Tumour response to TRK inhibition in a patient with pancreatic adenocarcinoma harbouring an NTRK gene fusion

Design, synthesis, and biological evaluation of 2,6,7-substituted pyrrolo[2,3-d]pyrimidines as cyclin dependent kinase inhibitor in pancreatic cancer cells

Pancreatic cancer is a highly malignant tumor, and more effective treatment is urgently needed to lengthen the life of patients. In this paper a class of new 2,6,7-substituted pyrrolo[2,3-d]pyrimidine derivatives of CDK 4/6 inhibitor ribociclib (1) was designed and synthesized to investigate their effect on the proliferation of pancreatic cancer cells. The structure-activity relationship (SAR) of synthetic compounds was analyzed based on both their in vitro anti-proliferative activity and the CDK4 inhibitory activity. A series of 6-anilinocarbonyl-substituted pyrrolo[2,3-d]pyrimidine derivatives (25, 41-48) showed the significantly increased potency against two proliferating cancer cell lines (MIA PaCa-2 and BxPC-3) in MTT assay though their CDK4 inhibitory activity were lower in a varying range compared to 1. The most potent compound 41 was identified as a highly selective and potent CDK 4/6 inhibitor in the human kinases profiling assay, it also exhibited the favorable in vitro pharmacokinetic properties for further in vivo evaluation. Meanwhile, 41 exhibited the potential as a combination partner with mTOR inhibitor to treat pancreatic cancer. Alternatively, introducing of sulfonamide fragment into C2-substituent of pyrrolo[2,3-d]pyrimidine provided the clue for future optimization to afford new CDK9 inhibitors.

The genetics of ductal adenocarcinoma of the pancreas in the year 2020: dramatic progress, but far to go

The publication of the "Pan-Cancer Atlas" by the Pan-Cancer Analysis of Whole Genomes Consortium, a partnership formed by The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC), provides a wonderful opportunity to reflect on where we stand in our understanding of the genetics of pancreatic cancer, as well as on the opportunities to translate this understanding to patient care. From germline variants that predispose to the development of pancreatic cancer, to somatic mutations that are therapeutically targetable, genetics is now providing hope, where there once was no hope, for those diagnosed with pancreatic cancer.

Overexpression of rhophilin 2 promotes pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the most common type of pancreatic cancer and is the seventh leading cause of global cancer deaths. In recent years, targeted therapy has been used for pancreatic cancer; however, the drugs available for use in targeted therapy for pancreatic cancer are still very limited. Hence, identification of novel targeted molecules for PDAC is required. Rhophilin 2 (RHPN2) was proven to be a driver gene in glioblastoma. However, the function of RHPN2 in PDAC remains unknown. In the present study, the function of RHPN2 was investigated. The RHPN2 levels were overexpressed by pcDNA3.1-RHPN2 and downregulated by si-RHPN2. Cell proliferation was assessed using the MTT assay and apoptosis was assessed using flow cytometry. The results revealed that high RHPN2 levels in PDAC tissue were correlated with a low overall survival rate of patients with PDAC. Inhibition of RHPN2 reduced SW1990 and PANC1 proliferation and increased the rate of apoptosis. Network analysis demonstrated that centrosomal protein 78 expression was negatively correlated with RHPN2 expression. In conclusion, the present study demonstrated that RHPN2 may promote PDAC making it a potential candidate for targeted therapy.

