Treatment planning for MR-guided SBRT of pancreatic tumors on a 1.5 T MR-Linac: A global consensus protocol.

Background and purpose: Treatment planning for MR-guided stereotactic body radiotherapy (SBRT) for pancreatic tumors can be challenging, leading to a wide variation of protocols and practices. This study aimed to harmonize treatment planning by developing a consensus planning protocol for MR-guided pancreas SBRT on a 1.5 T MR-Linac. Materials and methods: A consortium was founded of thirteen centers that treat pancreatic tumors on a 1.5 T MR-Linac. A phased planning exercise was conducted in which centers iteratively created treatment plans for two cases of pancreatic cancer. Each phase was followed by a meeting where the instructions for the next phase were determined. After three phases, a consensus protocol was reached. Results: In the benchmarking phase (phase I), substantial variation between the SBRT protocols became apparent (for example, the gross tumor volume (GTV) D99% ranged between 36.8 - 53.7 Gy for case 1, 22.6 - 35.5 Gy for case 2). The next phase involved planning according to the same basic dosimetric objectives, constraints, and planning margins (phase II), which led to a large degree of harmonization (GTV D99% range: 47.9-53.6 Gy for case 1, 33.9-36.6 Gy for case 2). In phase III, the final consensus protocol was formulated in a treatment planning system template and again used for treatment planning. This not only resulted in further dosimetric harmonization (GTV D99% range: 48.2-50.9 Gy for case 1, 33.5-36.0 Gy for case 2) but also in less variation of estimated treatment delivery times. Conclusion: A global consensus protocol has been developed for treatment planning for MR-guided pancreatic SBRT on a 1.5 T MR-Linac. Aside from harmonizing the large variation in the current clinical practice, this protocol can provide a starting point for centers that are planning to treat pancreatic tumors on MR-Linac systems.

Local Control Following Stereotactic Body Radiation Therapy for Liver Oligometastases: Lessons from a Quarter Century.

The utilization of stereotactic body radiation therapy for the treatment of liver metastasis has been widely studied and has demonstrated favorable local control outcomes. However, several predictive factors play a crucial role in the efficacy of stereotactic body radiation therapy, such as the number and size (volume) of metastatic liver lesions, the primary tumor site (histology), molecular biomarkers (e.g., KRAS and TP53 mutation), the use of systemic therapy prior to SBRT, the radiation dose, and the use of advanced technology and organ motion management during SBRT. These prognostic factors need to be considered when clinical trials are designed to evaluate the efficacy of SBRT for liver metastases.

Inflammatory Cytokines and Radiotherapy in Pancreatic Ductal Adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) remains a therapeutic challenge in clinical oncology. Surgery is the only potentially curative treatment. However, the majority of PDAC patients present with locally advanced/unresectable or metastatic disease, where palliative multiagent chemotherapy is the first-line treatment with the therapeutic intent to delay progression and prolong survival. For locally advanced/unresectable pancreatic cancer patients who are treated with chemotherapy, consolidative radiotherapy in the form concurrent chemoradiation or stereotactic ablative radiotherapy improves locoregional control and pain/symptom control. To improve clinical outcomes of PDAC patients, there is a dire need for discoveries that will shed more light on the pathophysiology of the disease and lead to the development of more efficacious treatment strategies. Inflammatory cytokines are known to play a role in mediating tumor progression, chemoresistance, and radioresistance in PDAC. A PubMed search on published articles related to radiotherapy, inflammatory cytokines, and pancreatic cancer patients in the English language was performed. This article primarily focuses on reviewing the clinical literature that examines the association of inflammatory cytokines with clinical outcomes and the effects of radiotherapy on inflammatory cytokines in PDAC patients.

Sensitivity Training for Mothers With Premature Infants: A Randomized Controlled Trial.

