1. Introduction
Self-regulation of an animal organism, also-called homeostasis, depends on several factors. At a macroscopic scale, pH, temperature, the amount of oxygen and carbon dioxyde in the blood and so on in living organisms self-adjust to fight against threats present in the environment and keep a stable physiology.
In mammals, the main organs involved in homeostasis are the hypothalamus that controls body temperature and circadian cycles, the pituitary gland that rates the secreting hormones, the lungs that regulate the balance between blood oxygen and the carbon dioxide, the skin that protects against outer pathogens, the muscles in the circulatory, gastrointestinal and blood systems, the kidneys that regulate water and salts in the blood and the amount of urine thanks to hormones, the liver which acts as a factory for bile, glucose, hemoglobin, ammonia and toxins, the pancreas that produces the hormones and enzymes for digestion and finally the brain that controls behavior whether conscious or unconscious. Such macroscopic features of homeostasis are well summarized by Claude Bernard in his 19th-century lectures [
1].
A genome-scale homeostasis exists as well. Gene expression (GE) is the process by which information from a gene is used to synthesize end products such as proteins or non-coding RNA. GE is the most fundamental level at which the genotype gives rise to observable traits called the phenotype. At all steps, GE is regulated by transcription, translation and post-transcriptional changes in the production of proteins. Such microscopic homeostasis for creating messenger mRNA is a complex machinery that makes use of non-coding genes transcribed as precursors that undergo further processing [
2].
Rules for genome scale homeostasis similar to the constancy rules of macroscopic homeostasis are not yet firmly established. We mention previous work in this direction [
3,
4,
5]. In our previous publications we started to unveil some of these rules by using a group theoretical approach. Since the genome is digital with its four nucleotides A, U/T, G and C as letters, there are important short sequences as the consensus sequence of a transcription factor, a TATA box, a polyadenymation signal or a microRNA (miRNA) whose structure should obey group theory and associated character variety rules. Otherwise, a disease is in sight [
6,
7,
8]. Chemical modifications in the environment also controls the metabolism of GE. For instance, RNA methylation with
-methymadenosine (
) is documented in our recent paper [
8].
For studying the aforementioned key sequences, we employ infinite (finitely generated) groups denoted by
, and their representations over the matrix group
, where the entries of matrices are complex numbers [
6]. The importance of this group extends across all fields of physics as it represents a space-time-spin group.
Our crucial observation is that an
group associated with a “healthy” sequence usually approximates a free group
, where the rank
r equals the number of distinct nucleotides minus one. A sequence deviating from this may suggest a potential dysregulation leading to a disease. However, an
group closely resembling a free group does not provide sufficient assurance against a disease. Additional examination of the
representations of
termed the character variety, specifically its Groebner basis
, is necessary. The Groebner basis comprises a set of surfaces. A surface within
containing isolated singularities indicates a potential disease that can be identified specifically, e.g., relating to an oncogene or a neurological disorder [
6] [Figure 6, Tables 2 to 4].
An additional attribute of “healthy” sequences, which leads to a group
approximating the free group
and not mentioned in [
6], is their connection to aperiodicity. Schrödinger’s book [
9] proposes aperiodicity of living “crystals”. Our papers [
7,
8] characterize some aperiodic DNA/RNA sequences. But in this paper we do not focus on this aspect of genome scale homeostasis.
Our new goal in the current paper is to feature the dynamical equations sustaining some of the algebraic surfaces contained in the Groebner basis attached to the group
of the considered short sequence. This task was started in [
10] using the list of algebraic solutions of Painlevé VI (PVI) equation [
11]. We made use of the PVI equation and the cubic algebraic surfaces contained in its character variety in the context of miRNAs. We continue along these lines by looking at cubic surfaces contained in the character variety of Painlevé equations of lower index such as PV and PIV. As explained below, this is a crucial step since the topology of the character variety of PV and PIV is wilder than that of PVI, the singularities of the corresponding surfaces are more irregular than those with PVI [
12,
13]. The occurrence of surfaces related to PV and PIV may signify a more severe disease than a surface related to PVI.
