# HCC Pathogenesis In NASH & The Impact Of Fibrosis (Hepatocellular Carcinoma) | Dr Scott L. Friedman

https://www.youtube.com/watch?v=_ZYlF91FmWk

[00:05] Hello, this is Dr. Scott Friedman at the Icon School of Medicine at Mount Sinai.
[00:10] I'm delighted to give this lecture on behalf of the Pan Nash initiative.
[00:15] My title is the HCC pathogenesis in Nash and the impact of fibrosis.
[00:20] And this is adapted from a lecture I gave recently to the Paris Nash meeting, and I'm pleased to illustrate the highlights of that topic in this talk today.
[00:28] I have many commercial interactions, none of which are related directly to the content of this talk, but I list them for completeness sake.
[00:35] Here's the overview of my lecture.
[00:37] I will cover three areas of HCC, fibrosis, and Nash.
[00:42] First is epidemiology and clinical features.
[00:45] Secondly, I will talk about HCC mechanisms that are unique to NAFLD or non-alcoholic fatty liver disease and not dependent on fibrosis.
[00:55] And finally, I will close with some potential mechanisms that link fibrosis directly to Nash hepatocellular carcinoma.
[01:01] To remind the audience, this is the spectrum of non-alcoholic fatty liver disease.
[01:06] Includes patients with fat alone known as non-alcoholic fatty liver.
[01:11] Up to 40 percent of Americans have this condition, of whom 25 progress to this state of non-alcoholic steatohepatitis.
[01:20] This is the disease stage at which there is great attention being focused, both because of its risk of inflammation and progressive fibrosis and cirrhosis shown here, but also because of the risk of hepatocellular carcinoma.
[01:35] I will also emphasize very shortly the unique feature of HCC and Nash, which suggests that up to a third of patients will develop hepatocellular carcinoma while they still have Nash but before they have developed cirrhosis.
[01:47] So we need to be vigilant about the risk of HCC earlier in the stages of disease for underlying Nash compared to viral hepatitis.
[01:57] This slide illustrates the compelling epidemiologic data of HCC prevalence rising relative to the underlying.
[02:07] Etiologies including chronic Hepatitis B, chronic hepatitis C, alcoholic liver disease, or alcohol plus chronic Hepatitis C.
[02:15] What is clear from the purple line is that relative to other underlying causes of HCC, the number or fraction of patients or the relative rise associated with non-alcoholic fatty liver disease is disproportionately greater.
[02:30] So over time, an increasing fraction of our patients with primary liver cancer or HCC will have underlying NAFLD or NASH.
[02:38] And this represents an important epidemiologic milestone that tells us we need to understand the disease better in order to intervene early and ultimately to develop more effective treatments.
[02:49] This slide from a recent review from my colleague Dr. Joseph Lavette underscores the global incidence of NASH HCC per 100,000 people, with the darker blue representing the higher global incidence.
[03:01] As one can see, particular regions including China and Mongolia where co-infection.
[03:08] With hepatitis B and Delta is particularly high, but also Middle East and North Africa, in particular Egypt.
[03:15] So disease is distributed differentially around the world, but is increasing in all these regions.
[03:20] Now, one of the key points that I mentioned is that unlike hepatitis C, B, and other diseases, NAFLD has an underlying etiology is associated with a higher fraction of patients who are not yet cirrhotic.
[03:34] So what you're looking at here is the relative distribution of cirrhosis in the darker gray and non-cirrhotic in the lighter gray, again for hep C, B, and alcohol.
[03:44] Almost over 90 percent in most cases of the cancers that arise do so after the patient has cirrhosis.
[03:52] Whereas in NAFLD, up to a third of patients develop these cancers before they are cirrhotic.
[03:56] And this illustrates some important concepts.
[03:58] First of all, in NASH, it's clear that other factors beyond fibrosis alone contribute to HCC, and it begs the question of what are these factors.
[04:08] So before we focus on the.
[04:10] Factors apart from cirrhosis, it is worth re-emphasizing that still cirrhosis is the strongest risk factor for HCC.
[04:18] Methyl D overall cirrhosis, shown here as an incident rate, also linked to a higher incidence in males, which is well known.
[04:26] Hispanic ethnicity, and this is interesting because it's almost surely related in part to the high prevalence of the BLA3 polymorphism, as I'll describe in a moment, that is higher in Latino Americans.
[04:36] Also, the presence of diabetes is another heightened risk factor for cirrhosis in addition to hepatocellular carcinoma.
