Present status and problems on molecular targeted therapy of cancer

Revolutionizing in vivo therapy with CRISPR/Cas genome editing: breakthroughs, opportunities and challenges

Genome editing using the CRISPR/Cas system has revolutionized the field of genetic engineering, offering unprecedented opportunities for therapeutic applications in vivo. Despite the numerous ongoing clinical trials focusing on ex vivo genome editing, recent studies emphasize the therapeutic promise of in vivo gene editing using CRISPR/Cas technology. However, it is worth noting that the complete attainment of the inherent capabilities of in vivo therapy in humans is yet to be accomplished. Before the full realization of in vivo therapeutic potential, it is crucial to achieve enhanced specificity in selectively targeting defective cells while minimizing harm to healthy cells. This review examines emerging studies, focusing on CRISPR/Cas-based pre-clinical and clinical trials for innovative therapeutic approaches for a wide range of diseases. Furthermore, we emphasize targeting cancer-specific sequences target in genes associated with tumors, shedding light on the diverse strategies employed in cancer treatment. We highlight the various challenges associated with in vivo CRISPR/Cas-based cancer therapy and explore their prospective clinical translatability and the strategies employed to overcome these obstacles.

Combining PARP Inhibition with Platinum, Ruthenium or Gold Complexes for Cancer Therapy

Platinum drugs are heavily used first-line chemotherapeutic agents for many solid tumours and have stimulated substantial interest in the biological activity of DNA-binding metal complexes. These complexes generate DNA lesions which trigger the activation of DNA damage response (DDR) pathways that are essential to maintain genomic integrity. Cancer cells exploit this intrinsic DNA repair network to counteract many types of chemotherapies. Now, advances in the molecular biology of cancer has paved the way for the combination of DDR inhibitors such as poly (ADP-ribose) polymerase (PARP) inhibitors (PARPi) and agents that induce high levels of DNA replication stress or single-strand break damage for synergistic cancer cell killing. In this review, we summarise early-stage, preclinical and clinical findings exploring platinum and emerging ruthenium anti-cancer complexes alongside PARPi in combination therapy for cancer and also describe emerging work on the ability of ruthenium and gold complexes to directly inhibit PARP activity.

Aromatic Linkers Unleash the Antiproliferative Potential of 3-Chloropiperidines Against Pancreatic Cancer Cells

In this study, we describe the synthesis and biological evaluation of a set of bis-3-chloropiperidines (B-CePs) containing rigid aromatic linker structures. A modification of the synthetic strategy also enabled the synthesis of a pilot tris-3-chloropiperidine (Tri-CeP) bearing three reactive meta-chloropiperidine moieties on the aromatic scaffold. A structure-reactivity relationship analysis of B-CePs suggests that the arrangement of the reactive units affects the DNA alkylating activity, while also revealing correlations between the electron density of the aromatic system and the reactivity with biologically relevant nucleophiles, both on isolated DNA and in cancer cells. Interestingly, all aromatic 3-chloropiperidines exhibited a marked cytotoxicity and tropism for 2D and 3D cultures of pancreatic cancer cells. Therefore, the new aromatic 3-chloropiperidines appear to be promising contenders for further development of mustard-based anticancer agents aimed at pancreatic cancers.

Pleuromutilin Inhibits Proliferation and Migration of A2780 and Caov-3 Ovarian Carcinoma Cells and Growth of Mouse A2780 Tumor Xenografts by Down-Regulation of pFAK2

BACKGROUND Pleuromutilin is a natural tricyclic, derived from the fungus, Pleurotus mutilus. This study aimed to investigate the effects of pleuromutilin on migration and proliferation of A2780 and Caov-3 human ovarian carcinoma cells and the growth of A2780 tumor xenografts in mice and the molecular mechanisms involved. MATERIAL AND METHODS A2780 and Caov-3 human ovarian carcinoma cells were cultured with and without 40, 160, and 200 μM of pleuromutilin. The Edu fluorescence assay, the wound-healing assay, and Matrigel were used to measure A2780 and Caov-3 cell proliferation, migration, invasion, and adhesion in vitro, respectively. Western blot measured protein levels of FAK, p-FAK, MMP-2, and MMP-9. A2780 cells were injected subcutaneously into mice to determine the effects of pleuromutilin on the growth of tumor xenografts. RESULTS Pleuromutilin significantly reduced A2780 and Caov-3 cell proliferation at 48 h in a dose-dependent manner (P<0.05), and at 200 μM, pleuromutilin reduced cell proliferation by 21.43% and 23.65%, respectively. Treatment of A2780 cells with pleuromutilin significantly reduced cell migration, invasion, and adhesion and the expression of p-FAK, MMP-2, and MMP-9 compared with untreated controls. In the mouse tumor xenograft model, treatment with pleuromutilin significantly reduced tumor size compared with the untreated group and inhibited tumor metastasis to the intestine, spleen, and peritoneal cavity. CONCLUSIONS In A2780 and Caov-3 human ovarian carcinoma cells, pleuromutilin inhibited cell proliferation, migration, invasion, and adhesion in a dose-dependent manner, and reduced tumor growth and metastases in a mouse A2780 cell tumor xenograft model.