In
Section 2, we investigate the topology of Painlevé equations and their related character variety. We also remind readers how the character variety of a group
may contain simply singular surfaces of the Painlevé type. In
Section 3, we apply these techniques to miRNAs recognized as oncomirs or tumor supressors. Our results are in accordance with our aforementioned view of health versus disease.
Section 4 summarizes our approach.
3. Results and Discussion
The theory developed in the previous section is applied to sequences determined by the seed of a miRNA. Animal miRNAs are able to recognize their target mRNAs by using as few as 6 to 8 nucleotides (the seed region) at the 5’ end of the miRNA (for a -5p strand) or at the 3’ end of the miRNA (for a -3p strand). A given miRNA may have hundreds of different mRNA targets, and a given target might be regulated by multiple miRNAs. Thus it is not surprising that a simple correlation between a miRNA and a disease cannot be found. In the following, the selected miRNAs occur in the context of cancer research [
23]. We mention that there are repositories where useful links between diseases and non coding RNAs such as miRNAs are listed [
24,
25] [Table 1]. The seeds used for our calculations of the group
are taken from [
26,
27].
Our results are summarized in
Table 1 for miRNAs generally considered as oncomirs and
Table 2 for miRNAs generally considered as tumor suppressors. Of course the boundary between the two types is not sharp and depends on the type of disease under examination. We remind readers from the introduction that dysregulation may occur when either the
group generated by the seed sequence is away from the free group
(for a seed with two distinct nucleotides), away from the free group
(for a seed with three distinct nucleotides) or away from the free group
(for a seed with three distinct nucleotides). The number of conjugacy classes of subgroups of a given index for the group
is abbreviated as `card seq’. The first step is to check if the card seq is close to that of a free group
,
, 2 or 3 or not. In the later case, the sequence may predict a risk of disease.
The second step is to check the structure of the character variety associated to
, more precisely the structure of its Groebner basis
. We focus on cubic surfaces belonging to
and, if they contain an isolated singularity, we determine the A-D-E type (abbreviated as ADE type). From the introduction we claim that dysregulation may occur if such an isolated singularity exists in a cubic surface in
. Finally, we can check if the simply singular surface belongs to the Painlevé class (PVI, PV or PIV). E.g. in
Table 1, the notation
: PVI means that the Cayley cubic of ADE type
is a solution of equation
associated to the character variety of PVI whose topology is the 4-punctured sphere (as in
Figure 1). In
Table 1, the notation
: PV for the surface
means that the ADE type is
and that the surface is associated to PV equation.
All oncomirs in
Table 1 have an
such that the corresponding
contains simply singular cubic surfaces whatever the card seq of
is that of a free group or not. Thus a) correlation between our approach and the risk of the disease is well established.
In
Table 2, only five miRNAs generally considered as tumor suppressors have an
either away from the free group
or with a
containing simply singular cubic surfaces. The remaining miRNAs have an
like the free group
and show no simply singular surface in
. It is well known that a microRNA may act as an oncogen for a given type of cancer or as a tumor suppressor for another type. E.g. let-7a-5p is a regulator for tumors in many cancers but may also unfavorable in lung cancer.
We do not investigate miRNA seeds comprising 4 distinct nucleotides. It is straightforward to check if the corresponding
group is close to the free group
or not and if the seed sequence is aperiodic or not. But the Groebner basis is more difficult to obtain and its structure does not allow us to differentiate between `healthy’ and `disruptive’. Further progress is necessary [
10] [Section 5.1].
Details and references for each considered miRNA are given in the subsections below. Most cubics appearing in the Groebner basis attached to the group of the seed are degree 3 Del Pezzo surfaces (denoted as DP3).
Table 1.
A partial list of miRNAs generally considered as oncomirs.
Table 1.
