PLEKHA5 regulates tumor growth in metastatic melanoma

BACKGROUND

PLEKHA5 has previously been identified as a novel molecule implicated in melanoma brain metastasis, a disease that continues to portend a poor prognosis. The aim of this study was to further investigate the functional role of PLEKHA5 in disseminated melanoma.

METHODS

The impact of PLEKHA5 on proliferation and tumor growth was examined in vitro and in melanoma xenograft models, including brain-tropic melanomas (melanomas tending to disseminate to the brain). In vitro loss- and gain-of-function studies were used to explore the underlying mechanisms of PLEKHA5-mediated tumor growth and the crosstalk between PLEKHA5 and PI3K/AKT/mTOR or MAPK/ERK signaling. The clinical relevance of PLEKHA5 dysregulation was further investigated in a cohort of matched cranial and extracranial melanoma metastases.

RESULTS

PLEKHA5 stable knockdown negatively regulated cell proliferation by inhibiting the G₁ -to-S cell cycle transition, which coincided with upregulation of the cell cycle regulator PDCD4. Conversely, ectopic PLEKHA5 expression exhibited the inverse effect. PLEKHA5 knockdown significantly inhibited tumor growth, whereas its overexpression upregulated the growth of tumors, which was induced by cranial and subcutaneous inoculation of cells in nude mice. PLEKHA5 modulation affected PDCD4 protein stability and was coupled with changes in PI3K/AKT/mTOR pathway signaling. High PDCD4 expression in cerebral specimens was associated with better overall survival.

CONCLUSIONS

This study further supports the role of PLEKHA5 as a regulator of melanoma growth at distant sites, including the brain. Furthermore, the results highlight the significance of PDCD4 dysregulation in disseminated melanoma and implicate PDCD4 as a possible causal link between PLEKHA5 and cell proliferation and growth.

RBTT-07. A PHASE 2 TRIAL OF PEMBROLIZUMAB AND BEVACIZUMAB IN MELANOMA BRAIN MET PATIENTS

BACKGROUND

Pembro monotherapy (NCT02085070) produces responses in 26% of (mel) BrM pts. VEGF inhibitors (VEGFi) enhance anti-PD-1 activity in preclinicals. Therefore, we initiated a phase 2 study (NCT02681549) of pembro plus bev in BrM pts.

METHODS

Eligibility includes advanced mel, > 1 asymptomatic BrM, diameter 5-20mm, no steroids, no prior PD-1/PD-L1 or VEGFi. Pembro IV 200mg q3 wks for < yrs with bev 7.5mg/kg for the first 4 cycles. Primary endpoint was BrM RR by modified RECIST.

RESULTS

Between 8/2016 - 1/2019, 20 mel pts were enrolled. 60% were male mdn age 62;ECOG PS was 0 in 16 and 1 in 4 pts; LDH > ULN in 20%; 4 (20%); 10 were BRAFmt; 8 pts (40%) had > 4 untreated BrM. 12 had a BrM response (7 CR, 5 PR); 1 each with SD, unevaluable and an unconfirmed PR, for an ORR BrM of 60% (12/20). All responses lasted 7+ to 30+ mths. 16 pts are alive. AEs attributable to bev include hypertension, microscopic diverticular perforation and wound dehiscence (1 pt each, all resolved). 1 had mucositis attributed to Pembro. Three d/c’d treatment for grade 3 ALT elevation. Cerebral edema decreased in all pts with baseline edema.

CONCLUSIONS

Pembro plus bev demonstrates promising activity in melanoma BrMs compared to pembro alone. The pre-specified primary endpoint (> 4 BrM responses/20) was met, supporting further study. The toxicity profile was similar to pembro alone.

P1217Zirconium-89 labelled probe for molecular imaging of inflammation in experimental atherosclerosis

Background

Early detection of inflamed atherosclerotic lesions by molecular imaging might improve risk assessment beyond that of vascular stenosis and plaque morphology imaging, and improve the clinical management of high-risk patients.

Purpose

To target the key features of unstable atherosclerotic lesions, we studied the feasibility of our radiotracer, based on modified human serum albumin (HSA), to identify inflamed atherosclerotic lesions by in vivo molecular imaging.

