Immune checkpoint inhibitors (ICI) targeting CTLA-4 and the PD-1/PD-L1 axis have shown unprecedented clinical activity in several types of cancer and are rapidly transforming the practice of medical ...oncology. Whereas cytotoxic chemotherapy and small molecule inhibitors ('targeted therapies') largely act on cancer cells directly, immune checkpoint inhibitors reinvigorate anti-tumour immune responses by disrupting co-inhibitory T-cell signalling. While resistance routinely develops in patients treated with conventional cancer therapies and targeted therapies, durable responses suggestive of long-lasting immunologic memory are commonly seen in large subsets of patients treated with ICI. However, initial response appears to be a binary event, with most non-responders to single-agent ICI therapy progressing at a rate consistent with the natural history of disease. In addition, late relapses are now emerging with longer follow-up of clinical trial populations, suggesting the emergence of acquired resistance. As robust biomarkers to predict clinical response and/or resistance remain elusive, the mechanisms underlying innate (primary) and acquired (secondary) resistance are largely inferred from pre-clinical studies and correlative clinical data. Improved understanding of molecular and immunologic mechanisms of ICI response (and resistance) may not only identify novel predictive and/or prognostic biomarkers, but also ultimately guide optimal combination/sequencing of ICI therapy in the clinic. Here we review the emerging clinical and pre-clinical data identifying novel mechanisms of innate and acquired resistance to immune checkpoint inhibition.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Triple-negative breast cancers (TNBCs) are a heterogeneous set of cancers that are defined by the absence of hormone receptor expression and HER2 amplification. Here, we found that inducible IκB ...kinase-related (IKK-related) kinase IKBKE expression and JAK/STAT pathway activation compose a cytokine signaling network in the immune-activated subset of TNBC. We found that treatment of cultured IKBKE-driven breast cancer cells with CYT387, a potent inhibitor of TBK1/IKBKE and JAK signaling, impairs proliferation, while inhibition of JAK alone does not. CYT387 treatment inhibited activation of both NF-κB and STAT and disrupted expression of the protumorigenic cytokines CCL5 and IL-6 in these IKBKE-driven breast cancer cells. Moreover, in 3D culture models, the addition of CCL5 and IL-6 to the media not only promoted tumor spheroid dispersal but also stimulated proliferation and migration of endothelial cells. Interruption of cytokine signaling by CYT387 in vivo impaired the growth of an IKBKE-driven TNBC cell line and patient-derived xenografts (PDXs). A combination of CYT387 therapy with a MEK inhibitor was particularly effective, abrogating tumor growth and angiogenesis in an aggressive PDX model of TNBC. Together, these findings reveal that IKBKE-associated cytokine signaling promotes tumorigenicity of immune-driven TNBC and identify a potential therapeutic strategy using clinically available compounds.
While important strides have been made in cancer therapy by targeting certain oncogenes, KRAS, the most common among them, remains refractory to this approach. In recent years, a deeper understanding ...of the critical importance of inflammation in promoting KRAS-driven oncogenesis has emerged, and applies across the different contexts of lung, pancreatic, and colorectal tumorigenesis. Here we review why these tissue types are particularly prone to developing KRAS mutations, and how inflammation conspires with KRAS signaling to fuel carcinogenesis. We discuss multiple lines of evidence that have established NF-κB, STAT3, and certain cytokines as key transducers of these signals, and data to suggest that targeting these pathways has significant clinical potential. Furthermore, recent work has begun to uncover how inflammatory signaling interacts with other KRAS regulated survival pathways such as autophagy and MAPK signaling, and that co-targeting these multiple nodes may be required to achieve real benefit. In addition, the impact of KRAS associated inflammatory signaling on the greater tumor microenvironment has also become apparent, and taking advantage of this inflammation by incorporating approaches that harness T cell anti-tumor responses represents another promising therapeutic strategy. Finally, we highlight the likelihood that the genomic complexity of KRAS mutant tumors will ultimately require tailored application of these therapeutic approaches, and that targeting inflammation early in the course of tumor development could have the greatest impact on eradicating this deadly disease.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Evaluating drug responses using primary patient-derived cells
represents a potentially rapid and efficient approach to screening for new treatment approaches. Here, we sought to identify neratinib ...combinations in
mutant non-small cell lung cancer (NSCLC) patient
enograft-
erived
rganotypic
pheroids (XDOTS) using a short-term
system.
