The effect of social determinants of health on utilization of surgical treatment for hepatocellular carcinoma patients

BACKGROUND

A paucity of data exists on how social determinants of health (SDOH) influence treatment for Hepatocellular carcinoma (HCC). We investigated associations between SDOH (healthcare access, education, social/community context, economic stability, and built/neighborhood environment) and receipt of surgery.

METHODS

The Pennsylvania Liver Cancer Registry was linked with neighborhood SDOH from the American Community Survey. Multilevel logistic regression models with patient and neighborhood SDOH variables were developed.

RESULTS

Of 9423 HCC patients, 2393 were stage I. Only 36.3% of stage I patients received surgery. Black patients had significantly lower odds of surgery vs Whites (OR = 0.73; p < 0.01), but not after adjustments for SDOH. All 5 SDOH domains were associated with odds of surgery overall; 2 domains were associated in Stage I patients, social context (e.g., racial concentration, p = 0.03) and insurance access (p < 0.01).

CONCLUSIONS

SDOH impact utilization of surgery for HCC. Findings can guide healthcare professionals to create programs for populations at risk for poor liver cancer outcomes.

Risk of Lymph Node Metastasis in T1b Gastric Cancer: An International Comprehensive Analysis from the Global Gastric Group (G3) Alliance

OBJECTIVE

We sought to define criteria associated with low lymph node metastasis risk in patients with submucosal (pT1b) gastric cancer from 3 Western and 3 Eastern countries.

SUMMARY BACKGROUND DATA

Accurate prediction of lymph node metastasis risk is essential when determining the need for gastrectomy with lymph node dissection following endoscopic resection. Under present guidelines, endoscopic resection is considered definitive treatment if submucosal invasion is only superficial, but this is not routinely assessed.

METHODS

Lymph node metastasis rates were determined for patient groups defined according to tumor pathological characteristics. Clinicopathological predictors of lymph node metastasis were determined by multivariable logistic regression and used to develop a nomogram in a randomly selected subset that was validated in the remainder. Overall survival was compared between Eastern and Western countries.

RESULTS

Lymph node metastasis was found in 701 of 3166 (22.1%) Eastern and 153 of 560 (27.3%) Western patients. Independent predictors of lymph node metastasis were female sex, tumor size, distal stomach location, lymphovascular invasion, and moderate or poor differentiation. Patients fulfilling the National Comprehensive Cancer Network guideline criteria, excluding the requirement that invasion not extend beyond the superficial submucosa, had a lymph node metastasis rate of 8.9% (53/594). Excluding moderately differentiated tumors lowered the rate to 3.4% (10/296). The nomogram's area under the curve was 0.690. Regardless of lymph node status, overall survival was better in Eastern patients.

CONCLUSIONS

The lymph node metastasis rate was lowest in patients with well differentiated tumors that were ≤3 cm and lacked lymphovascular invasion. These criteria may be useful in decisions regarding endoscopic resection as definitive treatment for pT1b gastric cancer.

Combined Blockade of MEK and CDK4/6 Pathways Induces Senescence to Improve Survival in Pancreatic Ductal Adenocarcinoma

Activating KRAS mutations, a defining feature of pancreatic ductal adenocarcinoma (PDAC), promote tumor growth in part through the activation of cyclin-dependent kinases (CDK) that induce cell-cycle progression. p16INK4a (p16), encoded by the gene CDKN2A, is a potent inhibitor of CDK4/6 and serves as a critical checkpoint of cell proliferation. Mutations in and subsequent loss of the p16 gene occur in PDAC at a rate higher than that reported in any other tumor type and results in Rb inactivation and unrestricted cellular growth. Therefore, strategies targeting downstream RAS pathway effectors combined with CDK4/6 inhibition (CDK4/6i) may have the potential to improve outcomes in this disease. Herein, we show that expression of p16 is markedly reduced in PDAC tumors compared with normal pancreatic or pre-neoplastic tissues. Combined MEK inhibition (MEKi) and CDK4/6i results in sustained downregulation of both ERK and Rb phosphorylation and a significant reduction in cell proliferation compared with monotherapy in human PDAC cells. MEKi with CDK4/6i reduces tumor cell proliferation by promoting senescence-mediated growth arrest, independent of apoptosis in vitro We show that combined MEKi and CDK4/6i treatment attenuates tumor growth in xenograft models of PDAC and improves overall survival over 200% compared with treatment with vehicle or individual agents alone in Ptf1acre/+ ;LSL-KRASG12D/+ ;Tgfbr2flox/flox (PKT) mice. Histologic analysis of PKT tumor lysates reveal a significant decrease in markers of cell proliferation and an increase in senescence-associated markers without any significant change in apoptosis. These results demonstrate that combined targeting of both MEK and CDK4/6 represents a novel therapeutic strategy to synergistically reduce tumor growth through induction of cellular senescence in PDAC.

