Myoststin Knockout Improves Cachexia And Inhibits Tumor Growth

Cachexia- induced muscle wasting is a problem in cancer. This paper tests the hypothesis that knocking out myostatin expression could help with this problem, since myostatin inhibits muscle growth and differentiation.  In mice, this hypothesis proved correct and also some inhibition of tumor growth was also observed - these are all encouraging findings.  The abstract of the paper:

Cachexia is a muscle-wasting syndrome that contributes significantly to morbidity and mortality of many patients with advanced cancers. However, little is understood about how the severe loss of skeletal muscle characterizing this condition occurs. In the current study, we tested the hypothesis that the muscle protein myostatin is involved in mediating the pathogenesis of cachexia-induced muscle wasting in tumor-bearing mice. Myostatin gene inactivation prevented the severe loss of skeletal muscle mass induced in mice engrafted with Lewis lung carcinoma (LLC) cells or in Apc(Min) (/+) mice, an established model of colorectal cancer and cachexia. Mechanistically, myostatin loss attenuated the activation of muscle fiber proteolytic pathways by inhibiting the expression of atrophy-related genes, MuRF1 and MAFbx/Atrogin-1, along with autophagy-related genes. Notably, myostatin loss also impeded the growth of LLC tumors, the number and the size of intestinal polyps in Apc(Min) (/+) mice, thus strongly increasing survival in both models. Gene expression analysis in the LLC model showed this phenotype to be associated with reduced expression of genes involved in tumor metabolism, activin signaling, and apoptosis. Taken together, our results reveal an essential role for myostatin in the pathogenesis of cancer cachexia and link this condition to tumor growth, with implications for furthering understanding of cancer as a systemic disease.

More research is needed.

Identifying And Targeting Cancer Stem Cells

Here is a paper from several years ago demonstrating further identification of (colon) cancer stem cells, with information on targeting such cells for therapy.  Abstract:

The cancer stem cell (CSC) theory highlights a self-renewing subpopulation of cancer cells that fuels tumour growth. The existence of human CSCs is mainly supported by xeno-transplantation of prospectively isolated cells, but their clonal dynamics and plasticity remain elusive. Here, we demonstrate that human LGR5+ colorectal cancer cells serve as CSCs in growing cancer tissues. Lineage-tracing experiments with a CRISPR-Cas9-mediated LGR5-CreER knock-in allele reveal self-renewal and differentiation capacity of LGR5+ tumour cells. Selective ablation of LGR5+ CSCs in LGR5-iCaspase9 knock-in organoids leads to tumour regression, followed by tumour regrowth driven by re-emerging LGR5+ CSCs. KRT20-CreER marks differentiated cancer cells that constantly diminish in tumour tissues, while reverting to LGR5+ CSCs and contributing to tumour regrowth after LGR5+ CSC ablation. We also show that combined chemotherapy potentiates LGR5+ CSCs targeting. These data provide insights into the plasticity of CSCs and their potential as a therapeutic target in human colorectal cancer.

We'll be following further developments in this field.

Coffee And Cancer Risk

Here is a paper on coffee consumption and cancer risk from several years ago,  Bottom like is that there doesn't seem to be a big effect either way; coffee can cause decreased risk for some cancers, but possibly increased risk for childhood leukemia with maternal coffee drinking during pregnancy. The data are "limited and inconsistent" in some cases; overall it seems like a "wash" based on these findings, no big effect. Abstract:

We reviewed available evidence on coffee drinking and the risk of all cancers and selected cancers updated to May 2016. Coffee consumption is not associated with overall cancer risk. A meta-analysis reported a pooled relative risk (RR) for an increment of 1 cup of coffee/day of 1.00 [95% confidence interval (CI): 0.99-1.01] for all cancers. Coffee drinking is associated with a reduced risk of liver cancer. A meta-analysis of cohort studies found an RR for an increment of consumption of 1 cup/day of 0.85 (95% CI: 0.81-0.90) for liver cancer and a favorable effect on liver enzymes and cirrhosis. Another meta-analysis showed an inverse relation for endometrial cancer risk, with an RR of 0.92 (95% CI: 0.88-0.96) for an increment of 1 cup/day. A possible decreased risk was found in some studies for oral/pharyngeal cancer and for advanced prostate cancer. Although data are mixed, overall, there seems to be some favorable effect of coffee drinking on colorectal cancer in case-control studies, in the absence of a consistent relation in cohort studies. For bladder cancer, the results are not consistent; however, any possible direct association is not dose and duration related, and might depend on a residual confounding effect of smoking. A few studies suggest an increased risk of childhood leukemia after maternal coffee drinking during pregnancy, but data are limited and inconsistent. Although the results of studies are mixed, the overall evidence suggests no association of coffee intake with cancers of the stomach, pancreas, lung, breast, ovary, and prostate overall. Data are limited, with RR close to unity for other neoplasms, including those of the esophagus, small intestine, gallbladder and biliary tract, skin, kidney, brain, thyroid, as well as for soft tissue sarcoma and lymphohematopoietic cancer.

