Targeted Therapies: Immunologic Effects and Potential Applications Outside of Cancer

Metabolic Profiling to Assess Response to Targeted and Immune Therapy in Melanoma

There is currently no consensus to determine which advanced melanoma patients will benefit from targeted therapy, immunotherapy, or a combination of both, highlighting the critical need to identify early-response biomarkers to advanced melanoma therapy. The goal of this review is to provide scientific rationale to highlight the potential role of metabolic imaging to assess response to targeted and/or immune therapy in melanoma cancer. For that purpose, a brief overview of current melanoma treatments is provided. Then, current knowledge with respect to melanoma metabolism is described with an emphasis on major crosstalks between melanoma cell metabolism and signaling pathways involved in BRAF-targeted therapy as well as in immune checkpoint inhibition therapies. Finally, preclinical and clinical studies using metabolic imaging and/or profiling to assess response to melanoma treatment are summarized with a particular focus on PET (Positron Emission Tomography) imaging and 13C-MRS (Magnetic Resonance Spectroscopy) methods.

Twelve-Month Follow-up of the Immune Response After COVID-19 Vaccination in Patients with Genitourinary Cancers: A Prospective Cohort Analysis

BACKGROUND

Vaccinations against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have had a transformative impact on morbidity and mortality. However, the long-term impact of vaccination on patients with genitourinary cancers is currently unknown.

MATERIALS AND METHODS

This study aimed to assess seroconversion rates in patients with genitourinary cancers receiving COVID-19 vaccination. Patients with prostate cancer, renal cell carcinoma, or urothelial cancer who had not been vaccinated for COVID-19 were included. Blood samples were obtained at baseline and after 2, 6, and 12 months of one dose of an FDA-approved COVID-19 vaccine. Antibody titer analysis was performed using the SCoV-2 Detect IgG ELISA assay, and the results were reported as immune status ratio (ISR). A paired t-test was used for comparison of ISR values between timepoints. In addition, T-cell receptor (TCR) sequencing was performed to assess for differences in TCR repertoire 2 months after vaccination.

RESULTS

Out of 133 patients enrolled, 98 baseline blood samples were collected. At 2-, 6-, and 12-month time points 98, 70, and 50 samples were collected, respectively. Median age was 67 (IQR, 62-75), with the majority of patients diagnosed with prostate (55.1%) or renal cell carcinoma (41.8%). Compared to baseline (0.24 [95% CI, 0.19-0.31]) a significant increase in the geometric mean ISR values was observed at the 2-month timepoint (5.59 [4.76-6.55]) (P < .001). However, at the 6-month timepoint, a significant decrease in the ISR values was observed (4.66 [95% CI, 4.04-5.38]; P < .0001). Notably, at the 12-month timepoint, the addition of a booster dose resulted in an absolute increase in the ISR values compared to those who did not receive a booster dose (P = .04).

CONCLUSIONS

Only a minority of patients with genitourinary cancers did not ultimately achieve satisfactory seroconversion after receiving commercial COVID-19 vaccination. Cancer type or treatment rendered did not appear to affect the immune response mounted after vaccination.

High-Throughput Screening and Proteomic Characterization of Compounds Targeting Myeloid-Derived Suppressor Cells

Myeloid-derived suppressor cells (MDSC) are a heterogeneous cell population of incompletely differentiated immune cells. They are known to suppress T cell activity and are implicated in multiple chronic diseases, which make them an attractive cell population for drug discovery. Here, we characterized the baseline proteomes and phospho-proteomes of mouse MDSC differentiated from a progenitor cell line to a depth of 7000 proteins and phosphorylation sites. We also validated the cellular system for drug discovery by recapitulating and identifying known and novel molecular responses to the well-studied MDSC drugs entinostat and mocetinostat. We established a high-throughput drug screening platform using a MDSC/T cell coculture system and assessed the effects of ∼21,000 small molecule compounds on T cell proliferation and IFN-γ secretion to identify novel MDSC modulator. The most promising candidates were validated in a human MDSC system, and subsequent proteomic experiments showed significant upregulation of several proteins associated with the reduction of reactive oxygen species (ROS). Proteome-wide solvent-induced protein stability assays identified Acyp1 and Cd74 as potential targets, and the ROS-reducing drug phenotype was validated by measuring ROS levels in cells in response to compound, suggesting a potential mode of action. We anticipate that the data and chemical tools developed in this study will be valuable for further research on MDSC and related drug discovery.