Methods

We applied a maleylated HSA (Mal-HSA) probe, recognised by scavenger receptors on macrophages, in an experimental in vivo imaging study of atherosclerosis. Mal-HSA was coupled with a positron-emittingmetal ion, Zirconium-89 (89Zr). The targeting potential of this probe was evaluated and compared with unspecific 89Zr-HSA and 18F-FDG in a mouse model of atherosclerosis (Apoe−/−, n=22) and compared with wild-type (WT) mice (C57BL/6, n=21) as controls. Radiotracer accumulation in the aortic arch was analysed in vivo by the fusion of positron emission tomography–magnetic resonance imaging (PET-MRI), radiotracer bio-distribution was measured ex vivo by gamma counter, and plaque uptake was evaluated by phosphor imaging (PI) autoradiography (ARG).

Results

PET-MRI, gamma counter measurements, and PI-ARG showed the accumulation of 89Zr-Mal-HSA in the atherosclerotic lesions of Apoe−/− mice. The maximum standardised uptake value (SUVmax) for 89Zr-Mal-HSA at 16 and 20 weeks were 26% and 20% higher (P<0.05) in Apoe−/− mice than control WT mice, whereas no difference in SUVmax was found for 18F-FDG in the same animals. 89Zr-Mal-HSA uptake in the aorta as evaluated by gamma counter 48 h post-injection was 32% higher (P<0.01) for Apoe−/− mice compared to WT mice, and the aorta-to-blood ratio was 10-fold higher (P<0.001) for 89Zr-Mal-HSA compared with unspecific 89Zr-HSA. HSA probes were mainly distributed to the liver, spleen, kidneys, bone and lymph nodes. The PI-ARG results corroborated the PET and gamma counter measurements, showing higher accumulation of 89Zr-Mal-HSA in the aortas of Apoe−/− mice compared to WT mice; 9.4±1.4 vs 0.8±0.3% (P<0.001).

Conclusions

The modified HSA-based radiotracer showed in vivo targeting of inflamed atherosclerotic lesions of mouse aorta, which could also be verified ex vivo. 89Zr-Mal-HSA seems to be a promising diagnostic tool for the identification of vascular inflammation. Further methodological studies are needed to verify its applicability for detecting rupture-prone plaques.

Acknowledgement/Funding

Swedish Research Council (22036); the Swedish HLF (20150423, 20170669); ALF (20150517, 447561, 726481); Söderberg Foundations, VINNOVA and KI

Recurrence patterns after resection of retroperitoneal sarcomas: An eight-institution study from the US Sarcoma Collaborative

BACKGROUND AND OBJECTIVES

Resection of primary retroperitoneal sarcomas (RPS) has a high incidence of recurrence. This study aims to identify patterns of recurrence and its impact on overall survival.

METHODS

Adult patients with primary retroperitoneal soft tissue sarcomas who underwent resection in 2000-2016 at eight institutions of the US Sarcoma Collaborative were evaluated.

RESULTS

Four hundred and ninety-eight patients were analyzed, with 56.2% (280 of 498) having recurrences. There were 433 recurrences (1-8) in 280 patients with 126 (25.3%) being locoregional, 82 (16.5%) distant, and 72 (14.5%) both locoregional and distant. Multivariate analyses revealed the following: Patient age P = .0002), tumor grade (P = .02), local recurrence (P = .0003) and distant recurrence (P < .0001) were predictors of disease-specific survival. The 1-, 3-, and 5-year survival rate for patients who recurred vs not was 89.6% (standard error [SE] 1.9) vs 93.5% (1.8), 66.0% (3.2) vs 88.4% (2.6), and 51.8% (3.6) vs 83.9% (3.3), respectively, P < .0001. Median survival was 5.3 years for the recurrence vs 11.3+ years for the no recurrence group (P < .0001). Median survival from the time of recurrence was 2.5 years.

CONCLUSIONS

Recurrence after resection of RPS occurs in more than half of patients independently of resection status or perioperative chemotherapy and is equally distributed between locoregional and distant sites. Recurrence is primarily related to tumor biology and is associated with a significant decrease in overall survival.

