Development and Assessment of a Multi-Purpose Knowledge-Based Planning Model (RapidPlan) for Prostate Radiation

PURPOSE/OBJECTIVE(S)

RapidPlan (RP) is a knowledge-based planning (KBP) tool to improve plan quality, planning speed, and reduce inter-patient plan variability. For small to medium institutions, it is difficult to find sufficient patient numbers to configure a reliable KBP-RP model. This study aimed to build a multi-purpose KBP-RP model for prostate cancers.

MATERIALS/METHODS

A total of 124 prostate plans from 2018-2022 at our institution were selected to configure the initial RP model. After model training, outliers were removed. 77 patients were used for the final RP model. Three fine-tuned RP sub-models with different optimized constraints corresponding to prostate bed, prostate + seminal vesicles (SV), and prostate boost plans were generated. RP models were validated by comparing plan quality with the original manually optimized plans (MP). 54 independent plans were selected to validate the RP models. Validation included: dose to 99% and 2% of PTV (D99%, D2%), PTV conformity index (CI); for organs at risk (OARs), volume receiving >70Gy and >60Gy (V70Gy, V60Gy) to bladder and rectum, maximum dose (Dmax) to femur heads (FHs) and small bowel. Statistical t-test analysis was performed with a significance of p<0.05.

RESULTS

A total of 48/54 model-based plans were clinically approved after single RP optimization. 6/54 failed plans were prostate bed plans and were deemed acceptable after additional minor constraint adjustments. For PTV, D99%, D2%, and CI were comparable (p>0.05) to MP. Bladder and rectum V70Gy were comparable (p>0.05), and V60Gy were significantly lower to MP (p<0.05), with an average Dmean of 23.21±14.58Gy and 16.41±10.63Gy vs 26.36±16.89Gy and 18.24±12.81Gy for RP and MP. RP significantly reduced Dmax to FHs and small bowel (p<0.05), with average Dmax of 34.95±6.06Gy and 35.62±18.99Gy vs 36.81±7.05Gy and 38.14±17.81Gy, respectively.

CONCLUSION

Multi-purpose prostate RP model was configured and approved plans were generated after single optimization. Prostate RP plans had equivalent PTV coverage with better or comparable OAR constraints.

Data on the effects of ECM rigidity on actomyosin contractility and invadopodia activity in individual versus pairs of head and neck squamous cell carcinoma cells

Migration through the extracellular matrix (ECM) is essential for cancer cells to escape the primary tumor and invade neighboring tissues with the potential for metastasis [1]. To penetrate tissue barriers, migrating cancer cells degrade the ECM with actin-rich membrane protrusions called invadopodia [2]. We have previously found that invadopodial ECM degradation is regulated by ECM rigidity in a process mediated by contractile forces in individual head and neck squamous cell carcinoma (HNSCC) cells [3], [4]. However, cancer cells often migrate together and interact with each other to alter their actomyosin contractility in response to the biomechanical properties of the ECM [5]. Therefore, we tested whether ECM rigidity promotes biomechanical interactions between cancer cells to enhance proteolytic activity. Using a minimal model of two HNSCC cells in physical contact, we provide data here that actomyosin contractility, invadopodia formation, and ECM degradation increase in response to ECM rigidity when cells are in pairs versus individual cells using traction force and invadopodia assays.

0838 Sex Specific Changes in Sleep Macro-Structure With Obstructive Sleep Apnea in a Large Clinical Population of Older Adults

Introduction

Sleep architecture is influenced by age and sex and is disrupted by obstructive sleep apnea (OSA) and periodic limb movements (PLM) of sleep. Although increasing OSA severity is thought to decrease both REM and slow wave sleep (SWS), it may do so in non-linear ways. Here, we aim to 1) compare sleep macrostructure between older men and women, 2) compare metrics of total and REM-specific OSA severity between older men and women, and 3) examine associations between metrics of OSA severity and REM sleep and SWS in a clinical sample.