Src kinase inhibition restores E-cadherin expression in dasatinib-sensitive pancreatic cancer cells

The Src family of non-receptor tyrosine kinases are frequently activated in pancreatic ductal adenocarcinoma (PDAC), contributing to disease progression through downregulation of E-cadherin and induction of epithelial-to-mesenchymal transition (EMT). The purpose of this study was to examine the efficacy of Src kinase inhibition in restoring E-cadherin levels in PDAC. Immunohistochemical analysis of human PDAC samples showed Src activation is inversely correlated with E-cadherin levels. Protein and mRNA levels of E-cadherin, the gene expression of its various transcriptional repressors (Zeb1, Snail, Slug, LEF-1, TWIST), and changes in sub-cellular localization of E-cadherin/β-catenin in PDAC cells were characterized in response to treatment with the Src inhibitor, dasatinib (DST). DST repressed Slug mRNA expression, promoted E-cadherin transcription, and increased total and membranous E-cadherin/β-catenin levels in drug-sensitive PDAC cells (BxPC3 and SW1990), however no change was observed in drug-resistant PANC1 cells. BxPC3, PANC1, and MiaPaCa-2 flank tumor xenografts were treated with DST to examine changes in E-cadherin levels in vivo. Although DST inhibited Src phosphorylation in all xenograft models, E-cadherin levels were only restored in BxPC3 xenograft tumors. These results suggest that Src kinase inhibition reverses EMT in drug-sensitive PDAC cells through Slug-mediated repression of E-cadherin and identifies E-cadherin as potential biomarker for determining response to DST treatment.

Inverse Correlation of STAT3 and MEK Signaling Mediates Resistance to RAS Pathway Inhibition in Pancreatic Cancer

Major contributors to therapeutic resistance in pancreatic ductal adenocarcinoma (PDAC) include Kras mutations, a dense desmoplastic stroma that prevents drug delivery to the tumor, and activation of redundant signaling pathways. We have previously identified a mechanistic rationale for targeting STAT3 signaling to overcome therapeutic resistance in PDAC. In this study, we investigate the molecular mechanisms underlying the heterogeneous response to STAT3 and RAS pathway inhibition in PDAC. Effects of JAK/STAT3 inhibition (STAT3i) or MEK inhibition (MEKi) were established in Ptf1a^cre/+; LSL-Kras^G12D/+ ; and Tgfbr2^flox/flox (PKT) mice and patient-derived xenografts (PDX). Amphiregulin (AREG) levels were determined in serum from human patients with PDAC, LSL-Kras^G12D/+;Trp53^R172H/+;Pdx1^Cre/+ (KPC), and PKT mice. MEKi/STAT3i-treated tumors were analyzed for integrity of the pancreas and the presence of cancer stem cells (CSC). We observed an inverse correlation between ERK and STAT3 phosphorylation. MEKi resulted in an immediate activation of STAT3, whereas STAT3i resulted in TACE-induced, AREG-dependent activation of EGFR and ERK. Combined MEKi/STAT3i sustained blockade of ERK, EGFR, and STAT3 signaling, overcoming resistance to individual MEKi or STAT3i. This combined inhibition attenuated tumor growth in PDX and increased survival of PKT mice while reducing serum AREG levels. Furthermore, MEKi/STAT3i altered the PDAC tumor microenvironment by depleting tumor fibrosis, maintaining pancreatic integrity, and downregulating CD44⁺ and CD133⁺ CSCs. These results demonstrate that resistance to MEKi is mediated through activation of STAT3, whereas TACE-AREG-EGFR-dependent activation of RAS pathway signaling confers resistance to STAT3 inhibition. Combined MEKi/STAT3i overcomes these resistances and provides a novel therapeutic strategy to target the RAS and STAT3 pathway in PDAC.Significance: This report describes an inverse correlation between MEK and STAT3 signaling as key mechanisms of resistance in PDAC and shows that combined inhibition of MEK and STAT3 overcomes this resistance and provides an improved therapeutic strategy to target the RAS pathway in PDAC.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/21/6235/F1.large.jpg Cancer Res; 78(21); 6235-46. ©2018 AACR.