A narrative review about CDK4/6 inhibitors in the setting of drug resistance: updates on biomarkers and therapeutic strategies in breast cancer

Background and Objective

Previous studies have demonstrated that cyclin-dependent kinase 4/6 (CDK4/6) inhibitors combined with endocrine therapy are able to effectively improve the prognosis of hormone receptor positive (HR+), human epidermal growth factor receptor 2 (HER2) negative advanced breast cancer (ABC). Five CDK4/6 inhibitors, palbociclib, ribociclib, abemaciclib, dalpiciclib, and trilaciclib have been approved for the treatment of this breast cancer subset at present. The efficacy and safety profile of adding these CDK4/6 inhibitors to endocrine therapies in HR+ breast cancer has been proved in a number of clinical trials. Besides, extending the application of CDK4/6 inhibitors to HER2+ or triple negative breast cancers (TNBCs) has also led to some clinical benefits.

Methods

A comprehensive, non-systematic review of the latest literature about CDK4/6 inhibitors resistance in breast cancer was conducted. The examined database was PubMed/MEDLINE, and the last search was run on October 1, 2022.

Key Content and Findings

In this review, the generation of CDK4/6 inhibitors resistance is related to gene alteration, pathway dysregulation, and tumor microenvironment change. With a deeper insight in the mechanisms of CDK4/6 inhibitor resistance, some biomarkers have presented the potential to predict drug resistance and showed prognostic value. Furthermore, in preclinical studies, some modified treatment strategies based on CDK4/6 inhibitors exhibited effectiveness on drug-resistant tumors, suggesting a preventable or reversible drug-resistant status.

Conclusions

This review clarified the current knowledge about mechanisms, the biomarkers to overcome the drug resistance of CDK4/6 inhibitors, and the latest clinical progresses about CDK4/6 inhibitors. Possible approaches to overcome CDK4/6 inhibitors resistance were further discussed. For example, using another CDK4/6 inhibitor, PI3K inhibitor, mTOR inhibitor, or a novel drug.

Pharmacologic targeting of Nedd8-activating enzyme reinvigorates T-cell responses in lymphoid neoplasia

Neddylation is a sequential enzyme-based process which regulates the function of E3 Cullin-RING ligase (CRL) and thus degradation of substrate proteins. Here we show that CD8+ T cells are a direct target for therapeutically relevant anti-lymphoma activity of pevonedistat, a Nedd8-activating enzyme (NAE) inhibitor. Pevonedistat-treated patient-derived CD8+ T cells upregulated TNFα and IFNγ and exhibited enhanced cytotoxicity. Pevonedistat induced CD8+ T-cell inflamed microenvironment and delayed tumor progression in A20 syngeneic lymphoma model. This anti-tumor effect lessened when CD8+ T cells lost the ability to engage tumors through MHC class I interactions, achieved either through CD8+ T-cell depletion or genetic knockout of B2M. Meanwhile, loss of UBE2M in tumor did not alter efficacy of pevonedistat. Concurrent blockade of NAE and PD-1 led to enhanced tumor immune infiltration, T-cell activation and chemokine expression and synergistically restricted tumor growth. shRNA-mediated knockdown of HIF-1α, a CRL substrate, abrogated the in vitro effects of pevonedistat, suggesting that NAE inhibition modulates T-cell function in HIF-1α-dependent manner. scRNA-Seq-based clinical analyses in lymphoma patients receiving pevonedistat therapy demonstrated upregulation of interferon response signatures in immune cells. Thus, targeting NAE enhances the inflammatory T-cell state, providing rationale for checkpoint blockade-based combination therapy.

