treatment, (2) observe the clinical responses of vaccinated patients, and (3) investigate the immune responses of patients against CEA before and after treatment.

METHODS

Twelve patients were recruited and treated in this phase I clinical study. These patients all had metastatic colorectal cancer and failed standard chemotherapy. We first subcutaneously immunized patients with metastatic colorectal cancer with 1 × 10(6) CEA-pulsed DCs mixed with tetanus toxoid as an adjuvant. Patients received 3 successive injections with 1 × 10(6) CEA-pulsed DCs alone. Low-dose interleukin-2 was administered subcutaneously following the final DC vaccination to boost the growth of T cells. Patients were evaluated for adverse event and clinical status. Blood samples collected before, during, and after treatment were analyzed for T cell proliferation responses against CEA.

RESULTS

No severe treatment-related side effects or toxicity was observed in patients who received the regular 4 DC vaccine injections. Two patients had stable disease and 10 patients showed disease progression. A statistically significant increase in proliferation against CEA by T cells collected after vaccination was observed in 2 of 9 patients.

CONCLUSIONS

The results of this study indicate that it is feasible and safe to treat colorectal cancer patients using this protocol. An increase in the anti-CEA immune response and a clinical benefit was observed in a small fraction of patients. This treatment protocol should be further evaluated in additional colorectal cancer patients with modifications to enhance T cell responses.

TRIAL REGISTRATION

ClinicalTrials.gov (identifier NCT00154713 ), September 8, 2005.

Bone marrow derived macrophages fuse with intestine stromal cells and contribute to chronic fibrosis after radiation

BACKGROUND AND PURPOSE

Bone marrow-derived cells (BMDC) have been demonstrated to play a critical role in intestine regeneration. However, organ fibrosis was one of the major side effects of bone marrow (BM) transplantation. It warrants further investigation on the mechanisms of BM cell therapy in radiation induced intestine damage.

MATERIALS AND METHODS

We established three murine models to evaluate BMDC within intestines after radiation, including cre-loxP system of transgenic mice. In vitro co-culture between murine BM with human intestine stromal cells was also performed to measure the level of fusion and fibrosis after treatment with anti-fibrotic agents or after macrophage depletion.

RESULTS

Despite complete recovery of epithelial mucosa from radiation damage, we found persistent proliferation and repopulation of BMDC within the lamina propria. Fusion between BM derived monocytic and intestine stromal cells correlated with the level of fibrosis and proliferation index. Depleting macrophages genetically using CD11b-DTR mouse model or pharmacologically using clodronate liposome reduced the level of cell fusion and intestine fibrosis.

CONCLUSIONS

Fibrotic cues from intestine enhance fusion between BM-derived monocytes/macrophages with intestine stromal cells. The fusion hybrids promote cell cycle re-entry, proliferation and reinforce fibrosis signal. Depleting macrophages interferes with cell fusion and ameliorates radiation-induced intestine fibrosis.

Optimal combination of antiangiogenic therapy for hepatocellular carcinoma

The success of sorafenib in prolonging survival of patients with hepatocellular carcinoma (HCC) makes therapeutic inhibition of angiogenesis a component of treatment for HCC. To enhance therapeutic efficacy, overcome drug resistance and reduce toxicity, combination of antiangiogenic agents with chemotherapy, radiotherapy or other targeted agents were evaluated. Nevertheless, the use of antiangiogenic therapy remains suboptimal regarding dosage, schedule and duration of therapy. The issue is further complicated by combination antiangiogenesis to other cytotoxic or biologic agents. There is no way to determine which patients are most likely respond to a given form of antiangiogenic therapy. Activation of alternative pathways associated with disease progression in patients undergoing antiangiogenic therapy has also been recognized. There is increasing importance in identifying, validating and standardizing potential response biomarkers for antiangiogenesis therapy for HCC patients. In this review, biomarkers for antiangiogenesis therapy including systemic, circulating, tissue and imaging ones are summarized. The strength and deficit of circulating and imaging biomarkers were further demonstrated by a series of studies in HCC patients receiving radiotherapy with or without thalidomide.