[Robot-assisted Whipple resection; results of the first 100 procedures in the Netherlands]

OBJECTIVE

Investigation into the results of robot-assisted Whipple resection in the Netherlands. These results were compared with those of open Whipple procedures on the basis of recent large case series of patients.

DESIGN

Case series of patients and systematic literature review.

METHOD

We carried out a post hoc analysis of prospectively collected data on the first 100 consecutive patients who underwent robot-assisted Whipple procedures in the period from March 2016 until March 2018 at the Erasmus MC, the Maasstad hospital or the Regional Academic Cancer Centre Utrecht. We were mainly interested in surgery characteristics and postoperative outcomes. We compared our results with those of case series of patients with more than 500 open Whipple procedures carried out in a single hospital, published in the last 5 years.

RESULTS

There were one or more serious complications in 22 patients (22%) and 2 patients (2%) developed multiple organ failure. 7 patients (7%) underwent reoperation. There was no postoperative mortality. In 14 case series (n = 12,708), complications occurred in 38% of patients and 7% of patients underwent reoperation. Mean mortality rate was 3%.

CONCLUSION

Our findings show that robotic Whipple procedures can be carried out safely in the Netherlands. The number of complications and mortality rates are comparable with results of large case series of patients who underwent open Whipple procedures in a centre of expertise.

Effects of mass loading on the viability of assessing the state of healing of a fixated fractured long bone

Introduction

This paper aims to evaluate the effects of mass loading on the healing assessment of an internally fixated femur by vibrational means. The presence of soft tissue surrounding a femur increases damping and mass of a system, and hence affects the vibrational response of a mechanical structure by obscuring the coherent modes. This may compromise vibration-based monitoring strategies in identifying modes associated with fracture healing.

Methods

This paper presents a series of experimental works to address this issue. Two osteotomised composite femurs were internally fixated using a plate-screw system and an intramedullary nail. Soft tissue is approximated by surrounding an artificial Sawbone femur with modelling clay. The femur is excited by an instrumented impact hammer and instrumented with two accelerometers to record bending and torsion modes between 0 and 600 Hz. A 30-min epoxy was applied to simulate the healing of the fractured femur in the osteotomised region. The resonant frequencies and its modes are monitored while union is being formed and a healing index is calculated at various times to quantify the degree of healing.

Results

The results demonstrate that the effect of modelling clay compressed the natural modes along the frequency axis. It is observed that frequency bandwidth in the vicinity of 150 Hz and 500 Hz is sensitive to the state of healing of the fixated femurs, which is due to the increase in stiffness of the osteotomised region. These findings were used to formulate the healing index which assists in identifying the initial, later and complete healing stages in conjunction with the index derivative.

Conclusion

In this study, a two-sensor measurement strategy to quantify fixated femur healing is investigated. It is shown that the mass loading effect did not affect this vibrational analysis method ability to assess the state of healing, and both coherent bending and twisting modes associated with healing were easily identified. The proposed healing index, its derivative, and the cross-spectra are a viable tool for quantitative healing assessment.

Mortality risk reduction differs according to bisphosphonate class: a 15-year observational study

In this prospective cohort of 6120 participants aged 50+, nitrogen-bisphosphonates but not non-nitrogen bisphosphonates were associated with a significant 34% mortality risk reduction compared to non-treated propensity score matched controls. These findings open new avenues for research into mechanistic pathways.

INTRODUCTION

Emerging evidence suggests that bisphosphonates (BP), first-line treatment of osteoporosis, are associated with reduced risks for all-cause mortality. This study aimed to determine the association between different BP types and mortality risk in participants with or without a fracture.

METHODS

A prospective cohort study of users of different BPs matched to non-users by propensity score (age, gender, co-morbidities, fragility fracture status) and time to starting the BP medication from the population-based Canadian Multicentre Osteoporosis Study from nine Canadian centres followed from 1995 to 2013. Mortality risk for bisphosphonate users vs matched non-users was assessed using pairwise multivariable Cox proportional hazards models.