Advances in Regulating Tumorigenicity and Metastasis of Cancer Through TrkB Signaling

The clinical pathology of various human malignancies is supported by tropomyosin receptor kinase (Trk) B TrkB which is a specific binding receptor of the brain-derived neurotrophic factor (BDNF). TrkB and TrkB fusion proteins have been observed to be over-expressed in many cancer patients. Moreover, these proteins have been observed in multiple types of cells. A few signaling pathways can be modulated by the abnormal activation of the BDNF/TrkB pathway. These signaling pathways include PI3K/Akt pathway, transactivation of EGFR, phospholipase C-gamma (PLCγ) pathway, Ras-Raf-MEK-ERK pathway, Jak/STAT pathway, and nuclear factor kappalight- chain-enhancer of activated B cells (NF-kB) pathway. The BDNF/TrkB pathway, when overexpressed in tumors, is correlated with reduced clinical prognosis and short survival time of patients. Targeting the BDNF/TrkB pathway and the use of Trk inhibitors, such as entrectinib, larotrectinib, etc. are promising methods for targeted therapy of tumors. The present review provides an overview of the role of the TrkB pathway in the pathogenesis of cancer and its value as a potential therapeutic target.

The Immune Microenvironment in Pancreatic Cancer

The biology of solid tumors is strongly determined by the interactions of cancer cells with their surrounding microenvironment. In this regard, pancreatic cancer (pancreatic ductal adenocarcinoma, PDAC) represents a paradigmatic example for the multitude of possible tumor-stroma interactions. PDAC has proven particularly refractory to novel immunotherapies, which is a fact that is mediated by a unique assemblage of various immune cells creating a strongly immunosuppressive environment in which this cancer type thrives. In this review, we outline currently available knowledge on the cross-talk between tumor cells and the cellular immune microenvironment, highlighting the physiological and pathological cellular interactions, as well as the resulting therapeutic approaches derived thereof. Hopefully a better understanding of the complex tumor-stroma interactions will one day lead to a significant advancement in patient care.

Pancreatic Adenocarcinoma: Unconventional Approaches for an Unconventional Disease

This review highlights current treatments, limitations, and pitfalls in the management of pancreatic cancer and discusses current research in novel targets and drug development to overcome these clinical challenges. We begin with a review of the clinical landscape of pancreatic cancer, including genetic and environmental risk factors, as well as limitations in disease diagnosis and prevention. We next discuss current treatment paradigms for pancreatic cancer and the shortcomings of targeted therapy in this disease. Targeting major driver mutations in pancreatic cancer, such as dysregulation in the KRAS and TGFβ signaling pathways, have failed to improve survival outcomes compared with nontargeted chemotherapy; thus, we describe new advances in therapy such as Ras-binding pocket inhibitors. We then review next-generation approaches in nanomedicine and drug delivery, focusing on preclinical advancements in novel optical probes, antibodies, small-molecule agents, and nucleic acids to improve surgical outcomes in resectable disease, augment current therapies, expand druggable targets, and minimize morbidity. We conclude by summarizing progress in current research, identifying areas for future exploration in drug development and nanotechnology, and discussing future prospects for management of this disease.

Inhibition of MEK1/2 Forestalls the Onset of Acquired Resistance to Entrectinib in Multiple Models of NTRK1-Driven Cancer

NTRK1 gene fusions are actionable drivers of numerous human malignancies. Here, we show that expression of the TPR-NTRK1 fusion kinase in immortalized mouse pancreatic ductal epithelial (IMPE) (pancreas) or mouse lung epithelial (MLE-12) cells is sufficient to promote rapidly growing tumors in mice. Both tumor models are exquisitely sensitive to targeted inhibition with entrectinib, a tropomyosin-related kinase A (TRKA) inhibitor. Initial regression of NTRK1-driven tumors is driven by induced expression of BIM, such that BIM silencing leads to a diminished response to entrectinib in vivo. However, the emergence of drug-resistant disease limits the long-term durability of responses. Based on the reactivation of RAF>MEK>ERK signaling observed in entrectinib-treated tumors, we show that the combination of entrectinib plus the MEK1/2 inhibitor cobimetinib dramatically forestalls the onset of drug resistance in vivo. Collectively, these data provide a mechanistic rationale for rapid clinical deployment of combined inhibition of TRKA plus MEK1/2 in NTRK1-driven cancers.