OBJECTIVE: This single-blind parallel design randomized controlled trial evaluated the feasibility and effectiveness of a modified version of the Mother-Infant Transaction Program (MITP) in enhancing Chinese mothers' sensitivity towards their premature infants' physiological and social cues. METHODS: Sixty mothers of hospitalized premature infants (mean gestational age = 32.1 weeks; SD = 2.8) were randomly assigned to either the MITP group or the treatment-as-usual control group. The intervention group (n = 30) received four sessions of parental sensitivity training adapted from the MITP, delivered by clinical psychologists before the infants were discharged. The control group (n = 30) received standard care provided by the hospitals. Each dyad was assessed at baseline (Time 1), immediately after intervention (Time 2), and when the infants were at the gestation-corrected ages of 3, 6, 9, and 12 months (Times 3-6). Maternal sensitivity, mother-infant interaction quality, parenting stress, postpartum depression, and mother's perception of infant's temperament were measured at Times 1-4, whereas infants' weight gain and developmental performance were assessed at Times 3-6. RESULTS: The MITP group showed significantly higher maternal sensitivity and better mother-infant interaction quality after completing the training. They also reported less parenting stress and postnatal depression than the control group at Time 2 and subsequent follow-ups. The intervention significantly predicted better weight gain and developmental outcomes in infants across Times 3-6, mediated by maternal wellbeing and interaction quality. CONCLUSION: Our results demonstrated the feasibility and effectiveness of this adapted sensitivity training among Chinese mothers with premature infants. [ClinicalTrials.gov NCT04383340].

Benchmarking Outcomes after Ablative Radiotherapy for Molecularly Characterized Intrahepatic Cholangiocarcinoma.

We have previously shown that ablative radiotherapy (A-RT) with a biologically effective dose (BED10) ≥ 80.5 Gy for patients with unresectable intrahepatic cholangiocarcinoma (ICC) is associated with longer survival. Despite recent large-scale sequencing efforts in ICC, outcomes following RT based on genetic alterations have not been described. We reviewed records of 156 consecutive patients treated with A-RT for unresectable ICC from 2008 to 2020. For 114 patients (73%), next-generation sequencing provided molecular profiles. The overall survival (OS), local control (LC), and distant metastasis-free survival (DMFS) were estimated using the Kaplan-Meier method. Univariate and multivariable Cox analyses were used to determine the associations with the outcomes. The median tumor size was 7.3 (range: 2.2-18.2) cm. The portal vein thrombus (PVT) was present in 10%. The RT median BED10 was 98 Gy (range: 81-144 Gy). The median (95% confidence interval) follow-up was 58 (42-104) months from diagnosis and 39 (33-74) months from RT. The median OS was 32 (29-35) months after diagnosis and 20 (16-24) months after RT. The one-year OS, LC, and intrahepatic DMFS were 73% (65-80%), 81% (73-87%), and 34% (26-42%). The most common mutations were in IDH1 (25%), TP53 (22%), ARID1A (19%), and FGFR2 (13%). Upon multivariable analysis, the factors associated with death included worse performance status, larger tumor, metastatic disease, higher CA 19-9, PVT, satellitosis, and IDH1 and PIK3CA mutations. TP53 mutation was associated with local failure. Further investigation into the prognostic value of individual mutations and combinations thereof is warranted.

Dosimetric Uncertainties Resulting From Interfractional Anatomic Variations for Patients Receiving Pancreas Stereotactic Body Radiation Therapy and Cone Beam Computed Tomography Image Guidance.

PURPOSE: To estimate the effects of interfractional anatomic changes on dose to organs at risk (OARs) and tumors, as measured with cone beam computed tomography (CBCT) image guidance for pancreatic stereotactic body radiation therapy. METHODS AND MATERIALS: We evaluated 11 patients with pancreatic cancer whom were treated with stereotactic body radiation therapy (33-40 Gy in 5 fractions) using daily CT-on-rails (CTOR) image guidance immediately before treatment with breath-hold motion management. CBCT alignment was simulated in the treatment planning software by aligning the original planning CT to each fractional CTOR image set via fiducial markers. CTOR data sets were used to calculate fractional doses after alignment by applying the rigid shift of the planning CT and CTOR image sets to the planning treatment isocenter and recalculating the fractional dose. Accumulated dose to the gross tumor volume (GTV), tumor vessel interface, duodenum, small bowel, and stomach were calculated by summing the 5 fractional absolute dose-volume histograms into a single dose-volume histogram for comparison with the original planned dose. RESULTS: Four patients had a GTV D100% of at least 1.5 Gy less than the fractional planned value in several fractions; 4 patients had fractional underestimation of duodenum dose by 1.0 Gy per fraction. The D1.0 cm3 <35 Gy constraint was violated for at least 1 OAR in 3 patients, with either the duodenum (n = 2) or small bowel (n = 1) D1.0 cm3 being higher on the accumulated dose distribution (P = .01). D100% was significantly lower according to accumulated dose GTV (P = .01) and tumor vessel interface (P = .02), with 4 and 2 patients having accumulated D100%  ≥4 Gy lower than the planned value for the GTV and tumor vessel interface, respectively. CONCLUSIONS: For some patients, CBCT image guidance based on fiducial alignment may cause large dosimetric uncertainties for OARs and target structures, according to accumulated dose.