Circulating cells contribute to cardiomyocyte regeneration after injury

RATIONALE

The contribution of bone marrow-borne hematopoietic cells to the ischemic myocardium has been documented. However, a pivotal study reported no evidence of myocardial regeneration from hematopoietic-derived cells. The study did not take into account the possible effect of early injury-induced signaling as the test mice were parabiotically paired to partners immediately after surgery-induced myocardial injury when cross-circulation has not yet developed.

OBJECTIVE

To re-evaluate the role of circulating cells in the injured myocardium.

METHODS AND RESULTS

By combining pulse-chase labeling and parabiosis model, we show that circulating cells derived from the parabiont expressed cardiac-specific markers in the injured myocardium. Genetic fate mapping also revealed that circulating hematopoietic cells acquired cardiac cell fate by means of cell fusion and transdifferentiation.

CONCLUSIONS

These results suggest that circulating cells participate in cardiomyocyte regeneration in a mouse model of parabiosis when the circulatory system is fully developed before surgery-induced heart injury.

Abstract 3959: Depleting macrophage or blocking cell fusion machinery ameliorates intestine fibrosis after radiation

Purpose

Delayed radiation enteritis is a frequent side effect of abdominal radiotherapy. Recent studies reveal bone marrow (BM) cells repopulate damaged tissue and contribute to repair in non-hematopoietic tissues. Fusion between BM and somatic cells is enhanced by chronic inflammation. Furthermore, BM cells (BMC) can trigger fibrotic response in damaged organ. The role of cell fusion in the development of chronic intestine fibrosis after radiotherapy needs further investigation.

Materials and Methods

To evaluate cell fusion and fibrosis, gender-mismatched BM transplantation (BMT) were used. Immunoblots of macrophage fusion receptor (MFR), CD47 and fibronectin, connective tissue growth factor (CCN2) were measured. BMT with CD11b (+), CD3 (+) or B220 (+) enriched BMC were applied. The mice were treated with macrophage depleting agents, clodronate liposome, after radiotherapy and BMT. In vitro co-culture study of human intestine stromal and mouse BMC was established. Furthermore, we used Rac 1 inhibitor, MMP9 neutralizing antibody and siRNA of MFR within co-culture system and animal model.

Results

Using triple stains of Y chromosome fluorescence in situ hybridization, GFP and hematopoietic cell markers including F4/80, CD3, B220, we found BM derived macrophages contributed majorly to cell fusion (63.4%, 47.5% and 9.6%, respectively, p=0.033) within intestine of mice after radiotherapy and BMT. The fusion within intestine decreased 57% after treatment with clodronate liposome. BMT from CD11b(+), CD3(+) or B220(+) enriched donor BMC also revealed prominent fusion only in mice receiving CD11b(+) one. The level of intestine fibrosis was decreased by clodronate liposome or BMT of CD11b(-) BMC. In vitro study showed the rate of fusion decreased from 12.8% to 6.8% between intestine stromal cells with CD11b (-) compared to that with whole mouse BMCs. Fusion rate could be increased by increasing CD11b(+) BMCs (3.5% to 19.7%). Using Rac1 inhibitor, MMP9 antibody or MFR siRNA, the fusion rate decreased (19.7% to 4.6%; 11.8% to 5.6%; 31% to 19.6%, respectively). The expression of fibronectin, CCN2, MFR and CD47 paralleled the findings of fusion. Using MMP9 neutralizing antibody in mice receiving radiotherapy and BMT, we found decreased cell fusion and fibrosis within intestine.