I don't drink coffee myself, but based on these data overall it seems not do any harm taking all risks together - although pregnant women may want to ask their doctor about the risk in that specific case.

Wnt Signaling And TB

Here is an interesting paper from several years ago discussing a potential link between a signaling pathway more commonly associated with (colorectal) cancer and the immune response to tuberculosis. Abstract:

Mycobacterium tuberculosis (M. tuberculosis), an intracellular pathogenic Gram-positive bacterium, is the cause of tuberculosis (TB), a major worldwide human infectious disease. The innate immune system is the first host defense against M. tuberculosis. The recognition of this pathogen is mediated by several classes of pattern recognition receptors expressed on the host innate immune cells, including Toll-like receptors, Nod-like receptors, and C-type lectin receptors like Dectin-1, the Mannose receptor, and DC-SIGN. M. tuberculosis interaction with any of these receptors activates multiple signaling pathways among which the protein kinase C, the MAPK, and the NFκB pathways have been widely studied. These pathways have been implicated in macrophage invasion, M. tuberculosis survival, and impaired immune response, thus promoting a successful infection and disease. Interestingly, the Wnt signaling pathway, classically regarded as a pathway involved in the control of cell proliferation, migration, and differentiation in embryonic development, has recently been involved in immunoregulatory mechanisms in infectious and inflammatory diseases, such as TB, sepsis, psoriasis, rheumatoid arthritis, and atherosclerosis. In this review, we present the current knowledge supporting a role for the Wnt signaling pathway during macrophage infection by M. tuberculosis and the regulation of the immune response against M. tuberculosis. Understanding the cross talk between different signaling pathways activated by M. tuberculosis will impact on the search for new therapeutic targets to fuel the rational design of drugs aimed to restore the immunological response against M. tuberculosis.

Once again, the importance of basic science research is seen.  First, the Wnt pathway was studied as a model of cell signaling, including in the fruit fly model.  Then, the absolute importance of this pathway in cancer, particularly colorectal cancer, was determined.  Next, Wnt signaling was identified as important in many other disorders, including neurodegenerative, and now has important implications in infectious disease.

Exercise, DKK1, SFRP1, And Cancer

Here is a study on breast cancer patients suggesting that physical activity/exercise can reduce blood levels of cell signaling factors, one of which is associated with a poor prognosis for patients with various forms of cancer.  Abstract:

Wingless and integration site growth factor (Wnt) signaling is a tumorigenesis-related signaling pathway. Dickkpof-1 (DKK1) and secreted frizzled-related protein-1 (SFRP1) are endogenous negative regulators of Wnt/β-catenin signaling. Accumulating evidence indicates that higher serum levels of DKK1 are correlated with poor prognosis of various types of cancer. Here, we investigated whether exercise training causes changes in the serum levels of DKK1 and SFRP1 in patients with breast cancer.

METHODS:

Twenty-four breast cancer survivors, after chemo- or radiotherapy, participated in this single-blind randomized, controlled pilot study. Subjects were randomized to either an exercise program or a control group for 12 weeks and completed pre- and post-training tests for health-related fitness and body composition as well as blood biomarkers. The serum levels of DKK1 and SFRP1 were measured using enzyme-linked immunosorbent assay as the primary outcome.

RESULTS:

Exercise training for 12 weeks remarkably increased muscle strength, endurance, and flexibility and decreased body fat percentage, waist circumference, and visceral fat area (all p < 0.05). Exercise training lowered serum insulin levels and leptin/adiponectin ratios (all p < 0.05). The levels of DKK1 and SFRP1 were also significantly decreased by exercise training in breast cancer survivors (all p < 0.01).