Plasma metabolomic profiles in liver cancer patients following stereotactic body radiotherapy.

BACKGROUND: Stereotactic body radiotherapy (SBRT) is an effective treatment for hepatocellular carcinoma (HCC). This study sought to identify differentially expressed plasma metabolites in HCC patients at baseline and early during SBRT, and to explore if changes in these metabolites early during SBRT may serve as biomarkers for radiation-induced liver injury and/or tumour response. METHODS: Forty-seven HCC patients were treated with SBRT on previously published prospective trials. Plasma samples were collected at baseline and after one to two fractions of SBRT, and analysed by GC/MS and LC/MS for untargeted and targeted metabolomics profiling, respectively. FINDINGS: Sixty-nine metabolites at baseline and 62 metabolites after one to two fractions of SBRT were differentially expressed, and strongly separated the Child Pugh (CP) B from the CP A HCC patients. These metabolites are associated with oxidative stress and alterations in hepatic cellular metabolism. Differential upregulation of serine, alanine, taurine, and lipid metabolites early during SBRT from baseline was noted in the HCC patients who demonstrated the greatest increase in CP scores at three months post SBRT, suggesting that high protein and lipid turnover early during SBRT may portend increased clinical liver toxicity. Twenty annotated metabolites including fatty acids, glycerophospholipids, and acylcarnitines were differentially upregulated early during SBRT from baseline and separated patients with complete/partial response from those with stable disease at three months post SBRT. INTERPRETATION: Dysregulation of amino acid and lipid metabolism detected early during SBRT are associated with subsequent clinical liver injury and tumour response in HCC.

Single-Fraction Stereotactic Body Radiation Therapy: A Paradigm During the Coronavirus Disease 2019 (COVID-19) Pandemic and Beyond?

PURPOSE: Owing to the coronavirus disease 2019 (COVID-19) pandemic, radiation oncology departments have adopted various strategies to deliver radiation therapy safely and efficiently while minimizing the risk of severe acute respiratory syndrome coronavirus-2 transmission among patients and health care providers. One practical strategy is to deliver stereotactic body radiation therapy (SBRT) in a single fraction, which has been well established for treating bone metastases, although it has been infrequently used for other extracranial sites. METHODS AND MATERIALS: A PubMed search of published articles in English related to single-fraction SBRT was performed. A critical review was performed of the articles that described clinical outcomes of single-fraction SBRT for treatment of primary extracranial cancers and oligometastatic extraspinal disease. RESULTS: Single-fraction SBRT for peripheral early-stage non-small cell lung cancer is supported by randomized data and is strongly endorsed during the COVID-19 pandemic by the European Society for Radiotherapy and Oncology-American Society for Radiation Oncology practice guidelines. Prospective and retrospective studies supporting a single-fraction regimen are limited, although outcomes are promising for renal cell carcinoma, liver metastases, and adrenal metastases. Data are immature for primary prostate cancer and demonstrate excess late toxicity in primary pancreatic cancer. CONCLUSIONS: Single-fraction SBRT should be strongly considered for peripheral early-stage non-small cell lung cancer during the COVID-19 pandemic to mitigate the potentially severe consequences of severe acute respiratory syndrome coronavirus-2 transmission. Although single-fraction SBRT is promising for the definitive treatment of other primary or oligometastatic cancers, multi-fraction SBRT should be the preferred regimen owing to the need for additional prospective evaluation to determine long-term efficacy and safety.

Association of pro-inflammatory soluble cytokine receptors early during hepatocellular carcinoma stereotactic radiotherapy with liver toxicity.