Molecular targeted therapy for anticancer treatment

Since the initial clinical approval in the late 1990s and remarkable anticancer effects for certain types of cancer, molecular targeted therapy utilizing small molecule agents or therapeutic monoclonal antibodies acting as signal transduction inhibitors has served as a fundamental backbone in precision medicine for cancer treatment. These approaches are now used clinically as first-line therapy for various types of human cancers. Compared to conventional chemotherapy, targeted therapeutic agents have efficient anticancer effects with fewer side effects. However, the emergence of drug resistance is a major drawback of molecular targeted therapy, and several strategies have been attempted to improve therapeutic efficacy by overcoming such resistance. Herein, we summarize current knowledge regarding several targeted therapeutic agents, including classification, a brief biology of target kinases, mechanisms of action, examples of clinically used targeted therapy, and perspectives for future development.

Therapy resistance: opportunities created by adaptive responses to targeted therapies in cancer

Normal cells explore multiple states to survive stresses encountered during development and self-renewal as well as environmental stresses such as starvation, DNA damage, toxins or infection. Cancer cells co-opt normal stress mitigation pathways to survive stresses that accompany tumour initiation, progression, metastasis and immune evasion. Cancer therapies accentuate cancer cell stresses and invoke rapid non-genomic stress mitigation processes that maintain cell viability and thus represent key targetable resistance mechanisms. In this Review, we describe mechanisms by which tumour ecosystems, including cancer cells, immune cells and stroma, adapt to therapeutic stresses and describe three different approaches to exploit stress mitigation processes: (1) interdict stress mitigation to induce cell death; (2) increase stress to induce cellular catastrophe; and (3) exploit emergent vulnerabilities in cancer cells and cells of the tumour microenvironment. We review challenges associated with tumour heterogeneity, prioritizing actionable adaptive responses for optimal therapeutic outcomes, and development of an integrative framework to identify and target vulnerabilities that arise from adaptive responses and engagement of stress mitigation pathways. Finally, we discuss the need to monitor adaptive responses across multiple scales and translation of combination therapies designed to take advantage of adaptive responses and stress mitigation pathways to the clinic.

Risk and Outcome of Breakthrough COVID-19 Infections in Vaccinated Patients With Cancer: Real-World Evidence From the National COVID Cohort Collaborative

PURPOSE

To provide real-world evidence on risks and outcomes of breakthrough COVID-19 infections in vaccinated patients with cancer using the largest national cohort of COVID-19 cases and controls.

METHODS

We used the National COVID Cohort Collaborative (N3C) to identify breakthrough infections between December 1, 2020, and May 31, 2021. We included patients partially or fully vaccinated with mRNA COVID-19 vaccines with no prior SARS-CoV-2 infection record. Risks for breakthrough infection and severe outcomes were analyzed using logistic regression.

RESULTS

A total of 6,860 breakthrough cases were identified within the N3C-vaccinated population, among whom 1,460 (21.3%) were patients with cancer. Solid tumors and hematologic malignancies had significantly higher risks for breakthrough infection (odds ratios [ORs] = 1.12, 95% CI, 1.01 to 1.23 and 4.64, 95% CI, 3.98 to 5.38) and severe outcomes (ORs = 1.33, 95% CI, 1.09 to 1.62 and 1.45, 95% CI, 1.08 to 1.95) compared with noncancer patients, adjusting for age, sex, race/ethnicity, smoking status, vaccine type, and vaccination date. Compared with solid tumors, hematologic malignancies were at increased risk for breakthrough infections (adjusted OR ranged from 2.07 for lymphoma to 7.25 for lymphoid leukemia). Breakthrough risk was reduced after the second vaccine dose for all cancers (OR = 0.04; 95% CI, 0.04 to 0.05), and for Moderna's mRNA-1273 compared with Pfizer's BNT162b2 vaccine (OR = 0.66; 95% CI, 0.62 to 0.70), particularly in patients with multiple myeloma (OR = 0.35; 95% CI, 0.15 to 0.72). Medications with major immunosuppressive effects and bone marrow transplantation were strongly associated with breakthrough risk among the vaccinated population.

CONCLUSION

Real-world evidence shows that patients with cancer, especially hematologic malignancies, are at higher risk for developing breakthrough infections and severe outcomes. Patients with vaccination were at markedly decreased risk for breakthrough infections. Further work is needed to assess boosters and new SARS-CoV-2 variants.