Methods

Clinical in-lab diagnostic polysomnography (PSG) in adults ≥64 years of age from the greater New York area recorded between 2006- 2016 were collated including demographic and traditional sleep scoring metrics. Studies where TST &lt; 4 hours were removed. Demographic, sleep macrostructure, OSA (AHI4% & AHI3A criteria), pulse oximetry (SpO2) nadir and PLM measures were compared according to sex.

Results

PSGs from 1282 older adults (average age 70 years in both sexes, 41% female) were included in the analyses. Women had a significantly greater SWS% (14.5 vs 7.9, p&lt;0.001) and less N1% (18.2 vs 24.4, p&lt;0.001), without significant differences in TST, N2%, REM%, sleep efficiency or SpO2 nadir. Men had significantly higher all-sleep OSA (median AHI4% 8.8 vs 11.1, p=0.0004; median AHI3A 24.4 vs 27.9, p=0.003) and PLM’s (4.0 vs 7.6/hour, p=0.008) but women had significantly more OSA during REM sleep (median REM AHI4% 16.7 vs 14.0, p=0.01; median REM AHI3A 32.6 vs 27.4, p=0.0002). Inverse non-linear associations were observed between OSA severity and %SWS and %REM with a unique pattern for each sleep stage. The pattern between men and women within each stage appeared similar.

Conclusion

In this clinical sample of older adults, women exhibit a greater proportion of SWS and worse REM-related OSA then men. Increasing OSA severity is associated with non-linear reductions in %SWS and %REM, and we plan to further investigate these relationships and sexual dimorphism by using quantitative analysis of PSG signals for more precise measures of slow wave activity and breathing physiology than traditional sleep scoring metrics.

Support

R01AG056682

0966 Sleep-Wake Patterns in Mothers and Children in a Rural Community With Limited Access to Electricity: Results from the Ghana Randomized Air Pollution and Health Study

Introduction

Studies measuring objective sleep duration in rural/indigenous populations are limited, showing sleep duration similar to that of industrialized countries. Little is known about sleep duration in women of reproductive age, and children within these populations. Our study is the first to objectively characterize sleep in mothers and children in an agrarian community with limited access to electricity, utilizing data from the Ghana Randomized Air Pollution and Heath Study (GRAPHS).

Methods

The GRAPHS cohort, a cluster-randomized trial, evaluated the efficacy of clean fuels on birthweight and infant pneumonia incidence in central Ghana. The study initially recruited pregnant women and newborns in 2013. This study is now utilizing wrist-actigraphy to analyze sleep-wake patterns among mothers and children of GRAPHS. We have thus far analyzed actigraphy in 39 mothers and 49 children (including 25 mother-child pairs), using the Motionlogger-MicroWatch with the Cole-Kripke algorithm to assess total sleep time (TST). We report baseline characteristics and sleep-wake patterns of our sample.

Results

Mean age of mothers was 33.5 years, (range 22-48), and mean age of children was 3.9 years (3-4). Average nights recorded were 4 (standard deviation [SD] 2.1). For mothers, average median time-in-bed was 7.9 (SD 1.2) hours, TST was 6.4 (SD .9) hours, and sleep efficiency was 82% (SD 7.9). Median bedtime was 9:33pm (SD 1.5 hours), and median wake-time was 5:56am (SD 1.4 hours). For children, average median time-in-bed was 9.9 (SD 1.0) hours, TST was 8.2 (SD 0.9) hours, and sleep efficiency was 83% (SD 6). Median bedtime was 8:03pm (SD 0.8 hours), and median wake-time was 6:06am (SD 0.6 hours). There was no correlation between sleep measures in mother-child pairs.

Conclusion

In an agrarian Ghanaian community with limited access to electricity, objective sleep measures in women were similar to prior studies conducted in indigenous/rural populations of developing African countries (Ndiaye et.al.2007, Samson et.al.2016), though data in children is lacking for comparison. When compared with post-industrialized countries, objective sleep measures for this age group of non-gravid women are sparse. In toddlers however, TST was lower in our cohort when compared with objective sleep amongst toddlers in industrialized nations.