Plasma levels of soluble factors early during hepatocellular carcinoma (HCC) stereotactic body radiotherapy (SBRT) were evaluated in relation to radiation liver injury, tumor response, and risk of early death. No significant differences were found in baseline plasma levels of AFP, CXCL1, and HGF amongst HCC patients with different Child Pugh scores. Higher levels of sTNFRII (P < 0.001), and lower levels of sCD40L (P < 0.001) and CXCL1 (P = 0.01) following one to two fractions of SBRT were noted in patients who developed liver toxicity vs. those who did not. High circulating levels of AFP (HR 2.16, P = 0.04), sTNFRII (HR 2.27, P = 0.01), and sIL-6R (HR 1.99, P = 0.03) early during SBRT were associated with increased risk of death 3 months post treatment. Plasma levels of the studied factors early during SBRT were not associated with tumor response. A pro-inflammatory systemic environment is associated with development of liver toxicity and increased risk of early death following SBRT.

Population estimates of Bornean orang-utans using Bayesian analysis at the greater Batang Ai-Lanjak-Entimau landscape in Sarawak, Malaysia.

The integration of Bayesian analysis into existing great ape survey methods could be used to generate precise and reliable population estimates of Bornean orang-utans. We used the Marked Nest Count (MNC) method to count new orang-utan nests at seven previously undocumented study sites in Sarawak, Malaysia. Our survey teams marked new nests on the first survey and revisited the plots on two more occasions; after about 21 and 42 days respectively. We used the N-mixture models to integrate suitability, abundance and detection models which account for zero inflation and imperfect detection for the analysis. The result was a combined estimate of 355 orang-utans with the 95% highest density interval (HDI) of 135 to 602 individuals. We visually inspected the posterior distributions of our parameters and compared precisions between study sites. We subsequently assess the strength or reliability of the generated estimates using identifiability tests. Only three out of the seven estimates had <35% overlap to indicate strong reliability. We discussed the limitations and advantages of our study design, and made recommendations to improve the sampling scheme. Over the course of this research, two of the study sites were gazetted as extensions to the Lanjak-Entimau Wildlife Sanctuary for orang-utan conservation.

Local control in young women with early-stage breast cancer treated with hypofractionated whole breast irradiation.

OBJECTIVE: To compare local control (LC) in young women with early-stage breast cancer (BC) treated with hypofractionated (HF) whole breast irradiation (WBI) vs conventional fractionation (CF) following breast-conserving surgery (BCS). MATERIALS AND METHODS: Women <50 years with pT1-2N0 BC following BCS treated with WBI, CF (50Gy/25 fractions) or HF (42.4Gy/16 fractions) followed by a tumor bed boost (10-16Gy/5-8 fractions) from 2009 to 2013 were identified from an institutional database. Median follow-up was 5.2 years (range 0.3-8.4). Kaplan-Meier analysis was used to estimate 5-year LC. Logistic regression identified factors associated with receipt of CF vs HF WBI. RESULTS: Of 270 eligible women, 227 (84%) were treated with HF and 43 (16%) with CF WBI. A tumor bed boost of 10 Gy/5 fractions was given in 97% of patients, 53% received adjuvant chemotherapy and 94% (225/239) with estrogen-positive disease received endocrine therapy. Median age was 45 years (range 30-49) in HF and 40 years (range 19-49) in the CF group. The 5-year LC rate was 99.3% (95% CI 97.9-100%, p = 0.495) in the HF and 97.5% (95% CI 92.8-100%) in the CF group. On univariate analysis, age ≤ 40 years or triple negative BC was associated with a decreased likelihood of receiving HF WBI. Only age remained significant on multivariate analysis [OR 2.82 (95% CI 1.45-5.48, p = 0.002)]. CONCLUSIONS: HF WBI was associated with excellent LC rates in this study cohort, comparable to CF WBI. However, CF WBI was more likely to be recommended to women <40 years.

Radiation-Induced Liver Toxicity.