Combination of infra-red light with nanogold targeting macrophages in the treatment of Leishmania major infected BALB/C mice

PURPOSE

In the treatment of cutaneous leishmaniasis (CL), developing drug resistance, existing toxic effects of drugs and failure respond to treatment cause the need to try different treatment methods. We investigated the effect of gold-conjugated macrophage-specific antibody on amastigotes under infra-red light for the treatment of CL.

METHODS

Female BALB/c (4-8 weeks old, 20 ± 5 g weight) mice were used in the study. The L. major strain was inoculated on the soles of mice in amastigote form and subpassed. Nanogold (Au), Au + macrophage-specific antibody (MSA) modification and near infra-red (NIR) (5 seconds) were applied to mice groups that developed cutaneous leishmaniasis on their soles. On the 5th and 10th days of the treatment, the lesions were examined clinically and pathologically.

RESULTS

When the erythema values were examined, the highest decrease was calculated in the Au + MSA + NIR group in the measurements made on the 10^th day (p < 0.014). The best improvement in 10^th day measurements is in the NIR and Au + MSA + NIR groups when area values were examined (p = 0.011, p = 0.001). There was a statistically significant difference between the groups in terms of parasite load (PL) (p < 0.005) in pathological evaluation. According to PL grouping, the best result is NIR (p = 0.002). When both main titles (clinical and pathological) are examined, the Au + MSA + NIR group is thought to have an optimal therapeutical feature.

CONCLUSIONS

Au + MSA + NIR combination could be a new treatment approach for CL treatment.

An Update on the Status of Vaccine Development for SARS-CoV-2 Including Variants. Practical Considerations for COVID-19 Special Populations

The progress in the development of various vaccine platforms against SARS-CoV-2 have been rather remarkable owing to advancement in molecular and biologic sciences. Most of the current vaccines and those in development focus on targeting the viral spike proteins by generating antibodies of varying spectrum. These vaccines represent a variety of platforms including whole virus vaccines, viral vector vaccines, nucleic acid vaccines representing RNA, DNA, and their hybrid forms.The therapeutic efficacy of these vaccines varies owing to their pharmacodynamic individualities. COVID-19 variants are capable of inducing different pathologic responses and some of which may be resistant to antibodies generated by current vaccines. The current clinical use of these vaccines has been through emergency use authorization until recently. Moreover, the efficacy and safety of these vaccines have been tested in substantial numbers of individuals but studies in special populations that better reflect the global population are pending results. These specialized populations include young children, immunocompromised patients, pregnant individuals, and other specialized groups. Combination approaches, molecularly modified vaccination approaches, and vaccines conferring longer periods of immunity are being currently being investigated, as well as pharmacovigilance studies.The continual transformation of SARS-CoV-2 and its variants are of concern along with the breakthrough infections. These considerations pose new challenges for the development of vaccination platforms. For this purpose, booster doses, combination vaccine approaches, and other modalities are being discussed. This review provides an updated account of currently available vaccines and those in advanced development with reference to their composition and mechanisms of action.A discussion on the use of vaccines in special populations including immunocompromised patients, pregnant women and other specialized populations are also included.

Identification of a basement membrane-related gene signature for predicting prognosis and estimating the tumor immune microenvironment in breast cancer

INTRODUCTION

Breast cancer (BC) is the most common malignancy in the world and has a high cancer-related mortality rate. Basement membranes (BMs) guide cell polarity, differentiation, migration and survival, and their functions are closely related to tumor diseases. However, few studies have focused on the association of basement membrane-related genes (BMRGs) with BC. This study aimed to explore the prognostic features of BMRGs in BC and provide new directions for the prevention and treatment of BC.

METHODS

We collected transcriptomic and clinical data of BC patients from TCGA and GEO datasets and constructed a predictive signature for BMRGs by using univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analysis. The reliability of the model was further evaluated and validated by Kaplan-Meier survival curves and receiver operating characteristic curves (ROC). Column line plots and corresponding calibration curves were constructed. Possible biological pathways were investigated by enrichment analysis. Afterward, we assessed the mutation status by tumor mutational burden (TMB) analysis and compared different subtypes using cluster analysis. Finally, we examined drug treatment sensitivity and immunological correlation to lay the groundwork for more in-depth studies in this area.