We generated two
mutant NSCLC PDX models DFCI359 (
exon19 755_757LREdelinsRP) and DFCI315 (
exon20 V777_G778insGSP) and used the PDX tumors to generate XDOTS. Tumor spheroids were grown in a microfluidic device and treated
with neratinib-based drug combinations. Live/dead quantification was performed by dual-labeling deconvolution fluorescence microscopy. The most efficacious
combination was subsequently validated
using the DFCI359 and DFCI315 PDXs and a
genetically engineered mouse model.
Both neratinib and afatinib, but not gefitinib, induced cell death in DFCI359 XDOTS. The combinations of neratinib/trastuzumab and neratinib/temsirolimus enhanced the therapeutic benefit of neratinib alone in DFCI315 and DFCI359. The combination of neratinib and trastuzumab
was more effective compared with single-agent neratinib or trastuzumab and was associated with more robust inhibition of HER2 and downstream signaling.
The XDOTS platform can be used to evaluate therapies and therapeutic combinations
using PDX tumors. This approach may accelerate the identification and clinical development of therapies for targets with no or few existing models and/or therapies.
Targeting the mutant p53 secretome Sehgal, Kartik; Barbie, David A
The Journal of clinical investigation,
01/2021, Volume:
131, Issue:
1
Journal Article
Peer reviewed
Open access
While p53 is the most highly mutated and perhaps best studied tumor suppressor protein related to cancer, it remains refractory to targeted therapeutic strategies. In this issue of the JCI, Tan and ...colleagues investigated the mechanistic basis of the mutant p53 secretome in preclinical models of lung adenocarcinoma. The authors uncovered miR-34a as a regulator of a conventional protein secretion axis, which is mediated by three proteins: the Golgi reassembly and stacking protein 55 kDa (GRASP55), basic leucine zipper nuclear factor 1, and myosin IIA. Inhibition of GRASP55 in TP53-deficient lung adenocarcinoma suppressed protumorigenic secretion of osteopontin/secreted phosphoprotein 1 and insulin-like growth factor binding protein 2 and reduced tumor growth and metastases in mice as well as in patient-derived xenografts. These results provide a therapeutic opportunity to target downstream effects of p53 loss.
Microfluidic culture has the potential to revolutionize cancer diagnosis and therapy. Indeed, several microdevices are being developed specifically for clinical use to test novel cancer therapeutics. ...To be effective, these platforms need to replicate the continuous interactions that exist between tumor cells and non-tumor cell elements of the tumor microenvironment through direct cell-cell or cell-matrix contact or by the secretion of signaling factors such as cytokines, chemokines and growth factors. Given the challenges of personalized or precision cancer therapy, especially with the advent of novel immunotherapies, a critical need exists for more sophisticated
ex vivo
diagnostic systems that recapitulate patient-specific tumor biology with the potential to predict response to immune-based therapies in real-time. Here, we present details of a method to screen for the response of patient tumors to immune checkpoint blockade therapy, first reported in Jenkins
et al. Cancer Discovery
, 2018,
8
, 196-215, with updated evaluation of murine- and patient-derived organotypic tumor spheroids (MDOTS/PDOTS), including evaluation of the requirement for 3D microfluidic culture in MDOTS, demonstration of immune-checkpoint sensitivity of PDOTS, and expanded evaluation of tumor-immune interactions using RNA-sequencing to infer changes in the tumor-immune microenvironment. We also examine some potential improvements to current systems and discuss the challenges in translating such diagnostic assays to the clinic.
Microfluidic culture has the potential to revolutionize cancer diagnosis and therapy.
Small cell lung cancer (SCLC) is an aggressive disease with high mortality, and the identification of effective pharmacological strategies to target SCLC biology represents an urgent need. Using a ...high-throughput cellular screen of a diverse chemical library, we observe that SCLC is sensitive to transcription-targeting drugs, in particular to THZ1, a recently identified covalent inhibitor of cyclin-dependent kinase 7. We find that expression of super-enhancer-associated transcription factor genes, including MYC family proto-oncogenes and neuroendocrine lineage-specific factors, is highly vulnerability to THZ1 treatment. We propose that downregulation of these transcription factors contributes, in part, to SCLC sensitivity to transcriptional inhibitors and that THZ1 represents a prototype drug for tailored SCLC therapy.