The advent of highly conformal radiation therapy (RT) has defined a new role for RT in the treatment of both primary and metastatic liver cancer. Despite major advances in how RT is delivered, radiation-induced liver disease (RILD) remains a concern. Classic RILD, characterized by anicteric ascites and hepatomegaly, is unlikely to occur if treating to doses of ≤30Gy in 2Gy per fraction in patients with baseline Child-Pugh A liver function. On the other hand, nonclassic RILD is a spectrum of liver toxicity, including a general decline in liver function and elevation of liver enzymes. It is less well defined and less predictable, especially in patients with underlying liver disease. Scoring and quantifying RILD remains a challenge. The Child-Pugh score has been the most consistently used parameter. Other scoring systems such as the albumin-bilirubin score provide further discrimination in patients with hepatocellular carcinoma, although their value in patients treated with RT remains to be established. Many serum and imaging biomarkers of liver function are currently being investigated, and they will provide further useful information in the future for local and global liver function assessment, for planning optimization, and for treatment adaptation. To date, no pharmacological therapies have provided consistent results in mitigating RILD once it has manifested clinically. Numerous promising treatment strategies including TGFß inhibition, Hedgehog inhibition, CXCR4 inhibition, hepatocyte transplantation, and bone marrow-derived stromal cell therapy, have potential to be helpful in the treatment of RILD in the future.

Use of remote blood releasing system for red cell transfusion in hospice care center.

OBJECTIVES: It is quite common to have advanced cancer or end-stage renal disease patients for regular or even frequent blood transfusion in palliative care. However, due to geographical reason in some hospice centers, blood transfusion is sometimes difficult if blood bank is closed during non-office hour or not available. METHODS: Here, we reported a new blood releasing system, that is, remote blood releasing system, that could be used safely by nursing staff alone when the blood bank was closed during the night time and holiday. RESULTS: On-call nursing staff could collect red cells successful in these two cases. CONCLUSION: The new blood releasing system seems useful. However, larger sample sizes and longer period of study are required to estimate its efficacy and safety. The provision of antibody-positive red cells and platelet remained a limitation of this system.

The differential effects of metronomic gemcitabine and antiangiogenic treatment in patient-derived xenografts of pancreatic cancer: treatment effects on metabolism, vascular function, cell proliferation, and tumor growth.

BACKGROUND: Metronomic chemotherapy has shown promising activity against solid tumors and is believed to act in an antiangiogenic manner. The current study describes and quantifies the therapeutic efficacy, and mode of activity, of metronomic gemcitabine and a dedicated antiangiogenic agent (DC101) in patient-derived xenografts of pancreatic cancer. METHODS: Two primary human pancreatic cancer xenograft lines were dosed metronomically with gemcitabine or DC101 weekly. Changes in tumor growth, vascular function, and metabolism over time were measured with magnetic resonance imaging, positron emission tomography, and immunofluorescence microscopy to determine the anti-tumor effects of the respective treatments. RESULTS: Tumors treated with metronomic gemcitabine were 10-fold smaller than those in the control and DC101 groups. Metronomic gemcitabine, but not DC101, reduced the tumors' avidity for glucose, proliferation, and apoptosis. Metronomic gemcitabine-treated tumors had higher perfusion rates and uniformly distributed blood flow within the tumor, whereas perfusion rates in DC101-treated tumors were lower and confined to the periphery. DC101 treatment reduced the tumor's vascular density, but did not change their function. In contrast, metronomic gemcitabine increased vessel density, improved tumor perfusion transiently, and decreased hypoxia. CONCLUSION: The aggregate data suggest that metronomic gemcitabine treatment affects both tumor vasculature and tumor cells continuously, and the overall effect is to significantly slow tumor growth. The observed increase in tumor perfusion induced by metronomic gemcitabine may be used as a therapeutic window for the administration of a second drug or radiation therapy. Non-invasive imaging could be used to detect early changes in tumor physiology before reductions in tumor volume were evident.

Phase 1 Trial of Sorafenib and Stereotactic Body Radiation Therapy for Hepatocellular Carcinoma.