CONCLUSIONS:

Our results indicate that DKK1 and SFRP1 may be potentially useful biomarkers for evaluating the beneficial effects of long-term exercise on physical fitness and metabolism as well as the prognosis of patients with cancer.

The benefits of exercise are many and the list of positive effects continues to grow.

Prevent Aging With Stem Cell Rejuvenation?

Discussion of a possible anti-aging approach, abstract:

Characterized by dysfunction of tissues, organs, organ systems and the whole organism, aging results from the reduced function of effective stem cell populations. Recent advances in aging research have demonstrated that old tissue stem cells can be rejuvenated for the purpose of maintaining the old-organ function by youthful re-calibration of the environment where stem cells reside. Biochemical cues regulating tissue stem cell function include molecular signaling pathways that interact between stem cells themselves and their niches. Historically, plasma fractions have been shown to contain factors capable of controlling age phenotypes; subsequently, signaling pathways involved in the aging process have been identified. Consequently, modulation of signaling pathways such as Notch/Delta, Wnt, transforming growth factor-β, JAK/STAT, mammalian target of rapamycin and p38 mitogen-activated protein kinase has demonstrated potential to rejuvenate stem cell function leading to organismic rejuvenation. Several synthetic agents and natural sources, such as phytochemicals and flavonoids, have been proposed to rejuvenate old stem cells by targeting these pathways. However, several concerns still remain to achieve effective organismic rejuvenation in clinical settings, such as possible carcinogenic actions; thus, further research is still required.

Note the point at the end about "possible carcinogenic actions."  Paradox: while the risk of most cancers increases with age, aging itself can be viewed as an anti-cancer mechanism, diminishing cell reproduction and stem cell activity (and elimination of stem cells) to prevent such cells with mutations from multiplying into tumors.  Thus, anti-aging approaches need to be cognizant of the cancer problem and find solutions to this possible problem.

Epigenomics And Cancer Heterogeneity

There can be considerable heterogeneity in cancers, and this can contribute to progression and resistance to therapy.  This heterogeneity can arise not only from DNA sequence changes (i.e., mutation) but also from epigenetic changes - changes in the modifications of chromosomes - on a single cell level, making one cell different than another with respect to gene expression, even if the gene sequences remain the same.  A paper of interest, abstract:

Cell-to-cell heterogeneity is a major driver of cancer evolution, progression, and emergence of drug resistance. Epigenomic variation at the single-cell level can rapidly create cancer heterogeneity but is difficult to detect and assess functionally.

RESULTS: We develop a strategy to bridge the gap between measurement and function in single-cell epigenomics. Using single-cell chromatin accessibility and RNA-seq data in K562 leukemic cells, we identify the cell surface marker CD24 as co-varying with chromatin accessibility changes linked to GATA transcription factors in single cells. Fluorescence-activated cell sorting of CD24 high versus low cells prospectively isolated GATA1 and GATA2 high versus low cells. GATA high versus low cells express differential gene regulatory networks, differential sensitivity to the drug imatinib mesylate, and differential self-renewal capacity. Lineage tracing experiments show that GATA/CD24hi cells have the capability to rapidly reconstitute the heterogeneity within the entire starting population, suggesting that GATA expression levels drive a phenotypically relevant source of epigenomic plasticity.
CONCLUSION: Single-cell chromatin accessibility can guide prospective characterization of cancer heterogeneity. Epigenomic subpopulations in cancer impact drug sensitivity and the clonal dynamics of cancer evolution.

Identifying these epigenetic changes can be the first step in developing novel approaches to reverse the changes and/or target those cells containing such changes, for therapeutic benefit.

Warburg Effect And Some Possible Cancer Treatments

The Warburg effect is important in cancer, since cancer cells rely more heavily than do normal cells on glycolysis for energy production.  This may point at therapies targeting this effect for patient benefit.  A paper is here, abstract:

As stated by Otto Warburg nearly a century ago, cancer is a metabolic disease, a fermentation caused by malfunctioning mitochondria, resulting in increased anabolism and decreased catabolism. Treatment should, therefore, aim at restoring the energy yield. To decrease anabolism, glucose uptake should be reduced (ketogenic diet). To increase catabolism, the oxidative phosphorylation should be restored. Treatment with a combination of α-lipoic acid and hydroxycitrate has been shown to be effective in multiple animal models. This treatment, in combination with conventional chemotherapy, has yielded extremely encouraging results in glioblastoma, brain metastasis and lung cancer. Randomized trials are necessary to confirm these preliminary data. The major limitation is the fact that the combination of α-lipoic acid and hydroxycitrate can only be effective if the mitochondria are still present and/or functional. That may not be the case in the most aggressive tumors. The increased intracellular alkalosis is a strong mitogenic signal, which bypasses most inhibitory signals. Concomitant correction of this alkalosis may be a very effective treatment in case of mitochondrial failure.