RESULTS

There were 2048 women and 308 men on BP and 1970 women and 1794 men who did not receive medication for osteoporosis. The relationship between BP and mortality risk was explored in three separate 1:1 propensity score-matched cohorts of BP users and no treatment (etidronate, n = 599, alendronate, n = 498, and risedronate n = 213). Nitrogen BP (n-BP) (alendronate and risedronate) was associated with lower mortality risks [pairwise HR, 0.66 (95% CI, 0.48-0.91)] while the less potent non-n-BP, etidronate, was not [pairwise HR: 0.89 (95% CI, 0.66-1.20)]. A direct comparison between n-BP and etidronate (n = 340 pairs) also suggested a better survival for n-BP [paired HR, 0.47 (95%CI, (95% CI, 031-0.70)] for n-BP vs. etidronate].

CONCLUSION

Compared to no treatment, nitrogen but not non-nitrogen bisphosphonates appear to be associated with better survival.

Association of Perioperative Transfusion with Recurrence and Survival After Resection of Distal Cholangiocarcinoma: A 10-Institution Study from the US Extrahepatic Biliary Malignancy Consortium

BACKGROUND

Perioperative allogeneic blood transfusion is associated with poor oncologic outcomes in multiple malignancies. The effect of blood transfusion on recurrence and survival in distal cholangiocarcinoma (DCC) is not known.

METHODS

All patients with DCC who underwent curative-intent pancreaticoduodenectomy at 10 institutions from 2000 to 2015 were included. Primary outcomes were recurrence-free (RFS) and overall survival (OS).

RESULTS

Among 314 patients with DCC, 191 (61%) underwent curative-intent pancreaticoduodenectomy. Fifty-three patients (28%) received perioperative blood transfusions, with a median of 2 units. There were no differences in baseline demographics or operative data between transfusion and no-transfusion groups. Compared with no-transfusion, patients who received a transfusion were more likely to have (+) margins (28 vs 14%; p = 0.034) and major complications (46 vs 16%; p < 0.001). Transfusion was associated with worse median RFS (19 vs 32 months; p = 0.006) and OS (15 vs 29 months; p = 0.003), which persisted on multivariable (MV) analysis for both RFS [hazard ratio (HR) 1.8; 95% confidence interval (CI) 1.1-3.0; p = 0.031] and OS (HR 1.9; 95% CI 1.1-3.3; p = 0.018), after controlling for portal vein resection, estimated blood loss (EBL), grade, lymphovascular invasion (LVI), and major complications. Similarly, transfusion of ≥ 2 pRBCs was associated with lower RFS (17 vs 32 months; p < 0.001) and OS (14 vs 29 months; p < 0.001), which again persisted on MV analysis for both RFS (HR 2.6; 95% CI 1.4-4.5; p = 0.001) and OS (HR 4.0; 95% CI 2.2-7.5; p < 0.001). The RFS and OS of patients transfused 1 unit was comparable to patients who were not transfused.

CONCLUSION

Perioperative blood transfusion is associated with decreased RFS and OS after resection for distal cholangiocarcinoma, after accounting for known adverse pathologic factors. Volume of transfusion seems to exert an independent effect, as 1 unit was not associated with the same adverse effects as ≥ 2 units.

Resection margin distance in extrahepatic cholangiocarcinoma: How much is enough?