Conclusions

BM derived CD11b(+) myelomonocytic cells or macrophage contribute majorly to cell fusion and fibrosis within intestine of mice after radiotherapy Depleting macrophage or targeting cell fusion machinery of macrophage suppresses intestine fibrosis after radiotherapy. Our study impacts not only for developing novel therapies to prevent radiation enteritis but also to avoid fibrosis after BM cell therapy in organ dysfunction.

Citation Format: Ya-Hui Chang, Hui-Ju Ch'ang, Li-Mei Lin. Depleting macrophage or blocking cell fusion machinery ameliorates intestine fibrosis after radiation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3959. doi:10.1158/1538-7445.AM2014-3959

Radiation sensitization of tumor cells induced by shear stress: the roles of integrins and FAK

Recent studies revealed that the interstitial fluid flow in and around tumor tissue not only played an important role in delivering anticancer agents, but also affected the microenvironment, mostly hypoxia, in modulating tumor radio-sensitivity. The current study investigated the hypoxia-independent mechanisms of flow-induced shear stress in sensitizing tumors to radiation. Colon cancer cells were seeded onto glass slides pre-coated with fibronectin. A parallel-plate flow chamber system was used to impose fluid shear stress. Cell proliferation, apoptosis and colony assays were measured after shear stress and/or radiation. Cell cycle analysis and immunoblots of cell adhesion signal molecules were evaluated. The effect of shear stress was reversed by modulating integrin β1 or FAK. Shear stress of 12dyne/cm(2) for 24h, but not 3h, enhanced the radiation induced cytotoxicity to colon cancer cells. Protein expression of FAK was significantly down-regulated but not transcriptionally suppressed. By modulating integrin β1 and FAK expression, we demonstrated that shear stress enhanced tumor radiosensitivity by regulating integrin β1/FAK/Akt as well as integrin β1/FAK/cortactin pathways. Shear stress in combination with radiation might regulate integrins signaling by recruiting and activating caspases 3/8 for FAK cleavage followed by ubiquitin-mediated proteasomal degradation. Shear stress enhanced the radiation toxicity to colon cancer cells through suppression of integrin signaling and protein degradation of FAK. The results of our study provide a strong rationale for cancer treatment that combines between radiation and strategy in modulating tumor interstitial fluid flow.

Destabilization of KLF10, a tumor suppressor, relies on thr93 phosphorylation and isomerase association

KLF10 is now classified as a member of the Krüppel-like transcription factor family and acts as a tumor suppressor. Although KLF10 is originally named as TGF-β-inducible early gene-1 and mimicking the anti-proliferative effect of TGF-β in various carcinoma cells, the transcriptional upregulatory function of KLF10 has been described for a variety of cytokines and in many diseases. Through in vivo and in vitro phosphorylation assays, we identified that KLF10 is a phosphorylated protein in cells. Using yeast-two hybrid screening and site direct mutagenesis, we also identified PIN1 as a novel KLF10 associated protein. PIN1 is a peptidyl-prolyl isomerase enzyme belonging to the parvulin family, which specifically recognizes phosphorylated Ser/Thr-Pro containing substrates. Through protein-protein interaction assays, we showed that the Pro-directed Ser/Thr-Pro motif at Thr-93 in the KLF10 N-terminal region is essential for the interaction between KLF10 and PIN1. More importantly, PIN1 interacts with KLF10 in a phosphorylation-dependent manner and this interaction promotes KLF10 protein degradation in cells. Therefore, KLF10 shows shorter protein stability compared with mutant KLF10 that lacks PIN1 binding ability after cycloheximide treatments. The reversely correlated expression profile between KLF10 and PIN1 as observed in cell lines was also shown in clinic pancreatic cancer specimen. Using in vitro kinase assays and depletion assays, we were able to show that RAF-1 phosphorylates the Thr-93 of KLF10 and affects the KLF10 expression level in cells. Thus these findings as a whole indicate that RAF-1 phosphorylation and PIN1 isomerization together regulate KLF10 stability and further affect the role of KLF10 in tumor progression.