Abstract A46: AdipoRon suppresses ERK and STAT3 to inhibit pancreatic cancer growth

Introduction: The increasing incidence of pancreatic cancer is associated with a rising prevalence of obesity, a documented risk factor for the disease. Obesity harbors a systemic chronic inflammatory disorder characterized by increased production and secretion of pro-inflammatory adipokines leptin, TNF-α, and IL-6; while exhibiting a decrease in the anti-inflammatory adipokine; adiponectin. Dysregulation of these factors is thought to be a key mechanism of obesity associated cancers, contributing to increased activation of mitogenic pathways including PI3K and MAPK. Adiponectin represents an important negative regulator of leptin, TNF-α and IL-6. We previously demonstrated that adiponectin inhibits pancreatic cancer proliferation and tumor growth, however, the molecular mechanisms by which adiponectin regulates these processes are unknown. We hypothesize that Adiponectin Receptor (AdipoR) agonists elicit anti-tumor effects through suppression of RAS-MAPK mediated pathways and its downstream signaling components in pancreatic cancer progression.

Experimental Procedures: The anti-tumor effects of AdipoRon, a novel small molecule agonist of the AdipoR, were assessed in vitro on human (MiaPaca-2 and Panc-1) and murine (P-4313 and K8484) pancreatic cancer cell lines. Cells were treated with AdipoRon in a dose-dependent manner and then assayed for cellular proliferation, apoptosis, colony formation and anchorage-independent growth. The effect of AdipoRon on activation of key RAS-MAPK signaling regulators was investigated by immunoblot analysis. To determine whether AdipoRon could inhibit the effects of obesity associated pro-tumorigenic cytokines, human and mouse pancreatic cancer cells were exposed to plasma collected from obese mice or specifically with recombinant cytokines. To determine whether AdipoRon could inhibit tumor growth in vivo, mice were orthotopically injected in the pancreas with the murine KrasG12D mutant P-4313 cell line. Tumors were allowed to establish for two weeks and treated with either vehicle or AdipoRon. Tumor size and number of Ki67 positive cells were assessed.

Results: Compared to vehicle treatment, in vitro assessment confirmed that AdipoRon was highly effective at inhibiting cell proliferation, increasing apoptosis and preventing colony formation for all pancreatic cell lines tested. Anchorage independent growth was drastically reduced for both Panc1 (3.8 fold) and MiaPaca-2 (5.1 fold) cell lines in the presence of AdipoRon. Treatment of both murine and human pancreatic cancer cell lines with AdipoRon caused a significant dose dependent decrease in pSTAT3, pERK1, and pERK2 with a simultaneous increase in pAMPK. Importantly, AdipoRon completely antagonized the stimulatory effects of obese plasma or recombinant IL-6 on the activation of pSTAT3. Administration of AdipoRon to P-4313 orthotopic pancreatic tumor bearing mice resulted in four fold decrease in tumor size and a 50% reduction in tumor cell proliferation.

Conclusions: AdipoRon, an adiponectin receptor agonist, suppresses KRAS signaling mediators ERK and STAT3 while simultaneously increasing AMPK resulting in inhibition of pancreatic cancer proliferation and tumor growth. Targeting of adiponectin receptors can provide a viable therapeutic strategy for the treatment of pancreatic cancer.

Citation Format: Fanuel Messaggio, Alisha M. Mendonsa, Jason A. Castellanos, Casey Roberts, Nagaraj S. Nagathihalli, Nipun B. Merchant, Lee D. Gorden, Michael N. VanSaun.{Authors}. AdipoRon suppresses ERK and STAT3 to inhibit pancreatic cancer growth. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr A46.