[04:45] So there are some identifiable risk factors epidemiologically, but also there are HCC mechanisms that are unique to NAFLD and non-fibrosis dependent.
[04:54] In particular, the prevalence of obesity in patients with NAFLD represents a significant risk factor for all cancers, but in particular liver cancer.
[05:04] This is a study from over 10 years ago from Doctors Oberianasi looking at the type of cancer that's.
[05:12] Impacted by prevalence of obesity.
[05:15] What you can see in the red boxed area is among the different cancers where obesity is a risk factor.
[05:19] That risk is heightened to the greatest extent for liver cancer.
[05:23] And so clearly obesity is creating some metabolic conditions that give rise or predispose to liver cancer.
[05:30] And of course in some ways it makes sense that that's greatest in liver compared to other organs because so much of the metabolic work of the system and the storage of fat takes place in the liver.
[05:40] But there are other mechanisms of increased risk of cancer associated with obesity that are especially relevant to primary liver cancer.
[05:46] Obesity itself is a chronic inflammatory state with more oxidant stress, DNA damage, and mutations cause of chronic damage and DNA injury.
[05:59] Secondly, with an increased fat burden in obesity there is increased estrogen production.
[06:04] And this may also drive the emergence of neoplasia more precipitously in liver than other organs.
[06:13] Associated with this is a higher circulating level of insulin like growth factor in insulin which are thought to be modestly pro-carcinogenic.
[06:22] And more broadly there's an increase in all adipocytes especially leptin which is a mitogen in liver and so higher fat means higher leptin and higher leptin is a higher mitogenic signal.
[06:32] There are clearly genetic risk factors which I'll review in just a moment.
[06:37] And finally we shouldn't overlook the emerging importance of the altered gut microbiome.
[06:41] It's very clear that the microbiome is an important determinant to both of disease and also of Nash in particular NHCC.
[06:49] And elegant studies in animals show that Nash itself can be transmissible through a gut microbiome transplant.
[06:57] And we know that patients who are at higher risk for cancer have a unique microbiome.
[07:01] And the challenge now is to begin to harness the information from that microbiome both diagnostically but also mechanistically to understand what it is about the features of the microbiome that predisposed to either Nash or.
[07:14] Cancer and to try to mitigate those therapeutically in addition to using it as a diagnostic tool.
[07:18] And so we have a lot to learn about the link between obesity, gut microbiome, and these other features.
[07:25] But each of them represent potentially actionable points of pathogenesis that we have to understand better.
[07:32] In addition, it's very clear that the immune microenvironment in NASH is unique compared to other chronic liver diseases and creates a permissive microenvironment for cancer.
[07:42] This is summarized in another review by Dr. Lovett that indicates the presence of chronic dyslipidemia that ultimately can change the generation or increase the generation of reactive oxygen species, deplete protective CD4 cells, and increase TH17 cells.
[07:58] And this can also lead to neutrophil activation and changes in this in the cytoplasm and nuclei and mitochondria which collectively represents stress to the cell that may be unique to the NASH pathogenesis and all of these elements.
[08:16] Metabolic reprogramming increased in the endoplasmic reticulum stress and mitochondrial stress are thought to be stressors to the cell that can predispose to DNA damage, loss of protective abilities of the cell, and ultimately the emergence of a small cancer.
[08:32] The importance of the microenvironment in NASH and the difference in this microenvironment compared to other etiologies was underscored by a very elegant paper published in Nature last year, in which the investigators looked at the outcomes treatment with the newly emerging immune checkpoint inhibitors and compared those outcomes between those patients who had NAFLD and those patients who had other etiologies, almost highly viral hepatitis.
[08:59] You're looking here at the overall survival curves in a discovery cohort in B and a validation cohort in C.
[09:07] In each case, the group with other etiologies had a better overall survival following checkpoint inhibitor treatment compared to the patients with underlying NAFLD.
[09:17] Shown in blue both in the discovery and the validation cohort, so we'd suggest that there is a different microenvironment in the immune system in NAFLD compared to other etiologies.
[09:29] This is an area of intense interest and investigation.
[09:32] At the stage of this paper, the authors conclude that there may be NASH-related aberrant T-cell activation that causes tissue damage and leads to impaired surveillance.
[09:40] So we are continuing to dig deeper into understanding the unique features of the immune microenvironment in hopes that we can harness that information to develop more personalized therapies that are NASH-specific and that have a greater efficacy than the current immune checkpoint inhibitors.