Advanced Pancreatic Ductal Adenocarcinoma: Moving Forward

Globally, the death rate of pancreatic ductal adenocarcinoma (PDAC) has doubled over 30 years and is likely to further increase, making PDAC a leading cause of cancer-related death in the coming years. PDAC is typically diagnosed at an advanced stage, and modified FOLFIRINOX or nab-paclitaxel and gemcitabine are the mainstay of systemic therapy. For elderly patients with good performance status, low-dose treatment can preserve quality of life without compromising cancer control or survival. Maintenance therapy should be considered in PDAC patients achieving disease control with systemic therapy. In particular, olaparib has demonstrated a progression-free survival benefit of 3.6 months in a subgroup of PDAC patients with germline BRCA1/2 mutations (ca. 10% of all PDAC). Pancreatic enzyme replacement therapy is often omitted in the treatment of patients with PDAC, with possibly deleterious consequences. Small intestinal bacterial overgrowth is highly prevalent in patients with PDAC and should be considered in the diagnostic algorithm of PDAC patients with bloating and diarrhea. Rivaroxaban has been associated with a reduced risk of thrombosis without an increase in major bleeding events, and its use should be considered in every patient with advanced PDAC undergoing systemic therapy.

Primary Resistance to Brigatinib in a Patient with Lung Adenocarcinoma Harboring ALK G1202R Mutation and LIPI-NTRK1 Rearrangement

Purpose

Anaplastic lymphoma kinase (ALK) inhibitors have transformed the management of non-small-cell lung cancer (NSCLC) patients with ALK gene rearrangement. This paper reports a new resistance mechanism to a second-generation ALK inhibitor, brigatinib.

Case Report

A 43-year-old woman who had no history of smoking was diagnosed with stage IVa (T2bN2M1b) lung adenocarcinoma. After the first-line chemotherapy failed, the patient received crizotinib due to the presence of EML4-ALK fusion by next-generation sequencing (NGS). The patient had disease progression after 8 months on crizotinib, and a second NGS identified the ALK G1202R resistance mutation. Therefore, she was switched to brigatinib. After only 53 days of treatment with brigatinib, the patient developed a new 1.6×1.2 cm lesion in the mediastinal lymph node. A third NGS testing revealed a new form of NTRK rearrangement (LIPI-NTRK1). The patient died 16 months after diagnosis.

Conclusion

This paper provides new insights into the primary resistance to brigatinib in NSCLC patients carrying ALK G1202R mutation. The new fusion form of NTRK rearrangement was detected, which may provide potential treatment options after brigatinib resistance.

Negative prognostic impact of PD-L1 expression in tumor cells of undifferentiated (anaplastic) carcinoma with osteoclast-like giant cells of the pancreas: study of 13 cases comparing ductal pancreatic carcinoma and review of the literature

Pancreatic carcinoma remains one of the leading cancer-related causes of death worldwide and is generally characterized by a dismal prognosis and limited potential for oncologic treatment. A rare subvariant of pancreatic cancer, undifferentiated carcinoma with osteoclast-like giant cells (UCOGC), has an unpredictable prognosis according to many previous studies, with unexpectedly long survival in individual cases. In this study, we collected, retrospectively, 13 cases of well-documented UCOGCs and performed immunohistochemistry focused on the expression of the programmed death-ligand 1 (PD-L1) and several other potential therapeutic and predictive markers (PanTRK, p53, MSH2, PMS2, and the number of tumor-infiltrating lymphocytes), to explore their correlation with the follow-up of the patients. As a control group, we examined 24 cases of conventional pancreatic ductal adenocarcinoma (PDAC). In our results, PanTRK was negative in all 24 cases. P53 did not show any significant differences between UCOGCs and PDACs, and the entire cohort was MSH2, MLH1, PMS2, and MSH6 positive. Significant differences were present in the analysis of PD-L1: UCOGCs were found to express PD-L1 significantly more frequently and have a higher number of tumor-infiltrating lymphocytes than PDAC. The expression of PD-L1 was related to significantly shorter survival in patients with UCOGC and in the entire cohort. Patients with PD-L1 negative UCOGCs displayed surprisingly long survival in comparison to PD-L1 positive UCOGCs and PDACs (both PD-L1+ and PD-L1-). We compared our results with previously published data, and, after statistical analysis, we were able to identify PD-L1 as an effective prognostic marker of UCOGC and suggest a strong need for a clinical trial of immune checkpoint immunotherapy in patients with advanced PD-L1 positive UCOGC.