Pancreatic stellate cell secreted IL-6 stimulates STAT3 dependent invasiveness of pancreatic intraepithelial neoplasia and cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is a dynamic tumor supported by several stromal elements such as pancreatic stellate cells (PSC). Significant crosstalk exists between PSCs and tumor cells to stimulate oncogenic signaling and malignant progression of PDAC. However, how PSCs activate intercellular signaling in PDAC cells remains to be elucidated. We have previously shown that activated signal transducer and activator of transcription 3 (STAT3) signaling is a key component in the progression of pancreatic neoplasia. We hypothesize that PSC secreted IL-6 activates STAT3 signaling to promote PanIN progression to PDAC. Human PDAC and mouse PanIN cells were treated with PSC-conditioned media (PSC-CM), and phospho- and total-STAT3 levels by immunoblot analysis were determined. IL-6 was quantified in PSC-CM and cell invasion and colony formation assays were performed in the presence or absence of a neutralizing IL-6 antibody and the JAK/STAT3 inhibitor AZD1480. Serum from Ptf1aCre/+;LSL-KrasG12D/+;Tgfbr2flox/flox (PKT) and LSL-KrasG12D/+; Trp53R172H/+; Pdx1Cre/+ (KPC) mice demonstrated increased levels of IL-6 compared to serum from non-PDAC bearing KC and PK mice. PSC secreted IL-6 activated STAT3 signaling in noninvasive, precursor PanIN cells as well as PDAC cells, resulting in enhanced cell invasion and colony formation in both cell types. There was a significant positive linear correlation between IL-6 concentration and the ratio of phosphorylated STAT3/total STAT3. IL-6 neutralization or STAT3 inhibition attenuated PSC-CM induced activation of STAT3 signaling and tumorigenicity. These data provide evidence that PSCs are directly involved in promoting the progression of PanINs towards invasive carcinoma. This study demonstrates a novel role of PSC secreted IL-6 in transitioning noninvasive pancreatic precursor cells into invasive PDAC through the activation of STAT3 signaling.

Signal Transducer and Activator of Transcription 3, Mediated Remodeling of the Tumor Microenvironment Results in Enhanced Tumor Drug Delivery in a Mouse Model of Pancreatic Cancer

BACKGROUND & AIMS

A hallmark of pancreatic ductal adenocarcinoma (PDAC) is the presence of a dense desmoplastic reaction (stroma) that impedes drug delivery to the tumor. Attempts to deplete the tumor stroma have resulted in formation of more aggressive tumors. We have identified signal transducer and activator of transcription (STAT) 3 as a biomarker of resistance to cytotoxic and molecularly targeted therapy in PDAC. The purpose of this study is to investigate the effects of targeting STAT3 on the PDAC stroma and on therapeutic resistance.

METHODS

Activated STAT3 protein expression was determined in human pancreatic tissues and tumor cell lines. In vivo effects of AZD1480, a JAK/STAT3 inhibitor, gemcitabine or the combination were determined in Ptf1a(cre/+);LSL-Kras(G12D/+);Tgfbr2(flox/flox) (PKT) mice and in orthotopic tumor xenografts. Drug delivery was analyzed by matrix-assisted laser desorption/ionization imaging mass spectrometry. Collagen second harmonic generation imaging quantified tumor collagen alignment and density.

RESULTS

STAT3 activation correlates with decreased survival and advanced tumor stage in patients with PDAC. STAT3 inhibition combined with gemcitabine significantly inhibits tumor growth in both an orthotopic and the PKT mouse model of PDAC. This combined therapy attenuates in vivo expression of SPARC, increases microvessel density, and enhances drug delivery to the tumor without depletion of stromal collagen or hyaluronan. Instead, the PDAC tumors demonstrate vascular normalization, remodeling of the tumor stroma, and down-regulation of cytidine deaminase.

CONCLUSIONS

Targeted inhibition of STAT3 combined with gemcitabine enhances in vivo drug delivery and therapeutic response in PDAC. These effects occur through tumor stromal remodeling and down-regulation of cytidine deaminase without depletion of tumor stromal content.

Abstract 2537: CDK4/6 inhibition synergizes with KRAS-MAPK pathway targeting in pancreatic cancer

Introduction:

Pancreatic ductal adenocarcinoma (PDAC) is one of the most difficult human malignancies to treat due to its innate and acquired therapeutic resistance. Our hypothesis is that cyclin-dependent kinase 4 (CDK4) mediates therapeutic resistance to targeting of the KRAS-MAPK pathway in PDAC.

Experimental Procedure:

We characterized the expression of total and phosphorylated Retinoblastoma (Rb) and MEK protein levels in KRAS wild-type (BxPC3) and KRAS mutant (PANC1, MiaPaca2) human PDAC cell lines at baseline and with MEK and CDK4 inhibition alone or in combination. We then assessed the effects of combined therapy on cell-cycle progression and tumorigenicity (in vitro and in vivo). Finally, using the Ptf1a cre/+;LSL-Kras G12D/+;Tgfbr2 flox/flox (PKT) mouse model of PDAC, we assessed the in vivo overall tumor growth and survival after combined treatment with CDK4/6 and MEK inhibitors.