Phase II study of concomitant thalidomide during radiotherapy for hepatocellular carcinoma

PURPOSE

Thalidomide has been demonstrated to possess antitumor activity in patients with advanced hepatocellular carcinoma (HCC). The objective of the present study was to determine whether the combined treatment of thalidomide with radiotherapy (RT) is associated with acceptable toxicity and an improved clinical outcome in HCC patients.

METHODS AND MATERIALS

A total of 24 patients were enrolled to receive RT combined with thalidomide. A total dose of 50 Gy was delivered in 2-Gy fractions within 5 weeks. Thalidomide was administered 100 mg twice daily starting 3 days before RT until the development of unacceptable toxicity or disease progression. Blood samples were collected before, during, and after treatment to measure the levels of angiogenic factors and cytokines. The results of patients receiving the combined therapy were compared with those from 18 HCC patients receiving RT only.

RESULTS

No significant difference in the clinical parameters was noted between the two groups, except for the baseline interleukin-6 level, which was greater in the concomitant group (p = .05). The most common toxicities related to thalidomide use were skin rash (54.2%), somnolence (37.5%), and constipation (33.3%). No significant differences were seen in the response rate (55.6% vs. 58.3%, p = .48), median progression-free survival (182 ± 48.9 vs. 148 ± 6.2 days, p = .15), or median overall survival (258 ± 45.6 vs. 241 ± 38.6, p = .16) between those who received concomitant therapy and those who received RT alone. Thalidomide suppressed the serum basic fibroblast growth factor level significantly during RT (p = .03) and, to a lesser extent, the interleukin-6 and tumor necrosis factor-α levels. After adjusting for other potential prognostic factors in the multivariate analysis, only the baseline interleukin-6 level and stem cell-derived factor-1 during RT independently predicted the progression-free survival. A decreased serum stem cell-derived factor-1 level 1 month after RT completion was a significant predictor of the overall survival of HCC patients receiving RT.

CONCLUSIONS

Despite the acceptable toxicity, thalidomide provided no additional benefit for HCC patients undergoing RT.

Dynamic MRI signals in the second week of radiotherapy relate to treatment outcomes of hepatocellular carcinoma: a preliminary result

AIM

Radiotherapy (RT) has been used to treat hepatocellular carcinoma (HCC) in recent years. Despite its good local control, slow tumoral shrinkage and rapid recurrence compromise treatment outcomes. We evaluated the signal intensity of the hepatic parenchyma and tumours by using dynamic contrast enhanced magnetic resonance imaging (MRI) and correlated the findings with clinical outcomes. Nineteen patients with advanced HCC received 50 Gy in 25 fractions. They underwent a dynamic contrast-enhanced, turbo fast low-angle shot MR sequence at 1.5 T before therapy, at 2 weeks of therapy, and 1 month (week 9) later. Initial first-pass enhancement slopes (slope) and peak enhancement ratios (peak) were measured.

RESULTS

Initial signal intensities were not associated with RT outcomes. An increased slope and peak of the tumour at week 2 was associated with an improved local response (P<0.05). In the parenchyma, an increased slope at week 2 was associated with recurrence outside the radiation fields or with progression over distant sites (P<0.05). The differences in signal changes at week 2 during RT were not persistent at a statistically significant level at 1 month after RT.

CONCLUSION

Dynamic contrast-enhanced MRI signals may act as biomarkers for early prediction of responses to RT in patients with HCC. Signal intensities at week 2 are important in evaluating treatment outcomes.

Phase I study of biweekly gemcitabine followed by oxaliplatin and simplified 48-h infusion of fluorouracil/leucovorin for advanced pancreatic cancer

OBJECTIVES

To evaluate the feasibility and maximal tolerated dose (MTD) of oxaliplatin of a triplet regimen consisting of gemcitabine, oxaliplatin and infusional fluorouracil (5-FU)/leucovorin (LV) (GOFL) for advanced pancreatic cancer.