Olaparib tablets for the treatment of germ line BRCA-mutated metastatic breast cancer

INTRODUCTION

Germ line BRCA mutations (gBRCAm) are diagnosed in approximately 5% of unselected breast cancer patients. Olaparib is a new treatment option for patients with a gBRCAm who have metastatic HER2-negative breast cancer. Areas covered: Olaparib is an oral poly (ADP-ribose) polymerase inhibitor that has been shown in phase I-III clinical trials to have single-agent efficacy in breast cancer patients with gBRCAm. The recent phase III OlympiAD study demonstrated a statistically significant progression-free survival benefit compared with the chemotherapy control arm, although an overall survival benefit has not been demonstrated. The most common adverse events seen with olaparib include nausea, anemia, and vomiting. The most common grade 3 adverse events are anemia and neutropenia. Expert commentary: The US FDA-approved olaparib tablets in January 2018 for the treatment of patients with a gBRCAm and metastatic HER2-negative breast cancer. This is a well-tolerated and effective treatment option for this patient population, particularly in patients with triple-negative breast cancer in which chemotherapy is the only alternative. More data are needed to understand the role of olaparib in combination with endocrine therapy, other targeted agents, and chemotherapy, as well as sequentially with platinum chemotherapy in the metastatic setting.

Conceptual frameworks of synthetic lethality in clear cell carcinoma of the ovary

Targeting non-oncogenes may result in the selective death of cancer cells. Clear cell carcinoma of the ovary (CCC) may exhibit resistance against conventional chemotherapy and is associated with poor prognosis. The aim of the present report was to review synthetic lethality-based therapies for CCC. Previous English-language studies were reviewed to accumulate preclinical and clinical data on targeting synthetic lethal partners. Synthetic lethal interactions have a variety of types, involving components of a backup or parallel pathway with overlapping functions, components encoded by paralogous pairs, subunit components that form heteromeric complexes and components that are arranged in a single linear pathway. A set of candidate gene targets potentially resulting in synthetic lethality have been previously identified. HNF class homeobox, AT-rich interaction domain 1A, ATR serine/threonine kinase, ATM serine/threonine kinase, checkpoint kinase 1 and phosphatase and tensin homolog may be the key partner genes. A variety of loss of function genes in CCC are driver or passenger events and may function as synthetic lethal pairs under replication stress conditions. Further clinical studies will be required to investigate the safety and therapeutic effect of synthetic lethality pairs in CCC tumor types with replication stress.

Ligand-Independent Epidermal Growth Factor Receptor Overexpression Correlates with Poor Prognosis in Colorectal Cancer

Purpose

Molecular treatments targeting epidermal growth factor receptors (EGFRs) are important strategies for advanced colorectal cancer (CRC). However, clinicopathologic implications of EGFRs and EGFR ligand signaling have not been fully evaluated. We evaluated the expression of EGFR ligands and correlation with their receptors, clinicopathologic factors, and patients’ survival with CRC.

Materials and Methods

The expression of EGFR ligands, including heparin binding epidermal growth factor-like growth factor (HBEGF), transforming growth factor (TGF), betacellulin, and epidermal growth factor (EGF), were evaluated in 331 consecutive CRC samples using mRNA in situ hybridization (ISH). We also evaluated the expression status of EGFR, human epidermal growth factor receptor 2 (HER2), HER3, and HER4 using immunohistochemistry and/or silver ISH.