Support

2K24HL109156-06A1

1150 Obstructive Sleep Apnea-dependent Racial/ethnic And Sex-specific Mechanisms Underlying Alzheimer’s Disease Risk: A Retrospective Cohort Analysis Of In-lab PSG Sleep Study Data

Introduction

We examined race and sex-specific biologic mechanisms of the relationship between obstructive sleep apnea (OSA) and incident AD.

Methods

Retrospective cohort analysis utilizing in-lab PSG sleep study data conducted among older adults between 2001 and 2005. OSA was defined using AHI4%. Participants had no history of cognitive decline or AD at baseline and included 663 (284 Non-Hispanic White (NHW), 207 Black/African-American (AA) and 172 Hispanic) OSA-patients matched on age, sex, race, BMI, 1:1 ratio to 663 (unexposed cohort I from sleep clinic) and 1:4 ratio to 2652 (unexposed cohort II from non-sleep clinics) non-OSA individuals. Incident AD was assessed annually from 2001-2013 with ICD-9-CM code 331.0. Adjusted cox proportional hazard regression models examined race and sex-specific biologic mechanisms including hypoxia, fragmentation and duration measures of OSA and AD risk.

Results

Of the 3,978 participants, 2,148 (54%) were women. Mean age at baseline was 72.6 (7.3) years. Over a mean follow-up time of 8.6 (1.4) years, 358 (9%) individuals (212 female) developed AD (119 NHW, 134 AAs, and 105 Hispanics). Relative to non-OSA individuals, OSA-patients had a higher risk of incident AD, with AAs and females showing stronger risk estimates (aHR: 2.24, 1.83, and 1.73, P &lt;.001 for all, for AAs, Hispanics and NHW respectively; and aHR: 2.38, and 1.37, P &lt;.001 for all, for female and male respectively). Measures of hypoxia, sleep fragmentation and sleep duration were associated with increase AD risk (P &lt;.01 for all). Relative to NHW, AAs and Hispanics demonstrated up to 20% stronger effects/estimates on hypoxia and sleep duration measures. Relative to males, females demonstrated up to 25% stronger effects/estimates on sleep fragmentation measures, and 15% weaker effects/estimates on hypoxia measures (P &lt;.01 for all).

Conclusion

Among OSA-patients, mechanisms related to hypoxia, sleep fragmentation and duration measures increase AD risk and may underlie race/ethnicity and sex disparities in AD.

Support

NIH/NIA/NHLBI (L30-AG064670, CIRAD P30AG059303 Pilot, T32HL129953, R01HL118624, R21AG049348, R21AG055002, R01AG056031, R01AG022374, R21AG059179, R01AG056682, R01AG056531, K07AG05268503, K23HL125939)

1153 Association Of Nocturnal Sleep Disturbance And Prospective Cognitive Decline In Cognitive Normal Elderly: Findings From The National Alzheimer’s Coordinating Center Uniform Dataset

Introduction

We determined whether nocturnal sleep disturbance (NSD) is associated with prospective cognitive decline in clinically normal older adults

Methods

Prospective longitudinal study utilizing data from the National Alzheimer’s Coordinating Center (NACC) Uniform Data set (UDS). NSD data, as characterized by the Neuropsychiatric Inventory Questionnaire (NPI-Q), were derived from 10,600 participants at baseline, with at least one UDS follow-up visit, from 32 National Institute of Aging Alzheimer’s Disease Research Centers (ADRC). Prospective cognitive decline was characterized as incident mild cognitive impairment (MCI) diagnosis during UDS follow-up. Logistic mixed-effects model with random intercept and slope examined associations between the NSD and longitudinal cognitive decline. All models included age at baseline, sex, years of education, APOE ε4 status and their interactions with time. Time was operationalized as years from baseline for each participant.

Results

Of the 10,600 cognitively normal participants at baseline, 1,017 (8.6%) had NSD. The proportion of males versus females with sleep problems was 10.1% vs. 9.3% respectively. For participants with NSD and no NSD, the mean (SD) age was 71 (7.3) and 70 (5.7) years and average follow-up time was 5.2 (2.6) and 4.9 (2.7) years, respectively. Participants with NSD were significantly more likely to develop incident MCI during UDS follow-up (OR: 1.42, p =.003). The interaction of NSD with time was significant (p&lt; .001) suggesting an increase in the likelihood of conversion to MCI increased over time. Furthermore, there were significant differences in mean conversion rates to MCI in the NSD group when the previous time-point was compared to the next (p&lt;01), with a time dependent dose response in the risk of conversion to MCI observed.