Note that a ketogenic diet is considered one mechanism whereby the Warburg effect can be leveraged for anti-cancer treatment.

Cancer Incidence In Different Parts Of The USA

Different forms of cancer seem more prevalent in some areas of the USA compared to others.  For example, read here. Part of abstract:

For many cancers, there were distinct clusters of counties with especially high mortality. The location of these clusters varied by type of cancer and were spread in different regions of the United States. Clusters of breast cancer were present in the southern belt and along the Mississippi River, while liver cancer was high along the Texas-Mexico border, and clusters of kidney cancer were observed in North and South Dakota and counties in West Virginia, Ohio, Indiana, Louisiana, Oklahoma, Texas, Alaska, and Illinois.
CONCLUSIONS AND RELEVANCE:
Cancer mortality declined overall in the United States between 1980 and 2014. Over this same period, there were important changes in trends, patterns, and differences in cancer mortality among US counties. These patterns may inform further research into improving prevention and treatment.

This differences can be due to genetic differences between demographic groups variably distributed in these regions, differences in lifestyle including diet and physical activity, different distribution of age groups in these regions, socioeconomic status and access to health care, etc.  As the authors state, hopefully this information can be useful in optimizing prevention and treatment.

More On Tumor Immune Evasion

One mechanism of tumor immune evasion (at least in mice) is discussed here, abstract:

Conventional type 1 dendritic cells (cDC1) are critical for antitumor immunity, and their abundance within tumors is associated with immune-mediated rejection and the success of immunotherapy. Here, we show that cDC1 accumulation in mouse tumors often depends on natural killer (NK) cells that produce the cDC1 chemoattractants CCL5 and XCL1. Similarly, in human cancers, intratumoral CCL5, XCL1, and XCL2 transcripts closely correlate with gene signatures of both NK cells and cDC1 and are associated with increased overall patient survival. Notably, tumor production of prostaglandin E2 (PGE2) leads to evasion of the NK cell-cDC1 axis in part by impairing NK cell viability and chemokine production, as well as by causing downregulation of chemokine receptor expression in cDC1. Our findings reveal a cellular and molecular checkpoint for intratumoral cDC1 recruitment that is targeted by tumor-derived PGE2 for immune evasion and that could be exploited for cancer therapy.

Genetic Variation And Immune Checkpoint Therapy

Patient response to immune checkpoint therapy is influenced by patient genotype.  It may be necessary to determine individual genetic variation before applying this therapy; alternatively, is it possible to adjust therapy to make it more effective even for patients with less optimal (for therapy) immune genotypes.  Abstract:

CD8+ T cell-dependent killing of cancer cells requires efficient presentation of tumor antigens by human leukocyte antigen class I (HLA-I) molecules. However, the extent to which patient-specific HLA-I genotype influences response to anti-PD-1 or anti-CTLA-4 is currently unknown. We determined the HLA-I genotype of 1,535 advanced cancer patients treated with immune checkpoint blockade (ICB). Maximal heterozygosity at HLA-I loci (A, B, and C) improved overall survival after ICB compared to patients who were homozygous for at least one HLA locus. In two independent melanoma cohorts, patients with the HLA-B44 supertype had extended survival, whereas the HLA-B62 supertype (including HLA-B*15:01) or somatic loss of heterozygosity at HLA-I, was associated with poor outcome. Molecular dynamics simulations of HLA-B*15:01 revealed unique elements that may impair CD8+ T cell recognition of neoantigens. Our results have important implications for predicting response to ICB and for the design of neoantigen-based therapeutic vaccines.

Colobronchial Fistula.

Here we see why investigating strange physical symptoms is important: a case of a colobronchial fistula.  