Results

Unlike low incidences of TGF (38.1%), betacellulin (7.9%), and EGF (2.1%), HBEGF expression was noted in 62.2% of CRC samples. However, the expression of each EGFR ligand did not reveal significant correlations with survival. The combined analyses of EGFR ligands and EGFR expression indicated that the ligands‒/EGFR+ group showed a significant association with the worst disease-free survival (DFS; p=0.018) and overall survival (OS; p=0.005). It was also an independent, unfavorable prognostic factor for DFS (p=0.026) and OS (p=0.007). Additionally, HER4 nuclear expression, regardless of ligand expression, was an independent, favorable prognostic factor for DFS (p=0.034) and OS (p=0.049), by multivariate analysis.

Conclusion

Ligand-independent EGFR overexpression was suggested to have a significant prognostic impact; thus, the expression status of EGFR ligands, in addition to EGFR, might be necessary for predicting patients' outcome in CRC.

Metabolic stress induces a Wnt-dependent cancer stem cell-like state transition

Reciprocal interactions between cancer cells and the tumor microenvironment drive multiple clinically significant behaviors including dormancy, invasion, and metastasis as well as therapy resistance. These microenvironment-dependent phenotypes share typical characteristics with cancer stem cells (CSC). However, it is poorly understood how metabolic stress in the confined tumor microenvironment contributes to the emergence and maintenance of CSC-like phenotypes. Here, we demonstrate that chronic metabolic stress (CMS) in a long-term nutrient deprivation induces a Wnt-dependent phenoconversion of non-stem cancer cells toward stem-like state and this is reflected in the transcriptome analysis. Addition of Wnt3a as well as transfection of dominant-negative Tcf4 establishes an obligatory role for the Wnt pathway in the acquisition of CSC-like characteristics in response to metabolic stress. Furthermore, systematic characterization for multiple single cell-derived clones and negative enrichment of CD44+/ESA+ stem-like cancer cells, all of which recapitulate stem-like cancer characteristics, suggest stochastic adaptation rather than selection of pre-existing subclones. Finally, CMS in the tumor microenvironment can drive a CSC-like phenoconversion of non-stem cancer cells through stochastic state transition dependent on the Wnt pathway. These findings contribute to an understanding of the metabolic stress-driven dynamic transition of non-stem cancer cells to a stem-like state in the tumor metabolic microenvironment.

Comprehensive analysis of RET and ROS1 rearrangement in lung adenocarcinoma

The success of crizotinib in ALK-positive patients has elicited efforts to find new oncogenic fusions in lung cancer. These efforts have led to the discovery of novel oncogenic fusion genes such as ROS1 and RET. However, the molecular and clinicopathologic characteristics associated with RET or ROS1 fusion, compared with ALK fusion-positive lung cancer, remain unclear. We accordingly analyzed the clinicopathologic characteristics of RET- and ROS1-fusion-positive lung adenocarcinomas. We further performed immunohistochemistry and fluorescence in situ hybridization analysis (FISH) in 15 cases of RET and 9 cases of ROS1 fusion tumors by identified NanoString's nCounter screening. RET fusion-positive patients were younger in age, never-smokers, and in early T stage; ROS1 fusion-positive patients had a higher number of never-smokers compared with patients with quintuple-negative (EGFR-/KRAS-/ALK-/ROS1-/RET-) lung adenocarcinoma. Histologically, RET and ROS1 fusion tumors share the solid signet-ring cell and mucinous cribriform pattern, as previously mentioned in the histology of ALK fusion tumors. Therefore, it can be presumed that fusion gene-associated lung adenocarcinomas share similar histologic features. In immunohistochemistry, the majority of 15 RET and 9 ROS1 fusion-positive cases showed positivity of more than moderate intensity and cytoplasmic staining for RET and ROS1 proteins, respectively. In FISH, the majority of RET and ROS1 rearrangement showed two signal patterns such as one fusion signal and two separated green and orange signals (1F1G1O) and an isolated 3' green signal pattern (1F1G). Our study has provided not only characteristics of fusion gene-associated histologic features but also a proposal for a future screening strategy that will enable clinicians to select cases needed to be checked for ROS1 and RET rearrangements based on clinicohistologic features.