Results:

Rb functions as a tumor suppressor, and it is inactivated when phosphorylated by CDK4-Cyclin-D1. The CDK4/6 inhibitor (LEE011) effectively inhibits phosphorylation of Rb in cell lines regardless of KRAS mutational status. Combined inhibition of CDK4/6 and MEK (MEK162) decreased phosphorylation of RB and MAPK expression synergistically in the KRAS mutant cell lines, but not the KRAS wild-type BxPC3 cell line. Cell cycle progression was delayed effectively with MEK inhibition alone in the KRAS wild-type cell line, yet only combined CDK4/6 and MEK inhibition effectively delayed cell cycle progression in the KRAS mutant cell lines. Colony formation and invasion were also significantly decreased when Kras mutant cells were treated with combined CDK4/6 and MEK inhibition compared to all monotherapy and control groups. Finally, treatment of PKT mice resulted in a modest increase in OS with MEK inhibition alone, but mice receiving combined CDK4/6 and MEK inhibition exhibited a four-fold increase in OS.

Conclusions:

Combined inhibition of CDK4/6 and MEK results in significantly enhanced therapeutic efficacy and prolonged survival in the aggressive PKT mouse model of PDAC. This study suggests that concurrent inhibition of CDK4/6 and MEK may be an effective treatment for PDAC.

Citation Format: Jason A. Castellanos, Nagaraj Nagathihalli, Michael N. Van Saun, Cameron Kasmai, Yanhua Xiong, Nipun Merchant. CDK4/6 inhibition synergizes with KRAS-MAPK pathway targeting in pancreatic cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2537. doi:10.1158/1538-7445.AM2015-2537

Strategies for Management of Synchronous Colorectal Metastases

The management of synchronous presentation of colorectal cancer and liver metastases has long been a topic of debate and discussion for surgeons due to the unique dilemma of balancing operative timing along with treatment strategy. Operative strategies for resection include staged resection with colon first approach, "reverse" staged resection with liver metastases resected first, and one-stage, or simultaneous, resection of both the primary tumor and liver metastases approach. These operative strategies can be further augmented with perioperative chemotherapy and other novel approaches that may improve resectability and patient survival. The decision on operative timing and approach, however, remains largely dependent on the surgeon's determination of disease resectability, patient fitness, and the need for neoadjuvant chemotherapy.

Intensity of follow-up after pancreatic cancer resection

The prognosis of patients diagnosed with pancreatic adenocarcinoma remains dismal. Of the 15-20 % of patients who are candidates for potentially curative resection, 66-92 % will develop recurrent disease. Although guidelines for surveillance in the postoperative setting exist, they are not evidence based, and there is wide variability of strategies utilized. Current surveillance guidelines as suggested by the National Comprehensive Cancer Network (NCCN) include routine history and physical, measurement of serum cancer-associated antigen 19-9 (CA19-9) levels, and computed tomographic imaging at 3- to 6-month intervals for the first 2 years, and annually thereafter. However, the lack of prospective clinical data examining the efficacy of different surveillance strategies has led to a variability of the intensity of follow-up and a lack of consensus on its necessity and efficacy. Recent therapeutic advances may have the potential to significantly alter survival after recurrence, but a careful consideration of current surveillance strategies should be undertaken to optimize existing approaches in the face of high recurrence and low survival rates.

Emerging targets in pancreatic cancer: epithelial-mesenchymal transition and cancer stem cells

Pancreatic ductal adenocarcinoma is one of the most aggressive solid malignancies and is characterized by poor response to current therapy and a dismal survival rate. Recent insights regarding the role of cancer stem cells (CSCs) and epithelial–mesenchymal transition (EMT) in tumorigenesis have brought further understanding to the field and have highlighted new therapeutic targets. CSCs are a distinct subset of cancer cells, with the ability to differentiate into other cell types and self-renew in order to fuel the maintenance of tumor amplification. Transition of a cancer cell from an EMT leads to increased migratory and invasive properties, and thus facilitates initiation of metastasis. EMT is regulated by a complex network of factors that includes cytokines, growth factors, aberrant signaling pathways, transcription factors, and the tumor microenvironment. There is emerging evidence that the EMT process may give rise to CSCs, or at least cells with stem cell-like properties. We review the key pathways involved in both of these processes, the biomarkers used to identify CSCs, and new therapeutic approaches targeting CSCs and EMT in pancreatic ductal adenocarcinoma.