A partial list of miRNAs generally considered as oncomirs.
ine
oncomir |
seed |
card seq |
sing type |
Cancer type |
ine
miR-21-3p |
aacacca |
not
|
,
|
ubiqitous |
miR-204-5p |
ucccuuu |
not
|
,
|
prostate |
miR-126-5p |
auuauua |
|
|
liver |
miR-1908-5p |
ggcgggg |
|
: PVI |
ubiquitous |
miR-1908-3p |
cggccgc |
|
,
|
breast |
ine
miR-155-3p |
uccuaca |
not
|
,
|
ubiquitous |
miR-9-5p |
cuuuggu |
|
: PV, PVI |
metastasis |
miR-146b-3p |
cccugug |
not
|
}: PV |
pancreatic |
miR-19a-5p |
guuuugc |
|
, , PVI
|
pancreatic |
miR-181a-5p |
acaucaa |
|
,
|
ubiquitous |
miR-15-5p |
agcagca |
|
: PV |
prostate |
miR-569 |
guuaaug |
not F2 |
|
lung, breast |
miR-133b |
uuggucc |
not
|
, ,
|
ubiquitous |
miR-1270 |
uggagau |
|
|
osteosarcoma ine |
Table 2.
A partial list of miRNAs generally considered as tumor suppressors. According to our view, as well as the references given in the text, the first five miRNAs behave more likely as oncomirs.
Table 2.
A partial list of miRNAs generally considered as tumor suppressors. According to our view, as well as the references given in the text, the first five miRNAs behave more likely as oncomirs.
ine
tumor suppressor |
seed |
card seq |
sing type |
Cancer type |
ine
miR-let-7a-5p |
gagguag |
|
,
|
ubiquitous |
miR-let-7a-3p |
uauacaa |
|
no cubic |
ubiquitous |
miR-34b-3p |
aaucacu |
not
|
, ,
|
lung, breast |
miR-200a-5p |
aucuuac |
not
|
,
|
skin, colorectal |
miR-22-5p |
guucuuc |
|
|
nsc lung |
miR-214-5p |
gccugu |
|
|
ubiquitous |
. |
gccuguc |
|
no cubic |
. |
miR-214-3p |
cagcag |
|
|
. |
. |
cagcagg |
|
no cubic |
. |
ine
miR-503-5p |
agcagcg |
|
rational scroll |
colon |
miR-141-5p |
aucuucc |
|
no cubic |
blood leukemia |
miR-31-5p |
ggcaaga |
|
rational scroll |
oral |
miR-122-5p |
gagugug |
|
no cubic |
ubiquitous |
miR-29b-5p |
cugguuu |
|
no isol. sing. |
head, neck |
miR-143-3p |
gagauga |
|
no cubic |
pancreatic |
miR-140-5p |
agugguu |
|
no isol. sing. |
colorectal |
miR-340-5p |
uauaaag |
|
no cubic |
ubiquitous |
miR-340-3p |
cguucuc |
|
no cubic |
ubiquitous |
miR-27-5p |
cugucug |
|
no isol sing. |
Wilms’ tumor |
miR-27-3p |
acagcaa |
|
no cubic |
cervical ine |
3.1. Human microRNAs That Mainly Act as Oncomirs
In this subsection, we provide details about the results summarized in
Table 1. The first five miRNAs have two disinct nucleotides in their seed. Their card seq may be that of the free group
of rank one or correspond to a group away from
. All of them have a Groebner basis containing DP3 simply singular cubic surfaces. The other selected oncomirs have three distinct nucleotides in their seed. Their card seq may be that of the free group
of rank one or correspond to a group away from
. All of them have a Groebner basis containing DP3 simply singular cubic surfaces. Some of the surfaces correspond to a Painlevé equation PVI (PVI
means that we are dealing with an algebraic solution of PVI), some surfaces correspond to PV equation. These results confirm our approach that a disease is in sight when either the card seq is away from a free group or the Groebner basis contains surfaces with isolated singularities. As already mentioned, PV is a wilder singular form than PV and we can expect a more severe disease in this case.
The Oncomir miR-21-3p
The clinical importance of miR-31-3p in human cancers was investigated in [
28]. miR-21 expression is different among cancers and the expression level of miR-21 is primarily increased to promote tumor progression. Upregulation of miR-21 results in drug resistance and radio-resistance in various cancers.
The seed aacacca of miR-21-3p contains two distinct nucleotides a and c. The associated card seq is the sequence
that is away from that of the free group
. According to our approach, this feature may be associated to a disease. The Groebner basis associated to the character variety of the seed is simple enough to merit an explicit display as
The two cubic surfaces defining
are degree 3 Del Pezzo (DP3) of the ADE type
and
(shown in
Figure 2: Left). The third factor is a curve and the last one is a quadric not playing a role in our singularity analysis.