Influence of ribosomal protein L39-L in the drug resistance mechanisms of lacrimal gland adenoid cystic carcinoma cells

BACKGROUND

Cancer constitutes a key pressure on public health regardless of the economy state in different countries. As a kind of highly malignant epithelial tumor, lacrimal gland adenoid cystic carcinoma can occur in any part of the body, such as salivary gland, submandibular gland, trachea, lung, breast, skin and lacrimal gland. Chemotherapy is one of the key treatment techniques, but drug resistance, especially MDR, seriously blunts its effects. As an element of the 60S large ribosomal subunit, the ribosomal protein L39-L gene appears to be documented specifically in the human testis and many human cancer samples of different origins.

MATERIALS AND METHODS

Total RNA of cultured drug-resistant and susceptible lacrimal gland adenoid cystic carcinoma cells was seperated, and real time quantitative RT-PCR were used to reveal transcription differences between amycin resistant and susceptible strains of lacrimal gland adenoid cystic carcinoma cells. Viability assays were used to present the amycin resistance difference in a RPL39-L transfected lacrimal gland adenoid cystic carcinoma cell line as compared to control vector and null-transfected lacrimal gland adenoid cystic carcinoma cell lines.

RESULTS

The ribosomal protein L39-L transcription level was 6.5-fold higher in the drug-resistant human lacrimal gland adenoid cystic carcinoma cell line than in the susceptible cell line by quantitative RT-PCR analysis. The ribosomal protein L39-L transfected cells revealed enhanced drug resistance compared to plasmid vector-transfected or null-transfected cells as determined by methyl tritiated thymidine (3H-TdR) incorporation.

CONCLUSIONS

The ribosomal protein L39-L gene could possibly have influence on the drug resistance mechanism of lacrimal gland adenoid cystic carcinoma cells.

Beyond angiogenesis blockade: targeted therapy for advanced cervical cancer

The global burden of advanced stage cervical cancer remains significant, particular in resource poor countries where effective screening programs are absent. Unfortunately, a proportion of patients will be diagnosed with advanced stage disease, and may suffer from persistent or recurrent disease despite treatment with combination chemotherapy and radiation. Patients with recurrent disease have a poor salvage rate, with an expected 5-year survival of less than 10%. Recently, significant gains have been made in the antiangiogenic arena; nonetheless the need to develop effective alternate targeted strategies is implicit. As such, a review of molecular targeted therapy in the treatment of this disease is warranted. In an era of biologics, combined therapy with cytotoxic drugs and molecular targeted agents, represents an exciting arena yet to be fully explored.

PARP inhibition and synthetic lethality in ovarian cancer

Ovarian cancer is the leading cause of gynecologic cancer death in women. Our understanding of the treatment of ovarian cancer has evolved over the last decade, with the use neo-adjuvant chemotherapy, combined intravenous-intraperitoneal (IV-IP) chemotherapy, as well as dose dense paclitaxel. Despite significant improvements in overall survival, the majority of patients succumb to recurrent chemotherapy resistant disease. Given the above, an emphasis has been placed on exploring alternate therapeutics. Recent research efforts have improved our understanding of the molecular biology of ovarian cancer and novel targeted treatment strategies have emerged. With the discovery of BRCA1 and BRCA2 gene mutations, and a more comprehensive assessment of heredity ovarian cancer syndrome, targeted interventions exploiting this biologic susceptibility have emerged. To date, the most studied of these have been PARP inhibitors. The purpose of this review will be to discuss PARP inhibition in advanced stage ovarian cancer, highlighting recent scientific advancements.

Personalized oncology in interventional radiology

As personalized medicine becomes more applicable to oncologic practice, image-guided biopsies will be integral for enabling predictive and pharmacodynamic molecular pathology. Interventional radiology has a key role in defining patient-specific management. Advances in diagnostic techniques, genomics, and proteomics enable a window into subcellular mechanisms driving hyperproliferation, metastatic capabilities, and tumor angiogenesis. A new era of personalized medicine has evolved whereby clinical decisions are adjusted according to a patient's molecular profile. Several mutations and key markers already have been introduced into standard oncologic practice. A broader understanding of personalized oncology will help interventionalists play a greater role in therapy selection and discovery.

Multiparametric PET/CT-perfusion does not add significant additional information for initial staging in lung cancer compared with standard PET/CT

BACKGROUND

The purpose of this study was to assess the relationship of CT-perfusion (CTP), 18F-FDG-PET/CT and histological parameters, and the possible added value of CTP to FDG-PET/CT in the initial staging of lung cancer.