Conclusion

In elderly cognitive-normal individuals, nocturnal sleep disturbance is associated with a time-dependent progression risk to MCI. These findings are consistent with the role of disturbed sleep in the development of Alzheimer’s Disease.

Support

NIH/NIA/NHLBI (L30-AG064670, CIRAD P30AG059303 Pilot, T32HL129953, R01HL118624, R21AG049348, R21AG055002, R01AG056031, R01AG022374, R21AG059179, R01AG056682, R01AG056531, K07AG05268503, K23HL125939)

Data on the negative regulation of invadopodia activity by MLCK

Actomyosin contractility can promote extracellular matrix (ECM) degradation by invadopodia in cancer cells. However, we previously found that inhibiting myosin light chain kinase (MLCK) with siRNA did not change force generation by the head and neck squamous cell carcinoma (HNSCC) cell line SCC-61. We provide data here that this targeted method of MLCK knockdown (KD) resulted in a significant increase in the amount of ECM degradation, number of actively degrading invadopodia, and the number of total invadopodia formed. These data are related to the research article entitled “Matrix rigidity differentially regulates invadopodia activity through ROCK1 and ROCK2” Jerrell and Parekh, 2016.

The altered mechanical phenotype of fetal fibroblasts hinders myofibroblast differentiation

During the dermal wound healing process, the mechanical rigidity of the newly deposited extracellular matrix and transforming growth factor‐β1 promote the transition of fibroblasts into myofibroblasts. Myofibroblasts generate large cellular forces that contract and remodel the extracellular matrix leading to scar formation. In contrast, myofibroblasts are not detected in fetal dermal wounds which are more compliant and contain less transforming growth factor‐β1 than adult wounds. Instead, fetal fibroblasts orchestrate scarless healing of dermal wounds resulting in healed tissues that resemble uninjured dermis. While these biomechanical differences suggest that the fetal wound environment promotes smaller cellular forces which enable regeneration, previous studies indicate that fetal fibroblasts have unique contractile properties that may facilitate scarless dermal repair. Therefore, we tested whether physiologic wound rigidities and transforming growth factor‐β1 induce contractile forces and myofibroblast differentiation of fetal dermal fibroblasts. In comparison to their adult dermal counterparts, we found that fetal fibroblasts exhibit a deficient contractile response to rigid extracellular matrix and transforming growth factor‐β1. Our data suggest that the contractile phenotype of fetal dermal fibroblasts limits their cellular force production and prevents their ability to differentiate into myofibroblasts.

Cadherin-11 as a regulator of valve myofibroblast mechanobiology

Cadherin-11 (CDH11) is upregulated in a variety of fibrotic diseases, including arthritis and calcific aortic valve disease. Our recent work has identified CDH11 as a potential therapeutic target and shown that treatment with a CDH11 functional blocking antibody can prevent hallmarks of calcific aortic valve disease in mice. The present study investigated the role of CDH11 in regulating the mechanobiological behavior of valvular interstitial cells believed to cause calcification. Aortic valve interstitial cells were harvested from Cdh11^+/+, Cdh11^+/-, and Cdh11^-/- immortomice. Cells were subjected to inflammatory cytokines transforming growth factor (TGF)-β₁ and IL-6 to characterize the molecular mechanisms by which CDH11 regulates their mechanobiological changes. Histology was performed on aortic valves from Cdh11^+/+, Cdh11^+/-, and Cdh11^-/- mice to identify key responses to CDH11 deletion in vivo. We showed that CDH11 influences cell behavior through its regulation of contractility and its ability to bind substrates via focal adhesions. We also show that transforming growth factor-β₁ overrides the normal relationship between CDH11 and smooth muscle α-actin to exacerbate the myofibroblast disease phenotype. This phenotypic switch is potentiated through the IL-6 signaling axis and could act as a paracrine mechanism of myofibroblast activation in neighboring aortic valve interstitial cells in a positive feedback loop. These data suggest CDH11 is an important mediator of the myofibroblast phenotype and identify several mechanisms by which it modulates cell behavior. NEW & NOTEWORTHY Cadherin-11 influences valvular interstitial cell contractility by regulating focal adhesions and inflammatory cytokine secretion. Transforming growth factor-β₁ overrides the normal balance between cadherin-11 and smooth muscle α-actin expression to promote a myofibroblast phenotype. Cadherin-11 is necessary for IL-6 and chitinase-3-like protein 1 secretion, and IL-6 promotes contractility. Targeting cadherin-11 could therapeutically influence valvular interstitial cell phenotypes in a multifaceted manner.