PATIENTS AND METHODS

Patients with histologically proven metastatic or unresectable, locally advanced pancreatic adenocarcinoma were eligible to take part in the study. The treatment consisted of fixed-rate infusion (10 mg/m2/minute) of 800 mg/m2 gemcitabine followed by 2-h infusion of oxaliplatin and then 48-h infusion of 5-FU/LV day 1 and day 15 every 4 weeks. The oxaliplatin would be evaluated at three dose levels, 65, 75 and 85 mg/m2.

RESULTS

A total of 15 patients were enrolled at three dose levels. Dose-limiting toxicity of neutropenic fever and grade 4 thrombocytopenia occurred in one of each six patients at oxaliplatin dose level of 65 mg/m2 and 85 mg/m2, respectively. The MTD of oxaliplatin for this combination was 85 mg/m2. After a median four cycles of treatment, grade 3/4 neutropenia occurred in 46.7% of patients and thrombocytopenia in 13.3%. Non-hematological toxicities were generally of grade 1/2. Objective tumor response was observed in five patients (33.3%, 95% confidence interval, 6.3-60.4%).

CONCLUSION

Biweekly GOFL is a feasible regimen for advanced pancreatic cancer. For further phase II studies, the recommended dose of oxaliplatin is 85 mg/m2.

ATM regulates target switching to escalating doses of radiation in the intestines

Although stem cells succumbing to reproductive death are assumed to be the single relevant targets in radiation tissue damage, recent studies showed intestinal stem cell damage is conditionally linked to crypt endothelial apoptosis, defining a two-target model. Here we report that when mouse intestines were protected against microvascular apoptosis, radiation switched as the dose escalated to a previously unrecognized crypt stem cell target, activating ceramide synthase-mediated apoptosis to initiate intestinal damage. Whereas ataxia telangiectasia-mutated (ATM) kinase normally represses ceramide synthase, its derepression in Atm(-/-) mice increased crypt stem cell radiosensitivity 3.7-fold without sensitizing the microvascular response. Discovery of this intestinal radiosensitivity mechanism allowed design of an antisense Atm oligonucleotide treatment which phenocopied the Atm(-/-) mouse, reordering ceramide synthase-mediated stem cell death to become the first-line gastrointestinal response of wild-type littermates. These experiments indicate that tissues operate multiple potential targets activated consecutively according to their inherent radiosensitivities that may be reordered therapeutically to control radiation tissue responses.

Preoperative concurrent chemotherapy and radiotherapy in rectal cancer patients

The management of rectal cancer has changed significantly in recent years. The key end-point is no longer survival but rather preservation of sphincter function with improved quality of life. Preoperative radiation can not only render a low-lying rectal tumor amenable to sphincter-preserving surgery but has also been reported to give better local control and lower toxicity than postoperative radiotherapy. From October 1991 through July 1996, 46 patients with local advanced or low-lying rectal cancer were treated with preoperative high-dose radiotherapy and concurrent chemotherapy. All patients underwent pelvic radiotherapy with 5,000 to 5,400 cGy in 25 to 27 fractions. Chemotherapy was given concomitantly and consisted of two courses of 5-fluorouracil (5-FU) at 1,000 mg/m2 for 4 days in week 1 and week 5 plus mitomycin C 10 mg/m2 single bolus on day 1 of week 1. In 30 patients, postoperative adjuvant chemotherapy with 5-FU and levamisole weekly was also given, for a total of 12 months. The most common acute toxicity was grade 1 to 2 diarrhea and tenesmus during radiation or soon afterward. Only five of the 46 patients experienced symptomatic grade 3 acute toxicity. Forty-two patients underwent subsequent surgery 6 to 8 weeks after concurrent chemoradiotherapy. Pathologic examination disclosed complete tumor regression in eight patients and microscopic residual disease in 13 patients after preoperative chemoradiation. Of the 42 patients who completed the intended treatments, only one had local recurrence. The sphincter was preserved in 21 of the 26 patients in whom the tumor was located within 5 cm above the anal verge. Twelve of the 16 evaluable patients had good to excellent sphincter function. The 2-year overall survival rate was 93% and the disease-free survival was 81%. Our findings indicate that preoperative concurrent chemoradiotherapy not only allows low-lying rectal tumors to be resected while preserving sphincter function but also results in good local control and acceptable toxicity.