Multiple Myeloma Treatment Options

Treatment options for relapsing/progressing multiple myeloma; abstract:

Despite enormous advances, management of multiple myeloma (MM) remains challenging. Multiple factors impact the decision to treat or which regimen to use at MM relapse/progression. Recent major randomized controlled trials (RCTs) showed widely varying progression-free survivals (PFS), ranging from a median of 4 months (MM-003) to 23.6 months (ASPIRE). Based on these RCTs, next-generation proteasome inhibitors (carfilzomib and ixazomib), next-generation immunomodulatory agent (pomalidomide), and monoclonal antibodies (elotuzumab and daratumumab) were approved for relapsed and refractory MM. Daratumumab, targeting CD38, has multiple mechanisms of action including modulation of the immunosuppressive bone marrow micro-environment. In addition to the remarkable single agent activity in refractory MM, daratumumab produced deep responses and superior PFS in MM when combined with lenalidomide/dexamethasone, or bortezomib/dexamethasone. Other anti-CD38 antibodies, such as isatuximab and MOR202, are undergoing assessment. Elotuzumab, targeting SLAMF7, yielded superior response rates and PFS when combined with lenalidomide/dexamethasone. New combinations of these next generation novel agents and/or antibodies are undergoing clinical trials. Venetoclax, an oral BH3 mimetic inhibiting BCL2, showed single agent activity in MM with t(11;14), and is being studied in combination with bortezomib/dexamethasone. Selinexor, an Exportin-1 inhibitor, yielded promising results in quad- or penta-refractory MM including patients resistant to daratumumab. Pembrolizumab, an anti-PD1 check-point inhibitor, is being tested in combination with lenalidomide/dexamethasone or pomalidomide/dexamethasone. Chimeric antigen receptor-T cells targeting B-cell maturation antigen have yielded deep responses in RRMM. Finally, salvage autologous stem cell transplantation (ASCT) remains an important treatment in MM relapsing/progressing after a first ASCT. Herein, the clinical trial data of these agents are summarized, cautious interpretation of RCTs highlighted, and algorithm for salvage treatment of relapse/refractory MM proposed.Leukemia advance online publication, 19 December 2017; doi:10.1038/leu.2017.329.

Immune Checkpoint Inhibitor Therapy Biomarkers

Immune checkpoints dampen the immune system’s ability to detect and fight cancer; thus, inhibits of such checkpoints, usually antibodies to checkpoint factors, have utility for immunotherapy against cancer.  Clinical success has been varied, and it would be helpful to identify biomarkers to ascertain what patients would most benefit by this therapeutic approach.  This study identifies some prospective markers that require more conformation.  Abstract:

Immune checkpoint blockers (ICB) have become pivotal therapies in the clinical armamentarium against metastatic melanoma (MMel). Given the frequency of immune related adverse events and increasing use of ICB, predictors of response to CTLA-4 and/or PD-1 blockade represent unmet clinical needs. Using a systems biology-based approach to an assessment of 779 paired blood and tumor markers in 37 stage III MMel patients, we analyzed association between blood immune parameters and the functional immune reactivity of tumor-infiltrating cells after ex vivo exposure to ICB. Based on this assay, we retrospectively observed, in eight cohorts enrolling 190 MMel patients treated with ipilimumab, that PD-L1 expression on peripheral T cells was prognostic on overall and progression-free survival. Moreover, detectable CD137 on circulating CD8+ T cells was associated with the disease-free status of resected stage III MMel patients after adjuvant ipilimumab + nivolumab (but not nivolumab alone). These biomarkers should be validated in prospective trials in MMel. The clinical management of metastatic melanoma requires predictors of the response to checkpoint blockade. Here, the authors use immunological assays to identify potential prognostic/predictive biomarkers in circulating blood cells and in tumor-infiltrating lymphocytes from patients with resected stage III melanoma.

CDK8 Inhibitors And Cancer

CDK8 seems to have dual functions with respect to cancer, and investigating these roles, for potential therapeutic applications, will require CDK8 inhibitors.  This is how basic science intersects with the development of future therapies.  Abstract:

Cyclin-dependent kinase 8 (CDK8) plays a vital role in regulating transcription either through its association with the Mediator complex or by phosphorylating transcription factors. Myriads of genetic and biochemical studies have established CDK8 as a key oncogenic driver in many cancers. Specifically, CDK8-mediated activation of oncogenic Wnt-β-catenin signaling, transcription of estrogen-inducible genes, and suppression of super enhancer-associated genes contributes to oncogenesis in colorectal, breast, and hematological malignancies, respectively. However, while most research supports the role of CDK8 as an oncogene, other work has raised the possibility of its contrary function. The diverse biological functions of CDK8 and its seemingly context-specific roles in different types of cancers have spurred a great amount of interest and perhaps an even greater amount of controversy in the development of CDK8 inhibitors as potential cancer therapeutic agents. Herein, we review the latest landscape of CDK8 biology and its involvement in carcinogenesis. We dissect current efforts in discovering CDK8 inhibitors and attempt to provide an outlook at the future of CDK8-targeted cancer therapies.