Expression of human papillomavirus oncoproteins E6 and E7 inhibits invadopodia activity but promotes cell migration in HPV-positive head and neck squamous cell carcinoma cells

Background

The rapid increase in the incidence of head and neck squamous cell carcinoma (HNSCC) is caused by high‐risk human papillomavirus (HPV) infections. The HPV oncogenes E6 and E7 promote carcinogenesis by disrupting signaling pathways that control survival and proliferation. Although these cancers are often diagnosed with metastases, the mechanisms that regulate their dissemination are unknown.

Aims

The aim of this study was to determine whether the HPV‐16 E6 and E7 oncogenes affected the invasive and migratory properties of HNSCC cells which promote their spread and metastasis.

Methods and results

Invasiveness was determined using invadopodia assays which allow for quantitation of extracellular matrix (ECM) degradation by invadopodia which are proteolytic membrane protrusions that facilitate invasion. Using cell lines and genetic manipulations, we found that HPV inhibited invadopodia activity in aggressive cell lines which was mediated by the E6 and E7 oncogenes. Given these findings, we also tested whether HPV caused differences in the migratory ability of HNSCC cells using Transwell assays. In contrast to our invadopodia results, we found no correlation between HPV status and cell migration; however, blocking the expression of the E6 and E7 oncoproteins in a HPV‐positive (HPV⁺) HNSCC cell line resulted in decreased migration.

Conclusions

Our data suggest that the E6 and E7 oncoproteins are negative regulators of invadopodia activity but may promote migration in HPV⁺ HNSCC cells. Despite the need for ECM proteolysis to penetrate most tissues, the unique structure of the head and neck tissues in which these cancers arise may facilitate the spread of migratory cancer cells without significant proteolytic ability.

Abstract P4-10-08: Withdrawn

This abstract was withdrawn by the authors.

The ROCK isoforms differentially regulate the morphological characteristics of carcinoma cells

Rho-associated kinase (ROCK) activity drives cell migration via actomyosin contractility. During invasion, individual cancer cells can transition between 2 modes of migration, mesenchymal and amoeboid. Changes in ROCK activity can cause a switch between these migration phenotypes which are defined by distinct morphologies. However, recent studies have shown that the ROCK isoforms are not functionally redundant as previously thought. Therefore, it is unclear whether the ROCK isoforms play different roles in regulating migration phenotypes. Here, we found that ROCK1 and ROCK2 differentially regulate carcinoma cell morphology resulting in intermediate phenotypes that share some mesenchymal and amoeboid characteristics. These findings suggest that the ROCK isoforms play unique roles in the phenotypic plasticity of mesenchymal carcinoma cells which may have therapeutic implications.

The Contractile Phenotype of Dermal Fetal Fibroblasts in Scarless Wound Healing

PURPOSE OF REVIEW

Injured skin in the mammalian fetus can heal regeneratively due to the ability of fetal fibroblasts to effectively reorganize the extracellular matrix (ECM). This process occurs without fetal fibroblasts differentiating into highly contractile myofibroblasts which cause scarring and fibrosis in adult wounds. Here, we provide a brief review of fetal wound healing and the evidence supporting a unique contractile phenotype in fetal fibroblasts. Furthermore, we discuss the biomechanical role of the ECM in driving myofibroblast differentiation in wound healing and the implications for new clinical modalities based on the biophysical properties of fetal fibroblasts.