RESULTS

The prognostic risk model consisted of 7 genes (FBLN5, ITGB2, LAMC3, MMP1, EVA1B, SDC1, UNC5A). After validation, we found that the model was highly reliable and could accurately predict the prognosis of BC patients. Cluster analysis showed that patients with cluster 1 had more sensitive drugs and had better chances of better clinical outcomes. In addition, TMB, immune checkpoint, immune status, and semi-inhibitory concentrations were significantly different between high and low-risk groups, with lower-risk patients having the better anti-cancer ability.

DISCUSSION

The basement membrane-related gene signature that we established can be applied as an independent prognostic factor for BC and can provide a reference for individualized treatment of BC patients.

New Advances in the Research of Resistance to Neoadjuvant Chemotherapy in Breast Cancer

Breast cancer has an extremely high incidence in women, and its morbidity and mortality rank first among female tumors. With the increasing development of medicine today, the clinical application of neoadjuvant chemotherapy has brought new hope to the treatment of breast cancer. Although the efficacy of neoadjuvant chemotherapy has been confirmed, drug resistance is one of the main reasons for its treatment failure, contributing to the difficulty in the treatment of breast cancer. This article focuses on multiple mechanisms of action and expounds a series of recent research advances that mediate drug resistance in breast cancer cells. Drug metabolizing enzymes can mediate a catalytic reaction to inactivate chemotherapeutic drugs and develop drug resistance. The drug efflux system can reduce the drug concentration in breast cancer cells. The combination of glutathione detoxification system and platinum drugs can cause breast cancer cells to be insensitive to drugs. Changes in drug targets have led to poorer efficacy of HER2 receptor inhibitors. Moreover, autophagy, epithelial–mesenchymal transition, and tumor microenvironment can all contribute to the development of resistance in breast cancer cells. Based on the relevant research on the existing drug resistance mechanism, the current treatment plan for reversing the resistance of breast cancer to neoadjuvant chemotherapy is explored, and the potential drug targets are analyzed, aiming to provide a new idea and strategy to reverse the resistance of neoadjuvant chemotherapy drugs in breast cancer.

COVID-19 vaccines for patients with cancer: benefits likely outweigh risks

Less than a year since the start of the COVID-19 pandemic, ten vaccines against SARS-CoV-2 have been approved for at least limited use, with over sixty others in clinical trials. This swift achievement has generated excitement and arrives at a time of great need, as the number of COVID-19 cases worldwide continues to rapidly increase. Two vaccines are currently approved for full use, both built on mRNA and lipid nanotechnology platforms, a success story of mRNA technology 20 years in the making. For patients with cancer, questions arise around the safety and efficacy of these vaccines in the setting of immune alterations engendered by their malignancy and/or therapies. We summarize the current data on leading COVID-19 vaccine candidates and vaccination of patients undergoing immunomodulatory cancer treatments. Most current cancer therapeutics should not prevent the generation of protective immunity. We call for more research in this area and recommend that the majority of patients with cancer receive COVID vaccinations when possible.

COVID-19 vaccines for patients with cancer: benefits likely outweigh risks

Less than a year since the start of the COVID-19 pandemic, ten vaccines against SARS-CoV-2 have been approved for at least limited use, with over sixty others in clinical trials. This swift achievement has generated excitement and arrives at a time of great need, as the number of COVID-19 cases worldwide continues to rapidly increase. Two vaccines are currently approved for full use, both built on mRNA and lipid nanotechnology platforms, a success story of mRNA technology 20 years in the making. For patients with cancer, questions arise around the safety and efficacy of these vaccines in the setting of immune alterations engendered by their malignancy and/or therapies. We summarize the current data on leading COVID-19 vaccine candidates and vaccination of patients undergoing immunomodulatory cancer treatments. Most current cancer therapeutics should not prevent the generation of protective immunity. We call for more research in this area and recommend that the majority of patients with cancer receive COVID vaccinations when possible.