Liver Cancer, Males Vs. Females, And ZebraFish

At left, adult female zebrafish. By Azul (Own work) [Copyrighted free use], via Wikimedia Commons

Liver cancer is more prevalent in men. There may be both biological and lifestyle reasons for this. To study possible biological mechanism, a zebrafish model was used. Abstract:

Hepatocellular carcinoma (HCC) is more prevalent in men than women, but the reason for this gender disparity is not well understood. To investigate whether zebrafish could be used to study the gender disparity of HCC, we compared the difference of liver tumorigenesis between female and male fish during early tumorigenesis and long-term tumor progression in our previously established inducible and reversible HCC model - the krasV12 transgenic zebrafish. We found that male fish developed HCC faster than females. The male tumors were more severe from the initiation stage, characteristic of higher proliferation, activation of WNT/β-catenin pathway and loss of cell adhesion. During long-term tumor progression, the male tumors developed into more advanced multi-nodular tumors, whereas the female tumors remain uniform and homogenous. Moreover, regression of male tumors required longer time. We further investigated the role of sex hormones in krasV12 transgenic fish. Estrogen treatment showed tumor suppressing effect during early tumorigenesis through inhibiting cell proliferation, whereas androgen accelerated tumor growth by promoting cell proliferation. Overall, our study presented the zebrafish as a useful animal model for study of gender disparity of HCC.

Obviously, humans are not zebrafish and it is not certain that the possible hormonal mechanism identified in the fish applies to humans, but it is a possible avenue for study.

Cancer Stem Cells And Lipid Metabolism

Cancer stem cells seem to have an increased reliance on lipid metabolism, which can be a target for anti-cancer therapy.  I wonder if this has any implications for a ketogenic (high-fat) diet for cancer?  On the one hand, most cancer cells seem “glucose-addicted” so a low-carb, high-fat diet may be preferable.  On the other hand, if cancer stem cells rely more on fat, then will increased dietary fat be a problem?  This question needs to be investigated.  Abstract:

BACKGROUND:

Cancer stem cells (CSCs) or tumor-initiating cells (TICs) represent a small population of cancer cells with self-renewal and tumor-initiating properties. Unlike the bulk of tumor cells, CSCs or TICs are refractory to traditional therapy and are responsible for relapse or disease recurrence in cancer patients. Stem cells have distinct metabolic properties compared to differentiated cells, and metabolic rewiring contributes to self-renewal and stemness maintenance in CSCs.

MAIN BODY:

Recent advances in metabolomic detection, particularly in hyperspectral-stimulated raman scattering microscopy, have expanded our knowledge of the contribution of lipid metabolism to the generation and maintenance of CSCs. Alterations in lipid uptake, de novo lipogenesis, lipid droplets, lipid desaturation, and fatty acid oxidation are all clearly implicated in CSCs regulation. Alterations on lipid metabolism not only satisfies the energy demands and biomass production of CSCs, but also contributes to the activation of several important oncogenic signaling pathways, including Wnt/β-catenin and Hippo/YAP signaling. In this review, we summarize the current progress in this attractive field and describe some recent therapeutic agents specifically targeting CSCs based on their modulation of lipid metabolism.

CONCLUSION:

Increased reliance on lipid metabolism makes it a promising therapeutic strategy to eliminate CSCs. Targeting key players of fatty acids metabolism shows promising to anti-CSCs and tumor prevention effects.