RECENT FINDINGS

We and others have found that fetal fibroblasts are refractory to the environmental stimuli necessary for myofibroblast differentiation in adult wound healing including mechanical stress.

SUMMARY

Understanding the biomechanical mechanisms that regulate the contractile phenotype of fetal fibroblasts may unlock new avenues for anti-scarring therapies that target myofibroblast differentiation of adult fibroblasts.

Comparison of Post-Liver Transplantation Outcomes in Portopulmonary Hypertension and Pulmonary Venous Hypertension: A Single-Center Experience

BACKGROUND

In potential liver transplant candidates, pulmonary vascular diseases, including portopulmonary hypertension (PoPH) and pulmonary venous hypertension (PVH), can be associated with high morbidity and mortality. Although there are clear guidelines regarding management and transplant listing criteria for patients with PoPH, the listing criteria for PVH are not well defined.

OBJECTIVE

The aim of this study was to describe and compare the perioperative and postoperative morbidity and mortality associated with PoPH and PVH in patients undergoing liver transplantation.

METHODS

We conducted a retrospective observational study of all patients referred for liver transplantation to our center between 2005 and 2015 who underwent a right heart catheterization (RHC) for screening for pulmonary hypertension as suggested by initial echocardiography. Based on the RHC data, the patients were grouped into no pulmonary hypertension (No PH), PoPH, and PVH categories. In patients who underwent liver transplantation, we recorded vital status intraoperatively and at 30 days and 1-year post-transplant, and we recorded the incidence of postoperative cardiopulmonary and renal complications.

RESULTS

Of the 134 patients who underwent RHC as part of the initial transplant evaluation, 50 patients were successfully transplanted. There was 1 intraoperative death in the PoPH group. No significant difference in mortality was noted between the No PH, PoPH, and PVH groups intraoperatively and 30 days after liver transplantation. At 1 year, the survival rates were 100%, 69.2%, and 94.1% in the No PH, PoPH, and PVH groups, respectively. With respect to cardiopulmonary and renal complications, no statistically significant difference was noted among the groups, though there was a trend toward increased post-transplant reversible pulmonary complications in the PVH group.

CONCLUSION

Our findings suggest that the post-transplant outcomes of patients with PoPH and PVH are similar. In light of the growing recognition of diastolic dysfunction and cirrhotic cardiomyopathy in decompensated cirrhotic patients at the time of transplant, the issue of pulmonary hypertension related to PVH will gain increasing importance as we assess these patients for transplantation. Therefore, future studies are needed to define evidence based guidelines to determine candidacy for liver transplantation in the context of PVH.

Prognostic impact of FOXF1 polymorphisms in gastric cancer patients

A recent genome-wide association study identified seven single-nucleotide polymorphisms (SNPs) in region 16q24, near the Forkhead box-F1 (FOXF1) gene, which confer susceptibility to esophageal adenocarcinoma. We examined whether these SNPs are associated with clinical outcomes in gastric cancer (GC) patients in Japan and the United States. A total of 362 patients were included in this study: 151 Japanese GC patients treated with first-line S1 plus CDDP (training cohort) and 211 GC patients from Los Angeles County (LAC; validation cohort). Genomic DNA was isolated from whole blood or tumor tissue and analyzed by PCR-based direct DNA sequencing. Cox proportional hazard regression analyses were used to assess relationships between FOXF1 SNPs and progression-free survival (PFS) and overall survival (OS). FOXF1 rs3950627 was significantly associated with survival in both the training and validation cohorts. Japanese patients with the C/C genotype had a longer PFS (median 8.2 vs 5.3 months, hazard ratio (HR) 1.44, P=0.037) and OS (median 16.4 vs 12.2 months, HR 1.44, P=0.043) compared to patients with any A allele. Similarly, LAC patients with the C/C genotype had improved OS (3.9 vs 2.3 years, HR 1.5, P=0.022). Subgroup analyses showed these associations were specific to male patients and primary tumor subsite. Our findings suggest that FOXF1 rs3950627 might be a promising prognostic marker in GC patients.