[09:59] I also alluded earlier to the importance of genetics to the incidence of NASH HCC.
[10:03] And I illustrate here data from some time ago from the group of Helen Reeves and University of Newcastle looking at the rising incidence of HCC within their region in Northeast England, but more importantly, the rising fraction of the.
[10:19] Overall number of cases that were attributable to NAFLD shown here in orange.
[10:22] So what you can see, sorry, what you can see overall is that not only was there an increase in number of referrals, which was expected, but also the overall fraction of those cases that had other, flying NAFLD also increased.
[10:38] And even at this 12 years ago, NAFLD already accounted for almost 35 percent of their cancers.
[10:42] And again, the point that up to almost a third did not have underlying cirrhosis.
[10:46] And this is a finding that's been replicated now at least three times, that the fraction of non-cirrhotic HCC is greater than other etiologies.
[10:55] But the key point I want to emphasize in this slide is if the risk associated variant in this gene, PNPLA3, was present, and particularly if it was homozygous, the odds ratio for the development of cancer was almost 13.
[11:11] So it suggests again that polymorphisms in different genes, some of which are clustered ethnically or genetically, also predisposed to or.
[11:19] Create a setting right for the development of HCC.
[11:21] There are in fact a number of polymorphisms that are linked to Nash HCC.
[11:25] A partial list is shown here, also from another review from Dr. Lovat.
[11:31] I'm not going to go through these individually, but will point out that in virtually all cases they relate to polymorphisms that somehow regulate or alter metabolism of lipids, either export, synthesis, content.
[11:45] And this suggests that changes in the amount of fat that's accumulated based on genetic risks may also have downstream effects on the development of injury and also other factors related to fat accumulation that can drive the emergence of hepatocello carcinoma.
[12:02] And so we over time will begin to integrate this genetic information to calculate more robust risk scores combined with other features of Nash to predict who will develop Nash HCC.
[12:12] This is important because it may inform our screening efforts so that patients who have a high...
[12:19] Genetic risk associated with liver fat could require more stringent and earlier screening for HCC to identify and treat cancers when they are still curable.
[12:29] I'll just say a word about experimental models.
[12:31] These represent a mainstay overall for our first to understand Nash HCC.
[12:36] My own laboratory developed a model described here that we now call the fat Nash model.
[12:41] Fat is stands for fibrosis and tumors which we think is an important component of the model.
[12:48] These animals are given a high fat, high cholesterol, high fructose diet with a very low dose of ccl4 carbon tetrachloride intraperitoneally.
[12:55] And what you can see is in the animals that receive both the Western diet and ccl4 there's a dramatic increase in the number of tumors and in the immune tumor size.
[13:05] Those tumors can be quite large and appear on the surface of the liver.
[13:10] Here you're looking at a tumor liver interface, the Nash liver on the left, the tumor on the right.
[13:17] And in studies that are still ongoing we and others are exploring the possibility but senescence.
[13:21] Of cells indicated here by expression of beta galactosidase activity in blue.
[13:26] That's in essence of cells in particular stellate cells, which I'll review in a second, can ultimately represent some kind of risk for a hepatocellular carcinoma.
[13:34] I would mention also that what's exciting about our fat NASH model is that in addition to the liver disease which we are studying extensively, we now have evidence that they develop renal disease that includes glomerulosclerosis and interstitial fibrosis.
[13:47] And these are ongoing studies done in collaboration with our chief of nephrology here at Mount Sinai.
[13:51] But it does suggest that the model may be a useful one not only for liver disease but also for the metabolic syndrome-associated changes that occur in kidney and perhaps in heart and blood vessels as well.
[14:02] So let me spend the last remaining few minutes talking about the presence of fibrosis and how that may impact on NASH HCC.
[14:09] This is a very comprehensive table that illustrates the molecular differences between NASH HCC and non-NASH HCC in each case NASH HCC.
[14:21] Is on the left, and so starting with the etiology, of course, NASH HCC is associated with obesity, diabetes, dyslipidemia, metabolic syndrome.
[14:31] And the non-NASH is primarily attributable to underlying infection as well as alcohol.
[14:35] In terms of the molecular alterations, there's been now extensive characterization suggesting that in NASH HCC, a smaller fraction of the tumors have dysregulation of the Wnt beta-catenin subclass, which is CTNNB1.
[14:50] Whereas non-NASH HCC has a higher fraction of tumors that have dysregulation of Wnt beta-catenin.