PURPOSE: To determine the maximally tolerated dose of sorafenib delivered before, during, and after stereotactic body radiation therapy (SBRT) in hepatocellular carinoma (HCC). METHODS AND MATERIALS: Eligible patients had locally advanced Child-Pugh class A HCC, showed Eastern Cooperative Oncology Group performance status 0-1, and were ineligible for standard local-regional therapies. Sorafenib was dose escalated in 2 strata: (1) low effective irradiated liver volume (veff) < 30% and (2) high veff 30%to 60%. Sorafenib (400 mg daily = dose level 1) was administered for 12 weeks, with 6 fractions SBRT delivered weeks 2 and 3, and escalation to full dose (400 mg twice daily) after 12 weeks as tolerated. Standard 3 + 3 cohorts with dose escalation of sorafenib were planned. RESULTS: Sixteen patients (4 low veff, median dose 51 Gy; 12 high veff, median dose 33 Gy) were treated at 2 sorafenib dose levels. Of those patients 75% were had Barcelona Clinic Liver Cancer stage C, and 63% had main branch portal vein invasion. In the low veff stratum, no dose-limiting toxicities (DLTs) were observed in 4 patients treated with SBRT and sorafenib 400 mg. Inb the high veff stratum: 2 of 3 evaluable patients treated with sorafenib 400 mg experienced DLT (grade 3 large bowel bleed and grade 4 bowel obstruction 51 and 27 days, respectively, after SBRT). One of 6 evaluable patients at dose level -1 (200 mg once daily) experienced a grade 3 tumor rupture at week 5. Median overall survival and in-field local progression have not been reached. Worsening of Child-Pugh liver function class was seen in 6 of 12 patients in the high veff stratum. CONCLUSIONS: Significant toxicity was observed in the high veff stratum, and concurrent SBRT with sorafenib is not recommended outside a clinical trial.

The involvement of insulin-like growth factor 2 binding protein 3 (IMP3) in pancreatic cancer cell migration, invasion, and adhesion.

BACKGROUND: Over-expression of insulin-like growth factor 2 mRNA binding protein 3 (IMP3) is correlated with poor prognosis in pancreatic ductal adenocarcinoma (PDAC). Previous studies examining other cancer types have implicated IMP3 in the regulation of several cellular functions that are characteristic of tumour cells. However, the role of this oncofetal protein in PDAC progression remained unclear. METHODS: Using siRNA, we examined the effect of IMP3 inhibition on the motility, invasive ability, and matrix adhesion of PDAC cells. In addition, we also evaluated the expression of cytoskeleton-associated genes following IMP depletion. RESULTS: Knockdown of IMP3 significantly decreased the motility, invasion, and extracellular matrix adhesion of select PDAC cells in vitro. In addition, IMP3-depleted cells exhibited lower levels of CD44 protein and KIF11 mRNA. Moreover, we also observed a reduction in downstream RhoA signaling following IMP3 knockdown, indicating that IMP3 modulates the levels of proteins involved in cytoskeletal organization. CONCLUSIONS: These results suggest that IMP3 facilitates PDAC progression by enhancing the pro-metastatic behaviour of tumour cells.

Irinophore C™, a lipid nanoparticulate formulation of irinotecan, improves vascular function, increases the delivery of sequentially administered 5-FU in HT-29 tumors, and controls tumor growth in patient derived xenografts of colon cancer.