Role of epidermal growth factor receptor inhibitor-induced interferon pathway signaling in the head and neck squamous cell carcinoma therapeutic response

BACKGROUND

Epidermal growth factor receptor (EGFR) is frequently amplified or overexpressed in head and neck squamous cell carcinoma (HNSCC) and is a clinically validated target for the therapeutic antibody, cetuximab, in the management of this cancer. The degree of response to EGFR inhibitors measured by tumor shrinkage varies widely among HNSCC patients, and the biological mechanisms that underlie therapeutic heterogeneity amongst HNSCC patients remain ill-defined.

METHODS

EGFR-dependent human and murine HNSCC cell lines were treated with the EGFR/ERBB inhibitors, gefitinib and AZD8931, and submitted to RNAseq, GSEA, and qRT-PCR. Conditioned media was analyzed by ELISA and Luminex assays. Murine HNSCC tumors were stained for T cell markers by immunofluorescence. Primary HSNCC patient specimens treated with single agent cetuximab were stained with Vectra multispectral immunofluorescence.

RESULTS

The transcriptional reprogramming response to EGFR/ERBB-specific TKIs was measured in a panel of EGFR-dependent human HNSCC cell lines and interferon (IFN) α and γ responses identified as top-ranked TKI-induced pathways. Despite similar drug sensitivity, responses among 7 cell lines varied quantitatively and qualitatively, especially regarding the induced chemokine and cytokine profiles. Of note, the anti-tumorigenic chemokine, CXCL10, and the pro-tumorigenic factor, IL6, exhibited wide-ranging and non-overlapping induction. Similarly, AZD8931 exerted potent growth inhibition, IFNα/IFNγ pathway activation, and CXCL10 induction in murine B4B8 HNSCC cells. AZD8931 treatment of immune-competent mice bearing orthotopic B4B8 tumors increased CD8 + T cell content and the therapeutic response was abrogated in nu/nu mice relative to BALB/c mice. Finally, Vectra 3.0 analysis of HNSCC patient tumors prior to and after 3-4 weeks of single agent cetuximab treatment revealed increased CD8 + T cell content in specimens from patients exhibiting a therapeutic response relative to non-responders.

CONCLUSIONS

The findings reveal heterogeneous, tumor cell-intrinsic, EGFR/ERBB inhibitor-induced IFN pathway activation in HNSCC and suggest that individual tumor responses to oncogene-targeted agents are a sum of direct growth inhibitory effects and variably-induced participation of host immune cells.

Ex Vivo Culture Models to Indicate Therapy Response in Head and Neck Squamous Cell Carcinoma

Head and neck squamous cell carcinoma (HNSCC) is characterized by a poor 5 year survival and varying response rates to both standard-of-care and new treatments. Despite advances in medicine and treatment methods, mortality rates have hardly decreased in recent decades. Reliable patient-derived tumor models offer the chance to predict therapy response in a personalized setting, thereby improving treatment efficacy by identifying the most appropriate treatment regimen for each patient. Furthermore, ex vivo tumor models enable testing of novel therapies before introduction in clinical practice. A literature search was performed to identify relevant literature describing three-dimensional ex vivo culture models of HNSCC to examine sensitivity to chemotherapy, radiotherapy, immunotherapy and targeted therapy. We provide a comprehensive overview of the currently used three-dimensional ex vivo culture models for HNSCC with their advantages and limitations, including culture success percentage and comparison to the original tumor. Furthermore, we evaluate the potential of these models to predict patient therapy response.