[14:58] And the SNPs that I described in the previous slide are also more prevalent in NASH HCC than non-NASH HCC.
[15:05] In terms of the immune phenotype, I've already emphasized we think this is quite different in the underlying NASH that gives rise to HCC.
[15:11] And that includes many of these features here of activated dysfunctional immune cells as well as NK cells and elevated Th17 cells that disrupt tumor surveillance, and again the...
[15:22] Key point that there's a decreased incidence of underlying cirrhosis in Nash HCC air through non-nash HCC.
[15:29] Interestingly, alcoholic cellular hepatitis in more recent studies also has a high, higher fraction of non-serotic HCC, but not as high as those who have Nash.
[15:39] And remember also the presence of Nash and Ash together is not uncommon, and so presumably this is a synergistic interaction that accelerates the emergence both of Nash but also inflammation, fibrosis, and cancer when both Nash and Ash are present in the same patient.
[15:58] As many may know, my own laboratory has focused for almost 40 years on the pathogenesis of Nash, or fibrosis I should say, and in particular the role of the hepatic stellate cell.
[16:09] The hepatic steli cell, shown here in blue, is a resident non-parenchymal, non-hypatocyte cell in the liver located between hepatocytes and sinusoid endothelial cells.
[16:19] It is in fact a parasite of the liver that wraps its.
[16:23] Foot processes around the sinusoid and its most characteristic feature is the storage of droplets of vitamin A in the form of retinal esters.
[16:33] As the cells activate, shown here, those retinal esters are lost and the cells begin to multiply associated with accumulation of scar or interstitial collagen and resulting in changes in the function of surrounding cells.
[16:47] In particular, loss of hepatocyte differentiation, closure of the pores in the sinusoidal endothelial cells or fenestrae that normally constitute a healthy sinusoid, and activation of macrophages.
[16:59] And so our studies have focused for decades on how activation occurs and, of course, how it ultimately can be mitigated to reduce fibrosis therapeutically.
[17:07] The role of these stellate cells in tumor emergence, both primary and probably metastatic tumors, is multi-fold.
[17:14] Stellate cells, which also are known as cancer-associated or tumor-associated fibroblasts, CAFs or TAFs, play a central role in integrating.
[17:24] Signals both from damage to hepatocytes that include hypoxia but also interactions with endothelial cells as well as different immune cell subsets and collect actively stellate cells help orchestrate both the angiogenic fibrotic as well as the inflammatory responses that underlie tumor growth and proliferation.
[17:43] We summarized some time ago the potential pathways and links between fibrosis and HCC.
[17:47] I refer you to this reference song at all from 10 years ago which fundamentally is still accurate in terms of the concepts we outlined.
[17:56] Time does not permit me to go through all of these, but there are certainly pathways that go from normal liver to chronic inflammation.
[18:02] Other pathways that underlie the emergence of hepatocellular carcinoma directly from the inflammatory liver but also through myofibroblasts or stellate cell activation that generates fibrosis and lead to a number of other features that also contribute.
[18:20] And let me just illustrate one or two of these.
[18:21] For one thing, it turns out that stellate cells.
[18:25] Are as I mentioned a nodal point regulating immunology, immune responses, and inflammation in a way that may promote HCC growth.
[18:36] That's summarized in this slide here where you're looking at an activated stellate cell and all of the different ways that stellate cells can amplify inflammation.
[18:44] I'll emphasize for the purpose of this talk there are a couple of specific pathways that are emerging and in particular that stellate cells can enhance myeloid derived suppressor cells and suppress T and B cell via PDL1 which are expressed on stellate cells.
[18:59] And this effectively can lead to a more immunotolerant environment so that the immune system does not attack and clear nascent tumors.
[19:05] So in a sense the immuno tolerance of the liver which is largely attributable to activation of stellate cells also creates a permissive environment in which the immune system can no longer surveil the tumors or surveil the tissues accurately drive the immune system to clear early tumors.
[19:23] I also mentioned earlier the importance or the.
[19:25] Emerging importance of a senescence-associated secretory phenotype or SAS.
[19:28] Several studies done years ago underscored the potential role specific typically of stellate cells becoming senescent and driving the development of a pro-termogenic environment.
[19:40] This is linked in at least in one study from Japan to a high fat diet, a change in the microbiome, and elaboration of the oxycolic acid that drives the senescent microenvironment and liver.
[19:52] So this is an exciting potential area of interaction where the gut changes in the microbiome leads to changes in the necessity in the senescence microenvironment that develop into liver cancers.