METHODS

Fifty-four consecutive patients (median age 65 years, 15 females, 39 males) with suspected lung cancer were evaluated prospectively by CT-perfusion scan and 18F-FDG-PET/CT scan. Overall, 46 tumors were identified. CTP parameters blood flow (BF), blood volume (BV), and mean transit time (MTT) of the tumor tissue were calculated. Intratumoral microvessel density (MVD) was assessed quantitatively. Differences in CTP parameters concerning tumor type, location, PET positivity of lymph nodes, TNM status, and UICC stage were analyzed. Spearman correlation analyses between CTP and 18F-FDG-PET/CT parameters (SUVmax, SUVmean, PETvol, and TLG), MVD, tumor size, and tumor stage were performed.

RESULTS

The mean BF (mL/100 mL min-1), BV (mL/100 mL), and MTT (s) was 35.5, 8.4, and 14.2, respectively. The BF and BV were lower in tumors with PET-positive lymph nodes (p = 0.02). However, the CTP values were not significantly different among the N stages. The CTP values were not different, depending on tumor size and location. No significant correlation was found between CTP parameters and MVD.

CONCLUSIONS

Overall, the CTP information showed only little additional information for the initial staging compared with standard FDG-PET/CT. Low perfusion in lung tumors might possibly be associated with metabolically active regional lymph nodes. Apart from that, both CTP and 18F-FDG-PET/CT parameter sets may reflect different pathophysiological mechanisms in lung cancer.

Activation of ERK1/2 and Akt is associated with cisplatin resistance in human lung cancer cells

Cisplatin is widely used for the treatment of solid tumours including small cell lung cancers, but its success is often compromised by relapse and resistance to further treatment. Extracellular signal-regulated kinase 1/2 (ERK1/2) and Akt are two major cell survival pathways that are upregulated and activated in lung cancer tissues. Phosphorylated ERK1/2 (p-ERK1/2) and Akt (p-Akt) can be further stimulated by chemotherapeutics in cancer cells. Although individually targeting the ERK1/2 or Akt pathway has been reported to sensitize cancer cells to therapy, the effect of concurrently blocking these two pathways on the sensitivity of lung cancer cells to cisplatin has not been investigated. In the present study, we aimed to determine whether the ERK1/2 and Akt pathways contribute to cisplatin resistance in human small cell lung cancer A549 cells. The results showed that cisplatin activates p-ERK1/2 and p-Akt in A549 cells. Blockade of either of these pathways with chemical inhibitors moderately sensitized A549 cells to cisplatin-induced apoptosis and reduced cell viability. Strikingly, concurrent inhibition of p-ERK1/2 and p-Akt significantly potentiated cisplatin cytotoxicity in vitro and in vivo. The sensitization of A549 cells to cisplatin cytotoxicity induced by p-Akt inhibition was mediated by the upregulation of PUMA, whereas that induced by p-ERK1/2 inhibition occurred by Bcl-2 downregulation. These data indicate that the cooperative effects of p-ERK1/2 and p-Akt on attenuating cisplatin cytotoxicity are mediated by PUMA and Bcl-2 regulation, and concurrently blocking these pathways may be an effective strategy for improving the efficacy of cisplatin as anticancer treatment.

Treatment of Non-small Cell Lung Carcinoma after Failure of Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor

Since the first description of non-small cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutation as a distinct clinical entity, studies have proved EGFR tyrosine kinase inhibitors (TKIs) as a first choice of treatment. The median response duration of TKIs as a first-line treatment for EGFR mutant tumors ranges from 11 to 14 months. However, acquired resistance to EGFR-TKIs is inevitable due to various mechanisms, such as T790M, c-Met amplification, activation of alternative pathways (IGF-1, HGF, PI3CA, AXL), transformation to mesenchymal cell or small cell features, and tumor heterogeneity. Until development of a successful treatment strategy to overcome such acquired resistance, few options are currently available. Here we provide a summary of the therapeutic options after failure of first line EGFR-TKI treatment for NSCLC.

Personalized Medicine

Human differences in disease phenotype and treatment responses are well documented. Technological advances now allow healthcare providers to improve the prevention and treatment of chronic diseases by stratifying patient populations. Although personalized medicine has great promise, it has, so far, been primarily applied in oncology. Wider adoption requires changes in the healthcare system and in clinical decision-making, and early applications of personalized medicine appear to require strong clinical utility and sufficient value to drive adoption. Personalized medicine is likely to enter dentistry as patients start to demand it and as new drugs are developed for pathways common to oral diseases.