Sweet syndrome as an adverse reaction to tyrosine kinase inhibitors: A review

Tyrosine kinase inhibitors are a class of targeted anticancer drugs that inhibit cancer cell proliferation by inactivating proteins involved in signal transduction cascades. Various cutaneous adverse events have been observed after tyrosine kinase inhibitor administration, including Sweet syndrome. We queried the PubMed database to identify 14 cases of Sweet syndrome thought to be secondary to tyrosine kinase inhibitors. Tyrosine kinase inhibitor-induced Sweet syndrome had a median of 2 months latency following drug administration. All cases but one had morphologic features classic for Sweet syndrome (erythematous and tender papules, plaques, or nodules). All cases also had classic histopathologic findings (dermal neutrophilic infiltrate without vasculitis or necrosis). Using diagnostic criteria for drug-induced Sweet syndrome and the Naranjo Drug Reaction Probability Scale for a drug-induced cutaneous eruption, we found that six cases favored a drug-induced etiology over malignancy, two cases favored a malignancy-associated Sweet syndrome, and the remaining eight met drug-induced Sweet syndrome criteria but had low Naranjo scores. Nine cases resulted in medication discontinuation, while five cases continued anticancer therapy and were treated only with corticosteroids with quick resolution of skin lesions. Dermatologists should be aware of this adverse cutaneous reaction to tyrosine kinase inhibitors and should treat on a case-by-case basis, though limited evidence in this review suggests that oncologic therapy may safely be continued with prompt corticosteroid treatment.

Translating mesothelioma molecular genomics and dependencies into precision oncology-based therapies

Malignant pleural mesothelioma (MPM) is a rare, yet lethal asbestos-induced cancer and despite marked efforts to reduce occupational exposure, the incidence has not yet significantly declined. Since 2003, combined treatment with a platinum-based agent and pemetrexed has been the first-line therapy and no effective or approved second-line treatments have emerged. The seemingly slow advance in developing new MPM treatments does not appear to be related to a low level of clinical and pre-clinical research activity. Rather, we suggest that a key hurdle in successfully translating basic discovery into novel MPM therapeutics is the underlying assumption that as a rare cancer, it will also be molecularly and genetically homogeneous. In fact, lung adenocarcinoma and melanoma only benefitted from precision oncology upon full appreciation of the high degree of molecular heterogeneity inherent in these cancers, especially regarding the diversity of oncogenic drivers. Herein, we consider the recent explosion of molecular and genetic information that has become available regarding MPM and suggest ways in which the unfolding landscape may guide identification of novel therapeutic vulnerabilities within subsets of MPM that can be targeted in a manner consistent with the tenets of precision oncology.

Molecular mechanisms of resistance to CDK4/6 inhibitors in breast cancer: A review

Deregulation of the cyclin D-CDK4/6-INK4-RB pathway leading to uncontrolled cell proliferation, is frequently observed in breast cancer. Currently, three selective CDK4/6 inhibitors have been FDA approved: palbociclib, ribociclib and abemaciclib. Despite promising clinical outcomes, intrinsic or acquired resistance to CDK4/6 inhibitors has limited the success of these treatments; therefore, the development of various strategies to overcome this resistance is of great importance. We highlight the various mechanisms that are directly or indirectly responsible for resistance to CDK4/6 inhibitors, categorizing them into two broad groups; cell cycle-specific mechanisms and cell cycle-nonspecific mechanisms. Elucidation of the diverse mechanisms through which resistance to CDK4/6 inhibitors occurs, may aid in the design of novel therapeutic strategies to improve patient outcomes. This review summarizes the currently available knowledge regarding mechanisms of resistance to CDK4/6 inhibitors, and possible therapeutic strategies that may overcome this resistance as well.

Three-Dimensional in Vitro Cell Culture Models in Drug Discovery and Drug Repositioning

Drug development is a lengthy and costly process that proceeds through several stages from target identification to lead discovery and optimization, preclinical validation and clinical trials culminating in approval for clinical use. An important step in this process is high-throughput screening (HTS) of small compound libraries for lead identification. Currently, the majority of cell-based HTS is being carried out on cultured cells propagated in two-dimensions (2D) on plastic surfaces optimized for tissue culture. At the same time, compelling evidence suggests that cells cultured in these non-physiological conditions are not representative of cells residing in the complex microenvironment of a tissue. This discrepancy is thought to be a significant contributor to the high failure rate in drug discovery, where only a low percentage of drugs investigated ever make it through the gamut of testing and approval to the market. Thus, three-dimensional (3D) cell culture technologies that more closely resemble in vivo cell environments are now being pursued with intensity as they are expected to accommodate better precision in drug discovery. Here we will review common approaches to 3D culture, discuss the significance of 3D cultures in drug resistance and drug repositioning and address some of the challenges of applying 3D cell cultures to high-throughput drug discovery.