Cytoplasmic DNA And Metastasis

Chromosomal instability results in DNA in the cytoplasm, which is of course not normal, DNA being normally found only in the nucleus.  This misplaced cytoplasmic DNA triggers a pathway that simulates cell signaling that can promote metastasis.  This could in theory be targeted to inhibit metastasis (keep in mind that cancer mortality is for the most part due to metastasis).  Abstract:

Chromosomal instability is a hallmark of cancer that results from ongoing errors in chromosome segregation during mitosis. Although chromosomal instability is a major driver of tumour evolution, its role in metastasis has not been established. Here we show that chromosomal instability promotes metastasis by sustaining a tumour cell-autonomous response to cytosolic DNA. Errors in chromosome segregation create a preponderance of micronuclei whose rupture spills genomic DNA into the cytosol. This leads to the activation of the cGAS-STING (cyclic GMP-AMP synthase-stimulator of interferon genes) cytosolic DNA-sensing pathway and downstream noncanonical NF-κB signalling. Genetic suppression of chromosomal instability markedly delays metastasis even in highly aneuploid tumour models, whereas continuous chromosome segregation errors promote cellular invasion and metastasis in a STING-dependent manner. By subverting lethal epithelial responses to cytosolic DNA, chromosomally unstable tumour cells co-opt chronic activation of innate immune pathways to spread to distant organs.

p53 Inhibits CRISPR-Cas9 Engineering In Human Pluripotent Stem Cells

Human pluripotent stem cells are difficult to engineer with the CRSPR system compared to other cell types, which is unfortunate given the great potential in being able to modify human stem cells.  The p53 gene protects against cancer and it seems that p53 function interferes with CRISPR modification of these human stem cell types by making the genetic alterations induced by CRISPR relatively toxic to the cells.  Human stem cells can acquire p53 mutations – which can lead to cancer – and it would seem that human stem cells that have been successfully engineered with CRISPR may be at higher risk for having p53 mutations since the presence of such mutations, inactivating toxicity to CRISPR, may have been the reason the cells were successfully engineered in the first place.  This is an important finding suggesting caution in using CRISPR in such cells and also suggests the need to find novel approaches that can increase CRISPR efficiency in these cells while still maintaining p53 and its anti-cancer functions.  Abstract:

CRISPR/Cas9 has revolutionized our ability to engineer genomes and conduct genome-wide screens in human cells1-3. Whereas some cell types are amenable to genome engineering, genomes of human pluripotent stem cells (hPSCs) have been difficult to engineer, with reduced efficiencies relative to tumour cell lines or mouse embryonic stem cells3-13. Here, using hPSC lines with stable integration of Cas9 or transient delivery of Cas9-ribonucleoproteins (RNPs), we achieved an average insertion or deletion (indel) efficiency greater than 80%. This high efficiency of indel generation revealed that double-strand breaks (DSBs) induced by Cas9 are toxic and kill most hPSCs. In previous studies, the toxicity of Cas9 in hPSCs was less apparent because of low transfection efficiency and subsequently low DSB induction 3 . The toxic response to DSBs was P53/TP53-dependent, such that the efficiency of precise genome engineering in hPSCs with a wild-type P53 gene was severely reduced. Our results indicate that Cas9 toxicity creates an obstacle to the high-throughput use of CRISPR/Cas9 for genome engineering and screening in hPSCs. Moreover, as hPSCs can acquire P53 mutations 14 , cell replacement therapies using CRISPR/Cas9-enginereed hPSCs should proceed with caution, and such engineered hPSCs should be monitored for P53 function.

Cancer Immunotherapy: The Systemic Response

An article  on cancer immunotherapy; the abstract:

Immune responses involve coordination across cell types and tissues. However, studies in cancer immunotherapy have focused heavily on local immune responses in the tumor microenvironment. To investigate immune activity more broadly, we performed an organism-wide study in genetically engineered cancer models using mass cytometry. We analyzed immune responses in several tissues after immunotherapy by developing intuitive models for visualizing single-cell data with statistical inference. Immune activation was evident in the tumor and systemically shortly after effective therapy was administered. However, during tumor rejection, only peripheral immune cells sustained their proliferation. This systemic response was coordinated across tissues and required for tumor eradication in several immunotherapy models. An emergent population of peripheral CD4 T cells conferred protection against new tumors and was significantly expanded in patients responding to immunotherapy. These studies demonstrate the critical impact of systemic immune responses that drive tumor rejection.

In other words, a local response at the tumor by the immune system is sufficient for sustained proliferation of the immune response required for tumor rejection.  A (body-wide) systemic immune response is required, a set of responses that, as the article states "involve coordination across cell types and tissues."

It would stand to reason, as my hypothesis, that those things that would enhance the overall function of the immune system - diet, exercise, proper sleep,  less stress, and possibly the gut microbiota - would assist the body in generating the systemic responses required for tumor rejection.  More studies are required to evaluate my hypothesis.