PURPOSE: A liposomal formulation of irinotecan, Irinophore C™ (IrC™) is efficacious in a panel of tumor models, normalizes tumor vasculature, and increases the accumulation of a second drug in the same tumor. We now show that Irinophore C™ is also effective against patient derived xenografts (PDX) of colon cancer, and examine the kinetics of vascular normalization in the HT-29 tumor model and assess how these changes might be used with 5-FU sequentially. MATERIALS AND METHODS: Rag2M mice bearing HT-29 tumors were treated with IrC™ (25mg/kg; Q7D×3) for up to three weeks. Groups of tumors were harvested for analysis at 7, 14 and 21days after the start of treatment. Drug and lipid levels in the tumor were evaluated using HPLC and scintillation counts, respectively. Changes in tumor morphology (H&E), vasculature (CD31), perfusion (Hoechst 33342) and apoptosis (TUNEL) were quantified using microscopy. The accumulation of a second drug ([(14)C]-5-FU, 40mg/kg) given 3h before sacrifice was determined using liquid scintillation. The efficacy of IrC™ (Q7D×3) followed by 5-FU treatment (Q7D×3) was assessed in mice bearing established HT-29 tumors. The efficacy of IrC™ was also evaluated in primary human colorectal tumors grown orthotopically in NOD-SCID mice. RESULTS: Following a single dose of IrC™ the active lactone forms of irinotecan and its metabolite SN-38 were measurable in HT-29 tumors after 7days. The treatment reduced tumor cell density and increased apoptosis. Hoechst 33342 perfusion and accumulation of [(14)C]-5-FU in the treated tumors increased significantly on days 7 and 14. This was accompanied by an increase in the number of endothelial cells relative to total nuclei in the tumor sections. Pre-treatment with IrC™ (Q7D×3) followed by 5-FU (Q7D×3) delayed the time taken for tumors to reach 1cm(3) by 9days (p<0.05). IrC™ was just as effective as free irinotecan when used on patient derived xenografts of colorectal cancer. CONCLUSIONS: Treatment with IrC™ reduces tumor cell viability and appears to normalize the vascular function of the tumor after a single treatment cycle. A concomitant increase in the accumulation of a second drug (5-FU) in the tumor was observed in tumors from IrC™ treated animals and this was correlated with changes in vascular structure consistent with normalization. The treatment effects of sequential 5-FU dosing following IrC™ are additive with no additional toxicity in contrast to previous studies where concurrent 5-FU and IrC™ treatment exacerbated 5-FU toxicity. The studies with PDX tumors also indicate that IrC™ is just as effective as free irinotecan on PDX tumors even though the delivered dose is halved.

B7-H4 expression in normal and diseased human islet ß cells.

OBJECTIVES: B7-H4 is a negative coregulatory molecule known to be involved in immune response. We study here B7-H4 expression and its possible role in diabetes and cancer development. METHODS: Formalin-fixed, paraffin-processed pancreas samples from patients with type 1 diabetes (T1D), insulinoma, pancreatic ductal adenocarcinoma (PDAC), and normal organ donors were studied by bright-field and multifluorescence immunohistochemistry to examine B7-H4 expression and its colocalization with islet endocrine hormones. Quantitative RT-PCR and Western blot assay were used to examine B7-H4 mRNA and protein expression in the islet and exocrine tissues from normal donors and pancreatic cancer cell lines. RESULTS: B7-H4 protein expression in islet ß cells is decreased in T1D and PDAC, but increased in insulinoma patients when compared to normal controls; the changes in B7-H4 expression are concomitant with insulin expression on the islet ß cells. The insulin/B7-H4 colocalization on the ß cells, expressed in colocalization coefficient Pearson r, is also changed in these islets. CONCLUSIONS: Our observation of altered B7-H4 expression, concomitant with insulin expression, in the pancreatic islets of T1D, PDAC, and insulinoma patients when compared to normal controls suggests that B7-H4 pathway might play an important role in maintenance of ß-cell function, but its exact role remains to be explored.

The autophagy inhibitor verteporfin moderately enhances the antitumor activity of gemcitabine in a pancreatic ductal adenocarcinoma model.

Pancreatic ductal adenocarcinoma (PDAC) is highly resistant to chemotherapy. It has been described as requiring elevated autophagy for growth and inhibiting autophagy has been proposed as a treatment strategy. To date, all preclinical reports and clinical trials investigating pharmacological inhibition of autophagy have used chloroquine or hydroxychloroquine, which interfere with lysosomal function and block autophagy at a late stage. Verteporfin is a newly discovered autophagy inhibitor that blocks autophagy at an early stage by inhibiting autophagosome formation. Here we report that PDAC cell lines show variable sensitivity to verteporfin in vitro, suggesting cell-line specific autophagy dependence. Using image-based and molecular analyses, we show that verteporfin inhibits autophagy stimulated by gemcitabine, the current standard treatment for PDAC. Pharmacokinetic and efficacy studies in a BxPC-3 xenograft mouse model demonstrated that verteporfin accumulated in tumors at autophagy-inhibiting levels and inhibited autophagy in vivo, but did not reduce tumor volume or increase survival as a single agent. In combination with gemcitabine verteporfin moderately reduced tumor growth and enhanced survival compared to gemcitabine alone. While our results do not uphold the premise that autophagy inhibition might be widely effective against PDAC as a single-modality treatment, they do support autophagy inhibition as an approach to sensitize PDAC to gemcitabine.