The Oncomir miR-204-5p
Abnormal expression of miR-204-5p plays a contrasting role in cancer [
29,
30]. A decrease expression often due hypermethylation favors the progression of tumors while an increase expression may also be associated to prostate, breast or ovarian cancers. But miR-204-5p also has a role in a variety of tumors by regulating metastasis and apoptosis.
The seed ucccuuu of miR-204-5p contains two distinct nucleotides u and c. The associated card seq is the sequence
that is away from that of the free group
. According to our approach, this feature may be associated to a disease. The Groebner basis associated to the character variety of the seed is simple
The three cubic surfaces defining
are DP3 of the type
,
and
(shown in
Figure 2), respectively.
The Oncomir miR-126b-5p
MicroRNA miR-126b-5p promotes tumor cell proliferation, metastasis and invasion by targeting the enzyme TD02 in hepatocellular carcimona, one of the most common gastrointestinal malignancies, with the third highest mortality rate [
31].
The seed auuauua of miR-204-5p contains two distinct nucleotides a and u. The associated card seq is the sequence
which corresponds to the modular group, denoted
. According to our approach, this feature may be associated to a disease. The Groebner basis associated to the character variety of the seed
The first threee cubic surfaces defining are DP3 of the type (an isolated singularity of the ADE type ) or (an isolated singularity of the ADE type ). The last two cubic surfaces are rational scrolls devoid of an isolated singularity.
The Oncomir mir-1908
miR-1908-5p is aberrantly expressed in many diseases, especially cancer, being widely involved in a variety of cellular behaviors, including cell proliferation, cell differentiation, apoptosis, cancer cell invasion and metastasis, and extracellular vesicle secretion [
32]. miR-1908-3p promotes the breast cancer cells proliferation and metastasis by suppressing several genes [
33]. miR-1908 is also involved in the pathoetiology of bipolar disorder, myocardial infarction, obesity, renal fibrosis, rheumatoid arthritis and scar formation [
34].
The seed ggcgggg of miR-1908-5p contains two distinct nucleotides c and g. The associated card seq is that of the free group with a single generator. The attached Groebner basis contains the Cayley cubic : PVI.
The seed cggccgc of miR-1908-3p contains two distinct nucleotides c and g. The associated card seq is that of the group already encountered for mmiR-126-5p. The attached Groebner basis contains DP3 surfaces of ADE type and .
The Oncomir miR-155-3p
mir-155 is a key miRNA in both immunity and cancer and its miRNA strand, miR-155-3p, has been functionally implicated in both areas despite its low abundance (about 2%) compared to the -5p strand. An increased miR-155-3p strand percentage in cancerous tissues may indicate a specific dysregulation of mir-155 [
35].
The seed uccuaca of miR-155-3p contains three distinct nucleotides a, c and u. The associated card seq is the sequence
that is away from that of the free group of rank 2. According to our approach, this feature may be associated to a dysregulation and a disease.
The character variety is much more complicated than in the case of seeds with two distinct nucleotides. But it is not difficult to identify that the surface , with or 6, of ADE type , is part of the game.
Additionally, the Groebner basis contains the surface whose ADE type is .
The Oncomir miR-9-5p
miR-9-5p is a well known promotor or suppressor of cancer metastasis. mir-9 mainly act as a promoter of metastasis capability in breast cancer, osteosarcoma , prostate cancer and bladder cancer, while it plays the opposite roles in other cancers such as colorectal, nasopharyngal carcimona, melanoma, gastric and brain cancer [
36] [Table 1].
The seed cuuuggu of miR-9-5p contains three distinct nucleotides c, u and g. The associated card seq is that of the free group .
The Groebner basis for the character variety attached to the seed contains the cubic surface
which is of the type
: PV
. The Painlevé type is obtained with
and the change of variables
,
. The Groebner basis also contains the DP3 cubic surface:
(see
Figure 3: Left) and similar surfaces related to the solutions of PVI equation. Such surfaces are non algebraic that is not in the list provided in [
11] [Table 4].
The Oncomir miR-146b-3p
It is known that miR-146b-3p is one important regulator of the proliferation of pancreatic cancer stem cells [
37].