•SCLC is vulnerable to inhibition of RNAPII-mediated transcription by THZ1•SCLC super-enhancers associate with proto-oncogenes and key SCLC identity genes•THZ1 preferentially targets super-enhancer-driven transcription factor genes•THZ1 represents a first-in-class experimental agent for the treatment of SCLC
Small cell lung cancer (SCLC) is an aggressive disease for which effective therapies are needed. Christensen et al. discover that SCLC is sensitive to THZ1, which is a covalent inhibitor of the transcriptional regulator CDK7 and downregulates the expression of key transcription factors that drive the disease.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Small-cell lung cancer (SCLC) is an aggressive malignancy in which inhibitors of PARP have modest single-agent activity. We performed a phase I/II trial of combination olaparib tablets and ...temozolomide (OT) in patients with previously treated SCLC. We established a recommended phase II dose of olaparib 200 mg orally twice daily with temozolomide 75 mg/m
daily, both on days 1 to 7 of a 21-day cycle, and expanded to a total of 50 patients. The confirmed overall response rate was 41.7% (20/48 evaluable); median progression-free survival was 4.2 months 95% confidence interval (CI), 2.8-5.7; and median overall survival was 8.5 months (95% CI, 5.1-11.3). Patient-derived xenografts (PDX) from trial patients recapitulated clinical OT responses, enabling a 32-PDX coclinical trial. This revealed a correlation between low basal expression of inflammatory-response genes and cross-resistance to both OT and standard first-line chemotherapy (etoposide/platinum). These results demonstrate a promising new therapeutic strategy in SCLC and uncover a molecular signature of those tumors most likely to respond. SIGNIFICANCE: We demonstrate substantial clinical activity of combination olaparib/temozolomide in relapsed SCLC, revealing a promising new therapeutic strategy for this highly recalcitrant malignancy. Through an integrated coclinical trial in PDXs, we then identify a molecular signature predictive of response to OT, and describe the common molecular features of cross-resistant SCLC.
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KRAS-LKB1 (KL) mutant lung cancers silence STING owing to intrinsic mitochondrial dysfunction, resulting in T cell exclusion and resistance to programmed cell death (ligand) 1 (PD-L1) blockade. Here ...we discover that KL cells also minimize intracellular accumulation of 2′3′-cyclic GMP-AMP (2′3′-cGAMP) to further avoid downstream STING and STAT1 activation. An unbiased screen to co-opt this vulnerability reveals that transient MPS1 inhibition (MPS1i) potently re-engages this pathway in KL cells via micronuclei generation. This effect is markedly amplified by epigenetic de-repression of STING and only requires pulse MPS1i treatment, creating a therapeutic window compared with non-dividing cells. A single course of decitabine treatment followed by pulse MPS1i therapy restores T cell infiltration in vivo, enhances anti-PD-1 efficacy, and results in a durable response without evidence of significant toxicity.
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•KL mutant cells are sensitive to intracellular 2′-3′cGAMP accumulation•MPS1i potently generates 2′-3′-cGAMP via cGAS sensing of micronuclei•De-repression of STING further co-opts this vulnerability and recruits T/NK cells•Sequential DNMT-MPS1 inhibitor treatment effectively restores immunogenicity in vivo
KRAS-LKB1 (KL) lung cancers epigenetically silence STING and resist PD-1 blockade. Here, Kitajima et al. discover that MPS1 inhibition strongly reactivates KL cGAS-STING signaling following epigenetic STING de-repression. Microfluidic and animal models demonstrate potent T/NK cell recruitment by this combination, reversing anti-PD-1 resistance and revealing a strategy translatable to the clinic.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
An alternative to therapeutic targeting of oncogenes is to perform “synthetic lethality” screens for genes that are essential only in the context of specific cancer-causing mutations. We used ...high-throughput RNA interference (RNAi) to identify synthetic lethal interactions in cancer cells harboring mutant
KRAS, the most commonly mutated human oncogene. We find that cells that are dependent on mutant
KRAS exhibit sensitivity to suppression of the serine/threonine kinase STK33 irrespective of tissue origin, whereas
STK33 is not required by
KRAS-independent cells. STK33 promotes cancer cell viability in a kinase activity-dependent manner by regulating the suppression of mitochondrial apoptosis mediated through S6K1-induced inactivation of the death agonist BAD selectively in mutant
KRAS-dependent cells. These observations identify
STK33 as a target for treatment of mutant
KRAS-driven cancers and demonstrate the potential of RNAi screens for discovering functional dependencies created by oncogenic mutations that may enable therapeutic intervention for cancers with “undruggable” genetic alterations.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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