Angioimmunoblastic lymphadenopathy with dysproteinemia--lack of a prognostic value of clear cell morphology

It has been suggested that angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) is closely related to peripheral T cell lymphoma (PTCL). However, the clinical course of AILD-like PTCL is notoriously unpredictable. A minor portion of patients enjoyed prolonged remission with steroid-only treatments (indolent AILD) while most others died rapidly despite the use of intensive chemotherapy (aggressive AILD). Recently, it has been suggested that histological features such as the presence or absence of clear cells and convoluted cells are of high prognostic value. The validity of this observation was addressed in this study. Eighteen patients who presented between 1977 and 1994 at the National Taiwan University Hospital were retrospectively studied. There were 11 men and 7 women, with a median age of 47 years. Twelve patients had received various regimens of systemic chemotherapy, and the other 3 patients had been treated with steroids alone. Eight patients had indolent AILD and 6 aggressive AILD. The follow-up period in 4 patients was too short to be analyzed. The histopathology of these cases was divided, according to the criteria of Aozasa et al., into group I (neither cells), 4 patients; group II (only convoluted cells), 1 patient, and group III (clear cells with or without convoluted cells), 13 patients. Contrary to others, our data revealed that group III patients were doing better than group I patients. Univariate analysis of other pertinent clinical features, including sex, age, lymphadenopathy, B symptoms, hepatosplenomegaly, hypergammaglobulinemia, elevated serum lactate dehydrogenase, and treatment regimens, revealed none of them to be prognostically relevant. However, patients who had achieved complete remission by steroids or other systemic chemotherapy had a significantly better prognosis than those who had not. Together, these preliminary data suggested that (1) the presence or absence of clear cells and convoluted cells failed to predict the clinical behavior, and (2) induction of complete remission by steroids or other chemotherapeutic agents is an important prognostic index.

Comparison of clinical and biologic features between myeloid and lymphoid transformation of Philadelphia chromosome positive chronic myeloid leukemia

Analysis of clinical and biologic features of chronic myeloid leukemia (CML) in blast crisis (BC) was performed on 36 patients: 25 had myeloid and 11 had lymphoid transformation. The median duration from diagnosis to onset of BC was significantly shorter in patients with lymphoid BC (6 months) than in those with myeloid BC (41 months). Patients in lymphoid transformation showed better response to therapy and had a significantly longer median survival time after BC than patients with myeloid transformation (56% vs 0% and 10 months vs 4 months, respectively). The leukemic cells from all the patients with lymphoid BC showed B-cell immunophenotype, confirmed by the presence of immunoglobulin (Ig) heavy chain gene rearrangements in the five patients studied. Two of the eight patients with complete marker study expressed myeloid-associated antigens on the blasts. A high incidence of CD7 expression (7/17 or 41%) was found in patients with myeloid BC, but none of the patients who had DNA analysis showed rearrangement of T-cell receptor beta chain gene. Chromosomal abnormalities +8, +19, +21, and i(17q) were detected only in the patients with myeloid BC but not in those with lymphoid BC. Combined analysis of the patients in this series and those reported previously has revealed a statistically significant difference in the distribution of bcr breakpoints between myeloid and lymphoid BC: the bcr breakpoints in more than half of the patients with myeloid crisis were mapped to Zone 2 while those in patients with lymphoid crisis occurred most frequently in Zone 3.