[20:03] One exciting study performed by the laboratory of Dr. Scott Lowe, we participated peripherally in this study in which they reasoned that if they could clear the senescent stellate cells then perhaps that would have an impact on fibrosis.
[20:19] And they did this by generating specialized focused CAR or chimeric antigen receptor T cells.
[20:25] that were conditioned or generated to
[20:28] identify a very specific Target that's
[20:30] only expressed on senescent Stella cells
[20:33] and that's your kinase plasminogenic
[20:34] activator in this study published in
[20:36] nature two years ago they gave ccl4 to
[20:39] develop fibrosis they've also done this
[20:41] with a Nash model at six weeks into the
[20:43] injury they administered very
[20:45] specialized T cells to kill any stellate
[20:48] cell that was senescent marked by the
[20:50] expression of urokheisman your kinase
[20:52] plasmination activator and these results
[20:54] were really quite striking when they
[20:56] cleared senescent stellate cells on the
[20:58] right based on serious red staining
[21:00] there was a dramatic diminution in
[21:01] fibrosis content Quantified here in the
[21:04] lower left but in addition when they
[21:06] used beta gal activity staining to
[21:09] identify senescent cellulate cells it
[21:11] was a dramatic diminution in beta gal
[21:13] expressing cells suggesting that indeed
[21:16] their car T cells that so effectively
[21:18] are successfully cleared those in
[21:20] essence delicate cells but they also
[21:22] showed which I find a particularly
[21:23] interesting and exciting is that as they
[21:25] cleared senescent stellate cells liver
[21:27] function improved and serum albumin
[21:29] almost doubled and this suggests an
[21:32] important link that we don't understand
[21:34] well between fibrosis and regeneration
[21:37] the more fibrosis the less regeneration
[21:39] in this case once you clear senescent
[21:41] pro-fibrotic stellate cells regeneration
[21:44] may be Amplified and that's reflected in
[21:46] the rise in serum albumin in these
[21:48] animals in addition although I won't
[21:50] illustrate it for lack of time cellulite
[21:52] cells and hepatocytes in the
[21:53] microenvironment can interact with
[21:55] Matrix bound growth factors as the scar
[21:58] accumulates a number of growth factors
[22:00] are Tethered to that Scar and can be
[22:03] released as stellate cells activate
[22:05] further and ultimately Drive replication
[22:08] and proliferation of hepatocytes and the
[22:10] emergence of cancer so there are both
[22:12] immune but also physical and cytokine
[22:15] driven interactions between stellate
[22:17] cells in the environment they create and
[22:19] the emergence of liver cancer and
[22:21] pre-neoplastic hepatocytes so this gives
[22:24] me an opportunity to summarize the key
[22:25] points I've been trying to make in the
[22:27] last few minutes first of all systemic
[22:29] effects of obesity on cancer development
[22:32] are especially relevant to liver and
[22:33] involved inflammation genetics growth
[22:36] factors adapokines and microbiome among
[22:39] others and I've given you several
[22:41] several illustrations the immune milieu
[22:43] of Nash is distinct and may be
[22:45] immunotolerant and thereby diminishing
[22:48] responses to checkpoint Inhibitors so
[22:50] work needs to be done on defining the
[22:52] specific immune deficits in the Nash
[22:54] liver so that we can establish more
[22:57] personalized or Precision therapies that
[23:00] attack the immune dysregulation that's
[23:02] unique to Nash finally mechanisms
[23:04] linking fibrosis to HCC and Nash include
[23:07] actions of hepatic stellate cells as
[23:09] modulators and orchestrators of immunity
[23:11] and inflammation but also the physical
[23:13] features of the extracellular Matrix
[23:15] their ability to bind growth factors and
[23:17] also the potential stiffness of the
[23:20] liver that occurs as fibrosis progresses
[23:22] and in the last Point as we develop and
[23:26] approve Nash therapies and anti-fibrotic
[23:28] treatments we should explore their
[23:30] impact on these putative mechanisms of
[23:33] HCC in the hope and expectation that
[23:35] anti-fibrotic therapies will not only
[23:37] improve and reduce the risk of liver
[23:40] failure but will also attenuate the
[23:42] emergence of liver cancer so with that
[23:45] I'll close thank the pat Nash Initiative
[23:47] for the opportunity to present this
[23:49] lecture which I hope you find
[23:50] informative thank you
[23:53] [Music]
[24:06] foreign