The seed cccugug of miR-146b-3p contains three distinct nucleotides c, g and u. The associated card seq is the sequence that is away from that of the free group . This feature may be associated to a disregulation and a disease.
The Groebner basis attached to the seed contains DP3 cubic surfaces such as the surface of ADE type and the surface the ZDE type and Painlevé form PV, shown in Figure 3: Right.
The Oncomir miR-19a-5p
miR-19a-5p is part of the mir-17-92 cluster: a NF-kB regulated family of miRNAs that promotes cell proliferation, oncogenic transformation and evasion of apoptosis. High levels of miR-19a-5p correlate with poor prognosis in pancreatic cancer [
38].
The seed guuugc of miR-19a-5p contains three distinct nucleotides c, g and u. The associated card seq is that of the free group .
The Groebner basis attached to the seed contains the DP3 cubic surface
which corresponds to a solution of the PVI equation devoid of an isolated singularity. This solution is the (octahedral) algebraic solution 30 in [
11]. A parametric plot for the modulus of this solution is in [
10].
Other DP3 cubic surfaces in the Groebner basis are of type and of type .
The Oncomir miR-181a-5p
The dysregulation of miR-181a-5p has been implicated in various types of cancer and functions as an oncomir or tumor inhibitor [
39].
The seed acaucaa of miR-181a-5p contains three distinct nucleotides a, c and u. The associated card seq is that of the free group . The Groebner basis attached to the seed contains DP3 cubic surfaces such as the surface , and which are all the ADE type . It also contains the surface of ADE type .
The Oncomir miR-15-5p
miR-15-5p participates in the pathogenesis of several cancers as well as non-malignant conditions, such as abdominal aortic aneurysm, Alzheimer’s and Parkinson’s diseases. Dysregulation of miR-15b-5p in clinical samples has been associated with poor outcome in different kinds of cancers [
40].
The seed agcagca of miR-15-5p contains three distinct nucleotides a, c and g. The associated card seq is that of the free group . The Groebner basis attached to the seed contains a DP3 cubic surface which of type : PV as well of other surfaces of the PV type.
The Oncomir miR-569
miR-569 expression levels are markedly downregulated in lunger cancer cells. miR-569 also contributes to ovarian and breast cancer cell survival and proliferation [
41].
The seed guuaaug of miR-569 contains three distinct nucleotides a, g and u. The associated card seq is the sequence that is away from that of the free group . This feature may be associated to a disregulation and a disease. The Groebner basis attached to the seed contains the DP3 cubic surfaces which is of the ADE type and which is of type .
The Oncomir miR-133b
mir-133b originally defined as a canonical muscle-specific microRNA. It has been found to show abnormal expression in various kinds of human cancer and its complex complicated regulatory networks affects the tumorigenicity and development of malignant tumors [
42].
The seed uuggucc of miR-133b-3p contains three distinct nucleotides c, g and u. The associated card seq is the sequence that is away from that of the free group . The Groebner basis attached to the seed contains the DP3 cubic surfaces , d=1 or 2, characteristic of the ADE type , surfaces such as of type and surfaces of type .
The Oncomir miR-1270b
miR-1270 plays a crucial role in the initiation and development of osteosarcoma, which is the most common bone malignancy worldwide, characterized by high morbidity and mortality [
43]. Incidently, miR-1270 is also differentially expressed in Meniere’s disease, a chronic debilitating disorder of the inner ear, characterized by fluctuating episodes of vertigo and hearing loss [
44].
The seed uggagau of miR-1270 contains three distinct nucleotides a, u and g. The associated card seq is that of the free group . The Groebner basis attached to the seed contains DP3 surfaces such as of ADE type , of type and of type . None of them belong to the Painlevé class.
3.2. Human microRNAs That Mainly Act as Tumor Suppressors
Table 2 provide a short list of miRNAs generally considered as tumor suppressors. As already mentioned, the boundary between an oncomir and a tumor suppressor is not tight. The first five miRNAs either have a card seq away from the free group
or have a Groebner basis containing simply singular surfaces in one of their -5-p or 3-p strands. But many other miRNAs in
Table 2 have the card seq of
and no simply singular surface is found in the Groebner basis. This is in accordance of our approach.