GW627368X inhibits proliferation and induces apoptosis in cervical cancer by interfering with EP4/EGFR interactive signaling

PGE2, the major product of cyclooxygenases implicated in carcinogenesis, is significantly upregulated in cervical cancer. PGE2 via prostanoid receptor EP4 stimulates proliferation and motility while inhibiting apoptosis and immune surveillance. It promotes angiogenesis by stimulating the production of pro-angiogenic factors. The present study demonstrates GW627368X, a highly selective competitive EP4 antagonist, which hinders cervical cancer progression by inhibiting EP4/epithelial growth factor receptor (EGFR) interactive signaling. GW627368X reduced protein kinase A (PKA) phosphorylation which in turn leads to decreased cAMP response element-binding protein (CREB) activation. Decreased PKA phosphorylation also directly enhanced Bax activity and in part reduced glycogen synthase kinase 3 (GSK3)β phosphorylation. Owing to the interactive signaling between EP4 and EGFR, GW627368X lowered EGFR phosphorylation in turn reducing Akt, mitogen-activated protein kinase (MAPK) and GSK3β activity significantly. Sublethal dose of GW627368X was found to reduce the nuclear translocation of β-catenin in a time dependent manner along with time-dependent decrease in cytoplasmic as well as whole-cell β-catenin. Decreased CREB and β-catenin transcriptional activity restricts the aberrant transcription of key genes like EP4, cyclooxygenase (COX)-2, vascular endothelial growth factor and c-myc, which ultimately control cell survival, proliferation and angiogenesis. Reduced activity of EGFR resulted in enhanced expression of 15-hydroxyprostaglandin dehydrogenase increasing PGE2 degradation thereby blocking a positive feedback loop. In xenograft model, dose-dependent decrease in cancer proliferation was observed characterized by reduction in tumor mass and volume and a marked decrease in Ki67 expression. A diminished CD31 specific staining signified decreased tumor angiogenesis. Reduced expression of pAkt, pMAPK, pEGFR and COX-2 validated in vitro results. GW627368X therefore effectively inhibits tumor survival, motility, proliferation and angiogenesis by blocking EP4/EGFR interactive signaling. EP4 is a potent therapeutic target in cervical cancer and can be explored in combination with conventional therapies to attain superior outcomes and to overcome complications associated with organ toxicities, therapeutic resistance and disease relapse.

Matrix rigidity differentially regulates invadopodia activity through ROCK1 and ROCK2

ROCK activity increases due to ECM rigidity in the tumor microenvironment and promotes a malignant phenotype via actomyosin contractility. Invasive migration is facilitated by actin-rich adhesive protrusions known as invadopodia that degrade the ECM. Invadopodia activity is dependent on matrix rigidity and contractile forces suggesting that mechanical factors may regulate these subcellular structures through ROCK-dependent actomyosin contractility. However, emerging evidence indicates that the ROCK1 and ROCK2 isoforms perform different functions in cells suggesting that alternative mechanisms may potentially regulate rigidity-dependent invadopodia activity. In this study, we found that matrix rigidity drives ROCK signaling in cancer cells but that ROCK1 and ROCK2 differentially regulate invadopodia activity through separate signaling pathways via contractile (NM II) and non-contractile (LIMK) mechanisms. These data suggest that the mechanical rigidity of the tumor microenvironment may drive ROCK signaling through distinct pathways to enhance the invasive migration required for cancer progression and metastasis.

Regulation of invadopodia by mechanical signaling

Mechanical rigidity in the tumor microenvironment is associated with a high risk of tumor formation and aggressiveness. Adhesion-based signaling driven by a rigid microenvironment is thought to facilitate invasion and migration of cancer cells away from primary tumors. Proteolytic degradation of extracellular matrix (ECM) is a key component of this process and is mediated by subcellular actin-rich structures known as invadopodia. Both ECM rigidity and cellular traction stresses promote invadopodia formation and activity, suggesting a role for these structures in mechanosensing. The presence and activity of mechanosensitive adhesive and signaling components at invadopodia further indicates the potential for these structures to utilize myosin-dependent forces to probe and remodel their ECM environments. Here, we provide a brief review of the role of adhesion-based mechanical signaling in controlling invadopodia and invasive cancer behavior.