455

Background: Surgical resection is required for curative treatment of patients with extra-hepatic cholangiocarcinoma (EH-CCA). The objective of this study was to determine if the distance of surgical margin was associated with outcome. Methods: Patients who underwent curative-intent resection for EH-CCA between 2000 and 2015 at 10 hepatobiliary centers across the U.S. were evaluated using prospectively collected data. Cox proportional hazard model was utilized to evaluate the influence of the extent of the margin on outcome. Results: 538 patients with EH-CCA who underwent curative-intent resection were included: 383 (71%) undergoing R0 resection, 153 (28%) undergoing R1 resection, and 2 with R2 resection. A negative surgical margin (R0) was associated with improved recurrence-free (RFS) and overall survival (OS) (RFS: 10.5% vs. 3.6% (R1) and OS: 25.8% vs. 9.3% (R1). Subsequently, further analysis on 161 patients with complete data on distance of resection margin, all undergoing R0 resection, was performed to assess the impact of extent of margin on outcome. On multi-variable analysis, the resection margin distance, analyzed as a continuous variable, was not associated with either improved RFS (RR 1.00, 95% CI 0.96-1.05; p 0.71) or OS (RR 0.99, 95% CI 0.96-1.01; p 0.49). Increasing age, increased tumor size, and LN metastasis were identified as independent predictors of OS; while RFS were mainly dependent on tumor size and LN metastasis (Table). Conclusions: Achieving R0 resection is acceptable for EH-CCA tumors, and obtaining additional margin does not confer a benefit on overall survival. Increasing age, tumor size, and LN metastasis are independent predictors of RFS and OS, but increased margin width is not associated with improvement in either. Multivariable analysis of factors affecting OS of patients with extra-hepatic CCA who underwent surgical resection, with significant factors noted in bold. [Table: see text]

Bacterial population dynamics after foliar fertilization of almond leaves

AIMS

To describe the effects of foliar fertilizer application on the bacterial populations of almond tree leaves.

METHODS AND RESULTS

We applied a commercially available foliar fertilizer or a water control onto the leaves of almond trees and collected leaves after 1, 7, 14 and 56 days and examined their bacterial populations by 16S rRNA gene sequence analysis. After 1 day, we observed significant differences in 3 of the 4 predominant bacterial phyla, and 5 of the 13 predominant bacterial families. After 7 days, we observed significant differences in all of the predominant phyla, and 8 of the 13 predominant families. After 14 days, the number of significant differences decreased, and after 56 days only 2 of the 13 predominant families differed significantly.

CONCLUSIONS

Foliar fertilization significantly altered the bacterial population structure of almond leaves as compared to the water control. While most of the observed perturbation was transient, significant differences remained after 56 days.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report describing the effects of foliar fertilization on the bacterial populations of almond leaves and provides new insights as to how this process alters the leaf bacterial population structure.

Defining Early Recurrence of Hilar Cholangiocarcinoma After Curative-intent Surgery: A Multi-institutional Study from the US Extrahepatic Biliary Malignancy Consortium

BACKGROUND

Time to tumor recurrence may be associated with outcomes following resection of hepatobiliary cancers. The objective of the current study was to investigate risk factors and prognosis among patients with early versus late recurrence of hilar cholangiocarcinoma (HCCA) after curative-intent resection.

METHODS

A total of 225 patients who underwent curative-intent resection for HCCA were identified from 10 academic centers in the USA. Data on clinicopathologic characteristics, pre-, intra-, and postoperative details and overall survival (OS) were analyzed. The slope of the curves identified by linear regression was used to categorize recurrences as early versus late.

RESULTS

With a median follow-up of 18.0 months, 99 (44.0%) patients experienced a tumor recurrence. According to the slope of the curves identified by linear regression, the functions of the two straight lines were y = -0.465x + 16.99 and y = -0.12x + 7.16. The intercept value of the two lines was 28.5 months, and therefore, 30 months (2.5 years) was defined as the cutoff to differentiate early from late recurrence. Among 99 patients who experienced recurrence, the majority (n = 80, 80.8%) occurred within the first 2.5 years (early recurrence), while 19.2% of recurrences occurred beyond 2.5 years (late recurrence). Early recurrence was more likely present as distant disease (75.1% vs. 31.6%, p = 0.001) and was associated with a worse OS (Median OS, early 21.5 vs. late 50.4 months, p < 0.001). On multivariable analysis, poor tumor differentiation (HR 10.3, p = 0.021), microvascular invasion (HR 3.3, p = 0.037), perineural invasion (HR 3.9, p = 0.029), lymph node metastases (HR 5.0, p = 0.004), and microscopic positive margin (HR 3.5, p = 0.046) were independent risk factors associated with early recurrence.

CONCLUSIONS

Early recurrence of HCCA after curative resection was common (~35.6%). Early recurrence was strongly associated with aggressive tumor characteristics, increased risk of distant metastatic recurrence and a worse long-term survival.