MicroRNA let-7a-5p
The let-7 family of microRNAs, first identified in C. elegans but functionally conserved from worms to human, is an important class of regulators for diverse cellular functions ranging from cell proliferation, differentiation and pluripotency to cancer development and progression [
45,
46]. let-7a is abundant in glioma and play a role in prostate and lung cancer development. Lower expression of miR-let-7a in patients with lung cancer brain metastasis was closely related to unfavorable efficacy and prognosis of radiotherapy [
47].
The seed gagguag of miR-let-7a-5p contains three distinct nucleotides a, g and u. The associated card seq is that of the free group
. The Groebner basis attached to the seed contains DP3 cubic surfaces
and
of type
and
of type
. The later surface is pictured in
Figure 4: Left. None of these surfaces are found of the Painlevé type.
The seed uauacaa of miR-let-7a-5p contains three distinct nucleotides a, c and u. The associated card seq is that of the free group . The Groebner basis attached to the seed does not contain cubics and higher order surfaces.
MicroRNA 34b-3p
The overexpression of miR-34b-3p has deen shown to suppress lung cancer cell growth, including proliferation inhibition, cell cycle arrest and increased apoptosis [
48]. Downregulation of miR-34b-3p is significantly hypermethylated and consequently downregulated, particularly in neuroblastoma patients at high risk of progression [
49].
The seed aaucacu of miR-34b-3p contains three distinct nucleotides a, c and u. The associated card seq is the sequence
that is away from that of the free group
. The Groebner basis attached to the seed contains DP3 surfaces
which is of type
, as well as
which is of type
and
which is of type
. The later surface is pictured in
Figure 4: Right.
MicroRNA 200a-5p
Expression in melanoma cells may be controlled by miR-200a-5p leading to a downregulation of surface expression for the human leukocyte antigen class I, which is linked to a reduced survival of patients [
50]. The mir-200 family acts as an oncogene in colorectal cancer [
51]. MicroRNAs from the mir-200 family are commonly associated with the inhibition of the metastatic potential of cancer cells, following inhibition of ZEB transcription factors expression and epithelial-to-mesenchymal transition [
52].
The seed aucuuac of miR-200a-5p contains three distinct nucleotides a, c and u. The associated card seq is the sequence that is away from that of the free group . The Groebner basis attached to the seed contains DP3 cubic surfaces of the ADE type and which are not in the Painlevé class.
MicroRNA 22-5p
A study revealed that miR-22-5p downregulation contributed to the malignant progression of non-small-cell lung cancer by targeting transcription factor TWIST2 [
53]. miR-22-5p may also inhibit tumor progression by sponging DNA topoisomerase II-alpha [
54].
The seed guucuuc of miR-22-5p contains three distinct nucleotides u, c and g. The associated card seq is that of the free group . The Groebner basis attached to the seed contains a cubic surface which is the DP3 surface of the ADE type .
MicroRNA 214
miR-214 is one of the fastest evolving microRNAs [
55] [Table 3]. First mir-214 was reported to promote apoptosis in HeLa cells. Presently, mir-214 is implicated in an extensive range of conditions such as cardiovascular diseases, cancers, bone formation and cell differentiation [
56].
For miR-214-5p and the short seed sequence GCCUGU, we find the DP3 surface
of type
. The reader can look at [
57] [Figure 5] for a picture. A surface
of
is also found. For a longer seed GCCUGUC, surfaces are not found to contain a cubic surface.
For miR-214-3p and the short seed sequence cagcag, we find a DP3 surface of ADE type in the corresponding Groebner basis. With the longer seed cagcagg, no cubic surface is found within the Groebner basis.
MiRNA 503-5p
The slowest evolving miRNA gene in the human species is hsa-miR-503. It regulates gene expression in various pathological processes of diseases, including carcinogenesis, angiogenesis, tissue fibrosis, and colon cancer [
58,
59].
The seed region for miR-503-5p is agcagcg. The associated card seq is that of the free group
. the Groebner basis is a rational scroll devoid of isolated singularities For a longer seed agcagcgg singular surfaces are found [
57].