Variations in genes regulating tumor-associated macrophages (TAMs) to predict outcomes of bevacizumab-based treatment in patients with metastatic colorectal cancer: results from TRIBE and FIRE3 trials

BACKGROUND

Tumor-associated macrophages (TAMs) with the M2-like phenotype are regulated by mainly NF-kB pathway including TBK1, which can influence tumor progression by secretion of proangiogenic factors such as vascular endothelial growth factor. The CCL2/CCR2 axis, histidine-rich glycoprotein (HRG), and placenta growth factor (PIGF) play a critical role in the polarization of M1/M2 phenotypes and the recruitment of TAMs to tumor microenvironment. We therefore hypothesized that variations in genes involved in regulating TAMs may predict clinical outcomes of bevacizumab treatment in patients with metastatic colorectal cancer (mCRC).

PATIENTS AND METHODS

We analyzed genomic DNA extracted from samples of patients receiving bevacizumab plus FOLFIRI as a first-line treatment using PCR-based direct sequencing. Twelve functional single-nucleotide polymorphisms in eight genes (CCL2, CCR2, HRG, PIGF, NFKB1, TBK1, CCL18, and IRF3) were tested for associations with clinical outcomes in a discovery cohort of 228 participants in TRIBE trial (NCT00719797), then validated in 248 KRAS exon2 (KRAS) wild-type participants in FIRE3 trial (NCT00433927). FIRE3-cetuximab cohort served as a negative control.

RESULTS

TBK1 rs7486100 was significantly associated with overall survival in 95 KRAS wild-type patients of TRIBE cohort in univariate analysis and had a strong trend in multivariable analysis; furthermore, the association of the T allele was observed for progression-free survival (PFS) in both univariate and multivariable analyses in FIRE3-bevacizumab but not cetuximab cohort. CCL2 rs4586, CCL18 rs14304, and IRF3 rs2304205 had univariate and multivariable correlations with PFS in KRAS mutant patients of the TRIBE cohort, whereas they had no correlations in KRAS wild-type patients of the TRIBE cohort. No association was seen in control cohort.

CONCLUSIONS

Our study demonstrates for the first time that variations in genes regulating TAMs-related functions are significantly associated with clinical outcomes in mCRC patients treated with bevacizumab-containing chemotherapy. These results also suggest that some TAM-related gene variations may predict outcomes of bevacizumab treatment in KRAS status-dependent manner.

Variations in genes involved in dormancy associated with outcome in patients with resected colorectal liver metastases

BACKGROUND

Tumor dormancy has been described as a state of hibernation. Dormancy can be switched to proliferation by different pathways, which may play a critical role in tumor recurrence. In this study, we investigated genetic variations within genes involved in tumor dormancy and their association with recurrence and outcome in patients with colorectal liver metastases (CLM) who underwent neoadjuvant bevacizumab-based chemotherapy.

PATIENTS AND METHODS

Genomic DNA was extracted from resected CLM (FFPE) from 149 patients. Single-nucleotide polymorphisms (SNPs) in 14 genes associated with dormancy were analyzed by direct Sanger DNA sequencing and evaluated for response, recurrence-free survival (RFS), overall survival (OS) and recurrence patterns.

RESULTS

NME1 rs34214448 C>A was significantly associated with RFS in univariable analysis (P = 0.039) and with intrahepatic recurrence (P = 0.014). NOTCH3 rs1044009 T>C and CD44 rs8193 C>T showed a significant difference in 3-year OS rates (P = 0.004 and P = 0.042, respectively). With respect to radiological response, CD44 rs8193 C>T variant genotypes were associated with a significantly higher response rate (P = 0.033). Recursive partitioning analyses revealed that Dll4 rs12441495 C>G, NME1 rs34214448 C>A and NOTCH3 rs1044009 T>C were the dominant SNPs predicting histological response, RFS and OS, respectively.

CONCLUSION

Our data suggest that gene variations within genes involved in tumor dormancy pathways are associated with response and outcome in patients with resected CLM. These data may lead to new and more effective treatment strategies targeting tumor dormancy.