New Treatment Strategies for Metastatic Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is typically diagnosed at an advanced stage, with systemic therapy being the mainstay of treatment. Survival continues to be limited, typically less than 1 year. The PDAC microenvironment is characterized by a paucity of malignant epithelial cells, abundant stroma with predominantly immunosuppressive T cells and myelosuppressive-type macrophages (M2), and hypovascularity. The current treatment options for metastatic PDAC are modified (m)FOLFIRINOX /FOLFIRINOX or nab-paclitaxel and gemcitabine in patients with good performance status (PS) (ECOG 0-1/KPS 70-100%) and gemcitabine with or without a second agent for those with ECOG PS 2-3. New therapies are emerging, and the current guidelines endorse both germline and somatic testing in PDAC to evaluate actionable findings. Important themes related to new therapeutic approaches include DNA damage repair strategies, immunotherapy, targeting the stroma, and cancer-cell metabolism. Targeted therapy alone (outside small genomically defined subsets) or in combination with standard cytotoxic therapy, thus far, has proven disappointing in PDAC; however, novel therapies are evolving with increased integration of genomic profiling along with a better understanding of the tumor microenvironment and immunology. A small but important sub-group of patients have some of these agents available in the clinics for use. Olaparib was recently approved by the US Food and Drug Administration for maintenance therapy in germline BRCA1/2 mutated PDAC following demonstration of survival benefit in a phase 3 trial. Pembrolizumab is approved for patients with defects in mismatch repair/microsatellite instability. PDAC with wild-type KRAS represents a unique subgroup who have enrichment of potentially targetable oncogenic drivers. Small-molecule inhibitors including ERBB inhibitors (e.g., afatinib, MCLA-128), TRK inhibitors (e.g., larotrectinib, entrectinib), ALK/ROS inhibitor (e.g., crizotinib), and BRAF/MEK inhibitors are in development. In a small subset of patients with the KRASG12C mutation, a KRASG12C inhibitor, AMG510, and other agents are being investigated. Major efforts are underway to effectively target the tumor microenvironment and to integrate immunotherapy into the treatment of PDAC, and although thus far the impact has been modest to ineffective, nonetheless, there is optimism that some of the challenges will be overcome.

Pancreatic Cancer Molecular Classifications: From Bulk Genomics to Single Cell Analysis

Pancreatic cancer represents one of the most lethal disease worldwide but still orphan of a molecularly driven therapeutic approach, although many genomic and transcriptomic classifications have been proposed over the years. Clinical heterogeneity is a hallmark of this disease, as different patients show different responses to the same therapeutic regimens. However, genomic analyses revealed quite a homogeneous disease picture, with very common mutations in four genes only (KRAS, TP53, CDKN2A, and SMAD4) and a long tail of other mutated genes, with doubtful pathogenic meaning. Even bulk transcriptomic classifications could not resolve this great heterogeneity, as many informations related to small cell populations within cancer tissue could be lost. At the same time, single cell analysis has emerged as a powerful tool to dissect intratumoral heterogeneity like never before, with possibility of generating a new disease taxonomy at unprecedented molecular resolution. In this review, we summarize the most relevant genomic, bulk and single-cell transcriptomic classifications of pancreatic cancer, and try to understand how novel technologies, like single cell analysis, could lead to novel therapeutic strategies for this highly lethal disease.