MicroRNA 141-5p
miR-141-5p, an important member of the mir-200 family, has been reported to be involved in cellular proliferation, migration, invasion, and drug resistance in different kinds of human malignant tumors. It may act as a tumor suppressor via targeting gene RAB32 in the development of chronic myeloid leukemia [
60].
The seed aucuucc of miR-141-5p contains three distinct nucleotides a, u and c. The associated card seq is that of the free group . The Groebner basis attached to the seed do not contain a cubic.
MicroRNA 31-5p
miR-31 was shown to regulate a number of metastasis-related genes involved in the proliferation, cell-cycle regulation and apoptosis [
61]. miR-31-5p Is a potential circulating biomarker and therapeutic target for oral cancer [
62].
The seed ggcaaga of miR-31-5p contains three distinct nucleotides a, c and g. The associated card seq is that of the free group . The Groebner basis attached to the seed contains a cubic surface which is rational scroll devoid of isolated singularity and not of the Painlevé type.
MicroRNA 122-5p
Use of miR-122 as a cutting-edge tool for cancer treatment. Cancer cell lines revealed that mir-122 functions as an oncogenic or tumor-suppressive miRNA and examination of patient tumor samples furthermore supported the idea that mir-122 dysregulation is a crucial component in the growth of malignancies [
63].
The seed gagugug of miR-122-5p contains three distinct nucleotides a, u and g. The associated card seq is that of the free group . The Groebner basis attached to the seed do not contain a cubic.
MicroRNA 29b-5p
miR-29b-5p is a key oncomiR and therefore a target for molecular diagnosis and treatment of patients with oral squamous cell carcinoma [
64].
The seed cugguuu of miR-29b-5p contains three distinct nucleotides c, u and g. The associated card seq is that of the free group . The character variety attached to the seed contains cubics of a DP3 type, a rational scroll and a ruled surface over a genus 1 curve but none of them has an isolated singularity and they are not of the Painlevé type.
MicroRNA 143-3p
Brain metastasis is one of the secondary mortality causes for patients. It was found that miR-143–3p is upregulated in the paired brain metastasis tissues in contrast with primary cancer tissues. It may be used as a prognostic factor for in vivo progression, invasion, metastasis and survival rate of lung cancer [
65]. miR-143-3p may suppress tumorigenesis in pancreatic duct adenocarcinoma by targeting KRAS gene [
66].
The seed gagauga of miR-143-3p contains three distinct nucleotides a, u and g. The associated card seq is that of the free group . The Groebner basis attached to the seed does not contain a cubic.
MicroRNA 140-5p
The low expression of miR-140-5p is related to tumor stage or metastasis. The miR-140-5p overexpression suppressed cell proliferation and invasion in colorectal carcinoma [
67] .
The seed agugguu of miR-140-5p contains three distinct nucleotides a, u and g. The associated card seq is that of the free group . The Groebner basis attached to the seed contains a ruled surface over a genus 1 curve. There is none isolated singularity neither a Painlevé type cubic.
3.3. MicroRNA 340
mir-340 may act either as an oncogene or a tumor suppressor by targeting genes related to proliferation, apoptosis, and metastasis, as well as those associated with diagnosis, treatment, chemoresistance, and prognosis [
68]. mir-340 restricts the development of breast cancer cells by targeting numerous oncogenes. mir-340 has been shown to play a suppressive role in lung, colorectal ovarian and prostate cancers, laryngeal squamous cell carcinoma and osteosarcoma. mir-340 plays a critical role in in non-small cell lung cancer, and its overexpression restricts the growth and invasion of the corresponding cells [
69].
The seed of miR-340-5p is uauaaag and that of miR-340-3p is cguucuc. Both of them have a card seq which is that of the free group . For both of them the Groebner basis attached to the seed does no contain cubic surfaces.
3.4. MicroRNA 27
Wilms’ tumor is the most common type of renal tumor in children. There is tumor-suppressive effect of miR-27a-5p in Wilms’ tumor cells [
70]. Cervical cancer is the fourth most frequently occurring cancer and the fourth leading cause of cancer-associated mortality mong women [
71].
For both cases, the card seq associated to the group defined from the seed is . No isolated singularity is found.